Abstract: A kneading apparatus includes a plurality of rotatable discs mounted on a screw shaft disposed on a hollow cylinder and a plurality of fixed doughnut members mounted on an inner wall of the hollow cylinder. The rotatable discs and fixed doughnut members are arranged alternately in an extending direction of the screw shaft. Projected portions and recessed portions extending radially and alternately arranged in a circumferential direction are formed on opposing side faces of the rotatable disc and fixed doughnut members in such a manner that the depths thereof are increased in proportion to the distance from a center of the screw shaft. Accordingly, the kneading apparatus is allowed to have a small construction and yet capable of efficiently kneading the material. In addition, material is prevented from remaining locally in the apparatus, and thereby a proper shear force is applied to the entire material.

Abstract: A plasticizing apparatus (10) including a barrel (12) having a bore (14) therethrough. An auger (24) and a rotor (30) are positioned in the bore, each extending from opposed ends (16, 18) of the barrel (12) and having ends (26, 34) that are substantially flush. The auger (24) conveys particulate plastic material along the bore (14), the plastic being frictionally melted before passing the auger discharge end (26). The rotor (30) is provided to uniformly heat the melted plastic. Auger (24) and rotor (30) each are associated with independent means for rotating (28, 32) and means for controlling the speed of rotation (50, 52). The speed of rotation of the auger (24) controls the flow rate of plastic through the bore, and the speed of rotation of the rotor (30) controls the temperature of the melted plastic.

Abstract: A machine for processing solid and viscous plastic materials includes a screw element having a shearing flight and a scraping flight. Upon rotation of the screw, the shearing flight shears the plastic material and the scraping flight guides the material to the shearing flight. Preferably, the screw includes a plurality of threads which extend from one end of the screw to the other, and which include a plurality of shearing and scraping flights.

Abstract: A feedscrew for an extruder or molding apparatus has an elongated body with a helical thread formed thereon defining a first channel "A ". At the start of a mixing section, a channel "B " is cut in the center of the channel "A " and both channels are of the same pitch. The channels start at the same depth, but the channel A decreases in depth to a minimum and the channel B increases in depth to a maximum. The channel B then decreases in depth to a minimum and the channel A increases in depth to a maximum where the channels are again at the same depth. This channel within a channel configuration is repeated along the mixing section. The purpose of the arrangement is to compress and decompress the material being fed through the assembly to obtain the desired mixing action for low shear homogenization of the viscous plastic polymer.

Abstract: An extrusion apparatus having a rotor member rotatable within a barrel member longitudinal and cross-sectionally mixes and extrudes thermo-plastic and thermo-setting materials. The apparatus is articulated into sections including a barrel entrance and forcing section, a blending section, and an end discharge section. The barrel entrance and forcing section consists of helical extrusion grooves which terminate at an abrupt rotor to barrel and barrel to rotor material transfers. The blending section recognizes that blending is volumetric i.e. three-dimensional and therefore longitudinal displacement of the material in relation to itself is one of the dimensions. Longitudinal displacement is accomplished in the blending section by providing a double extrusion capacity main extrusion rotor and a single capacity backfeed rotor arranged to recirculate half of the material processed by the main stream rotor.

Abstract: A polymer-extruder screw has a mixing section with relatively deep channels between flight lands at a proximal end, progressively shallower channels with a progressively larger screw core of a central transition section, and finally a metering section having a plurality of at least three pressure channels juxtaposed helically between flight lands having channel interruptions comprised of helical inclines and constant-radii tops in helical progression to a distal end of the extruder screw where the pressure channels end with equal depth at an interface with a metering gate of an extruder. The pressure channels can be symmetrical or asymmetrical in angles of incline and decline at opposite helical sides of the channel interruptions for optimizing channel depths, for positioning of maximum channel depths in relation to tops of channel interruptions, for equalizing channel depths at the distal end of the extruder screw and for optimizing incline and decline advantages for polymers with different characteristics.

