EP1755793A2 - Tubular screen separator - Google Patents

Abstract

A screen assembly is disclosed. The screen assembly may have a feed hopper manifold, in series or parallel. The screen elements are in the form of a single flow directing channel, and the elements are individually replaceable. Such elements may be in the tubular or channel form.

Description

TUBULARSCREENSEPARATOR

CROSS REFERENCE TORELATEDAPPLICATION

This application claims priority of Provisional Application Serial No. 60/566,656 filed April 30, 2004 by Lilie et al and entitled "Tubular Screen Shaker" and is a continuation in part of U.S. Patent Application Serial No. 10/922,342 filed August 20, 2004.

BACKGROUND OF THE INVENTION

Field of the Invention

The field of the present invention is vibratory screen shakers and associated screen assemblies.

Prior Art

Vibratory screen separators have long been known which include a base, a resiliently mounted housing, a vibratory drive connected to the housing and screen assemblies positioned on the housing. The screen assemblies installed in vibratory screen separators are typically planar or very slightly crowned and are constructed in circular or rectangular frames with a single or a plurality of layers of screening media bonded on them to provide a screening surface. In some cases the screening media is pleated prior to bonding it on the support frame to provide increased screening area. See U.S. Patent No. 6,484,885, issued November 26, 2002 by Glenn Lilie, entitled Solids Raised Screens See U.S. Patent No. 4,820,407 issued April, 1989 by Glenn Lilie, entitled Solid Screens. Some screen media is "corrugated" to form those pleats. See U.S. Patents 5,636,749, issued June 10, 1997, by Wojciechowski, entitled "Undulating Screen for Vibratory Screening Machine", U.S. Patent 5,417,858, issued May 23, 1995, by Derrick et al. entitled "Screen Assembly for Vibrating Screening Machine", and U.S. Patent 5,417,859,issued May 23, 1995, by Bakula, entitled "Undulating Screen for Vibratory Screening Machine and Method of Fabrication Thereof. Some vibratory screen separators have also been designed with multiple decks capable of directing fluid in either parallel or series flow over multiple decks. See U.S. Patent No. 6,530,482 issued March 11, 2003 by Mike Wiseman, entitled Tandem Shale Shaker. In most screening processes, particularly in the case where gravity flow is used to distribute unscreened material to one or more vibratory screen separators, the available space limits the possibility of increasing the screening surface area by increasing the size of the separator or by adding to the number of vibratory screen separators. It is the object of the present invention to enable increasing the screening area without increasing the footprint or installed space of the vibratory screen separators.

It is a further object of the present invention to permit parallel flow or series flow over multiple decks with the lowest deck indicating upper deck screen element failure or other conditions that might cause oversize particles to be discharged with the screened material.

It is a further object of the present invention to improve operator safety.

It is a further object of the present invention to provide fume containment, fume evacuation, or removal of entrained gas from the fluid being screened.

It is a further object of the present invention to improve recovery of the liquid portion and discharge drier oversize solids.

It is a further object of the invention to include screen elements that are easily recycled in cases where the elements can be constructed primarily of stainless steel and non-metallic adhesives.

SUMMARY OF THE INVENTION

The present invention is directed to a screen assembly for vibratory separators including one or more screening surfaces constructed of individually replaceable tube shaped screen elements or individually replaceable screen elements shaped into a single flow directing channel. Screening surface area is created by placing these individually replaceable screen elements side by side with the long axis of the screen elements arranged to lie on a common- plane or on a common radius. When more than one arrangement of side by side screen elements is required to provide the necessary screening area, the preferred embodiment of additional arrangements of side by side screen elements is a vertical stacking in the fashion of a multi-deck vibratory separator. A second embodiment of the additional arrangements of side by side screen elements is to locate the additional arrangements of side by side screen elements essentially on the same plane as the first arrangement of side by side screen elements in the fashion of a single deck multiple screen panel vibratory separator. A third embodiment of the additional arrangements of multiple screen elements is to locate the additional arrangements in co-axial circles as to be explained further.

The screen elements include one or more layers of screen media formed into the shape of a tube or the shape of a single flow directing channel. If multiple layers of screen media are used, the layers may be seam welded, laminated, or otherwise joined together. Preferably the finest screen media (media with the smallest size opening) is placed on the inside diameter and other layers are progressively coarser towards the outside. The combined surface area of these screen elements translates into a larger screening surface area when compared on the basis of screen surface area per unit area of installed space for other known screening equipment.

In a first aspect of the present invention, the size of the screen openings for the innermost layer of screen media is determined by the desired screening process. The subsequent (radially outward) layers of screen media are typically coarser with larger openings and provide support, resiliency, and rigidity to the tubular or channel shaped screen element.

In a second aspect of the present invention, the screen elements of the vibratory separator are located in two or more vertically stacked decks and are fluidly connected to a feed manifold. The feed manifold distributes the unscreened material in parallel flow to one or more decks containing the side by side arrangements of tube shaped or channel shaped screen elements. Each deck is separated from the lower decks by a flow-back pan that directs the screened material into the bottom pan or sump without passing through more than one screen element unless deliberately redirected to the lowest most deck for quality assurance purposes. The material retained inside the screen elements will be conveyed along the inside surface of the tubular or channel shaped screen element by the vibratory motion and be discharged at the end of the vibratory separator. In a third aspect of the present invention, the screen elements of the vibratory separator are located in two or more vertically stacked decks and are fluidly connected to a feeder manifold that distributes unscreened material to the separate decks in series flow. This multiplies the effective length in the direction of flow of the screening area thus providing substantially higher screening efficiency and permitting screen elements of smaller opening size to be utilized on the lower decks without concern for damage or overloading due to the ability to screen out coarser solids on the upper decks.

In a fourth aspect of the present invention, use of multiple decks of screen elements permits all or a portion of the screened material passing the upper deck or decks to be directed to the lowest deck where screen elements have opening sizes slightly coarser than the upper screen elements and any solids rejected by the lowest deck thus provides an indication of failure of the upper screen elements or some other bypassing of unscreened material around the upper screen elements.

