Abstract: A method for preparing by solvent phase inversion spinning a hollow fiber membrane suitable for dialysis. The membrane includes at least one hydrophobic polymer and at least one hydrophilic polymer. An outer surface of the membrane is characterized by pores having sizes in the range of 0.5-3 ?m, with the density of the pores on the outer surface of the membrane being in the range of 10,000 to 150,000 pores per mm2. The method includes dissolving the at least one hydrophobic polymer and the at least one hydrophilic polymer in at least one solvent to form a polymer solution, extruding the thus-formed polymer solution through an outer ring slit of a nozzle with two concentric openings, extruding a center fluid through the inner opening of the nozzle, and wishing said membrane. The polymer solution coming out through the outer slit opening on the outside of the precipitating fiber is exposed to a humid steam/air mixture including a solvent content of between 0.5 and 10% by weight related to the water content.

Abstract: A porous membrane with the membrane wall constructed of a hydrophobic polymer and a hydrophilic polymer, wherein when the membrane wall is divided into 3 sections in the film thickness direction to form region “a” containing one wall surface A of the membrane wall, region “c” containing the other wall surface C and region “b” between region “a” and region “c”, the hydrophilic polymer content ratio Ca in region “a” is greater than the hydrophilic polymer content ratio Cc in region “c”, and the mean pore size of the wall surface C is larger than the mean pore size of the wall surface A.

Abstract: The present invention provides a method for the production of a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) asymmetric hollow fiber membrane. The invention comprises preparing a dope solution of PVDF-HFP with an additive of lithium chloride or glycerol dissolved in a solvent such as N-methylpyrollidone (NMP). The dope solution is spun to form a PVDF-HFP asymmetric hollow fiber membrane.

Abstract: Use of thermoplastic molding compositions comprising A) from 10 to 89% by weight of a polyethylene terephthalate which can comprise up to 65% by weight, based on 100% by weight of A), of another polyester, B) from 0.01 to 50% by weight of B1) at least one highly branched or hyperbranched polycarbonate with an OH number of from 1 to 600 mg KOH/g of polycarbonate (to DIN 53240, part 2), or B2) at least one highly branched or hyperbranched polyester of AxBy type, where x is at least 1.1 and y is at least 2.1, or a mixture of these, C) from 10 to 60% by weight of a fibrous or particulate filler, and D) from 0 to 20% by weight of further additives, where the total of the percentages by weight of components A) to D) is 100%, for the production of moldings by means of the internal-gas-pressure process and/or the water-injection process.

Abstract: A wrap film having very stable physical properties wherein a sock liquid maintains the lubricating effect as an opening agent while a sock is stabilized and parison width changes and meandering are reduced to eliminate parison wrinkles is provided. Specifically, the wrap film is a wrap film made of a polyvinylidene chloride-based resin prepared by melt-extruding a polyvinylidene chloride-based resin from a die in tubular form, cooling the outer side of the extrudate by using a coolant while an aqueous solution of a liquid that is compatible with water and forms one-component is retained in the hollow portion of the extrudate, and inflating the solidified extrudate, wherein the liquid that is compatible with water and forms one-component has a concentration of 80 to 95% by mass in the aqueous solution, and the liquid is applied to the wrap film in amounts of 50 to 4,000 ppm.

Abstract: A process for manufacturing of an asymmetric hollow fiber membrane, comprising the steps of extruding a polymer solution through the outer ring slit of a hollow fiber spinning nozzle, simultaneously extruding a center fluid through the inner bore of the hollow fiber spinning nozzle, into a precipitation bath, whereby the polymer solution contains 10 to 26 wt-% of polysulfone (PSU), polyethersulfone (PES) or polyarylethersulfone (PAES), 8 to 15 wt-% polyvinylpyrrolidone (PVP), 55 to 75 wt-% N-alkyl-2-pyrrolidone (NAP) and 3 to 9 wt-% water the centre fluid contains 70 to 90 wt-% N-alkyl-2-pyrrolidone (NAP) and 10 to 30 wt-% water, and the precipitation bath contains 0 to 20 wt-% N-alkyl-2-pyrrolidone (NAP) and 80 to 100 wt-% water.

