Windmoller Holscher

Windmoeller and Hoelscher

Richard Saatkamp

Dieter Borgmann

Hans-Udo Beckmann

Rudolf Peters

Werner Feistkorn

Christof Herschbach

The invention concerns a process and a device for the recognition of screws used in extruders or metering devices. In order to create a process that excludes the possibility that mixtures of granulates or powders with incorrect mixing ratios occur through installation of inappropriate screw shafts in metering screws, the screws are coded and the code is electronically identifiable.

Process and device for the recognition of screws used in extruders or

A procedure for feeding plastic granulate into the intake opening of a plastic extruder with a storage tank, and with an intermediate storage tank resting on a weighing device. In the procedure, the specified quantity by weight of material processed for the particular batch is determined by the rotations of the extruder screw In order to specify a procedure in which the recipe-, or batch-, change times is considerably shortened and plastic granulate is conserved, it is provided that the intermediate storage tank is filled through opening of the storage tank discharge with a specific quantity by weight of plastic granulate, and the storage tank is filled with its constant fill quantity after re-closure of its discharge, when the sum of the weight of the fill of both storage tanks corresponds to the remaining quantity by weight to be processed by the extruder, and that the conveyance of plastic material into the storage tank is discontinued, and the storage tank discharge is opened one or more times, until she quantity stored in it has entered into the intermediate storage tank.

Procedure for feeding plastic granulate into the intake opening of a

A process of determining the rate at which plastic granules are received by an extruder form a feed container having an outlet which opens into the inlet of the extruder, in which process granules are continuously fed to a supply container and consecutive charges of granules are intermittently fed to the feed container, the feed container is weighed before or at the beginning of or after or at the end of its filling operation, the time is measured which between the filling operations is required to withdraw the material in the amount which has been determined by the weighing operations, and the flow rate of the material is calculated from the amounts of material which have been received from the feed container in the measured intervals of time. A uniform feeding of material into the extruder will be ensured if granules and marginal strip material are supplied to the cyclone like container. The supply container is substantially used only as a mixing container and opens into a charge-holding container, which is provided between the supply container and the feed container. The granules of at least one component thereof and recycled marginal strips are continuously fed to the supply container. The feed container and the charge-holding container are weighed in intervals of time, and the feed rate of the granules of the at least one component is correspondingly increased or reduced when the measured total weight of the feed container and of the charge-holding container differs from a predetermined desired weight.

Process and apparatus for determining the rate at which material is

A method of regulation of the charging of the feed hopper of an extruder with plastic granules, where it is necessary to supply the material in an amount such that the average level in the container or hopper remains constant with the least possible fluctuation despite the continual, and as a rule, uninterrupted removal of material from the container in the case of which, despite uninterrupted removal of material, the average level in the hopper or other container is maintained and is subject to the least possible fluctuation.

Method and apparatus for regulating the level of a mixture of flowable

A method is described in which the operative condition of the cooling sections of a slot die for making flat films of thermoplastic material, or of an annular die of a blow molding extruder for making tubular films from synthetic thermoplastics, is tested. The cooling sections are provided with lines for supplying and discharging cooling air and the lines for supplying cooling air are connected, as required, to a central cooling air feed line, which is under superatmospheric pressure, by solenoid valves controlled by an electronic computer. In one embodiment of the invention, a testing program is performed in which the cooling air feed line is disconnected by a shut-off valve from the branch lines leading to respective solenoid valves when the latter are closed. A pressure detector disposed in the cooling air feed line is then used to measure the pressure and the pressure drop which occurs in the cooling air feed line upon the opening of the solenoid valve associated with the first cooling section that is to be tested. An error signal is generated when the pressure and the measured pressure drop do not correspond to values which are typically obtained in case of proper operations of the cooling air feed line and of the cooling section being tested. All cooling sections are subsequently tested, in succession, by closing all solenoid valves and the shut-off valve and opening only the solenoid valve associated with the cooling section to be tested during the testing interval.

Method of testing the operative condition of dies provided with cooling

Load resistors connected in parallel in a heating circuit having switches operable to connect and disconnect the resistors from a common supply line for heating a plurality of zones to maintain predetermined temperatures therein, are tested by disconnecting all of the load resistors from the supply line to begin a testing operation. Any current conducted when all load resistors are disconnected from the supply line is measured, after which the load resistors are then individually and successively reconnected to the supply line. The current then conducted from the supply line in succession to the load resistors is measured and compared with reference values of current through the load resistors when functioning properly.

Method of testing the function of load resistors connected in parallel

Apparatus for slitting a web (50) into narrower webs or strips comprises a plurality of cutters (45, 46), which are movable into engagement with the web to be slit and are carried by cutter holders (4), which are adjustable transversely to the web by positioning means (7). The cutter holders (4) are freely slidably mounted on a common track (2, 3) and are adapted to be fixed in position on said track by clamping or detent means (21, 22), which are adapted to be released by a control device (62). A feeder (7) is provided, which is parallel to the track (2, 3). The cutter holders (4) are adapted to be clamped or to be resiliently locked to said feeder under the control of a control device (62) so as to permit the cutter holders (4) to be displaced by the feeder to their desired positions.

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Lengerich, Germany

Richard Saatkamp