Abstract: A continuous process of preparing a heat-vulcanizable filled silicone composition, comprises mixing filler and high viscosity silicone polymer continuously in a first co-rotating intermeshing twin screw extruder; and compounding a filler and silicone polymer mixture from the first extruder in a second single shaft reciprocating extruder. Another continuous process of preparing a heat-vulcanizable filled silicone composition, comprises forming a premix? of filler and high viscosity silicone polymer; mixing the premix and additional high viscosity silicone polymer continuously in a co-rotating intermeshing twin screw extruder; and compounding a filler and silicone polymer mixture from the co-rotating intermeshing twin screw extruder in a second single shaft reciprocating extruder.

Abstract: A screw element includes an outer radius Ra and a core radius Ri for multiscrew extruders with co-rotating and intermeshing screw shafts. The screw element has in axial cross section through its longitudinal axis a profile which has at each of the two axial end faces (i.e. a front end face and a rear end face) only one screw flight corresponding to a conventional single-start screw element for intermeshing screw shafts. In this case, the width (flight land angle ?) of the screw flight and conversely, in a corresponding way, the width (flight land angle ?) of the screw flight are formed in a special way and a shearing flight with a constant shearing flight radius Rs, which is greater than Ri, and less than Ra, is provided.

Abstract: The present invention includes a screw tip for an extruder screw for effecting mixing in an extruder. The screw tip has a substantially conical outside surface and at least one discontinuous fin. The at least one fin protrudes from the outside surface of the screw tip.

Abstract: High levels of treated fumed silica, processing fluid and high molecular weight silicone polymer are continuously compounded into a homogeneous silica filled heat-vulcanizable silicone composition by forming a premix in a continuous annular layer mixer and continuously discharging the premix into a compounding apparatus for compounding to form the filled heat-vulcanizable silicone composition.

Abstract: A continuous kneading apparatus and method are provided wherein discharge ports are provided at a plurality of positions of the barrel to discharge a kneaded product, and one of the plurality of the discharge ports is selected according to a desired kneading condition so as to discharge the kneaded product from only the selected discharge port. Another continuous kneading apparatus and method are provided wherein a plurality of charging ports are provided at a plurality of positions of the barrel to supply a material to be kneaded into the chamber, and one of the plurality of charging ports is selected according to a desired kneading condition. The kneading apparatuses and methods permit adjustment and control of a viscosity and a dispersion degree of a compounding agent over a wide range, and continuous kneading to achieve significant rationalization of a process for producing a kneaded product.

Abstract: An extruder for processing of thermoplastics has a housing (1) in which a screw is pivotally supported. A land (5) which runs in a helical line protrudes from the core (4) of the screw. There is at least one ventilation opening in the housing in which the screw is pivotally supported. The land (5) of the screw at least in the area of the ventilation opening has an active flank, i.e. one which points toward the discharge end of the extruder and which encloses with the axis of the screw an acute angle such that at least in areas it is set back relative to a radial plane which passes through the outside edge (14) of the active flank (10). This prevents the plastic which is to be processed in the extruder from being pressed to the outside and clogging the ventilation opening.

Abstract: An apparatus for degassing plastic materials, e.g., high molecular weight polycarbonate solutions, is described. The apparatus includes a double-shaft extruder having a length-to-diameter ratio of less than or equal to 40, which comprises: (i) two co-rotating and meshing shafts; (ii) an intake opening; and (iii) upstream and downstream portions relative to the intake opening. The shafts of the extruder are designed with a double lead in a degassing zone, and with a triple lead in a pressure build-up zone. Each of the degassing and the pressure build-up zones are down-stream from the intake opening, and the pressure build-up zone is further down-stream than the degassing zone. Also described is a process for degassing plastic materials, which involves providing the described double-shaft co-rotating extruder, into which plastic material is fed, processed and degassed.

