Abstract: A filter arrangement with a cellular structure in which a plurality of filter chambers extend in the direction of the medium to be filtered. There is a filter cloth or fabric attached to each of the two sides of a cell frame which closes the filter chambers on both sides. The filter chambers are each provided with a filling of predominantly active charcoal granules. To achieve a simple and advantageous structure of the filter arrangement, the cellular structure is in the form of a rectangular cell frame each with rectangular filter chambers, preferably made of synthetic resin. Appropriate, right-angled partition walls inside the cell frame and the installation of reinforcement members can result in filter chambers of optimum size.

Abstract: In a process for the manufacture of a strip material (1) a plastics layer (5, 6) is formed at least on one side of a support (2) from a mixture of plastics materials and particulate soluble corpuscles wherein the soluble corpuscles are leachable by a solvent of a type against which the plastics material is stable. Thereafter the soluble corpuscles are leached out from the plastics layer (5, 6) with the formation of throughflow passages. According to the invention, a plastics powder is prepared as the plastics material, which is mixed with the soluble corpuscles and applied onto the support (2). By heat and pressure treatment a plastics layer (5, 6) including therein the soluble particles, is produced from the mixture of plastics powder and soluble corpuscles, prior to the soluble corpuscles being leached at least in part out of the plastics layer (5, 6).

Abstract: The water filtration system has nine filter elements serially arranged in a hollow cylinder housing with a water inlet end and water outlet end having pipe fittings, such as, 3/4 inches for installation in the main inlet water line of a household. For a normal household the housing is approximately 20 inches long and 4 inches in diameter. The first filter element on the water inlet end is a loose weave polyester fiber pad; the second filter element is multiple irregular polyethylene beads filling approximately 3 inches of the housing length; the third and seventh filter sections are a very fine plain wool filter floss; the fourth, sixth and eighth filter sections are one millimeter wool fibers impregnated with carbon to equal two thirds of the total weight of the fibers; the fifth filter element is multiple pharmaceutical grade carbon granules filling approximately 4 1/2 inches of the housing length; and the ninth filter element is a fine mesh nylon screen.

Abstract: Resin having a susceptibility to electrostatic charge which is opposite in polarity to the susceptibility to electrostatic charge of a filter sheet or member forming a filter element is impregnated into the filter member. For example, when the filter member is composed of polyester of 50-70 weight percentage and glass fiber of 5-25 weight percentage as well as pulp of 15-35 weight percentage, resin composed of phenol resin of 5-20 weight percentage and melamine resin of 80-95 weight percentage is impregnated into the filter member so that the susceptibility to electrostatic charge of the filter member can be neutralized. Thus, static electricity generated by friction between the filter element and fuel flowing therethrough can be controlled.

Abstract: A ceramic filter containing at least one functional material and method of manufacturing, a ceramic filter whose surface through which a liquid to be purified flows into is densest and the average particle size of the filter continuously increases toward the interior thereof, a method of manufacturing the ceramic filter including ultrasonic vibration, an extrusion molding die used to manufacture the ceramic filter and an extrusion molding apparatus using the die.

Abstract: The subject matter of the present invention is a device for purifying lightly laden water containing particles and/or fatty matter and/or microorganisms in suspension. The device of the invention is a filter comprising a grid (1) on which is placed a filter element (3) consisting of at least one sheet based on fibers and filled with organic and/or inorganic powders. The invention finds its application in all the industries which consume water and especially the crude oil processing industries and the chemical, papermaking and agri-foodstuffs industries.

Abstract: Blood filtration devices and methods of filtering are disclosed. In part, a blood filtration device is provided comprising a housing defining an interior periphery. The device includes a rotating structure mounted within the interior periphery and defining with the housing an annular gap within the interior periphery, an inlet fluid path for allowing a blood product to flow into the annular gap, and the rotating structure including an exterior surface that includes a filter membrane. The filter membrane has a coating thereon comprising an insitu condensation product of a first electrophilically active, high molecular weight polyalkylene oxide and a second high molecular weight bifunctional diamino-polyoxyalkylene oxide derivative.

Abstract: The present invention encompasses novel coated particles that are well suited for use as absorption media in chromatographic processes. The coated particles comprise a substrate, such as aluminum, silicon, titanium or zirconium oxide particles, containing polymerized silane moieties on a surface of the substrate. The silane moieties include two or three olefinic groups as well as at least on useful ligand. Methods of preparing these coated particles are also described.

