Abstract: Apparatus and methods are disclosed for a valve seat wherein the geometry of the seat is such that the resultant axial forces due to the differential between internal and external pressure across the valve seat result in a resultant axial force that urges the valve seat into sealing engagement with the plug or other type of closure member, regardless of the direction of the differential pressure. Thus the valve seat is urged against the closure member regardless of whether the line pressure or bonnet pressure is higher. In the same manner, a resultant axial force urges a seal seat of the preferred embodiment into sealing engagement with the valve body. An axially moveable seal bearing ring is positioned between the valve seat and the seal seat that alters the effective geometry of the seat elements when it moves between a first position and a second position. The seal bearing ring moves responsively to the direction of the differential pressure across the seat elements.

Abstract: The valve operator of the present invention provides an apparatus and method for reducing torque necessary for opening and closing a valve, such as a quarter-turn rotary valve. In the preferred embodiment, an outer handle adaptor has inner curved tracks that drive balls positioned in straight slots of a middle cylinder. As the balls move in the straight slots, they transfer torque energy to a valve shaft adaptor mounted within the middle cylinder and having outer curved threads that mesh with the balls. The pitch of the curved tracks of the outer handle differ from the pitch the curved tracks of the valve shaft adaptor to thereby effect a desired torque reduction ratio. The valve operator has relatively few components, at least three or more relatively rotatable components, preferably arranged in meshing configuration so as to effect a small size operator without the use of a gear box.