Abstract: A process is provided for modifying the properties of a hydrophobic microporous membrane which includes the steps of first providing a hydrophobic microporous membrane, treating it with a surfactant to render the membrane hydrophilic, wetting the membrane with an aqueous solution of a polyol such as polyvinyl alcohol (PVA) and divinyl sulfone (DVS) or a precursor thereof, washing the membrane with water to displace the polyol/DVA from the exterior of the membrane while retaining it in the pores of the membrane, and crosslinking the polyol/DVS into an aqueous gel to yield a hydrophilic microporous membrane having pores filled with an aqueous polyol/DVS gel, the exterior of the membrane being unobstructed by gel. The modified membranes produced according to the process are useful in carrying out chromatographic separations.

Abstract: A composite structure, particularly a filter structure, is provided comprising a support having a surface and a porous membrane formed integrally to the surface of the support. The support preferably includes means for directing a fluid away from the surface of the support. The support surface is at least slightly soluble in a solvent. The porous membrane comprises a resin soluble in the solvent and precipitated while the casting solution is in contact with a porous substrate and the surface of the support. The membrane is formed and integrally secured to the surface of the support contemporaneously.

Abstract: Improved polymeric membranes and their method of manufacture are disclosed. The improved membranes are produced by increasing the draw ratio employed during the manufacture of the membrane. The membranes show at least substantially constant or increased selectivity and mechanical properties as the draw ratio is increased.

Abstract: Dopable, fully dense polymer membranes are used to form membranes having selective permeabilities. To improve selectivity, the membranes may be subjected to chemical or electrochemical treatment with electron donors or acceptors to alter the doping level of the polymer membrane, generally in a reversible fashion. This leads to significant changes in gas permeation rates relative to what is observed for the non-doped, fully dense polymers. This change in doping level of the polymer films can be precisely controlled by varying the concentration and nature of chemical dopants used. Desirable changes in permeation rates are achieved by a treatment which comprises a reversal doping of the polymeric material, followed by removal of the dopants (to provide an "undoped" polymer).

Abstract: A composite membrane and process utilizing the membrane which is capable of selectively removing particles such as viral particles from a solution such as a protein solution is provided. The membrane comprises a porous membrane substrate, a surface skin having ultrafiltration separation properties and an intermediate porous zone between the substrate and the skin which intermediate zone has an average pore size smaller than that of the substrate. The intermediate zone is free of voids which break the skin and which directly fluid communicate with the substrate. The composite is capable of a log reduction value of at least 3 (99.9% removal) of particles selectively from solution.

Abstract: A method for manufacturing a filter cartridge by polymerization of a polyethylene hydrocarbon with granular elements are set forth. The method involves the preparation of a mixture comprising the hydrocarbon and the granular elements, then introduction of the mixture into a mold which is formed by a first porous wall and a second porous wall, these walls being connected to a jacket, the introduction of the mold in an oven so as to raise the temperature of the mixture and by a thermal polymerization reaction to transform the hydrocarbon into a material binding the granular elements of the mixture, the assembly of the material and granular elements then forming a cartridge, and injection of a chemically inert gaseous composition into the mold through one of the walls to impart fluid permeability to the cartridge.

Abstract: Filter cartridge, in particular with a block-like shape, having a plurality of fold walls created by folding a permeable filter medium in a zig-zag fashion and which is provided with offsets formed by scoring so that a medium to be filtered passes through from one edge area of the zig-zag folding in the direction of the edge area of the folding on the opposite side. The offsets of adjacent fold walls which face one another contact each other as spacers and the filter medium is at least hardenable in the region of said offsets under the influence of heat. The permeable filter medium has fibres of thermoplastic material and the configuration of the fibres becomes more compact. The rigidity of the filter medium is increased by the welding of the filter medium under the influence of heat in the region of the offsets.

