OA17112A - Injection molded screening apparatuses and methods. - Google Patents

Abstract

Screening members, screening assemblies (10), methods for fabricating screening members and assemblies and methods for screening materials are provided for vibratory screening machines that incorporate the use of injection molded materials. Use of injection molded screen elements (16) provide, inter alia, for: varying screening surface configurations; fast and relatively simple screen assembly fabrication; and a combination of outstanding screen assembly mechanical and electrical properties, including toughness, wear and chemical resistance. Embodiments of the present invention use a thermoplastic injection molded material.

Description

INJECTION MOLDED SCREENING APPARATUSES AND METHODS CROSS-REFERENCE TO RELATED APPLICATIONS

The présent application daims the benefit of U.S. Provisionai Patent Application Serial Nos. 61/652,039 filed May 25, 2012, and 61/714,882 filed October 17,2012.

FIELD

The présent disdosure relates generally to material screening. More particulariy, the présent disdosure relates to screening members, screening assemblies, methods fer fabricating screening members and assemblies and methods for screening matériels.

BACKGROUND

Material screening Indudes the use of vibratory screening machines. Vibratory screening machines provide the capability to exdte an Installed screen such that matériels placed upon the screen may be separated to a desired level. Overslzed matériels are separated from undersized ma tenais. Over time, screens wear and require replacement As such, screens are designed to be replaceable.

Replacement screen assemblies must be securely fastened to a vibratory screening machine and are subjected to large vibratory forces. Replacement screens may be attached to a vibratory screening machine by tensioning members, compression members or damping members.

Replacement screen assemblies are typically made of métal or a thermoset polymer. The material and configuration of the replacement screens are spedflc to a screening application. For example, due to their relative durabiiity and capacity for fine screening, métal screens are frequently used for wet applications ln the oil and gas Industry. Traditional thermoset polymer type screens (e.g., molded polyuréthane screens), however, are not as durable and would likely not withstand the rough conditions of such wet applications and are frequently utilized in dry applications, such as applications in the mining industry.

Fabricating thermoset polymer type screens is relatively complicated, time consuming and prone to errors. Typical thermoset type polymer screens that are used with vibratory screening machines are fabrlcated by combining separate liquids (e.g., polyester, polyether and a curative) that chemically react and then allowing the mixture to cure over a period of time In a mold. When fabricating screens with fine openings, e.g., approximately 43 microns to approximately 100 microns, this process can be extremeiy difficult and time consuming. indeed, to croate fine openings in a screen, the channels in the molds that the liquid travels through hâve to be very small (e.g., on the order of 43 microns) and all too often the liquid does not reach all the cavities in the mold. As a resuit, compiicated procedures are often implemented that require close attention to pressures and températures. Since a relatively large single screen (e.g., two feet by three feet or iarger) is made in a mold, one flaw (e.g., a hole, Le., a place where the liquid did not reach) will ruin the entire screen. Thermoset polymer screens are typically fabricated by molding an entire screen assembly structure as one large screening piece and the screen assembly may hâve openings ranging from approximately 43 microns to approximately 4000 microns In size. The screening surface of conventional thermoset polymer screens normally hâve a uniform fiat configuration.

Thermoset polymer screens are relatively flexible and are often secured to a vibratory screening machine using tensloning members that pull the side edges of the thermoset polymer screen away from each other and secure a bottom surface of the thermoset polymer screen against a surface of a vibratory screening machine. To prevent deformation when being tensloned, thermoset polymer assemblies may be molded with aramid fibers that run in the tensloning direction (see, e.g., U.S. Patent No. 4,819,809). if a compression force were applied to the side edges of the typical thermoset polymer screens It would buckle or crimp, thereby rendering the screening surface relatively Ineffective.

In contrast to thermoset polymer screens, métal screens are rigid and may be compressed or tensioned onto a vibratory screening machine. Métal screen assemblies are often fabricated from multiple métal components. The manufacture of métal screen assemblies typically inciudes: fabricating a screening material, often three layers of a woven wire mesh; fabricating an apertured meta) backlng plate; and bonding the screening material to apertured métal backing plate. The layers of wire cloth may be finely woven with openings In the range of approximately 30 microns to approximately 4000 microns. The entire screening surface of conventional métal assemblies Is normally a relatively uniform fiat configuration or a relatively uniform corrugated configuration.

Criticai to screening performance of screen assemblies (thermoset polymer assemblies and métal type assemblies) for vibratory screening machines are the size of the openings In the screening surface, structurai stability and durabliity of the screening surface, structural stability of the entire unit, chemical properties of the components of the unit and ability of the unit to perform in various températures and environments. Drawbacks to conventional métal assemblies include lack of structure stability and durabliity of the screening surface formed by the woven wire mesh layers, blinding (plugglng of screening openings by particles) of the screening surface, weight of the overall structure, time and cost associated with the fabrication or purchase of each of the component members, and assembly time and costs. Because wire cloth Is often outsourced by screen manufacturera, and is frequently purchased from weavera or wholesalera, quality control can be extremeiy difficult and there are frequently problems with wire cloth. Flawed wire cloth may resuit In screen performance problems and constant monitoring and testlng is required.

One of the blggest problems with conventional métal assemblies Is blinding. A new métal screen may Initiaiiy hâve a relatively large open screening area but over time, as the screen Is exposed to particles, screening openings plug (i.e., blind) and the open screening area, and effectiveness of the screen itself, is reduced relatively qulckly. For example, a 140 mesh screen assembly (having three layers of screen cloth) may hâve an Initial open screening area of 20-24%. As the screen Is used, however, the open screening area may be reduced by 50% or more.

Conventional métal screen assemblies also lose large amounts of open screening area because of their construction, which Includes adheslves, backing plates, plastic sheets bondîng layers of wire cloth together, etc.

Another major problem with conventional métal assemblies Is screen life. Conventional métal assemblies don’t typically fait because they get wom down but Instead fail due to fatigue. That is, the wlres of the woven wire cloth often actually break due to the up and down motion they are subject to durlng vibratory loading.

Drawbacks to conventional thermoset polymer screens also include lack of structure stability and durabllity. Additional drawbacks Include Inability to withstand compression type loading and Inability to withstand high températures (e.g., typically a thermoset polymer type screen . will begin to fail or expérience performance problems at températures above 130’F, espedally screens with fine openings, e.g., approximately 43 microns to approximately 100 microns). Further, as dlscussed above, fabrication Is compllcated, time consumlng and prone to errors. Also, the molds used to fabricate thermoset polymer screens are expensive and any flaw or the sllghtest damage thereto will ruln the entire mold and require replacement, which may resuit In costly downtime in the manufacturing process.

Another drawback to both conventional métal and thermoset polymer screens Is the limitation of screen surface configurations that are available. Existing screening surfaces are fabricated with relatively uniform opening slzes throughout and a relatively unlform surface configuration throughout, whether the screening surface Is fiat or undulating.

The conventional polymer type screens referenced in U.S. Provisional Application No.

61/652,039 (also referred to therein as traditionai polymer screens, existing polymer screens, typical polymer screens or slmply polymer screens) refer to the conventional thermoset polymer screens described in U.S. Provisional Patent Application Serial No. 61/714,882 and the conventional thermoset polymer screens described herein (also referred to herein and In U.S.

Provlslonal Patent Application Serial No. 61/714,882 as traditions! thermoset polymer screens, exlsting thermoset polymer screens, typical thermoset polymer screens or simply thermoset screens). Accordingly, the conventional polymer type screens referenced In U.S. Provisional Application No. 61/652,039 are the same conventional thermoset polymer screens référencé herein, and In U.S. Provisional Patent Application Serial No. 61/714,882, and may be fabricated with extremely smal! screening openings (as described herein and in U.S. Provisional Patent Application Serial No. 61/714,882) but hâve ali the drawbacks (as described herein and In U.S. Provisional Patent Application Serial No. 61/714,882) regardlng conventional thermoset polymer screens, inciuding lack of structural stability and durability, inability to withstand compression type loading, inability to withstand high températures and compticated, time consuming, errer prône fabrication methods.

There Is a need for versatile and Improved screening members, screening assemblies, methods for fabricating screening members and assemblies and methods for screening materiaîs for vlbratory screening machines that Incorporate the use of Injection molded materiaîs (e.g., thermoplastics) having Improved mechanical and chemical properties.

SUMMARY

The présent disclosure is an improvement over exlsting screen assemblies and methods for screening and fabricating screen assemblies and parts thereof. The présent invention provides extremely versatile and improved screening members, screening assemblies, methods for fabricating screening members and assemblies and methods for screening materiaîs for vibratory screening machines that incorporate the use of injection molded materiaîs having improved properties, inciuding mechanical and chemical properties. In certain embodiments of the présent invention a thermoplastic is used as the Injection molded material. The présent Invention is not limited to thermoplastic Injection molded materiais and In embodiments of the présent Invention other materiais may be used that hâve similar mechanical and/or chemical properties. In embodiments of the présent invention, multiple injection molded screen éléments are securely attached to subgrid structures. The subgrids are fastened together to form the screen assembly structure, which has a screening surface Inciuding multiple screen éléments. Use of Injection molded screen éléments with the various embodiments described herein provide, Inter alla, for. varying screening surface configurations; fast and relatively simple screen assembly fabrication; and a combination of outstanding screen assembly mechanical, chemical and electrical properties, Inciuding toughness, wear and chemical résistance.

Embodiments of the présent invention include screen assemblies that are configured to hâve relatively large open screening areas while having structurally stable small screening 4 openings for fine vibratory screening applications. In embodiments of the présent Invention, the screening openings are very smail (e.g., as small as approximately 43 microns) and the screen éléments are large enough (e.g., one Inch by one inch, one inch by two Inches, two Inches by three Inches, etc.) to make It practical to assemble a complété screen assembly screening surface (e.g., two feet by three feet, three feet by four feet, etc.). Fabricating small screening openings for fine screening applications requlres Injection molding very small structural members that actually form the screening openings. These structural members are Injection molded to be formed integrally with the screen element structure. Importantly, the structural members are small enough (e.g., In certain applications they may be on the order of approximately 43 microns In screening surface width) to provide an effective overall open screening area and form part of the entire screen element structure that Is large enough (e.g., two inches by three Inches) to make It practical to assemble a relatively large complété screening surface (e.g., two feet by three feet) therefrom.

In one embodiment of the présent Invention a thermoplastic material Is injection molded to form screening éléments. Previously thermoplastics hâve not been used with the fabrication of vibratory screens with fine size openings (e.g., approximately 43 microns to approximately 1000 microns) because It would be extremely difficult, if not Impossible, to thermoplastic Injection mold a single relatively large vibratory screening structure having fine openings and obtain the open screening area necessary for compétitive performance in vibratory screening applications.

According to an embodiment of the présent disclosure, a screen assembly Is provided that: is structurally stable and can be subjected to various loading conditions, Including compression, tenslonlng and clamplng; can withstand large vibrational forces; Includes multiple injection molded screen éléments that, due to their relatively small size, can be fabricated with extremely small opening stzes (having dimensions as small as approximately 43 microns); éliminâtes the need for wirecloth; Is lightweight; Is recyclable; Is simple and easy to assemble; can be fabricated in multiple different configurations, Including having various screen opening sizes throughout the screen and having various screening surface configurations, e.g., various combinations of fiat and undulattng sections; and can be fabricated with application-specific materials and nanomaterials. Still further, each screen assembly may be customized to a spécifie application and can be simply and easily fabricated with various opening sizes and configurations depending on the spécifications provided by an end user. Embodiments of the présent disclosure may be applied to various applications, Including wet and dry applications and may be applied across various industries. The présent invention Is not limited to the oil and gas Industry and the minlng industry, It may be utilized In any industry that requires séparation of materials using vibratory screenings machines, Including pulp and paper, chemical, pharmaceuticals and others.

ln an example embodiment of the présent Invention, a screen assembly Is provided that substantially Improves screening of materials using a thermoplastic Injection molded screen element. Multiple thermoplastic polymer Injection molded screen éléments are securely attached to subgrid structures. The subgrids are fastened together to form the screen assembly structure, which has a screening surface Including multiple screen éléments. Each screen element and each subgrid may hâve different shapes and configurations. Thermoplastic Injection molding Individual screen éléments allows for précisé fabrication of screening openings, which may hâve dimensions as small as approximately 43 microns. The grid framework may be substantially rigid and may provide durability against damage or deformation under the substantlal vibratory load burdens It is subjected to when secured to a vibratory screening machine. Moreover, the subgrids, when assembled to form the complété screen assembly, are strong enough not only to withstand the vibratory loading, but also the forces required to secure the screen assembly to the vibratory screening machine, Including large compression loads, tension loads and/or clamping loads. Still further, the openings In the subgrids structurally support the screen éléments and transfer vibrations from the vibratory screening machine to the éléments forming the screening openings thereby optimlzing screening performance. The screen éléments, subgrids and/or any other component of the screen assembly may Indude nanomaterials and/or glass fibers that, in addition to other benefits, provide durability and strength.

According to an example embodiment of the présent disdosure, a screen assembly Is provided having a screen element Including a screen element screening surface with a sériés of screening openings and a subgrid induding multiple elongated structural members forming a grid framework having grid openings. The screen element spans at least one of the grid openings and Is attached to a top surface of the subgrid. Multiple independent subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface having multiple screen element screening surfaces. The screen element Indudes substantially parallel end portions and substantially paralleî side edge portions substantially perpendicular to the end portions. The screen element further Indudes a first screen element support member and a second screen element support member orthogonal to the first screen element support member. The first screen element support member extends between the end portions and is approximately parallel to the side edge portions. The second screen element support member extends between the side edge portions and Is approximately parallel to the end portions. The screen element indudes a first sériés reinforcement members substantially parallel to the side edge portions and a second sériés of reinforcement members substantially parallel to the end portions. The screen element screening surface indudes screen surface éléments forming the screening openings. The end portions, side edge portions, first and second support members and first and second sériés of reinforcement members structurally stabilize screen surface éléments and screening openings. The screen element Is formed as a single thermoplastic injection molded piece.

The screening openings may be rectangular, square, circular, and ovai or any other shape. The screen surface éléments may run parailel to the end portions and form the screening openings. The screen surface éléments may also run perpendicular to the end portions and form the screen openings. Different combinations of rectangular, square, circular and oval screening openings (or other shapes) may be incorporated together and depending on the shape utilized may run parailel and/or perpendicular to the end portions.

The screen surface éléments may run parailel to the end portions and may be elongated members forming the screening openings. The screening openings may be elongated slots having a distance of approximately 43 microns to approximately 4000 microns between inner surfaces of adjacent screen surface éléments. In certain embodiments, the screen openings may hâve a distance of approximately 70 microns to approximately 180 microns between inner surfaces of adjacent screen surface éléments. In other embodiments, the screening openings may hâve a distance of approximately 43 microns to approximately 106 microns between Inner surfaces of adjacent screen surface éléments. In embodiments of the présent invention, the screening openings may hâve a wldth and a length, the wldth may be about 0.043 mm to about 4 mm and the length may be about 0.086 mm to about 43 mm. In certain embodiments, the width to length ratio may be approximately 1:2 to approximately 1:1000.

Multiple subgrids of varying sizes may be combined to form a screen assembly support structure for screen éléments. Alternative^, a single subgrid may be thermoplastic Injection molded, or otherwlse constructed, to form the entire screen assembly support structure for multiple Individual screen éléments.

In embodiments that use multiple subgrids, a first subgrid may Inciude a first base member having a first fastener that mates with a second fastener of a second base member of a second subgrid, the first and second fasteners securing the first and second subgrids together. The first fastener may be a clip and the second fastener may be a dip aperture, wherein the clip snaps Into the dip aperture and securely attaches the first and second subgrids together.

The first and second screen element support members and the screen element end portions may Indude a screen element attachment arrangement configured to mate with a subgrid attachment arrangement. The subgrid attachment arrangement may Indude elongated attachment members and the screen element attachment arrangement may indude attachment apertures that mate with the elongated attachment members securely attaching the screen element to the subgrid. A portion of the elongated attachment members may be configured to extend through the screen 7 element attachment apertures and sllghtly above the screen element screening surface. The attachment apertures may Include a tapered bore or may simpiy include an aperture without any tapering. The portion of the elongated attachment members above the screening element screening surface may be melted and may fiil the tapered bore, fastening the screen element to the subgrid. Altemativeiy, the portion of the elongated attachment members that extends through and above the aperture in screening element screening surface may be melted such that It forms a bead on the screening element screening surface and festens the screen element to the subgrid.

The elongated structural members may Include substantiaily parallel subgrid end members and substantiaily parallel subgrid side members substantiaily perpendlcular to the subgrid end members. The elongated structural members may further indude a first subgrid support member and a second subgrid support member orthogonal to the first subgrid support member. The first subgrid support member may extend between the subgrid end members and may be approximately parallel to the subgrid side members. The second subgrid support member may extend between the subgrid side members and may be approximately parallel to the subgrid end members, and substantiaily perpendicular to the subgrid edge members.

The grid framework may indude a first and a second grid framework forming a first and a second grid opening. The screen éléments may indude a first and a second screen element. The subgrid may hâve a ridge portion and a base portion. The first and second grid frameworks may include first and second angular surfaces that peak at the ridge portion and extend downwardly from the peak portion to the base portion. The first and second screen éléments may span the first and second angular surfaces, respectively.

According to an example embodiment of the présent Invention, a screen assembly is provided having a screen element induding a screen element screening surface with a sériés of screening openings and a subgrid Including multiple elongated structural members forming a grid framework having grid openings. The screen element spans at least one grid opening and is secured to a top surface of the subgrid. Multiple subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces. The screen element is a single thermopiastic injection moided piece.