Abstract: Strips containers are formed using two continuous webs in thermoformable and heat-sealable material facing each other. The webs are indexed along a feed line through different operating stations that transform the webs into a continuous strip of containers, each one of which is provided with a mouth. The containers are arranged according to two parallel rows that are opposed to a longitudinal median zone. The mouths of the containers of the upper row are arranged on the upper longitudinal edge of the strip and face upwards, whilst the mouths of the containers of the lower row are arranged on the lower longitudinal edge and face downwards. The method enables productivity to be increased and waste to be reduced.

Abstract: The invention provides a spinnerette assembly for forming hollow fibers. The spinnerette assembly contains an extrusion orifice and a fiber-forming material passage in communication with the extrusion orifice. A hollow needle extends through the extrusion orifice in a concentric manner to define an annular passage surrounding the needle. The fiber-forming material passage includes a fiber-forming material inlet port extending from a surface of the spinnerette assembly to an interior of the assembly and a transverse passage extending from the fiber-forming material port to the annular passage surrounding the needle. A bore forming fluid passage communicates with the interior of the needle.

Abstract: A wrap film having very stable physical properties wherein a sock liquid maintains the lubricating effect as an opening agent while a sock is stabilized and parison width changes and meandering are reduced to eliminate parison wrinkles is provided. Specifically, the wrap film is a wrap film made of a polyvinylidene chloride-based resin prepared by melt-extruding a polyvinylidene chloride-based resin from a die in tubular form, cooling the outer side of the extrudate by using a coolant while an aqueous solution of a liquid that is compatible with water and forms one-component is retained in the hollow portion of the extrudate, and inflating the solidified extrudate, wherein the liquid that is compatible with water and forms one-component has a concentration of 80 to 95% by mass in the aqueous solution, and the liquid is applied to the wrap film in amounts of 50 to 4,000 ppm.

Abstract: A method of producing a hollow fiber membrane includes discharging a polyvinylidene fluoride solution comprising a polyvinylidene fluoride resin and a poor solvent at a temperature above a phase separation temperature into a cooling bath at a temperature below the phase separation temperature to coagulate the polyvinylidene fluoride resin. The hollow fiber membrane comprises a polyvinylidene fluoride resin having spherical structures that have an average diameter in the range of 0.3 to 30 ?m.

Abstract: The invention relates to a method of manufacturing a tubular member made of synthetic material, the method being of the type in which the tubular member is extruded. In the method, during extrusion of the tubular member, the extruded synthetic material is subjected to a flow of water in liquid or steam form that comes into contact with the inside or the outside surface of the tubular member in such a manner as to form crevices in the surface of the tubular member that comes into contact with the flow of water. The extruded synthetic material is preferably subjected to a flow of water in liquid form. The surface including the crevices forms a low-friction surface. Application to making optical fiber cable networks in which the cables are inserted into tubes by carrying or blowing methods.

Abstract: A method of producing a hollow fiber membrane includes discharging a polyvinylidene fluoride solution comprising a polyvinylidene fluoride resin and a poor solvent at a temperature above a phase separation temperature into a cooling bath at a temperature below the phase separation temperature to coagulate the polyvinylidene fluoride resin. The hollow fiber membrane comprises a polyvinylidene fluoride resin having spherical structures that have an average diameter in the range of 0.3 to 30 &mgr;m.

Abstract: A hollow fibre membrane has an active layer (2) in which elongate polymer molecules (3) are longitudinally aligned essentially parallel to the extrusion direction to thereby define a plurality of spaced free volume cavities (4) which are particularly numerous and are essentially regularly spaced to provide enhanced selectivity when used in gas separation. The hollow fibre membrane is manufactured using a dry/wet phase separation process by spinning a dope composition which is extruded through a spinneret (12) having an annulus or annular orifice (16) together with a bore-forming fluid or coagulant. The dope composition has a power law index of less than 1 (unity) and the bore coagulant has a water activity of less than 1 (unity).

