CA1100828A - Plastic-wire cloth and method of making the same - Google Patents
Plastic-wire cloth and method of making the sameInfo
- Publication number
- CA1100828A CA1100828A CA283,943A CA283943A CA1100828A CA 1100828 A CA1100828 A CA 1100828A CA 283943 A CA283943 A CA 283943A CA 1100828 A CA1100828 A CA 1100828A
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- Prior art keywords
- wire
- fabric
- cloth
- plastic
- woven
- Prior art date
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Abstract
PLASTIC-WIRE CLOTH AND METHOD
OF MAKING THE SAME
Oliver C. Steger - Hanover, PA
William B. Krebs - Hanover, PA
Abstract of the Disclosure A plastic-wire cloth in which the body of the cloth is composed of woven wire elements. The woven elements are encapsulated by a plastic film which is of uniform thickness and is uninterrupted throughout. The plastic-wire fabric is produced by passing the woven wire through apparatus which deposits a powdered resinous material on the wire by providing a cloud of ionized powder in fluidized beds on opposite sides of the path of the wire cloth through the apparatus. The wire with the powder deposited thereon is passed through a curing oven which integrates the powdered material into a continuous unbroken film.
OF MAKING THE SAME
Oliver C. Steger - Hanover, PA
William B. Krebs - Hanover, PA
Abstract of the Disclosure A plastic-wire cloth in which the body of the cloth is composed of woven wire elements. The woven elements are encapsulated by a plastic film which is of uniform thickness and is uninterrupted throughout. The plastic-wire fabric is produced by passing the woven wire through apparatus which deposits a powdered resinous material on the wire by providing a cloud of ionized powder in fluidized beds on opposite sides of the path of the wire cloth through the apparatus. The wire with the powder deposited thereon is passed through a curing oven which integrates the powdered material into a continuous unbroken film.
Description
llOQ8Z8 The present invention relates to irnprovements in the manufacture of wire cloths and, in particular, relates to an improved plastic-wire cloth and a method of making the same.
The invention is particularly applicable to flexible wire cloth which is woven in continuous lengths on wire fabric looms.
Prior to the present invention, flexible wire cloth fabricated either from rnetallic or non-metallic wires, has been used for insect screening, filtering and similar uses. In addition, screening has been fabricated from textile filaments, lo usually monofilaments of nylon or saran or coated multifilaments of glass fiber. While such plastic screen fabrics have many desirable characteristics, the consurning public appears to prefer wire cloth for use as insect screening.
There have been attempts to improve the characteristics of wire cloth in order to incorporate many of the desirable features of plastic screening, but such attempts have not been entirely successful commercially. However, wire cloth is presently available which is galvanized or zinc-dipped, or painted to protect the wire elements from corrosive constituents in the environment where the cloth is used. The treatment of wire cloth in the latter fashion is expensive and time-consuming, and requires severe measures to avoid polluting the atmosphere and the waterways. The present invention provides a preferable alternative to such treatment.
The present invention combines the desirable character-istics of plastic and wire cloth screening by providing a plastic-wire cloth screening consisting of a base fabric of conventional wire coL~ponents in which the wire components are protected from corrosive elernents by encapsulating the components in plastic to ~ -provide an exposed surface consisting of an unbroken plastic film protecting the wire components from corrosive atmospheres,
The invention is particularly applicable to flexible wire cloth which is woven in continuous lengths on wire fabric looms.
Prior to the present invention, flexible wire cloth fabricated either from rnetallic or non-metallic wires, has been used for insect screening, filtering and similar uses. In addition, screening has been fabricated from textile filaments, lo usually monofilaments of nylon or saran or coated multifilaments of glass fiber. While such plastic screen fabrics have many desirable characteristics, the consurning public appears to prefer wire cloth for use as insect screening.
There have been attempts to improve the characteristics of wire cloth in order to incorporate many of the desirable features of plastic screening, but such attempts have not been entirely successful commercially. However, wire cloth is presently available which is galvanized or zinc-dipped, or painted to protect the wire elements from corrosive constituents in the environment where the cloth is used. The treatment of wire cloth in the latter fashion is expensive and time-consuming, and requires severe measures to avoid polluting the atmosphere and the waterways. The present invention provides a preferable alternative to such treatment.
