| 摘要 |
774,430. Extruding resins. NAAMLOOZE VENNOOTSCHAP ONDERZOEKINGSINSTITUUT RESEARCH. Nov. 24, 1954 [Dec. 31, 1953], No. 34100/54. Class 87(2). Relates to the manufacture of elongated objects from polyamides, polyesters and other artificial thermoplastic substances having a short melting range by pressing the molten substance through a duct 5, Fig. 1, into a cooled moulding device 25, the solidified object (bars, tubes &c.) being continuously drawn out of the moulding device as by rollers 28, 29. According to the invention a connecting tube 24 of poorly heat-conducting material is disposed between the duct and the moulding device. This tube keeps the molten substance hot until the substance enters the device, and when it enters it is cooled abruptly, a thick solid skin is formed on the interior of the device and the material does not stick in the device. The tube 24 may be made of " Syndanyo " (Registered Trade Mark-asbestos product). In the duct 5 are disposed also a pressure regulator 7 and a temperature regulator 20. The pressure regulator may be a gear pump having an overflow valve, Fig. 2, (not shown) or, Fig. 3, apparatus comprising two pistons 12, 19 the space between which is filled with a heatresistant grease, e.g. an organic polysiloxane. The molten substance passes from the righthand side of duct 5 to the left-hand side by way of bores 15, 13, 14 in piston 12 and its housing. When the pressure on the left increases, piston 12 is forced up against the resistance of a spring 16 and the bore 15 is partly closed, whereupon the pressure falls. The temperature regulator 20 includes a housing 21 through which flows temperature-regulating fluid. |