Abstract: A silica glass filter comprises a porous support body composed of amorphous silica particles as a porous sintered body and having a purity of 99.9% or more and containing 150 ppm or less in total of impurities including alkali, alkali metal, heavy metal and/or elements of III B group, and a filtration layer formed on the support body. The filtration layer is composed of amorphous silica particles as a porous sintered body in a fine mode and has substantially the same purity as that of the support body.

Abstract: The present invention is directed to an improved reverse osmosis membrane that shows surprisingly improved solute rejection and permeation properties. The membrane includes a separating layer of a polyamideurethane formed in situ by reaction of a haloformyloxy-substituted acyl haldide with a diamine-treated substrate.

Abstract: In the method of making a filtration unit, envelope-shaped membrane units (62) are placed in a stack, a curable liquid binder (101) is introduced between the membrane units from at least one surface of the filtration unit to a predetermined depth (a), and upon curing of the binder a layer of the binder together with the marginal portions of the edges of the membrane units embedded therein is removed, such as by surface cutting or machining, up to a depth (b) smaller than the depth (a).

Abstract: A method of manufacturing a filter element comprises the steps of mechanically crushing two grades or more of a heat resistive synthetic resin material, the grades having different melt flow indices, respectively, the heat resistive synthetic resin material being selected from the group consisting of polysulfone, polyethersulfone and polyphenylenesulfide or containing said selected heat resistive synthetic resin as a main constituent, mixing them with one grade of them being 20 to 80 wt %, sintering the mixture in a metal mold at a melt temperature thereof plus or minus 10.degree. C. when the mixture is crystalline resin or at a temperature in a range from glass transition temperature thereof up to the glass transition temperature plus 40.degree. C.

Abstract: Filter cartridge, in particular with a block-like construction, comprising a plurality of fold walls created by folding in a zig-zag fashion for a medium to be filtered to pass through from one edge area of the zig-zag folding in the direction of the edge area of the folding on the opposite side made of a material which can be permeated by the medium to be filtered provided with offsets formed by roll forming, with those offsets which lie in contact with each other acting as spacers and stiffeners between adjacent fold walls, wherein the offsets of adjacent fold walls which face one another are stuck together.

Abstract: A filter element which is improved in filter performance and suitable for use in various types of filters, and a manufacturing method thereof. In the filter element, a multiplicity of tubes each formed of a filtering material and having a substantially circular shape in cross-section are arranged side by side into a tubular assembly with the axes of the tubes lying parallel to one another; inter-tube openings are closed at one end of the tubular assembly which end serves as the inlet side for a fluid to be filtered, whereas intra-tube openings are closed on the opposite end of the tubular assembly; and the total cross-sectional area of all the inter-tube openings is set smaller than the total cross-sectional area of all the intra-tube openings, but larger than the minimum cross-sectional area of a path through which the fluid is supplied to the tubular assembly.

Abstract: A pleated paper filter element is disclosed which is formed from a mechanically-treated filter paper (10') which has the side thereof opposite to the wire-side (12) mechanically teased so as to form thereon an open, textured layer (18) of raised fibers. The starting material used is a standard, commercially-available filter paper which is resin-impregnated with an uncured phenolic resin. The pleated paper filter element formed from the treated filter paper (10') displays, after the element has been heated to cure the resin, a substantial increase of up to 73.5% in the dust-holding capacity over a like element formed from the standard, commercially-available filter paper.

Abstract: The invention includes a filter element (10) having a pair of end caps (12) with pleated, corrugated filter media (14) spanning therebetween. The filter media (14) is sealed or potted into the end caps (12) with a potting material ( b 16). To ensure substantially uniform penetration of the plates of the media (14) by the potting material (16), the edges of the media (14) are configued to eliminate "linear check valve" action between pleats. Several edge patterns can be used to minimize the formation of linear check valves, including a saw tooth pattern; sine wave pattern; vertical edge corrugations; flat edge regions; and saw kerfs in the edges of the media.

