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: 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.

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 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 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: Dough processing method and apparatus in which a head machine has a dough divider for producing successive dough pieces, one after the other, and a conveyor for conveying the dough pieces from the dough divider to a subsequent treatment device A first drive motor drives the dough divider and the conveyor. The subsequent treatment device has a transport conveyor with dough cups for receiving the dough pieces from the conveyor of the head machine at a transfer station and for transporting the dough pieces in the subsequent treatment device A second drive motor drives the transport conveyor. A frequency convertor is connected to the first drive motor to control the speed of operation thereof based on a selected frequency from the frequency convertor.

Abstract: A granulating device for plastic compounds in which cutting knives of a cutting device face the die plate of a granulating head to form granules of plastic strings extruded from the die plate. The cutting knives are supported on a cutting shaft driven in rotation by a drive shaft of a drive motor. The cutting shaft is rotatably supported in fixed axial position in a housing. In order to obtain a planar parallel and central positioning of the cutting knives relative to the die plate, for example, due to thermal displacement, the housing and drive unit are guided together in a displaceable manner on guide shafts having first ends fixed to the granulating head and opposite ends which are vertically supported for universal pivotable movement in the manner of propped cantilever beams.

Abstract: A gambling device has a base plate (1') and attached to the latter a spring rod (2) to be set moving in bending oscillations. Several disks (15 to 18) are arranged on the latter. The lowermost disk is formed as a catch disk (18) to which pin-shaped spacers (21) and upwards protruding catching pins (22) are attached.

Abstract: A machine for dividing dough in which a dough supply unit delivers dough under pressure at an outlet end into dividing chambers of a rotatable carrier, the carrier having double measurement pistons in the dividing chambers for selectively delivering larger and smaller dough masses for a given stroke of the pistons. Each of the measurement pistons can be manually adjusted from outside the machine to be placed into first and second operational states in which, for a given stroke of the measurement piston respective larger and smaller volumes of dough mass are discharged from the machine. Each measurement piston includes an external piston slidable in a respective dividing chamber and an internal piston slidable in the external piston and the pistons are coupled for conjoint movement in the first operational state whereas in the second operational state, the external piston is fixed in the dividing chamber and the internal piston is slidable in the external piston.

Abstract: A continuous operation apparatus for fermenting dough products disposed on carriers which are conveyed stepwise through a fermenting chamber by vertical and horizontal conveyors. In order to obtain maximum space utilization and product density in the fermenting chamber with vibration-free and shock-fee transfer of the carriers, a vertical transport system is provided in which several vertical pairs of columns are employed to support the carriers at successive vertically spaced levels or stages and to stepwise transport the carriers vertically. One of the columns of each pair is rotatable while the other of the columns is rotatable and vertically displaceable. The pairs of columns are provided at each stage with horizontal projections for the support of the carriers. The carriers are transported stepwise by the vertically displaceable columns and successively transferred onto the rotatable columns.

Abstract: A rotor (2) surrounded by a strainer basket (3) is arranged vertically in a housing (1). Conveyor blades (7) arranged one above the other are distributed over the rotor (2) to convey plastic granules from a product inlet (14) arranged at the bottom of the housing to a discharge unit (15). A fan (19) is disposed in a discharge hood (16) and it has ejector blades (21) for assisting the radial discharge of the granules into unit (15). In order to change the residence time of the plastic granules in the dryer, a change in pressure is produced in the centrifugal dryer by replacing the fan with one having ejector blades whose outer diameter and/or length is different, the diameter of rotor (2) and its conveyor blades (7) being kept the same.