The present invention combines the desirable character-istics of plastic and wire cloth screening by providing a plastic-wire cloth screening consisting of a base fabric of conventional wire coL~ponents in which the wire components are protected from corrosive elernents by encapsulating the components in plastic to ~ -provide an exposed surface consisting of an unbroken plastic film protecting the wire components from corrosive atmospheres,
-2-110~8Z8 when used as screening and/or corrosive solutions when used in industrial filtering applications.
The improved screening of the present invention is fabricated by weaving a flexible wire fabric and applying a plastic film to the components of the fabric after weaving by coating the woven components with a powdered resin and curing the resin in place on the woven screening to generate an un-interrupted plastic film on the components.
In particular, the powdered resinous material is deposited on the woven wire by electrostatic deposition which is readily controlled so as to effectively deposit an uninter-rupted coating upon the component which, when cured, forms an integral film thereon.
Thus the present invention provides a method of making a plastic-wire cloth comprising the steps of weaving a continuous length of fabric of wire elements of electrically conductive material, passing said woven~wire fabric first through an alkaline bath to remove the dirt, grease or other foreign matter from the surface of the wire elements, second through a spray rinse to complete the cleansing, third through a drying oven to dry the woven-wire fabric, and fourth from said oven through a cloud of charged particles of a film-forming powdered resinous material at a rate of feed to deposit a continuous layer of particles on the wire elements of said fabric in a thickness suitable for forming a continuous film, and then heating said continuous length of woven-wire fabric to heat-flow said particulate material into a continuous unbroken integral film which is cured and encap-sulates the individual wire elements of said fabric.
. .
...
-:
~' ~ ' ..
The present invention provides a plastic-wire cloth which is flexible and rnay readily bend without fracturing the film or causing the filr~ to flake. The encapsulated components provide a substantially improved strength-to-weight ratio enabling either the use of a lighter cloth for a comparable purpose or improving the durability of the cloth without increasing its weightO
The fabric made in accordance with the present inventic~
provides an irnproved appearance over prior treated wire cloth screening without the irregularities or bare spots which are norrnally present in prior treated wire screens.
The present invention eliminates the necessity for providing a woven selvage in the wire screen while avoiding the danger of raveling during subsequent handling and thereby enabling substantial economies in the manufacture and use of the wire screen material.
The plastic-wire cloth screen of the present invention is an improvement over the plastic screening in that the screen-ing of the present invention is resistant to damage from -3a-t828 concentrated heat or inadvertent impact, does not bag or sag, or melt, and cannot be gnawed by rodents or other animal lifeO
The present invention enables the use of a film of plastic which is sufficiently thin to avoid obstructing the interstices of the woven wire, thereby avoiding impairment of visibility through the wire and airflow through the wire. On the other hand, the screen may be made in accordance with the present invention so as to increase the thickness of the film of plastic to fill up the interstices of the woven wire and thereby obtain a controlled degree of permeability or percentage of open area.
All of the objects of the invention are more fully set forth hereinafter with reference to the accompanying drawings, wherein:
Figo 1 is a plan view of a plastic-wire fabric made in accordance with the present invention;
Fig. 2 is an enlarged cross-section through the fabric shown in Fig. l;
Fig. 3 is a greatly enlarged view of an intersection portion of Fig. 2 encircled at 3 illustrating the film thickness obtained on the intersection of the wires in accordance with the present invention;
Fig. 4 is a schematic view of the preferred apparatus employed for incorporating the plastic on the woven wire base fabric of the present invention; and Fig. 5 is a diagrammatic perspective view illustrating a preferred apparatus for depositing the powdered resinous material upon the woven wire.
Referring to the drawing, Figo 1 illustrates a flexible, plastic-wire cloth made in accordance with the invention for use as insect screening. In this embodiment of the invention, the llVU8Z8 wire cloth is woven on a loom with a plain weave having eighteen warp wires 11 to the inch and sixteen weft wires 12 to the inch.
