Abstract: This invention relates to a novel polyether polyol blend having an overall hydroxyl number of 56 mg KOH/g to 140 mg KOH/g, an overall functionality of greater than 2, and an overall content of copolymerized oxyethylene of 20% to 40% by weight. These novel polyether polyol blends may also be in-situ formed novel polyether polyol blends. A process for preparing these novel polyether polyol blends is also disclosed. These novel polyether polyol blends are suitable for preparing viscoelastic flexible polyurethane foams, and in a process for preparing viscoelastic foams.

Abstract: The present invention relates to an improved uni-directional meter prover apparatus which includes a prover barrel having first and second ends, a piston disposed within the barrel which is propelled through the barrel by the flow of liquid therethrough, means for detecting the passage of the piston and comparing the volume of liquid displaced thereby with the volume of liquid measured by a meter being proved and means for transferring the piston from the second end of the prover barrel to the first end thereof. By the present invention, the first end of the prover barrel is positioned below the second end thereof and a piston transfer conduit is connected between the first and second ends of the prover barrel. First and second valve means are disposed within the transfer conduit for preventing liquid communication between the first and second ends of the prover barrel and for selectively retaining the piston therein.