Abstract: A twin-screw extrude having a novel fractional element has been invented that can provide different tip angles. The twin-screw extruder is suitable for processing thermo plastic, thermo set and other material. It has a barrel with two parallel intersecting bores, two sets of co-rotating fully intermeshed extruder elements that are linked to each other in non rotary manner forming continuous chain, each element operating in one of the bores and each screw being provided with multi lobbed elements that has special geometry.

Abstract: An apparatus for homogenizing and/or dispersing at least one viscous substance and at least one solid and/or at least one other substance of different viscosity has in a space (3) in the housing (1) axis-parallel rotatable shafts (4) disposed along a circle with equal central-angle distance and provided with tightly intermeshing screw elements (6). The shafts (4) in the area outside the openings (9, 11, 12) in the housing (1) are provided with screw elements (6) having a pitch (S) of at most three quarters of the outside screw diameter (D) over a length (L=L1+L2+L3) corresponding to at least ten times the outside diameter (D) of the screw elements (6).

Abstract: The invention relates to a screw element with an outer radius Ra and a core radius Ri for multiscrew extruders with co-rotating and intermeshing screw shafts, in particular for twin-screw extruders, which has in axial cross section through its longitudinal axis (10) a profile which has at each of the two axial end faces (front end face 8, rear end face 8′) only a screw flight (1, 1′) corresponding to a conventional single-start screw element for intermeshing screw shafts. In this case, the width (flight land angle &phgr;) of the screw flight (1) and conversely, in a corresponding way, the width (flight land angle &phgr;) of the screw flight (1′) are formed in a special way and a shearing flight (7) with a constant shearing flight radius Rs, which is greater than Ri and less than Ra, is provided.

Abstract: A multi-shaft extruder is disclosed with at least two shafts for compounding and/or molding an elastomer staggered with filler, in particular rubber, with at least one softener and/or additives.

Abstract: The invention relates to a screw pump comprising an inlet cross-section and an outlet cross-section for conveying free-flowing media, in particular plastic melts and rubber blends. Said pump comprises two screw shafts (20, 21), having a distance (&agr;) between their axes, which are located in a pump housing (3) comprising two partially overlapping housing bores (4, 5) that run through said housing (3) in a longitudinal direction and which can be rotationally driven in an equidirectional manner. A plurality of single-flight screw element groups (1, 2), which closely intermesh, are arranged on said shafts in a rotationally-fixed manner. The invention also relates to a multi-screw extruder comprising a screw pump of this type.

Abstract: An extruder for polymer melts, with an extrusion space arranged in an extruder barrel and through which at least one extruder screw shank extends so that it can be rotated by a motor. The screw shank has at least one section in the form of a cylinder casing, the extrusion space having at least one barrel section which surrounds the cylinder casing in an essentially equidistant manner to form an encircling gap as a restricted flow zone (blister), in particular to set the pressure of the melt. The clearance of the encircling gap at the restricted flow zone can be changed in a specifically selective manner by externally adjustable force, with elastic deformation of the inside surface of the extrusion space and/or of the surface of the screw shank, by a hydraulic pressure chamber provided in the region of the restricted flow zone in the wall of the barrel section and/or in the least one screw shank.

Abstract: The invention relates to a multi-screw extruder for the continuous treatment and/or processing of a bulk material, especially a product in powder, granular or flake form, comprising several shafts (3) which are arranged in a ring shape in a cavity (1) of an extruder housing (2) and which extend parallel to the axial direction (A) of the extruder. The extruder housing (2) is provided with axially parallel, concave segments (5a, 6a) of a circle on the radially inner (5) and radially outer (6) surfaces of the cavity (1). These circle segments act as a guide for the axially parallel shafts (3) with their processing elements (4) on the inside (5) or on the outside (6) of the shaft ring (3 . . . ). The inventive improvement lies in the radial extension of the axial partial area of the cavity (1) containing the shafts (3), which is located in the area of the feed opening (9), this radial extension (10b) extending along part of the shaft ring (3, . . . ) in the peripheral direction (U) of the same.

