| 摘要 |
1346095 Injection moulding; extrusion moulding R POHLMAN and G MENGES 19 April 1971 [14 March 1970] 23980/71 Heading B5A [Also in Divisions G3 and H4] A viscosity dependent process, e.g. one using molten plastics for the production of injection moulded parts, blown hollow parts, fibres, tubes or foils, is regulated in dependence on values of ultrasonic wave attenuation and/or wave velocity obtained by transmitting ultrasonic waves through a flowing viscous mass. In the Fig. 1 embodiment measurement head 8 provides ultrasonic waves passing transversely to the flow path of a plastics mass being conveyed to extruder nozzle 7 from hopper 4 by a worm conveyer 5 in a heated channel 6. Ultrasonic measurements are made in a throughtransmission or pulse-echo mode by means of pulse transmitter/receiver 9. Velocity and attenuation values derived by unit 10 are fed to data processor 11 which computes a viscosity value, compares this with a reference viscosity value, and supplies any difference signal to members 12 and 13 which regulate, e.g. the channel 6 heaters, or the supply of material to the extruder.
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