Abstract: An electrode material containing active material powder is prepared. Dry classification of the electrode material is performed by a classifier. An electrode is manufactured by using the electrode material subjected to the dry classification. The classifier includes a mesh screen, a blade, and a motor. Breakage of the mesh screen is detected by monitoring either or both of an operation sound of the classifier and torque of the motor. The electrode material contained in the classifier will no longer be used for manufacturing of the electrode when breakage of the mesh screen is detected.

Abstract: A modular, pre-tensioned, self-cleaning screening panel having a frame and at least one pre-tensioned wire that is fastened to the frame.

Abstract: A shale shaker buffer and wear reduction barrier, placed between a shale shaker filter screen, shale shaker wear items and a shale shaker deck of a shale shaker for the prevention of vibratory and friction-induced wear that is reversibly adhered, placeable and replaceable to a shale shaker filter screen, shale shaker wear items and a shale shaker deck of a shale shaker basket to decrease wear on a shale shaker's functional components, singularly and in combination. The buffer and wear reduction barrier that is the present invention serves the additional function of a solids control barrier as an operable seal between a shale shaker filter screen, wear items and deck of a shale shaker to obviate entrance of solids into mud pits via wear induced areas of separation between shale shaker filter screen, wear items and a deck of a shale shaker.

Abstract: A screen panel has a pre-tensioned screen with a polished metal plate mounted to the top of the frame to eliminate all the exposed surface areas of epoxy which secures the screen to the screen panel frame. The metal plate also provides an edge against which a silicone bead may be seated to provide a much cleaner and finished looking panel which is anticipated to meet the standards set forth by the USDA. Additionally, the spatial positioning of the plate atop the screen material and screen frame allows for a clean and smooth transition across the components and one which may accept a finished bead of silicon or other material for reducing and/or eliminating sites for mold growth or other containments thereby enhancing the ability to clean and sterilize the screen panel for the processing of various materials.

Abstract: A shale shaker for separating solids from solids laden drilling fluid is disclosed as having a basket with a scalping screen deck, at least one first screen deck and at least one second screen deck. The basket further may have a flow tray arranged between said scalping screen deck and at least one first screen deck, and a plurality of first ducts and a plurality of second ducts, the plurality of first ducts for directing solids laden drilling fluid to the at least one first screen deck. The second plurality of second ducts are for directing solids laden drilling fluid to said second screen deck.

Abstract: Generally, the present disclosure is related to systems and methods for separating hydrocarbons and/or other liquids from drill cuttings material. One illustrative embodiment disclosed herein is directed to a system that includes, among other things, a thermal reactor that is adapted to remove liquid from drill cuttings material by heating the drill cuttings material to at least a first temperature that is sufficiently high enough to vaporize the liquid. The illustrative system also includes a feeder system that is adapted to controllably feed a flow of the drill cuttings material to the thermal reactor, and a control system that is adapted to control the flow of the drill cuttings material from the feeder system so as to maintain a temperature in the thermal reactor at or above the first temperature.

Abstract: There is provided a plug for repairing a sifting or filtering screen, the plug comprising a body (1) of a first material supporting an area of a second material which is more resilient than the first material, in use the area of a second material serving as a seal (2) to engage and seal against the screen in order to plug a cell aligned with a damaged area of the screen. A second plug has a body (101) formed with holes (108) to receive securing members such as screws, the holes being positioned to enable the securing members (109) to pass into the material of the sifting or filtering screen in order releasably to secure the plug in a cell aligned with a damaged area of the sifting screen.

Abstract: A screen panel with improved apertures for mining and quarrying industries adapted to be mounted on a screen deck, including a screening surface made up of materials such as herein described formed on a reinforcing frame, said screen panel having suitably designed apertures for allowing materials to pass through, said apertures having resilient ribs (5) with protrusions (4) on both sides configured with respect to each other such that adequate open space exists, whereby clogging of materials pursuant to screening operations are substantially reduced.

Abstract: A woven wire screening for use in classifying material flowing therethrough and a method of forming the same. The woven wire screening includes a plurality of warp wires and a plurality of weft wires. The plurality of warp wires and the plurality of weft wires are interwoven to form an integral wire cloth having a plurality of openings for permitting material to be classified to flow through the openings. The integral wire cloth includes an upper screening surface configured to enhance the tumbling action of product impacting the upper screening surface to improve throughput of the woven wire screening.

