GB567805A - Improvements in apparatus for the moulding of thermo-plastic materials - Google Patents

Abstract

567,805. Feeding molten thermoplastic material into moulds. CALLENDER'S CABLE & CONSTRUCTION CO., Ltd., and RICHARDSON, A. B. F. G. June 11, 1943, No. 9442. [Class 87 (ii)] Apparatus for feeding thermoplastic material in a heated viscous-liquid state under high or low pressure into moulds comprises a steamheated reservoir 1 and a hydraulic press 9, both the reservoir and the press communicating with a pipe-line 14 which leads to the moulds. In operation, the valve 17 being closed, the material is introduced into the reservoir, the interior of which is under super-atmospheric nitrogen pressure, through an aperture normally closed by a plug 2, the plug is replaced, the reservoir is evacuated of gas through a valve 41, and vacuum is maintained during the melting period. The valve 41 is then closed, nitrogen under pressure is admitted to the reservoir from container 10, valve 17 is opened, and the material is thus forced through pipe 14 into a chamber 18, where it raises a hydraulic ram 24. The material passes on through the pipe 14 to nozzles 31, whence it may be admitted as required through valves 32 into moulds clamped to the nozzles by screw spindles 35. To exert a high pressure, the valve 17 is closed and the ram 24 is depressed to force material into the moulds. The ram may be raised, for cleaning the chamber 18, by a chain 45. A steam supply 5 heats the reservoir 1, the pipe 14, the ram 24, the chamber 18 and the nozzles 31. In a modification, the reservoir includes a screw conveyer, which may be used instead of or in conjunction with either the ram or the gas pressure.