Abstract: The invention relates to a method of manufacturing a tubular member made of synthetic material, the method being of the type in which the tubular member is extruded. In the method, during extrusion of the tubular member, the extruded synthetic material is subjected to a flow of water in liquid or steam form that comes into contact with the inside or the outside surface of the tubular member in such a manner as to form crevices in the surface of the tubular member that comes into contact with the flow of water. The extruded synthetic material is preferably subjected to a flow of water in liquid form. The surface including the crevices forms a low-friction surface. Application to making optical fiber cable networks in which the cables are inserted into tubes by carrying or blowing methods.

Abstract: Apparatus and method for producing a hollow plastic section by extrusion through a die in a horizontal direction. The die has an inner mandrel which forms the cavity in the section. A first sealing plug and a second sealing plug, which sealing plugs are situated at a distance from one another downstream of the inner mandrel are attached to the inner mandrel. The sealing plugs are designed, during operation of the apparatus, to lie in the hollow section, such that they are sealed against the section, so that the sealing plugs and the section delimit a compartment in the cavity of the section. The compartment is filled with a liquid during operation of the apparatus. Vent means are located in the compartment for receiving and discharging gases or vapor which collects at the highest point of the compartment.

Abstract: Method for treating an extruded plastic section having a hollow space and installation suitable for carrying out such a treatment. The installation includes an extruder which has a core for forming the hollow space in the section and, at a distance downstream from the extruder in the extrusion direction of the section, a closing means having a rigid circumferential wall. The installation also has a first conduit connected to a supply orifice which is provided in the circumferential wall of the closing means, a fluid feeder connected to the first conduit and a second conduit connected to a discharge orifice. The discharge orifice is upstream of the supply orifice to provide a fluid film flowing opposite to the extrusion direction between the circumferential wall of the closing means and the extruded section.

Abstract: The process according to the invention for producing large-bore thick-walled pipes made of polyethylene comprises extruding the polymer composition out of an annular die 3 and subsequently cooling the melt 7 emerging from the die 3 using water as the coolant from the outside, the melt 7 emerging from the die being additionally also cooled with water from the inside. In order to ensure the internal cooling, according to the invention floating plugs 11 and 12 are inserted, which plugs are fixed in their physical position relative to the extrusion die 3 by means of retaining elements.

Abstract: A process for producing a hollow fiber membrane, a hollow fiber membrane, and a dialyzer of hollow fiber membrane type is provided. The hollow fiber membrane is highly biocompatible, and the production process is quite simple and inexpensive. In the process of the invention, the hollow fiber membrane is produced in a system wherein a polymer-containing spinning solution is extruded from a tube-in-tube type orifice of a spinner in a coagulation solution to form the hollow fiber membrane. The polymer-containing spinning solution is extruded from the outer tube of the orifice to form a cylindrical filament having an inner bore and a core solution is ejected from the inner tube of the orifice into the inner bore of the filament for coagulation of the filament. The filament is directly extruded into the coagulation solution or extruded into air and then drawn to the coagulation solution.

Abstract: A method for forming a hollow fiber bundle unit for insertion into an assisted breathing device comprising spinning a hollow fiber or hollow fibers, collecting multiple fibers into a bundle, filling the walls of the hollow fibers within the hollow fiber bundle with an humectant, coating the hollow fibers containing the humectant with a solution of an adhesive material, forming and drying the hollow fiber bundle coated with the solution, and preparing the hollow fiber bundle coated with the solution for insertion into the assisted breathing device.

