Abstract: A method for selectively removing leukocytes from a suspension which also contains platelets, such as a platelet concentrate or whole blood. The method includes passing the suspension through a filter which includes a polysaccharide-type coating. The coating may include one or more of hydroxypropylmethyl cellulose, hydroxybutylmethyl cellulose, dextran and hydroxyethyl starch. Also provided is a filter for selectively removing leukocytes from a suspension which also contains platelets. The filter includes a substrate which is coated with a polysaccharide-type composition.

Abstract: Apparatus for physicochemical separation and filtering constituents of fluids having a flexible leak-tight or semipermeable casing which tightly envelopes a filter material and inlet and outlet pipes for passing a fluid through the casing in contact with the filter material. The casing is made in a flat profile that can be formed into various shapes such as spirals, ribbons or the like.

Abstract: A sieving screen or filtration screen, and processes for producing the same, featuring the use of a flexible, chemical resistant, intermittent, polymeric coating as an edging material and/or for providing indicia for identification purposes to show, for example, the source of the product, producer's or customer's logos, trade names, part numbers, indications and precautions for use, and any other forms of instruction and/or information, as well as providing an intermittent or discontinuous coating to allow for electrical grounding with a conventional filter clamp or the like. Screen printing is one preferred method for applying the polymeric matter to the sieve or filter screen.

Abstract: A filtration cassette of a type comprising filter sheets arranged in a multilaminate, peripherally bonded array, wherein the filter sheets alternate with permeate and retentate sheets. A stacked assembly of such filtration cassettes may be employed to form a stacked cassette filter. The filtration cassettes and filter of the invention may be advantageously employed for dewatering of aqueous biomass suspensions, desalting of proteins, removal of secreted metabolites from cellular suspensions, and the like.

Abstract: An antimicrobial filter cartridge having a perforated core member wrapped with a first microporous membrane, which is in turn overwrapped with second and third microporous membranes. The membranes are covered with a criss-cross wrapping of antimicrobial treated yarn. The filter cartridge is sized so as to fit tightly into a cartridge housing of a fluid filtration system. Fluid passing through the cartridge housing will be filtered by the filter cartridge to remove microorganisms from the water and which prevents the growth of bacterial and other microorganisms on the filter media.

Abstract: The present invention provides a method and apparatus for separating a blood sample having a volume of up to about 20 milliliters into cellular and acellular fractions. The apparatus includes a housing divided by a fibrous filter into a blood sample collection chamber having a volume of at least about 1 milliliter and a serum sample collection chamber. The fibrous filter has a pore size of less than about 3 microns, and is coated with a mixture including between about 1-40 wt/vol % mannitol and between about 0.1-15 wt/vol % of plasma fraction protein (or an animal or vegetable equivalent thereof). The coating causes the cellular fraction to be trapped by the small pores, leaving the cellular fraction intact on the fibrous filter while the acellular fraction passes through the filter for collection in unaltered form from the serum sample collection chamber.

Abstract: Disclosed is a hub ring for a filter wherein a supporting member having a plurality of supporting portions is interposed between a pair of keep plates, a supporting plate for a filter wherein a plurality of wave portions extending substantially in the circumferential direction are arranged in the radial direction, and methods for manufacturing these members. The hub ring has a great opening ratio to achieve a low pressure loss property and causes substantially no residence of polymer, and the hub ring can be manufactured at a low cost. The supporting plate has high pressure resistance, low-pressure loss property, good directivity of polymer flow and excellent polymer mixing effect, and it is suitable for use as a retainer disposed inside of a filter.

Abstract: A filter element including a filtration part and a mounting frame retaining the filtration part therein. The frame is formed by a profile with a center part and two border parts. The filtration part is retained between the border parts. The border parts are positioned in generally parallel relation to each other. A strip of material is firmly fixed to the border parts such that one end of the strip is fixed to one of the border parts and an opposite end is affixed to the other of the two border parts. The strip is in generally parallel relation to the center part.

Abstract: Melt-blown fibrous webs having a uniform structure for use in processing biological fluids are disclosed.

Abstract: Disclosed is a hub ring for a filter wherein a supporting member having a plurality of supporting portions is interposed between a pair of keep plates, a supporting plate for a filter wherein a plurality of wave portions extending substantially in the circumferential direction are arranged in the radial direction, and methods for manufacturing these members. The hub ring has a great opening ratio to achieve a low pressure loss property and causes substantially no residence of polymer, and the hub ring can be manufactured at a low cost. The supporting plate has high pressure resistance, low-pressure loss property, good directivity of polymer flow and excellent polymer mixing effect, and it is suitable for use as a retainer disposed inside of a filter.

