Friedrich Theysohn Gmbh

Friedrich Theyson Gmbh

Ernst Kruger

Reinhard Klose

Helmut Habisohn

Wilhelm Herbach

A method of thermoplastifying a synthetic resin which is displaced by a worm in a worm housing. High-frequency energy is applied to the plastic in one or more regions along the path of the plastic in which there is no or little frictional heat generated by the interaction of the screw with the housing.

Method and apparatus for the plastifying of synthetic resins

The invention relates to an extrusion installation for elongate products, more particularly plastics tubes, having an extruder 1, followed by a water-cooled calibration sleeve 8 which can be acted upon by negative pressure and a wall thickness measuring device having an ultrasonic sensor 13. The characterizing feature of the invention is that the calibration sleeve 8 is preceded by a retaining device 10 by which the at least single ultrasonic sensor 13 is borne fixed or rotatable concentrically in relation to the elongate product with a predeterminable distance between its measuring head and the external surface of the elongate product 23, and the retaining device 10 has a releasable attachment sleeve 12 whose diameter so corresponds to the inlet side internal diameter of the calibration sleeve 8 that the attachment sleeve 12 performs a precalibration.

Wall thickness measuring device with calibration device

The invention relates to a control device for the mechanical or thermal adjustment of the nozzle (1) of an extruder for elongate products (2). In order to eliminate components for wall thickness fluctuations in the longitudinal direction of the elongate product (2) when determining the wall thickness of the elongate product (2) over its width or its periphery, a stationary ultrasonic measuring head (3) is provided in addition to a rotating or reversing ultrasonic measuring head (4). The measured values of the two measuring heads (3, 4) are so linked to one another in an evaluating unit (5) that it is possible to derive therefrom for the controller a correcting variable which leads to an adjustment of the nozzle (1) only if the wall thickness deviations discovered are due to an adjustment error at the nozzle (1).

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Georgsmarienhutte, Germany

Ernst Kruger