Abstract: A method of forming a composite material by providing a quantity of first particles of a binder material and a quantity of second particles of a primary material having softening temperature substantially in excess of the softening temperature of the binder material. The first and second quantities of particles are combined into a substantially uniform mixture. The uniform mixture is heated in the absence of pressure or shear sufficient to convert the binder particles, to a temperature substantially above the softening point of the binder material but less than the softening temperature of the primary material. Thereafter, pressure and shear are applied to the heated mixture sufficient substantially immediately to convert at least a portion of the binder material particles into a substantially continuous webbing structure or force the formation of point-bonds.

Abstract: The specification discloses a double shell filter comprising an inner shell of bounded 80 to 400 U.S. mesh screen carbon particles and an outer shell of bonded 20 to 80 mesh screen carbon particles wherein the inner and outer particles are bonded internally to each other and the two shells are bonded together preferably by an ultra high molecular weight polymer binder having a melt index of less than about 1 gram per ten minutes as determined by ASTM D1238 at 190 degrees C. and 15 kilograms load.

Abstract: Polymeric affinity membranes comprise a precursor filtration membrane and a plurality of reaction sites provided on the surface of the membrane selective to binding a specific biological material. A process for the preparation of such affinity membranes includes the steps of providing a copolymer compatible with a water insoluble polymer matrix and having a plurality of hydroxyl groups, activating the hydroxyl groups with a compound selected from the group consisting of organic compounds reactive with a hydroxyl group in the presence of a water miscible solvent to provide a derivatized copolymer containing active adducts, forming a solution of the derivatized copolymer and the polymer matrix to form a polymer blend solution, casting the polymer blend solution and, quenching the cast polymer blend solution in water.

Abstract: A fluid filter and methods for manufacturing same are described. The fluid filter includes: a filter element; a plastic housing for the filter element; and a plastic closure member including fluid inlet holes, each having an axis which is angled outwardly relative to the longitudinal axis of the filter housing. The closure member and the housing can be connected by welding, or the housing and the closure member may include complementary interengageable locking means for engagement. One method of manufacture includes the steps of forming a plastic housing and closure member and spin welding them together. Another method includes the steps of: forming the housing and closure member with complementary interengageable locking members; aligning the locking members; and turning the housing to engage the housing and the closure member. With either method, the assembled filter is then spun onto a threaded stud on a filter mount.

Abstract: A method for designing and making composite membranes having a microporous support membrane coated with a permselective layer. The method involves calculating the minimum thickness of the permselective layer such that the selectivity of the composite membrane is close to the intrinsic selectivity of the permselective layer. The invention also provides high performance membranes with optimized properties.

Abstract: Cellular glass structures are made by foaming select silicone resins. A foaming agent is reacted together with the silicone resin to form a foam that carries the resin as a continuous separate phase distributed throughout the foam. The foaming agent is removed by decomposition, and the remaining silicone resin is crosslinked to retain the foamed structure. The silicone resin is then heated in a non-oxidizing atmosphere at a temperature that will pyrolize the resin. During pyrolysis, the resin densifies to foam a unique glass composition comprised of silicon, oxygen and carbon, where carbon is chemically bonded to silicon, but there are essentially no chemical bonds between carbon and oxygen.

Abstract: An improved filter assembly of the type having a housing with an inlet, an outlet,and a passage in fluid communication with the inlet and the outlet, a filter media disposed within the passage, and at least a first filter element mounted on the housing which includes a porous member extending transversely across the passage adjacent a first end portion of the filter media. The porous member is pleated in order to provide increased surface area for a given cross sectional area of the passage. The filter element includes an annular support member having an opening and a pleated porous member mounted on the support member so that a plurality of pleats extend transversely across the support member. A method of fabricating the filter element includes providing the annular support member, forming the pleated porous member, and mounting the porous member in a position extending across the opening.

Abstract: A sealing gasket of foamed plastic is formed at the edge of a filter element of reticulated foam by placing the filter element on a surface adjacent to an open receptacle contoured as a mold for the desired shape of the gasket, filling the receptacle with a foam-forming liquid and avoiding contact between the liquid and the filter element until the liquid begins to froth. The liquid is then permitted to froth and overflow the receptacle on the side facing the filter element. As the froth contacts the filter element and proceeds to cure, it bonds to the edge of the elements without substantially penetrating its open pore network. The result upon curing is a gasket along the edge of a filter element fully bonded thereto without gaps or bypass, yet leaving substantially all of the surface area of the filter element exposed for use as a filter.

