Plastic valve assembly

摘要

A molded polyethylene valve body has a conduit portion and an annular portion extending upwardly from the conduit portion. A passageway extends through the conduit portion for the conveyance of fluid. A valve seat is formed in the conduit portion by a metal sleeve that is molded in the valve body to prevent separation of the sleeve from the valve body during sustained pressures. O-rings positioned in grooves around the metal sleeve are compressed by the plastic material during the molding process to effect a seal between the sleeve and the plastic valve body. An annular rubber sleeve insert is vulcanized onto the inner diameter portion of the metal sleeve. A plastic valve disc is centrally positioned in the conduit portion within the periphery of the rubber sleeve insert and is arranged to sealingly engage the rubber sleeve insert when the valve is moved to the closed position. A metal stem extends through the annular portion of the valve body and is connected to the valve disc. The upper end of the metal valve stem is molded into an actuator. The actuator is sealingly connected to the annular portion of the valve body so as to maintain the actuator on the valve body in the event that the pressure seal between the valve disc and the valve body is destroyed.