Abstract: A method for removing leukocytes from a leukocyte-containing suspension comprising passing said suspension through a filter including a nitrocellulose membrane having a pore size of 5-15 .mu.m.

Abstract: Filter apparatus for filtering contaminants from a fluid, such as machine tool coolant, are disclosed. One filter apparatus includes a filter drum unit having a generally cylindrical open perforated support sheet with a cylindrical screen element mounted thereabout. Circumference varying mechanisms, such as turnbuckles, are connected relative to the support plate to vary the circumference of the support plate and the tautness of the screen element. A disc filter assembly having a mandrel and fluidly attached annular disc filter elements is also described. Each annular disc filter element has an inner structure with concentric ribs forming concentric grooves therebetween which are connected to radially extending grooves. A screen element is supported by the ribs so that the microscreen will not tear while allowing filtering of fluid into the grooves which are in fluid communication with the mandrel.

Abstract: A filter unit (10) designed to filter process streams having different components and/or different fluid flow rates. The filter unit includes an elongated filter housing (12) having an inlet port (14) at one end and an outlet port (19) at the other end. A filter element flange (32) is fitted in the housing. The filter element flange is provided with a number of bores (34) that are provided with threading. Filter elements (28) with threaded coupling heads (36) are removably secured to the filter element array by fastening the coupling head in the threaded bores. This arrangement allows the replacement of the filter elements without having to completely disassemble the filter unit. In the event the number of filter elements is less than the number of openings that are in the element flange, plugs (84) are secured into the links in which the filter elements are not seated to prevent unfiltered fluid flow from the inlet port to the outlet port.

Abstract: A composite filter media for bag or pocket filters and the like includes an upstream dirt-holding layer of fine polymeric fibers and a downstream high efficiency filtration layer of glass fibers. The upstream layer includes polymeric microfibers having a mean fiber diameter ranging from about 2.5 to about 4.5 microns, lofting fibers and binder fibers; and weighs between about 2.0 and about 7.0 grams per square foot. The glass fiber layer has a weight between about 1.2 and about 2.7 grams per square foot; the average diameter of the fibers in the glass fiber layer is within a range from 3.0.times.10.sup.-5 to 4.1.times.10.sup.-5 inches; and the fibers are bonded together at their points of intersection with a binder. The composite filter media has an average air filtration efficiency of at least 80%.

Abstract: Filtration medium is formed of a mass of nonwoven melt blown support and filtration fibers which are integrally co-located with one another. The support fibers have, on average, relatively larger diameters as compared to the filtration fibers which are integrally co-located therewith. Preferably, the filtration medium is disposed within at least one annular zone of a filtration element, for example, a disposable cylindrical filter cartridge having an axially elongate central hollow passageway which is surrounded by the filtration media. A depth filter cartridge in accordance with the present invention may thus be formed having one or more additional filtration zones (which additional filtration zones may or may not respectively be provided with integrally co-located support fibers) in annular relationship to one another.

Abstract: An apertured film extruded from a crystalline, thermoplastic, extrudable fluoroplastic material. The film includes spaced-apart strand segments defining apertures therebetween and has at least 10 strand segments per inch. The film has a thickness of 2-12 mils and a Frazier air permeability number in the range of 200-2,000. The invention includes a process for preparing an apertured thermoplastic film by a single-sided embossing method. The process includes the steps of extruding in the machine direction, a film of a molten, crystalline, thermoplastic, extrudable, fluoroplastic material. The molten extruded film is passed in the machine direction through the nip of two metal rollers. One of the rollers has a substantially smooth surface, having a convex configuration as viewed from a direction substantially parallel to the axis of the roll, such that the diameter in the center of the roll is in the range of 8-12 mils greater than the diameter at the ends of the roller for a 40 inch roller.

Abstract: A filter membrane element for a membrane separation unit for use in a water treatment apparatus or the like, and a method of manufacturing the same. An organic filter membrane including a plate-like support member made of nonwoven fabric and a film coating formed on both sides of the support member is joined with a surface of a filter plate, whereby the filter membrane element is formed. A portion of the film coating is dissolved to cause the support member to be exposed at that portion. Subsequently, the exposed portion of the support member is joined by adhesion or otherwise with a corresponding portion of the filter plate.

