Gulf Technologies International, L.c.

David G Ward

David Graham Hosie

Michael B Grayson

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. In the present configuration, when valve flow path pressure is greater than bonnet pressure, then seal bearing ring is urged against valve seat and effectively becomes part of the geometry of the valve seat. When bonnet pressure is greater than valve flow path pressure, then seal bearing ring is urged against seal seat and effectively becomes part of the geometry of the seal seat. The valve therefore effects a primary and secondary seal when the valve is closed so that even if the primary seal leaks, then the valve maintains its seal because the reversed differential across the secondary or downstream seat assembly causes the valve to maintain a gas tight seal.

Valve seat and method

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. The size of the operator is so small that it is comparable or the effectively the same as that of a valve having a simple straight-shaft valve operator.

Growing community of inventors

Houston, TX, United States of America

David G Ward