The screen element may Indude substantiaily parallel end portions and substantiaily parallel side edge portions substantiaily perpendicular to the end portions. The screen element may further include a first screen element support member and a second screen element support member orthogonal to the first screen element support member. The first screen element support member may extend between the end portions and may be approximately parallel to the side edge portions. The second screen element support member may extend between the side edge portions and may 8 be approximately parallel to the end portions. The screen element may include a first sériés reinforcement members substantially parallel to the side edge portions and a second sériés of reinforcement members substantially parallel to the end portions. The screen element may include elongated screen surface éléments running parallel to the end portions and forming the screening openings. The end portions, side edge portions, first and second support members, first and second sériés of reinforcement members may structuraily stabilize the screen surface éléments and the screening openings.

The first and second sériés of reinforcement members may hâve a thickness less than a thickness of the end portions, side edge portions and the first and second screen element support members. The end portions and the side edge portions and the first and second screen element support members may form four rectangular areas. The first sériés of reinforcement members and the second sériés of reinforcement members may form multiple rectangular support grids within each of the four rectangular areas. The screening openings may hâve a width of approximately 43 microns to approximately 4000 microns between inner surfaces of each of the screen surface éléments, in certain embodiments, the screening openings may hâve a width of approximately 70 microns to approximately 180 microns between Inner surfaces of each of the screen surface éléments. In other embodiments, the screening openings may hâve a width of approximately 43 microns to approximately 106 microns between Inner surfaces of each of the screen surface éléments. In embodiments of the présent invention, the screening openings may hâve a width of about 0.043 mm to about 4 mm and length of about 0.086 mm to about 43 mm. in certain embodiments, the width to length ratio may be approximately 1:2 to approximately 1:1000.

The screen éléments may be flexible.

The subgrid end members, the subgrid side members and the first and second subgrid support members may form eight rectangular grid openings. A first screen element may span four of the grid openings and a second screen element may span the other four openings.

A central portion of the screening element screening surface may slightly flex when subject to a ioad. The subgrid may be substantially rigid. The subgrid may also be a single thermoplastic injection molded piece. At least one of the subgrid end members and the subgrid side members may include fasteners configured to mate with fasteners of other subgrids, which fasteners may be clips and dip apertures that snap Into place and securely attach the subgrids together.

The subgrid may include: substantially parallel triangular end pièces, triangular middle pièces substantially parallel to the triangular end pièces, a first and second mld support substantially perpendicular to the triangular end pièces and extending between the triangular end pièces, a first and second base support substantially perpendicular to the triangular end pièces and extending the between the triangular end pièces and a centrai ridge substantially perpendicular to 9 the triangular end pièces and extending the between the triangular end pièces. A first edge of the triangular end pièces, the triangular middle pièces, and the first mid support, the first base support and the centrai ridge may form a first top surface of the subgrid having a first sériés of grid openings. A second edge of the triangular end pièces, the triangular middle pièces, and the second mid support, the second base support and the central ridge may form a second top surface of the subgrid having a second sériés of grid openings. The first top surface may siope down from the central ridge to the first base support and the second top surface may siope down from the central ridge to the second base support. A first and a second screen element may span the first sériés and second sériés of grid openings, respectively. The first edges of the triangular end pièces, the triangular middle pièces, the first mid support, the first base support and the central ridge may Include a first subgrid attachment arrangement configured to securely mate with a first screen element attachment arrangement of the first screen element. The second edges of the triangular end pièces, the triangular middle pièces, the second mid support, the second base support and the central ridge may Include a second subgrid attachment arrangement configured to secureiy mate with a second screen element attachment arrangement of the second screen element. The first and second subgrid attachment arrangements may Include elongated attachment members and the first and second screen element attachment arrangements may include attachment apertures that mate with the elongated attachment members thereby securely attaching the first and second screen éléments to the first and second subgrids, respectively. A portion of the elongated attachment members may extend through the screen element attachment apertures and slightly above a first and second screen element screening surface.

The first and second screen eiements each may indude substantiaily parallel end portions and substantiaily parallel side edge portions substantiaily perpendicular to the end portions. The first and second screen éléments may each Include a first screen element support member and a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallel to the side edge portions, the second screen element support member extending between the side edge portions and may be approximately parallel to the end portions. The first and second screen éléments may each Indude a first sériés reinforcement members substantiaily parallel to the to the side edge portions and a second sériés of reinforcement members substantiaily parallel to the end portions. The first and second screen éléments may each Indude elongated screen surface éléments runnlng parallel to the end portions and forming the screening openings. The end portions, side edge portions, first and second support members, first and second sériés of reinforcement members may structurally stabilize screen surface éléments and screening openings.

One of the first and second base supports may include fasteners that secure the multiple subgrids together, which fasteners may be clips and dip apertures that snap Into place and secureiy attach subgrids together.

The screen assembly may indude a first, a second, a third and a fourth screen element. The first sériés of grid openings may be eight openings formed by the first edge of the triangular end pièces, the triangular middle pièces, and the first mid support, the first base support and the centrai ridge. The second sériés of grid openings may be eight openings formed by the second edge of the triangular end pièces, the triangular middle pièces, the second mid support, the second base support and the centrai ridge. The first screen element may span four of the grid openings of the first sériés of grid openings and the second screen element may span the other four openings of the first sériés of grid openings. The third screen element may span four of the grid openings of the second sériés of grid openings and the fourth screen element may span the other four openings of the second sériés of grid openings. A central portion of the first, second, third and fourth screening element screening surfaces may slightly flex when subject to a load. The subgrid may be substantially rigid and may be a single thermopiastic injection molded piece.

According to an example embodiment of the présent disdosure, a screen assembly Is providing having a screen element Induding a screen element screening surface with screening openings and a subgrid including a grid framework with grid openings. The screen element spans the grid openings and Is attached to a surface of the subgrid. Multiple subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface that indudes multiple screen element screening surfaces. The screen element is a thermoplastic injection molded piece.

The screen assembly may also include a first thermopiastic injection molded screen element and a second thermoplastic injection molded screen element and the grid framework may Include a first and second grid framework forming a first grid opening and a second grid opening. The subgrid may indude a ridge portion and a base portion, the first and second grid frameworks induding first and second angular surfaces that peak at the ridge portion and extend downwardly from the peak portion to the base portion. The first and second screen éléments may span the first and second angular surfaces, respectively. The first and second angular surfaces may Indude a subgrid attachment arrangement configured to secureiy mate with a screen element attachment arrangement. The subgrid attachment arrangement may indude elongated attachment members and the screen element attachment arrangement may Indude apertures that mate with the elongated attachment members thereby secureiy attachlng the screen éléments to the subgrid.

The subgrid may be substantially rigid and may be a single thermoplastic injection molded piece. A section of the base portion may Indude a first and a second fastener that secure the 11 subgrid to a third and a fourth fastener of another subgrid. The first and third fasteners may be clips and the second and fourth fasteners may be clip apertures. The clips may snap Into clip apertures and securely attach the subgrid and the another subgrid together.

The subgrids may form a concave structure and the continuous screen assembly screening surface may be concave. The subgrids may form a fiat structure and the continuous screen assembly screening surface may be fiat. The subgrids may form a convex structure and the continuous screen assembly screening surface may be convex.

The screen assembly may be configured to form a predetermined concave shape when subjected to a compression force by a compression assembly of a vibratory screening machine against at least one slde member of the vibratory screen assembly when placed In the vibratory screening machine. The predetermined concave shape may be determined In accordance with a shape of a surface of the vibratory screening machine. The screen assembly may hâve a mating surface mating the screen assembly to a surface of the vibratory screening machine, which mating surface may be rubber, métal (e.g., steel, alumlnum, etc.), a composite material, a plastic material or any other suitable material. The screen assembly may Include a mating surface configured to Interface with a mating surface of a vibratory screening machine such that the screen assembly Is guided Into a fixed position on the vibratory screening machine. The mating surface may be formed In a portion of at least one subgrid. The screen assembly mating surface may be a notch formed In a comer of the screen assembly or a notch formed approximately In the mlddle of a slde edge of the screen assembly. The screen assembly may hâve an arched surface configured to mate with a concave surface of the vibratory screening machine. The screen assembly may hâve a substantially rigid structure that does not substantially deflect when secured to the vibratory screening machine. The screen assembly may Include a screen assembly mating surface configured such that It forms a predetermined concave shape when subjected to a compression force by a member of a vibratory screening machine. The screen assembly mating surface may be shaped such that it Interfaces with a mating surface of the vibratory screening machine such that the screen assembly may be guided Into a predetermined location on the vibratory screening machine. The screen assembly may Include a load bar attached to an edge surface of the subgrid of the screen assembly, the load bar may be configured to dîstribute a load across a surface of the screen assembly. The screen assembly may be configured to form a predetermined concave shape when subjected to a compression force by a compression member of a vibratory screening machine against the load bar of the vibratory screen assembly. The screen assembly may hâve a concave shape and may be configured to deflect and form a predetermined concave shape when subjected to a compression force by a member of a vibratory screening machine.

A first set of the subgrids may be formed Into center support frame assembles having a first fastener arrangement. A second set of the subgrids may be formed Into a first end support frame assembiy having a second fastener arrangement. A third set of the subgrids may be formed Into a second end support frame assembiy having a third fastener arrangement. The first, second, and 5 third fastener arrangements may secure the first and second end support frames to the center support assemblies. A side edge surface of the first end support frame assembiy may form a first end of the screen assembiy. A side edge surface of the second end support frame arrangement may form a second end of the screen assembiy. An end surface of each of the first and second end support frame assemblies and center support frame assemblies may cumulatively form a first 10 and a second side surface of the complété screen assembiy. The first and second side surfaces of the screen assembiy may be substantially parallel and the first and second end surfaces of the screen assembiy may be substantially parallel and substantially perpendicular to the side surfaces of the screen assembiy. The side surfaces of the screen assembiy may indude fasteners configured to engage at ieast one of a binder bar and a load distribution bar. The subgrids may 15 Include side surfaces such that when Individual subgrids are secured together to form the first and second end support frame assemblies and the center support frame assembiy that the first and second end support frame assemblies and the center support frame assembiy each form a concave shape. The subgrids may Indude side surfaces shaped such that when Individual subgrids are secured together to form the first and second end support frame assemblies and the 20 center support frame assembiy that the first and second end support frame assemblies and the center support frame assembiy each form a convex shape.

The screen éléments may be affixed to the subgrids by at least one of a mechanical arrangement, an adheslve, heat staking and ultrasonlc welding.

According to an example embodiment of the présent disdosure, a screen element ls 25 provided having: a screen element screening surface with screen surface éléments forming a sériés of screening openings; a pair of substantially parallel end portions; a pair of substantially parallel side edge portions substantially perpendicular to the end portions; a first screen element support member; a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and 30 being approximately parallel to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallel to the end portions and substantially perpendicular to the side edge portions; a first sériés of reinforcement members substantially parallel to the side edge portions; and a second sériés of reinforcement members substantially parallel to the end portions. The screen surface éléments run parallel to the end 35 portions. The end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabllize screen surface éléments and screening openings, and the screen element is a single thermoplastic injection molded piece.

According to an exampie embodiment of the présent disclosure, a screen element Is provided having a screen element screening surface with screen surface éléments forming a sériés of screening openings; a pair of substantially paraliel end portions; and a pair of substantially parallei side edge portions substantially perpendicuiar to the end portions. The screen element is a thermopiastic injection moided piece.

The screen element may also hâve a first screen element support member; a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallei to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallei to the end portions; a first sériés of reinforcement members substantially parallei to the side edge portions; and a second sériés of reinforcement members substantially parallei to the end portions. The screen surface éléments may run parallei to the end portions. In certain embodiments, the screen surface éléments may also be configured to run perpendicuiar to the end portions. The end portions, side edge portions, first and second support members, first and second sériés of reinforcement members may structurally stabilize screen surface éléments and screening openings.

The screen element may also hâve a screen element attachment arrangement molded Integrally with the screen element and configured to mate with a subgrid attachment arrangement. Multiple subgrids may form a screen assembly and the screen assembly may hâve a continuous screen assembly screening surface that Includes multiple screen element screening surfaces.

According to an example embodiment of the présent disclosure, a method for fabricatlng a screen assembly for screening materials is provided that indudes: determining screen assembly performance spécifications for the screen assembly; determining a screening opening requirement for a screen eiement based on the screen assembly performance spécifications, the screen element induding a screen element screening surface having screening openings; determining a screen configuration based on the screen assembly performance spécifications, the screen configuration Induding having the screen éléments arranged In at least one of fiat configuration and a nonflat configuration; Injection molding the screen éléments with a thermoplastic material; fabricatlng a subgrid configured to support the screen éléments, the subgrid having a grid framework with grid openings wherein at least one screen element spans at least one grid opening and Is secured to a top surface of the subgrid, the top surface of each subgrid Induding at least one of a fiat surface and a nonflat surface that receives the screen éléments; attaching the screen éléments to the subgrids; attaching multiple subgrid assemblies together to form end screen frames 14 and center screen frames; attaching the end screen frames to the center screen trames to form a screen frame structure; attaching a first binder bar to a first end of the screen frame structure; and attaching a second binder bar to a second end of the screen frame structure to form the screen assembly, the screen assembly having a continuous screen assembly screening surface composed 5 of multiple screen element screening surfaces.

The screen assembly performance spécifications may Include at least one of dimensions, material requirements, open screening area, eut point, and capacity requirements for a screening application. A handle may be attached to the binder bar. A tag may be attached to the binder bar, which tag may include a performance description of the screen assembly. At least one of the 10 screen element and the subgrid may be a single thermoplastic Injection molded piece. The thermoplastic material may Include a nanomateriai. The subgrid may include at least one base member having fasteners that mate with fasteners of other base members of other subgrids and secure the subgrids together. The fasteners may be clips and clip apertures that snap Into place and securely attach the subgrids together.

According to an example embodiment of the présent disclosure, a method for fabricating a screen assembly for screening matériels is provided by Injection moldlng a screen element with a thermopiastic material, the screen element including a screen element screening surface having screening openings; fabricating a subgrid that supports the screen element, the subgrid having a grid framework with grid openings, the screen element spannlng at least one grid opening;

securing the screen element to a top surface of the subgrid; and attaching multiple subgrid assemblies together to form the screen assembly, the screen assembly having a continuous screen assembly screening surface made of multiple screen element screening surfaces. The method may also include attaching a first binder bar to a first end of the screen assembly and attaching a second binder bar to a second end of the screen assembly. The first and second binder bars may 25 blnd the subgrids together. The binder bar may be configured to distribute a load across the first and second ends of the screen assembly. The thermoplastic material may Include a nanomateriai.

According to an example embodiment of the présent disclosure, a method for screening a material Is provided by attaching a screen assembly to a vlbratory screening machine, the screen assembly Including a screen element having a sériés of screening openings forming a screen 30 element screening surface and a subgrid Including multiple elongated structural members forming a grid framework having grid openings. Screen éléments span grid openings and are secured to a top surface of the subgrid. Multiple subgrids are secured together to form the screen assembly. The screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces. The screen element Is a single thermoplastic Injection moided 35 piece. The material Is screened using the screen assembly.

According to an example embodiment of the présent disclosure, a method for screening a material Is provided Including attachlng a screen assembly to a vibra tory screening machine and forming a top screening surface of the screen assembly Into a concave shape. The screen assembly includes a screen element having a sériés of screening openings forming a screen element screening surface and a subgrid Including multiple elongated structural members forming a grid framework having grid openings. Screen éléments span grid openings and are secured to a top surface ofthe subgrid. Multiple subgrids are secured together to form the screen assembly and the screen assembly has a contînuous screen assembly screening surface comprised of multiple screen element screening surfaces. The screen element is a single thermoplastic injection molded piece. The material is screened using the screen assembly.

Example embodiments of the présent disclosure are described in more detail below with reference to the appended Figures.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 Is an isométrie view of a screen assembly, according to an exemplary embodiment of the présent invention.

Figure 1A is an enlarged view of a break out portion of the screen assembly shown in Figure 1. Figure 1B is a bottom isométrie view the screen assembly shown ln Figure 1.

Figure 2 Is an Isométrie top view of a screen element, according to an exemplary embodiment of the présent Invention.

Figure 2A Is a top view of the screen element shown ln Figure 2.

Figure 2B is a bottom isométrie view ofthe screen element shown in Figure 2.

Figure 2C Is a bottom view of the screen element shown ln Figure 2.

Figure 2D is an enlarged top view of a break out portion ofthe screen element shown ln Figure 2. Figure 3 is a top isométrie view of an end subgrid, according to an exemplary embodiment of the présent Invention.

Figure 3A Is a bottom Isométrie view ofthe end subgrid shown in Figure 3.

Figure 4 Is a top Isométrie view of a center subgrid, according to an exemplary embodiment of the présent invention.

Figure 4A is a bottom isométrie view of the center subgrid shown ln Figure 4.

Figure 5 is a top isométrie view of a binder bar, according to an exemplary embodiment of the présent invention.

Figure 5A Is a bottom Isométrie view of the binder bar shown ln Figure 5.

Figure 6 Is an Isométrie view of a screen subassembly, according to an exemplary embodiment of the présent Invention.

Figure 6A Is an exploded view of the subassembly shown in Figure 6.

Figure 7 is a top view ofthe screen assembly shown in Figure 1.

Figure 7A Is an enlarged cross-section of Section A-A of the screen assembly shown in Figure 7.

