Patent ID: 6454015
Filing Date: 2002-09-24
Classification: E21B,F16K

Abstract:
A gate valve comprising:a valve body having an upstream passage, a downstream passage, and a central chamber therein; a gate having a hole therein, the gate being linearly movable within the chamber between a closed position blocking flow through the passages and an open position in which the hole registers with the passages; upstream and downstream seat rings mounted in the chamber on opposite sides of the gate at intersections of the passages with the central chamber, each of the seat rings being located within a counterbore of one of the passages, the counterbore having a cylindrical wall and a base wall that is parallel to the gate, each of the seat rings having a cylindrical wall concentric with and spaced inward from the cylindrical wall of the counterbore and a base wall parallel to and spaced from the base wall of the counterbore, defining upstream and downstream seal ring cavities; a shearing edge located on a leading edge of a downstream side of the hole for shearing a wireline as the gate closes, the hole having an upstream side that has a leading edge that trails the shearing edge to cause shearing of the wireline only with the shearing edge on the downstream side; and a seal ring located within each of the seal rings cavities, each of the seal rings having a pair of legs extending from a base of the seal ring, with one of the legs being in sealing engagement with the cylindrical wall of the counterbore and the other of the legs being in sealing engagement with the cylindrical wall of the seat ring, the legs of the seal rings in the upstream seal ring cavity extending in an upstream direction, and the legs in the downstream seal cavity extending in an upstream direction.