In a further aspect of the present invention, the screen elements and the feed manifold assembly will be attached to a housing providing a mechanism of conveying the oversize particles along the inner surface of the screen elements and facilitating the passage of the remaining liquid and undersize particles through the screen media.

In yet another separate aspect of the present invention, the vibratory housing together with the vibratory drive can be tilted up or down depending upon the process conditions.

Operator safety is increased because the individually replaceable screen elements are smaller, lighter and easier to install or change than the replaceable screen elements used on prior art vibrating separators.

By using vacuum or pressure differential to draw air or other gas through the screen elements in the same direction as the liquid portion normally flows, recovery of the liquid portion and discharge of drier oversize solids is achieved. A substantially larger screening area per unit area of installed space and improved multiple deck vibratory separator performance is provided. A substantially larger screening area per unit area of installed space is achieved by utilizing non-planar screen elements to increase screen surface area in contact with the process fluid and thus improving separator performance. The increased screening capacity results in significant space savings, cost savings and improved performance compared to prior art vibrating separators.

The dryness of the oversize or otherwise rejected solids is improved due to the tumbling action imparted to the rejected solids due the conveying force of the vibration on a tubular or channel shaped screen element.

DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the present invention, reference should be had to the following drawings in which like parts are given like reference numerals and wherein:

Figure 1 is a cutaway side view showing parallel feed to three decks of the preferred embodiment of the invention;

Figure 2 is a discharge end view of the device of Figure 1 ;

Figure 3 is a section view of a device of the preferred embodiment of the present invention showing drainage of screened material to the sump when multiple decks are fed in parallel;

Figure 4 is a cutaway side view of a device of an alternate preferred embodiment of the present invention showing series feed to three decks with progressively finer screen elements installed on lower decks;

Figure 5 is cutaway side view showing feed to three decks with coarser screen elements selected and installed on the lowest deck to indicate oversized or unscreened material is not being rejected by the screen elements in the upper decks; Figure 6 is a cutaway side view showing the variation of deck angle;

Figure 7 is a cutaway side view showing the method of distributing unscreened material to two or more decks in parallel;

Figure 8 A is a side view and Figure 8B is end view of a tubular screen element constructed of multiple screen media layers with a smooth (non-pleated) screening surface;

Figure 9A is a side view and Figure 9B end view of a tubular screen element constructed of multiple screen media layers with a pleated screening surface;

Figure 10A is a side view and Figure 10B is an end view of a tubular screen element constructed of multiple screen media layers with a discharge restriction to increase the pool of unscreened material retained in the screen element in order to increase the pressure differential across the screen and increase the screen area in contact with unscreened material;

Figure 11 A is a cutaway side view and Figure 1 IB is an end view of a screen element in which plastic material has been impregnated into the inner diameter of the tube to force the unscreened material to follow a non-linear path thus increasing solids dryness;

Figure 12 is side view of a screen installed in the vibrating basket showing the conical inlet nozzle and the conical tube retainer on the discharge end. The tube is clamped to the basket by "bayonet style" retainers for ease of tube element installation or removal;

Figure 13 is a cutaway side view of a tubular screener with rotating housing showing parallel feed;

Figure 14 is a discharge end view of tubular screener of Figure 13 with rotating housing; Figure 15 is a cutaway side view of a tubular separator with rotating housing showing series feed; Figure 16 is an isometric view showing one replaceable screen element having a pre-formed cross sectional geometry positioned above a porous channel designed with a similar cross sectional geometry to mate with and retain the screen element in the shape of the porous channel;

Figure 17 is cutaway side view of a vibratory separator utilizing channel shaped screen elements that have a semi-circular cross section;

Figure 18 is an end view of the device in Figure 17;

Figure 19 is side view, partially cutaway, of a single deck shaker utilizing channel shaped screen elements with one arrangement of side by side screen elements on the feed end and one arrangement of side by side screen elements on the discharge end;

Figure 20 is a discharge end view of the device in Figure 19 with the feed tank removed for clarity;

Figure 21 is an isometric view showing one replaceable screen element that is flat (not preformed) positioned above a porous channel that has been designed with a cross sectional geometry and length to mate with and retain the screen element in the shape of the porous channel;

Figure 22 shows an alternative method of retaining channel shaped screen elements within the porous channels.

Figures 23A, 23B and 23C illustrate a method of pre-forming screen elements.

Figure 24A is a top view of an unformed non-pleated screen element shown partly in cut line.

Figure 24B is a cross-sectional view of Figure 24A taken along section lines 8-8 of Figure 24A. Figures 24C, 24D, 24E, 24F, 24G and 24E illustrate alternative pattern impregnations associated with 24A.

Figure 25A is a top view of an unformed pleated screen element shown partly in cut line;

Figure 25B is a cross-sectional view of Figure 25 A taken along section lines 9-9 of Figure

25A.

Figure 26 illustrates a method of retaining screen elements within the porous channel; and

Figure 27 illustrates an alternative method of retaining screen elements within the porous channel.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Figure 1 illustrates a vibratory screen separator 1 of the preferred embodiment of the present invention. Separator 1 includes a base that also serves as a sump 10 upon which a vibratory housing 12 is resiliently mounted on springs 14 [FIGURE 2] that serve as vibration isolators. The housing 12 is a vertically stacked multiple deck design. The screening surface of each deck is created by an arrangement of side by side tube shaped screen elements 24 with unscreened material 100 flowing into the inside of the tube shaped screen elements 24. The resilient mounting of the housing 12 is provided by springs 14 [FIGURE 2]. The housing 12 is driven by a vibratory drive such as a pair of motion generators 16 connected to the housing 12 as is known in the art. A feed tank 18 is mounted on base 10 and is fluidly connected to a stationary feed distribution weir 20. The feed tank 18 presents material into the stationary feed distribution weir 20. The stationary feed distribution weir 20 includes a feed nozzle 21 that delivers fluid to a multiple hopper feed manifold 23 as discussed in more detail below. Each of the plurality of hoppers 15, 17, 19 includes multiple feed nozzles 22, 33, 37 with each nozzle fluidly connected to a screen element 24. Preferably, the screen element 24 is tubular shaped. The screen elements 24 are arranged substantially horizontally in preferably one or more decks 31, 35, and 39 having one end connected to the feed nozzles 22, 33, 37. The discharge ends 56 of the screen elements 24 are retained by the discharge end tube supports 60 at the discharge end 25 of the housing 12.