Abstract: In a process for the manufacture of thick, preferably sheet-shaped, thermoplastic molded parts or molded parts having areas of variable cross sections, at least one part of the plastic material is conveyed as a melt into a heatable and optionally coolable compression mold and is subsequently compressed. Plastic granules are mixed in with the melt before the melt is conveyed into a compression mold. A device to prepare such mixture of melt and plastic granules includes a first section designed as a melt extruder and a subsequent section designed as a mixing extruder. The granules can be fed into the melt between both extruder sections or into the second section.

Abstract: A twin conical screw extruder which includes a twin conical container having a material inlet port, a material extruding port on the opposite side of the material inlet port, and an inner conical wall surface converging toward the material extruding port, a pair of conical screw rotors accommodated in the twin conical container, each of the conical screw rotors having a free end adjacent to the material extruding port and a base portion rotatably supported such that the screws of the two rotors intermeshingly rotated in two different directions and a pressurizing device provided in each free end of the screw rotors so as to forcibly keep the free ends of the screw rotors in contact with each other at a predetermined contact pressure so as to overcome a pressure arising from the extruding operation.

Abstract: A plasticating apparatus having a barrel and a screw rotatably disposed therein. The screw has a mixing section including a helical conveying flight to form a helical passage for transporting resinous material along the screw. The mixing section further includes two helical divider flights, each spaced from the conveying flight to divide the helical passage into three channels of varying cyclic depth in the helical direction of the channels. The portions of minimum depth of the channels define wave crests which are helically displaced from each other.

Abstract: An extrusion apparatus is provided for the mixing and extrusion of thermo-plastic and thermo-setting materials and the pelletizing of thermo-set materials, in which a rotor member is rotatable within a barrel member. The apparatus is articulated into three sections including a barrel entrance section, a forcing section and a metering section. Each section is provided with helical rotor extrusion grooves, and is followed by a circumferential barrier and a rotor to barrel to rotor mixing zone. The circumferential barrier is provided with a clearance, barrier top to barrel bore, designed to pass fluent material and retarding the over-size and less fluent material. The leading edge of the circumferential barrier is provided with multiple dual purpose plows which, direct the fluent material downstream and the over-size and less fluent material upstream for additional working.

Abstract: A mixing section for an extrusion or injection screw has alternating helical wiping and barrier lands which form inlet and outlet channels therebetween, with the barrier lands having a greater helix angle than the wiping lands, creating a conjunction of the adjoining wiping and barrier lands near the input and exit ends of the mixing section. The barrier lands also have notches cut therefrom to promote mixing and throughput. The barrier lands are widened at the conjunction with the wiping lands to form the termination of the downstream end of the inlet channels and the beginning of the upstream end of the outlet channels. Some or all of the channels do not have uniform depths such that the channels gently rise up to the narrowed beginning of the outlet channels and the narrowed ending of the inlet channels, with this tapering avoiding any pocket or hang-up area where melt flow could gather or degrade.

Abstract: Rotor zone cooling apparatus channels liquid coolant flow in rotors in continuous mixers of plastic materials for causing predetermined zones along the lengths of the rotors to be cooled as may be desired and for other predetermined zones to remain neutral, i.e. without significant cooling. A sequence of alternating cooling/neutral/cooling/neutral/cooling/neutral zones can be arranged, including zones of various possible length, various possible locations and various possible numbers of such zones. These zones are tailored or customized for optimizing temperature conditions along a rotor depending upon the mixing requirements and characteristics of plastic materials being mixed. Within an axial bore in a rotor is inserted a novel elongated cooling tubing assembly which rotates with the rotor. For creating a neutral zone, coolant flow is diverted inwardly into an isolation channel within an isolation tubing section spaced inwardly from the rotor bore wall.

