Open-loop apparatus for producing a controlled blend of polyol and blowing agent for use in the manufacture of polyurethane foam

An apparatus for preparing a blend of polyol and a blowing agent useful in the preparation of polyurethane type foam comprising:

• a) a first and a second conduit, said first conduit having the capacity to channel a blowing agent under pressure sufficient to maintain said blowing agent in a liquid state, said second conduit having the capacity to channel said polyol under a pressure sufficiently great to maintain said blowing agent in a liquid state, said first and second conduits channeling said blowing agent and said polyol through component parts as described herein to a variable speed kinetic mixer, said mixer having at least two entrance ports and at least one exit port;
• b) a first and a second variable flow positive displacement pump, said first displacement pump connected in-line with said first conduit, said second displacement pump connected in-line with said second conduit;
• c) a first and a second mass flow meter, said first mass flow meter connected in-line with said first displacement pump, said second mass flow meter connected in-line with said second displacement pump, said first and second mass flow meters further connected to said entrance ports of said mixer via said first and second conduits respectively;
• and
• d) a pressure regulator means connected to said at least one exit port of said mixer via a third conduit, said pressure regulator means having the capacity to maintain a fluid exiting said mixer at a pressure sufficient to maintain said blowing agent in a liquid state, and said pressure regulator means further having the capacity to control and maintain a pressure upstream to said first and second displacement pumps sufficient to maintain said blowing agent in said third conduit, said mixer, and said first and second conduits and downstream of said first and second variable displacement pumps in a liquid state.