As illustrated in Figure 12, the feed nozzles 22 are tapered so that they will fit inside the elements 24 thus providing a liquid tight seal connection. The discharge end 56 of the screen element 24 is retained and supported by conical shaped discharge end retainers 62 attached to the discharge end screen support 60. The discharge end 56 of the screen element 24 fits inside of the discharge end retainer 62 allowing an unrestricted discharge of oversize solids (not shown in Figure 12). The nozzles 22, 33, 37 [FIGURE 1] and the discharge end retainers 62 are made of resilient material to prevent leakage around the screen elements 24. Each deck 31, 35, 39 [FIGURE 1] of screen elements 24 will have an independent discharge end screen support 60 allowing the screen elements 24 to be replaced on each deck 31, 35, 39 [Figure 1] independently. The discharge end tube retainers 62 are adjustable within the discharge end screen support 60 to provide adequate force against the elements 24 for a positive retention. The diameter of the screen elements 24 can be between one to six inches, preferably between two to three inches. The number of screen elements 24 placed side-by-side can be up to twenty four or in some special cases even up to 50 when one-inch screen elements 24 are used and as low as three when six-inch screen elements 24 are used.

Figure 3 illustrates parallel fluid flow over three decks. Under each deck 31, 35, 39 [FIGURE 2] of screen elements 24 is a flow-back-pan 26 which directs the screened material 29 passing through each screen element 24 towards the feed end 11 of the housing 12. The screened material 29 then gravity flows to the sump 41 via the drain tubes 40. The drain tubes 40 are not required for the preferred embodiment. They may be omitted because the screened material 29 would flow between the feed nozzles 22, 33, 37 and gravity flow to the sump 41 anyway. The tubes are shown in order to better illustrate parallel flow. The oversize solids 13 exiting the screen elements 24 are directed over discharge lips 28, 30 and 32 at the various levels of the screen elements 24 into a rejects bin (not shown).

The screen elements 24 are constructed of one or more layers of screen media that has been formed into an open ended tubular shape with either smooth [FIGURE 8B] or corrugated screening surface [FIGURE 9B]. A circular cross sectional geometry of the screen element 24 [FIGURE 8B] is preferred. However, elliptical, rectangular, or any other similar geometric shape capable of containing fluid flow can be used. The screen media with the finest opening size 50 [FIGURE 8A] is placed on the inside diameter and the subsequent layers of screen media 51, 52 are progressively coarser towards the outside diameter. Any combination of screen media can be used in these screen elements 24. Adequate rigidity and resiliency is typically supplied by the coarsest outer layer 52 of the screen element 24.

Alternatively the rigidity or resiliency of the screen element 24 may be increased by pleating the screen media [FIGURE 9A] or by using a porous metal tube as the outermost layer 52. Additional resiliency or rigidity may be required for the screen elements 24 to withstand the solids loading, liquid loading, or the vibration produced by the motion generators 16 in some process conditions. The screen elements 24 can be replaced individually as required when the screen media wears or tears from the process conditions. The screen element 24 may further incorporate plastic impregnations or raised flow directors 63 on the inside diameter of the screen tube element 24 [FIGURE 11 A & 1 IB] to increase separation performance or aid solids conveyance.

L an alternate preferred embodiment illustrated in Figure 4, the flow-back-pans 26 and the feed hopper manifold 23 can be arranged to create series flow where all the unscreened material 100 enters the uppermost hopper 17 that directs fluid to the screen elements 24 on the top deck 31 first. The screened material 29 passing through the top deck 31 of screen elements 24 is then directed by the flow back pan 26 sequentially to the middle hopper 19 feeding the nozzles 33 on the middle deck 35 of screen elements 24. The screened material 29 passing through the middle deck 35 of screen elements 24 is directed to the lowest hopper 15 feeding the nozzles 37 of lowest deck 39 of screen elements 24. Series fluid flow permits screen elements 24 of smaller opening size to be utilized on the lower decks without concern for damage or overloading due to the ability to screen out coarser solids on the upper decks yielding a substantially higher screening efficiency. Although three decks are shown in Figure 4, additional decks can be added be employed and fed in series fluid flow.

In a third preferred embodiment illustrated in Figure 5, the lowest deck 39 is used to monitor the quality of the screened material 29 reporting downstream of the vibratory separator. The screen elements 24 selected for installation on the lowest deck 39 will preferably have openings that are larger than the openings in the screen elements 24 installed on the upper decks 31, 35 for the purpose of quality control rather than screening. This is accomplished by (A) feeding unscreened material 100 to the upper decks in parallel fluid flow and installing screen elements 24 with identical size openings on the upper decks 31, 35 or (B) feeding unscreened material to the upper decks in series flow with progressively finer screen elements 24 on decks 31, 35 above the lowest deck 39. (Only three decks are shown but more than three decks can be employed). In both Case A and Case B above, all or a portion of the screened material 29 from the upper decks 31, 35 is then directed to the lowest deck 39 that has screen elements 24 installed with openings larger in size than the openings in the screen elements 24 installed in the upper decks 31, 35. The lowest deck 39 rejects oversize solids 13 only in the event of a failure of the upper screen elements or when for other reasons unscreened material 100 reports with the screened material 29 from the upper decks 31, 35. The oversize solids 13 from the screen elements 24 installed on the lowest deck 39 can be discharged into, for example, a screw feeder 43 or similar device to segregate and collect oversize solids 13 thus providing indication via instrumentation or visual inspection that undesirable coarse solids 13 are reporting with screened material 29 downstream of the upper decks 31, 35.