Figure 8 Is a top isométrie view of a screen assembly partialiy covered with screen éléments, according to an exemplary embodiment of the présent invention.

Figure 9 Is an exploded isométrie view of the screen assembly shown in Figure 1.

Figure 10 Is an exploded Isométrie view of an end subgrid showing screen éléments prior to attachment to the end subgrid, according to an exemplary embodiment of the présent invention.

Figure 10A is an isométrie view of the end subgrid shown in Figure 10 having the screen éléments attached thereto.

Figure 10B is a top view ofthe end subgrid shown In Figure 10A.

Figure 10C Is a cross-section of Section B-B of the end subgrid shown In Figure 10A.

Figure 11 is an exploded isométrie view of a center subgrid showing screen éléments prior to attachment to the center subgrid, according to an exemplary embodiment of the présent Invention.

Figure 11A is an isométrie view of the center subgrid shown in Figure 11 having the screen éléments attached thereto.

Figure 12 is an Isométrie view of a vibratory screening machine having screen assemblies with concave screening surfaces installed thereon, according to an exemplary embodiment of the présent Invention.

Figure 12A Is an enlarged Isométrie view of the discharge end of the vibratory screening machine shown In Figure 12.

Figure 12B is a front view of the vibratory screening machine shown in Figure 12.

Figure 13 is an isométrie view of a vibratory screening machine with a single screening surface having screen assemblies with concave screening surfaces installed thereon, according to an exemplary embodiment of the présent invention.

Figure 13A is a front view of the vibratory screening machine shown in Figure 13.

Figure 14 Is a front view of a vibratory screening machine having two separate concave screening surfaces with preformed screen assemblies installée! upon the vibratory screening machine, according to an exemplary embodiment of the présent invention.

Figure 15 is a front view of a vibratory screening machine having a single screening surface with a 5 preformed screen assembly installée! upon the vibratory screening machine, according to an exemplary embodiment of the présent Invention.

Figure 16 is an isométrie view of an end support frame subassembly, according to an exemplary embodiment of the présent invention.

Figure 16A is an exploded isométrie view of the end support frame subassembly shown in Figure 10 16.

Figure 17 is an Isométrie view of a center support frame subassembly, according to an exemplary embodiment of the présent invention.

Figure 17A is an exploded isométrie view of the center support frame subassembly shown in Figure 17.

Figure 18 Is an exploded Isométrie view of a screen assembly, according to an exemplary embodiment of the présent invention.

Figure 19 Is a top isométrie view of a fiat screen assembly, according to an exemplary embodiment of the présent invention.

Figure 20 is a top Isométrie view of a convex screen assembly, according to an exemplary 20 embodiment of the présent invention.

Figure 21 Is an Isométrie view of a screen assembly having pyramidal shaped subgrids, according to an exemplary embodiment of the présent invention.

Figure 21A is an enlarged view of section D of the screen assembly shown in Figure 21.

Figure 22 is a top Isométrie view of a pyramidal shaped end subgrid, according to an exemplary 25 embodiment of the présent invention.

Figure 22A is a bottom isométrie view of the pyramidal shaped end subgrid shown in Figure 22.

Figure 23 is a top Isométrie view of a pyramidal shaped center subgrid, according to an exemplary embodiment of the présent invention.

Figure 23A is a bottom isométrie view of the pyramidal shaped center subgrid shown In Figure 23.

Figure 24 is an isométrie view of a pyramidal shaped subassembly, according to an exemplary embodiment of the présent invention.

Agure 24A is an exploded isométrie view of the pyramidal shaped subassembly shown ln Figure

24.

Figure 24B is an exploded Isométrie view of a pyramidal shaped end subgrid showing screen éléments prior to attachment to the pyramidal shaped end subgrid.

Figure 24C is an isométrie view of the pyramidal shaped end subgrid shown in Figure 24B having the screen éléments attached thereto.

Figure 24D Is an exploded isométrie view of a pyramidal shaped center subgrid showing screen éléments prior to attachment to the pyramidal shaped center subgrid, according to an exemplary embodiment of the présent invention.

Agure 24E is an Isométrie view of the pyramidal shaped center subgrid shown ln Figure 24D having the screen éléments attached thereto.

Figure 25 Is a top view of a screen assembly having pyramidal shaped subgrids, according to an exemplary embodiment of the présent Invention.

Figure 25A is a cross-section view of Section C-C of the screen assembly shown ln Figure 25.

Figure 25B is an enlarged view of Section C-C shown ln Figure 25A.

Agure 26 Is an exploded Isométrie view of a screen assembly having pyramidal shaped and fiat subassemblies, according to an exemplary embodiment of the présent Invention.

Figure 27 Is an Isométrie view of a vibratory screening machine with two screening surfaces having assemblies with concave screening surfaces installed thereon wherein the screen assemblies 20 Include pyramidal shaped and fiat subassemblies, according to an exemplary embodiment of the présent Invention.

Agure 26 is a top isométrie view of a screen assembly having pyramidal shaped and fiat subgrids without screen éléments, according to an exemplary embodiment of the présent Invention.

Agure 29 is a top isométrie view of the screen assembly shown ln Figure 28 where the subgrids are 25 partially covered with screen éléments.

Figure 30 Is a front view of a vibratory screening machine with two screening surfaces having assemblies with concave screening surfaces Installed thereon where the screen assemblies Include pyramidal shaped and fiat subgrids, according to an exemplary embodiment of the présent Invention.

Agure 31 Is a front view of a vibratory screening machine with a single screen surface having an assembly with a concave screening surface installed thereon where the screen assembly Includes pyramidal shaped and fiat subgrids, according to an exemplary embodiment of the présent Invention.

Figure 32 is a front view of a vibratory screening machine with two screening surfaces having preformed screen assemblies with fiat screening surfaces installed thereon where the screen assemblies inciude pyramidal shaped and fiat subgrids, according to an exemplary embodiment of the présent Invention.

Figure 33 is a front view of a vibratory screening machine with a single screening surface having a preformed screen assembly with a fiat screening surface Installed thereon where the screen assembly includes pyramidal shaped and fiat subgrids, according to an exemplary embodiment of the présent invention.

Figure 34 Is an Isométrie view of the end subgrid shown In Figure 3 having a single screen element partially attached thereto, according to an exemplary embodiment of the présent invention.

Figure 35 is an enlarged view of break out Section E of the end subgrid shown in Figure 34.

Figure 36 is an Isométrie view of a screen assembly having pyramidal shaped subgrids in a portion ofthe screen assembly, according to an exemplary embodiment of the présent invention.

Figure 37 Is a flow chart of a screen assembly fabrication, according to an exemplary embodiment of the présent Invention.

Figure 38 Is a flow chart of a screen assembly fabrication, according to an exemplary embodiment of the présent Invention.

Figure 39 an Isométrie view of a vibratory screening machine having a single screen assembly with a fiat screening surface installed thereon with a portion of the vibratory machine eut away showing the screen assembly, according to an exemplary embodiment of the présent invention.

Figure 40 is an Isométrie top view of an individual screen element, according to an exemplary embodiment of the présent Invention.

Figure 40A is an isométrie top view of a screen element pyramid, according to an exemplary embodiment of the présent invention.

Figure 40B is an Isométrie top view of four of the screen element pyramids shown in Figure 40A.

Figure 40C Is an isométrie top view of an Inverted screen element pyramid, according to an exemplary embodiment of the présent invention.

Figure 40D is a front view of the screen element shown In Figure 40C.

Figure 40E Is an isométrie top view of a screen element structure, according to an exemplary embodiment of the présent Invention.

Figure 40F is a front view of the screen element structure shown In Figure 40E.

Figures 41 to 43 are front cross-sectional profile views of screen éléments, according to exemplary embodiments of the présent Invention.

Figure 44 is an isométrie top view of a prescreening structure with prescreen assemblies according to an exemplary embodiment of the présent invention.

Figure 44A is an isométrie top view of the prescreen assembly shown in Figure 44, according to an exemplary embodiment of the présent Invention.

DETAILED DESCRIPTION

Like reference characters dénoté iike parts in several drawings.

Embodiments of the présent invention provide a screen assembly that includes injection molded screen éléments that are mated to a subgrid. Multiple subgrids are securely fastened to each other to form the vibratory screen assembly, which has a continuous screening surface and is configured for use on a vibratory screening machine. The entire screen assembly structure is configured to withstand rigorous loading conditions encountered when meunted and operated on a vibratory screening machine. Injection molded screen éléments provide for many advantages In screen assembly manufacturing and vibratory screening applications, ln certain embodiments of the présent Invention, screen éléments are Injection molded using a thermoplastic material.

Embodiments of the présent invention provide injection molded screen éléments that are of a practical size and configuration for manufacture of vibratory screen assemblies and for use In vibratory screening applications. Several Important considérations hâve been taken into account In the configuration of Individual screen éléments. Screen éléments are provided that: are of an optimal size (large enough for efficient assembly of a complote screen assembly structure yet small enough to Injection mold (micromold ln certain embodiments) extremely small structures forming screening openings while avolding freezing (Le., material hardening In a mold before completely filling the mold)); hâve optimal open screening area (the structures forming the openings and supportlng the openings are of a minimal size to Increase the overall open area used for screening while maintaining, In certain embodiments, very small screening openings necessary to property separate matériels to a specified standard); hâve durabiiity and strength, can operate In a variety of température ranges; are chemically résistant; are structural stable; are highly versatile in screen assembly manufacturing processes; and are configurable in customizable configurations for spécifie applications.

Embodiments of the présent invention provide screen éléments that are fabricated using extremely précisé Injection molding. The larger the screen element the easier II is to assemble a complote vibratory screening assembly. Simply put, the fewer pièces there are to put together.

However, the larger the screen element the more difficult it is to injection mold extremely small structures, Le. the structures forming the screening openings. It Is important to minimize the size of the structures forming the screening openings so as to maximize the number of screening openings on an Individual screen element and thereby optimlze the open screening area for the screening element and thus the overall screen assembly. ln certain embodiments, screen éléments are provided that are large enough (e.g., one inch by one Inch, one Inch by two Inches, two Inches by three Inches, etc.) to make It practical to assemble a complété screen assembly screening surface (e.g., two feet by three feet, three feet by four feet, etc.). The reiatively small size (e.g., one Inch by one Inch, one inch by two Inches, two inches by three Inches, etc.) Is fairiy large when micromolding extremely small structural members (e.g., structural members as small as 43 microns). The larger the size of the overall screen element and the smaller the size of the individual structural members forming the screening openings the more prone the Injection molding process Is to errors such as freezing. Thus, the size of the screen éléments must be practical for screen assembly manufacture while at the same time small enough to eliminate problème such as freezing when micromolding extremely small structures. Slzes of screening éléments may very based on the material being Injection moided, the size of the screening openings required and the overall open screening area desired.

Open screening area is a criticai feature of vibratory screen assemblies. The average usable open screening area (I.e., actual open area after taking Into account the structura! stee! of support members and bonding materials) for traditiona! 100 mesh to 200 mesh wire screen assemblies may be ln the range of 16%. Spécifie embodiments of the présent Invention (e.g., screening assemblies with constructions described herein and having 100 mesh to 200 mesh screen openings) provide screen assemblies ln the same range having a similar actual open screening areas. Traditiona! screens, however, blind fairiy quickiy in the field which results in the actual opening screening area being reduced fairiy quickiy. It is not uncommon for traditiona! meta! screens to blind within the first 24 hours of use and to hâve the actual open screening area reduced by 50%. Traditlonal wire assemblies also frequently fail as a resuit of wires being subjected to vibratory forces which place bending loads of the wires. Injection moided screen assemblies, according to embodiments of the présent invention, ln contrast, are not subject to extensive biinding (thereby maintaining a reiatively constant actual open screening area) and rarely fail because of the structural stability and configuration of the screen assembly, including the screen éléments and subgrid structures, ln fact, screen assemblies according to embodiments of the présent Invention hâve extremely long lives and may last for long periods of time under heavlng loading. Screen assemblies according to the présent invention hâve been tested for months under rfgorous conditions with out failure or biinding whereas traditlonal wire assemblies were tested under the same conditions and blinded and failed within days. As more fully discussed herein, traditlonal thermoset type assemblies could not be used ln such applications.

In embodiments of the présent Invention a thermoplastic Is used to Injection mold screen éléments. As opposed to thermoset type polymers, which frequently Include liquid materials that chemically read and cure under température, use of thermoplastics Is often simpler and may be provided, e.g., by melting a homogeneous material (often In the form of solid pellets) and then Injedion molding the meited material. Not only are the physical properties of thermoplastics optimal for vibratory screening applications but the use of thermoplastic liquide provides for easier manufacturing processes, espedally when mlcromolding parts as described herein. The use of thermoplastic materials in the présent invention provides for excellent flexure and bending fatigue strength and Is idéal for parts subjeded to Intermittent heavy loading or constant heavy loading as Is encountered with vibratory screens used on vibratory screening machines. Because vibratory screening machines are subjed to motion, the iow coefficient of fridion of the thermoplastic injection moided materials provides for optimal wear charaderistics. Indeed, the wear résistance of certain thermoplastics is superior to many metals. Further, use of thermoplastics as described herein provides an optimal material when making snap-fits due to Its toughness and élongation charaderistics. The use of thermoplastics In embodiments of the présent Invention also provides for résistance to stress cracking, aging and extreme weathering. The heat defledton température of thermoplastics is in the range of 200*F. With the addition of glass fibers, this wiii Increase to approximately 250’F to approximately 300’F or greater and increase rigidity, as measured by Flexural Modulus, from approximately 400,000 PSI to over approximately 1,000,000 PSI. All of these properties are Idéal for the environment encountered when using vibratory screens on vibratory screening machines under the demanding conditions encounter In the field.

Figure 1 illustrâtes a screen assembly 10 for use with vibratory screening machines. Screen assembly 10 Is shown having multiple screen éléments 16 (See, e.g., Figures 2 and 2A-2D) mounted on subgrid strudures. The subgrid strudures indude multiple independent end subgrid unlts 14 (See, e.g., Figure 3) and multiple independent center subgrid units 18 (See, e.g., Figure 4) that are secured together to form a grid framework having grid openings 50. Each screen element 16 spans four grid openings 50. Although screen element 16 is shown as a unit covering four grid openings, screen éléments may be provided In langer or smaller slzed units. For example, a screen element may be provided that is approximately one-fourth the size of screen element 16 such that It would span a slngie grid opening 50. Altematively, a screen element may be provided that Is approximately twice the size of screen element 16 such that It would span all elght grid openings of subgrid 14 or 18. Subgrids may also be provided In different sizes. For example, subgrid units may be provided that hâve two grid openings per unit or one large subgrid may be provided for the overall structure, I.e., a single subgrid structure for the entire screen assembly. In Figure 1, multiple Independent subgrids 14 and 18 are secured together to form the screen assembly 10. Screen assembly 10 has a continuous screen assembly screening surface 11 that Indudes multiple screen element screening surfaces 13. Each screen element 16 Is a single thermoplastic Injection molded piece.

Figure 1A Is an enlarged view of a portion of the screen assembly 10 having multiple end subgrids 14 and center subgrids 18. As discussed below, the end subgrids 14 and center subgrids 18 may be secured together to form the screen assembly. Screen éléments 16 are shown attached to the end subgrids 14 and center subgrids 18. The size of the screen assembly may be altered by attaching more or less subgrids together to form the screen assembly. When installed ln a vibratory screening machine, material may be fed onto the screen assembly 10. See, e.g., Figures 12, 12A, 12B, 13, 13A, 14 and 15. Material smalier than the screen openings of the screen element 16, passes through the openings In screening element 16 and through the grid openings 50 thereby separating the material from that which Is too blg to pass through the screen openings of the screen éléments 16.

Figure 1B shows a bottom view of the screen assembly 10 such that the grid openings 50 may be seen below the screen éléments. Binder bars 12 are attached to sides of the grid framework. Binder bars 12 may be attached to lock subassembiies together creatlng the grid framework. Binder bars 12 may include fasteners that attach to fasteners on side members 38 of subgrid units (14 and 18) or fasteners on base member 64 of pyramidal subgrid units (58 and 60). Binder bars 12 may be provided to Increase the stability of the grid framework and may distribute compression loads if the screen assembly Is mounted to a vibratory screening machine using compression, e.g., using compression assemblies as described in U.S. Patent No. 7,578,394 and U.S. Patent Application No. 12/460,200. Binder bars may aiso be provided that include U-shaped members or finger receiving apertures, for undermount or overmount tensioning onto a vibratory screening machine, e.g., see mounting structures described ln U.S. Patent Nos. 5,332,101 and 6,669,027. The screen éléments and subgrids are securely attached together, as described herein, such that, even under tensioning, the screen assembly screening surface and screen assembly malntaln their structural integrity.

The screen assembly shown In Figure 1 Is slightly concave, I.e., the bottom and top surfaces of the screen assembly hâve a slight curvature. Subgrids 14 and 18 are fabricated such that when they are assembled together this predetermined curvature is achieved. Altematively, a screen assembly may be fiat or convex (see, e.g., Figures 19 and 20). As shown in Figures 12, 12A, 13, and 13A, screen assembly 10 may be installed upon a vibratory screening machine having one or more screening surfaces, ln one embodiment, screen assembly 10 may be Installed upon a vibratory screening machine by pladng screen assembly 10 on the vibratory screening machine such that the binder bars contact end or side members of the vibratory screening machine.

