Buffer valve

Abstract

A buffer valve or compensator for use in a margarine mold system to permit continuous operation of a positive discharge pump in the system, such valve including a valve housing connected to a conduit section for a flow line on the discharge side of the pump, a central discharge tube in the housing, a blind bore in the discharge tube terminating at the inward end of the tube, lateral discharge ports in the discharge tube into the bore at the inward end thereof, an annular piston in the housing around the discharge tube movable between a first inward end position covering the discharge ports and a second outward end position uncovering the discharge ports, a stop member limiting the outward movement of the annular piston, and ports in the closed outward end of the housing for introducing air under pressure to bias the piston toward the inward end position. The buffer valve is connected between the positive displacement pump, a chiller, and the mold machine. A margarine recirculating line runs from the discharge tube of the valve through a remelt tank back to a storage tank connected with the pump. An air supply is connected with the housing air ports. The air system includes an exhaust valve which opens when the air supply is shut off allowing the buffer valve to open to recirculate margarine when the mold machine is cycling from finishing filling one mold to starting filling the next mold.