As illustrated in Figure 6, it is also important to have the ability to adjust the angle of the housing 12 containing the screen elements 24 relative to a position of zero degrees 0 with respect to the horizon. A maximum up hill angle of plus five degrees should be sufficient to produce desired solids dryness. A slight downhill angle slight downhill angle of minus 3 degrees is desired to improve the conveyance of the oversize solids 13 retained inside the screen elements 24 toward the discharge end 25 of the housing 12.

As illustrated in Figure 7, the multiple hopper feed manifold 23 prevents unscreened material 100 from "short circuiting" or flowing preferentially through the set of screen elements 24 on the lowest deck 39 when feeding the decks 31, 35, 39 in parallel fluid flow. Overflow weirs 34, 36 are provided to ensure that flow of unscreened material 100 entering the multiple hopper feed manifold sequentially fills the uppermost hopper 17 first, then fills the middle hopper 19, and fills the lowest hopper 15 last. The outlet 21 of the overflow weir 20 directs unscreened material 100 first to hopper 17 which feeds the screen elements 24 on the first deck 31. If volume flowrate is sufficiently high, unscreened material 100 will overflow the uppermost spillover weir 34 to feed unscreened material 100 to the second hopper 17 of feed hopper manifold 23 thus resulting in unscreened material 100 entering the screen elements 24 on the second deck 35. If volume flowrate is sufficiently high, unscreened material 100 will overflow the middle spillover weir 36 to feed unscreened material 100 to the lowest hopper 15 of feed hopper manifold 23 thus resulting in unscreened material entering the screen elements 24 on the third deck 39. In case of an extremely high flowrates of unscreened material 100, the feed hopper manifold 23 can overflow the relief weir 38 so that the excess flow will go over the upper deck elements 24 providing a visual indication or instrumented alarm that an overflow condition exists. (Although three decks are shown, additional decks can be added be employed and fed in parallel fluid flow.)

Alternate methods to control the flow of unscreened material 100 to the various decks can be utilized. These may include but are not limited to restricting the flow of unscreened material 100 through the feed nozzles 22, 33, and 37 by varying the orifice sizes of the feed nozzle 22, 33, 37 with flow control valves, pulsating flow control valves, and other like devices.

As illustrated in Figure 10A and 10B, alternate methods can be utilized to improve the separation efficiency of the screen elements 24. By restricting the discharge diameter 48 [FIGURE 10B] of a screen element 24, the volume of unscreened material (not shown) retained in the screen element can be increased. The increased volume increases the hydrostatic pressure exerted by the unscreened material (not shown) on the inner diameter of the screen elements 24, thus forcing screened material (not shown) through the screen elements 24 at a higher rate. A restricting nozzle 55 [FIGURE 10A] is molded or bonded into the inner diameter of the discharge end 56 of the screen tube element 24. A truncated cone shape 59 forms the inner diameter on the upstream side 58 of the restricting orifice 55 permitting oversize solids (not shown) to convey out of the screen element 24.