Abstract: An end-cap for a filter cartridge is formed by melting the thermoplastic material of a supporting cage and of a support pleated together with the filter medium against a heated die and embedding the end of the filter medium in the material while it is molten. Extra thermoplastic material may be melted in the die. If all of the components of the cartridge are thermolplastic, then they all fuse together and contribute to the end-cap.

Abstract: A method for preparation of macroporous polymeric membranes consisting in placing a mixture of monomers and a radical initiator, dissolved in a porogenic inert organic solvent selected from the group comprising alcohols, estes of carboxylic acids, ketones, and their mixtures, into a space of an adapted shape formed by two temperature-controlled plates and a distance insert having the thickness corresponding to the required thickness of membrane and heating up to 80.degree. C. for 24 hours at utmost in order to carry out the radical polymerization. Azo-bis-isobutyronitrile is advantageously used as an initiator in the amount 0.05-2 wt. % related to monomers in the polymerization mixture. Cyclohexanol or its mixture containing up to 20 vol. % dodecanol are advantageously used as a porogenic solvent in the amount 40-60 vol. % in the polymerization batch.

Abstract: In a sector-shaped screen segment for disk filters or thickeners with a folded screen for thickening fiber suspensions comprising a frame, two screen carriers and a screen resting on the outer sides of the screen carriers, manufacture is rendered simpler and less expensive by the frame and the screen carriers forming an integral molded part in which the screen is embedded in the molding process.

Abstract: A filter element includes unit members and spacers interposed one each between adjacent ones of the unit members. Each unit member includes a supporting plate having a pair of planar porous membranes joined to the opposite surfaces thereof and also having an opening for insertion of a spacer and removal of a cleaned fluid. The opening has an inner peripheral surface and a stepped part. Each spacer having an outer peripheral part and a stepped part. The stepped part of the opening of one unit member and the outer peripheral part of one spacer define a first axial seal part therebetween, and the inner peripheral surface of the opening of another unit member and the stepped part of the one spacer define a second axial seal part therebetween. The unit members and spacers are interconnected by tightly joining the supporting plates and the spacers at the first and second axial seal parts.

Abstract: A process for making a melt-blown nonwoven polymeric web for use as a liquid filter medium includes increasing the air (fluid) flow and the forming distance to produce a filter medium that is more bulky and more permeable and therefore resists plugging. The melt-blown process parameters include a polymer through-put between 1.8 and 2.9 PIH, a polymer melt temperature between 530.degree. and 600.degree. F., and air flow rate between 200 and 265 SCFM per square inch, air temperature between 500.degree. and 600.degree. F., forming distance between 12 and 23 inches, and a collector vacuum between 0.5 and 1.0 inch of water.

Abstract: A method of producing a filter for separating solid particles, whose diameters are generally smaller than 5 .mu.m, from flowing gases or liquids. A covering layer with columnar and/or platelet-shaped oxides is formed on a body consisting of porous steel foil at least in and around the pores.

Abstract: Composite membranes are disclosed having a separation layer comprised of a mixture of poly(methy methacrylate) or a copolymer thereof and at least one cellulosic derivative resulting in enhanced separation and permeating characteristics of the overall composite membrane. Processes for making these composite membranes and the methods of using them are also disclosed. The membranes are particularly useful in gas separation applications and are most suited for the separation of hydrogen from a hydrogen containing stream.

Abstract: A crosslinked composite membrane having high permeation velocity and sepaion factor and a process for producing the same. The membrane comprises a skin layer comprising a crosslinking reaction product of a water-soluble polysaccharide having a sulfonate group and/or a sulfonic acid group and a polyfunctional melamine compound the crosslinked composite membrane can be formed on a porous base such as an ultrafilter.