Abstract: A filter device inserts into a duct having flow passing from upstream to downstream. The filter device includes fluted filter media having flutes formed therein inserting into a housing. The filter media is stacked and placed at an angle to the prevailing flow direction.

Abstract: An antimicrobial filter cartridge having a perforated core member wrapped with a microporous membrane, which is overwrapped with a spiral wrapping of an antimicrobial agent impregnated yarn. The spiral wrapping is covered with a criss-cross wrapping of yarn. The filter cartridge is sized so as to fit tightly into a cartridge housing of a fluid filtration system. Fluid passing through the cartridge housing will be filtered by the filter cartridge to remove microorganisms from the water and which prevents the growth of microorganisms on the filter media.

Abstract: The present invention relates to a method and to a device for separating plasma from whole blood. The method and device utilize a permeable non-glass fiber matrix containing a polyol which is capable of clumping red blood cells. The matrix, in the absence of such a polyol, would otherwise be porous to red blood cells. The polyol-containing matrix has a first surface and a second surface such that a whole blood sample which is applied to the first surface flows directionally toward the second surface. Plasma separated from whole blood becomes available at the second surface of the matrix and can be tested for the presence of a particular analyte, such as glucose or fructosamine, as provided by multi-layer test devices of the present invention.

Abstract: A filter assembly for use in an air remediation system is provided. The filter assembly includes a first and second filter member, each of which has a plurality of openings to define a plurality of separate flow passages. A granular filter material layer is disposed between the first and second filter members. A frame structure containing each of the first and second filter members as well as the granular filter material forms the self contained filter assembly.

Abstract: A filter element for filtering a particle-containing paint composition or a particle loading slurry composition which is a precursor to a particle-containing paint composition is provided. The filtration element comprises at least one filtration layer formed from woven polymer fibers and having substantially uniform pores and two spacer layers. The spacer layers have raised projections to create a space between adjacent spacer layers having contacting projections. The filtration element has a pleated or spirally wound configuration.

Abstract: A leukodepletion filter is provided including glass fiber filter pads and non-woven polyester fiber filter pads sealed within a filter housing. The filter is designed such that a fluid, such as whole blood, packed red blood cells, platelets or plasma, is conducted through the glass fiber filter pads before the non-woven polyester fiber filter pads. A method is further provided for leukodepleting a body fluid by filtering the body fluid through glass fiber filter pads and also filtering the body fluid through non-woven polyester fiber filter pads. After filtering, the body fluid is collected.

Abstract: The present invention relates to a method and to a device for separating plasma from whole blood. The method and device utilize a permeable non-glass fiber matrix containing a polyol which is capable of clumping red blood cells. The matrix, in the absence of such a polyol, would otherwise be porous to red blood cells. The polyol-containing matrix has a first surface and a second surface such that a whole blood sample which is applied to the first surface flows directionally toward the second surface. Plasma separated from whole blood becomes available at the second surface of the matrix and can be tested for the presence of a particular analyte, such as glucose or fructosamine, as provided by multi-layer test devices of the present invention.

Abstract: A thin metal foil disc etched on both sides in such a way as to form a crossover pattern of rectangular flow passages (or channels) spiraling out, in opposite directions, from the inner diameter to the outer diameter of the disc. In the preferred embodiment, these channels have a depth slightly greater than half of the disc thickness, creating an opening through the thickness of the disc at their points of intersection. This disc design, when stacked appropriately into a filter element, provides substantially lower flow losses than other existing designs. When used as a filter, it performs as an absolute surface filter featuring a tortuous flow path and high degree of porosity. When used as a surface tension device, it offers superior wetting and re-wetting characteristics.

Abstract: A method for removing leukocytes from a leukocyte-containing suspension comprising passing said suspension through a filter including a nitrocellulose membrane having a pore size of 5-15 .mu.m.

Abstract: A filtering appliance for cleaning cooking oil in a food fryer is designed and dimensioned for single-handed portable use in "hand-gun" fashion. The appliance has an elongate casing means with a hand grip at one end adjacent a pump-and-motor assembly. An intake nozzle conducts oil to be cleaned to a cartridge style filter made by stacking annular elements cut from a commercially available filter material of fibrous mat forming matrix holding particulate filtering media. The filter is axially spring loaded to accommodate yielding of the filter material. The appliance discharges into the food fryer through a duct outside the casing means. Thus, the oil is recirculated to achieve cleaning.