A fourth preferred embodiment is illustrated in Figure 13 wherein a cylindrically shaped housing 92 rotates. Unscreened material is directed in parallel flow through one or more concentric circular arrays 71, 75, 79 [FIGURE 14] of tubular screen elements 24. It is preferred that the housing 92 be simultaneously vibrated by a vibration module 16 while rotating although vibration is not necessary for separation in some processes. The screen elements 24 are arranged in concentric circular arrays 71, 75, 79 [FIGURE 14] that increase in diameter from the centerline of the cylindrical housing 92 rather than in the horizontal decks of the previously discussed embodiments. The housing 92 is supported by rolling elements 76 [FIGURE 14] that enable the housing to rotate at speeds below critical speed in order to allow the unscreened material 100 to remain in the bottom of feed hoppers 95, 97, and 99. A stationary (non-rotating, non-vibrating) feed tube 70 introduces unscreened material 100 into the feed hopper manifold 73 that directs unscreened material 100 first to the innermost feed hopper 95 that is fluidly connected to the screen elements 24 of the innermost circular array 71. The unscreened material 100 is prevented from "short circuiting" or preferentially flowing through the screen elements 24 fluidly connected to the middle feed hopper 97 or the outermost hopper 99 by the design of the feed hopper manifold 73. The multiple hopper feed manifold 73 is constructed so that unscreened material 100 overflows in a cascade fashion sequentially from the innermost hopper 95 to the middle hopper 97 to the outermost hopper 99 as required to handle increasing feed rate of unscreened material 100. The unscreened material 100 flows through the stationary feed tube 70 and enters the innermost feed hopper 95 first. The screen elements 24 on the innermost array 71 are fluidly connected to the innermost hopper 95 and will screen all the unscreened material 100 until a feed rate increase reaches "spillover point" causing unscreened material 100 to overflow the innermost weir 94 and enter hopper 97. The screen elements 24 on the middle array 75 are fluidly connected to the middle hopper 97 and will screen the unscreened material 100 reporting to the middle hopper 97 until further feed rate increases reach a "spillover point" causing unscreened material 100 to overflow the middle weir 96 and enter hopper 99. L case of an extremely high flow, the feed hopper manifold 73 can overflow the relief weir 98 and excess unscreened material 100 will flow over the innermost array of screen elements 24 and over flow the discharge end 93 of the housing 92 thus providing indication via instrumentation or visual inspection that a "flooding condition" exists and unscreened material 100 is being lost with the oversize solids 13. Flowback pans 77, 78 direct screened material 29 towards the feed end 91 of the housing 92 where the screened material 29 gravity flows between the feed nozzles 22, 33 respectively and collects in the inner diameter 89 of the housing 92. (Although three concentric arrays are shown, additional arrays can be added be employed and fed in parallel fluid flow.) A stationary evacuation tube 72 removes the screened material 29 from the inner diameter 89 of the housing 92 as it collects in the feed end 91. Evacuation of the screened material 29 via the evacuation tube 72 will require a pump (not shown) capable of overcoming the suction lift. A slight vacuum created by the pump (not shown) will assist with fume containment and improve separation. Alternately, the screened material could gravity discharge from the housing via nozzles (not shown) that penetrate the wall of the housing 92 at the feed end 91 allowing screened material 29 to report to the sump 41 [FIGURE 15]. The housing 92 is rotated by belt 80 or chain drive attached to the external drive motor 90. Alternately, the housing can be rotated by a drive motor (not shown) attached to one or more of the rotating elements 76 [FIGURE 14] that support and center the housing 92. Alternately, rather than rotating the housing 12, the housing 12 can be oscillated forward and back through an angle approaching 360 degrees by the motor 90 attached to the housing 12 to effect the same screening separation. L both the case of rotation and the case of oscillation, vibration is preferred but not required. i a fifth prefeπed embodiment is illustrated in Figure 15, unscreened material 100 is directed in series fluid flow through one or more circular arrays 71, 75, 79 of tubular screen elements 24. Series flow is accomplished by isolating the middle feed hopper 97 and the outermost feed hopper 99 from the stationary feed tube 70 that introduces unscreened material 100 into the innermost feed hopper 95 which is fluidly connected to the screen elements 24 of the innermost circular array 71. L series fluid flow, all of unscreened material 100 is directed first through the screen elements 24 fluidly connected to the innermost hopper 95. Screened material 29 that passes through the screen elements 24 fluidly connected to the innermost hopper 95 is directed by a flow back pan 77 to feed hopper 97. Feed hopper 97 is fluidly connected to the screen elements 24 of the middle circular array 97. Screened material 29 that has passed through the screen elements 24 fluidly connected to the middle feed hopper 97 is then directed by the flow back pan 78 to feed hopper 99. Feed hopper 99 is fluidly connected to the screen elements 24 of the outermost circular array 79. Screened material 29 that has passed through the screen elements 24 fluidly connected to the feed hopper 99 then exits the housing through the stationary evacuation tube 72 previously discussed or by the non- preferred alternative of exiting through nozzles (not shown) that penetrate the housing 92 allowing screened material 29 to report to the sump 41. The series flow arrangement wherein the innermost array 71 [FIGURE 14] of screen elements 24 have larger size openings than the middle array 75 [FIGURE 14] of screen elements 24 and the outermost array 79 [FIGURE 14] of screen elements 24 provides sequential solids removal based on particle size to prevent the coarse solids from damaging the finer screen elements 24 installed on the middle and outermost arrays 75, 79, thus increasing screening element life for the finer screen elements 24 and improving separation. The series flow arrangement where all circular arrays of screen tube elements 24 have equal coarseness is not preferred but will increase the rejection rate of oversized solids (not shown) as a result of redundant screening. As previously discussed in either series flow or parallel flow, the lowest deck 79 [FIGURE 14] can have screen elements 24 selected so that the opening size is larger than the opening size of the screen elements 24 installed in the inner arrays 71, 75. All or a portion of the flow of screened material 29 passing the inner arrays 71, 75 can be directed to the outermost array 79 in order to monitor quality of the separation process as previously discussed. This embodiment can have one or more separate decks, preferably one to four.

It is also important to have the ability to adjust the angle of the housing 92 with the screen elements 24 relative the horizontal position shown in Figure 13 of 0 degrees. A maximum up hill angle of plus five degrees [FIGURE 13] should be sufficient to produce desired solids dryness. A slight downhill angle [FIGURE 13] of minus 3 degrees may be needed in some cases to improve the conveyance of the oversize solids within the screen elements 24 towards the discharge end 93 of the housing 92.

In the sixth preferred embodiment, channel shaped screen elements 240 [FIGURE 16] may replace tube shaped screen elements 24. As illustrated in Figure 16, a screening surface is created when a pliable and resilient screen element 240 constructed of one or more layers of screening media that have been joined into an assembly is inserted in a rigid porous channel 250. For clarity, in Figure 16 the screen element 240 is shown to be pre-formed into the shape of the porous channel 250 and positioned a distance 235 above the rigid porous channel 250 as if it is ready to be inserted. However, a flat non-preformed screen elements 240 [FIGURE 21] may also be employed. If pre-formed, the screen element 240 [FIGURE 16] must have a pre-formed radius equal to or greater than the radius of the porous channel 250 in order to utilize the resiliency of the screen element 240 to form fit to the porous channel 250. The porous channel 250 is formed to preferably a semi-circular shape; however, other shapes can be utilized. For example, the cross sectional geometry can be "V" shaped, semi-circular, semi-elliptical, catenary, hyperbola, or any other similar geometric shape capable of channeling fluid flow The preferred radius of the channel is between one and three inches. Other dimensions can be used depending on the process requirements.

Figure 16 shows the preferred semi-circular shape of the porous channel 250. Each porous channel 250 will have short folds 230 directed inwards from both sides. The screen element 240 is fabricated so that the curved perimeter 242 of the screen element 240 fits tightly to the curved perimeter 252 beneath the short inward folds 230 of the porous channel 250. The screen element 240 is forced into the porous channel 250 by placing one long edge 244 ^"of the screen element 240 under the short inward fold 230 on one side of the rigid porous channel 250 and pushing the rest of the screen element 240 into the channel 250 and securing the opposite long edge 244 of the screen element 240 under the opposite short inward fold 230. The screen element 240 will conform to the shape of the porous channel 250 thus being supported by the porous channel 250 due to the (a) resiliency of screen element 24, (b) due to the liquid and solids loading from the unscreened material (not shown), and (c) differential pressure (not shown) used to motivate liquid or gas through the layer or layers of screen element 240 in the direction that screened material normally flows through the screen element 240. (d) compressive forces created by forming the screen media into the shape of the curved perimeter 242 of the porous channel 250. Li the case of wire mesh being employed as screening media, the wires, not shown, that run parallel to the curved perimeter 242 of the screen element 240 are forced into compression to match the curved perimeter 252 of the porous channel 250 beneath the inward folds 230. The screen elements are prevented from being conveyed by vibratory motion out the porous channel 250 by the mating of retention tab 200 on the screen element 240 to the retention slot 220 on the porous channel 250. Figure 22 illustrates an alternative screen element retention mechanism wherein a rigid tab 81 is permanently joined to the discharge end of each porous channel 250 to prevent the screen element (not shown) from conveying out of the porous channel 250 due to the vibratory motion. The retention tab 81 is positioned immediately below the short inward fold 230 on the porous channel to prevent interference with discharge of rejected solids (not shown). The clip 160 is small enough to not interfere with end loading of the screen element 240 (not shown) into the porous channel 250.