Abstract: A cell-type filter cartridge is disclosed having netting thereon, as well as a method for producing same. Briefly stated, the surface area of filter material exposed to unfiltered fluid has disposed thereon a netting thereby preventing flaking, cracking and the like of filter media during backflow or cleaning operations. The netting is secured to the cell by a molded circumferential retainer and a circumferential centrally disposed ring.

Abstract: A unitary injection molded filter is disclosed which includes a rigid frame of resin material to provide a rigid shape to the filter, and at least one screen of non-woven sheet resin material suspended on the frame and having formed therethrough a plurality of holes extending between the opposed side surfaces of the screen so as to form fluid passages therethrough. Each screen is integrally molded simultaneously with the frame.

Abstract: A process for producing a filter including a microporous membrane and a supporting structure connected thereto, including producing a mold for the membrane and the supporting structure, filling the mold with a molding material whose solubility can be changed by high energy radiation, and forming the micropores by partial irradiation of the membrane with high energy radiation and removal of the regions having increased solubility. The filter produced according to the above method is a unitary structure with the supporting structure integrally connected to the membrane.

Abstract: A method for manufacturing a microporous plate, a filter plate obtained from the method, and suction drier apparatus utilizing such filter plates. According to the method, a casting mix is introduced into the interior of a gypsum mold whereupon water is absorbed from the casting mix into the gypsum so that a crust remains on the inner surface of the mold. The crust is allowed to develop to an appropriate thickness whereupon the remaining casting mix is drained from the mold. The inner surfaces of the crust are allowed to dry whereupon the interior space defined between opposed crust wall portions is filled with a granular material which preferably has the same composition as the crust material. A filter plate comprises a pair of opposed suction walls defining an interior space between them which is filled with a granular material. The suction drier apparatus includes at least one of the filter plates which is mounted to be moved into and out of a basin or the like in which material to be dewatered is present.

Abstract: A tubular filter element for liquid filters comprises a perforated support pipe. Disposed around the inside of the support pipe is a tubular filter layer which comprises a folded sheet of filter material. Within each end of the filter element a spring washer is disposed for biasing the end of the tubular filter layer outwardly against the inside of the support pipe. In this pre-biased state, the ends of the filter element are joined to disks by means of a hardenable casting material.

Abstract: A double shell filter including an inner shell of bounded 80 to 400 U.S. mesh screen carbon particles and an outer shell of bonded 20 to 80 mesh screen carbon particles wherein the inner and outer particles are bonded internally to each other and the two shells are bonded together preferably by an ultra high molecular weight polymer binder having a melt index of less than about 1 gram per ten minutes as determined by ASTM D1238 at 190 degrees C. and 15 kilograms load.

Abstract: An improved composite polyamide membrane and methods of making the membrane are described. This improved membrane is prepared using a cationic polymeric wetting agent in an aqueous solution containing a polyfunctional amine reactant which is interfacially polymerized with an acyl halide to form a thin film polyamide discriminating layer on a microporous support. Alternatively, the wetting agent can be applied directly to the substrate and the interfacial polymerization can occur on said treated substrate. The resulting membrane exhibits an unexpected combination of high water flux, high rejection of divalent anion salts, variable sodium chloride rejection and good caustic resistance at low operating pressures. In one embodiment of this invention, a porous substrate is first treated with an aqueous piperazine solution containing a copolymer of vinylbenzyl dimethyl sulfonium chloride and methacrylic acid and then the coated microporous support is contacted with trimesoyl chloride in an organic solvent.

Abstract: The method of preparing dried asymmetric cellulose acetate blend membranes through the use of at least one drying agent which is a hydrophobic organic compound, such as polysiloxanes, hydrocarbons, ethers, ketones, chlorohydrocarbons or nitrohydrocarbons. The membranes are dried from their aqueous state by direct evaporation of water. The resulting air dried membranes are suitable for the desalination of water by reverse osmosis, non-aqueous liquid separation, ultrafiltration, pervaporation, and for the separation of various gaseous mixtures into their constituent parts.