In this example, the fabric is woven from 0.011 wire drawn frorn an aluminum-clad rod through a succession of dies. The spacing of the wires provides interstices 14, the size of which determines the porosity or the percentage of open area of the wire clothO
In accordance with the present invention, the wire cloth is provided with a continuous film which encapsulates the elements of the wire cloth, in the present instance, the warp wires 11 and the weft wires 12. As shown in Fig. 3, the contin-uous uninterrupted plastic film is designated by the reference character 15 and in the present instance has a thickness less than 0.1 times the thickness of the wire, for example in the range of 0.0007". A fllm of this thickness does not substantially affect the size of the interstices 14 in the woven wire, but is effective to lock the warp and weft elements together and to protect the wire elements from the corrosive elernents in the environment where the cloth is used. Where the film is of sub-stantially greater thickness, it is effective to reduce the size of the interstices 14 and will affect the percentage of open area of the fabric. As shown in Fig. 3, the wire fabric of the present invention assures intimate contact between the weft wires 12 and the warp wires 11 at each intersection~ the degree of which is controlled in conventional manner by the settings of the loom on which the wire is woven and the diameter and hardness of the wire used in fabricating the cloth~
In the present instance, the cloth of the present invention is fabricated in a two-stage process. In the first stage, the wire cloth is woven on a conventional wire loom without selvages and is collected on a cloth roll 21 in con-tinuous lengths suitable for handling in the mill. In the second 110~ 8 stage, the roll 21 of wire cloth from the loom is treated to encapsulate the elements of the cloth in a plastlc film.
As diagrammed in Fig. 4, the operations in the second stage operate to cleanse and rinse the wire fabric to remove the dirt, grease or other foreign matter from the surface of the wire elements of the cloth. Preferably, the cleansing is accomplished by unwinding the fabric from the roll 21 through a tension device 22 into a cleansing bath 23~ After several passes through an alkaline solution in the bath 23, the cloth is subjected to a spray rinse in the rinse section 24.
From the rinse section 24, the wire cloth is passed over a chill roll 31 in two runs 25 and 26 in a drying oven 30 and into a powder-coating structure 270 In this structure, the cleansed wire cloth is passed through an electrostatically-charged cloud of a particulate powdered resin which deposits a layer of powdered particulate material on the wire cloth passing therethrough.
In the present instance, the powder-coated wire cloth is then passed through the oven 30 in runs 28 and 29 which parallel the drying runs 25 and 260 The heat of the oven fuses and flows the powder into a continuous unbroken integral film which encapsulates the wire elements of the cloth, the composite plastic-wire cloth reversing direction at the top of the oven through the use of a suitably cooled chill roll 32 which permits reversal of the travel of the plastic-wire material without stripping the plastic film or otherwise destroying its integrityO
Completion of the passage of the plastic-wire cloth through the oven completes the cure of the plastic film and the plastic-wire cloth is drawn by a variable speed drive 33 onto the takeup roll 34.
The powdered resinous particula~e material is fed to the powder-depositing apparatus 27 from a suitable supply chamber 35 which feeds from the bottom through a suitable metered and controlled feed device indicated diagrammatically at 36 and excess material is withdrawn from the apparatus and returned to the feed chamber, as indicated schematically at 37 ~ sO as to mix with the fresh material supplied directly to the chamber.
Fluidizing air is also introduced into the apparatus and is dis-charged with the excess powdered resinous material.
In operation, the rolls of cloth from the looms are fed sequentially through the apparatus with the leading end of each roll being attached to the trailing end of the preceding roll so that the fabricating line may be operated continuously at an economical rate of speed as determined by the cleaning and rinsing operation and the depositing apparatus. The height of the oven is designed to insure complete drying of the wire cloth entering the depositing apparatus and complete curing of the plastic film leaving the oven.
A preferred embodiment of the powder-depositing apparatus is shown in Fig. 5 wherein the cleansed wire cloth is introduced from the drying run 26 under a suitable feed roller 41 and upwardly between a pair of baffle plates 42 and 43~ The cloth passes outwardly at the upper end of the plates into a shroud 44 having an exit slot 45 at its upper extremity through which the cloth with powder deposited thereon is advanced into the first heating run 2~o A cloud of ionized resinous powder is formed within the shroud 44 on opposite sides of the cloth path above the upper edges of the baffle plates 42 and 43~ To this end, dry fluidizing air is introduced into manifolds 52 and 53 on opposite sides of the baffle plates 42 and 43~ respectively, as indicated by the arrows 51~ At their upper side, the chambers 52 and 53 corqmunicate with ionizing chambers 54 and 55 ~7~
110~8~8 respectively, having high voltage electrodes therein for ionizing the air passing upwardly from the manifolds 52 and 53.
Resinous powdered material is introduced above the ionizing chambers 54 and 55, for example in powder chambers 56 and 57, and the powdered material introduced therein is ionized by the charged air flowing upwardly therethrough.
