Abstract: The invention is a process for the preparation of a POWADIR membrane comprising bisphenol-based polycarbonates wherein at least 25 percent by weight of the bisphenol moieties are tetrahalogenated wherein the halogen is Cl or Br, and the membrane prepared by such process.

Abstract: There is disclosed a process and apparatus for melt blowing at an initial velocity of from 500 to 1000 feet per second a molten thermoplastic condensation polymer at a temperature less than 50.degree. C. above the melting point thereof to form fibers of high molecular orientation, and collecting the fibers to form a non-woven web. In one aspect of the present invention, the fibers are collected on a rotating mandrel and heat treated during collection or subsequent to collection.

Abstract: Dewatering of sludge is accomplished by adding an organic fibrous material having the bulk specific gravity increased by being pressed or being wetted with water and a high molecular weight flocculant to the sludge, adjusting the resulting flocs to a diameter of not more than 1 mm, and subjecting the flocs to vacuum or pressure filtration.

Abstract: A cylindrical pressure vessel housing a filter media wherein the vessel is formed from a tubular thermoplastic pipe portion having opposite conical shaped end portions integrally formed with molded internal base portions with one base portion having integrally molded thereto the filter media in sealed position within the vessel housing.

Abstract: A fluid filter is formed by producing an air laid nonwoven batt comprising a randomly arranged mixture of thermoplastic fibers and fibers which are not thermoplastic. The batt is then cut into sections, and portions of the batt are heated to a temperature sufficient to partially fuse the fibers, thereby increasing the density of the portion of the batt which is heated. Accordingly, a gradient density filter may be produced having a progressively greater density from the fluid receiving side to the fluid expressing side, so that larger particles are trapped at the fluid receiving side and progressively smaller particles are trapped as the fluid flows through the media, with the finest particles being trapped at the fluid expressing side.

Abstract: Filter pads, which are made inherently stable by binders and by removal of the binders can be converted in packings to be maintained under substantially constant surface pressure between rigid filter brackets, are produced first as molded bodies from a suspension of filter aids in liquid by depositing granular, fibrous, or fiber-containing filter aids or mixtures of those filter aids in a casting mold, there being used high rates of flow while avoiding turbulences, and adding binders to the suspension so that the molded body can be stabilized by activation of the binder while drying. It is possible in this process also to manufacture multi-layered filter pads, it having been surprisingly found in those multi-layered filter pads that the layer assembly is kept intact during the filtration even in the filter packing that no longer contains binders.

Abstract: A filter element and method for making it include the steps of providing a pleated paper filtering media and providing a batt-like filtering media containing thermoplastic fibers which is slightly larger than the pleated paper filtering media. A ring-shaped die is used in a press to apply heat and pressure to the edges of the batt-like filtering media while accommodating the rest of the batt-like filtering media in the aperture of the die. Accordingly, a stiffened wall is provided which circumscribes the pleated paper filtering media. The pleated paper filtering media is attached to the stiffened, fluid-impermeable wall to provide a fluid-impermeable seal therebetween. A perimetrically-extending flange gasket is simultaneously formed around the edge of the batt-like media, so that the latter can be sealingly engaged in an air cleaner housing.

Abstract: A fluid filter and method for its manufacture in which an air laid batt is formed consisting of a randomly arrayed mixture of thermoplastic fibers and fibers which are not thermoplastic. The batt is cut into sections and is formed into cup-shaped articles in a heated mold. Accordingly, depending upon the degree of heat and pressure applied, the articles can be made of varying densities, to thereby provide articles of larger or smaller permeability and stiffness. The articles are then nested together to form a fluid filter in which fluid flows through the article of lowest density to remove the larger particles entrained in the fluid first, and then flows through articles of progressively higher density to remove progressively smaller particles. At least some of the particles have been heated and/or compressed sufficiently to be structurally self-supporting, thereby providing a filter article which does not need metallic centertube supports, etc., for structural rigidity.

Abstract: A filter suitable for press fitting into an assembly for inline filtration is disclosed. The filter includes a base, filtration material supported on the base, and a metal collar surrounding at least a portion of the base with a portion of the metal collar embedded in the base. The leading edge of the collar and anchor tabs on the distal end of the collar are embedded in the base and thus secure the collar to the base. The collar also has a rounded entry corner which provides a smooth entry into the press fit hole when the filter is pressed into place.

Abstract: The present invention relates to a continuous method for manufacturing an electret filter medium from dielectric material having an open or porous structure, said method comprising the steps of continuously feeding a web of dielectric material with a substantially closed dielectric foil adjacent to at least one major face thereof into a corona discharge device, reducing the thickness of the web of dielectric material and charging the web of reduced thickness dielectric material by means of a corona discharge and to apparatus for carrying out said method.