Compression force Is then applied to binder bar 12. Binder bars 12 distribute the load from the compression force to the screen assembly. The screen assembly 10 may be configured such that it flexes and deforms Into a predetermined concave shape when compression force Is applied to binder bar 12. The amount of deformation and range of concavity may vary according to use, compression forced applied, and shape of the bed support of the vibratory screening machine. Compressing screen assembly 10 Into a concave shape when installed in a vibratory screening machine provides many benefits, e.g., easy and simple installation and removal, capturing and centering of materiais to be screened, etc. Further benefits are enumerated in U.S. Patent No. 7,578,394. Centering of material streams on screen assembly 10 prevents the material from exitlng the screening surface and potentially contamlnating previously segregated materiais and/or creating maintenance concems. For larger material flow volumes, screen assembly 10 may be placed in greater compression, thereby increasing the amount of arc of the screen assembly 10. The greater the amount of arc In screen assembly 10 allows for greater retaining capability of material by screen assembly 10 and prévention of over spilling of material off edges of the screen assembly 10. Screen assembly 10 may also be configured to deform into a convex shape under compression or remain substantialiy fiat under compression or damplng. Incorporating binder bars 12 into the screen assembly 10 allows for a compression load from a vibratory screening machine to be distributed across the screen assembly 10. Screen assembly 10 may include guide notches In the binder bars 12 to help guide the screen assembly 10 Into place when installed upon a vibratory screening machine having guides. Altematively, the screen assembly may be Installed upon a vibratory screening machine without binder bars 12. In the alternative embodiment, guide notches may be Induded In subgrid units. US Patent Application No. 12/460,200 Is Incorporated herein by référencé and any embodiments disdosed thereln may be Incorporated into embodiments of the présent invention described herein.

Figure 2 shows a screen element 16 having substantialiy parallel screen element end portions 20 and substantialiy parallel screen element side portions 22 that are substantialiy perpendicular to the screen element end portions 20. The screen element screening surface 13 Indudes surface éléments 84 runnlng parallel to the screen element end portions 20 and forming screening openings 86, See Figure 2D. Surface éléments 84 hâve a thickness T, which may vary dependlng on the screening application and configuration of the screening openings 86. T may be, e.g., approxlmately 43 microns to approximately 100 microns depending on the open screening area desired and the width W of screening openings 86. The screening openings 86 are elongated s lots having a length L and a width W, which may be varied for a chosen configuration. The width may be a distance of approxlmately 43 microns to approxlmately 2000 microns between Inner surfaces of each screen surface element 84. The screening openings are not required to be rectangular but may be thermoplastic injection molded to any shape suitable to a particular screening application, including approximately square, clrcular and/or oval. For increased stability, the screen surface éléments 84 may include integra! fiber materials which may run substantiaily parallel to end portions 20. The fiber may be an aramid fiber (or individual filaments thereof), a naturally occurring fiber or other material having a relatively high tensile strength. U.S. Patent No. 4,819,809 and U.S. Patent Application No. 12/763,046 are incorporated herein by reference and, as appropriate, the embodiments disclosed therein may be incorporated into the screen assemblies disclosed herein.

The screen element 16 may include attachment apertures 24 configured such that elongated attachment members 44 of a subgrid may pass through the attachment apertures 24. The attachment apertures 24 may Include a tapered bore that may be filled when a portion of the elongated attachment member 44 above the screening element screening surface is melted fastening screen element 16 to the subgrid. Altematively, the attachment apertures 24 may be configured without a tapered bore allowlng formation of a bead on the screening element screening surface when a portion of an elongated attachment member 44 above a screening element screening surface is melted fastening the screen element to the subgrid. Screen element 16 may be a single thermoplastic injection molded piece. Screen element 16 may also be multiple thermoplastic Injection molded pièces, each configured to span one or more grid openings. Utilizing small thermoplastic Injection molded screen éléments 16, which are attached to a grid framework as described herein, provides for substantiel advantages over prior screen assemblies. Thermoplastic injection molding screen éléments 16 allow for screening openings 86 to hâve wldths W as small as approximately 43 microns. This allows for précisé and effective screening. Arranging the screen éléments 16 on subgrids, which may also be thermoplastic injection molded, allows for easy construction of complété screen assemblies with very fine screening openings. Arranging the screen éléments 16 on subgrids also allows for substantiel variations in overall size and/or configuration of the screen assembly 10, which may be varied by including more or less subgrids or subgrids having different shapes. Moreover, a screen assembly may be constructed having a variety of screening opening slzes or a gradient of screening opening sizes simply by Incorporatlng screen éléments 16 with the different size screening openings onto subgrids and jolning the subgrids in the desired configuration.

Figure 2B and Figure 2C show a bottom of the screen eiement 16 having a first screen element support member 28 extending between the end portions 20 and being substantiaily perpendicular to the end portions 20. FIG 2B also shows a second screen eiement support member 30 orthogonal to the first screen eiement support member 28 extending between the side edge portions 22 being approximately paraliel to the end portions 20 and substantiaily perpendicular to the side portions 22. The screen element may further Include a first sériés reinforcement members 32 substantially parallei to the side edge portions 22 and a second sériés of reinforcement members 34 substantially parallei to the end portions 20. The end portions 20, the side edge portions 22, the first screen element support member 28, the second screen element support member 30, the first sériés reinforcement members 32, and the second sériés of reinforcement members 34 structurally stabilize the screen surface éléments 84 and screening openings 86 during different loadings, Including distribution of a compression force and/or vibratory loading conditions.

Figure 3 and Figure 3A iliustrate an end subgrid 14 unit. The end subgrid unit 14 Indudes parallei subgrid end members 36 and parallei subgrid side members 38 substantially perpendicular to the subgrid end members 36. The end subgrid unit 14 has fasteners along one subgrid end member 36 and along the subgrid side members 38. The fasteners may be clips 42 and dip apedures 40 such that multiple subgrid units 14 may be securely attached together. The subgrid units may be secured together along their respedive side members 38 by passing the dip 42 Into the clip aperture 40 until extended members of the dip 42 extend beyond dip aperture 40 and subgrid side member 38. As the dip 42 Is pushed Into the clip aperture 40, the dîp's extended members will be forced together until a clipping portion of each extended member Is beyond the subgrid side member 38 allowing the clipping pariions to engage an Interior portion of the subgrid side member 38. When the dippîng portions are engaged Into the clip aperture, subgrid side members of two Independent subgrids will be side by side and secured together. The subgrids may be separated by applying a force to the dip’s extended members such that the extended members are moved together allowing for the clipping portions to pass out of the dip aperture. Alternative^, the clips 42 and dip apertures 40 may be used to secure subgrid end member 36 to a subgrid end member of another subgrid, such as a center subgrid (Fig. 4). The end subgrid may hâve a subgrid end member 36 that does not hâve any fasteners. Aithough the fasteners shown In drawings are dips and dip apertures, alternative fasters and alternative forms of dips and apertures may be used, Induding other mechanical arrangements, adhesives, etc.

Constructing the grid framework from subgrids, which may be substantially rlgid, créâtes a strong and durable grid framework and screen assembly 10. Screen assembly 10 is construded so that it can withstand heavy loading without damage to the screening surface and supporting structure. For example, the pyramidal shaped grid frameworks shown in Figures 22 and 23 provide a very strong pyramld base framework that supports Individuai screen éléments capable of very fine screening, having screening openings as small as 43 microns. Unlike the pyramidal screen assembly embodiment of the présent invention described herein, exlstlng corrugated or pyramld type wire mesh screen assemblies are highly susceptible to damage and/or deformation under heavy ioading. Thus, unlike current screens, the présent Invention provides for screen assernblies having very small and very précisé screening openings whiie simultaneously providing substantlal structurai stability and résistance to damage thereby maintainlng précision screening under a variety of load burdens. Constructing the grid framework from subgrids also allows for substantial variation In the size, shape, and/or configuration of the screen assembly by slmply altering the number and/or type of subgrids used to construct the grid framework.

End subgrid unit 14 Includes a first subgrid support member 46 runnlng parallel to subgrid side members 38 and a second subgrid support member 48 orthogonal to the first subgrid support member 46 and perpendicuiar to the subgrid side members 38. Elongated attachment members 44 may be configured such that they mate with the screen element attachment apertures 24. Screen element 16 may be secured to the subgrid 14 via mating the elongated attachment members 44 with screen element attachment apertures 24. A portion of elongated attachment member 44 may extend slightly above the screen element screening surface when the screen element 16 Is attached to the end subgrid 14. The screen element attachment apertures 24 may include a tapered bore such that a portion of the eiongated attachment members 44 extending above the screen element screening surface may be melted and fill the tapered bore. Altematively, screen element attachment apertures 24 may be without a tapered bore and the portion of the elongated attachment members extending above the screening surface of the screening element 16 may be configured to form a bead on the screening surface when melted. See Figures 34 and 35. Once attached, the screen element 16 will span at ieast one grid opening 50. Materials passlng through the screening openings 86 will pass through grid opening 50. The arrangement of elongated attachment members 44 and the corresponding arrangement of screen element attachment apertures 24 provide a guide for attachment of screen éléments 16 to subgrids slmplifying assembly of subgrids. The elongated attachment members 44 pass through the screen element attachment apertures 24 gulding the screen element into correct placement on the surface of the subgrid. Attachment via elongated attachment members 44 and screen element attachment apertures 24 further provides a secure attachment to the subgrid and strengthens the screening surface of the screen assembly 10.

Figure 4 shows a center subgrid 18. As shown in Figure 1 and Figure 1A, the center subgrid 18 may be incorporated Into a screen assembly. The center subgrid 18 has clips 42 and clip apertures 40 on both subgrid end members 36. The end subgrid 14 has clips 42 and clip apertures 40 on only one of two subgrid side members 36. Center subgrids 18 may be secured to other subgrids on each of Its subgrid end members and subgrid side members.

Figure 5 shows a top view of binder bar 12. Figure 5A shows a bottom view of binder bar 12. Binder bars 12 include clips 42 and clip apertures 40 such that binder bar 12 may be clipped to 28 a side of an assembly of screen panels (see Figure 9). As with subgrids, fasteners on the binder bar 12 are shown as clips and dip apertures but other fasteners may be utilized to engage fasteners of the subgrids. Handles may be attached to binder bars 12 (see, e.g., Figure 7) which may slmplify transportation and Installation of a screen assembly. Tags and/or labels may also be attached to binder bars. As discussed above, binder bars 12 may increase the stability of the grid framework and may distribute compression loads of a vibratory screening machine if the screen assembly Is placed under compression as shown In U.S. Patent No. 7,578,394 and U.S. Patent Application No. 12/460,200.

The screening members, screening assemblies and parts thereof, Including connecting members/fasteners as described herein, may Include nanomaterial dispersed thereln for improved strength, durablllty and other benefits associated with the use of a particular nanomaterial or combination of different nanomaterials. Any suitable nanomaterial may be used, Including, but not limited to nanotubes, nanofibers and/or elastomeric nanocomposites. The nanomaterial may be dispersed in the screening members and screening assemblies and parts thereof In varying percentages, depending on the desired properties of the end product. For exampie, spedfic percentages may be Incorporated to Increase member strength or to make a screening surface wear résistant. Use of a thermoplastic Injection molded material having nanomaterials dispersed thereln may provide for increased strength while using less material. Thus, structural members, Inciude subgrid framework supports and screen element supporting members may be made smaller and stronger and/or lighter. This Is particulariy bénéficiai when fabricatlng relatlvely small Individual components that are built Into a complété screen assembly. Aiso, instead of produdng individual subgrids that dip together, one large grid structure having nanomaterials dispersed thereln, may be fabricated that Is relatlvely light and strong. Individual screen éléments, with or without nanomaterials, may then be attached to the single complété grid framework structure. Use of nanomaterials in a screen element will provide increased strength while redudng the weight and size of the element. This may be espedaily helpful when Injection moiding screen éléments having extremely small openings as the openings are supported by the surrounding materials/members. Another advantage to Incorporatlng nanomaterials into the screen éléments Is an improved screening surface that Is durable and résistant to wear. Screen surfaces tend to wear out through heavy use and exposure to abrasive materials and use of a thermoplastic and/or a thermoplastic having abrasive résistant nanomaterials, provides for a screening surface with a long life.

Figure 6 shows a subassembly 15 of a row of subgrid units. Figure 6A Is an exploded view of the subassembly In Figure 6 showing Individual subgrids and direction of attachment to each other. The subassembly Indudes two end subgrid units 14 and three center subgrid units 18. The end subgrid units 14 form the ends of the subassembly while the center subgrid units 18 are used to Joln the two end subgrid units 14 via connections between the clips 42 and clip apertures 40. The subgrid units shown In Figure 6 are shown with attached screen éléments 16. By fabricating the screen assembly from subgrids and Into the subassembly, each subgrid may be constructed to a chosen spécification and the screen assembly may be constructed from multiple subgrids In a configuration required for the screening application. The screen assembly may be quickly and simply assembled and will hâve précisé screening capabilities and substantiel stability under load pressures. Because of the structure configuration of the grid framework and screen éléments 16, the configuration of multiple individual screen éléments forming the screening surface of the screen assembly 10 and the fact that the screen éléments 16 are thermoplastic injection molded, the openings in screen éléments 16 are relatively stable and maintaln their opening sizes for optimal screening under various loading conditions, Including compression loads and concavity deflections and tensloning.

Figure 7 shows a screen assembly 10 with binder bars 12 having handles attached to the binder bars 12. The screen assembly is made up of multiple subgrid units secured to each other. The subgrid units hâve screen éléments 16 attached to their top surfaces. Figure 7A Is a crosssection of Section A-A of Figure 7 showing individual subgrids secured to screen éléments forming a screening surface. As reflected In Figure 7A, the subgrids may hâve subgrid support members 48 configured such that screen assembly has a slightly concave shape when the subgrid support members 48 are fastened to each other via clips 42 and clip apertures 40. Because the screen assembly Is constructed with a slightly concave shape it may be configured to deform to a desired concavity upon application of a compression load without having to guide the screen assembly into a concave shape. Altematively, the subgrids may be configured to create a slightly convex screen assembly or a substantially fiat screen assembly.

Figure 8 Is a top Isométrie view of a screen assembly partialiy covered with screen éléments 16. This figure shows end subgrid units 14 and center subgrid units 18 secured to form a screen assembly. The screening surface may be completed by attaching screen éléments 16 to the uncovered subgrid units shown in the figure. Screen éléments 16 may be attached to individuel subgrids prior to construction of the grid framework or attached to subgrids after subgrids hâve been fastened to each other into the grid framework.

Figure 9 is an exploded Isométrie view of the screen assembly shown In Figure 1. This figure shows eleven subassemblies being secured to each other via clips and clip apertures along subgrid end members of subgrid units in each subassembly. Each subassembly has two end subgrid units 14 and three center subgrid units 18. Binder bars 12 are clipped at each side of the assembly. Different size screen assemblées may be created using different numbers of subassemblies or different numbers of center subgrid units in each subassembly. An assembled 30 screen assembiy has a continuous screen assembiy screening surface made up of multiple screen element screening surfaces.

Figures 10 and 10A Illustrate attachment of screen éléments 16 to end subgrid unit 14, according to an exemplary embodiment of the présent invention. Screen éléments 16 may be aligned with end subgrid unit 14 via the elongated attachment members 44 and the screen element attachment apertures 24 such that the elongated attachment members 44 pass through the screen element attachment apertures 24 and extend slightiy beyond the screen element screening surface. The elongated attachment members 44 may be melted to fill the tapered bores of the screen element attachment apertures 24 or, altemativeiy, to form beads upon the screen element screening surface, securing the screen element 16 to the subgrid unit 14. Attachment via elongated attachment members 44 and screen element attachment apertures 24 ls only one embodiment of the présent invention. Altemativeiy, screen element 16 may be secured to end subgrid unit 14 via adhesive, fasteners and fastener apertures, etc. Although shown having two screen éléments for each subgrid, the présent invention Includes altemate configurations of one screen element per subgrid, multiple screen éléments per subgrid, one screen element per subgrid opening, or having a single screen element cover multiple subgrids. The end subgrid 14 may be substantially rigld and may be formed as a single thermoplastic injection moided piece.

Figure 10B is a top view of the end subgrid unit shown in Figure 10A with screen éléments 16 secured to the end subgrid. Figure 10C is an enlarged cross-section of Section B-B of the end subgrid unit in Figure 10B. Screen eiement 16 is placed upon the end subgrid unit such that elongated attachment member 44 passes through the attachment aperture and beyond a screening surface of the screen element. The portion of the elongated attachment member 44 passing through the attachment aperture and beyond the screening surface of the screen element may be melted to attach the screen element 16 to the end subgrid unit as described above.

Figure 11 and Figure 11A illustrate attachment of screen éléments 16 to center subgrid unit 18, according to an exemplary embodiment of the présent invention. Screen éléments 16 may be aligned with center subgrid unit 18 via the elongated attachment members 44 and the screen eiement attachment apertures 24 such that the elongated attachment members 44 pass through the screen element attachment apertures 24 and extend slightiy beyond the screen element screening surface. The elongated attachment members 44 may be melted to fiil the tapered bores of the screen eiement attachment apertures 24 or, altemativeiy, to form beads upon the screen element screening surface, securing the screen element 16 to center subgrid unit 18. Attachment via elongated attachment members 44 and screen element attachment apertures 24 is only one embodiment of the présent invention. Altemativeiy, screen element 16 may be secured to center subgrid unit 14 via adhesive, fasteners and fastener apertures, etc. Although shown having two 31 screen éléments for each subgrid, the présent Invention Inciudes altemate configurations of one screen element per subgrid, one screen element per subgrid opening, multiple screen éléments per subgrid, or having a single screen element cover multiple subgrid units. The center subgrid unit 18 may be substantially rigid and may be a single thermopiastic injection molded piece.

