Abstract: Highly asymmetric polyethersulfone membranes prepared from a stable, clear, homogeneous solution or stable colloidal dispersion of polyethersulfone are described. The membranes have a porous skin possessing a high density of skin pores with an average diameter of from about 0.001 micron to about 20 microns. In addition, the membrane has a porous support with an asymmetric region of gradually increasing pore diameters so that the opposite face of the membrane has an average pore diameter that is from about 50 to about 10,000 times the diameter of the skin pores.

Abstract: A pleated, all poly(tetra-fluoro ethylene) filter element (20) incorporating a poly(tetra-fluoro ethylene) filter membrane (24) is shown and described. The membrane is supported by an all poly(tetra-fluoro ethylene) paper (26) and (28), which permits filtrate to pass through the paper and across the poly(tetrafluoro ethylene) membrane. A sandwich is formed by placing a layer of poly(tetra-fluoro ethylene) filter membrane (24) between the two layers of poly(tetra-fluoro ethylene) support paper, (26) and (28), and the sandwich is then pleated prior to assembly around a core (14) and between end caps (12) and (18), which are bonded to the poly(tetra-fluoro ethylene) paper and poly(tetrafluoro ethylene) filter membrane by a hot-melt process.

Abstract: Highly asymmetric polymeric membranes with large pores which yield bubble points in the range of 0.5 to 25 psid and superior flow characteristics. The membranes can be cast from both metastable dispersions and from homogenous casting formulations. The technique of synthesis involves exposure of the cast membrane to humid air to create large surface pores on the exposed side.

Abstract: Substantially constant tension is maintained on a melt-blown nonwoven fibrous sheet by mounting the sheet take-up roller for longitudinal movements relative so as to accommodate the increasing diameter of the sheet material being wound convolutely on the take-up roller. Sheet tension during production is thereby maintained substantially constant by virtue of a continual increase in the longitudinal distance (in relation to the machine direction) between the fiber collection mandrel and the take-up roll. Preferably, tension control is achieved by a pneumatic pressure-regulating system which includes at least one rotatable press roller which is longitudinally fixed in position relative to the collection mandrel and is in contact with the sheet material being wound around the take-up roll. The take-up roller is pneumatically advanced toward the press roller by the pneumatic actuation of at least one air cylinder.

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: Apparatus and methods are disclosed whereby elongate preformed thermoplastic elements are friction-welded coaxially in an end-to-end manner so that the core elements are joined integrally to one another. Most preferably, the elongate elements are perforated tubular elements formed of a thermoplastic material which are employed as core elements in the production of cylindrical melt-blown filter cartridges. As such, the integrally joined core elements can be rotated and traversed as a unit relative to a melt-blowing die during the continuous production of indefinite length cylindrical melt-blown filter cartridges.

Abstract: The apparatus is provided to make a melt blown fibrous medium and includes first and second melt blowing dies for respectively issuing first and second streams of melt blown fibers along first and second melt blown paths. The first and second streams are issued on a forming surface where the streams are collected to form a melt blown fibrous medium. A movable transfer surface is interposed between the first die and the forming surface in the first path so that the first stream of melt blown fibers impinges on the transfer surface in advance of the forming surface such that the first stream is transferred to and brought into contact with the second stream of melt blown fibers on the forming surface.

Abstract: Apparatus and methods are disclosed whereby elongate preformed thermoplastic elements are friction-welded coaxially in an end-to-end manner so that the core elements are joined integrally to one another. Most preferably, the elongate elements are perforated tubular elements formed of a thermoplastic material which are employed as core elements in the production of cylindrical melt-blown filter cartridges. As such, the integrally joined core elements can be rotated and traversed as a unit relative to a melt-blowing die during the continuous production of indefinite length cylindrical melt-blown filter cartridges.

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: Apparatus and methods are disclosed whereby elongate preformed thermoplastic elements are friction-welded coaxially in an end-to-end manner so that the core elements are joined integrally to one another. Most preferably, the elongate elements are perforated tubular elements formed of a thermoplastic material which are employed as core elements in the production of cylindrical melt-blown filter cartridges. As such, the integrally joined core elements can be rotated and traversed as a unit relative to a melt-blowing die during the continuous production of indefinite length cylindrical melt-blown filter cartridges.

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 apparatus and method is disclosed for an improved fiber tow having plural diameter metallic wires, comprising the drawing of a first cladded metallic wire to provide a first drawn cladding of reduced diameter. The first cladding is separated into a primary portion and a secondary portion with the secondary portion being drawn to reduce further the diameter. A selected mixture of the primary and the secondary portions are cladded to provide a secondary cladding. A plurality of the second drawn claddings is cladded and drawn to provide a third cladding of reduced diameter. The third cladding is drawn and the claddings are removed to provide a fiber tow comprising metallic wires having a major diameter and a minor diameter. The fiber tow may be severed into uniform length to provide slivers of metallic wires having plural diameters.