Abstract: A fiber filter, method of preparing the fiber filter, and method of treating a fluid stream with the fiber filter are disclosed. The fiber filter comprises an inert fiber matrix, water, and a substrate bound to the fiber matrix that is capable of oxidizing or neutralizing a contaminant. More specifically, the substrate bound to the fiber matrix is sodium bicarbonate, impregnated activated alumina, impregnated zeolite, or a mixture thereof. The impregnate is a permanganate salt, sodium bicarbonate, or a mixture thereof. Improved efficiency of removal of undesirable compounds such as hydrogen sulfide and sulfur dioxide from fluid streams is achieved.

Abstract: The present invention relates to a process for producing polymer beads incorporating solid particles and to the novel polymer beads per se. The invention provides a process for producing polymer beads incorporating solid particulate material, which process comprises producing a dispersion having a dispersed phase including one or more monomers also including solid particulate material, and causing said one or more monomers to undergo a polymerization reaction to form said polymer beads, wherein said dispersion further includes a solid phase dispersing agent for dispersing solid particles of material in the dispersed phase and wherein said solid phase dispersing agent reacts with at least one monomer to thereby become chemically incorporated in said polymer. The polymer beads comprise a polymer matrix having solid particulate material dispersed substantially uniformly therein and wherein the polymer matrix incorporates a solid phase dispersing agent chemically reacted into the polymeric matrix.

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: 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: Magnetic particles which comprise a core of a magnetic material surrounded by a mixture of a fibrous material and a solid binding agent. The particles may be embedded in a polymer resin which incorporates sites, which are selective for particular ions, to form composite magnetic resin particles. The composite magnetic resin particles may be used for the removal of pollutant ions from an aqueous solution in which they are contained.

Abstract: A chemically charged-modified filter for removing charged, micron to sub-micron sized particles from an aqueous liquid, the filter being composed of a filter sheet having a plurality of individual exposed surfaces, at least a portion of which having a surface energy of less than about 45 dynes per centimeter; amphiphilic macromolecules adsorbed onto at least some individual exposed surfaces having a surface energy of less than about 45 dynes per centimeter; and chemical charge modifiers incorporated onto at least a portion of the amphiphilic macromolecules; so that when said charge-modified substrate is in contact with the aqueous liquid containing the charged, micron to sub-micron sized particles, said particles are adsorbed onto the chemically charge-modified filter.

Abstract: The present invention relates to a mineral eluting material for drinking water with granite as raw material and manufacturing method thereof and a structural body of mineral eluting material. The mineral eluting material includes granite crushed to sizes of 0.075.about.0.145 mm, submerged in 3.about.10% glucose solution for 24 hours, baked at 380.degree..about.400.degree. C. for 12.about.24 hours, and cooled at room temperature in a tightly sealed vessel. The structural body according to the present invention is manufactured by piling up granular granite and silver activated charcoal in 2-10 layers respectively and alternately in a cylindrical column. Water having passed the structural body according to the present invention comprising granular granite contains no impurities and abounds in minerals.

Abstract: A homogeneous mixture of a base and a binder material or fiber that is compressed to form a mat or sheet of selected porosity. The binder material has at least a surface with a melting temperature lower than that of the base fiber. The sheet is formed into a selected geometric shape and thermally fused to bind the base fiber into a porous filter element. The preferred shape is a helically wound tube of plural sheets, each sheet being self-overlapped and compressed to overlap another sheet. Each sheet preferably heated and compressed individually and the sheets may be selected to have different porosities and densities. The binder fiber is selected from the group consisting of thermoplastic and resin, and the base fiber is selected from the group consisting of thermoplastic and natural.

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: Novel blood cell fractionation means utilizes conventional filters coated with high molecular weight polyethylene oxide derivatives crosslinked to prevent leaching from filter surfaces. These fractionation means have a special efficacy in binding white blood cells from whole blood while simultaneously allowing red cells and platelets to pass in the effluent phase.

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: A flexible, multi-layer filter for separating solid and liquid wastes. In a preferred embodiment, the filter includes first, second, third, and fourth layers, interconnected by appropriately spaced connectors. The first layer comprises sub-layers of parallel strands, wherein the strands in one sub-layer cross and overlap the strands in the other sub-layer to form a netting. The second layer comprises a fibrous mat, and the third layer comprises a netting like that of the first layer. The fourth layer includes a porous filter cloth. The third layer may be cut to form end and side tabs for retaining the filter inside a conventional waste container. After a semi-solid mixture of waste is poured, dumped, or otherwise placed into the waste container, liquid waste passes through the filter layers under the force of gravity. The liquid waste is channelled through the first layer along the bottom of the waste container.