Figures 12 and 12A show screen assemblies 10 installed on a vibratory screening machine having two screening surfaces. The vibratory screening machine may hâve compression assemblies on side members of the vibratory screening machine, as shown in U.S. Patent No. 7,578,394. A compression force may be applied to a binder bar or a side member of the screen assembly such that the screen assembly deflects downward Into a concave shape. A bottom side of the screen assembly may mate with a screen assembly mating surface of the vibratory screening machine as shown In U.S. Patent No. 7,578,394 and U.S. Patent Application No. 12/460,200. The vibratory screening machine may include a center wall member configured to receive a binder bar of a side member of the screen assembly opposite of the side member of the screen assembly receiving compression. The center wall member may be angled such that a compression force against the screen assembly deflects the screen assembly downward. The screen assembly may be installed in the vibratory screening machine such that It is configured to receive material for screening. The screen assembly may include guide notches configured to mate with guides of the vibratory screening machine such that the screen assembly may be guided into place during Installation and may include guide assembly configurations as shown in U.S. Patent Application No. 12/460,200.

Figure 12B Is a front view of the vibratory screening machine shown in Figure 12. Figure 12B shows screen assemblies 10 installed upon the vibratory screening machine with compression applied to deflect the screen assemblies downward Into a concave shape. Altematively, the screen assembly may be preformed In a predetermlned concave shape without compression force.

Figures 13 and 13A show installations of screen assembly 10 In a vibratory screening machine having a single screening surface. The vibratory screening machine may hâve a compression assembly on a side member of the vibratory screening machine. Screen assembly 10 may be placed into the vibratory screening machine as shown. A compression force may be applied to a binder bar or side member of the screen assembly such that the screen assembly deflects downward Into a concave shape. A bottom side of the screen assembly may mate with a screen assembly mating surface of the vibratory screening machine as shown In U.S. Patent No. 7,578,394 and U.S. Patent Application No. 12/460,200. The vibratory screening machine may Include a side member wall opposite of the compression assembly configured to receive a binder bar or a side member of the screen assembly. The side member wall may be angled such that a compression force against the screen assembly deflects the screen assembly downward. The 32 screen assembly may be Installed In the vibratory screening machine such that it Is configured to receive material for screening. The screen assembly may Indude guide notches configured to mate with guides of the vibratory screening machine such that the screen assembly may be guided Into place during Installation.

Figure 14 Is a front view of screen assemblies 52 Installed upon a vibratory screening machine having two screening surfaces, according to an exemplary embodiment of the présent invention. Screen assembly 52 1s an alternats embodiment where the screen assembly has been preformed to fit Into the vibratory screening machine without applying a load to the screen assembly, I.e., screen assembly 52 Includes a bottom portion 52A that 1s formed such that It mates with a bed 83 of the vibratory screening machine. The bottom portion 52A may be formed Integraily with screen assembly 52 or maybe a separate plece. Screen assembly 52 includes similar features as screen assembly 10, Induding subgrids and screen éléments but also indudes bottom portion 52A that allows It to fit onto bed 83 without being compressed Into a concave shape. A screening surface of screen assembly 52 may be substantially fiat, concave or convex. Screen assembly 52 may be held Into place by applying a compression force to a slde member of screen assembly 52. A bottom portion of screen assembly 52 may be preformed to mate with any type of mating surface of a vibratory screening machine.

Figure 15 Is a front view of screen assembly 53 Installed upon a vibratory screening machine having a single screening surface, according to an exemplary embodiment of the présent Invention. Screen assembly 53 has similar features of screen assembly 52 described above, Induding a bottom portion 53A that Is formed such that It mates with a bed 87 of the vibratory screening machine.

Figure 10 shows an end support frame subassembly and Figure 16A shows an exploded view of the end support frame subassembly shown In Figure 16. The end support frame subassembly shown In Figure 16 Incorporâtes eleven end subgrid units 14. Alternats configurations having more or less end subgrid units may be utilized. The end subgrid units 14 are secured to each other via clips 42 and clip apertures 40 along side members of the end subgrid units 14. Figure 16A shows attachment of Individus! end subgrid units such that the end support frame subassembly Is created. As shown, the end support frame subassembly 1s covered In screen éléments 16. Aitemativeiy, the end support frame subassembly may be constructed from end subgrids prior to attachment of screen éléments or partiaily from pre-covered subgrid units and partiaily from uncovered subgrid units.

Figure 17 shows a center support frame assembly and Figure 17A shows an exploded view of the center support frame subassembly shown In Figure 17. The center support frame assembly shown In Figure 17 Incorporâtes eleven center subgrid units 18. Altemate configurations having 33 more or less center subgrid units may be utillzed. The center subgrid units 18 are secured to each other via clips 42 and clip apertures 40 along side members of the center subgrid units 18. Figure 17A shows attachment of individual center subgrid units such that the center support frame subassembly is created. As shown, the center support frame subassembly Is covered in screen éléments 16. Alternatively, the center support frame subassembly may be constructed from center subgrids prior to attachment of screen éléments or partially from pre-covered subgrid units and partially from uncovered subgrid units.

Figure 18 shows an exploded view of a screen assembly having three center support frame subassemblies and two end support frame subassemblies. The support frame assemblies are secured to each other via the clips 42 and clip apertures 40 on the subgrid end members. Each center subgrid unit Is attached to two other subgrid units via end members. End members 36 of end subgrid units having no clips 42 or clip apertures 40 form the end edges of the screen assembly. The screen assembly may be made with more or less center support frames subassemblies or Iarger or smaller frame subassemblies. Binder bars may be added to side edges of the screen assembly. As shown, the screen assembly has screen éléments installed upon the subgrid units prior to assembly. Alternatively, screen éléments 16 may be installed after ali or a portion of assembly.

Figure 19 Illustrâtes an alternative embodiment of the present disdosure where screen assembly 54 is substantially fiat. Screen assembly 54 may be flexible such that It can be deformed Into a concave or convex shape or may be substantially rigld. Screen assembly 54 may be used with a fiat screening surface. See Figure 39. As shown, screen assembly 54 has binder bars 12 attached to side portions of the screen assembly 54. Screen assembly 54 may be configured with the various embodiments of the grid structures and screen éléments described herein.

Figure 20 Illustrâtes an alternative embodiment of the present disdosure wherein screen assembly 56 is convex. Screen assembly 56 may be flexible such that it can be deformed Into a more convex shape or may be substantially rigld. As shown, screen assembly 56 has binder bars 12 attached to side portions of the screen assembly. Screen assembly 56 may be configured with the various embodiments of the grid structures and screen éléments described herein.

Figures 21 and 21A show an alternative embodiment of the present disdosure Incorporating pyramidal shaped subgrid units. A screen assembly Is shown with binder bars 12 attached. The screen assembly incorporâtes center and end subgrid units 14 and 18 and center and end pyramidal shaped subgrid units 58 and 60. By incorporating the pyramidal shaped subgrid units 58 and 60 Into the screen assembly, an increased screening surface may be achieved. Additionally, material being screened may be controlled and directed. The screen assembly may be concave, convex, or fiat The screen assembly may be flexible and may be deformed into a concave or 34 convex shape upon the application of a compression force. The screen assembly may include guide notches capable of mating with guide mating surfaces on a vibratory screening machine. Different configurations of subgrid units and pyramid subgrid units may be employed which may Increase or decrease an amount of screening surface area and flow characteristics of the material being processed. Unlike mesh screens or similar technology, which may Incorporate corrugations or other manipulations to Increase surface area, the screen assembly shown Is supported by the grid framework, which may be substantially rigid and capable of withstanding substantiai ioads without damage or destruction. Under heavy material flows, traditionai screen assemblies with corrugated screening surfaces are frequently flattened or damaged by the weight of the material, thereby Impacting the performance and redudng the screening surface area of such screen assemblies. The screen assemblies disdosed herein are difficult to damage because of the strength of the grid framework, and the benefits of increased surface area provided by incorporating pyramidal shaped subgrids may be malntained under substantiai Ioads.

A pyramidal shaped end subgrid 58 is illustrated in Figure 22 and Figure 22A. Pyramidal shaped end subgrid 58 Includes a first and a second grid framework forming first and second sloped surface grid openings 74. Pyramidal shaped end subgrid 58 Includes a ridge portion 66, subgrid side members/base members 64, and first and second angular surfaces 70 and 72, respectively, that peak at ridge portion 66 and extend downwardly to side member 64. Pyramidal shaped subgrids 58 and 60 hâve triangular end members 62 and triangular middle support members 76. Angles shown for first and second angular surface 70 and 72 are exemplary only. Different angles may be employed to Increase or decrease surface area of screening surface. Pyramidal shaped end subgrid 58 has fasteners along side members 64 and at ieast one triangle end member 62. The fasteners may be clips 42 and clip apertures 40 such that multiple subgrid units 58 may be secured together. Altematively, the clips 42 and clip apertures 40 may be used to secure pyramidal shaped end subgrid 58 to end subgrid 14, center subgrid 18, or pyramidal shaped center subgrid 60. Elongated attachment members 44 may be configured on first and second sloped surfaces 70 and 72 such that they mate with the screen element attachment apertures 24. Screen element 16 may be secured to pyramidal shaped end subgrid 58 via mating elongated attachment members 44 with the screen element attachment apertures 24. A portion of the elongated attachment member 44 may extend slightly above the screen element screening surface when the screen element 16 is attached to pyramidal shaped end subgrid 58. The screen element attachment apertures 24 may include a tapered bore such that a portion of the elongated attachment members 44 extending above the screen element screening surface may be melted and fill the tapered bore. Altematively, the screen element attachment apertures 24 may be without a tapered bore and the portion of the elongated attachment members extending above the screening surface of the screening element 16 may be meited to form a bead on the screening surface. Once attached, screen element 16 may span first 74 and second sloped grid openings. Materials passing through the screening openings 86 wili pass through the first 74 and second grid openings.

A pyramidal shaped center subgrid 60 is illustrated in Figure 23 and Figure 23A. Pyramidal shaped center subgrid 60 includes a first and a second grid framework forming a first and second sloped surface grid opening ,74. Pyramidal shaped center subgrid 60 includes a ridge portion 66, a subgrid side members/base members 64, and first and second angular surfaces 70 and 72 that peak at the ridge portion 66 and extend downwardiy to the side member 64. Pyramidal shaped center subgrid 60 has triangular end members 62 and triangular middle members 76. Angles shown for first and second angular surface 70 and 72 are exemplary only. Different angles may be employed to increase or decrease surface area of screening surface. The pyramidal shaped center subgrid 60 has fasteners along side members 64 and both triangle end members 62. The fasters may be clips 42 and clip apertures 40 such that multiple pyramidal shaped center subgrids 60 may be secured together. Altematively, the clips 42 and clip apertures 40 may be used to secure pyramidal shaped center subgrid 60 to end subgrid 14, center subgrid 18, or pyramidal shaped end subgrid 58. Elongated attachaient members 44 may be configured on first and second sloped surfaces 70 and 72 such that they mate with the screen element attachment apertures 24. Screen element 16 may be secured to pyramidal shaped center subgrid 60 via mating elongated attachment members 44 with the screen element attachment apertures 24. A portion of the elongated attachment member 44 may extend siïghtiy above the screen element screening surface when the screen element 16 is attached to pyramidal shaped center subgrid 60. The screen element attachment apertures 24 may include a tapered bore such that the portion of the elongated attachment members 44 extending above the screen element screening surface may be meited and fill the tapered bore. Altematively, the screen element attachment apertures 24 may be without a tapered bore and the portion of the elongated attachment members extending above the screening surface of the screening element 16 may be meited to form a bead on the screening surface. Once attached, screen element 16 wili span sloped grid opening 74. Materials passing through the screening openings 86 wili pass through the grid opening 74. While pyramld and fiat shaped grid structures are shown, it wili be appreciated that various shaped subgrids and corresponding screen éléments may be fabricated in accordance with the présent disclosure.

Figure 24 shows a subassembly of a row of pyramidal shaped subgrid units. Figure 24A is an exploded view of the subassembly In Figure 24 showing the Indivldual pyramidal shaped subgrids and direction of attachment. The subassembly includes two pyramidal shaped end subgrids 58 and three pyramidal shaped center subgrids 60. The pyramidal shaped end subgrids form ends of the subassembly while pyramidal shaped center subgrids 60 are used to join the two end subgrids 58 via connections between the clips 42 and clip apertures 40. The pyramidal subgrids shown ln Figure 24 are shown with attached screen éléments 16. Aitematlvely, the subassembly may be constructed from subgrids prior to attachment of screen éléments or partially from pre-covered pyramidal shaped subgrid units and partially from uncovered pyramidal shaped subgrid units.

Figures 24B and 24C lllustrate attachment of screen éléments 16 to pyramidal shaped end subgrid 58, according to an exemplary embodiment of the présent Invention. Screen éléments 16 may be aligned with pyramidal shaped end subgrid 58 via elongated attachment members 44 and screen element attachment apertures 24 such that the elongated attachment members 44 pass through the screen element attachment apertures 24 may extend slïghtly beyond the screen element screening surface. The portion of elongated attachment members 44 extending beyond screen element screening surface may be melted to fill tapered bores of the screen element attachment apertures 24 or, alternative^, to form beads upon the screen element screening surface, securing the screen element 16 to pyramidal shaped subgrid 58. Attachment via elongated attachment members 44 and screen element attachment apertures 24 is only one embodiment of the présent Invention. Altemativeiy, screen element 16 may be secured to pyramidal shaped end subgrid 58 via adheslve, fasteners and fastener apertures, etc. Although shown having four screen éléments for each pyramidal shaped end subgrid 58, the présent Invention includes altemate configurations of two screen éléments per pyramidal shaped end subgrid 58, multiple screen éléments per pyramidal shaped end subgrid 58, or having a single screen element cover a sloped surface of multiple pyramidal shaped subgrid units. Pyramidal shaped end subgrid 58 may be substantiaily rigid and may be a single thermoplastic Injection molded piece.

Figures 24D and 24E lllustrate attachment of screen éléments 16 to pyramidal shaped center subgrid 60, according to an exemplary embodiment of the présent Invention. Screen éléments 16 may be aligned with pyramidal shaped center subgrid 60 via elongated attachment members 44 and screen element attachment apertures 24 such that the elongated attachment members 44 may pass through the screen element attachment apertures 24 and may extend slïghtly beyond the screen element screening surface. The portion of the elongated attachment ‘ members 44 extending beyond screen element screening surface may be melted to fill tapered bores of the screen element attachment apertures 24 or, altemativeiy, to form beads upon the screen element screening surface, securing the screen element 16 to pyramidal shaped subgrid unit 60. Attachment via elongated attachment members 44 and screen element attachment apertures 24 Is only one embodiment of the présent Invention. Altemativeiy, screen element 16 may be secured to pyramidal shaped center subgrid 60 via adhesive, fasteners and fastener apertures, etc. Although shown having four screen éléments for each pyramidal shaped center subgrid 60, the présent Invention Includes altemate configurations of two screen éléments per pyramidal shaped center subgrid 60, multiple screen éléments per pyramidal shaped center subgrid 60, or having a single screen element cover a sloped surface of multiple pyramidal shaped subgrids. Pyramidal shaped center subgrid 60 may be substantially rigld and may be a single thermoplastlc injection molded piece. While pyramid and fiat shaped grid structures are shown, it will be appredated that various shaped subgrids and correspondîng screen eiements may be fabricated In accordance with the présent disdosure.

Figure 25 is a top view of a screen assembly 60 having pyramidal shaped subgrids. As shown, the screen assembly 60 Is formed from screen subassemblies attached to each other altematlng from fiat subassemblies to pyramidal shaped subassemblies. Altematively, pyramidal shaped subassemblies may be attached to each other or less or more pyramidal shaped subassemblies may be used. Figure 25A is a cross-section of Section C-C of the screen assembly shown In Figure 25. As shown, the screen assembly has five rows of pyramidal shaped subgrid units and six rows of fiat subgrids, with the rows of fiat subgrid units in between each row of the pyramidal shaped subgrids. Binder bars 12 are attached to the screen assembly. Any combination of fiat subgrid rows and pyramidal shaped subgrid rows may be utilized. Figure 25B is a larger view of the cross-section shown in Figure 25A. In Figure 25B, attachment of each subgrid to another subgrid and/or binder bar 12 is visible via clips and ciip apertures.

Figure 26 is an exploded isométrie view of a screen assembly having pyramidal shaped subgrid units. This figure shows eleven subassemblies being secured to each other via dips and clip apertures along subgrid side members of subgrid units in each subassembly. Each fiat subassembly has two end subgrids 14 and three center subgrids 16. Each pyramidal shaped subassembly has two pyramidal shaped end subgrids 56 and three pyramidal shaped center subgrids 60. Binder bars 12 are fastened at each end of the assembly. Different size screen assemblies may be created using different numbers of subassemblies or different numbers of center subgrid units. Screening surface area may be increased by incorporating more pyramidal shaped subassemblies or decreased by incorporating more fiat assemblies. An assembled screen assembly has a continuous screen assembly screening surface made up of multiple screen element screening surfaces.