Abstract: In critical filtration applications, filter cartridges are employed to replace ion exchange resin precoat filters to minimize the waste produced. The filter cartridges are backwashed with all gas and the liquid in the filter housing provides an active scouring effect as a result of the high levels of turbulence produced. The liquid, with entrained debris from the filter is minimized in volume.

Abstract: A precoat septum in the form of a winding onto a core of textured yarn produced of continuous filaments of an organic or inorganic material. The yarn is texturized by air blowing a plurality of said filaments utilizing an air jet, and drawing off the filaments at a speed which is lower than the speed at which they enter the jet so that the resulting yarn is characterized by the filaments having a plurality of random entangled loops.

Abstract: Cut resistant, abrasion resistant and electrically conductive yarns (1) are formed in torque-free form from stainless steel and other metallic yarns (2) served with or formed into composite twists with non-metallic yarns and fibers (4) and (5). The metallic yarn (2) is made up of at least about 60 ends, and up to as many as about 300 ends, of metal fibers (3) having a diameter of from about 2 to about 25 .mu.m. The absence of torque permits facile knitting into protective garments, such as cut resistant, abrasion resistant and/or electrically conductive gloves (10), or yarns which are as much as 85 to 90% by weight metallic fiber. When knit into gloves, added protection may be provided from puncture injuries if the palm (12), finger stalls (14) and thumb stall (16) are coated or impregnated with an elastomer or the like.

Abstract: Cut resistant, abrasion resistant and electrically conductive yarns (1) are formed in torque-free form from stainless steel and other metallic yarns (2) served with or formed into composite twists with non-metallic yarns and fibers (4) and (5). The metallic yarn (2) is made up of at least about 60 ends, and up to as many as about 300 ends, of metal fibers (3) having a diameter of from about 2 to about 25 .mu.m. The absence of torque permits facile knitting into protective garments, such as cut resistant, abrasion resistant and/or electrically conductive gloves (10), or yarns which are as much as 85 to 90% by weight metallic fiber. When knit into gloves, added protection may be provided from puncture injuries if the palm (12), finger stalls (14) and thumb stall (16) are coated or impregnated with an elastomer or the like.

Abstract: A continuous, self-cleaning, rotary filtering apparatus is provided having a plurality of filter elements within a rotatable filter housing adapted for rotation between an inlet plate having an inlet manifold and an outlet plate having an outlet manifold so that the liquid to be filtered is passed from the inlet manifold through the filter elements and into the outlet manifold. The apparatus is further provided with a backflushing capability whereby the filter housing can be rotated to position where one filter element in alignment with a backflush port independent of the inlet manifold so that a part of the liquid within the outlet manifold will be caused to flow backward through that filter element and backflush port to purge contaminants from the apparatus via the backflush port without interrupting liquid flow through the other filter elements. After backflushing, the filter housing is further rotated to return the backflushed filter element to service.

Abstract: Ultraporous and microporous polymer membranes cast from metastable dispersions are significantly improved by limiting the time of environmental exposure to less than about 0.5, preferably less than 0.25 seconds, between casting and quenching, and reducing the casting temperatures about 10.degree. to about 20.degree. C. lower than the usual prior art values. The resulting membranes have far less debris entrained in the membrane, far more consistent and uniform pore sizes, a substantially greater number of skin pores, and greatly increased flow rates for any given pore diameter. The membranes are highly asymmetrical and skinned with a standard deviation in flow rate of less than about 400 and a flow rate covariance of less than about 6, with skin pore diameters of from about 0.001 .mu..

Abstract: Ultraporous and microporous polymer membranes cast from metastable dispersions are significantly improved by limiting the time of environmental exposure to less than about 0.5, preferably less than 0.25 seconds, between casting about 10.degree. to about 20.degree. C. lower than the usual prior art values. The resulting membranes have far less debris entrained in the membrane, far more consistent and uniform pore sizes, a substantially greater number of skin pores, and greatly increased flow rates for any given pore diameter.

Abstract: Mono-layer thin film membranes are provided which are ultraporous. Such mono-layers are formed having a thickness on the order of about 1.2 to 150 nanometers, by a variety of polymerization, cross-linking, and film treatment processes to achieve the development of controlled pore sizes in the ultraporous size range corresponding to molecular weight cutoff values of from 500 to about 1,000,000. Such thin film mono-layer membranes are ordinarily supported on a microporous support material, desirably a microporous polymer membrane having a smooth, microporous skin with pore sizes in the range of from about 0.1 microns to about 3 microns, preferably from about 0.1 microns to about 0.5 microns, in diameter. There may be an intermediate gel layer. These membranes are useful for ultraporous, dialysis, and molecular separations.