Rotary ball valve having seating rings

Abstract

A rotary ball valve comprises a housing formed of plastic material, the housing including a through passage. A plug formed of a plastic material is rotatably mounted in the housing and includes a ball-shaped gate having a passage which is alignable with the housing passage when the plug is open. A stem projects laterally of the housing passage to enable the plug to be manually rotated. A pair of seating rings formed of an anti-friction material encircle respective ends of the gate passage when the plug is open. The housing includes a pair of annular flanges disposed on opposite sides of the plug passage. Each flange contacts a back side of a respective one of the seating rings. Each flange is notched around its periphery to form a plurality of circumferentially spaced flange segments whose inner diameter is substantially the same as the diameter of the gate passage. The flange segments are arranged to urge the seating rings against the gate and are independently yieldable to enable the rings to conform to the shape of the periphery of the gate. Each seating ring includes an annular groove on its back side located radially outwardly of the flange segments. Each flange includes an annular ridge received in the groove and forming a fluid seal between the housing and the seating rings. A handle is provided which can be snapped onto the stem. A cap is thereafter inserted into the handle to prevent accidental removal of the handle.