Abstract: A filter element comprising a hydrophilic organic polymeric microporous filter membrane having a preformed substantially non-porous sealing area and a filter housing having, preferably, a hydrophobic thermoplastic sealing surface in thermoplastic sealing relationship with the sealing area. Preferably, the filter membrane is a pleated cylindrical membrane and the housing includes endcaps thereto. The preferred membrane is nylon.The preferred pleated cylindrical membrane is produced from an elongated porous filtration area longitudinally bordered by substantially non-porous sealing areas. Such a membrane may be produced by a specific casting method or collapsing the pores along the longitudinal borders of the filtration area. The filter element is particularly useful for the filtration of aqueous liquids, particularly parenteral or body liquids.

Abstract: A filter device includes an annular filter element having a plurality of wave portions extending outwardly, a central cup-shaped portion arranged at an inner periphery of the filter element, a support frame arranged at an outer periphery of the filter element, and a connecting portion at which both sides of the filter element are abutting on and connected with each other. The central portion, the support frame and the connecting portion are made of synthetic resin and formed as a unitary structure, wherein the outermost and innermost peripheral ends of the filter element are respectively embedded in and held by the support frame and the central portion.

Abstract: Method for producing a separating nozzle element including a separating body and terminal plates, for the separation of a gaseous or vaporous mixture, wherein the separating body comprises separating structures which penetrate the separating body and define separating chambers and gas conduits, and the terminal plates are provided with channels for the intake and discharge of gas streams. A mold layer is produced which contains negative outlines of the separating structures. Thereafter, the negative outlines of the mold layer are filled with a structure material which is compatible with the gaseous or vaporous mixture to be separated to form the separating structures. The mold layer containing the negative outlines of the separating structure is produced by shaping the mold layer from a reusable tool provided with the positive outlines of the separating structures.

Abstract: The subject invention relates to methods and materials for making porous resin rigidified shaped articles suitable for filters, surgical trays, and the like, which comprises the steps of impregnating a non-woven fabric with a predetermined amount of thermoplastic or thermosetting water-based epoxy resin; partially curing the resin-impregnated fabric; and, thereafter molding the partially cured fabric into a desired shape with sufficient heat to advance the curing of the resin.

Abstract: An improved method and structure for sealing the ends of a tubular filter element is described. The method comprises providing a strip on non-porous film along the edge of a sheet of microporous filter material, the strip being joined to the filter material fluid-tight at its outer portion but forming a free flap on its inner portion, forming the element with the strip at one end and over the upstream side of the filter material, embedding the end in liquid sealer to a depth terminating over the flap portion of the strip, and solidifying the sealer. A similar procedure is described for seaming the axially-extending side edges of a cylindrical element.

Abstract: A method and apparatus for manufacturing plates of thermoplastic synthetic material or the like by compression molding is disclosed, wherein a mold comprising a respective, horizontally, disposed upper and lower part is first filled with synthetic base material in granular form or the like, is subsequently heated while being pressure-charged and closed for the purpose of melting the synthetic base material.

Abstract: An apparatus for, in one advantageous embodiment, concurrently forming a plurality of generally longitudinally extending grooves in a filter rod, and in another advantageous embodiment, for making small apertures in the grooves as the grooves are being formed in the filter rod. The apparatus includes a reciprocating die having an upper die block and a lower die block. Each die block includes protruding, elongated projections which are adapted to be imbedded into the filter rod upon closing of the die to impress grooves in the filter rod located in the die. In the embodiment wherein apertures are to be formed in the grooves, aperture forming punches are associated with each of the groove forming projections for punching apertures in the grooves as they are being formed.

Abstract: A cheese mold of polyolefin material having a non-woven inner layer of polyolefin fibers which is heat welded to the mold surface is disclosed. A method for manufacturing the mold is also provided. A non-woven layer of fibers is provided and a liquid mass of plastic is heat sealed thereto by extrusion or injection molding.

Abstract: An improved transmission fluid filter and a method of assembly wherein the filter comprises a plastic first member having a planar peripheral lip, and a sheet metal second member with a planar ledge and a continuous peripheral flange crimped over the cover lip and capturing the lip against the ledge. In accordance with the invention, a bead having an arcuate surface extends around the outside edge of the cover lip, and the flange is preformed in a continuous progressive bending or curling operation prior to engagement with the bead.

