Valve mechanism with replaceable seal rings

摘要

A gate valve mechanism is provided which is especially designed for use as a hot tap valve. The valve incorporates a fabricated valve body having internal seat rings with circular elastomer sealing elements disposed within circular sealed grooves formed therein. A slab gate member is movable between the seat members between open and closed positions and is positionable radially outwardly of the seal grooves to permit replacement of the elastomer seal members. The valve body structure is of minimal thickness to permit access to the seal members through the flow ports of the valve in order to permit seal replacement. The valve also incorporates an internal rotatable threaded drive stem which receives a drive nut interconnected with the gate to thus permit opening and closing movement of the gate member by simply rotating the valve stem. The seat rings accomplish venting of the seal groove to the valve chamber and metal internal sealing lands to prevent seal extrusion and damage upon valve opening and closing movement.