Abstract: A bonded multi-component filter medium preferably contains at least two active components, namely, activated carbon adsorbent and a blend of at least two organic polymer absorbents. The medium is prepared by adding a selected quantity of carbon of a preselected size to a mixer, then wetting the activated carbon with a water-based aliphatic resin binder adhesive, preferably also with a surfactant, thus eliminating the static charge on the carbon, then adding hydrophobic absorption bonding polymers to the mixer, then thoroughly mixing the hydrophobic absorption bonding polymer with the carbon in preselected proportions, until both the carbon particles and the polymer particles are effectively coated with the binder adhesive. After thoroughly mixing, the medium mixture is preferably poured into filter cartridge forms, and then air-dried at room temperature and low humidity, to cure the aliphatic resin adhesive binder.

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: 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: The present invention provides a fiber-reinforced porous plastic tube which is essentially composed with fibers having a high tensile modulus such as glass fibers and a matrix resin such as polyethylene, and has continuous pores, and excellent mechanical strength. This porous tube is useful for structural materials in a building and/or construction, filters, diffusing tubes, drain materials and the like.

Abstract: A cylindrical filter is disclosed which comprises a wound up layer of a fibrous aggregate comprising melt-adhesive composite fibers bonded each other through the melt of a melt-adhesive component in the composite fibers and a layer of non-woven fabric of glass fibers, the layer of non-woven fabric is arranged on the outer surface of the wound up layer of the fibrous aggregate, and glass fibers have a smaller diameter than that of the melt-adhesive composite fibers. The cylindrical filter has an excellent filter rating and filter life.

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 drinking straw that purifies water by forced movement of water through the straw. The straw is composed of: 1) a filter plug made of a fibrous structure, the filter plug having sides, a first end, a second end, and a firmness sufficient to avoid collapse of the fibrous structure under a specified pressure drop; 2) a water purification material integrated in the fibrous structure; and 3) a liquid impervious wrapper covering the sides of the filter plug, the wrapper defining openings at the first and second ends of the filter plug.

Abstract: An adsorbent body having a porous structure for purifying a fluid, wherein the porous structure comprises activated carbon, and an inorganic binder for bonding together grains of the activated carbon. The porous structure optionally comprises activated alumina. The adsorbent body is produced by: preparing a raw material composition including a source material which gives activated carbon, aluminum hydroxide which gives activated alumina (Al.sub.2 O.sub.3), and an inorganic binder for bonding together grains of the activated carbon and the activated alumina; forming an unfired shaped body of the raw material composition; and firing the unfired shaped body at a predetermined sintering temperature to produce the adsorbent body.

Abstract: A material for removing human immunodeficiency virus (HIV) and its related substances from blood, plasma, or other body fluids is provided. The material comprises a porous substrate on which sulfuric group substantially in the form of a salt is immobilized. A convenient removal of HIV and its related substances at a high efficiency is enabled by the use of the material.

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: Novel blood cell fractionation means utilizes conventional filters coated with high molecular weight polyethylene oxide derivatives crosslinked to prevent leaching from filter surfaces. These fractionation means have a special efficacy in binding white blood cells from whole blood while simultaneously allowing red cells and platelets to pass in the effluent phase.

Abstract: A process for preparing a composite particulate material, comprising the steps of providing a particulate primary material having a primary softening temperature; providing a particulate support material having a support softening temperature; providing a particulate binder material having a softening temperature which is less than the primary softening temperature and the support softening temperature; mixing the primary material, the support material and the binder material so as to provide a substantially uniform mixture; and heating the mixture to a temperature greater than or equal to the softening temperature of the binder material and less than the primary softening temperature and the support softening temperature, whereby the binder material binds the primary material to the support material so as to provide a composite particulate material.

Abstract: A multi-layer microfiltration membrane having an integrated prefiltration layer. Pursuant to a phase inversion process, several layers are successively poured out onto one another prior to phase separation of a lower layer, with the viscosity for the pour solution decreasing toward the upper layers. This produces a microporous, multi-layer, integral filtration membrane having a homogenous symmetrical pore structure for the final filtration layer and an open-pored structure for the prefiltration layer disposed therebelow. Even with small pore diameters, this membrane can be easily pleated for installation in filter cartridges without the formation of damage at the crease edges. High throughput rates are possible at a low tendency to clog.

