US 4,056,122 AGranted

Fluid component recycling system in a plural component plastics molding machine

AssigneeThe Upjohn Company

InventorsAlfred Schlieckmann, Kurt Moser

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Abstract

A system is disclosed for a plural component plastics reaction injection molding machine which provides continuous supply and recycling of each of a plurality of liquid components between a mixing head and separate supply tanks for the respective liquid components. The system is designed to use a portion of the respective recycle conduits of the several components as supply conduits to the head, in parallel with the normal supply conduit to the head, during periods of reaction injection taking place in the mixing head, whereby to permit the employment of smaller diameter conduits in the aforesaid portions of the system without reducing the capacity of the molding system. Further economy is achieved by design of the aforesaid portions of the conduit systems to dispose either the supply or recycle conduit concentrically within the other.

Claims6

Dependent claims

In a system for supplying one of a plurality of fluids under pressure to a mixing head having a mixing chamber into which the fluids are injected to produce mixing thereof, a valve chamber associated with said head and an inlet valve in said valve chamber controlling admission of said one fluid from said valve chamber to said mixing chamber, a fluid reservoir for said one fluid, a supply line connecting said valve chamber to said reservoir, and pump means in said supply lines to deliver said fluid under pressure from said reservoir to said valve chamber, a return line connecting said valve chamber to said reservoir, and a stop cock in said return line, whereby fluid can be circulated by said pump from said reservoir through said supply line to said valve chamber and back through said return line to said reservoir when said stop cock is open;

the improvement which comprises
a by-pass line between said supply line and said return line in shunt connection with said inlet valve chamber, said by-pass line being located upstream of said stop cock;
said by-pass line affording resistance to flow therethrough and thereby causing division of fluid flow between said by-pass line and said valve chamber.

Dependencies are inferred from the claim text.