Abstract: An extruder screw mixing head that is adapted to be carried by an extruder screw at a downstream portion of the screw for improved distributive mixing. The mixing head includes a central body that tapers and diverges in a downstream direction to provide a progressively diminishing flow channel in an axial direction of the mixing head. Four equally spaced flights of equal pitch are provided on the outer periphery of the mixing head, and each flight has a series of peripheral recesses that are spaced from each other along the flights and that permit flow of plasticated material between adjacent flow channels defined by the spaced flights to improve homogeneity of the material. The recesses are so configured that their respective leading and trailing edges are aligned to define circumferential angles with the longitudinal axis of the mixing head, so that the inter-channel flow areas of the recesses increase in a direction toward the outlet of the extruder barrel.

Abstract: A pin transfer extruder is provided, wherein the pin-barrel and transfer mixing sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. Throttle pins, which are disposed in the transfer mixing section in the region of the greatest housing thread volume, permit universal use of the extruder in respect of the extruded material. The combination of both mixing systems permits the throughput of material to be increased in a surprising manner by 60% to 100%, while a constant mixing quality is maintained and the driving torque is halved. The number of the housing and screw flights remains independent of the cross-sectional area of the housing and screw threads because the number of housing and screw threads is constant.

Abstract: A pin transfer extruder is provided, wherein the pin-barrel and transfer mixing sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. Throttle pins, which are disposed in the transfer mixing section in the region of the greatest housing thread volume, permit universal use of the extruder in respect of the extruded material. The combination of both mixing systems permits the throughput of material to be increased in a surprising manner by 60% to 100%, while a constant mixing quality is maintained and the driving torque is halved.

Abstract: A single-screw degassing extruder for thermoplastic plastics materials and rubber is provided, wherein the pin-barrel and transfer sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. Throttle pins, which are disposed in the transfer section in the region of the greatest housing thread volume, permit universal use of the extruder in respect of the extruded material or combinations of extruded material and stripping agent, since the mixing efficiency of the extruder and the pressure of the extruded material upstream of a degassing opening in the extruder are thereby advantageously controllable.

Abstract: A barrier screw having a feed zone, a compression zone and a metering zone, the screw including a shaft, a main flight provided on the shaft and a subflight provided on the shaft. The subflight is developed on the compression zone and then joins with a rear surface of the main flight prededing the subflight by one pitch at an end portion of the metering zone. The subflight defines a melt channel whsoe depth is substantially constant, so that the mixing function of the screw is improved.

Abstract: An extrusion apparatus is provided for the mixing and extrusion of thermo-plastic and thermo-setting materials and the pelletizing of thermo-set materials, in which a rotor member is rotatable within a barrel member. The apparatus is articulated into three sections including a barrel entrance section, a forcing section and a metering section. Each section is provided with helical rotor extrusion grooves, and is followed by a circumferential barrier and a rotor to barrel to rotor transfer zone. The circumferential barrier is provided with a clearance, barrier top to barrel bore, designed to pass fluent material and retarding the over-size and less fluent material. The leading edge of the circumferential barrier is provided with multiple dual purpose plows which, direct the fluent material down-stream and the over-size and less fluent material up-stream for additional working.

Abstract: A high-performance extruder is provided, wherein the pin-barrel and transfer mix mixing sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. The combination of both mixing systems permits the throughput of material to be increased in a surprising manner by 60% to 100%, while a constant mixing quality is maintained and the driving torque is halved.

Abstract: There is provided an injection molding apparatus of the screw in-line type which has a screw having the following structural features and is used for injection-molding a high-nitryl resin.(1) A compression ratio is set to a value of 1.8 to 2.5.(2) Ratios of the lengths of the feed section, the compression section, and the metering section are set to[1 to 1.5]:[1.8 to 2.8]:[1].(3) A depth T (unit:mm) of groove of the metering section in relation to an inner diameter D (unit:mm) of the cylinder is set toT.gtoreq.0.057D-0.2.(4) A radius of curvature R (unit:mm) of the arc surface of the rear side corner portion which is formed between a screw shaft and a flight in relation to the inner diameter D (unit:mm) of the cylinder is set toR.gtoreq.0.36D+2.0.

