Abstract: A twin screw extruder and torque splitting transmission has two output shaft portions that are axially spaced apart a distance and are connected to elongate shafts where at least one is bent along its length and powered by a driven pinion gear that has a diameter that is greater than the distance between the axes of the twin screws.

Abstract: A mixer for viscous liquids and masses has a stationary first housing of circular cross section preferably disposed horizontally with inlet and outlet means for the material to be processed and surrounding a driven inner coaxial rotatably mounted second housing. The annular space jointly limited by the two housings with closing portions disposed on the faces contains a number of axially parallel mixer shafts driven in the same direction and disposed in a ring which perform a common revolving motion about the longitudinal axis of the housing. The mixer shafts extend with their envelopes as far as the inner and outer walls of the two housings leaving small gaps free. The mixer shafts formed as screw conveyors at least in portions are combined into meshing groups.

Abstract: An extruder in which the joint between the downstream, forward end portion of a cylinder and a gear pump is always kept tight, so that molten resin material is prevented from leaking out. As the main discharge port of a diverter valve is prevented from shifting from the inhalation port of the gear pump at the joint therebetween, the flow passage at the joint is always smooth without a spot where the molten resin material collects. The quality of resin products thus becomes stable.

Abstract: A method of extruding a substantially uniform polymer composition made up of polyvinylchloride, a stabilizing additive composition and at least one of two additional constituents, one of which is a mineral filler and the other of which is a normally liquid plasticizer for the polyvinylchloride; the method is achieved while avoiding use of compounded PVC as a starting material and includes the steps of: (I) providing an extruder; (II) operating the rotors of the extruder for essentially synchronous rotation in a common direction while maintaining in the extruder cavity a temperature sufficient to plasticize the polyvinylchloride; (III) feeding particulate polyvinylchloride and the additive composition without substantial premixing of the polyvinylchloride and the additive composition into the cavity at the first inlet (e.g.

Abstract: In a thermoplastic material extrusion line having a melt extruder, a gear pump, and a die aligned with one another, the gear pump is supported on a hinged articulable arm for swinging movement into and out of operative disposition in alignment with the extruder to simplify realignment of the gear pump with the extruder and the die whenever it becomes necessary to remove the gear pump from the line for maintenance or service.

Abstract: A hydraulic control device for a closed type kneader, including a sealing surface pressure applying circuit for applying a sealing surface pressure to a sealing device for sealing a rotor accommodated in a kneading chamber, a drop door driving circuit for controlling an opening and closing operation of a drop door for closing a bottom surface of the kneading chamber, and a power circuit for supplying a pressure oil to the sealing surface pressure applying circuit and the drop door driving circuit. The sealing surface pressure applying circuit is connected to a pressure oil supply line in the drop door driving circuit for a closed condition of the drop door. Accordingly, when the application of the sealing surface pressure is unnecessary, that is, when the drop door is opened, the sealing surface pressure is prevented from being applied to the sealing device, thereby extending the life of the sealing device.

Abstract: Side by side extruders provide an extrusion apparatus which has an imposed order of longitudinal displacement of the process material in relation to itself so that cross-shearing is directed to newly aligned material in a manner which achieves volumetric blending with little unproductive shearing. The extrusion apparatus mixes and extrudes polymer like materials with as little waste shearing as possible, so as to preserve the viscosity of the polymer materials and to produce a uniformity processed material of the highest quality possible from the starting materials.

Abstract: An apparatus for continuously processing viscous liquids and masses has axially parallel satellite shafts (23) disposed in a ring within a housing (4) and driven in the same direction which bear meshing processing means (24) and are driven by a central shaft (17) bearing central gearwheels (19; 20). Each satellite shaft (23) bears two axially spaced coaxial pairs of pinions (27; 34), one pinion (28; 36) of each pair of pinions engaging a central gearwheel (19; 20) and the other pinion (29; 35) engaging the internal toothing of an annular gear (5; 9) fixed on the housing. The toothings of the pinions (28, 29) of one pair of pinions (27) are formed with a module which results in an integral number of teeth on the central gearwheel (19) or on the internal toothing of the annular gear (5) from satellite shaft (23) to satellite shaft (23). The central shaft (17) is supported on the annular gears (9, 10) only via the central gearwheels (19, 20) and the pinions (28, 29; 35, 36).