Abstract: The present invention relates to a method for the production of a fiber-reinforced cellulose tube by continuous coating of a fibrous non-woven fabric with an alkaline viscose solution which is neutralized by means of an acid-containing precipitating liquid and is converted into regenerated cellulose, wherein on the path between viscose coating and immersion in the precipitating bath, aqueous, acid-containing precipitating agents are caused to act upon the fresh viscose tube within the tube for the purpose of stiffening and regeneration to form regenerated cellulose, the process being begun with the application of the precipitating liquid directly after conclusion of the embedding of fiber in viscose and the precipitating liquid being guided together with the tube with the aid of optionally fixed internal devices which are designed in such a way that they support the tube that has had precipitating bath applied to it and in the process maintain it in rounded shape, that the length of the inner preliminary prec

Abstract: A method and an apparatus for processing food into a tubular shape is provided in which a die for processing the food includes a guide plate having a material outlet and a cylindrical feed pin having a water outlet at its center co-axially housed in the material outlet. The guide plate and feed pin cooperatively define a ring-like opening. Food material is extruded out of the ring-like opening in a tubular shape. Simultaneously, hot water is expelled out of the water outlet of the feed pin, flows into and fills a hollow inside the tubular food material. The hot water in the hollow prevents the wall of the tubular food material from collapsing and also accelerates coagulation of the food material. Food material is thus continuously processed into a tubular shape. An extruding die for performing the described method is also provided.

Abstract: The present invention relates to a flexible tubular conduit with a jacket or tube made of crosslinked polyethylene, specially crosslinked polyethylene, and a method for manufacturing the conduit. A jacket or tube is made from polyethylene crosslinked by hydrolysis.

Abstract: A method for manufacturing plastic pipe such that the pipe has apertures formed therein when the pipe is viewed in cross-section, comprising the steps of having hot plastic flow through a die and subsequently be extruded through a die head to form an extruded wall component having first and second end wails, with the die head having formed therein a plurality of first sized gaps and a plurality of second sized gaps, with the second sized gaps having an aperture located inside each of said second sized gaps. The die is secured to a manifold assembly, with the manifold assembly comprising sets of tubes located centrally of one another, each set of tubes comprising a water inlet tube, a tube through which a vacuum is pulled, and a water return tube. Each set of tubes is positioned longitudinally within a respective die manifold tube with the outermost surface of each set of tubes spaced a first distance from the respective die manifold tube. Each of the respective die manifold tubes extends through the die.

Abstract: A method of making a porous polymeric material by heating a mixture comprising polyvinylidene fluoride and a solvent system initially comprising a first component that is a latent solvent for polyvinylidene fluoride and a second component that is a non-solvent for polyvinylidene fluoride wherein, at elevated temperature, polyvinylidene fluoride dissolves in the solvent system to provide an optically clear solution. The solution is then rapidly cooled so that non-equilibrium liquid-liquid phase separation takes place to form a continuous polymer rich phase and a continuous polymer lean phase with the two phases being intermingled in the form of bicontinuous matrix of large interfacial area, and cooling is continued until the polymer rich phase solidifies. The polymer lean phase is removed from the solid polymeric material.

Abstract: Extrusion of hollow membranes is improved by coextruding a coating fluid layer about the extrudate of heated polymer solution with its interior lumen forming extrudate. The coating fluid is disposed between the forming hollow fiber and a cooling fluid, and controls the rate of heat transfer to afford superior control over the structure and form of the hollow fiber produced in the invention. The coating fluid is typically the same material as the cooling fluid, and often is the same material as the solvent for the polymer in the heated polymer solution.

Abstract: The invention concerns a cooling plug for sizing the interior surface of thermoplastic extruded pipe. Vacuum and/or pneumatic pressure is applied at the surface of the plug. The pneumatic pressure may cause the inner wall to balloon outwardly to form bells within a mold or within an outer wall, to fit into corrugations of an outer corrugated tube, etc. The vacuum may be used to pull the inner wall back to the surface of the plug after application of pneumatic pressure.

Abstract: A method of making a porous polymeric material by heating a mixture of a thermoplastic polymer and a cationic or non-ionic surfactant having a hydrophilic-lipophilic balance range of 4.0 to 6.0 to a temperature and for a time sufficient for the polymer and surfactant to mutually dissolve. The mixture is then cooled to a temperature so that non-equilibrium liquid-liquid phase separation takes place to form a bi-continuous matrix of the polymer and surfactant so that the polymer and surfactant form two intermingled separate phases of large interfacial surface area. The surfactant is then removed from the polymer. The porous polymeric material produced by the above method has a lacey or filamentous structure consisting of a plurality of polymer strands connected together at spaced apart locations along each strand.