Abstract: A filter material for removing chlorine from cold water used in preparing a human-consumable beverage having at least one layer of a mat of laid fibers of cellulosic fibers and synthetic textile fibers and mixtures thereof. A synthetic hydrophilic, food-grade latex binder deposited onto the fibers within the mat in an amount sufficient to so bind the fibers together within the mat that during a filtration of cold water through the mat no substantial amount of fibers are displaced therefrom and in an amount insufficient to substantially reduce a gravity flow rate of cold water through the mat to less than about 0.3 liter per minute per 100 square centimeters of the mat. A water-insoluble chlorine adsorbent or absorbent solid powder disposed on the binder such that no more than 65% of the total outside surface area of the powder is substantially contacted by the binder.

Abstract: A mechanically compacted composite article comprising a PTFE fibril web that entraps particles retains more of its longitudinal dimension, when subjected to mechanical and/or thermal stress, than a similar but non-mechanically compacted article.

Abstract: Disposable paper filters suitable for removal of contaminants from fluids such as water or air are disclosed. Specific embodiments include single-ply and multi-ply filters in which metal removal additives and/or halogen and organic contaminant removal additives have been distributed during the manufacturing process. Special manufacturing methods for producing such composite filters are also described.

Abstract: This invention provides a composition, device and method for the removal of selected factors, such as cytokines or pharmaceuticals, from a substance such as whole blood or plasma. Advantageously, the invention provides for the treatment or prevention of septic shock syndrome or other conditions evidenced by the presence of cytokines in a patient by contacting the patient's whole blood with a composition comprising silica and a surface treatment material, such as heparin, but preferably human serum albumin (HSA). The treatment lowers the cytokine concentration of the blood. Pharmaceuticals can be removed from an individual's whole blood or plasma, such as for use in treating drug overdosage.

Abstract: A filtering medium which is unchanged in the maximum pore size even when heating sterilization, high temperature filtration, etc. are carried out, yet has a high tensile strength, can be processed into pleat-form and also is applied to high precision filtration, is provided, which filtering medium is a product having a non-woven fabric composed of 20 to 80% by weight of lower melting point microfine fibers and 80 to 20% by weight of higher melting point microfine fibers having a melting point higher by 10.degree. C. or higher than that of the lower melting point microfine fibers, the respective fibers being hot-melt-adhered to one another through the lower melting point microfine fibers, hot-melt-adhered to a hot-melt-adhesive net, and having a maximum pore size of 120 .mu.m.

Abstract: A filter material for filtering leucocytes from a fraction of or whole human blood, comprises a web having a thickness of at least about 1 millimeter and a bulk density of about 0.05 to 0.4 g/cm.sup.3. The web has a plurality of interlocked matrix fibers distributed in the web to form a matrix thereof with spaces between adjacent interstices of interlocked fibers. The matrix fibers are composed mainly of about 1 to 3 micron diameter glass fibers, i.e. at least 75% of the weight of the web being the glass fibers. A plurality of fibrillated particles of textile fiber material, having a surface area of between 5 and 100 square meters per gram are disposed within the spaces of the matrix. The weight ratio of the fibrillated particles to the matrix fibers is between about 1:99 and 40:60. A thermoplastic binder is disposed at least at cross-over portions of the matrix fibers, with the amount of the binder being about 0.1% to 10% by weight of the web.

Abstract: A filter element intended for tangential-flow filtration has an elongated support body of porous ceramic material with coaxial channels running through the support body and provided on their surface with a ceramic membrane having a calibrated pore structure. A portion of the fluid flowing through the channels penetrates the membrane and exits as filtrate at the circumferential surface of the support body. The shape of the outwardly facing channel wall is adapted to the external shape of the support body and there it has a uniformly thick wall corresponding to the mechanical stress. The shape of the channel walls is configured such that the webs remaining between the channels flare outwardly wedge-wise. The filter element thus configured has a support body with a reduced resistance to the passage of the filtrate flowing through it.

Abstract: A method for inhibiting the growth of microorganisms on sorbents selected from the group consisting of absorbents and adsorbents that are susceptible to undesirable microorganism growth when exposed to water containing such organisms, said method comprising passing water to be treated by said sorbent over brass particles prior to or concurrently with contacting said sorbent with said water, the contact with the brass particles being sufficient to inhibit the growth of microorganisms on said sorbent while not releasing more than 1 ppmw copper ions and 5 ppmw zinc ions into the effluent water. Also disclosed are related sorbent elements and pretreatment packets used in said method.