Abstract: A method of continuously making chewing gum base employs low pressure, adequate residence time, and the flexibility of selectively feeding different ingredients at different locations on the mixer. The method involves the use of a paddle mixer, characterized by a plurality of paddles mounted on a longitudinal rotating shaft, preferably mounted on two parallel co-rotating shafts. The paddles cover at least about 40 percent of the active length of the shafts. This configuration provides for significant residence time in the mixer and low pressure gum base manufacture.

Abstract: A continuous process and apparatus for making bread and bread-like products using supercritical fluid extrusion are disclosed. The process is carried out in a dough mixer and extruder into which supercritical CO.sub.2 is injected to provide proofing of the product. Rising of the dough is produced by a combination of hydrodynamic expansion of air bubbles and diffusion of CO.sub.2 into said bubbles as the dough is extruded through an exit die, without the need for yeast. A filler material may be introduced into the core of the extruded product by a coextruder located within the extruder, to provide a continuous process for producing a coextruded filled product consisting of a fully cooked cereal-based outer core filled with a pumpable filling injected into the hollow center of the product. Also, controlled acid hydrolysis of the starches in the dough may be used to produce reducing sugars that add desirable flavor to the final product.

Abstract: In a cone type twin screw extruder, two rotor shafts are disposed in such a manner as to approach one another in the direction towards the leading edge, and to be rotatable. An interlocking device is provided on the side of the base portions of the rotor shafts for interlockingly connecting the rotor shafts with each other. The interlocking device has a pair of reduction gear devices disposed on the base portion sides of the rotor shafts, and the reduction gear is constituted of a spur gear train or a planetary gear train. High speed shafts of the reduction gears are interlockingly connected with bevel gear devices, and one shaft of the bevel gear device forms a connecting shaft projecting from the other bevel gear device side. Further, a pair of the connecting shafts are interlockingly connected with each other by a coupling device.

Abstract: A method of manufacturing a rubber mixture includes the step of mixing at a first temperature in a batchwise operation a base mixture of rubber and non-reactive additives in a ram mixer. In a subsequent step the base mixture is removed from the ram mixer and formed to a strand. The strand is cooled to a temperature at which the strand is still warm. The warm strand is then fed to a ramless mixer and reactive additives are added. In a batchwise operation the base mixture and the reactive additives are mixed at a second temperature that is lower than the first temperature in order to form a finished rubber mixture. Preferably, cooling and feeding of the strand are performed simultaneously.

Abstract: The novel invention proposes a novel dough kneading process and a corresponding apparatus, wherein the dough is produced in a small lump structure in a rapidly revolving centrifugal kneader. A very high percentage of granulate sizes corresponding to the size of the desired final product can be produced directly with the new process in particular for further processing of the small lumps to form couscous. The individual small lumps have a complete protein structure when leaving the whirl kneader. For large throughput capacities, the whirl kneader is constructed as a double-rotor kneader. It is important that the minimum kneading time does not fall below at least 5 to 10 seconds and it would be more advantageous not to exceed a maximum kneading time of 2 to 3 minutes.

Abstract: A method for compounding at least one polymerized alpha-olefin resin in an extruder including a screw having a feeding section, a melting section, and a venting section, which method includes: (1) introducing the resin and a heat transfer medium into the feeding section such that the resin is maintained at a temperature below its melting point; (2) transporting the resin and heat transfer medium to the melting section such that the resin is at a temperature which is at or just above its melting point by sublimation or vaporization of the heat transfer medium and kneading the resin at a temperature which is at or just above its melting point; (3) passing a resin melt of step (2) through a melt seal into a venting section wherein the heat transfer medium is released from the extruder; and (4) pumping the resin melt out of the extruder.

Abstract: A noodle machine has a housing with an upper opening, a receptacle deposited in the housing for receiving flour and water for making dough for noodles by stirring them by rotation of a stirring shaft positioned horizontally in the receptacle and rotated by a motor. A front cap with a center cylindrical portion for a screw portion of the stirring shaft fits therein to squeeze out dough to go out through a sieve with holes fixed at the front of the cylindrical portion to become noodles. And a shutter hangs at a notch at an upper side edge of the receptacle for closing an opening of a U-shaped plate of the front cap for hampering dough from moving into the screw portion and removed to let dough move through the opening of the U-shaped plate to be squeezed out of the sieve to become noodles by rotation of the screw portion.