Abstract: An extruder with at least one bore, in which an extruder shaft is arranged to be rotatingly driven, has a device for introducing a glass fibre strand. To this effect the shaft is provided with an adjustable throttling device, upstream of which starts out an impregnating channel which opens again into the bore downstream of the throttling device seen in conveying direction, i.e. into a mixing zone, in which the fibre strand is cut into fibre sections. An especially intense impregnating of the fibres of the fibre strand is thus achieved.

Abstract: An extrusion machine includes a barrel or cylinder which houses an extrusion screw. The screw includes a feed section into which powder material is fed. The material is then fed into a mixing section, then through a transition section and then to another mixing section and finally to a section for mixing and metering the material as it is fed to the die. The extrusion screw in each of the mixing sections includes a double flight for causing the material to move back and forth in each section as it is fed to the discharge end of the barrel. The mix and meter section also includes keys to further mix the material.

Abstract: A plasticating apparatus and method for its use including a rotating screw having a helical flight disposed within and cooperating with the inner wall of a heated barrel with said barrel provided with inlet and outlet openings so that particles of resinous material are introduced through said inlet opening to a helical valley extending along said flight to be plasticated by said screw and advanced towards said outlet opening. A barrier extends along said helical valley to divide said helical valley into coextensive side by side helical valley sections. The barrier extends in a path which is non-parallel and alternating with respect to the helical flight so that the pitch of the barrier is alternately greater than and less than the pitch of the helical flight. The height of the barrier is less than the height of the flight so that the resinous material overflows the barrier due to changes in width of said side by side helical valley sections.

Abstract: Apparatus and method for use in a plasticating extruder of the type having an axially extending elongate barrel for preparing a plasticated material from solids introduced into the extruder wherein an axially extending screw conveyor continuously conveys material in a downstream direction as the material is melted within a channel in the screw conveyor, the channel extending between a leading face and a trailing face on a flight of the screw conveyor such that a solid bed of material is established and melting takes place to form melted material within a relatively thin melt film established between the solid bed and the barrel, the melted material passing progressively from the melt filn into a melt pool formed at the leading face of the flight, and melted material is transferred within a conduit in the screw conveyor from the melt pool to the solid bed, whereby the transferred melted material is forced into intimate contact with unmelted material in the solid bed to heat the unmelted material and accelerate

Abstract: A resin composition of a thermoplastic resin and long fiber is injected into a molded article having good physical properties by molding the composition in the form of a pellet having a length of 3 mm or more and containing 10 to 80% by weight, based on the composition, of a fiber having a length substantially equal to that of the pellet and arranged in the lengthwise direction of the pellet, characterized by using an injection molding machine having a nozzle diameter of 6 mm or more.

Abstract: A plasticating apparatus having a barrel and a screw rotatably disposed therein. The screw has a mixing section including a helical conveying flight to form a helical passage for transporting resinous material along the screw. The mixing section further includes a helical, zig-zag barrier flight spaced from the conveying flight to divide the helical passage into channels of varying cyclic depth in the helical direction of the channels. The portions of minimum depth of the channels define wave crests which are helically displaced from each other. The barrier flight has a first section converging toward one side of the conveying flight, and a second segment diverging away from the same side of the conveying flight. The plurality of first and second segments repeat throughout the mixing section.

Abstract: This invention relates to a rotary kneading screw installed in an extruder kneading and extrusion-molding a material mixture of a synthetic resin such as polyester resin mixed with one or more of master-batch, calcium carbonate, talc and carbon fiber. Progressively higher pressures are applied to the material mixture passing through a kneading section defined in the rotary screw. This rotary kneading screw is thus capable of kneading and extruding the material mixture in a large amount without deteriorating its physical properties and without lowering fluidity and molecular weight thereof even where the material mixture is difficult to knead.