Abstract: Air filter elements employing a block of deep pleated paper and methods of their construction. A preferred filter element comprises top and bottom end members both adapted for through passage of air and a first pair of side walls, a block of deep-pleated paper between the end members and the side walls, connections between adjacent edges of the end members and the side walls, at least two connections being hinged and at least one connection being interengaging elements, sealing structure comprising a second pair of side walls and at least one flange around one end member, the material of which structure rigidifies the connections and forms a seal with the pleated paper. The sealing structure is formed preferably from an elastomer which solidifies in situ.In a preferred method of construction the first side walls are hinged up from the bottom wall around the pleated paper block and connected at the top. The second side walls and end flanges are then formed of elastomeric material.

Abstract: This invention provides a rotary heat regenerator which includes a regenerator wheel in which the regenerator matrix is formed of at least one strip of synthetic organic plastic wound onto a central hub, with suitable spacing means being formed in the strip to form gas passages. Inexpensive means is provided to stiffen the wheel to impart lateral strength and rotational stability. In one embodiment of the invention, radial portions of the face of the matrix are fastened together by fusing, by an adhesive, or both. In another embodiment of the invention, radial apertures are formed in the wheel by forcing a heated tool, radially into the wheel periphery so that the surfaces of the strip layers of the matrix are fused together, forming a hollow cylinder bounded by a continuous layer of plastic. To impart further rigidity to the wheel, the hollow cylinder may be filled with a reinforcing rod of plastic or metal.

Abstract: Ventilated thermoplastic polymer foam filter rods and the processes for their preparation. The ventilated thermoplastic polymer foam filter rods are characterized by the presence of at least some cells which are bridged by fibrils, the rod being surrounded by a high density skin structure having a discontinuity such as to produce a ventilation of at least 50%. Discontinuity in the skin structure may be produced by skin solvent etching, skin abraiding, skin perforating and skin cutting.

Abstract: Economical plastic well screens having good hydraulic performance can be produced by the method of the present invention wherein a sheet having a large plurality of V-shaped slots is injection molded, is roll-formed into a cylindrical shape, and then has its longitudinal edges bonded to each other. The resistance of the screen to collapse and tensile forces can be enhanced by the addition of ribs in one or two directions. Also, the sheet can be rolled in one direction or another to vary the slot direction or to permit flow from inside to outside as well as the conventional outside to inside.

Abstract: The invention relates to a support for a ceramic porous barrier of the kind used for obtaining a concentration of uranium 235 in uranium hexafluoride by ultrafiltration. The support is formed by superposing a number of layers in the form of pastes, the particle size being homogeneous and constant in each layer and decreasing from the outer towards the inner layers. The pastes are prepared from powdered materials such as metals, oxides, silicates, borides, nitrides and halides to which mineral binders are added. The pastes are simultaneously extruded or co-extruded after which the resulting support is baked.

Abstract: An improved method and structure for sealing the ends of a tubular filter element is described. The method comprises providing a strip of non-porous film along the edge of a sheet of microporous filter material, the strip being joined to the filter material fluid-tight at its outer portion but forming a free flap on its inner portion, forming the element with the strip at one end and over the upstream side of the filter material, embedding the end in liquid sealer to a depth terminating over the flap portion of the strip, and solidifying the sealer. A similar procedure is described for seaming the axially-extending side edges of a cyclindrical element.

Abstract: A replaceable filter cartridge has a pleated paper filter medium mounted within a frame or casing having a closed side and an open side, the open side being covered by a removable protective tray or lid the internal shape of which has been used in manufacture for moulding a sealing surface onto the periphery of the frame or casing, the closed side of the frame or casing being provided with a perforated portion which is also removable for use of the filter cartridge.

Abstract: A method is provided for making a filter cell comprised of two cellulosic fiber containing filter media having a sealed periphery. The method comprises compressing the peripheries of each filter media, to form a flange. The media are then aligned to provide intimate face-to-face contact between the flanges. A spacer means is provided between the media to cause each to dish outwardly from the other media. The two media and spacer means are then placed into a mold surrounding the flanges. The mold has a means for providing a recompression force to the inner portions of the flanges. A thermoplastic polymer is then injected into the mold to form a seal around the flanges. The recompression force is sufficient to maintain the flanges in intimate face-to-face contact with each other and to prevent seepage of the polymer between the flanges when the polymer is injected into the mold.

Abstract: A ceramic honeycomb filter consisting of a porous ceramic honeycomb structural body having a large number of channels extending therethrough, wherein given channels at one of the opening end surfaces of the honeycomb structural body have sealing portions formed by bending and bonding thin partition walls forming the opening end portion of the channels, and the remaining channels have sealing portions formed by bending and bonding thin partition walls forming another opening end portion of the channels, can be produced in a simple manner and is excellent in durability and mass-productivity.