The screen element 240 is additionally restrained from movement by the lamination or bonding of retention tabs 200 to the long edges 244 of the screen element 240. The retention tabs 200 fit into one or more slots 220 that have been cut or formed in the short inward folds 230 of the rigid porous channel 250.

Figure 17 shows an alternate embodiment wherein a multi-deck separator utilizes channel shaped screen elements 240 rather than tube shaped screen elements 24 [FIGURE 1] for parallel flow over three decks 31, 35, and 39. Figure 18 shows the discharge end view of the multi-deck separator in Figure 17 utilizing channel shaped screen elements 240. Substitution of channel shaped screen elements 240 enables the vertical spacing 260 [FIGURE 18] between decks 31, 35, and 39 to be diminished thus lowering the overall height of the vibratory separator or enabling additional decks to be added for more screening capacity. The side by side horizontal spacing 270 [FIGURE 18] should be minimized to maximize screening area. Although three decks are shown in Figures 17 and 18, additional decks can be added or employed. This embodiment can be used with both the parallel feed [FIGURE 1] and series feed [FIGURE 4] configurations previously discussed for tubular shaped elements. Similarly, the lowest deck 39 [FIGURE 18] can have screen elements 240 [FIGURE 17] selected so that the opening is larger in size than the openings in the screen elements 240 installed in the upper decks 31, 35. All or a portion of the flow of screened material 29 from the upper decks 31, 35 can be directed to the lowest deck 39 in order to monitor quality of the separation process as previously discussed. This embodiment can have one or more separate decks, preferably one to four.

Figure 19 shows an alternative embodiment wherein a vibratory separator utilizes multiple arrangements of side by side channel shaped screen elements 240 in a single deck. As illustrated, two arrangements of side by side channel shaped screen element 240 are located in the same plane so that the discharge end 25 of one arrangement of side by side screen elements abuts the feed end 11 of the next arrangement of side by side screen elements 240 thus forming a longer screen deck and more screening area. This configuration will provide a much larger screening area resulting in a higher capacity. A single deck may be lengthened by abutting up to five or more (two are shown in Figure 19) multi-element arrays of channel shaped screen elements 240 for additional screening efficiency and even higher capacity. Figure 20 illustrates the discharge end of a single deck vibratory screener described above. Channel shaped screen elements 240 are inserted easily into porous channels 250 [FIGURE 16] from above thus facilitating individual replacement of screen elements 240 on a single deck without need for an unobstructed space on the discharge end to extract or insert screen elements 240.

As illustrated in Figures 23 A, 23B, 23C pre-forming screen elements to the channel geometry may need to take place over a press 180 to prevent distortion of some screening media when the screen elements 24 are inserted into the channels 250. The cross sectional geometry of the male section of the press 180 will be the same shape but of a slightly larger diameter or width than the porous channel for which the press 180 is intended to make screen elements 20. A female section 185 of the press is used to form the screening media into the desired geometry to provide the resilient form fitting characteristics of the screen elements when inserted into the porous channel 250. Single or multiple layer screening media can be formed into screen elements 24. When constructing layered screen elements, the finest screening media, such as middle layer 86, is positioned over the male section of the press first with subsequent and coarser layers of screening media, such as screening media 83, following to the outside. A layer 85 of plastic laminate or glue may be used between the finer screening media and a coarser screening media. Capping or impregnation of the screen element edges may also take place while the screening media is formed in the press.

As illustrated in Figures 24A and 24B and 25A and 25B unformed screen elements may also be used. Figure 24A is a non-pleated screen element comprising of one or more layers of screening media. Figures 24C through 24G detail alternate configurations of impregnated plastic 85. Figure 25 is a pleated screen element comprising of one or more layers of screening media. Two layers are shown in both figures for sake of clarity. The finest screening media, such as middle layer 86, will be the innermost layer so that unscreened material passes through the finest screening media first. The other layer 83 will be coarser screening media to add strength and rigidity to the screen element 24. The long edge 101 of the screen element 24 is not a conveying or screening surface and may be capped by hemming the screening media, by a crimped sheet metal edge, rubber or a plastic or epoxy impregnation. The U shaped or short edge 120 will need to be non-obstructive to the flow of oversize particle or carrier fluid and can be capped by hemming or by plastic or epoxy impregnation. This capping provides a seal preventing solids from collecting between the layers of wire cloth.

Figure 26 illustrates the retention clip 160 that is permanently bonded to each porous channel 250 at the outlet of the channel 250 to prevent the screen element (not shown in Figure 26) from conveying out of the channel 250 due to the vibratory motion. The clip 160 is positioned immediately below the flange 130 on the porous channel 250 to prevent interference with solids conveyance that takes place on the lower surface of the channel 250. The clip 160 is small enough to not interfere with end loading of the screen elements 24 into the porous channel 250. Figure 26 also shows the feed end 140 wherein no clip 160 is required.