Abstract: The extrusion screw for thermoplastic material comprises a helical thread, having a trapezoidal profile with a flat crest and inclined flanks, the pitch and the width or the root of which remains constant, while the inside diameter of the screw increases from the entry of the screw in the direction of the exit.

Abstract: In a method for processing granulate and/or pulverulent polymer with pulverulent additives in an injection moulding machine having a screw with a feed zone of constant screw core diameter, and intermediate zone with a compression and metering section and a mixing element array, with regard to particularly economic processing to high quality injection mouldings the polymer and the pulverulent additives are introduced without previous preparation directly into the feed zone of the screw and in the feed zone the polymer is thoroughly mixed with the pulverulent additives at least twice by means of mixing element arrays, the working length of the screw for the processing having at least 19 times the screw diameter.

Abstract: An extruder screw and a method for extrusion to achieve high output rates with thermally sensitive plastic materials and without thermal degradation problems involving the use of a single flight metering type extruder screw having an initial feed zone, distal metering zone, and a transition zone interconnecting the feed and metering zones. In particular, improvements in the extrusion of thermally sensitive plastics such as PVC are achieved through use of a compression ratio of approximately 2:1, a constant lead and pitch, and a proportioning of the length of the feed zone, transition zone, and metering zone relative to the total length of the zones of 27-33%, 23-25%, and 45-48%, respectively. To achieve cooler and more uniform mixing with rigid PVC, polyethylene and like materials, an improved arrangement for using rings of mixing pins is provided.

Abstract: An extruder for processing wood particles, shavings or sawdust is particularly useful for the production of a refined product exhibiting a large number of separated, individual fibers each of a relatively long length as is desirable in the production of a fiber core for a composite particle board. The extrusion apparatus comprises an elongated barrel and a flighted screw rotatable within the barrel, with the final downstream section of the screw being of a configuration to sequentially present three processing zones each having a compression region, a restricted region and a decompression region. The three processing zones of the final screw section cooperate with a compression region and restricted region formed in the final head section to choke the advancement of wood materials through the extruder sufficiently to enable satisfactory processing of the same without the use of a final die or restricted orifice disposed on the outlet of the extruder barrel.

Abstract: Ionomers can be injection molded and extruded in wet condition using a vented, two-stage barrier screw wherein the barrier flight melt channel is operated only partially filled.

Abstract: The apparatus is for the continuous mixing of rubber like polymers with chemical additives to form a homogeneous compound, using minimum unproductive work, such as mixing already mixed material, or massive batch blending to correct lean and rich mixtures previously produced. The apparatus consists of a feeding means adapted to continuously and uniformly advance baled polymer into a machine hopper provided with a multi-purpose rotor, adapted to cut the advancing bale into shreds, in the presence of the chemical additives, mix the shredded polymer with the chemical additives and advance the resulting compound into a continuous mixing means. Mixing with minimum waste motion is expected to produce a superior compound not possible to obtain with present day production equipment.

Abstract: A method of degassing thermoplastic plastic melts over a wide range of viscosities in a degassing extruder including a plurality of sequential degassing sections. Each degassing section includes at least one screw section having flights formed thereon. Each section includes a degassing region and a metering section downstream thereof. The height and length with which the flights are filled in the degassing regions in the individual degassing sections is controlled by the comparison of a pressure gradient measured in the metering region of that section with a desired pressure gradient and on the basis of this, the melt is conveyed with substantially the same throughput capacity in each degassing section. As a result of these measures, the degassing is effected in all of the degassing sections with optimally partially filled screw threads and with an optimum filling length of the worm threads, which is independent of the viscosity of the melt.