The upward flow of air in the charging chambers 56 and 57 generates a floating cloud of powdered resinous material within the shroud 44 on opposite sides of the cloth path, The air is withdrawn from the chamber between the baffle plates 42 and 43 and is discharged between the baffle plates and through the bottom countercurrent to the direction of travel of the cloth, as indicated by the arrows at 61. The ionized powder is deposited on the grounded ~ire cloth passing upwardly between the baffles and the thickness of the powder layer deposited on the cloth is accurately controlled by controlling the ionizing voltage applied to the devices 54 and 55 and by line speed of the wire cloth in relation to the airflow introduced at 51. The discharged-air flow 61 is slightly greater than the flow of air introduced at 51 so that there is a net inflow of air through the discharge slot 45O
In its passage between the baffle plates 42 and 43 and through the shroud 44, the ~ire cloth receives a thorough deposit of thepowdered material from the charged powdered cloud within the shroudO The powder is fluidized by the airflow through the charging chamber so that a uniform deposition of the powder on the screen is obtained in accordance with the line speed of the wire cloth, the charging characteristics of the powder and the voltage applied to the ionizing devicesD As the powder particles become charged, they repel each other to such a degree that they rise above the fluidizing chamber and form a cloud of powdered l~O(~Z8 resinous material. The presence of a cloud of powdered resinous material on opposite sides of the cloth path at the exit end of the baffle plates 42 and 43 within the shroud 44 insures uniform depositing of the powder on opposite sides of the cloth. The charged powder is attracted to the wire cloth and the powder insulates the grounded wire cloth as it is deposited thereon~
In the event bare spots free of powder are left on the wire, the ionized powder is attracted to the bare spots and thus, the apparatus automatically tends to close any gaps which might be present in the deposited powder, and an uninterrupted coating of powder is obtained. As the cloth is thereafter passed through the oven in its upward run 2~, the deposited powder is heat-flowed to form a continuous unbroken film which encapsulates the wire elements. The nature of the film formed on the wire cloth insures continuous encapsulation of the elerlents regardless of the presence or absence of an actual adherence of the plastic film to the wire elementsO Thus, the plastic rnaterial employed to encapsulate the elements may be selected without regard to its bonding characteristics relative to the wire forrning the body of the plastic-wire clothO The plastic material of the preferred embodiment is readily available in powdered particulate form, but other film-forming particulate substances may be used which comprise a suspension of particles in a suitable carrier which is driven off when the material is formed into a continuous filmO
The plastic-wire cloth produced in accordance with the present invention provides a flexible fabric having a strength determined primarily by the strength of the wire elements in the body of the fabric. The cloth of the present invention has been fabricated from both alurninum and steel wire in various wire sizes and meshO The wire elernents are provided ~ith a continuous _9_ ~OU8~8 film of substantially uniforrn thickness ~hroughout, including the intersections where the warp and weft wire elements cross over one another in direct contact, as shown in Fig. 3O The continuous film encapsulating the woven wire enables the wire to be woven without providing the conventional selvages which are deemed necessary in untreated wire to avoid raveling. The freedom from raveling provided by the plastic-wire fabric of the present invention also enables the use of the wire in situations requiring irregular shapes or sizes of clothO The plastic film may be inert and may include fillers, pigments, or other additives to produce a wide variety of characteristics in the plastic-wire clothO The resin used in the commercial insect screening embodying the present invention has been a thermo-setting, thin-filrll, epoxy resin which is electrically non-conductive, having a smooth velvet-like finish and a dark color such as gun-metal gray or black to provide good visibility through the screening. The plastic resin may be formulated to provide any desired degree of modification of the flexibility or rigidity of the cloth, and as noted above, the thickness of the film may be increased to reduce the permea~ility or percentage of open area of the screen by partially closing or completely closing the interstices in the woven wireO
While particular embodiments of the present invention have been illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.
The improved screening of the present invention is fabricated by weaving a flexible wire fabric and applying a plastic film to the components of the fabric after weaving by coating the woven components with a powdered resin and curing the resin in place on the woven screening to generate an un-interrupted plastic film on the components.
In particular, the powdered resinous material is deposited on the woven wire by electrostatic deposition which is readily controlled so as to effectively deposit an uninter-rupted coating upon the component which, when cured, forms an integral film thereon.