Figure 27 indicates an alternative screen element design wherein thin strips 200 are attached to the screening media in preformed screen elements 24. The strips 200 are positioned on the screen element to match notches 220 in the flanges 130 on the porous channels 250. The strips 200 serve two purposes by (a) retaining the screen element 24 within the channel 250, and (b) to facilitate screen element 24 removal.

Accordingly, an improved screen system is disclosed for increasing the available screening area. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concept herein.

Claims

CLAIMSWhat is claimed as invention is:

1. A screen separator using a drive, comprising: abase; a housing driven by the drive; a screen assembly; said housing and said assembly mounted on said base; a feed tank, said feed tank mounted on said base; a feed hopper manifold attached to said housing; said feed tank being in fluid communication with said feed hopper manifold.

2. The screen separator of claim 1 , wherein said feed tank includes a weir.

3. The screen separator of claim 2, wherein said weir has an outlet nozzle.

4. The screen separator of claim 2, wherein said feed hopper manifold includes multiple tier feed hoppers mounted on said base and at least one of said feed hoppers positioned to receive fluid from said weir.

5. The screen separator of claim 4, wherein said weir has an outlet nozzle and said outlet nozzle is positioned to deliver fluid from said outlet nozzle to at least one of said feed hoppers.

6. The screen separator of claim 5, wherein there are at least two feed hoppers, one of said feed hoppers in fluid communication with said other feed hopper and said feed tank.

7. The screen separator of claim 1 , wherein the drive includes a motion generator.

8. The screen separator of claim 1, wherein said resilient mount is resilient and includes a spring.

9. The screen separator of claim 1, wherein said base includes a sump.

10. The screen separator of claim 1, wherein said screen assembly includes channel shaped screen elements.

11. The screen separator of claim 1, wherein said screen assembly includes tubular shaped screen elements.

12. The screen separator of claim 1, wherein said feed hopper manifold includes at least one feed hopper having a nozzle connected to said screen assembly.

13. The screen separator of claim 12, wherein said screen assembly has at least one screen element, said screen element being shaped to have an interior and said nozzle being tapered to be inserted into said interior of said screen element at one end of screen assembly.

14. The screen assembly of claim 13, wherein said insertion forms a seal between said screen element and said nozzle.

15. The screen separator of claim 13, wherein said housing has a discharge end with at least one support and said screen element is supported at said discharge end of said housing by said support.

16. The screen separator of claim 15, wherein said support forms a seal with said screen element.

17. The screen separator of claim 1, wherein said housing is adjustable in angle with respect to a horizontal position.

18. The screen separator of claim 17, wherein said angle is between an uphill angle of five degrees and a downhill angle of minus three degrees.

19. The screen separator of claim 1, wherein said screen assembly includes screens mounted adjacent each other and form screen decks, said screen decks being cylindrical in shape and said housing is cylindrical in shape; said screen assembly being mounted in said housing and said screen decks being rotatably mounted on said base.

20. The screen separator of claim 1, wherein said housing is resiliently mounted on said base.

21. The screen separator of claim 20, wherein each of said screen decks or arrays are substantially coaxial with said center line of said housing.

22. The screen separator of claim 21, wherein said feed tank is in fluid communication with said screen deck or array closest to said centerline of said housing.

23. The screen separator of claim 22, wherein said elements of said decks or arrays have larger openings in the screen media in said inner aπay then said outer array.

24. The screen separator of claim 21 , wherein said screen decks or arrays are concentric.

25. The screen separator of claim 24, wherein said feed hopper fluid communication being in series through said decks.

26. The screen separator of claim 25, wherein said feed hopper fluid communication being in parallel through said decks.

27. The screen separator of claim 1, wherein there is a controlled atmosphere in said housing.

28. The screen separator of claim 27, wherein said atmosphere is at a slight vacuum.

29. A screen separator using a vibratory drive, comprising: a base; a vibratory housing driven by the drive; a screen assembly; said housing and said assembly resiliently mounted on said base; wherein said screen assembly includes screen elements, said screen elements arranged in decks of elements, each of said decks being arranged to have an outlet, each of said outlets being separately supported at said outlet; said screen elements being individually replaceable on said screen assembly of said element.

30. The screen separator of claim 29, wherein each of said elements of one of said decks has a screen media with the same opening size as other screen media on said deck and each of said decks having different sized media openings, with the largest openings being on the upper layer.

31. A screen separator for separating solids using a vibratory drive, comprising: a base; a vibratory housing driven by the drive; a screen assembly; said housing and said assembly resiliently mounted on said base; wherein said assembly includes at least one screen element in the form of a single flow directing channel.

32. The screen separator of claim 31, wherein said flow directing screen element, is a tubular shaped screen element.

33. The screen separator of claim 31, wherein said flow directing screen element is a channel shaped screen element.

34. The screen separator of claim 31, wherein there is a bottom level of said screen assemblies.

35. The screen separator of claim 31, wherein said elements are adjacent and separated from each other a sufficient distance to permit flow between them.

36. The screen separator of claim 31, wherein said flow directing screen elements are arranged in decks and there are six to fifty of said elements for each of said decks.

37. The screen separator of claim 36, wherein said base includes a sump and there is further included a flow back pan for each of said decks, said flow back pan being canted to direct fluid to said next deck.

38. The screen separator of claim 36, wherein said base includes a sump and there is further included a flow back pan for each of said decks, said flow back pan being canted to direct fluid to said sump.

39. A screen separator using a vibratory drive, comprising: a base; a vibratory housing driven by the drive; a screen assembly; said housing and said assembly resiliently mounted on said base; wherein said assembly includes more than two flow directing shaped screen elements.