Abstract: A twin-screw continuous kneading apparatus is provided which can stably supply an additive without reducing the production capability and greatly increase the throughput of a high-quality compound. The kneading apparatus includes a second supply unit connected to an upstream end or a midstream portion of a barrel and supplying an additive into kneading chambers, and has a kneading zone provided by a part of each of kneading screws downstream of the second supply unit for mixing the additive into a kneaded material.

Abstract: An improved twin screw extruder device (14) is provided which is capable of producing a wide variety of high quality extrudates having greatly varying final properties, without the need for extensive machine modifications. The extruder (14) includes a barrel (16) together with a co-rotating twin screw assembly (22). The assembly (22) is made up of a pair of screws (50, 52) having central, tapered shafts (54, 56) equipped with outwardly extending helical flighting (58, 60); the screws (50, 52) are non-parallel and are positioned so that the flighting (58, 60) thereof is intercalated along the length of the screws (50, 52). The flighting is of specialized configuration and tapers along the length of the screws (50, 52) preferably at an angle of taper different than that of the shafts (54, 56); moreover, the width of the outer flighting surfaces (70, 72) increases along the length of the shafts (54, 56).

Abstract: A tip for an extruder screw includes a body having a first end for attachment to a screw, a second end, and an outer surface. A wiper extends outwardly from an outer surface of the body. In one embodiment, the wiper is a substantially helical conveying flight. In another embodiment the tip includes at least two substantially helical conveying flights on the outer surface of the body.

Abstract: An improved twin screw extruder device (14) is provided which is capable of producing a wide variety of high quality extrudates having greatly varying final properties, without the need for extensive machine modifications. The extruder (14) includes a barrel (16) together with a co-rotating twin screw assembly (22). The assembly (22) is made up of a pair of screws (50, 52) having central, tapered shafts (54, 56) equipped with outwardly extending helical flighting (58, 60); the screws (50, 52) are non-parallel and are positioned so that the flighting (58, 60) thereof is intercalated along the length of the screws (50,52). The flighting is of specialized configuration and tapers along the length of the screws (50, 52) preferably at an angle of taper different than that of the shafts (54, 56); moreover, the width of the outer flighting surfaces (70, 72) increases along the length of the shafts (54, 56).

Abstract: An extruder for processing of thermoplastics has a housing (1) in which a screw is pivotally supported. A land (5) which runs in a helical line protrudes from the core (4) of the screw. There is at least one ventilation opening in the housing in which the screw is pivotally supported. The land (5) of the screw at least in the area of the ventilation opening has an active flank, i.e. one which points toward the discharge end of the extruder and which encloses with the axis of the screw an acute angle such that at least in areas it is set back relative to a radial plane which passes through the outside edge (14) of the active flank (10). This prevents the plastic which is to be processed in the extruder from being pressed to the outside and clogging the ventilation opening.

Abstract: In an internal mixer, the bearing housings of the bearing arrangements for the journals of the rotors are mounted directly on the end walls of the housing. The gaps which are formed between the rotor and the end wall and between the journal and the end wall are connected to the outside by way of outlets. These outlets bridge the bearing which is encapsulated in the bearing housing.

Abstract: An improved twin screw extruder device (14) is provided which is capable of producing a wide variety of high quality extrudates having greatly varying final properties, without the need for extensive machine modifications. The extruder (14) includes a barrel (16) together with a co-rotating twin screw assembly (22). The assembly (22) is made up of a pair of screws (50, 52) having central, tapered shafts (54, 56) equipped with outwardly extending helical flighting (58, 60); the screws (50, 52) are non-parallel and are positioned so that the flighting (58, 60) thereof is intercalated along the length of the screws (50,52). The flighting is of specialized configuration and tapers along the length of the screws (50, 52) preferably at an angle of taper different than that of the shafts (54, 56); moreover, the width of the outer flighting surfaces (70, 72) increases along the length of the shafts (54, 56).