Abstract: In the process of embossing film by continuously passing the film through a nip formed by cooperating pattern and backup rolls, the improvement of passing the embossed pattern while in registration with the pattern roll through a second nip to improve the pattern detail. The apparatus includes a second backup roll in pressurized contact with the pattern roll forming the second nip. The surface configuration of the rolls may be such as to locally perforate the film within the pattern.

Abstract: A method for forming a filter of electrically charged electret fiber material, consisting of a high molecular weight, nonpolar polymeric substance, comprising drawing, charging, and fibrillating a foil of said high molecular weight substance. The fibrillated foil is wound and then crimping is effected.

Abstract: A rigidized convoluted foam suitable as a self-standing filter is made by passing a sheet of air-permeable flexible polyurethane foam through a convoluting machine to obtain two unnested sheets of convoluted foam, each sheet being convoluted on only one side. The two sheets are nested and impregnated from the flat surface of each sheet almost to the closest valley surface with a thermosetting melamine, urea, or benzoguanamine resin in an amount to not appreciably impair the permeability of the foam and to increase the rigidity of the foam sufficiently so that each unnested sheet will be self-standing. After the resin has reacted, the nested sheets are separated.

Abstract: A self-supporting tubular filter including a sleeve of filter material and a frame formed by longitudinal and circumferential ribs attached to the sleeve. The filter is characterized by a longitudinal separation along a substantial length of the sleeve which is spliced together by one of the longitudinal ribs. That rib extends through the separation so that it overlies and is attached to the interior and exterior surfaces of the sleeve adjacent to the separation. Also disclosed are the use of the filter as a microemboli blood filter and a method of its manufacture employing a single male core pin with first and second female molds.

Abstract: A process for the manufacture of intravenous solution filter units includes injection molding a sealing member onto the periphery of the assembled filter components to hermetically seal the components into an integral assembly. The filter unit itself includes a housing and a filter element disposed internally thereof. The filter element is supported by a grid having a design and placement within the housing to assure, in conjunction with other structural features of the filter, the complete purging of gases from the filtrate. Also disclosed is a method for hermetically sealing the filter element to its thermoplastic support which provides an improved seal which will not leak. This method comprises the molding of the support, the alignment of the filter element on the support, the application of pressure to hold the element on the support and the overmolding of the periphery of the element to seal the edge of the element to the support.

Abstract: A process for producing a microporous sheet comprising peeling off a microporous sheet of a resin bonded to a plate from the plate in such a manner that the microporous sheet is split into two sheets.

Abstract: The embodiment of the invention disclosed herein is directed to a one-piece molded fluid filter and a mold construction for making the same. The mold construction is provided with first and second body portions having abutting surfaces forming a parting line. A plurality of axially spaced apart semicircular recesses are formed in the body portions to provide annular recesses in the mold. The parting line of the two body portions passes across the central area of each of the annular recesses. Longitudinal channels are formed in each of the body portions to provide a flow path for the injected resin. A core member having a plurality of axially and radially outwardly directed splines is inserted between the body portions and is dimensioned so that the splines come in direct contact with the lands between the recesses of the mold body portions.

Abstract: The invention provides a process for the continuous production of an elongate smoke filtering member comprising a heat-activatable bonding material and having air-permeable deformations at longitudinally displaced positions along its length, which comprises continuously advancing longitudinally a rod-like body of the material of the member, intermittently passing a hot fluid laterally into the advancing body to activate the bonding material substantially only at separate longitudinally displaced regions of the body, and deforming the outer surface of the advancing body at such regions where the bonding material is activated. Apparatus for performing the method comprises means for continuously longitudinally advancing the rod-like body, means for passing a hot fluid laterally into the body at regions longitudinally displaced along the body, and means for deforming the outer surface of the body at said regions.

Abstract: A method for the manufacture of an electrically charged fibrous filter from a highly molecular non-polar fiber material wherein a web of the fiber material is continuously fed and stretched. At least one side of the stretched web is homopolarly charged by a plurality of corona charging elements. The charged web material is then fibrillated, collected and processed into a filter.

Abstract: A method for the manufacture of an electrically charged fibrous filter from a highly molecular non-polar fiber material wherein a .[.web.]. .Iadd.film .Iaddend.of the fiber material is continuously fed and stretched. At least one side of the stretched .[.web.]. .Iadd.film .Iaddend.is homopolarly charged by a plurality of corona charging elements. The charged .[.web.]. .Iadd.film .Iaddend.material is then fibrillated, collected and processed into a filter.

Abstract: A method for forming a filter of electrically charged electret fiber material, consisting of a high molecular weight, nonpolar polymeric substance, comprising drawing, charging, and fibrillating a foil of said high molecular weight substance. The fibrillated foil is wound and then crimping is effected.