Abstract: An apparatus for impregnating fibrous strands with plastic material as matrix material including: an impregnating core having an outer limiting surface; an impregnating shell defining a cavity therein having an inner limiting surface, the impregnating shell completely enveloping the impregnating core and being disposed with respect to the impregnating core such that the limiting surfaces together define an impregnating channel therebetween, the limiting surfaces concentrically enclosing the impregnating channel along a joint symmetry axis such that the impregnating channel has a ring-shaped cross section in a plane transverse to the joint symmetry axis, the ring-shaped cross section having an outside dimension which diminishes by stages in a flow direction for the impregnation, feeding channels for the fibrous strands and the matrix material being defined at an intake side of the impregnating channel and a discharge opening for impregnated fibrous strands being defined at an exit side of the impregnating chan

Abstract: A baking oven comprises several oven modules disposed one after the other in the longitudinal direction, each of which comprising independently controllable heating devices and at least one supply duct for vapor and/or fresh air which leads to the hearths and at least one discharge duct for vapor and/or waste air which leads away from each hearth.

Abstract: An assembly for applying a torque from an output shaft to an input shaft of an apparatus, such as a multishaft extruder, and for measuring the applied torque. The assembly includes a connecting sleeve for torque-transmittingly coupling the output shaft with the input shaft; and a torque measuring device having expansion measuring strips, a signal amplifier, a transmitting ring antenna and a receiving antenna. The connecting sleeve has a first length portion carrying the expansion measuring strips and a second length portion carrying the signal amplifier and the transmitting ring antenna. A torque-transmitting arrangement torque-transmittingly couples solely the first length portion of the connecting sleeve with the output shaft and the input shaft, so that the second length portion of the connecting sleeve is free from a torque-transmitting connection with the input shaft.

Abstract: A screw-type extruding machine includes a housing; a driveable shaft disposed inside the housing and including a rotational moment transfer element; and at least one screw element. The screw element has two ends and defines a longitudinal groove therein for receiving the rotational moment transfer element of the shaft, the shaft thereby transferring its rotational moment to the screw element. The groove is configured such that it defines two expansion regions, each expansion region having an axial extent, the groove having side surfaces which diverge with respect to a longitudinal axis of the groove along the axial extent of each expansion region in a direction toward a corresponding one of the two ends of the screw elements, a width of the groove thereby increasing in a direction toward its two ends along each expansion region.

Abstract: A dough portioning machine comprises a metering chamber with a metering piston which is displaceable therein. The metering piston is provided with a degassing channel which is formed in the piston wall and to which a cleaning pin in the cylindrical wall of the metering chamber can be allocated.

Abstract: In an underwater pelletizing die plate or an extruder for the pelletizing of thermoplastics, the front face of the die plate, which is provided with a wearing protection layer and over which pass the pelletizing knives, being disposed under water, and heat isulation means being provided on the pelletizing die plate, good axial insulation is to be achieved, accompanied by uniform temperature distribution in the radial direction, it being provided to this end that an insulating layer is disposed between the external upper side of the actual pelletizing die plate and the wearing protection layer, the wearing protection layer being positioned, relative to the insulating layer, with radial play and without axial pressure or with little axial pressure, respectively.

Abstract: A stationary axle is secured adjacent to an extruder of plastic or other material forming a strand. A rotor rotates about the axle and carries a plurality of axially extending cutters for pelletizing the strand. The shaft has an internal fluid conduit carrying pressurized air. A sleeve is fixed to and over the shaft and has a recess forming a fluid manifold in communication with the conduit and the rotor. The recess has a given angular extent about the sleeve. A plurality of annularly spaced linear arrays of passages in the rotor communicate with the recess manifold in accordance with their angular position about the shaft. The passages of each array are aligned with the edge of a different cutter for sequentially generating arrays of streams of pressurized air impinging upon the cutters after pelletizing as the rotor rotates.

Abstract: A die plate for the underwater granulation of thermoplastic material is formed with a base plate of an iron alloy, a hard annular cutting plate of titanium-carbide alloy, and an intermediate buffer layer containing nickel between the base plate and the cutting plate to equilibrate heat stresses due to different coefficient of thermal expansion of the base and the cutting plates. The intermediate layer is formed with a thickness of between 0.5 and 2 mm by hot-isostatic pressing a nickel-containing metal powder between the plates such that the intermediate layer is diffusion welded to the plates. Two nickel layers with an intermediate titanium-containing plate can also be formed. Also an ansenitic layer can be formed between the nickel layer and the base plate.

Abstract: A twin-shaft screw-type extruding machine comprises a casing, shafts driven to rotate in the same direction of rotation and mixing elements facing each other and associated in pairs, which are disposed non-rotatably on the shafts. Each mixing element is a disk connected with a shaft. Mixing wings are provided at equal angular distances on the fronts, facing each other, of the disk and in the vicinity of the latter's respective circumference. A mixing wing of a mixing element and a mixing wing of the associated mixing element interengage and rotate past each other, while leaving a gap.