Abstract: A method for processing an impact modifier material having a core and shell molecular structure comprises working the impact modifier material in a mild extruder to a state such that at least a portion of the shells of the impact modifier material fuse together to form an impact modifier material output, and pelletizing the impact modifier output. The output is preferably pellitized, and produces pellets having a narrow size distribution.

Abstract: A continuous kneading apparatus and method are provided wherein discharge ports are provided at a plurality of positions of the barrel to discharge a kneaded product, and one of the plurality of the discharge ports is selected according to a desired kneading condition so as to discharge the kneaded product from only the selected discharge port. Another continuous kneading apparatus and method are provided wherein a plurality of charging ports are provided at a plurality of positions of the barrel to supply a material to be kneaded into the chamber, and one of the plurality of charging ports is selected according to a desired kneading condition. The kneading apparatuses and methods permit adjustment and control of a viscosity and a dispersion degree of a compounding agent over a wide range, and continuous kneading to achieve significant rationalization of a process for producing a kneaded product.

Abstract: A process and an apparatus for the production of paper products, such as “cat litter” or paper fuel, comprising reducing paper to a particulate form by shredding and grinding, conveying the particles of paper from a hopper as a layer on a first conveyor firstly beneath a leveling and compacting roller and thereafter beneath a set of water sprayers, before discharging from the conveyor onto a second conveyor with the assistance of a rearwardly baffle plate to invert the layer during transfer. The inverted layer on the second conveyor passes to a third conveyor belt which moves through a ring with has the effect of wrapping the belt over itself and around the mix to form a tunnel enveloping and compacting the mix to form an extrusion. The paper product as extruded is cut into pellets before subjecting the pellets to dehydration. In the case of paper product to be used as paper fuel, the paper is mixed with coal dust.

Abstract: The invention relates to an extruder in particular for processing polymer melts, with an extrusion space (4) which is arranged in an extruder barrel and through which at least one extruder screw shank (2) extends in such a way that it can be rotated by a motor, said screw shank having on it at least one section (5) which is in the form of a cylinder casing, the extrusion space (4) having at least one barrel section (1) which surrounds in an essentially equidistant manner the at least one extruder screw shank (2) in the area of the at least one region (5) in the form of a cylinder casing to form an encircling gap (17) as a restricted flow zone (blister 15), in particular to set the pressure of the melt.

Abstract: An extruder includes a barrel having a die attached to one end and at least one material inlet with a feeder for providing material to the material inlet. At least one screw is rotatively mounted in the barrel, and a motor is provided for driving the screw. A plurality of sensors is mounted in the barrel for sensing passage of screw thread edges as the screw rotates. A controller for controlling operation of the extruder receives signals from the sensors and determines local torsional deformations of the screw based on the signals. The controller slows down the extruder if any one of the local torsional deformations falls outside of an optimal range.

Abstract: The mixing element has a central hole for keying to the shaft of the screw and an outer profile which can be produced as a result of the removal of material from a circular element along at least one arc of its Outer portion by cutting performed by a point-like element rotating around a circle with a diameter equal to that of the circular element. The point-like element and the circular element rotate in the same direction and at the same speed and the centers of the circular element and of the circle are spaced apart by a distance less than their diameter. During a portion of the cutting process, the distance between the centers of the circular element and of the circle is reduced so that the portion of the outer profile which is correspondingly cut is recessed.

Abstract: Polyethyleneterephthalate extrusion equipment of material in granule form, still humid, coming from both ground recovered products and also virgin material, comprising a chassis (29), containing a co-rotating, oil-thermoregulated extruder with two screws (31, 32), which comprises a first zone (A), equipped with an opening (34) where there is an aspiration hood (35) for a first “open top” degassing, a second zone (C) where there is at least one stack (37, 38) for a further degassing, between the two zones (A, C), there being a tight zone (B), and a carrying and loading zone (E) activated by the screws (31, 32).

