Abstract: A valve plug in which excess metal has been removed, leaving only the necessary surfaces for providing sealing and a flow passage. The invention abandons the truncated cone shape of the prior art for a non-conical shape; the only portions of the plug which extend toward the surface of the valve body are those necessary to provide sealing contact. The plug uses a pipe-shaped flow conduit having a cross-sectional dimension to match the size of the valve body seat around the flow ports in the valve body. The flow conduit has walls of substantially uniform thickness, such that the exterior surface of the conduit is spaced from the interior surface of the valve body, except at the ends of the conduit. In two embodiments, arcuate plates extend laterally from the sides of the flow conduit; the plates prevent the passage of fluid through the valve body when rotated into position adjacent the flow ports. A cavity is defined between the plates and the exterior surface of the flow conduit.

Abstract: A valve lock assembly comprising a post member and a slide member, in which the post member is affixed to the valve stem of a valve and the side member can slide up and down around the post member, the slide member being so configured that it engages one or more of the stops on the valve to prevent rotation of the valve handle between the stops but, when slid upwardly, disengages from the stop and permits rotation of the valve handle.