PLASTIC SERVICE VALVE

摘要

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. The actuator portion extends upwardly through the chamber upper portion, and a flange portion and a stem portion of the actuator extends above the valve body. The flange portion is spaced circumferentially around the stem portion and overlies in abutting relation an upper circumferential shoulder of the valve body portion. The flange portion bears on the upper shoulder so that impact forces applied to the actuator portion are transmitted away from the stem and plug portions and from the flange portion to the valve body portion for distribution throughout the valve body and to the piping system connected to the valve body. This arrangement prevents the localized concentration of impact forces on the valve actuator.