Abstract: A twin-screw continuous kneading apparatus is provided which can stably supply an additive without reducing the production capability and greatly increase the throughput of a high-quality compound. The kneading apparatus includes a second supply unit connected to an upstream end or a midstream portion of a barrel and supplying an additive into kneading chambers, and has a kneading zone provided by a part of each of kneading screws downstream of the second supply unit for mixing the additive into a kneaded material.

Abstract: An internal batch mixing machine includes a mixing chamber having a pair of cavities in which a first and a second rotor are mounted adjacent one another and are driven in opposite directions to mix material. The circumference of each rotor is divided into first, second, third and fourth sequential quadrants spaced in a direction opposite to the intended direction of rotation of that rotor. Each of the rotors has preferably a pair of lobes or wings located in every other quadrant of that rotor, although three lobe rotors are possible. Each lobe has a leading end and a trailing end. The first rotor has a pair of lobes located in its first and third quadrants, while the second rotor has a pair of lobes located in its second and fourth quadrants. One of the lobes of each pair of lobes is longer than the other, and each lobe extends downstream at an acute cohelix angle toward the other lobe of its pair.

Abstract: A compact extruder with multiple parallel screws having a variable pitch arrangement, includes an outer casing which has at least two chambers that contain at least two screws which allow material to flow from one chamber to the other chamber through a passage, and that present a feed inlet for the material to be treated and an outlet for the material; each chamber has at least one pair of housings for the corresponding pair of screws which engage with one another, each screw presenting a long-pitch portion and a short-pitch portion.

Abstract: A vent passage (28) extends from a main extruder passage (24) and is spaced from and between a feed extruder passage (26) and a back surface (16) of the barrel (10). The barrel (10) is characterized by the vent passage (28) being disposed to extend from the top surface (12) into the main extruder passage (24) and a vent passage adapter (36) in the vent passage (28) for controlling the venting of gases. The vent passage adapter (36) includes a restrictor member (44) extending downwardly from a mounting plate (38) to form a restricted passage (46) with a screw cover (40). The restrictor member (44) is removably attached to the mounting plate (38) whereby it may be removed for a less restricted venting of gases.

Abstract: A feeding method and apparatus are provided for a extruder which is used for processing of rubber, plastic and cellulose etc. The feeding apparatus comprises an inlet, through which the materials enter the apparatus; a screw for transferring the materials from the inlet by rotating, which has helical flights and extends along the transfer direction of materials; a feeding roller at the inlet which has helical flights and extends along the transfer direction of materials. The helical flights of the screw and the helical flights of the roller are engaged untightly. The method comprises: providing a feeding roller at the inlet, the roller extending along the transfer direction of materials and having helical flights which mesh with the helical flights of the screw; making the helical flights of the roller engage the helical flights of the screw untightly; making the roller and the screw rotate in opposite directions when the extruder operates.

Abstract: The invention relates to a method for dehydrating a two-phase liquid mixture consisting of a thermoplastic synthetic melt phase and an aqueous phase, comprising the following steps: a) coagulation of the two-phase liquid mixture in a first extruder; b) dehydration of the coagulate in a twin screw extruder with a de-watering zone and screws working in an opposite direction; c) separation of constituents by degasifying. The inventive method is characterized in that a single screw extruder or a twin screw extruder with screws working in the same direction is used as a first extruder in step a).

Abstract: In order to position the screw elements (6) axially precisely on the shafts (1) of a multi-shaft screw-type machine, a split stop ring (8) against which the screw elements (6) are prestressed is provided in a first ring groove (9) of the shaft (1). Spaced from the first ring groove (9), a second ring groove (11) with a screw thread (14) is provided. A straining ring (18) to be prestressed against the stop ring (8) and connected with the shaft (1) so as to rotate in unison is in screw connection with the screw thread (14).

Abstract: A machine for continuous processing of flowable materials has at least one shaft (4) with worm or similar processing elements (9, 15, 16). The housing (1) has at least one material inlet (14) at one end and at least one material outlet at the other end. The housing (1) is further provided with a flange (22) to which the driving member (8) is fastened with tension rods (28). The flange (22) is disposed so as to form between it and the driving member (8) a housing portion (13) with the material inlet (14) which is largely relieved of tensile forces. In order to also relieve the housing portion (13) of torques, the flange (22) is in addition connected so as to rotate in unison with a frame (27) to which the driving member (8) is fastened.