Abstract: An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane.

Abstract: An automatic transmission fluid filter is disclosed, comprised of a metal base member, a plastic cover member attached to the base member, enclosing a volume. Filtration material inside the volume is interposed between an inlet and outlet to the filter. A plastic overmold around the periphery of the union of the metal and plastic members hermetically seals the filter except at the inlet and outlet. In a preferred embodiment, the metal base member includes a flanged edge which is secured to a flanged edge of the cover member by the overmold. Slots through the flange of the base member allow plastic of the overmold to flow through, connecting together plastic on both sides of the flange. Also, the base member flange ends curled lip embedded in the plastic of the overmold. Edge sections of the filtration material extend to and between the union of the base and cover members over some sections of the edge of the filter.

Abstract: A supported microporous membrane comprising a composite of a microporous membrane and a synthetic thermoplastic web of microfibers secured to the membrane without the use of added adhesive components and having an ASTM D903 peel strength of at least about 2 grams per centimeter, the composite having a modulus of flexure at leasts 10 percent greater than that of the membrane, and the method of manufacturing such supported membranes by contacting thermplastic microfibers with the membrane while the microfibers are at an elevated temperature.

Abstract: A method of manufacturing an integral asymmetrical membrane for the separation of liquid or gaseous mixtures. A membrane-forming agent in the form of a polyetherimide is mixed with a solvent that is miscible with water. The resulting mixture is introduced into or accommodated in a geometrical form. The form is then brought into contact with a precipitating agent and is post-treated.

Abstract: There is provided a method of manufacturing cellulose membranes with pore radii less than 30.times.10.sup.-10 m, suitable for reverse osmosis applications. The method comprises dissolving a cellulosic material in a DMSO/PF solvent at a temperature about 125.degree. C. for about 90 min., cooling and casting the solution at room temperature, evaporating the solvent at a temperature of 140.degree.-180.degree. C. and gelling the resulting membrane in a protic solvent, e.g. ethanol or water.

Abstract: A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pressures of 50 psi can attain a magnesium sulfate rejection with a 0.2 percent aqueous solution of more than 90 percent with a water flux of more than 15 gallons per square foot per day.

Abstract: A separation membrane having cell sizes in the range of 0.1 to 10 microns, prepared by:mixing at least one linear alternating polymer of carbon monoxide and at least one ethylenically unsaturated hydrogen in a solvent forming a solution;casting said solution on a substance, andremoving at least a portion of said solvent.

Abstract: The present invention relates to a method of producing micropores having diameters of less than 20 nanometers in straight sides in silicon film. The silicon film produced by this process may be attached to a substrate material and used as a filter in molecular separation processes.

Abstract: The microfilter foil is made of an inorganic substance such as metal with opened pores. Each pore is formed with a channel which increases in cross-section from the crest so as to obviate clogging. The foil is produced by exposure of a photosensitive layer of paint or lacquer with the use of an interference pattern produced by monochromatic and coherent light. A skin of inorganic material is produced on the photosensitive layer and portions of the skin are thereafter removed from the coated teeth in order to produce the pores in the subsequently formed foil.

Abstract: A process for producing a filter with multiple folds from an aqueous fiber mixture that is applied to a porous form, in which a paper-like filter mat is produced on the form under the action of pressure, and it is carried out without mechanical deformation of the rough casting. This is achieved pursuant to the invention by the fact that the aqueous fiber mixture is deposited on the porous form having the contour of the filter, from loading chambers separate from one another, and the filter is built up of adjacent fold sections in layers on the form by separate introduction of the fiber mixture to the fold sections connected to one another.

Abstract: A fluid filter is formed by manufacturing an air laid batt containing randomly disposed structural fibers and a thermoplastic binder fiber. The interstices between the fibers are fixed by applying a latex resin to the batt, thereby fixing the pore sizes of the filtering media before the filtering media is molded. The filtering media is then molded into shape by using a plunger to tuck the media into an open cavity mold. The mold may be heated and pressure may be applied to the batt to mold the batt.