Abstract: An apparatus is disclosed for processing extrudable materials in such a way as to apply a controlled and predetermined degree of shear force to the materials. Typically, an extruder apparatus includes a housing having first and second screws mounted therein for rotation on a common axis, the arrangement being such that longitudinal thrust forces exerted by the first screw are at least partially compensated by corresponding forces generated by the second screw, inlet means for introducing material to be processed into the housing and a shear generating device located between said screws, said device including a restriction through which material is forced from said housing to exit from said housing. The restriction is preferably an annular gap formed by a sleeve fixed relatively to the housing and a shaft portion which extends into the sleeve.

Abstract: A continuous method of making chewing gum base is provided wherein two continuous mixers are arranged in series. A higher viscosity portion including elastomer, filler, and elastomer plasticizer is continuously added and mixed in the first continuous mixer to form a blend. The blend is ventilated after leaving the first continuous mixer. The blend from the first continuous mixer is continuously added to the second continuous mixer. A lower viscosity portion including softener/emulsifier and, optionally, wax and additional elastomer plasticizer, is also continuously fed to the second continuous mixer and mixed therein with the blend from the first continuous mixer to form chewing gum base.

Abstract: An apparatus for continuously processing viscous liquids and masses has axially parallel satellite shafts (23) disposed in a ring within a housing (4) which bear meshing processing means (24) and are driven by a central shaft (17) via pinions (28, 29) on the inlet side to perform a common revolving motion about the central shaft (17). The pinions (28, 29) have associated therewith a distributing plate (60) which is provided with through bores (61) for the satellite shafts (23) and has an annular groove (63) opening toward the inlet side, from which channels (64) lead into the area of the processing means (24) on the satellite shafts which is located on the thick-layer side of the satellite shafts (23) facing away from the enveloping housing (1).

Abstract: A process is provided for producing elastomeric compositions by forming a mixture of polymeric material, a reinforcing agent, a processing aid and a vulcanizing agent. The process of the invention is continuous and includes the repeated, sequential steps of admixing the polymeric material along a first mixing zone defined by a space wherein the gross energy applied induces a first operating temperature range. The mixture of the first zone is continuously passed into and through a second mixing zone while adding and admixing the reinforcement agent and processing aid therewith, the second mixing zone being defined by a space wherein the gross energy applied induces a second operating temperature range. The mixture of the second zone is then continuously passed into and through a third mixing zone while adding and admixing the vulcanizing agent therewith, the third mixing zone being defined by a space wherein the gross energy applied induces a third operating temperature range.

Abstract: A back mix, drag-flow apparatus that provides both radial and axial mixing of materials comprising at least two worms in screw form and parallel and tangential to one another that are of opposite hands and are rotatable only in the same direction or are of the same hand and are rotatable only in opposite directions; and a barrel casing completely enclosing said worms and containing a feed inlet and a product outlet.

Abstract: A plastifying extruder of the double-screw type, to avoid dead zones in the flow, has at its throttle location throttle disks on the screws formed with outwardly open recesses angularly equispaced on the disks. Pins distributed around the screws in the throttle region project radially into gaps between the disks and can penetrate to a greater or lesser extent into these gaps to provide a variable flow cross section.

Abstract: The process of manufacturing a thermoplastic organic material containing reinforcing fibers and optionally mineral materials and organic additives by combining the fibers and materials in an extruder, and introducing at least some of the organic material into the extruder in the form of continuous filaments or fibers.

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: An extruder having a reduced nip ratio and a process employing the same.

Abstract: A double worm extruder has the ribs of its screws of trapezoidal cross section between divergent flanks to minimize wear of the housing surface.