Figure 27 shows installation of screen assemblies 60 upon a vibratory screening machine having two screening surfaces. Figure 30 is a front view of the vibratory machine shown in Figure 27. The vibratory screening machine may hâve compression assemblies on side members of the vibratory screening machine. The screen assemblies may be placed into the vibratory screening 38 machine as shown. A compression force may be applied to a side member of the screen assembly such that the screen assembly deflects downward into a concave shape. A bottom side of the screen assembly may mate with a screen assembly mating surface of the vibratory screening machine as shown in U.S. Patent No. 7,578,394 and U.S. Patent Application No. 12/460,200. The vibratory screening machine may include a center wall member configured to receive a side member of the screen assembly opposite of the side member of the screen assembly receiving compression. The center wall member may be angled such that a compression force against the screen assembly deflects the screen assembly downward. The screen assembly may be Installed in the vibratory screening machine such that it is configured to receive material for screening. The screen assembly may include guide notches configured to mate with guides of the vibratory screening machine such that the screen assembly may be guided Into place during Installation.

Figure 28 shows an isométrie view of a screen assembly having pyramidal shaped subgrids where screen éléments hâve not been attached. The screen assembly shown in Figure 28 is slightly concave, however, the screen assembly may be more concave, convex or fiat. The screen assembly may be made from multiple subassemblies, which may be any combination of fiat subassemblies and pyramidal shaped subassemblies. As shown, eleven subassemblies are included, however, more or less subassemblies may be included. The screen assembly Is shown without screen éléments 16. The subgrids may be assembled together before or after attachment of screen éléments to subgrids or any combination of subgrids having attached screen éléments and subgrids without screen éléments may be fastened together. Figure 29 shows the screen assembly of Figure 28 partially covered ln screen éléments. Pyramidal shaped subassemblies Include pyramidal shaped end subgrids 58 and pyramidal shaped center subgrids 60. Fiat subassemblies Include fiat end subgrids 14 and fiat center subgrids 18. The subgrid units may be secured to each other via clips and dip apertures.

Figure 31 shows installation of screen assembly 81 In a vibratory screening machine having a single screening surface, according to an exemplary embodiment of the présent Invention. Screen assembly 81 Is similar ln configuration to screen assembly 80 but includes additional pyramid and fiat assemblies. The vibratory screening machine may hâve a compression assembly on a side member of the vibratory screening machine. Screen assembly 81 may be placed into the vibratory screening machine as shown. A compression force may be applled to a side member of screen assembly 81 such that screen assembly 81 deflects downward into a concave shape. A bottom side of the screen assembly may mate with a screen assembly mating surface of the vibratory screening machine as shown in U.S. Patent No. 7,578,394 and U.S. Patent Application No. 12/460,200. The vibratory screening machine may Include a side member wall opposite of the compression assembly configured to receive a side member of the screen assembly. The side member wall may be angled such that a compression force against the screen assembly deflects the screen assembly downward. The screen assembly may be Installed ln the vibratory screening machine such that It is configured to receive material for screening. The screen assembly may Include guide notches configured to mate with guides of the vibratory screening machine such that the screen assembly may be guided into place during Installation.

Figure 32 Is a front view of screen assemblies 82 installed upon a vibratory screening machine having two screening surfaces, according to an exemplary embodiment of the présent invention. Screen assembly 82 Is an altemate embodiment where the screen assembly has been preformed to fit Into the vibratory screening machine without applying a ioad to the screen assembly, I.e., screen assembly 82 includes a bottom portion 82A that Is formed such that it mates with a bed 83 of the vibratory screening machine. The bottom portion 82A may be formed integraliy with screen assembly 82 or It may be a separate piece. Screen assembly 82 includes similar features as screen assembly 80, including subgrids and screen éléments but also Indudes bottom portion 82A that allows It to fit onto bed 83 without being compressed Into a concave shape. A screening surface of screen assembly 82 may be substantially fiat, concave or convex. Screen assembly 82 may be held into place by applying a compression force to a side member of screen assembly 82 or may simply be heid in place. A bottom portion of screen assembly 82 may be preformed to mate with any type of mating surface of a vibratory screening machine.

Figure 33 Is a front view of screen assembly 85 Installed upon a vibratory screening machine having a single screening surface, according to an exemplary embodiment of the présent invention. Screen assembly 85 Is an altemate embodiment where the screen assembly has been preformed to fit into the vibratory screening machine without applying a ioad to the screen assembly i.e., screen assembly 85 Indudes a bottom portion 85A that Is formed such that it mates with a bed 87 of the vibratory screening machine. The bottom portion 85A may be formed Integraliy with screen assembly 85 or It may be a separate piece. Screen assembly 85 indudes similar features as screen assembly 80, Induding subgrids and screen éléments but also Indudes bottom portion 85A that allows it to fit onto bed 87 without being compressed into a concave shape. A screening surface of screen assembly 85 may be substantially fiat, concave or convex. Screen assembly 85 may be held Into place by applying a compression force to a side member of screen assembly 85 or may simply be held in place. A bottom portion of screen assembly 85 may be preformed to mate with any type of mating surface of a vibratory screening machine.

Figure 34 Is an Isométrie view of the end subgrid shown ln Figure 3 having a single screen element partially attached thereto. Figure 35 Is an enlarged view of break out section E of the end subgrid shown ln Figure 34. in Figures 34 and 35, screen element 16 Is partially attached to end subgrid 38. Screen element 16 is aligned with subgrid 38 via elongated attachment members 44 40 and screen element attachment apertures 24 such that the elongated attachment members 44 pass through the screen element attachment apertures 24 and extend slightly beyond the screen element screening surface. As shown along the end edge portion of screen element 16, the portions of the elongated attachment members 44 extending beyond screen element screening surface are melted to form beads upon the screen element screening surface, securing the screen element 16 to end subgrid unit 38.

Figure 36 shows a slightly concave screen assembly 91 having pyramidal shaped subgrids incorporated Into a portion of screen assembly 91 according to an exemplary embodiment of the présent invention. A screening surface of the screen assembly may be substantially fiat, concave or convex. The screen assembly 91 may be configured to deflect to a predetermined shape under a compression force. The screen assembly 91, as shown in Figure 36, Incorporâtes pyramidal shaped subgrids in the portion of the screen assembly installed nearest the inflow of material on the vibratory screening machine. The portion incorporating the pyramidal shaped subgrids ailows for Increased screening surface area and directed material flow. A portion of the screen assembly Installed nearest a discharge end of the vibratory screening machine incorporâtes fiat subgrids. On the fiat portion, an area may be provided such that material may be allowed to dry and/or cake on the screen assembly. Various combinations of fiat and pyramidal subgrids may be included ln the screen assembly depending on the configuration desired and/or the particular screening application. Further, vibratory screening machines that use multiple screen assemblies may hâve Individual screen assemblies with varying configurations designed for use together on spécifie applications. For example, screen assembly 91 may be used with other screen assemblies such that It is positioned near the discharge end of a vibratory screening machine such that It provides for caking and/or drying of a material.

Figure 37 is a flow chart showing steps to fabricate a screen assembly, according to an exemplary embodiment of the présent invention. As shown ln Figure 37, a screen fabricator may receive screen assembly performance spécifications for the screen assembly. The spécifications may include at ieast one of a material requirement, open screening area, capacity and a eut point for a screen assembly. The fabricator may then détermine a screening opening requirement (shape and size) for a screen element as described herein. The fabricator may then détermine a screen configuration (e.g., size of assembly, shape and configuration of screening surface, etc.). For example, the fabricator may hâve the screen éléments arranged ln at least one of a fiat configuration and a nonflat configuration. A fiat configuration may be constructed from center subgrids 18 and end subgrids 14. A nonflat configuration may include at ieast a portion of pyramidal shaped center subgrids 60 and/or pyramidal shaped end subgrids 58. Screen éléments may be injection moided. Subgrid units may also be injection moided but are not required to be

Injection molded. Screen éléments and subgrids may include a nanomateriai, as described herein, dispersed within. After both screen éléments and subgrid units hâve been created, screen éléments may be attached to subgrid units. The screen éléments and subgrids may be attached together using connection materials having a nanomateriai dispersed within. Multiple subgrid units may be attached together forming support frames. Center support frames are formed from center subgrids and end support frames are formed from end subgrids. Pyramidal shaped support frames may be created from pyramidal shaped subgrid units. Support frames may be attached such that center support frames are In a center portion of the screen assembly and end support frames are on an end portion of the screen assembly. Binder bars may be attached to the screen assembly. Different screening surface areas may be accomplished by aitering the number of pyramidal shaped subgrids Incorporated Into the screen assembly. Altematively, screen éléments may be attached to subgrid units after attachment of multiple subgrids together or after attachment of multiple support frames together. Instead of multiple Independent subgrids that are attached together to form a single unit, one subgrid structure may be fabricated that Is the desired size of the screen assembly. Individual screen éléments may then be attached to the one subgrid structure.

Figure 38 Is a flow chart showing steps to fabricate a screen assembly, according to an exemplary embodiment of the présent invention. A thermopiastic screen element may be Injection molded. Subgrids may be fabricated such that they are configured to receive the screen éléments. Screen éléments may be attached to subgrids and multiple subgrid assemblies may be attached, forming a screening surface. Altematively, the subgrids may be attached to each other prior to attachment of screen éléments.

In another exemplary embodiment, a method for screening a material is provided, Including attaching a screen assembly to a vibratory screening machine and forming a top screening surface of the screen assembly Into a concave shape, wherein the screen assembly Indudes a screen element having a sériés of screening openings forming a screen element screening surface and a subgrid including multiple elongated structural members forming a grid framework having grid openings. The screen éléments span grid openings and are secured to a top surface of the subgrid. Multiple subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces. The screen element is a single thermopiastic injection molded piece.

Figure 39 Is an Isométrie view of a vibratory screening machine having a single screen assembly 89 with a fiat screening surface installed thereon with a portion of the vibratory machine eut away showing the screen assembly. Screen assembly 89 is a single unit that Inciudes a subgrid structure and screen éléments as described herein. The subgrid structure may be one single unit or may be multiple subgrids attached together. While screen assembly 89 Is shown as a 42 generally fiat type assembiy, it may be convex or concave and may be configured to be deformed Into a concave shape from a compression assembiy or the like. It may also be configured to be tensloned from above or below or may be configured In another manner for attachment to different types of vibratory screening machines. While the embodiment of the screen assembiy shown covers the entire screening bed of the vibratory screening machine, screen assembiy 89 may also be configured in any shape or size desired and may cover only a portion of the screening bed.

Figure 40 ls an Isométrie view of a screen element 99 according to an exemplary embodiment of the présent invention. Screen element 99 is substantially triangular in shape. Screen element 99 ls a single thermoplastic Injection molded piece and has similar features (Including screening opening sizes) as screen element 16 as described herein. Altemativeiy, the screen element may be rectangular, drcular, triangular, square, etc. Any shape may be used for the screen element and any shape may be used for the subgrid as long as the subgrid has grid openings that correspond to the shapes of the screen éléments.

Figures 40A and 40B show screen element structure 101, which may be a subgrid type structure, with screen éléments 99 attached thereto forming a pyramid shape. In an alternative embodiment the complété pyramid structure of screen element structure 101 may be thermoplastic injection molded as a single screen element having a pyramid shape. In the configuration shown, the screen element structure has four triangular screen element screening surfaces. The bases of two of the triangular screening surfaces begin at the two side members of the screen element and the bases of the other two triangular screening surfaces begin at the two end members of the screen element. The screening surfaces ail slope upward to a center point above the screen element end members and side members. The angle of the sloped screening surfaces may be varied. Screen element structure 101 (or altemativeiy single screen eiement pyramide) may be attached to a subgrid structure as described herein.

Figures 40C and 40D show a screen element structures 105 with screen éléments 99 attached and having a pyramidal shape dropplng below side members and edge members of the screen element structure 105. Altemativeiy, the entire pyramid may be thermoplastic injection molded as a single pyramid shaped screen element. In the configuration shown, Individual screen éléments 99 form four triangular screening surfaces. The bases of two of the triangular screening surfaces begin at the two side members of the screen element and the bases of the other two triangular screening surfaces begin at the two end members of the screen element. The screening surfaces ail slope downward to a center point below the screen element end members and side members. The angle of the sloped screening surfaces may be varied. Screen element structure 105 (or altemativeiy single screen element pyramlds) may be attached to a subgrid structure as described herein.

Figures 40E and 40F show a screen element structure 107 having multiple pyramidal shapes dropplng below and rising above the side members and edge members of screen element structure 107. Each pyramid Includes four individual screen éléments 99 but may also be formed as single screen element pyramid. In the configuration shown, each screen element has slxteen triangular screening surfaces forming four separate pyramidal screening surfaces. The pyramidal screening surfaces may siope above or below the screen element end members and side members. Screen element structure 107 (or altematively single screen element pyramlds) may be attached to a subgrid structure as described herein. Figures 40 through 40F are exemplary only as to the variations that may be used for the screen éléments and screen element support structures.

Figures 41 to 43 show cross-sectional profile views of exemplary embodiments of thermoplastic Injection molded screen element surface structures that may be incorporated Into the various embodiments of the présent invention discussed herein. The screen element ls not limited to the shapes and configurations Identified herein. Because the screen element ls thermoplastic Injection molded, multiple variations may be easlly fabricated and incorporated into the various exemplary embodiments discussed herein.

Figure 44 shows a prescreen structure 200 for use with vibratory screening machines. Prescreen structure 200 Includes a support frame 300 that is partially covered with Individual prescreen assemblies 210. Prescreen assemblies 210 are shown having multiple prescreen éléments 216 mounted on prescreen subgrids 218. Although, prescreen assemblies 210 are shown Including six prescreen subgrids 218 secured together, various numbers and types of subgrids may be secured together to form various shapes and sizes of prescreen assemblies 210. The prescreen assemblies 210 are fastened to support frame 300 and form a continuous prescreening surface 213. Prescreen structure 200 may be mounted over a primary screening surface. Prescreen assemblies 210, prescreen éléments 216 and the prescreen subgrids 218 may Include any of the features of the various embodiments of screen assemblies, screen éléments and subgrid structures described herein and may configured to be mounted on prescreen support frame 300, which may hâve various forms and configurations suitable for prescreening applications. Prescreen structure 200, prescreen assemblies 210, prescreen éléments 216 and the prescreen subgrids 218 may be configured to be Incorporated into the pre-screening technologies (e.g., compatible with the mounting structures and screen configurations) described in U.S. Patent Application No. 12/051,658.

Figure 44A shows an enlarged view of prescreen assembly 210.

The embodiments of the présent Invention described herein, Including screening members and screening assemblies, may be configured for use with various different vibratory screening machines and parts thereof, Including machines designed for wet and dry applications, machines 44 having muiti-tiered decks and/or multiple screening baskets, and machines having various screen attachment arrangements such as tensioning mechanisms (under and overmount), compression mechanisms, damping mechanisms, magnetic mechanisms, etc. For exampie, the screen assemblies described in the present disclosure may be configured to be mounted on the vibratory screening machines described In U.S. Patent Nos. 7,578,394; 5,332,101; 6,669,027; 6,431,366; and 6,820,748. Indeed, the screen assemblies described herein may include: side portions or binder bars Including U-shaped members configured to receive overmount type tensioning members, e.g., as described in U.S. Patent No. 5,332,101; side portions or binder bars Including finger receiving apertures configured to receive undermount type tensioning, e.g., as described In U.S. Patent No. 6,669,027; side members or binder bars for compression loading, e.g., as described in U.S. Patent No. 7,578,394; or may be configured for attachment and loading on muititiered machines, e.g., such as the machines described in U.S. Patent No. 6,431,366. The screen assemblies and/or screening éléments may also be configured to include features described in U.S. Patent Application Nos. 12/460,200, Including the guide assembly technologies described thereln and preformed pane! technologies described thereln. Still further, the screen assemblies and screening éléments may be configured to be Incorporated Into the pre-screening technologies (e.g., compatible with the mountlng structures and screen configurations) described in U.S. Patent Application No. 12/051,658. U.S. Patent Nos. 7,578,394; 5,332,101; 4,882,054; 4,857,176; 6,669,027; 7,228,971; 6,431,366; and 6,820,748 and U.S. Patent Application Nos. 12/460,200 and 12/051,658, which, along with their related patent familles and applications, and the patents and patent applications referenced in these documents, are expressiy incorporated herein by reference hereto.

in the foregolng, exampie embodiments are described. It will, however, be évident that various modifications and changes may be made thereunto without departing from the broader spirit and scope hereof. The spécification and drawings are accordingly to be regarded in an Illustrative rather than In a restrictive sense.