Thus the present invention provides a method of making a plastic-wire cloth comprising the steps of weaving a continuous length of fabric of wire elements of electrically conductive material, passing said woven~wire fabric first through an alkaline bath to remove the dirt, grease or other foreign matter from the surface of the wire elements, second through a spray rinse to complete the cleansing, third through a drying oven to dry the woven-wire fabric, and fourth from said oven through a cloud of charged particles of a film-forming powdered resinous material at a rate of feed to deposit a continuous layer of particles on the wire elements of said fabric in a thickness suitable for forming a continuous film, and then heating said continuous length of woven-wire fabric to heat-flow said particulate material into a continuous unbroken integral film which is cured and encap-sulates the individual wire elements of said fabric.
. .
...
-:
~' ~ ' ..
The present invention provides a plastic-wire cloth which is flexible and rnay readily bend without fracturing the film or causing the filr~ to flake. The encapsulated components provide a substantially improved strength-to-weight ratio enabling either the use of a lighter cloth for a comparable purpose or improving the durability of the cloth without increasing its weightO
The fabric made in accordance with the present inventic~
provides an irnproved appearance over prior treated wire cloth screening without the irregularities or bare spots which are norrnally present in prior treated wire screens.
The present invention eliminates the necessity for providing a woven selvage in the wire screen while avoiding the danger of raveling during subsequent handling and thereby enabling substantial economies in the manufacture and use of the wire screen material.
The plastic-wire cloth screen of the present invention is an improvement over the plastic screening in that the screen-ing of the present invention is resistant to damage from -3a-t828 concentrated heat or inadvertent impact, does not bag or sag, or melt, and cannot be gnawed by rodents or other animal lifeO
The present invention enables the use of a film of plastic which is sufficiently thin to avoid obstructing the interstices of the woven wire, thereby avoiding impairment of visibility through the wire and airflow through the wire. On the other hand, the screen may be made in accordance with the present invention so as to increase the thickness of the film of plastic to fill up the interstices of the woven wire and thereby obtain a controlled degree of permeability or percentage of open area.
All of the objects of the invention are more fully set forth hereinafter with reference to the accompanying drawings, wherein:
Figo 1 is a plan view of a plastic-wire fabric made in accordance with the present invention;
Fig. 2 is an enlarged cross-section through the fabric shown in Fig. l;
Fig. 3 is a greatly enlarged view of an intersection portion of Fig. 2 encircled at 3 illustrating the film thickness obtained on the intersection of the wires in accordance with the present invention;
Fig. 4 is a schematic view of the preferred apparatus employed for incorporating the plastic on the woven wire base fabric of the present invention; and Fig. 5 is a diagrammatic perspective view illustrating a preferred apparatus for depositing the powdered resinous material upon the woven wire.
Referring to the drawing, Figo 1 illustrates a flexible, plastic-wire cloth made in accordance with the invention for use as insect screening. In this embodiment of the invention, the llVU8Z8 wire cloth is woven on a loom with a plain weave having eighteen warp wires 11 to the inch and sixteen weft wires 12 to the inch.
In this example, the fabric is woven from 0.011 wire drawn frorn an aluminum-clad rod through a succession of dies. The spacing of the wires provides interstices 14, the size of which determines the porosity or the percentage of open area of the wire clothO
In accordance with the present invention, the wire cloth is provided with a continuous film which encapsulates the elements of the wire cloth, in the present instance, the warp wires 11 and the weft wires 12. As shown in Fig. 3, the contin-uous uninterrupted plastic film is designated by the reference character 15 and in the present instance has a thickness less than 0.1 times the thickness of the wire, for example in the range of 0.0007". A fllm of this thickness does not substantially affect the size of the interstices 14 in the woven wire, but is effective to lock the warp and weft elements together and to protect the wire elements from the corrosive elernents in the environment where the cloth is used. Where the film is of sub-stantially greater thickness, it is effective to reduce the size of the interstices 14 and will affect the percentage of open area of the fabric. As shown in Fig. 3, the wire fabric of the present invention assures intimate contact between the weft wires 12 and the warp wires 11 at each intersection~ the degree of which is controlled in conventional manner by the settings of the loom on which the wire is woven and the diameter and hardness of the wire used in fabricating the cloth~
In the present instance, the cloth of the present invention is fabricated in a two-stage process. In the first stage, the wire cloth is woven on a conventional wire loom without selvages and is collected on a cloth roll 21 in con-tinuous lengths suitable for handling in the mill. In the second 110~ 8 stage, the roll 21 of wire cloth from the loom is treated to encapsulate the elements of the cloth in a plastlc film.