Abstract: A large-diameter plastic pipe is made by extruding from an extruding-nozzle assembly a hollow thermoplastic strip having an outer rectangular cross section and formed with longitudinally extending outer walls and webs having inner surfaces and defining a plurality of longitudinally extending internal cells separated by the webs from one another. Substantially only the inner surfaces of the outer walls and the cell-forming webs are then cooled to size the strip and provide it with a predetermined compressive strength stable up to a predetermined critical pressure of the design strength while externally shielding external surfaces of the strip and thereby preventing cooling of same.

Abstract: A process and apparatus for producing an elongated body changing in elastic modulus longitudinally thereof with use of polymers without resulting in variations in the outside and inside diameters of the body even when the polymers are different in extrusion characteristics or swelling characteristics. The apparatus may include a feeder 1 for extruding a first polymer in a molten state and a feeder 2 for extruding a second polymer, which is different from the first polymer in elastic modulus and similarly in a molten state. The feeders alternately discharge the respective polymers, which are continuously fed to a long-land die 5 along with a lubricant supplied from a lubricant applicator 4. The polymers are formed into the desired shape and cooled in the die 5, and thereafter extruded.

Abstract: A process of expanding plastics film is disclosed, together with an apparatus for performing that process, in which expansion of the plastics film is performed under the control of a liquid providing a stable hydraulic mass, by the downward extrusion and drawing of the plastics film, and the final expansion thereof, exclusively under the influence of the static and dynamic pressure of a hydraulic mass, at a position spaced downwardly of the extrusion head, the hydraulic mass being one that remains in a liquid phase at all temperatures encountered during the step of lateral stretching of the plastics film, to the exclusion of vaporization of the hydraulic mass.

Abstract: Asymmetric hollow fibers comprising a fluoropolymer, and a process for making such fibers. The hollow fibers are useful for making fluid separation membranes, especially gas separation membranes. In one embodiment of the process of this invention, a polymer dope having a viscosity of about 3000 poise or greater is prepared by solvating the polymer in a solvent system containing about 40%-90% N-methyl-2-pyrrolidone and about 60%-10% propionic acid by weight. The dope is dry-jet wet-spun into hollow fibers using a water-NMP core solvent. The fibers are coagulated in methanol. The fibers are then coated with a highly permeable material.

Abstract: In a tube eversion apparatus a first chamber in which the eversion pressure is developed is controllably sealed by a sphincter-type valve, the valve being in turn actuated by pressure developed in a preferably separately controllable and adjustable second chamber, another chamber preferably being provided above the sphincter-type valve for containing a supply of liquid and limiting turbulence from any escape of fluid past the sphincter-type valve, the other chamber also providing apparatus for supplying heated fluid to a lay-flat hose adapted to be pulled through the sphincter-type valve by the tube being exerted. Use of the improved apparatus involves appropriate modifications of the usual eversion process involving applying and controlling the everting pressure and the pressure exerted against the sphincter-type valve by the fluid in the second chamber.

Abstract: The process for production of polyacrylonitrile hollow threads with a stable, asymmetric pore structure by a dry-wet-spinning process with glycerine-based core liquids, definite draw and after treatment conditions and a treatment with alcohols and drying.

Abstract: As an article of manufacture, an ovenable shaped article formed of polyethylene terephthalate having a degree of crystallinity of at least 20%, said crystallinity being substantially uniform over the whole of the shaped article, and a process and apparatus for making same.

Abstract: A process for the preparation of a membrane comprising bisphenol-based polycabonate 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: A process is disclosed for the production of biaxially oriented liquid crystal films. The process includes:(i) forming an anisotropic dope from a polymerization solution of rigid rod heterocyclic liquid crystalline polymers such as poly{[benzo(1,2-d:4,5-d')bisthiazole-2,6-diyl] 1,4-phenylene}, its cis isomer or mixtures thereof, and poly{[benzo(1,2-d:4,5-d')bisoxazole-2,6-diyl] 1,4-phenylene}, its cis isomer or mixtures thereof, and a solvent such as polyphosphoric acid;(ii) extruding the dope to form a film;(iii) imparting biaxial orientation to the film to increase the transverse strength thereof;(iv) solidifying the biaxially oriented film; and(v) washing the solidified film to remove the solvent. Also disclosed is a liquid crystal film produced by the above process.