Abstract: In the preparation and production of plastic materials by a continuously operating double shaft screw-type extruder, the efficiency of production often depends on good delivery of material to the extruder. In accordance with the invention for processing various types of plastic materials, a primary stage is mounted in a pressure-tight sealed manner on the housing of the extruder, the primary stage being formed by a vertical double conical container in which a pair of screw-type helices are rotatably supported and driven from above. The helices are connected to two replaceable feed elements at their lower ends so that delivery of material to the extruder is achieved without any intermediate dead spaces.

Abstract: Material such as chewing gum is treated to reduce its density by working it and feeding it through a twin-screw corotating extruder configured to provide flow at first and second longitudinal rates, pulling in a plane normal to the axis of flow, and further working and homogenization.

Abstract: A process and apparatus for the production of a polymer of thermoplastic polycondensate in which the polymer is first treated in a screw extruder and then in a mixing tank. In the extruder the polycondensate is heated in a first zone to a temperature below its melting point and thereafter it is heated to a temperature above its melting point at a vacuum. Water and other volatile components are removed from the first and second zones of the extruder. In the mixing tank the polymer is maintained under vacuum conditions and is conveyed and mixed by spiral mixing blades to remove residual water and volatile components. The polymer is discharged at the bottom of the mixing tank by a melt pump after a residence time of between 5 and 60 minutes in the mixing tank.

Abstract: A process and a degassing unit for the degassing of plastic melt in a screw extruder in which a surface of the degassing unit facing the screws of the extruder are heated to prevent deposition of entrained plastic particles, particularly at the corners or edges of the degassing unit. Prior to the commencement of the treatment process, the degassing unit is heated to a temperature which is at least as high as the melting point of the plastic to be treated. Heating can be effected by conveying a heating medium through a channel in the degassing unit located in proximity to the surface facing the extrusion screws and especially the corner or edge regions.

Abstract: A continuous, self-wiping, multiple parallel shaft processing and/or extruding system wherein material is charged to a barrel in which the shafts extend at one end and discharged at another. The barrel has an interior chamber defined by parallel intersecting cylinders providing generally V-shaped saddles at their confluence, and parallel shaft rotate within the cylinders at the same speed of rotation and in the same direction of rotation Radially co-wiping helical processing elements are fixed respectively on the shafts and are configured to also wipe the walls of said cylinders. A vent for egressing volatiles leads from the chamber, and a vent bypass passage has a first section leading from the chamber upstream from the vent, a midsection extending coextensively with the chamber within the barrel, and a return section returning to the chamber.

Abstract: Apparatus for extruding plastic and/or rubber material has a screw extruder, which plasticizes the material and delivers it to a gear pump which develops sufficient pressure for extrusion of the material through an extrusion head. The apparatus is characterized by the fact that the axes of gears of the gear pump and the axis of the screw of the extruder are parallel to one another. The housing of the gear pump has a side opening into which a cylindrical bushing and the screw of the extruder extend so that the material is delivered by the extruder directly to the gear pump as a non-oriented plasticized mass. The extrusion head may be a transverse extrusion head with an axis parallel to the axes of the gear wheels of the gear pump and the axis of the screw of the extruder. A second like extrusion apparatus including a screw extruder and a gear pump may be connected to an opposite side of the extrusion head.

Abstract: A double worm extruder for kneading units along the worms which are rotatable in the same sense. Each kneading unit has three or more circumferentially offset polygonal disks which have sealing surfaces at diametrically opposite locations closely juxtaposed with the inner wall of the housing. These sealing disks are flanked by edges which are inclined to the axes of the worms so as to insure greater flow cross sections past the disks and thereby avoid shear peaks in the extruded material and thermal decomposition thereof.

Abstract: A method of preparing a magnetic coating composition comprises a first process for kneading ferromagnetic grains, a binder and a binder solution Y1 by use of a two-shaft continuous kneading and mixing machine to obtain a kneaded mixture K1 having a solid content within the range of 65 wt % to 95 wt %, a second process for kneading a binder solution Y2 and the kneaded mixture K1 by use of the two-shaft continuous kneading and mixing machine to obtain a primary diluted mixture K2 having a solid content within the range of 50 wt % to 70 wt %, a third process for diluting and dispersing the primary diluted mixture K2 in an organic solvent to obtain a secondary diluted mixture K3 having a solid content within the range of 25 wt % to 50 wt %, and a fourth process for finely dispersing the secondary diluted mixture K3 to obtain a dispersion mixture K4 having a solid content within the range of 25 wt % to 45 wt %.