As diagrammed in Fig. 4, the operations in the second stage operate to cleanse and rinse the wire fabric to remove the dirt, grease or other foreign matter from the surface of the wire elements of the cloth. Preferably, the cleansing is accomplished by unwinding the fabric from the roll 21 through a tension device 22 into a cleansing bath 23~ After several passes through an alkaline solution in the bath 23, the cloth is subjected to a spray rinse in the rinse section 24.
From the rinse section 24, the wire cloth is passed over a chill roll 31 in two runs 25 and 26 in a drying oven 30 and into a powder-coating structure 270 In this structure, the cleansed wire cloth is passed through an electrostatically-charged cloud of a particulate powdered resin which deposits a layer of powdered particulate material on the wire cloth passing therethrough.
In the present instance, the powder-coated wire cloth is then passed through the oven 30 in runs 28 and 29 which parallel the drying runs 25 and 260 The heat of the oven fuses and flows the powder into a continuous unbroken integral film which encapsulates the wire elements of the cloth, the composite plastic-wire cloth reversing direction at the top of the oven through the use of a suitably cooled chill roll 32 which permits reversal of the travel of the plastic-wire material without stripping the plastic film or otherwise destroying its integrityO
Completion of the passage of the plastic-wire cloth through the oven completes the cure of the plastic film and the plastic-wire cloth is drawn by a variable speed drive 33 onto the takeup roll 34.
The powdered resinous particula~e material is fed to the powder-depositing apparatus 27 from a suitable supply chamber 35 which feeds from the bottom through a suitable metered and controlled feed device indicated diagrammatically at 36 and excess material is withdrawn from the apparatus and returned to the feed chamber, as indicated schematically at 37 ~ sO as to mix with the fresh material supplied directly to the chamber.
Fluidizing air is also introduced into the apparatus and is dis-charged with the excess powdered resinous material.
In operation, the rolls of cloth from the looms are fed sequentially through the apparatus with the leading end of each roll being attached to the trailing end of the preceding roll so that the fabricating line may be operated continuously at an economical rate of speed as determined by the cleaning and rinsing operation and the depositing apparatus. The height of the oven is designed to insure complete drying of the wire cloth entering the depositing apparatus and complete curing of the plastic film leaving the oven.
A preferred embodiment of the powder-depositing apparatus is shown in Fig. 5 wherein the cleansed wire cloth is introduced from the drying run 26 under a suitable feed roller 41 and upwardly between a pair of baffle plates 42 and 43~ The cloth passes outwardly at the upper end of the plates into a shroud 44 having an exit slot 45 at its upper extremity through which the cloth with powder deposited thereon is advanced into the first heating run 2~o A cloud of ionized resinous powder is formed within the shroud 44 on opposite sides of the cloth path above the upper edges of the baffle plates 42 and 43~ To this end, dry fluidizing air is introduced into manifolds 52 and 53 on opposite sides of the baffle plates 42 and 43~ respectively, as indicated by the arrows 51~ At their upper side, the chambers 52 and 53 corqmunicate with ionizing chambers 54 and 55 ~7~
110~8~8 respectively, having high voltage electrodes therein for ionizing the air passing upwardly from the manifolds 52 and 53.
Resinous powdered material is introduced above the ionizing chambers 54 and 55, for example in powder chambers 56 and 57, and the powdered material introduced therein is ionized by the charged air flowing upwardly therethrough.
