| 摘要 |
486,124. Extruding rubber &c. RUBBER PRODUCERS RESEARCH ASSOCIATION, SCHIDROWITZ, P., and REDFARN, C. A. Dec. 3, 1936, No. 33174. [Class 87 (ii)] [Also in Group XI] Materials, such as chlorinated rubber or polystyrol, which expand on extrusion are shaped in apparatus comprising a cylindrical barrel 1 housing a screw 3 of uniform pitch and terminating in a nozzle 4, all of which are heated to a controlled temperature, and the cross-sectional areas of the space between the screw and the barrel, the zone in front of the screw, and the nozzle are all the same. The screw 3 is supported by a thrust bearing 5 and driven by a worm wheel 6. The barrel, screw, and nozzle are heated by electrical resistance elements 15, 16, 17 controlled by thermostats 27, 24, 28 respectively. Current is supplied to the element 16 by slip rings 18, 19 while the thermostat 24 is connected through mercury pick-ups 25, 26. The bearing 5 is kept cool by a water jacket 29. The material is supplied by a hopper 31 and is agitated by fingers 33. The nozzle 4 develops gradually from a circular to an oval cross-section and is flared at its outlet, the side walls being more flared than the upper and lower walls. The nozzle, barrel, and screw may be chromium plated to prevent sticking and the nozzle may also be lubricated by oil supplied through passages therein. In operation the screw is rotated at about 5 R.P.M. and the body and screw are maintained at temperatures of 350 and 347‹ F. respectively. The expanded product 50, Fig. 2, is shaped between polished metal bands 51, 52 which are heated bv electrical elements 57, 58 and cooled by elements 62. Specification 424,561 is referred to.
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