40. The screen separator of claim 39, wherein said fluid connection is in series.

41. The screen separator of claim 39, wherein said flow directing elements are tubular shaped.

42. The screen separator of claim 39, wherein said flow directing elements are channel shaped.

43. The screen separator of claim 39, wherein said flow directing elements are connected in parallel.

44. The screen separator of claim 39, wherein said screen elements being individually replaceable.

45. The screen separator of claim 44, wherein said elements are tubular in shape.

46. The screen separator of claim 44, wherein said elements include at least one layer of screen media.

47. The screen separator of claim 45, wherein said layers of screen media are joined together.

48. The screen separator of claim 44, wherein said screen elements being in the form of a single flow directing channel.

49. The screen separator of claim 48, wherein said screen media is formed from a formed element.

50. The screen separator of claim 48, wherein said screen media is formed from a single tube laser cut or otherwise machined to created desired opening size in said tube.

51. The screen separator of claim 1, wherein the drive is a vibratory drive and said housing is a vibratory housing, said housing and said assembly being resiliently mounted on said base.

52. A screen for use with a screen separator comprising a multiple s'et of independent flow directing screen elements.

53. The screen of claim 52, wherein said element is shaped in the form of a channel.

54. The screen of claim 52, wherein said element is shaped in the form of a tubular element.

55. The screen separator of claim 48, wherein said formed element is a formed element.

56. A screen assembly, for use with a vibratory separator to screen material and convey solids, comprising: a retro-fit carriage, said carriage mounted in the vibratory separator; a set of porous channels, said channels being attached to each other and to said carriage and said channels being aligned parallel to the direction of the conveyance of the solids; and a screen element mounted on at least one of said channels.

57. The screen assembly of claim 56, wherein said carriage is a structural frame.

58. The screen assembly at claim 56, wherein said channels are attached such that the screened material does not bypass said screen element.

59. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is half-circular.

60. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is half-ellipsoid.

61. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is catenary.

62. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is hyperbolia.

63. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is rectangular.

64. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is triangular.

65. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is U-shaped.

66. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is semi-circular.

67. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is V-shaped.

68. The screen assembly of claim 56, wherein said channels have a cross-sectional geometry that is a geometric shape exclusive of straight lines.

69. The screen assembly of claim 56, wherein said screen element includes at least one layer of screening media.

70. The screen assembly of claim 69, wherein said screening media includes at least two screens bonded to each other.

71. The screen assembly of claim 69, wherein said screen elements are preformed to conform to the geometry of said channels.

72. The screen assembly of claim 56, wherein said screen elements are removably mounted on said channels.

73. The screen assembly of claim 56, wherein said porous channel has a cross-sectional geometry selected with said screen element to optimize the surface area available for screening the screen material.

74. The screen assembly of claim 56, wherein said porous channel has an available open area pattern selected to maximize the open area.

75. The screen assembly of claim 56, wherein said porous channel include a screen retention mechanism, said screen retention mechanism preventing the movement of said screen element within said channel.

76. The screen assembly of claim 56, wherein said screen element is resilient.

77. The screen assembly of claim 56, wherein said screen element has more than one screening media, said screening media permitting different sizes of material to pass through the screening media.

78. The screen assembly of claim 56, wherein said porous channel and said screen element both have cross-sectional areas, said cross-sectional areas tapering along the length of said porous channel and said screen element.

79. The screen assembly of claim 56, wherein said carriage is constructed of a stainless steel or suitable material.

80. The screen assembly of claim 56, wherein said porous channel has a diameter and said diameter ranges from 1/2 inch to 10 inches.

81. The screen assembly of claim 56, wherein said porous channel has a length, said length being in a range from 12 inches to 60 inches.

82. A modifier, for use with vibratory separator to screen material and convey solids, comprising: a carriage, said carriage mounted in the vibratory separator; and a set of porous channels, said channels being attached to each other and to said carriage and said channels are aligned parallel to the direction of the conveyance of the solids.

83. The screen assembly of claim 82, wherein there is included a screen element mounted on at least one of said channels.

84. The screen assembly of claim 56, wherein said porous channel includes a blocking mechanism to block outward movement of said screen element.

85. The screen assembly of claim 84, wherein said blocking mechanism includes clips formed across the top opening of the channel.

86. The screen assembly of claim 85, wherein said clips form an angle defined by the lower surface of said clip and the vertical tangent of said channel inner surface which is in the range of 80° to 100°.

87. The screen assembly of claim 85, wherein said clips form an obtuse angle, said angle defined by the lower surface of said clip and the vertical tangent of said channel inner surface.

88. The screen assembly of claim 56, wherein said screen element has two or more layers of screening media, said screening media ranging from finest to coarsest and said finest screening media being placed on the topside of said porous channel.

89. The screen assembly of claim 56, wherein said screen element is preformed to the same shape as said channel but with slightly larger width than said channel.

90. The screen assembly of claim 56, wherein said porous channels have notches and said screen elements have strips and said screen element mounts in said channels so that said strips are adjacent and inserted into said notches.

91. A screen element, for use with a vibratory separator to screen material and convey solids, comprising: a screen, said screen having a width of 10 inches or less.

92. A screen element, for use with a vibratory separator to screen material and convey solids, comprising: a screen, said screen having tabs to hold screens in place relative to the vibratory separator.

93. A screen element for use with a vibratory separator to screen material and convey solids, comprising: a first screen; a second screen; a deformable material, said deformable material mounted between said first screen and said second screen; said first screen and said second screen being attached to said bonding material by the process of forming while heated, said forming eliminating air bubbles between either of said screens and said bonding material.

94. The screen separator of claim 34, wherein at least a portion of said bottom level indicates a fault in said screen assemblies on any of said other levels of said screen assemblies when there is a presence of solids on said portion of said bottom level.

95. The screen separator of claim 49, wherein said formed element is moulded.

96. The screen of claim 52, wherein said element is relatively small, whereby small sections of a screening surface are independently removable.

97. A screen element, for use with a vibratory separator to screen material and convey solids, comprising: at least two layers of screening media, wherein a portion is non-conveying or screening; said portion being capped to form a seal preventing solids from collecting between said layers.

98. A screen element, for use with a vibratory separator having a porous channel to screen material and convey solids, comprising: at least one layer of screening media; thin strips of material, said strips positioned on said screening material, said strips positioned to engage the porous channel.