Abstract: An apparatus including a single screw extruder for extruding a fused molten mass of thermoplastic material and for reverse degassing the melt. The device includes an extrusion screw rotatable in a hollow cylindrial barrel, and a hopper for introducing the melt into the barrel. The screw has at least one flight for conveying the introduced melt and a return delivery flight disposed upstream, in the direction of extrusion, of the hopper. Reverse degassing of the melt is effected by a vacuum source disposed upstream of the hopper in communication with the return delivery section, and provided with a degassing dome generating a reduced pressure or vacuum. At least one radially adjustable separating member for effecting mechanical separation of fused mass from the gas is provided in at least one location in the return delivery section. The method includes degassing of the melt by producing a reduced pressure in the return delivery section. The gas extracted from the melt is discharged.

Abstract: This invention relates to a method and apparatus for melting and conveying plasticated materials by independently developing an initial melt film which is necessary for proper conveying of the material. The apparatus includes a barrel having a cylindrical bore therethrough, a shaft rotatable in said bore which has a substantially circular cross-section, the shaft and bore defining a feed section, a metering section and a transition section between the feed and metering sections. The shaft is provided with a helical first channel means integral with the shaft for conveying said plasticated material in a downstream direction through the feed section, the transition section, and the metering section when the shaft is rotated.

Abstract: A continuous granulator of the double-screw type includes a mechanism by which the degree of kneading can be controlled, and prevents lateral communication between the screw ends. A gear pump connected after the screw cylinders delivers the material to the cutting unit.

Abstract: A twin screw extruder which significantly reduces extruder wear through provision of separate, complemental, interfitted frustoconical screw and barrel sections adjacent the outlet end of the extruder barrel which create an even, bearing-type support for the rotating screws as material passes through the apparatus. In preferred forms, the screws are intermeshed along the majority of the extruder barrel, but diverge at the region of the final frustoconical screw sections and are received within respective complemental barrel sections; in this fashion the material being processed is split into juxtaposed, non-communicating streams, and thereby evenly flows around and supports the adjacent screw section to lessen the tendency of the screws to separate themselves and come into wearing contact with the surrounding barrel walls. The extruder can be used to process a wide variety of plant-derived materials, but is particularly useful for viscous substances (e.g.

Abstract: This invention relates to a process of producing sheets from thermoplastic resins and a screw used therefor. The resin extruder includes a cylinder and the screw. The resin is passed through a feeding section, a compressing section, a metering section, a mixing section, a shearing section and a stress relaxing section, which are successively positioned from a resin feeding side to a resin extruding side, and a molten film-shaped resin is extruded, and this film-shaped resin is passed in a co-current direction with cooling water and is cooled.

Abstract: The apparatus is for the straining and processing of plastic and rubber like materials and has a rotor rotatably mounted in the bore of a cylindrical barrel and operable to move process material, from one end of the bore to the other, to progressively heat, develop pressure, transport and separate the fine and fluent from the oversize and less fluent process material and to discharge the separated materials from different ports.

Abstract: This invention relates to a mixing device for a feed screw for melting and conveying plasticated material of the type which rotates about a longitudinal axis in a barrel of an apparatus for melting and conveying plasticated material. The feed screw includes consecutive feed, transition, and metering sections, and further includes at least one helical main channel for conveying material in a downstream direction. The mixing device includes a cylinder having a clearance from the inside of the barrel, which cylinder rotates with the feed screw about said axis within the barrel. The outer surface of the cylinder is provided with at least one continuous mixing channel which extends over the surface of the cylinder, the channel being disposed in alternate upstream and downstream directions wherein material conveyed in the mixing channel is caused to alternately reverse its direction while proceeding through the mixing channel.

Abstract: Extrusion machine and process, the machine having a barrel having a feed section for receiving solid extrusion material, and containing a screw for moving the solid extrusion material through a solids conveying section to a compression section of the barrel to generate heat and pressure to melt the extrusion material and force the melt through a downstream extrusion die. The solids conveying section of the barrel has a cross-section comprising a plurality of flat or slightly curved surfaces which extend substantially tangentially relative to the extrusion screw circumference, providing axial recesses which restrain the rotation of the solid extrusion material with the screw as it is moved axially into the compression section. The present machine and process causes plastic extrusion composition to be packed as a non-rotating mass to fill the solids-conveying and compression sections and increase the dead head pressure and extrusion output of the machine.