Abstract: A process for forming high free volume, asymmetric gas separation membranes having graded density skins and macrovoid-free morphology from a solvent system comprising a Lewis acid, Lewis base, and a Lewis acid:base complex which dissolve hydrophobic polymers. The dopes have high total solids, high viscosity and low coagulation (g) values which enhance rapid gelation without the formation of macrovoids and which minimize densification. The dope solvent system complexes are readily disassociated by the coagulation medium and the component molecules are miscible in the medium which provides for rapid desolvation of the formed membrane thus providing a membrane having low residual solvent retention.

Abstract: A microporous nylon hollow fiber is prepared by extruding a nylon spinning solution through an annular slit of an orifice into a quench liquid while simultaneously introducing a core liquid into the inside hollow portion of the extruded spinning solution where the weighted densities of the spinning solution, quench liquid and the core liquid are regulated such that the average of the density of the core liquid and the spinning solution is about equal to the density of the quench liquid.

Abstract: A process for preparing collagen tubes includes extruding an aqueous gel containing about 1.5% native collagen through a cylindrical spinneret equipped with a central concentric tube designed to receive a part of a coagulation bath, followed by coagulation of the internal and external walls of the tube, leaving the spinneret in a coagulation bath constituted by about 70% acetone and 30% ammonia, followed by drying. Following drying, the collagen tube may be subjected to reticulation by dehydration carried out at about 80.degree. C. under a pressure of about 0.1 mm of Hg (vacuum) for about 24 hours. The reticulated collagen tube may eventually be subjected to a treatment which permits the introduction of azide groups onto the molecule without requiring that the collagen be coupled to any external molecule.

Abstract: In a device for the extrusion of a tube the extruded tube (2) is guided by a piston (20) placed inside said tube (2) at a distance from the extrusion head (1) the cooling of the extruded tube (2) is improved by means of nozzles (13) which spray water (5) at an angle against the inside of the tube (2) and away from the extrusion head (1), the said water sprays further kept away from the extrusion head by a fan (17) which blows air through the tube (2) away from the head (1) means (14-22) being provided for the supply and discharge of water and air respectively.

Abstract: A skinless hollow fiber of a cellulose ester material is formed by providing an aqueous coagulation bath having a tube-in-ring jet immersed therein and extruding a spinning solution comprising at least one cellulose ester material and a solvent therefor directly into the bath through an annulus surrounding the tube of said tube-in-ring jet while simultaneously allowing a portion of the liquid in the bath to be autogenously aspirated through an opening in the tube, located below the surface of the liquid in the bath, and through the tube thereby forming a lumen in the extruded fiber and then drying the extruded fiber.

Abstract: A pipe plug apparatus and method for its use are described herein. A pipe plug is provided which includes a first portion, and second and third portions which radially extend from the exterior surface of the first portion so as to surround the first portion. When the plug is positioned in a pipe, liquid is introduced into the space as defined between the second and third portions, and as defined between the pipe interior surface and first portion exterior surface, so as to at least partially fill the space with the liquid.

Abstract: A method for the production of thermoplastic tubes comprising: (1) extruding the thermoplastic tube of which the interior surface in a molten state by a heating unit disposed within the area of a mandrel near the nozzle of an extrusion mold, and (2) sliding the interior surface of the tube on an additional mandrel supported to the front end of the mandrel through a heat-insulating material in axial alignment with the hollow mandrel in a manner to bring the interior surface of the tube into contact with the smooth surface of the additional mandrel and simultaneously cooling the interior surface of the tube with a cooling medium.

Abstract: A process for providing film tubes with anti-blocking means in that the film tube is cooled internally by an aqueous suspension containing a suspended release agent directly after extrusion, the excess suspensions are sucked from the interior and the tube, which is additionally cooled on the exterior in a water bath, is freed of remaining liquid by squeezing rollers.

