Abstract: A valve includes a molded plastic body portion having an internal chamber with upper and lower portions. Fittings connect the valve to conduits of a piping system. A valve seat surrounds inlet and outlet openings in the chamber lower portion. A plastic plug member is rotatably positioned in the valve seat. The plug member is a molded unitary element. The valve body portion and plug member have a substantially uniform wall thickness throughout. The plug member includes an integral plug portion and an actuator portion which facilitates ease of disassembly of the valve for repair. The plug portion has a flow passage which communicates with the inlet and outlet openings in the valve seat and is rotatable between open and closed valve positions. Seals retained on the plug portion engage the valve seat in the closed position. The actuator portion includes shearable stops which permit 360.degree. rotational operation of the plug member upon failure of the stops under excessive torque.

Abstract: 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.