Abstract: A machine for continuous processing of flowable materials has a plurality of axis-parallel shafts in a space in a housing along a circle. Each shaft includes shaft bearing processing elements which tightly intermesh adjacent shafts. Between a material inlet at one end of the housing and a material outlet at the other end thereof, the housing jacket is divided radially into short segments with further passages and long segments, the length of the long segments being smaller than the outside distance thereof.

Abstract: A twin screw extruder has a casing with a working direction, two partially intersecting casing bores, which are parallel to each other, two shafts, which are disposed in the casing bores and which are drivable to rotate in the same direction of rotation about an axis of rotation, the axes of rotation having a distance A from each other, and single-flight kneading disks, which are fixed on the shafts and have surface lines extending parallel to the respective axis of rotation. The kneading disks, in a cross-section perpendicular to the axis of rotation, have a crest, which is formed as a segment of a circle about the respective axis of rotation and which has a crest angle b and a radius RA, a bottom, which is formed as a segment of a circle about the respective axis of rotation and has a bottom angle g and a radius RI and two flanks, which join the crest and the bottom, RA>RI, A≈RA+RI and 0°≦b≦45° applying.

Abstract: A method of making polymeric particulates wherein polymeric scrap material, virgin polymeric material and mixtures thereof are supplied to intermeshing extruder screws which are rotated to transport the polymeric material along their length and subject the polymeric material to solid state shear pulverization and in-situ polymer compatibilization, if two or more incompatible polymers are present. Uniform pulverized particulates are produced without addition of a compatibilizing agent. The pulverized particulates are directly melt processable (as powder feedstock) and surprisingly yield a substantially homogeneous light color product.

Abstract: There is provided a multi-shaft kneading disc, kneading disc block, and a multi-shaft extruder containing the same. The kneading disc and each kneading disc in the kneading disc block having a disc shape with a central section defining an extruder shaft mounting bore and at least one lobe extending radially from said central section and having a crest end. The at least one lobe has a radius X which defines an outer diameter of the kneading disc. The central section has a radius Y which defines an inner diameter of the kneading disc. At least one other lobe extends radially from the central section and has a radius Z. The radius Z defines the outer diameter of at least one other lobe. The radius Z of the other lobe is equal to Y+⅞(X−Y) to Y+¼(X−Y).

Abstract: A process for preparing thermoplastics or polymer blends comprising (A) from 5 to 95% of a water-moist elastomer component containing up to 60% of residual water, (B) from 5 to 95% of a thermoplastic polymer, (C) from 0 to 95% of a further polymer, and (D) from 0 to 70% of additives, said process comprising mixing the components A to D in an extruder with mechanical dewatering of component A, wherein the extruder has at least two rotating screws and, in the conveying direction, is essentially composed of a metering section into which component A is fed, a squeeze section which serves for dewatering component A and contains a retarding element and an associated dewatering orifice which is present upstream of the retarding element by a distance corresponding to at least one screw diameter, a feed section in which the thermoplastic polymer B is introduced as a melt into the extruder, a plastication section with mixing or kneading elements, a devolatilization section with an orifice and in which the remaining wat

Abstract: A screw extruder (10) having a barrel (18) which has a bore (26) defining an inner surface (44) and one or more extruder screws (28), positioned within the bore (26). The extruder screw or screws (28) include a central shaft (34) and one or more screw flights (30). The extruder screw or screws (28) farther including one or more dispersive mixing elements (204), (234), (308), (406), (508), (558), which interact with the inner surface of the barrel (44) to form one or more progressively narrowing passages (46) through which material is forced into multiple regions of high elongational and shear stress (480, (120), (214), (310), (410), (510), (564).A second preferred embodiment is a screw extruder (10) having a barrel (18) having a bore (26) defining an inner surface (44) and one or more extruder screws (600), (701), positioned within the bore (26).