Abstract: A screening having a plurality of warp elements. The plurality of warp elements includes first and second warp elements each having a plurality of undulations oriented in any desired manner including but not limited to horizontal or vertical. At least one retaining member is operably associated with the plurality of warp elements to form an integral screen segment having a plurality of openings. The first warp element has at least one characteristic different from the second warp element to prevent blinding of the screen segment. The at least one characteristic affecting movement of the first warp element and the second warp element when the screen segment is used to classify material such that at least one of amplitude and frequency of movement of the first warp screening element is different from that of the second warp element when subjected to the same operating condition.

Abstract: An impact screen cloth for use in a screening device for screening out oversize objects in a material flowing in a direction is provided, comprising a metal plate having a perimeter and comprising a plurality of openings therethrough and forming a grid having longitudinal ligaments substantially parallel to the direction of the material flow and transverse ligaments substantially perpendicular to the direction of the material flow; and a number of longitudinal wear bars positioned on an equal number of longitudinal ligaments to cover a substantial portion of the number of longitudinal ligaments without substantially interfering with the openings.

Abstract: The present disclosure is generally directed to vibratory separators that are used for processing drilling fluid, and in particular, vibratory separators that utilize electro-magnetic clamping apparatuses for attaching screen assemblies to a basket assembly. In one exemplary embodiment, an illustrative vibratory separator is disclosed which includes, among other things, a basket assembly having at least one screen support, and at least one screen assembly that is adapted to be releasably secured to the at least one screen support. Additionally, the disclosed vibratory separator also includes an electro-magnetic clamp apparatus that is adapted to releasably secure the at least one screen assembly to the at least one screen support when the electro-magnetic clamp apparatus is energized to a magnetized state, and to release the at least one screen assembly from the at least one screen support when the electro-magnetic clamp apparatus is de-energized to an un-magnetized state.

Abstract: A shaker screen for attachment to a bed of a shaker includes a screen frame having at least one mesh screen attached to the top side of the screen frame, wherein the screen frame is preferentially bowed prior to attaching the mesh screen to the screen frame.

Abstract: The invention relates to a screen for a screening machine for screening a product into two fractions. To avoid detrimental effects to the quality of the product due to damage at the screen mesh of a screen (9), the screen is provided with a metal layer, in particular in the manner of a conduction path, wherein the electrical resistance of said layer is measured and wherein changes in the resistance indicate damages.

Abstract: A method of making a screen with an apparatus, the screen including a plurality of wires arranged in a patterned configuration, the apparatus including an extruder and a mold, the method including (a) longitudinally aligning the plurality of wires in the apparatus in a first direction only and arranging the wires in the patterned configuration, (b) applying a first bead of molten material on the wires via the extruder, and (c) directly molding the first bead of molten material into a support member for the screen by closing the mold about the bead, wherein the support member at least partially encases at least one of the wires.

Abstract: A sifting implement for use with a container, such as a wheelbarrow or bucket. The sifting implement includes a frame having an opening through which compost, dirt, rocks, sand, or other material is sifted. A primary screen is supported in the opening to catch larger items in the material being sifted. Other screens are used for separating different size materials. A bracket is attached to the implement and engages an edge of the container, which allows the implement to be tilted in order to dump the larger items. The sifting implement also includes a containment border disposed around the opening to direct the separated items toward the front of the implement when the implement is tilted to dump the items.

Abstract: A screen assembly for separating solid materials of differing sizes in a material stream, having a support, and a screen arrangement placed upon the support, wherein the support has at least one seal placed on the support, the seal configured to interface with a mounting surface of a shaking apparatus.

Abstract: A supporting structure for different screening media on a vibrating screen is disclosed, as well as a support carrier of the supporting structure. The supporting structure is received on a vibrating screen and has a number of support carriers arranged parallel to each other and perpendicular to a number of transversal carriers. The support carriers and the transversal carriers form a grid. The support carriers have grooves at each end to be snapped on and locked on circular ribs on top of the transversal carriers. The support carriers are made of a polymeric material and are elongated elements.