Claims (153)

1. WHAT IS CLAIMED IS:

   1. A screen assembly, comprising:

   a screen element including a screen element screening surface having a sériés of screening openings; and a subgrid Including multiple elongated structural members forming a grid framework having grid openings, wherein the screen element spans at least one of the grid openings and is attached to a top surface of the subgrid, wherein multiple independent subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface having multiple screen element screening surfaces, wherein the screen element Includes substantially parallel end portions and substantially parallel slde edge portions substantially perpendlcularto the end portions, wherein the screen element further includes a first screen element support member and a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallel to the side edge portions, the second screen element support member extending between the slde edge portions and being approximately parallel to the end portions, wherein the screen element includes a first sériés reinforcement members substantially parallel to the side edge portions, a second sériés of reinforcement members substantially parallel to the end portions, wherein the screen element screening surface includes screen surface éléments forming the screening openings, wherein the end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabilize screen surface éléments and screening openings, wherein the screen element 1s a single thermoplastic injection molded piece.
2. 2. The screen assembly of claim 1, wherein the screen surface éléments run parallel to the end portions and are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 1000 microns between inner surfaces of each screen surface element.
3. 3. The screen assembly of claim 1, wherein the screen surface éléments run parailel to the end portions and are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 70 microns to approximately 180 microns between Inner surfaces of each screen surface element.
4. 4. The screen assembly of claim 1, wherein the screen surface eiements run parailel to the end portions and are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 106 microns between inner surfaces of each screen surface element.
5. 5. The screen assembly of claim 1, wherein the screen surface éléments run parailel to the end portions and are elongated members forming the screening openings, the screening openings being elongated slots having a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
6. 6. The screen assembly of claim 1, wherein the subgrid is a single thermoplastic Injection molded plece.
7. 7. The screen assembly of claim 1, wherein a first subgrid Includes a first base member having a first fastener that mates with a second fastener of a second base member of a second subgrid, the first and second fasteners securing the first and second subgrids together.
8. 8. The screen assembly of claim 7, wherein the first fastener Is a clip and the second fastener Is a clip aperture, wherein the clip snaps Into the dip aperture and securely attaches the first and second subgrids together.
9. 9. The screen assembly of claim 1, wherein the first and second screen element support members and the screen element end portions Include a screen element attachment arrangement configured to mate with a subgrid attachment arrangement.
10. 10. The screen assembly of claim 9, whereln the subgrid attachment arrangement Indudes elongated attachment members and the screen element attachment arrangement indudes attachment apertures that mate with the elongated attachment members securely attaching the screen element to the subgrid.
11. 11. The screen assemblyof daim 10, whereln a portion ofthe elongated attachment members extends through the screen element attachment apertures and slightly above the screen element screening surface, the attachment apertures Induding a tapered bore such that when the portion of the elongated attachment members above the screening element screening surface Is melted It filis the tapered bore and fastens the screen element to the subgrid.
12. 12. The screen assembly of daim 10, whereln a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above the screen element screening surface, such that when the portion of the elongated attachment members above the screening element screening surface Is melted it forms a bead on the screening element screening surface and fastens the screen element to the subgrid.
13. 13. The screen assembly of daim 1, whereln the elongated structural members Indude substantially paraliei subgrid end members and substantlally paraliei subgrid side members substantially perpendicular to the subgrid end members, wherein the elongated strudurai members further indude a first subgrid support member and a second subgrid support member orthogonal to the first subgrid support member, the first subgrid support member extending between the subgrid end members and being approximately paraliei to the subgrid side members, the second subgrid support member extending between the subgrid side members and being approximately paraliei to the subgrid end members, and substantially perpendicular to the subgrid edge members.
14. 14. The screen assembly of daim 1, wherein the grid framework indudes a first and second grid framework forming a first and a second grid opening, the screen éléments induding a first and a second screen element, wherein the subgrid indudes a ridge portion and a base portion, the first and second grid frameworks Include first and second angular surfaces that peak at the ridge portion and extend downwardly from the peak portion to the base portion, wherein the first and second screen éléments span the first and second angular surfaces, respectiveiy.
15. 15. The screen assembly of daim 1, wherein the screening openings are at least one of rectangular, square, drcular, and oval in shape.
16. 16. The screen assembly of daim 1, whereln the screen surface éléments run parallel to the end portions and form the screening openings.
17. 17. A screen assembly, comprising:

    a screen element Induding a screen element screening surface having a sériés of screening openings; and a subgrid induding multiple elongated structural members forming a grid framework having grid openings, wherein the screen element spans at least one grid opening and is secured to a top surface of the subgrid, wherein multiple subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces, wherein the screen element is a single thermoplastic Injection molded piece.
18. 18. The screen assembly of daim 17, whereln the screen element Indudes substantially parallel end portions and substantially parallel side edge portions substantially perpendicular to the end portions, whereln the screen element further indudes a first screen element support member and a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallel to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallel to the end portions, whereln the screen element indudes a first sériés reinforcement members substantially parallel to the side edge portions, a second sériés of reinforcement members substantially parallel to the end portions, whereln the screen element includes elongated screen surface éléments running parallel to the end portions and forming the screening openings, wherein the end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabilize the screen surface éléments and the screening openings.
19. 19. The screen assembly of daim 18, wherein the first and second screen element support members and the end portions indude a screen element attachment arrangement configured to mate with a subgrid attachment arrangement.
20. 20. The screen assembly of daim 19, wherein the subgrid attachment arrangement Includes elongated attachment members and the screen element attachment arrangement includes attachment apertures that mate with the elongated attachment members that securely attach the screen element to the subgrid.
21. 21. The screen assembly of daim 20, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above the screen element screening surface, the attachment apertures induding a tapered bore such that when the portion of the elongated attachment members above the screening element screening surface Is meited It fills the tapered bore and fastens the screen element to the subgrid.
22. 22. The screen assembly of daim 20, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above the screen element screening surface, such that when the portion of the elongated attachment members above the screening element screening surface Is meited it forms a bead on the screening element screening ’ surface and fastens the screen element to the subgrid.
23. 23. The screen assembly of daim 18, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 43 microns to approximately 1000 microns between Inner surfaces of each screen surface element.
24. 24. The screen assembly of daim 18, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 70 microns to approximately 180 microns between Inner surfaces of each screen surface element.
25. 25. The screen assembly of daim 18, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximateiy 43 microns to approximateiy 106 microns between inner surfaces of each screen surface element.
26. 26. The screen assembly of daim 18, wherein the screening openings are elongated slots with a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
27. 27. The screen assembly of daim 18, wherein the first and second sériés of reinforcement members hâve a thickness less than a thlckness of the end portions, side edge portions and the first and second screen element support members.
28. 28. The screen assembly of daim 27, wherein the end portions and the side edge portions and the first and second screen element support members form four rectangular areas and the first sériés of reinforcement members and the second sériés of reînforcement members form multiple rectangular support grids within each of the four rectangular areas and the screening openings hâve an open space of approximateiy 43 microns to approximateiy 1000 microns between Inner surfaces of each of the screen surface éléments.
29. 29. The screen assembly of daim 27, wherein the end portions and the side edge portions and the first and second screen element support members form four rectangular areas and the first sériés of reinforcement members and the second sériés of reinforcement members form multiple rectangular support grids within each of the four rectangular areas and the screening openings hâve an open space of approximateiy 70 microns to approximateiy 180 microns between Inner surfaces of each of the screen surface éléments.
30. 30. The screen assembly of daim 27, wherein the end portions and the side edge portions and the first and second screen element support members form four rectangular areas and the first sériés of reinforcement members and the second sériés of reinforcement members form multiple rectangular support grids within each of the four rectangular areas and the screening openings hâve an open space of approximateiy 43 microns to approximateiy 106 microns between Inner surfaces of each of the screen surface éléments.
31. 31. The screen assembly of daim 27, wherein the end portions and the side edge portions and the first and second screen element support members form four rectangular areas and the first sériés of reinforcement members and the second sériés of reinforcement members form multiple rectangular support grids within each of the four rectangular areas and the screening openings hâve an open space of about 0.044 mm to about 4 mm of width and about 0.088 mm to about 60 mm ln length.
32. 32. The screen assembly of daim 27, wherein the screen éléments are flexible.
33. 33. The screen assembly of daim 17, wherein the elongated structural members indude substantiaily parallel subgrid end members and substantiaily parallel subgrid side members substantialiy perpendicular to the subgrid end members, wherein the elongated structural members further indude a first subgrid support member and a second subgrid support member orthogonal to the first subgrid support member, the first subgrid support member extending between the subgrid end members and being approximately parallel to the subgrid side members, the second subgrid support member extending between the subgrid side members and being approximately parallel to the subgrid end members.
34. 34. The screen assembly of daim 33, wherein the first and second subgrid support members indude a subgrid attachment arrangement configured to securely mate with a screen element attachment arrangement.
35. 35. The screen assembly of daim 33, wherein the subgrid attachment arrangement includes elongated attachment members and the screen element indudes a screen element attachment arrangement having attachment apertures that mate with the elongated attachment members and securely attach the screen element to the subgrid.
36. 36. The screen assembly of daim 33, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slïghtly above the screening element screening surface, the attachment apertures induding a tapered bore such that when the portion of the elongated attachment members above the screening element screening surface is melted it filis the tapered bore and fastens the screen element to the subgrid.
37. 37. The screen assembly of daim 33, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above the screening element screening surface, such that when the portion of the elongated attachment members above the screening element screening surface Is melted it forms a bead on the screening element screening surface and fastens the screen element to the subgrid.
38. 38. The screen assembly of daim 33, wherein the screen element indudes substantialiy parallel end portions and substantialiy parallel side edge portions substantialiy perpendicuiar to the end portions, wherein the screen element further Indudes a first screen element support member and a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approxlmately parallel to the side edge portions, the second screen element support member extending between the side edge portions and being approxlmately parallel to the end portions, the end portions, the side edge portions and the screen element Induding a screen element attachment arrangement configured to mate with a subgrid attachment arrangement, wherein the screen element indudes a first sériés reinforcement members substantialiy parallel to the to the side edge portions, a second sériés of reinforcement members substantialiy parallel to the end portions, wherein the screen element Indudes elongated screen surface éléments running parallel to the end portions and forming the screening openings, wherein the end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabilize screen surface éléments and screening openings.
39. 39. The screen assembly of daim 38, wherein the screening openings hâve width of approxlmately 43 microns to approxlmately 1000 microns between inner surfaces of each of the screen surface éléments.
40. 40. The screen assembly of daim 38, wherein the screening openings hâve a width of approxlmately 70 microns to approxlmately 180 microns between inner surfaces of each of the screen surface éléments.
41. 41. The screen assembly of daim 38, wherein the screening openings hâve a width of approxlmately 43 microns to approxlmately 106 microns between Inner surfaces of each of the screen surface éléments.
42. 42. The screen assembly of daim 38, wherein the screening openings are elongated slots having a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
43. 43. The screen assembly of daim 38, wherein the subgrid end members, the subgrid side members and the first and second subgrid support members form eight rectanguiar grid openings and a first screen element spans four of the grid openings and a second screen element spans the other four openings, the first and second support members of the screen element In line with the first and second subgrid support members.
44. 44. The screen assembly of daim 43, wherein a central portion of the screening element screening surface slightly flexes when subject to a load.
45. 45. The screen assembly of daim 33, wherein the subgrid Is substantially rigld.
46. 46. The screen assembly of daim 33, wherein the subgrid Is a single thermoplastic Injection molded piece.
47. 47. The screen assembly of daim 33, wherein at least one of the subgrid end members and the subgrid side members Includes fasteners configured to mate with fasteners of other subgrids.
48. 48. The screen assembly of daim 47, wherein the fasteners are clips and dip apertures that snap into place and securely attach the subgrids together.
49. 49. The screen assembly of daim 17, wherein the subgrid Indudes substantially parallel triangularend pièces, triangular mlddle pièces substantially parallel to the triangular end pièces, a first and second mid support substantially perpendicular to the triangular end pièces and extending between the triangular end pièces, a first and second base support substantially perpendicularto the triangularend pièces and extending between the triangular end pièces and a central ridge substantially perpendicular to the triangular end pièces and extending between the triangular end pièces, wherein a first edge of the triangular end pièces, the triangular middle pièces, the first mid support, the first base support and the central rldge form a first top surface of the subgrid having a first sériés of grid openings and a second edge of the triangular end pièces, the triangular middle pièces, the second mid support, the second base support and the central ridge form a second top surface of the subgrid having a second sériés of grid openings, the first top surface sloping from the central ridge to the first base support, the second top surface sloping from the central ridge to the second base support, wherein a first and a second screen element span the first sériés and second sériés of grid openings, respectively.
50. 50. The screen assembly of daim 49, wherein the first edges of the triangular end pièces, the triangular middle pièces, the first mid support, the first base support and the central ridge indude a first subgrid attachment arrangement configured to securely mate with a first screen element attachment arrangement of the first screen element, wherein the second edges of the triangular end pièces, the triangular middle pièces, the second mid support, the second base support and the central ridge Indude a second subgrid attachment arrangement configured to securely mate with a second screen element attachment arrangement of the second screen element.
51. 51. The screen assembly of daim 50, wherein the first and second subgrid attachment arrangements Indude elongated attachment members and the first and second screen element attachment arrangements indude attachment apertures that mate with the elongated attachment members thereby securely attaching the first and second screen éléments to the first and second subgrids, respectively.
52. 52. The screen assembly of claim 51, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above a first and second screen element screening surface, the attachment apertures Induding a tapered bore such that when the portion of the elongated attachment members above the first and second screening element screening surfaces is melted it fills the tapered bore and fastens the first and second screen éléments to the first and second subgrids, respectively.
53. 53. The screen assembly of daim 51, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above a first and second screen element screening surface, such that when the portion of the elongated attachment members above the first and second screen element screening surfaces Is melted it forms a bead on the screen element screening surface and fastens the screen element to the subgrid.
54. 54. The screen assembly of daim 49, wherein the first and second screen éléments each Indude substantially parallei end portions and substantially parallei side edge portions substantially perpendicuiar to the end portions, wherein the first and second screen éléments each indude a first screen element support member and a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallei to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallei to the end portions, wherein the first and second screen éléments each Include a first sériés reinforcement members substantially parallei to the to the side edge portions, a second sériés of reinforcement members substantially parallei to the end portions, wherein the first and second screen éléments each Indude elongated screen surface éléments running parallei to the end portions and forming the screening openings, wherein the end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabilize screen surface éléments and screening openings.
55. 55. The screen assembly of daim 54, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 43 microns to approximately 1000 microns between Inner surfaces of each screen surface element..
56. 56. The screen assembly of daim 54, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 70 microns to approximately 180 microns between inner surfaces of each screen surface element.
57. 57. The screen assembly of daim 54, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 43 microns to approximately 106 microns between Inner surfaces of each screen surface element
58. 58. The screen assembly of daim 54, wherein the screening openings are elongated slots with a width and a length the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
59. 59. The screen assembly of daim 54, wherein at least one of the first and second base supports Indudes fasteners that secure the multiple subgrids together.
60. 60. The screen assembly of daim 59, wherein the fasteners are dlps and dip apertures that snap Into place and securely attach subgrids together.
61. 61. The screen assembly of daim 54, further comprising a first, second, third and fourth screen element, wherein the first sériés of grid openings Is eight openings formed by the first edge of the triangular end pièces, the triangular middle pièces, the first mld support, the first base support and the central ridge and the second sériés of grid openings Is elght openings formed by the second edge of the triangular end pièces, the triangular middle pièces, the second mld support, the second base support and the central ridge, wherein the first screen element spans four of the grid openings of the first sériés of grid openings and the second screen element spans the other four openings of the first sériés of grid openings, the first and second support members of the first screen element In line with the edge of the first mid support and the first edges of the triangular end pièces and the triangular middle pièces, the first and second support members ofthe second screen element In line with the edges of the second mid support and the second edges of the triangular end pièces and the triangular middle pièces, wherein the third screen element spans four of the grid openings of the second sériés of grid openings and the fourth screen element spans the other four openings of the second sériés of grid openings, the first and second support members of the third screen element in line with the edge ofthefirst mid supportand the first edges ofthe triangularend piècesand the triangular middle pièces, the first and second support members of the fourth screen element In line with the edges of the second mid support and the second edges of the triangular end pièces and the triangular middle pièces.
62. 62. The screen assembly of daim 61, wherein a central portion of the first, second, third and fourth screening element screening surfaces slightly flex when subject to a load.
63. 63. The screen assembly of daim 49, wherein the subgrid Is substantially rigid.
64. 64. The screen assembly of daim 49, wherein the subgrid Is a single thermoplastic Injection molded plece.
65. 65. A screen assembly, comprising:

    a screen element Induding a screen element screening surface having screening openings; and a subgrid Induding a grid Framework having grid openings, wherein the screen element spans the grid openings and is attached to a surface of the subgrid, wherein multiple subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces, wherein the screen element is an Injedion molded plece.
66. 66. The screen assembly of daim 65, wherein the screen element is rectangularand has an approximately two inch width and an approximately three inch length and the screening openings are formed by screen surface éléments having a thickness of approximately 43 microns to approximately 100 microns.
67. 67. The screen assembly of daim 65, wherein the screen element is a thermoplastic Injection molded piece.
68. 68. The screen assembly of daim 65, further comprising a first screen element and a second screen element, wherein the grid framework Indudes a first and second grid framework forming a first grid opening and a second grid opening, wherein the subgrid Includes a ridge portion and a base portion, the first and second grid frameworks Include first and second angular surfaces that peak at the ridge portion and extend downwardly from the peak portion to the base portion, wherein the first and second screen éléments span the first and second angular surfaces, respectively.
69. 69. The screen assembly of daim 68, wherein the first and second angular surfaces Indude a subgrid attachment arrangement configured to securely mate with a screen element attachment arrangement
70. 70. The screen assembly of daim 69, wherein the subgrid attachment arrangement includes elongated attachment members and the screen element attachment arrangement indudes apertures that mate with the elongated attachment members thereby secureiy attaching the screen éléments to the subgrid.
71. 71. The screen assembiy of daim 69, wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above the screen element screening surface, the attachment apertures indudlng a tapered bore such that when the portion of the elongated attachment members above the screening element screening surface is melted It fills the tapered bore and fastens the screen element to the subgrid.
72. 72. The screen assembly of daim 69,wherein a portion of the elongated attachment members extends through the screen element attachment apertures and slightly above the screen element screening surface such that when the portion of the elongated attachment members above the screening element screening surface Is melted it forms a bead on the screening element screening surface and fastens the screen element to the subgrid.
73. 73. The screen assembly of daim 65, wherein each screen element indudes substantially parallel end portions and substantially parallel side edge portions substantially perpendicular to the end portions, wherein each screen element Indudes a first screen element support member and a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallel to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallel to the end portions, wherein each screen eiement Indudes a first sériés reinforcement members substantially parallel to the side edge portions, a second sériés of reinforcement members substantially parallel to the end portions, wherein each screen element screening surface Includes screen surface éléments runnlng parallel to the end portions and forming the screening openings, wherein the end portions, slde edge portions, first and second support members, first and second sériés of reinforcement members structurally stabilize screen surface éléments and screening openings.
74. 74. The screen assembly of claim 65, wherein the subgrid Includes substantially parallel subgrid end members and substantially parallel subgrid slde members substantially perpendicularto the subgrid end members, wherein the grid framework Includes elongated structural members Including a first subgrid support member and a second subgrid support member orthogonal to the first subgrid support member, the first subgrid support member extending between the subgrid end members and being approximately parallel to the subgrid side members, the second subgrid support member extending between the subgrid slde members and being approximately parallel to the subgrid end members.
75. 75. The screen assembly of daim 65, wherein the screen element Indudes a screen element attachment arrangement that mates with a subgrid attachment arrangement and secures the screen element to the subgrid.
76. 76. The screen assembly of daim 65, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 43 microns to approximately 1000 microns between Inner surfaces of each of the screen surface éléments.
77. 77. The screen assembly of daim 65, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 70 microns to approximately 180 microns between Inner surfaces of each of the screen surface éléments.
78. 78. The screen assembly of daim 65, wherein the screening openings are elongated slots with a width and a length, the width of the screening openings being approximately 43 microns to approximately 106 microns between Inner surfaces of each of the screen surface éléments.
79. 79. The screen assembly of claim 65, wherein the screening openings are elongated slots with a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
80. 80. The screen assembly of daim 68, wherein the subgrid Is substantially rigid.
81. 81. The screen assembly of daim 68, wherein the subgrid Is a single thermoplastic injection molded piece.
82. 82. The screen assembly of daim 68, wherein a section of the base portion Indudes a first and a second fastener that secures the subgrid to a third and a fourth fastener of another subgrid.
83. 83. The screen assembly of daim 68, whereln the first and third fasteners are clips and the second and fourth fasteners are clip apertures, whereln the clips snap into dip apertures and securely attach the subgrid and the another subgrid together.
84. 84. The screen assembly of daim 65, whereln subgrids form a concave structure and the continuous screen assembly screening surface Is concave.
85. 85. The screen assembly of daim 65, whereln the subgrids form a fiat structure and the continuous screen assembly screening surface Is fiat
86. 86. The screen assembly of daim 65, wherein the subgrids form a convex structure and the continuous screen assembly screening surface is convex.
87. 87. The screen assembly of daim 65, whereln the screen assembly is configured to form a predetermlned concave shape when subjected to a compression force by a compression assembly of a vlbratory screening machine against at least one side member of the vlbratory screen assembly when placed In the vibratory screening machine.
88. 88. The screen assembly of daim 87, wherein the predetermined concave shape is determined in accordance with a shape of a surface of the vibratory screening machine.
89. 89. The screen assembly of daim 87, further comprising a mating surface mating the screen assembly to a surface of the vibratory screening machine.
90. 90. The screen assembly of daim 89, wherein the mating surface Is at least one of a rubber, a métal and a composite material.
91. 91. The screen assembly of daim 65, wherein the screen assembly indudes a mating surface and that Is configured to Interface with a mating surface of a vibratory screening machine such that the screen assembly Is gulded Into a fixed position on the vibratory screening machine.
92. 92. The screen assembly of daim 91, wherein the mating surface Is formed In a portion of at least one subgrid.
93. 93. The screen assembly of daim 91, wherein the screen assembly mating surface Is a notch formed in a corner of the screen assembly.
94. 94. The screen assembly of daim 91, wherein the screen assembly mating surface Is a notch formed approximately In the middle of a side edge of the screen assembly.
95. 95. The screen assembly of daim 65, wherein the screen assembly has an arched surface configured to mate with a concave surface of the vibratory screening machine, the screen assembly having a substantially rigid structure that does not substantially deflect when secured to the vibratory screening machine.
96. 96. The screen assembly of daim 65, wherein the screen assembly Inciudes a screen assembly mating surface, the screen assembly configured such that it forms a predetermlned concave shape when subjected to a compression force by a member of a vibratory screening machine, wherein the screen assembly mating surface is shaped such that it interfaces with a mating surface of the vibratory screening machine such that the screen assembly is gulded into a predetermined location on the vibratory screening machine.
97. 97. The screen assembly of daim 65, further comprising a load bar attached to an edge surface of the subgrid of the screen assembly, the load bars configured to distribute a load across a surface of the screen assembly.
98. 98. The screen assembly of daim 97, wherein the screen assembly Is configured to form a predetermined concave shape when subjected to a compression force by a compression member of a vibratory screening machine against the load bar of the vibratory screen assembly.
99. 99. The screen assembly of daim 65, wherein the screen assembly has a concave shape and Is configured to deflect and form a predetermined concave shape when subjected to a compression force by a member of a vibratory screening machine.
100. 100. The screen assembly of claim 65, wherein a first set of the subgrids is formed Into center support frame assemblies having a first fastener arrangement, a second set of the subgrids Is formed into a first end support frame assembly having a second fastener arrangement, and a third set of the subgrids Is formed into a second end support frame assembly having a third fastener arrangement, wherein the first, second, and third fastener arrangements secure the first and second end support frames to the center support assemblies, a side edge surface of the first end support frame assembly forming a first end of the screen assembly, a side edge surface of the second end support frame arrangement forming a second end of the screen assembly and an end surface of each of the first and second end support frame assemblies and center support frame assemblies cumulatively forming a first and a second side surface of the complété screen assembly, wherein the first and second side surfaces of the screen assembly are substantiaily parallel and the first and second end surfaces of the screen assembly are substantiaily parallel and substantiaily perpendicular to the side surfaces of the screen assembly.
101. 101. The screen assembly of claim 100, wherein the side surfaces of the screen assembly Include fasteners configured to engage at least one of a binder bar and a load distribution bar.
102. 102. The screen assembly of claim 100, wherein the subgrids Include side surfaces shaped such that when Individual subgrids are secured together to form the first and second end support frame assemblies and the center support frame assembly that the first and second end support frame assemblies and the center support frame assembly each form a concave shape.
103. 103. The screen assembly of claim 100, wherein the subgrids Include side surfaces shaped such that when Individuel subgrids are secured together to form the first and second end support frame assemblies and the center support frame assembly that the first and second end support frame assemblies and the center support frame assembly each form a convex shape.
104. 104. The screen assembly of claim 100, whereln the subgrid Inciudes substantially paraliei subgrid end members and substantially paraliei subgrid side members substantially perpendicular to the subgrid end members, whereln the subgrid Inciudes a first subgrid support member and a second subgrid support member orthogonal to the first subgrid support member, the first subgrid support member extending between the subgrid end members and being approximately paraliei to the subgrid side members, the second subgrid support member extending between the subgrid side members and being approximately paraliei to the subgrid end members.
105. 105. The screen assembly of claim 100, wherein the grid framework Inciudes a first and second grid framework forming a first and a second grid opening, the screen element Indudes a first and a second screen element, whereln the subgrid Indudes a ridge portion and a base portion, the first and second grid frameworks Indude first and second angular surfaces that peak at the ridge portion and extend downwardly from the peak portion to the base portion, whereln the first and second screen éléments span the first and second angular surfaces.
106. 106. The screen assembly of claim 100, wherein the subgrid Indudes substantially paraliei subgrid end members and substantlally paraliei subgrid side members substantially perpendicular to the subgrid end members, whereln the subgrid further Inciudes subgrid support members molded integrally with subgrid end members and subgrid side members.
107. 107. The screen assembly of daim 65, whereln the grid framework Indudes a first and second grid framework forming a first and a second grid opening, the screen element Indudes a first and a second screen element, wherein the subgrid Includes a ridge portion and a base portion, the first and second grid frameworks Include first and second angular surfaces that peak at the ridge portion and extend downwardly from the peak portion to the base portion, the first and second angular surfaces, wherein the first and second screen éléments span the first and second angular surfaces.
108. 108. The screen assembly of claim 65, wherein the screen éléments are affïxed to the subgrids by at least one of a mechanical arrangement, an adhesive, heat staking and uitrasonic welding.
109. 109. The screen assembly of claim 65, wherein the screen assembly Includes side surfaces having fasteners configured to engage at least one of a binder bar and a load distribution bar.
110. 110. A screen element, comprising:

     a screen element screening surface having screen surface éléments forming a sériés of screening openings;

     a pair of substantiaily parallel end portions;

     a pair of substantiaily parallel side edge portions substantiaily perpendicular to the end portions;

     a first screen element support member;

     a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallel to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallel to the end portions, and substantiaily perpendicular to the side edge portions;

     a first sériés reinforcement members substantiaily parallel to the to the side edge portions;

     a second sériés of relnforcement members substantialiy parallel to the end portions, wherein the end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabillze screen surface éléments and screening openings and the screen element Is a single Injection molded piece, wherein the screen surface éléments are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 1000 microns between inner surfaces of each screen surface element.
111. 111. The screen element of daim 110, wherein the screen element is a single thermoplastic injection molded piece.
112. 112. The screen element of daim 110, wherein the screen element Is redangular and has an approximately two Inch width and an approximately three Inch length.
113. 113. The screen element of daim 110, wherein the screen surface éléments run parallel to the end portions.
114. 114. The screen element of claim 110, wherein the screen surface éléments run perpendicular to the end portions.
115. 115. The screen element of daim 110, wherein the screen element screening surface has a corrugated shape.
116. 116. The screen element of daim 110, wherein the screen surface éléments are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 70 microns to approximately 180 microns between inner surfaces of each screen surface element.
117. 117. The screen element of daim 110, wherein the screen surface éléments are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 106 microns between inner surfaces of each screen surface element.
118. 118. The screen element of daim 110, wherein the screening openings are elongated slots having a width and a length. the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
119. 119. A screen element, comprising: an edge portion and a screen element screening surface having screen surface éléments forming a sériés of screening openings, wherein the screen element is a thermoplastic injection molded piece.
120. 120. The screen element of daim 119, wherein the screen surface éléments are elongated members forming the screening openings, the screening opening being elongated slots having a distance of approximately 43 microns to approximately 1000 microns between Inner surfaces of each screen surface element.
121. 121. The screen element of daim 119, wherein the screen surface éléments are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 70 microns to approximately 180 microns between Inner surfaces of each screen surface element.
122. 122. The screen element of daim 119, wherein the screen surface éléments are elongated members forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 106 microns between Inner surfaces of each screen surface element.
123. 123. The screen element of daim 119, wherein the screening openings are elongated slots having a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
124. 124. The screen element of daim 119, further comprising a pair of substantially parallel end portions, a pair of substantially parallel side edge portions substantially perpendicular to the end portions, a first screen element support member; a second screen element support member orthogonal to the first screen element support member, the first screen element support member extending between the end portions and being approximately parallel to the side edge portions, the second screen element support member extending between the side edge portions and being approximately parallel to the end portions, the end portions, the side edge portions; a first sériés reinforcement members substantially parallel to the to the side edge portions; a second sériés of reinforcement members substantially parallel to the end portions, wherein the screen surface éléments run parallel to the end portions, wherein the end portions, side edge portions, first and second support members, first and second sériés of reinforcement members structurally stabilize screen surface éléments and screening openings.
125. 125. The screen element of claim 119, further comprising a screen element attachment arrangement molded integraily with the screen element and configured to mate with a subgrid attachment arrangement, wherein multiple subgrids form a screen assembly and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces.
126. 126. A method for fabricating a screen assembly for screening materials, comprising:

     determining screen assembly performance spécifications for the screen assembly; determining a screening opening requirement for a screen element based on the screen assembly performance spécifications, the screen element Including a screen element screening surface having screening openings;

     determining a screen configuration based on the screen assembly performance spécifications, the screen configuration Including the screen éléments arranged in at least one of fiat configuration and a nonflat configuration;

     Injection moldïng the screen éléments;

     fabricating a subgrid configured to support the screen éléments, the subgrid having a grid framework with grid openings wherein at least one screen element spans at least one grid opening and Is secured to a top surface ofthe subgrid, the top surface of each subgrid Including at least one of a fiat surface and a nonflat surface that receives the screen éléments;

     attaching the screen éléments to the subgrids;

     attaching multiple subgrids together to form end support frames and center support frames;

     attaching the end support frames to the center support frames to form a support frame structure;

     attaching a first binder bar to a first end of the support frame structure and attaching a second binder bar to a second end of the support frame structure to form the screen assembly, the screen assembly having a continuous screen assembly screening surface comprised of multiple screen element screening surfaces.
127. 127. The method of daim 126, wherein the screen assembly performance spécifications Indude at least one of dimensions, material requirements, open screening area, eut point, and capadty requirements for a screening application.
128. 128. The method of daim 126, further comprising attaching a handle to the binder bar.
129. 129. The method of daim 126, further comprising attaching a tag to the binder bar wherein the tag indudes a performance description of the screen assembly.
130. 130. The method of daim 126, wherein the screen element Indudes screen surface éléments forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 1000 microns between Inner surfaces of each screen surface element.
131. 131. The method of daim 126, wherein the screen element indudes screen surface éléments forming the screening openings, the screening openings being elongated slots having a distance of approximately 70 microns to approximately 180 microns between inner surfaces of each screen surface element.
132. 132. The method of daim 126, wherein the screen element Indudes screen surface éléments forming the screening openings, the screening openings being elongated slots having a distance of approximately 43 microns to approximately 106 microns between inner surfaces of each screen surface element.
133. 133. The method of daim 126, wherein the screen eiement indudes screen surface éléments forming the screening openings, the screening openings being elongated slots having a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
134. 134. The method of daim 126, wherein at least one of the screen element and the subgrid ls a single thermoplastic injection molded piece.
135. 135. The method of daim 126, wherein the subgrid Indudes at least one base member having fasteners that mate with fasteners of other base members of other subgrids and secure the subgrids together.
136. 136. The method of daim 135, wherein the fasteners are dips and dip apertures that snap into place and securely attach the subgrids together.
137. 137. The method of daim 126, wherein the screen element Includes a screen eiement attachment arrangement configured to mate with a subgrid attachment arrangement.
138. 138. A method forfabricating a screen assembly for screening materials, comprising:

     Injection molding a screen element, the screen element Including a screen element screening surface having screening openings;

     fabricating a subgrid that supports the screen element, the subgrid having a grid framework with grid openings, the screen element spanning at least one grid opening; and securing the screen element to a top surface of the subgrid, the screen assembly having a continuous screen assembly screening surface comprised of multiple screen element screening surfaces.
139. 139. The method of claim 138, further comprising attaching a first binder barto a first end of the screen assembly and attaching a second binder bar to a second end of the screen assembly, wherein the first and second binder bars bind the subgrids together.
140. 140. The method of daim 139, wherein the binder bar is configured to distribute a load across the first and second ends of the screen assembly.
141. 141. The method of daim 138, wherein the screen element indudes screen surface éléments formlng the screening openings, the screening openings being eiongated slots having a distance of approximately 43 microns to approximately 1000 microns between inner surfaces of each screen surface element.
142. 142. The method of daim 138, wherein the screen element Indudes screen surface éléments formlng the screening openings, the screening openings being eiongated slots having a distance of approximately 70 microns to approximately 180 microns between Inner surfaces of each screen surface element
143. 143. The method of daim 138, wherein the screen eiement Indudes screen surface éléments formlng the screening openings, the screening opening being eiongated slots having a distance of approxlmately 43 microns to approxlmately 106 microns between inner surfaces of each screen surface element.
144. 144. The method of daim 138, wherein the screen element indudes screen surface éléments forming the screening openings, the screening openings being elongated slots having a width and a length, the width being about 0.044 mm to about 4 mm and the length being about 0.088 mm to about 60 mm.
145. 145. The method of daim 138, wherein at least one of the screen element and the subgrid ts a single thermoplastic Injection molded piece.
146. 146. The method of daim 138, wherein the subgrid indudes at least one base member having fasteners that mate with fasteners of other base members of other subgrids and secure the subgrids together.
147. 147. The method of daim 146, wherein the fasteners are dips and dip apertures that snap into place and securely attach the subgrids together.
148. 148. The method of daim 138, wherein the screen element indudes a screen element attachment arrangement configured to mate with a subgrid attachment arrangement.
149. 149. A method for screening a material, comprising attaching a screen assembly to a vibratory screening machine, the screen assembly inciuding a screen element having a sériés of screening openings forming a screen element screening surface; and a subgrid induding multiple elongated structurai members forming a grid framework having grid openings, wherein screen éléments span grid openings and are secured to a top surface of the subgrid, wherein multiple subgrids are secured together to form the screen assembly and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces, wherein the screen element is a single thermopiastic injection molded piece; screening the material using the screen assembly.
150. 150. A method for screening a material, comprising:

     attaching a screen assembly to a vibratory screening machine;

     forming a top screening surface of the screen assembly into a concave shape, wherein the screen assembly includes a screen element having a sériés of screening openings forming a screen element screening surface; and a subgrid including multiple elongated structural members forming a grid framework having grid openings, wherein screen éléments span grid openings and

     5 are secured to a top surface of the subgrid, wherein multiple subgrids are secured together to form the screen assembiy and the screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces, wherein the screen element is a single thermopiastic Injection molded piece; and screening the material using the screen assembly.
151. 151. The screen element of claim 119, wherein the screening openings are elongated slots having a width and a length, the width to length ratio being approximately 1:50.
152. 152. The screen element of claim 119, wherein the screening openings are elongated slots having 15 a width and a length, the width to length ratio being approximately 1:100.
153. 153. The method of claim 138, further comprising attaching multiple subgrids together to form the screen assembly.