The upward flow of air in the charging chambers 56 and 57 generates a floating cloud of powdered resinous material within the shroud 44 on opposite sides of the cloth path, The air is withdrawn from the chamber between the baffle plates 42 and 43 and is discharged between the baffle plates and through the bottom countercurrent to the direction of travel of the cloth, as indicated by the arrows at 61. The ionized powder is deposited on the grounded ~ire cloth passing upwardly between the baffles and the thickness of the powder layer deposited on the cloth is accurately controlled by controlling the ionizing voltage applied to the devices 54 and 55 and by line speed of the wire cloth in relation to the airflow introduced at 51. The discharged-air flow 61 is slightly greater than the flow of air introduced at 51 so that there is a net inflow of air through the discharge slot 45O
In its passage between the baffle plates 42 and 43 and through the shroud 44, the ~ire cloth receives a thorough deposit of thepowdered material from the charged powdered cloud within the shroudO The powder is fluidized by the airflow through the charging chamber so that a uniform deposition of the powder on the screen is obtained in accordance with the line speed of the wire cloth, the charging characteristics of the powder and the voltage applied to the ionizing devicesD As the powder particles become charged, they repel each other to such a degree that they rise above the fluidizing chamber and form a cloud of powdered l~O(~Z8 resinous material. The presence of a cloud of powdered resinous material on opposite sides of the cloth path at the exit end of the baffle plates 42 and 43 within the shroud 44 insures uniform depositing of the powder on opposite sides of the cloth. The charged powder is attracted to the wire cloth and the powder insulates the grounded wire cloth as it is deposited thereon~
In the event bare spots free of powder are left on the wire, the ionized powder is attracted to the bare spots and thus, the apparatus automatically tends to close any gaps which might be present in the deposited powder, and an uninterrupted coating of powder is obtained. As the cloth is thereafter passed through the oven in its upward run 2~, the deposited powder is heat-flowed to form a continuous unbroken film which encapsulates the wire elements. The nature of the film formed on the wire cloth insures continuous encapsulation of the elerlents regardless of the presence or absence of an actual adherence of the plastic film to the wire elementsO Thus, the plastic rnaterial employed to encapsulate the elements may be selected without regard to its bonding characteristics relative to the wire forrning the body of the plastic-wire clothO The plastic material of the preferred embodiment is readily available in powdered particulate form, but other film-forming particulate substances may be used which comprise a suspension of particles in a suitable carrier which is driven off when the material is formed into a continuous filmO
The plastic-wire cloth produced in accordance with the present invention provides a flexible fabric having a strength determined primarily by the strength of the wire elements in the body of the fabric. The cloth of the present invention has been fabricated from both alurninum and steel wire in various wire sizes and meshO The wire elernents are provided ~ith a continuous _9_ ~OU8~8 film of substantially uniforrn thickness ~hroughout, including the intersections where the warp and weft wire elements cross over one another in direct contact, as shown in Fig. 3O The continuous film encapsulating the woven wire enables the wire to be woven without providing the conventional selvages which are deemed necessary in untreated wire to avoid raveling. The freedom from raveling provided by the plastic-wire fabric of the present invention also enables the use of the wire in situations requiring irregular shapes or sizes of clothO The plastic film may be inert and may include fillers, pigments, or other additives to produce a wide variety of characteristics in the plastic-wire clothO The resin used in the commercial insect screening embodying the present invention has been a thermo-setting, thin-filrll, epoxy resin which is electrically non-conductive, having a smooth velvet-like finish and a dark color such as gun-metal gray or black to provide good visibility through the screening. The plastic resin may be formulated to provide any desired degree of modification of the flexibility or rigidity of the cloth, and as noted above, the thickness of the film may be increased to reduce the permea~ility or percentage of open area of the screen by partially closing or completely closing the interstices in the woven wireO
While particular embodiments of the present invention have been illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.
Claims (3)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of making a plastic-wire cloth comprising the steps of weaving a continuous length of fabric of wire elements of electrically conductive material, passing said woven-wire fabric first through an alkaline bath to remove the dirt, grease or other foreign matter from the surface of the wire elements, second through a spray rinse to complete the cleansing, third through a drying oven to dry the woven-wire fabric, and fourth from said oven through a cloud of charged particles of a film-forming powdered resinous material at a rate of feed to deposit a continuous layer of particles on the wire elements of said fabric in a thickness suitable for forming a continuous film, and then heating said continuous length of woven-wire fabric to heat-flow said particulate material into a continuous unbroken integral film which is cured and encapsulates the individual wire elements of said fabric.
2. A method according to claim 1 wherein said cleansed and dried fabric is passed lengthwise between a pair of baffle plates, said cloud of charged particles being disposed on opposite sides of said fabric of the exit end of said baffle plates, said clouds being suspended in a flow of fluidizing air, said air being discharged between said baffle plates countercurrent to the direction of travel of said fabric.
3. A method according to claim 2 wherein said fabric is caused to travel upwardly through the cloud in a vertical run and continues in its vertical travel into said drying oven to cure the particulate material into said continuous film.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US71842576A | 1976-08-27 | 1976-08-27 | |
| US718,425 | 1976-08-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1100828A true CA1100828A (en) | 1981-05-12 |
Family
ID=24886051
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,943A Expired CA1100828A (en) | 1976-08-27 | 1977-08-03 | Plastic-wire cloth and method of making the same |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1100828A (en) |
-
1977
- 1977-08-03 CA CA283,943A patent/CA1100828A/en not_active Expired
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