Abstract: A screen panel for use in a vibrating screen device. The screen panel has a plurality of in-flow slots and cross-flow slots arranged in a regular pattern to provide enhanced open area for a given slot size.

Abstract: A screening panel is provided for screening particulate materials. The screening panel includes a peripheral frame and a plurality of ribs. The peripheral frame has an upper surface, a lower surface, and an outer peripheral surface interconnecting the upper surface and lower surface. Further, the peripheral frame defines an opening. The ribs extend across the opening and define a screening surface. Each of the plurality of ribs has a substantially flat upper surface. The screening panel further includes at least one generally arcuate raised member extending from the upper surface of each of the plurality of ribs. The raised members facilitate screening the particulate materials.

Abstract: A screening panel is provided for screening particulate materials. The screening panel includes a peripheral frame and a plurality of ribs. The peripheral frame has an upper surface, a lower surface, and an outer peripheral surface interconnecting the upper surface and lower surface. Further, the peripheral frame defines an opening. The ribs extend across the opening and define a screening surface. Each of the plurality of ribs has a substantially flat upper surface. The screening panel further includes at least one generally arcuate raised member extending from the upper surface of each of the plurality of ribs. The raised members facilitate screening the particulate materials.

Abstract: A mesh panel of the type having a plurality of spaced apart apertures includes an internal frame member substantially in the form of a perforated sheet, and having a plurality of openings therein larger than the apertures. The frame member has substantial internal rigidity. An elastomeric coating encapsulates at least a portion of said frame member. In a preferred embodiment, a bonding coating between the elastomeric coating and the frame member securely bonds to both the elastomeric coating and the frame member. The bonding coating is of the type that is liquid before application to the frame member and is curable by heat or time to a hard plastic. Preferably, the bonding coating is partially cured before the elastomeric coating is applied, after which both coatings are cured by heat. The panel is particularly well suited for use as a sorting screen.

Abstract: The invention relates to a screen for a screening machine for screening a product into two fractions. To avoid detrimental effects to the quality of the product due to damage at the screen mesh of a screen (9), the screen is provided with a metal layer, in particular in the manner of a conduction path, wherein the electrical resistance of said layer is measured and wherein changes in the resistance indicate damages.

Abstract: A method of making a screen with an apparatus, the screen including a plurality of wires arranged in a patterned configuration, the apparatus including an extruder and a mold, the method including (a) longitudinally aligning the plurality of wires in the apparatus in a first direction only and arranging the wires in the patterned configuration, (b) applying a first bead of molten material on the wires via the extruder, and (c) directly molding the first bead of molten material into a support member for the screen by closing the mold about the bead, wherein the support member at least partially encases at least one of the wires.

Abstract: A screen for a vibratory separator, the screen including at least two layers of screening material, including a first layer and a second layer, the first layer made of a plurality of intersecting first wires, the second layer made of a plurality of intersecting second wires, the first wires including first shute wires and first warp wires, the second wires including second shute wires and second warp wires, certain of the first warp wires aligned with a second warp wire, and/or certain of the first shute wires aligned with a second shute wire. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 CFR 1.72(b).

Abstract: A woven wire screening for use in classifying material flowing therethrough and a method of forming the same. The woven wire screening includes a plurality of warp wires and a plurality of weft wires. The plurality of warp wires and the plurality of weft wires are interwoven to form an integral wire cloth having a plurality of openings for permitting material to be classified to flow through the openings. The plurality of warp wires are crimped to form upper and lower knuckles. The plurality of weft wires are crimped to form upper and lower knuckles. Preferably, the plurality of weft wires are crimped deeper than the plurality of warp wires such that the upper knuckles of the weft wires are higher than the upper knuckles of the warp wires creating a knuckle height differential between the upper knuckles of the weft wires and the upper knuckles of the warp wires.