Abstract: In a screw element for the conditioning and/or processing of plastics or elastomers in a screw-type extruding machine having screw shafts drivable to rotate in the same direction and at least one pair of meshing screw elements, each screw element having a land of which the enveloping curve extends radially at a constant distance away from the respective shaft and, in the longitudinal direction, is of linear extension in parallel to the longitudinal axis of the shaft, a radially external screw land section near the housing running parallel to the inside wall of the housing with little play relative to the latter, for the purpose of moderate recirculation without stress points accompanied by strong axial and transverse mixing in a defined volume, it is provided that the enveloping curve encloses a blade land of reduced cross-sectional area referred to the enveloping curve, in that starting from the one axial end of the screw element and the first, in the circumferential direction external, end of the section, n

Abstract: A screw-type extrusion machine has a housing with at least one housing bore, in which a screw shaft is arranged. The housing has outer surfaces, which have a non-constant distance to the wall of the at least one bore. The outer surfaces are provided with heating elements. In order to attain an approximately constant temperature along the circumference of the wall of the at least one bore, heating elements of a different specific heating capacity are arranged sectionally on the outer surfaces of the housing, the heating elements being such formed that the heating temperature at the wall of the at least one bore is approximately constant.

Abstract: A process and apparatus for the finish grinding of cutting blades of a cutting tool head of a granulating device for thermoplastic material in which a grinding wheel is supported for rotation about a vertical axis with a grinding surface of the grinding wheel facing upwardly and the cutting blades of the cutting tool head rest on the grinding surface of the cutting tool head under the weight of the grinding wheel. The cutting tool head is free for vertical movement and is precisely aligned with the axis of rotation of the grinding wheel. The grinding wheel is driven by a motor around a vertical axis to grind the cutting surfaces of the cutting blades and produce precision ground surfaces on the blades which are aligned in a common plane.

Abstract: A throttle for the adjustment of the pressure of plastic material in screw extruders in which the throttle is a cylindrical plunger submerged in the melt flow in a melt channel. In order to eliminate dead spaces downstream of the throttle, the plunger is arranged in a symmetrical and displaceable manner in a rectangular melt channel and one or more through holes are provided in the plunger in the flow direction in the submerged region of the plunger.

Abstract: A process and apparatus for aligning the cutting surfaces of cutting blades of a granulating device, in which an abrasive plate is detachably connected to the granulating hood of the granulating device after disconnection of the hood from a die plate. The abrasive plate remains fixed and the cutting surfaces of the cutting blades are ground by rotating the cutting head so that the cutting surfaces will be aligned axially on the axis of rotation of the drive shaft of the cutting head and located in a common plane perpendicular to the axis of rotation. The grinding operation for alignment can be carried out in situ on the granulating device, or the granulating hood and cutting head can be removed from the granulating device and the grinding and alignment can be effected in a separate support.

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: An extruder for processing plastic material has a housing with a longitudinal bore in which an extruder screw is coaxially fitted for rotation around an axis of the screw to advance plastic material through the bore by threads on the screw. A plurality of throttling plungers are slidably supported in rectangular slots in the housing perpendicular to the axis of the screw. The throttling plungers define an inner throttling surface facing an outer thread-free region of the screw to form an annular throttle gap therewith. In order to avoid uncontrolled changes in the throttling system, the throttling surfaces are not concentric with the outer surface of the screw, so that the throttle gap has a width which varies progressively and symmetrically around the screw.

Abstract: A process and apparatus for the production of plastic material containing an additive in which the plastic material is supplied into a mixing tank to undergo vigorous mixing therein and the mixed plastic material is discharged by an extrusion screw at the bottom of the tank into a conveying cylinder in which the extrusion screw extends. The mixed plastic material is conveyed by the screw in the conveying cylinder for discharge of the plastic material at a discharge outlet. The plastic material is heated in the conveying cylinder to achieve melting of the plastic material and the additive is supplied to the melted plastic material within the conveying cylinder so that the additive is thoroughly mixed with the melted plastic material before discharge thereof at the discharge outlet.

Abstract: A screw kneader for a plastic material in which a pair of longitudinal screws are rotatably mounted in respective bores for conveying plastic material through the kneader. The screws have spaced portions for advancing the plastic material from an inlet region to an outlet region and between the spaced portions is a section with reversed threads opposing plastic flow to effect mixing of the plastic material. The threads of the intermediate section are provided with openings to permit passage of up to 20% of said plastic material in the direction of advance. Transfer elements with helical threads connect opposite ends of the threads in the intermediate section with the threads of the inlet and outlet regions. The transfer elements of the two screws mutually engage one another to strip plastic material from one another and from the walls of the bores.

Abstract: An extruder drivable for displacement by moving devices is provided for sewer pipe reconstruction and has a radial nozzle applying by extrusion a thermoplastic tube to the inside wall of a sewer pipe to be reconstructed. The thermoplastic tube is pressed against the inside wall by pressurized air and cooled down to form a lining pipe.

Abstract: A mixing and processing apparatus for plastic melt is equipped with a separately drivable gear pump as a delivery unit. In order to avoid material deposits between the mixing and processing apparatus and the delivery pump, the gear pump is directly mounted at the outlet end of the mixing and processing apparatus, such as an extruder, so that the plastic melt is directly fed axially into the suction space of the gear pump. Cleaning operations after shutdown or in the case of change of material are eliminated due to this direct transfer without dead space.