Abstract: A diesel engine secondary oil filter is formed from a punched tinned steel spiral lock seam center tube, with a flanged cap at one end and a flanged threaded outlet at the other end. A layer of polyester non-woven media is wrapped in one wind around the center tube. A yarn is wound is a 27-diamond pattern in a first yarn section out to two inches outer diameter. The yarn is tied off. Knitted socks are first placed partially on axial ends of the first wound section, leaving half of the socks extending over the ends. A sheet of activated carbon paper about 1/6 of an inch thick and about 52 inches long is rolled onto the filter cartridge with about nine turns. The carbon paper is made of a cellulose paper impregnated with about 50% activated carbon powder by weight.

Abstract: A computer drive bay cover with filter including a cover plate that has a front panel with a peripheral overhang. The front panel has a plurality of linear slots cut at a slant. The overhang has a pair of side portions with a pair of elongated projections for forming a rear channel. A filter sheet is positionable within the rear channel of the cover plate. Lastly, a rear panel is provided. The rear panel has an elongated rear edge that is hingedly coupled to the overhang. The rear panel has a bottom side with a plurality of pile-type fasteners that couple with a plurality of pile type fasteners affixed to a central processing unit housing. The rear panel is secured to the central processing unit housing for positioning of the cover plate, with the filter sheet, over a drive bay of the central processing unit housing.

Abstract: A filter of the type having first annular filter media comprising a generally columnar stack of annular filter media lamina for providing filtration for one circuit, a harness for retaining the filter media lamina in stacked columnar alignment comprising a generally circular end piece having a diameter somewhat greater than the diameter of the filter media lamina engaging one end lamina, an annular portion engaging the opposite end lamina, a plurality of elongated strips integral with and extending from the periphery of the annular portion with the end piece receiving and retaining the free ends of the elongated strips. There is a second filter media providing filtration for another circuit. The two filter media are housed adjacent to one another in a hollow cylindrical shell closed at one end. An annular retainer is integral with the shell near the other shell end for engaging the second media and retaining both media axially within the shell.

Abstract: The present invention provides an apparatus for separating a relatively large volume of blood into cellular and acellular fractions without the need for centrifugation. The apparatus comprises a housing divided by a fibrous filter into a blood sample collection chamber having a volume of at least about 1 milliliter and a serum sample collection chamber. The fibrous filter has a pore size of less than about 3 microns, and is coated with a mixture of mannitol and plasma fraction protein (or an animal or vegetable equivalent thereof). The coating causes the cellular fraction to be trapped by the small pores, leaving the cellular fraction intact on the fibrous filter while the acellular fraction passes through the filter for collection in unaltered form from the serum sample collection chamber.

Abstract: A membrane apparatus includes a bubble supplying portion for supplying micro bubbles which is provided at a location in the vicinity of the entrance of a flow passage for raw liquid. Thus, the growth of a gel layer on a membrane surface can be prevented, and a large filtering amount can be maintained while preventing sludge from blocking the membrane. Moreover, since bubbles uniformly pass through the inter-membrane passages, sludge blocking can be evenly prevented over the entire surface of the membrane. When a flat membrane is used as the filtering membrane, there is provided an advantage of reducing the frequency of work for disassembling the frame and cleaning the membranes. A membrane treatment apparatus includes the membrane apparatus, an aeration apparatus, a circulating tank, and a filtrate pump.

Abstract: The invention relates to a backwashable filter, which comprises superimposed elements, particularly having an annular design, for producing filter candles. In the case of the filter candles the elements are subject to a radial through-flow from the inside to the outside in filter operation, whereas the flow direction is reversed for backwashing. On the inside of the filter layer is provided on each element a lip, elastically deflectable in the flow direction and facing the flow, which forms a gap opening with a fixed edge of the adjacent element. Under the action of the differential pressure of the flow acting on the wide front face of the lip, the lip performs a movement in which the gap opening is narrowed to a limited extent and as a result of the elastic deformation corresponding restoring forces are built up.