Abstract: A frame over which woven wire mesh is to be stretched and secured to form a sieving screen and which can be used to screen solids from drilling mud recovered from down-hole when drilling for oil or gas. The frame comprises a rectilinear molded plastics frame having edge regions by which it is secured in place in a shaker. Within the frame is a plurality of rectilinear windows formed by an orthogonal array of intersecting ribs also of molded plastics material. Some of the ribs are internally reinforced by a structure comprising two spaced apart layers of orthogonal intersecting spaced apart wires, running parallel to the length and breadth of the rectilinear shape of the frame within the ribs to increase their rigidity. The edge regions of the frame are reinforced internally by metal box-section members joined at their four corners and defining perimeter reinforcement, and the ends of the wires are secured to the box-section members.

Abstract: A vibrating sieve for classifying a particulate material, including an oscillator comprising a transducer; and at least two meshes layered together and located in contacting relation to a transducer, wherein a lowermost mesh receiving a vibration from the transducer transmits the vibration to an uppermost mesh to classify the particulate material fed thereon.

Abstract: A screen includes three or four layers of woven metal screen cloth. The coarsest of these layers is a structural layer includes threads which are woven into the cloth with surfaces which are fusible below a temperature at which the other layers of screen cloth are heat affected. These woven threads include each of the threads in the coarse screen cloth with the coated threads being wire with fusible polypropylene or polyethylene coatings. The cloth could alternatively be coated or a fusible grid used between screens instead. A support layer above the structural layer may include a woven metal screen with woven elements which are either coated with fusible material or are solidly of fusible material woven periodically therethrough in at least one direction. A fusible grid could alternatively be employed. Screens are laminated with one or two fine mesh screens heated on the support woven screen cloth with fusible surfaces to locate the fusible material in the finer cloths.

Abstract: A woven wire screening for use in classifying material flowing therethrough and a method of forming the same. The woven wire screening includes a plurality of warp wires and a plurality of weft wires. The plurality of warp wires and the plurality of weft wires are interwoven to form an integral wire cloth having a plurality of openings for permitting material to be classified to flow through the openings. The plurality of warp wires are crimped to form upper and lower knuckles. The plurality of weft wires are crimped to form upper and lower knuckles. Preferably, the plurality of weft wires are crimped deeper than the plurality of warp wires such that the upper knuckles of the weft wires are higher than the upper knuckles of the warp wires creating a knuckle height differential between the upper knuckles of the weft wires and the upper knuckles of the warp wires.

Abstract: Screen assemblies for vibratory separators and shale shakers, the screen assemblies in certain aspects having screening material with a protector on an outer periphery of the screening material; and methods of making such screen assemblies. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 C.F.R. 1.72(b).

Abstract: A screen for a vibratory separator, the screen including at least two layers of screening material, including a first layer and a second layer, the first layer made of a plurality of intersecting first wires, the second layer made of a plurality of intersecting second wires, the first wires including first shute wires and first warp wires, the second wires including second shute wires and second warp wires, certain of the first warp wires aligned with a second warp wire, and/or certain of the first shute wires aligned with a second shute wire. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 CFR 1.72(b).

Abstract: A screen for a vibratory separator, the screen including at least two layers of screening material, at least part of the at least one layer of screening material coated with a coating containing nickel or chromium, the at least two layers of screening material including a first layer and a second layer, the first layer made of a plurality of intersecting first wires, the second layer made of a plurality of intersecting second wires, the first wires including first shute wires and first warp wires, each of the first shute wires at a right angle to first warp wires, each of the first warp wires at a right angle to first shute wires, the second wires including second shute wires and second warp wires, each of the second shute wires at a right angle to second warp wires, each of the second warp wires at a right angle to second shute wires, each of the first warp wires aligned with a second warp wires, and each of the first shute wires aligned with a second shute wire.

Abstract: A vibratory plate screen having a first end for quickly mounting in a vibrator housing, an intermediate region with openings therein and a securement end that allows one to quickly secure a vibratory plate screen in a vibratory housing. In addition, the screen is sufficiently flexible to enable one to mount the vibrator screen in a curved condition or stressed condition so that the inherent tensile strength of the material assists in holding the vibratory plate screen in position. A further feature of the invention is the quick removal and securement of the vibratory plate screen.

Abstract: A screen for a vibratory separator includes holding members and a woven wire cloth. The woven wire cloth has a plurality of warp wires extending between the holding members. The warp wires define openings in the woven wire cloth for the passage of material there through. The warp wires are arranged in pairs consisting of a first warp wire and a second warp wire. The warp wires are fixed to the holding members such that the first warp wire in each of the pairs has a greater tension applied thereto than the second warp wire in each of the pairs.

