Abstract:
A hollow fiber membrane is made by covering a tubular supporting structure with a membrane dope and converting the membrane dope into a solid porous membrane wall. Optionally, a textile reinforcing structure in the form of a circular knit may be added around the supporting structure before it is covered in dope. The reinforcing structure thereby becomes embedded in the membrane wall. The supporting structure may be soluble in a non-solvent of the membrane wall, for example water, and may be removed from the membrane. Alternatively, the supporting structure may be porous. A porous supporting structure may be made by a non-woven textile process, a sintering process within an extrusion machine, or by extruding a polymer mixed with a second component. The second component may be a soluble solid or liquid, a super-critical gas, or a second polymer that does not react with the first polymer.
Abstract:
Material to be colored is fed from an extruder to a positive displacement means such as a gear pump. The output from which is split into at least two streams one of which is fed to a mixer which is preferably a cavity transfer mixer. Colorant is injected into one of the streams either before or at the mixer and the two streams are recombined downstream of the mixer preferably in a diehead. The arrangement provides for reliable coloration whilst premitting flexibility in production.
Abstract:
A method of and apparatus for simultaneously extruding a coating comprising a plurality of layers of dissimilar plastic compounds having substantially different melting points onto a moving electrical conductor wherein the plastic compounds are mechanically and thermally separated. Separating the two plastics prevents thermal degradation of the two extrudates by causing their melt temperatures to remain substantially constant.
Abstract:
In a method of producing an extruded, cross-linked cable coating of filled polyethylene wherein the extruder is charged with commingled polyethylene pellets and filler-EPR masterbatch pellets containing a peroxide cross-linking agent, the peroxide is incorporated in the masterbatch pellets by application to and absorption in the pellets during advance of the pellets to the extruder, while the pellets are continuously maintained at an elevated temperature for preventing bleed-out of absorbed peroxide.
Abstract:
Method for dispersing a fluid additive within only a portion of a stream of thermoplastic material comprising the steps of(a) flowing said stream of thermoplastic material into a channel having walls of substantially circular cross section, into which there has been placed a rotating mixer head having in the surface thereof a plurality of alternate lands and grooves each of said lands and grooves having an upstream end and a downstream end, said lands alternating with said grooves and being arranged in pairs, each of said pairs having a land in loose clearance with said wall followed by a land in close clearance with said wall, said mixer head having an unobstructed internal passage positioned therein over a substantial portion of its terminal length and a plurality of conduits severally connecting elongated zones between said lands pairs and said hollow internal passage, and(b) injecting said fluid additive into said channel at a position between said upstream and downstream ends of said lands and grooves.
Abstract:
A method of extruding a cross-linked material, more particularly an insulating cross-linked material around an electrical cable. In an extrusion machine comprising a housing terminated with an extrusion head and provided with a filtering means adjacent the outlet end of said housing, the cross-linkable product is fed without addition of a cross-linking agent, said cross-linking agent being first introduced in said cross-linkable material downstream said filtering means. The cross-linkable material is kept in the housing at an elevated temperature to be in a fluid state, the cross-linking agent being introduced at a temperature slightly lower than its reaction temperature, whereby the extrudate may be at a temperature near the maximum temperature admissible for the extrusion of said material.
Abstract:
In a process for forming a resin body, the thickness of the body is altered by altering the feed rate of raw material to an extruder and the screw rate of the extruder screw in such a relationship to alter the quantity extrusion rate without altering the amount of resin within the extruder.
Abstract:
A method and apparatus for extrusion of an article is provided. A die assembly can apply flows of thermoplastic material to an array of reinforcing cables to form a composite extrusion. A slider fabric can be bonded to one side of the composite extrusion. After exiting the die assembly, the slider fabric can act to support the extrudate as it passes along an elongate mandrel, which can cause the base of the slider fabric to change shape from a flat profile to the final internal profile of the article. The extruded article can then be cooled to solidify the material. The die can include cooling for the slider fabric and means for promoting penetration of the thermoplastic into reinforcing cables.
Abstract:
A tire rubber extruder automatic loading and management system is provided for continuous and automatic control of a rubber extrusion line. Batches of rubber slab material, whether for sidewall or tread, are connected in an automated manner to provide a continuous material stream for feeding a tread extruder supply conveyor within a tire manufacturing system. Joiner between adjacent slabs are implemented utilizing a stitched joint of material. Stitch pins are driven through both rubber slab layers to a specific depth into a clearance hole to create an optimized rubber mechanical adhesion zone. The result is a funnel shaped adhesion channel penetrating entirely through the layers of material perpendicular to the direction slab movement and tension. The resulting “rivet” like button structures are extremely strong, have no Impurities that could otherwise be added via adhesives, and can be formed in an automated manner within the available process cycle times.