Abstract: The disclosure describes an apparatus for treating fountain solution which comprises a recirculation assembly and a microporous filter assembly. The recirculation assembly is connected between the outlet and inlet of a fountain solution tray of a printing system. The recirculation assembly includes a fountain solution sump and a return line which extends from the outlet of the fountain solution tray to the sump. The microporous filter assembly is positioned in the sump or in the return line and includes a filter position across a fountain solution flow path. A pressure sensitive device is cooperatively arranged with the filter to bypass the filter in response to a predetermined pressure differential.

Abstract: A micropore filter of discrete flow-through pores of highly controlled pore configuration and dimensions is formed by bonding platelets into a laminate, each platelet having been etched, preferably by a combination of electropolishing and photoetching techniques, to form depth-etched passages and through-etched passages, respectively. The filter is housed in a module which contains wiper blades for periodically removing deposited debris from the filter surface.

Abstract: Disclosed is a hub ring for a filter wherein a supporting member having a plurality of supporting portions is interposed between a pair of keep plates, a supporting plate for a filter wherein a plurality of wave portions extending substantially in the circumferential direction are arranged in the radial direction, and methods for manufacturing these members. The hub ring has a great opening ratio to achieve a low pressure loss property and causes substantially no residence of polymer, and the hub ring can be manufactured at a low cost. The supporting plate has high pressure resistance, low-pressure loss property, good directivity of polymer flow and excellent polymer mixing effect, and it is suitable for use as a retainer disposed inside of a filter.

Abstract: There is provided a fiber bed for removing liquid aerosols and soluble solids from a gas stream in a fiber bed mist eliminator. The fiber bed is in the form of a flexible mat having a void fraction of greater than about 0.89 and greater than about 700 net collection targets. The mat includes a layer of collecting fibers having an average fiber diameter between about 1 and about 5 .mu.m. The collecting fibers are stabilized by a plurality of stabilizing fibers which penetrate into and are disposed interstitially within the collecting fiber layer. The improved fiber bed of the present invention is field-replaceable and, by utilizing fibers having a small average diameter, the thickness of the fiber bed may be reduced.

Abstract: A disposable device for filtration and collection of blood during a surgical operation, which device comprises a housing with a cup-shaped portion, in which a wall section is forming a ledge in the reservoir inside the housing. A first self-supporting filtration element for venuous blood is upstanding from the ledge, and a second filtration element for cardiotomy blood is suspended from the cover, the two elements being arranged side by side in a parallel relationship. The filter elements have an elongate, oval cross-section.

Abstract: An apparatus for extracting an analyte from a liquid sample, comprises a microcolumn having a microparticulate media therein, the media being sandwiched between two compression layers. Preferably, the compression layers comprise a binder-free glass fiber, held in the microcolumn by upper and lower polypropylene mesh.

Abstract: A filtration cassette, of a type comprising membrane filter sheets arranged in a peripherally bonded array of multilaminate character wherein the filter sheets alternate with foraminous (e.g., screen or mesh) sheet members, ribbed retentate sheet members, and a cross-flow filter comprising a multiplicity of stacked filtration cassettes of such type. The filtration cassettes and filter of the invention may be advantageously employed for dewatering of aqueous biomass suspensions, desalting of proteins, removal of secreted metabolites from cellular suspensions, and the like.

Abstract: A blood filtration device encapsulates a filter pad assembly Within a flexible housing. The filter pad assembly includes first and second filter media layers. A first heat and pressure sealed region integrally bonds the peripheries of the first and second media layers together. The flexible housing comprises a peripheral rim aligned with the first heat and pressure sealed region of the first media layer. A second heat and pressure sealed region, formed after the first heat and pressure sealed region, joins the rim of the flexible housing to the first heat and pressure sealed region, thereby forming a composite seal that encapsulates the filter pad assembly within the housing.

Abstract: Filtration medium is formed of a mass of nonwoven melt blown support and filtration fibers which are integrally co-located with one another. The support fibers have, on average, relatively larger diameters as compared to the filtration fibers which are integrally co-located therewith. Preferably, the filtration medium is disposed within at least one annular zone of a filtration element, for example, a disposable cylindrical filter cartridge having an axially elongate central hollow passageway which is surrounded by the filtration media. A depth filter cartridge in accordance with the present invention may thus be formed having one or more additional filtration zones (which additional filtration zones may or may not respectively be provided with integrally co-located support fibers) in annular relationship to one another.