Abstract: In a method of and apparatus for manufacturing a filtering screen, a frame of plastics coated metal or reinforced plastics material is located in a jig and at least two sheets of wire cloths are placed over the frame and their edges gripped by pneumatically operated clamps carried by the jig. The clamps are pneumatically driven outwardly of the frame to tension each cloth in orthogonal directions. The tensioned cloths are pressed against the frame and heated in order to bond the cloths to the frame. The heated material is allowed to cool, and after completion of the bonding step the clamps are released, allowing the frame to be removed from the jig. Where necessary the cloths are trimmed back to the edges of the frame. A separate set of pneumatically operated clamps may be provided for gripping all four edges of each wire cloth layer to allow each layer to be individually tensioned.

Abstract: A vibratory screening machine having opposite sides with a plurality of stationary aligned tensioning members mounted on one side and a plurality of nut actuated movable tensioning members mounted on the opposite side and a vibratory screening screen mounted on the stationary and movable tensioning members. The tensioning members have upstanding fingers which are received in apertures in the plates of the vibratory screen, and the edge portions of the vibratory screen include screening material which extends all of the way to the extreme edges of the supporting plate and the fingers are below the screening material. Also, the tensioning structure is mounted on the side walls of the vibratory screening machine below the vibratory screen.

Abstract: A detector for breaks in screens and filters employed in material separators includes a transmitter of RF signals and a receiver of RF signals located to either side of a screen. The separator includes a chamber having a barrier to RF signals with a path through the barrier being defined through the screen mount. The screen mount receives a screen to extend fully across the path.

Abstract: A detector for breaks in screens and filters employed in material separators includes a transmitter of RF signals and a receiver of RF signals located to either side of a screen. The separator includes a chamber having a barrier to RF signals with a path through the barrier being defined through the screen mount. The screen mount receives a screen to extend fully across the path.

Abstract: A method of plugging an area of damaged mesh in a sifting screen. The method is applicable to screens in which woven wire mesh is stretched, tensioned and secured over a supporting frame containing a plurality of windows and in which local damage to the mesh is in an area of the mesh which overlies one of the windows. The method has the steps of inserting into the window a device which is a close fit therein, and securing the device in the window so as to completely cover the area of damaged mesh. The device may be a former having stretched thereacross and secured thereto mesh similar to that stretched across the window in question, or simply a plate or block. The device may be secured in place by a force or interference fit, mechanical means, or adhesive, or the device may be resiliently deformable to allow it to be pushed past a projection in the window, so as to snap fit the device in place.

Abstract: A shale shaker or vibratory separator for treating material, e.g. in one aspect, a shale shaker for treating drilling fluid having contaminants therein, the shale shaker having a base, a basket on the base, fluid introduction apparatus for introducing the drilling fluid into the basket, screen apparatus for selectively providing screening material in or under the basket, the screening material positioned so that the drilling fluid flows onto the screening material, a primary roll of screening material, a take-up roll for receiving screening material from the primary roll, the rolls rotatably mounted so that screening material is movable, through or under the basket, and onto the take-up roll, vibratory apparatus connected to the basket for vibrating the basket, and receptacle apparatus for receiving fluid flowing through the screening material.

Abstract: A screen assembly for a vibratory separator having, in one aspect, a frame with a plurality of openings therethrough, screening material on the frame over the openings, the frame having an end area at a material exit end of the frame, and end apparatus at the end area for facilitating material movement over the end area; in one aspect, non-smooth areas on top of the screen assembly to impede solids movement on such areas and/or to direct them off such areas; vibratory separators with such a screen assembly; and methods of their use.

Abstract: A non-woven wire mesh screen having a first planar array of stainless steel wires disposed in a longitudinal direction and a second planar array of stainless steel wires disposed transverse to the first planar array. The stainless steel wires have a tensile strength greater than 200,000 psi.

