Hermann Berstorff Maschinenbau Gmbh

Manfred Dienst

Wilhelm Brand

Dietmar Anders

Adolf Herbert

Siegfried Chszaniecki

Eberhard Uhland

Arnold Aschemann

Claus-Heinrich Wente

Norbert Rabiger

Gunther Henjes

A corrosion-resistant and wear resistant housing for a screw extruder having one or more axis-parallel bores, each of which accommodates a screw of the extruder. Support sleeves, which have a smaller internal diameter than the screw bore or bores and which guide the rotating screw or screws are disposed in the two end regions of the housing poritons, whereby the corrosion and wear caused by the material being extruded are primarily restricted to the support sleeves.

Wear-resistant housing for an extrusion device

A single or twin-screw device is used to incorporate additives in a thermoplastic plastics material melt. The or each barrel of the extruder includes a first feed aperture for the introduction of the melt and a second feed aperture downstream thereof for the introduction of the additives. A screw is mounted on a shaft in each barrel and includes a core and a helical flight. In the region of the second feed aperture, the flight is replaced by alternating disc members and spacer members mounted on the shaft. The diameter or major dimension of the disc members is approximately equal to the combined diameter of the screw core and its flight while the diameter of the spacer members is approximately equal to that of the screw core. The disc members have profiled downstream faces. The disc and spacing members increase mixing and consequently throughput in the region of the second feed aperture.

Extrusion device for incorporating additives

An extruder for degassing a thermoplastic plastics material melt comprises at least one screw mounted for rotation in a barrel. The barrel includes a first feed aperture for the introduction of the melt and a degassing port downstream thereof connectable to means for degassing the melt. The at least one screw is mounted on a shaft and has a helical flight. In the region of the port, the flight is replaced by alternating disc members and spacer members mounted on the shaft. The diameter or major dimension of the disc members corresponds substantially to the combined diameter of the screw core and its flight whilst the diameter of the spacer members corresponds to that of the screw core. The disc members have profiled downstream faces and the thickness of each disc member and each spacer member lies in the range of 0.1 to 0.5 times the diameter of the screw.

Degassing extruder

A process and an apparatus for continuously producing a rubber mixture. In the process, the constituents of the mixture are fed into a twin-screw extruder and are masticated and homogenized therein, with approximately 5% of the mixture being discharged and the remainder being recycled for further homogenization and for mixing with fresh batches of the constituents being fed into the extruder. The recycled mixture is circulated to and returned from a cooled, annular chamber dispersed exteriorly of the chamber of the twin-screw extruder, with the annular chamber having outflow and inflow passages communicating with the interior of the extruder.

Method and apparatus for the continuous manufacture of rubber or

A back-pressure bearing arrangement for a twin-screw extrusion device which prevents any back-pressure forces from affecting a gear arrangement used for driving the screws. By disposing the back-pressure bearings between the gear arrangement and the housing of the extrusion device and by providing a bearing plate, which is supported by adjustment bolts or tension rods, the bearings are frictionally disconnected from the gear arrangement housing and the back-pressure forces of the screw shafts are effectively prevented from adversely affecting the gear arrangement.

Back-pressure bearing arrangement for twin-screw extrusion devices

A method and apparatus for regulating a dose-charged twin-screw extrusion device so as to achieve optimum quantitative discharge of a material being extruded in an automatic manner. By monitoring the screw torque and the mass temperature and modifying the dosed supply of material and/or the screw speed in accordance with the monitored values, the optimum mode of operation is ensured for the extrusion device which fully utilizes the discharge capacity of the device without risking damage either to the extrusion device itself or to the material being extruded.

Method and apparatus for achieving optimum discharge from a twin-screw

In venting means for a screw extruder, particularly for thermo-plastics material, which venting means comprises a substantially vertical venting shaft communicating with the bore of a cylinder of the extruder and coupled to a low pressure source by a pipe, a pivotable flap which is moved from its normal position shown, when acted upon by plastics melt being extruded and rising in the shaft due to malfunction of the extruder, to cover the end of the pipe and prevent the melt passing into the pipe.

Venting means for screw extruders

A power branching transmission, having two parallel output shafts, each of which carries a rotationally rigidly connected ouptput drive pinion, the output drive pinions being axially offset with respect to one another and each meshing with a respective rotatable ring gear and with a respective central gear wheel disposed in the respective ring gear, a pair of driving pinions rotationally rigidly disposed on parallel drive shafts and each meshing with a respective one of the ring gears and a respective one of the central gear wheels, each of the ring gears and each of the central gear wheels having at least one coaxial race with at least one supporting roller disposed between the races and bracing the respective ring gear and associated central wheel with respect to one another. No housing is required, tooth forces of the ring gears and central gears being accommodated by the supporting rollers and not transmitted to the radial bearings of the input end output shafts.

Power branching transmission

Extruder and twin roller calendering plant for producing films or sheets of synthetic plastics or rubber material comprising a pair of calendering rollers mounted in a calender frame and an extruder nozzle head directed into the gap between the pair of calendering rollers, the calender frame being pivotally mounted such that it can be pivoted away from the extruder nozzle head to allow ready access to the extruder nozzle head. The calender frame may be pivotally mounted on the nozzle head and a counter balance weight and/or the drive motor for rollers can be mounted on an opposite side of the pivot to the rollers thereby to counter balance the weight of the rollers.

Extruder and twin roller calendering plant

A twin screw extruder comprising a cylinder having twin bores therein to receive the twin screw of the extruder and a circular casing with at least one passage to permit heating or cooling fluid to flow between the cylinder and the casing, in which the cylinder has a generally circular outside contour with a first set of grooves and a second set of grooves forming parts of said at least one passage, extending obliquely to the longitudinal axis of the cylinder and formed in the outer surface of the cylinder, the bottom walls of the grooves extending parallel to a plane which includes the two longitudinal axes of the twin bores with the first set of grooves lying on one side of said plane, and the second set of grooves lying on the other side of said plane, the inclination of said first set of grooves to said axis being opposite to the inclination of said second set of grooves to said axis, and the inside of the casing containing spaced recesses forming further parts of said at least one passage and, except for end ones of said recesses, each connecting one end of a respective one of the grooves of the first set of grooves to one end of a respective one of the grooves of the second set of grooves.

Growing community of inventors

Burgdorf, Germany

Manfred Dienst