Abstract: A backwashable filtration system comprises a plurality of filter cartridges each consisting of a column of stacked arcaded wafers disposed on a rigid geometric guide rod. The wafers have arcuate portions interconnected by straight portions to form a filtration portion. An upper and lower surface of the filtration portion has grooves disposed therein. The filtration portion is connected, via a plurality of tabs, to a mounting portion having an inner hexagonal cavity and a circular exterior. The inner hexagonal cavity is tightly toleranced to fit onto the rigid hexagonal guide rod so as to preclude rotation of the wafers about the rod. The relationship of the inner hexagonal cavity to the outer filtration portion ensures that the arcs will always align to each other and that the grooves on a top surface of a wafer will be offset from grooves on the bottom surface of an opposed wafer. Integral passages accommodate flow of filtrate to a clean chamber and accommodate the flow of backwash fluid through the stack.

Abstract: An edge filter for use with a variable-displacement pump control is disclosed. The edge filter comprises a first portion disposed between a source of hydraulic actuating fluid and an orifice having a first flow area. The first portion has an outer circumference defining a radial gap within a bore. The gap has a predetermined gap width less than a diameter of the orifice.

Abstract: A delivering member for filtering and delivering a sample to a test assay surface includes a prefilter having a sample receiving surface and a surface for delivering a sample to a test assay surface. The prefilter includes a diffusing material on its receiving surface for rapidly and evenly diffusing a sample across the prefilter receiving surface. In this way, a sample may be rapidly and evenly delivered to a test assay surface. A test assay solid phase has a surface including an area carrying an immobilized species and an area free of immobilized species. When a sample is applied to the surface, followed by application of a labeled species, the evenness of distribution of the labeled species is indicative of the evenness of application of the sample. A kit includes a delivering member and an assay surface.

Abstract: A filter for filtering particulates from a particulate-containing fluid stream passing through the filter, contains one or more flow plates, each of the flow plates having (a) one or more primary fluid flow passages; and (b) one or more particulates-collecting, eddy current-forming accumulation chambers communicating with the primary fluid flow passages; wherein the accumulation chambers are not situated in the primary fluid flow passages and, when the accumulation chambers contain particulates, the particulate-containing accumulation chambers do not impede fluid flow through the primary fluid flow passages.

Abstract: The present invention is an improved electrically conductive filter media particularly suitable for use in applications where static electricity must be dissipated. The filter media of the present invention comprises a microporous filtration layer having electrically conductive particles embedded therein. When attached to support media, this structure provides exceptional filtration efficiency while assuring a consistent and evenly distributed electrical pathway to ground.

Abstract: A stacked membrane disk module has a number of membrane disks interleaved with seal rings and includes a biasing subassembly for maintaining a compressive force between the membrane disks and interleaved seal rings so that the module can be repeatedly pressurized/depressurized. The membrane disks preferably include a central first aperture and a pair of second apertures which are radially spaced from the central first aperture. These apertures will thus be respectively registered when a number of such membrane disks are stacked between a pair of end plates so as to establish a central fluid passageway and a pair of second fluid passageways. A rigid perforated tube is positioned within the central fluid aperture and is connected to the end plates so that at least one of the end plates is capable of being axially displaced relative to the perforated tube. A biasing member (e.g.

Abstract: An oil filter has a cap screwed to the approximately upright arranged filter housing of the oil filter for the cleaning of lubricating oil, with a ring-shaped filter insert being detachably fastened on the cap and separating the outer inflow space from the inner flow-off space. In the lower zone of the filter housing, provision is made for a valve-like acting member, which is automatically opened with each change of the filter insert and serves for discharging oil that remained in the filter housing into an oil-collecting space via a discharge duct. A center bar is rotatably connected with the cap. The center bar is axially displaceable in a limited way and has in its zone close to the cap a piston-like flange, which is sealed against the filter insert and separates the inflow space from the flow-off space. The center bar has, in its lower end zone, the valve-like acting member cooperating with the discharge duct.

Abstract: Disclosed is a hub ring for a filter wherein a supporting member having a plurality of supporting portions is interposed between a pair of keep plates, a supporting plate for a filter wherein a plurality of wave portions extending substantially in the circumferential direction are arranged in the radial direction, and methods for manufacturing these members. The hub ring has a great opening ratio to achieve a low pressure loss property and causes substantially no residence of polymer, and the hub ring can be manufactured at a low cost. The supporting plate has high pressure resistance, low-pressure loss property, good directivity of polymer flow and excellent polymer mixing effect, and it is suitable for use as a retainer disposed inside of a filter.