Abstract: Equally biaxially oriented film is produced by extruding liquified polymer in tubular form, orienting the tubular film in the radial direction only and then either (1) equally orienting the radially oriented film in the longitudinal direction and drying the resultant equally biaxially oriented film while preventing any shrinkage thereof or (2) orienting the radially oriented film in the longitudinal direction to a degree less than said radial orientation but equal to the radial orientation remaining after the biaxially oriented film undergoes radial shrinkage upon drying thereof in the absence of radial shrinkage control and drying the resultant biaxially oriented film in the absence of radial shrinkage control.

Abstract: A method and apparatus for internal cooling of extruded tube-shaped objects wherein liquid nitrogen is inserted into the tube and evaporated there out of contact with the tube on account of the heat from the tube whereafter only evaporated nitrogen is made to pass through the inner surfaces of the extruded tube. The apparatus for evaporation of the liquid nitrogen and for conduction of the gasified nitrogen comprises a cylinder-shaped member with good thermal conductivity placed in the shaped tube adjacent to the extruder nozzle. Provided in the closed end of the cylindrical member are nozzle members with a connection to a supply line for liquid nitrogen inserted through the extruder nozzle. Provided in the opposite end of the cylindrical member are openings for passage of the evaporated nitrogen out towards the shaped tube.

Abstract: An improved method and apparatus for fabricating insulated cables, particularly polymeric insulated electrical power cables, resistant to the formation and growth of electrochemical trees is disclosed. Internal pressure on the conductor side of the cable is maintained lower than the external pressure on the outer surface of the insulation during extrusion. Extrusion pressure higher than the external pressure results in expansion of the insulation following extrusion. This expansion or swelling reduces the number and size of cracks and voids which are precursors of electrochemical trees. In addition, pressure curing the extruded, insulated cable with a curing medium above its melting point followed by gradual gradient cooling under internal pressure and higher external cooling fluid pressure to around room temperature optimizes the resistance of the cable to nucleation and growth of electrochemical trees.

Abstract: This relates to a die assembly for extruding tubular casing films wherein there are counter-rotating die members. One of the die members is mounted for shifting relative to its base under the influence of hydrodynamic pressures of the flowing extrudate so as to be self-centering relative to the other die member. This provides for a high shear cylindrical area leading into the die orifice which is of uniform thickness and which will provide for uniform fiber orientation due to the zero runout of the rotating dies.

Abstract: Long lengths of a heat-shrinkable sleeve for use in splicing electrical cables and the like are made in a continuous process. The sleeve is formed around a permeable core, and the core and sleeve are advanced together in an axial direction, the leading end of the advancing sleeve being hermetically sealed. The core and sleeve pass through a heating station, thereby heating a portion of at least the sleeve, and a fluid is introduced under pressure into the core, thereby internally pressurizing the sleeve to effect a radial expansion of the heated portion thereof. The core and sleeve then pass through a cooling station, thereby cooling the expanded sleeve to stabilize it. A stress graded compound also for use in splicing electrical cables and the like is made by heating a dimethyl silicone liquid to remove entrapped gas and mixing the liquid with a silicone carbide powder having a particle size capable of passing through a 400 mesh screen.

Abstract: In a tube eversion apparatus a first chamber in which the eversion pressure in developed is controllably sealed by a sphincter-type valve, the valve being in turn actuated by pressure developed in a preferably separately controllable and adjustable second chamber, another chamber preferably being provided above the sphincter-type valve for containing a supply of liquid and limiting turbulence from any escape of fluid past the sphincter-type valve, the other chamber also providing apparatus for supplying heated fluid to a lay-flat hose adapted to be pulled through the sphincter-type valve by the tube being .?.exerted.!. .Iadd.everted.Iaddend.. Use of the improved apparatus involves appropriate modifications of the usual eversion process involving applying and controlling the everting pressure and the pressure exerted against the sphincter-type valve by the fluid in the second chamber.