PROCEDURES AND SYSTEM FOR THE SPRITING OF ARTICLES UNDER THE USE OF A FLOW DUMPING COMPRESSION UNIT

摘要

A method of and apparatus for injection molding plastic articles. The apparatus includes a resin injection nozzle, a mold having an injection aperture and a mold cavity for receiving molten resin from the nozzle. The gas compression unit (37') includes a gas booster (58) which pressurizes a first charge of gas to the pressure setting of a pressure switch (71). The gas receiver (72) stores the first charge of pressurized gas at a pressure level within a predetermined range of pressures. A first fluid pressure reducing valve (74) reduces the pressure of the gas as it is communicated from the fluid receiver (72) to an orifice in the mold to an acceptable level for molding the article. A second fluid pressure reducing valve (79) allows a relatively low holding pressure in the article sufficient to complete the article and hold any thick sections of the article from sinking. The gas compression unit (37') is capable of servicing several injection molding machines and corresponding molds when a plurality of such first and second pressure reducing valves (74, 74', 74'', 79) are provided.