Abstract: A mixing element for a screw extruder comprises an element including opposing lobes and a central portion having common opposing broad surfaces; one lobe broad surface being formed into a taper. The elements may be used individually or combined in blocks, with the elements of a block oriented in various combinations. The blocks may comprise two or more elements. The tapered lobes provided reduced pressure and temperature of the process as compared to prior art mixing elements. Also, more graduated control over temperature and pressure are provided according to the value of the taper magnitude, the number of elements used in a process and the relative lobe orientations in a machine.

Abstract: A single flighted multi-screw conveying bushing that has only one helical screw element extending the length of the bushing. The bushing has a cross-section shape that has a segmented circular base and a lobe extending from the base. The lobe has a truncated crest that is sized to have a circumferential angle of from 15.degree. to 30.degree. and preferably from 22.degree. to 24.degree.. Also, a twin screw extruder having a pair of side by side drive shafts with at least two of the single flighted screw bushings mounted end to end on each shaft.

Abstract: The invention relates to a multiscrew, continuous mixing machine for plasticizable compounds with two screws, which rotate in the same direction in a housing and which penetrate the cylindrical part of the housing that envelopes the screws. The screws include axially spaced apart conveying sections and at least one mixing section therebetween. The conveying sections are formed by intermeshing conveying screws. The mixing section is formed by mixing elements. The mixing elements are followed by restricting elements which include short screw elements with back feed thread. The back feed thread forms a vertex, which progresses radially shortened along a thread in such a way that the radius of the vertex is shorter on the inlet side than on the outlet side and inbetween increases continuously towards the outlet side.

Abstract: A twin shaft continuous kneading extruder has a twin kneading feeder portion provided with two passages juxtaposed to each other within a casing. The passages are cocoon-shape in cross-section and hold two kneading shafts rotatably disposed in the respective passage portions. A single screw portion substantially extends one of the passages and holds a screw shaft that substantially extends one of the kneading feeder shafts. In addition, a plurality of mixing portions are provided on the twin kneading feeder portion. A first degassing open vent communicates with the kneading feeder shafts between mixing portions while a second vacuum degassing open vent is provided on the single screw portion. The first mixing portion keeps resin fed from a material feeding port in a semi-gelled condition. Thereafter, the resin is completely melted and kneaded in a second mixing portion after degassing. The resin is then fed to the single screw portion which subjects the resin to a vacuum degassing to be further extruded.

Abstract: A corotating multiple-screw extruder comprising first and second intermeshing screws of more than one flight. The first screw comprises first and second segments paired with first and second segments of the second screw, respectively. On the first segment of the first screw, the height of the first flight is less than the height of the second flight and on the second segment of the second screw, the height of the first flight is less than the height of the second flight and screws for use in such extruder.

Abstract: A multi-shaft screw-type extruder having a casing with two parallel intersecting casing bores and two shafts drivably disposed in the casing bores. Screw elements intermeshing kneading disks are fixed on the shafts The widths of the respective crest portions of the kneading disks are smaller than the disk width and form mixing-and-scraping-studs on the periphery of the disks. The mixing-and-scraping-studs on each kneading disk are axially misaligned relative to each other such that their peripheral faying surfaces jointly cover the entire disk width.

Abstract: A screw extruder mechanism for the processing of strongly outgassing materials comprises a main extruder for proper material processing, a material feed and discharge device and a degassing device on the main extruder for the discharge of the gas stream from the portion of evaporation. For the gas stream to branch into at least three separate streams, the degassing device comprises a first degassing port and at least two degassing elements which are opposed radially to each other in relation to the main extruder and are disposed between the portion of evaporation and the first degassing port and which are designed preferably as ancillary screw extruders opening radially into the main extruder.

Abstract: A multiple-screw extruder in which paired co-rating screws, or segments thereof, contain unequal numbers of flights; and a screw for use in such extruder.