Abstract: A hollow polysulfonic fiber intended for a selectively transmissive membrane contains a hydrophilic polymer which is cross-linked into a water-insoluble form (for example polyvinylpyrrolidone) and is used in the form of a hydrogel containing water. A method for the production of a membrane module consists in spinning a hollow fiber by the use of a spinning solution containing a polysulfonic resin and a hydrophilic polymer, wetting the fiber above the saturated moisture content, and then, with the wet condition maintained, subjecting the fiber to the processes of module molding and radiation induced cross-linking, these processes being performed in either order. The method provides a selectively transmissive hollow polysulfone fiber membrane which displays less elution into water and a sharp molecular weight fractionation, so as to be usable safely in the fields of medicine and foodstuffs.

Abstract: A composite membrane comprises an inorganic support having interstices and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof. The support is preferably a woven metal mesh, with the films substantially coplanar with the support. The films may be formed by applying a suspenion of refractory particles in a polymer solution to bridge the interstices of the support, and heating the films to partly sinter the particles. Since the films are in compression at ambient temperature, any cracks that may be formed by damage to the composite membrane tend not to propagate.

Abstract: Colloidal matter is removed from a fluid flow by first adsorbing a coagulant onto the surface of a finely divided filter media, and thereafter passing a colloid-containing fluid through the filter media. The adsorbing of coagulant is accomplished with the filter off-line, and it is returned on-line for filtering of the fluid. After the coagulant is adsorbed onto the filter media, it is not necessary to continue feeding coagulant during on-line operation, as the adsorbed coagulant captures the colloidal matter in the fluid and retains it on the surface of the filter media. The captured colloidal matter is removed during back washing of the filter media.

Abstract: A process for separating and recovering serum and plasma components from a whole blood sample including passing a whole blood sample through a separating filter formed of a blood cell separating layer composed mainly of fibers impregnated with a coating agent. A device includes a blood collector having a needle at one end and a blood suction means at the other end, and a separating filter including a blood cell separating layer, the filter being provided in the intermediate zone of the blood collector, whereby a whole blood sample sucked through the needle by depressurizing the blood suction means is passed through the separating filter.

Abstract: A method and adsorbent for increasing the life of edible oils are disclosed. The present method comprises substantially continuous treatment of edible oil with activated carbon during processes carried out at elevated temperature. The treatment may be by filtration through a filter means containing activated carbon or by immersion within the oil of an oil porous enclosure containing activated carbon. An adsorbent for substantially continuous use at elevated temperature is also disclosed. The adsorbent includes antioxidant impregnated activated carbons.

Abstract: A depth filtration method employing a depth filter media sheet, a method of forming the depth filter media sheet and the structure of the depth filter media sheet are described wherein the depth filter media sheet is formed from a wet strength layer and a filter septum layer, the filter septum layer being substantially thicker than the wet strength layer and being formed as a matrix from at least one fiber selected to provide substantial loft and pore structure throughout the filter depth of the filter septum layer, the wet strength layer and the filter septum layer being arranged adjacent each other and preferably bonded together with a lateral surface of the filter septum layer being substantially totally exposed for receiving fluid to be filtered with the porous matrix of the filter septum layer being available to receive and capture particulate solids from the fluid, the filter septum layer also preferably including a second fiber or additional fibers selected in combination with the first fiber for defin

Abstract: A novel filtration medium, preferably of the closed loop belt type, comprising a woven substrate which is overlaid by a disparate layer comprising a plurality of individual thermoplastic resin particulates which are controllably spaced apart from one another and bonded at fixed spaced apart locations to one to another and to the strands of the woven substrate. These resin particulates serve to define the pore structure and pore size for the medium. A method for the manufacture of the filtration medium is disclosed.

Abstract: A filter material for filtering leucocytes from a fraction of or whole human blood, comprises a textile web having a thickness of between about 2 millimeters to about 12 millimeters and a bulk density of about 0.05 to 0.4 g/cm.sup.3. The web has a plurality of interlocked textile fibers with average deniers between about 0.05 and 0.75 and average lengths between about 3 millimeters and 15 millimeters. The textile fibers are distributed in the web to form a matrix thereof with spaces between adjacent interstices of interlocked fibers. A plurality of fibrillated particles of textile fiber material, having a surface area of between 5 and 100 square meters per gram are disposed within the spaces of the matrix. The weight ratio of the fibrillated particles to the textile fibers is between about 1:99 and 40:60. A plurality of glass fibers, having an average diameter of between 0.1 and 5 microns and being about 2% to 85% of the web, also form part of the matrix.