Abstract: Cleaning of vacuum presses is facilitated by providing a vacuum press housing that is composed of pivotable housing elements which are in turn pivotally attached to the press frame. The horizontally hinged cylinder halves that serve as housing elements of the preliminary press are connected by way of a flange connection to a sieve plate holder which is likewise arranged on a U-shaped support of the press frame so that it is pivotally movable horizontally. Arranged displaceably at the other end of the press is a joint washer with radial and lateral sealing means. The vacuum chamber which can be raised and lowered vertically and which can be pivoted horizontally is releasably connected to the joint washer by snap closure means. Pivotal movement of the vacuum chamber is ensured by a hinge connection to the U-shaped support. The vacuum chamber is placed upon the filler opening of the lower press, and is secured by means of snap closure means.

Abstract: A twin screw extruder for processing plastic material having a housing provided with a plurality of juxtaposed housing segments arranged axially in succession and defining two longitudinal, overlapping bores respectively containing two coaxially arranged extruder screws, rotatable about respective longitudinal axes, and having intermeshing threads. One of the housing segments serves as a degassing housing segment for degassing the plastic material and it is connected to a degassing chamber. The degassing housing segment has a transverse, radial opening in which an insert member is fitted, the insert member having a degassing opening providing communication between the degassing chamber and the bores in the housing. The degassing opening tapers in widening fashion in the direction from the longitudinal bores to the degassing chamber, and the degassing opening has a longitudinal axis disposed in a plane passing through the longitudinal axes of the screws.

Abstract: A method is disclosed for the production of extruded plastic products by using an extruder (1) which has an extruder hopper (2) which is supplied with a hot mixture obtained by discontinuous mixing of PVC powder and aditives in a hot mixing zone, with the supply of frictional heat, wherein a first amount of PVC powder is mixed with an excess of additives with the supply of frictional heat, after which the mixture thus obtained is homogenised in the same mixing zone with a supplementary amount of PVC powder, in such a way that the final mixture has the desired concentration of additives, after which the hot mixture obtained after homogenisation is fed directly to the extruder hopper (2). An installation for the production of plastic products by extrusion, comprising a discontinuously operating hot mixer is also disclosed, as well as said hot mixer (3).

Abstract: The process is used to remove the solvent from an elastomeric polymer solution containing at least 8% by weight of elastomeric polymer. The elastomeric polymer solution undergoes a preprocessing step in order to remove a large part of the solvent. Thereafter, the elastomeric polymer solution is fed into a main extruder in order to remove the remaining solvent. The preprocessing step includes: (a) introducing a heating fluid and the elastomeric polymer solution into a static mixer in order to mix the heating fluid and the elastomeric polymer solution and heat rapidly the elastomeric polymer solution to a temperature of 60.degree.-250.degree. C.

Abstract: The invention relates to an apparatus for producing monodisperse powdered rubber and includes an extruder and individual conveying, grinding and discharge sections with respective cooling units corresponding thereto. The cooling units are arranged outside of the extruder and receive the grinding stock after each grinding process in order to cool and transport the stock to the feed opening of the following conveying, grinding and discharge section of the extruder.

Abstract: An apparatus for forming shaped material from a raw material employs a substantially cylindrical housing 3 with a screw shaft 2 arranged in it. A frontal end surface of the housing, located at the downstream end is closed by a counter-pressure member 9 which, together with the housing 3, limits a discharge opening. The counter-pressure member is held against conveyed material by a force of predetermined magnitude acting opposite the conveying direction. Surprisingly, this results in a high compactness and a good stability of shape of the shaped material, and also facilitates a starting of such an apparatus. Removable teeth define an orifice.

Abstract: Multi-screw, continuous mixing and kneading machine for plasticizable compounds with screws, which rotate in a housing and which penetrate the cylindrical housing section, enclosing the screw concerned, and exhibit feed and discharge zones and intermediate melting, mixing and kneading zones, where the feed and discharge zones are formed by intermeshing screws that rotate in the same direction, and kneading elements are disposed in the melting, mixing and kneading zones. The kneading elements comprise axially extended polygons, whose surfaces are approximately flat and whose edges travel by one another with small clearance relative to the envelopes of the respective other polygon so as not to intermesh while rotating, where the edges of the housing section enveloping them maintain a distance that is significantly greater than the clearance.