Abstract: The present invention relates to a rotation screw for mixing, for use with an extruder for forming by forcing out a volume of synthetic resin or a mixture of synthetic resin with additives including glass or carbon fiber, calcium carbonate, etc, having a series of centrally situated mixing recesses of large width and a plurality of mixing recesses of small width arranged on both sides of said wide mixing recesses, both of which are helically formed, in specified mixing positions, in the periphery of the rotational screw, arranged in helically adjoined relationship, and partially communicated transversely of the helical direction with one another so that the amount of delivery becomes great and the highly intimate mixing can be effected.

Abstract: This invention is directed to a worm shaft assembly used to move corrosive and/or abrasive material such is part of an extrusion device or a press. More particularly, it relates to the construction of flights, feed quills and intermediate rings or collars for mechanical presses and extrusion devices.

Abstract: A screw mill, for example, used for producing fine powder grains of calcium carbonate used as a bulking agent for paper. According to the screw mill of the present invention, the combination of the continuous screw and discontinuous vanes makes it possible to efficiently grind both slurry and dry materials without causing clogging of the mill. Also the clearance between the hub and the rotor can be finely adjusted by the screw type adjustor. This makes it possible to easily adjust the grain size and to produce ground materials having the spheroidicity of 0.3-0.03 which is best suited for use as a bulking agent for paper.

Abstract: Extrusion process and apparatus, the apparatus including an extrusion barrel having axial grooves which extend through the feed section and solids conveying section and disappear at the exit end of the compression section. The apparatus also includes a helical thread extrusion screw having a maximum channel depth in the feed section, which depth disappears at the exit end thereof. The process and apparatus causes plastic extrusion composition to be packed as a non-rotating mass to fill the solids-conveying and compression sections and increase the dead head pressure and extrusion output of the apparatus.

Abstract: A plasticating extruder with a screw having a feed section, a transition section, a metering section, a first primary flight located substantially in the first two sections, a second primary flight located substantially in the last two sections and two corresponding secondary flights located in the transition section, all the flights in the latter section radially balancing each other, and the first primary flight in the feed section balancing radially the second primary flight in the metering section. In another embodiment, the screw can in addition have a mixing section and another metering section, the latter having a flight balancing radially other flights in other sections.

Abstract: An extruder screw designed to operate in a continuous diameter barrel-type housing having a variable flight width, helix angle and radical clearance along the length of the extruder screw to reduce extruder screw induced power consumption and stock temperature generation in the manufacture of linear low density polyethylene plastics.

Abstract: The present invention relates to a novel extruder screw and method for extruding low melt viscosity polymers which form an anisotropic melt phase. In a preferred embodiment, the method and apparatus according to the present invention employ a high rate of rotational speed of the extruder screw in combination with a relatively low compression ratio and a high volume rate of flow through a compression section in order to effectively extrude the low melt viscosity liquid crystalline polymers. The particular design of the screw is dictated by the unique rheology of the polymers which are difficult to effectively move along the helix of the screw due, in part, to the extremely low viscosity. Each dimension and each relative size of the various sections of the screw must be carefully controlled in order to effectively extrude the unique material.

Abstract: A plasticating apparatus including a rotating screw having a helical flight disposed within and cooperating with the inner wall of a heated barrel. Resinous material is introduced to a helical valley extending along said flight to be plasticated by said screw and advanced towards an outlet opening. The screw has a metering section for working said resinous material at high temperature. The bottom surface of the helical valley in said metering section is divided into side by side relatively shallow and relatively deep levels having a depth differential therebetween. The relatively shallow and relatively deep levels extend along the bottom surface of the helical valley in side by side helical paths. The side by side helical paths have a different pitch than the pitch of the helical flight so that the helical flight periodically interrupts the helical paths.