Patent ID: 7416096

Claim:
Apparatus for supplying liquid color to a plastic material processing machine, comprising: a. a sealable container for storing liquid color therewithin; b. a diaphragm pump within said container, the diaphragm pump: i. having a liquid color inlet to a first chamber bounded in part by said first side of the diaphragm proximate the container bottom, said diaphragm sealingly separating the pump into two interior chambers, said second side of said diaphragm sealingly bounding said second chamber from said first chamber and liquid color resident therein to maintain said second chamber liquid free; and comprising: ii. mechanical means contacting said diaphragm on said second side for reciprocatingly displacing said diaphragm into said first chamber to displace therefrom liquid color resident therein; iii. resilient means resident in said first chamber contacting said first side of said diaphragm to bias said diaphragm toward said second chamber when displaced by said mechanical means; and iv. means, positioned within the resilient means and being freely movable with respect thereto towards and away from the inlet, for closing the inlet to flow of liquid color from the first chamber back into the container; and c. a conduit connected to an outlet of said pump and passing through said container to deliver pumped liquid color from the first side of the diaphragm at the container exterior.