Abstract: A machine for manufacturing thermoplastic polymers including a plurality of coaxial components adjacent to and made integral with one another, the components forming a longitudinal chamber receiving a pair of interacting shafts having portions correspondingly differentiated to provide sections for feeding and premixing the compound, thus forming a single assembly with coaxial components capable for carrying out full processing of the compound from the raw material to extrusion, without discontinuity of sequence.

Abstract: A process is provided for modifying the residence time distribution of materials in an extruder which results in a residence time distribution comparable to that obtained in a continuous stirred tank reactor. An extruder is provided which has a section which modifies the residence time distribution of materials loaded into the extruder.

Abstract: Fibrous network structures are produced within liquid polymer resins by passing the fiber-containing resin along a channel having a plurality of sets of flow modifying elements which establish a regulated succession of velocity profiles for the principal flow direction and the two directions perpendicular thereto. The individual velocity profiles persist over distances which are small compared to the channel dimension over which they are established and are such that there is substantially no net deviation from the principal flow direction. The velocity profiles superimpose on each other to cause rotation and sliding of the fibers so that a coherent network structure is built up which persists through extrusion dies and molds into the solid state. By means of a large number of touches per fiber the structures thereby established confer efficient mechanical reinforcing properties and enhanced thermal properties on the polymer composition.

Abstract: A process for the continuous production of a rubber compound in a twin-screw extruder is disclosed that improves the dispersion of carbon black in the extrudate while reducing the specific energy requirements of the extrudate. Rubber is fed into the extruder together with a processing aid and masticated up to a temperature of 120.degree. C. to 180.degree. C. Subsequently, a first part of carbon black representing preferably 40% to 80% of the whole quantity of carbon black is fed into the heated extrudate. Afterwards, plasticizing oil is added to the extrudate before the second remaining carbon black part is fed and incorporated into the extrudate at a temperature of 120.degree. C. to 180.degree. C. The whole compound is then cooled, a crosslinking agent is added, and the compound is homogenized and extruded.

Abstract: A plastifier extruder of the double-screw type has a slide plate shiftable toward and away from the screws at an acute angle to the axes thereof in a chamber having a trapezoidal axial cross section between extreme positions in which a surface of the plate parallel to the axes lies along one long side of the trapezoid and another limiting position in which the surface lies along the other long side of the trapezoid.

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: The specification is concerned with a process and apparatus for continuous manufacture of moisture curable silicone compositions.

Abstract: A segmented barrel extruder device for extrusion and having a plurality of segments enclosing an extruder barrel aligned on an axis. The segments include axially perpendicular rectangular end flanges having exposed sides and a central portion for housing an extruder barrel. The flanges have aligned straight line paths for fluid flow in a plane perpendicular to the axis. Accordingly, the paths each intersect two exposed sides without intersecting the central portion. The segments also include an extruder bore between the flanges. The segments have a housing having straight axial channels which are connected to the paths in the flanges to conduct fluid from points along one path in each path to of points along a corresponding path. The extruder bore also includes a centered portion aligned with the flange central portion and a radial feeder device. The radial feeder device includes a seal and a mount which is adapted to mount the seal without sealing force on the bore.

Abstract: Method and apparatus for the electromagnetic dynamic plasticating of polymer materials includes a magnetic moving body which is supported both axially and radially by a magnetic levitation gap. The magnetic body is rotated in non-steady state vibration within an electromagnetic winding and cooperates with a stationary body to form a processing space for the polymer material.

Abstract: A device for feeding an extrusion head for plastic material includes a main extruder connected to a main die for extruding a continuous main flow of material, and an auxiliary feed mechanism associated with the main die and selectively controlled to cover the outer exit flow of the main die with a surface layer. The auxiliary feed mechanism continuously conducts two auxiliary flows, a first flow forming the surface layer and the second flow being mixed with the main flow. An invertor valve permits selective exchanging of the two auxiliary flows such that the second flow can cover the main flow and the first flow can be mixed with the main flow.