Abstract: A new and unique design enhancement and use of directional and re-directional ribs on a solids control filtering screen, such as those used in drilling wells for hydrocarbons and other substances, in conjunction with a coordinated system of hanging such screens and directing and redirecting the flow of trapped solids over the surface of such screens, is disclosed for use with a shaker. The invention counteracts the natural tendency of trapped solids to migrate to and congregate in the lowest areas of a suspended screen and facilitates a dryer fluids discharge, as well as more effectively utilizing the available screening surface area, and therefore the invention reduces the incidence of screen wear and tearing and increases the flow rate conductants through the screen.

Abstract: A screening screen assembly for a vibratory screening machine including an apertured plate, and a subassembly of an undulating support screen and fine screening screen and finer screening screen bonded to each other by a fused plastic grid and bonded to the apertured plate. A method of fabricating a screening screen assembly for a vibratory screening machine including the steps of providing a support screen, superimposing a plastic grid onto the support screen, superimposing a finer screening screen onto the fine screening screen, applying heat and pressure to the superimposed screens to fuse the plastic grid and thereby form a flat bonded laminate subassembly by causing the fused plastic grid to permeate the fine screen and the finer screen and the support screen, forming the bonded laminate subassembly into an undulating shape, providing an apertured plate, and bonding the undulating bonded subassembly to the apertured plate.

Abstract: The present invention is an integrated screen comprising a screen portion having openings and an integral protector edge disposed about the periphery of the screen portion. This integrated screen protector edge can be utilized individually as the membrane support/flow field in an electrochemical cell or in conjunction with one or more subsequent screen layers. When utilized with subsequent screen layers, the integrated screen protector edge is disposed adjacent to and in intimate contact with the membrane assembly.

Abstract: A screen assembly and methods for using it, the screen assembly including, in certain aspects, at least two layers of screening material one on top of the other and including at least a first layer over a second layer, each layer having screen mesh with rectangular openings as viewed from above, the first layer having first rectangular openings, and the second layer having second rectangular openings, each of the first rectangular openings having a first width and a first length, and each of the second rectangular openings having a second width and a second length, the ratio of the first length to the first width ranging between 1.55 and 2.00, the ratio of the second length to the second width ranging between 1.55 and 2.00, the ratio of the first length to the second width ranging between 0.95 and 1.05, and the lengths of the first rectangular openings are parallel to lengths of the second rectangular openings.

Abstract: A vibratory separator for separating components of material introduced to the vibratory separator, the vibratory separator in one particular aspect being a shale shaker, the vibratory separator including a basket for holding screening apparatus, the basket having two sides spaced-apart by a first end at which the material is introduced into the basket and a second end spaced-apart from the first end, components separated from the material exiting the basket from the second end, vibrating apparatus connected to the basket for vibrating the basket, screening apparatus mounted in the basket, the screening apparatus having at least a first portion and a second portion, the first portion at the first end of the screen and the first portion lower in the basket than the second portion, receptacle apparatus below the screening apparatus for receiving material components flowing through the screening apparatus, maintenance apparatus for maintaining height of a portion of the screening apparatus, and a pool of the mate

Abstract: A new and unique design use of directional and re-directional raised ribs on a solids control filtering screen, such as those used in drilling wells for hydrocarbons and other substances, in conjunction with a coordinated system of hanging such screens and directing and redirecting the flow of trapped solids over the surface of such screens, is disclosed for use with a vibratory shaker. The invention counteracts the natural tendency of trapped solids to migrate to and congregate in the lowest areas of a suspended screen and facilitates a dryer fluids discharge, as well as more effectively utilizing the available screening surface area, and therefore the invention reduces the incidence of screen wear and tearing and increases the flow rate conductants and drying capabilities through the screen.

Abstract: A support for a screen assembly for a vibratory separator, a screen assembly with such a support, a vibratory separator with one or more such screen assemblies, and a method of using such a screen assembly, such a support having a body, a first series of holes through the body each hole having a first opening size as viewed from above, a second series of holes through the body each hole with a second opening size as viewed from above, the second series of holes at a selected area of the body and the support positionable in a vibratory separator so that the selected area is adjacent a selected location with respect to the vibratory separator, and the second opening size smaller than the first opening size and/or the second series of holes with holes spaced apart differently than the holes of the first series of holes; and in one aspect, a plastic grid with such hole series for fusing together layers of screening material.