Dresser, Inc.

Thomas Henry Cunningham

Christopher Edward Wolfe

Azam Mihir Thatte

Henry William Boger

Xuele Qi

James Albert Stares

Nuo Sheng

A gap control device that works with a plug on a valve assembly for use in high-temperature applications. The plug may include two parts and a compressible seal that, when compressed, engages with an adjacent wall of a cylinder or 'cage' typical of a trim assembly. In one embodiment, the gap control device forms a hard stop that expands in response to high temperatures. This feature prevents excess over-travel between the two parts of the plug in the high-temperature applications so as to limit stress and wear on the compressible seal.

Regulating overtravel in bi-furcated plugs for use in valve assemblies

Embodiments of a seal element for use in a trim assembly that allow valves and, in particular, balance control valves to meet high-temperature and shut-off requirements. These embodiments can engage and disengage a cage element and a plug element of the trim assembly, thereby creating a seal that prevents leaks of working fluid that can compromise operation of the valve. In one embodiment, the seal element comprises an annular ring that circumscribes the outer periphery of the plug element. The annular ring can deflect in response movement of one part of the plug element relative to another part of the plug element. This deflection can cause the seal element to contact the cage element and the plug element in seal regions that are proximate to one another, and to the outer periphery of the plug element.

Device for sealing a valve

A trim assembly is provided with a cage with an internal surface and a cage port. A plug having an external surface is disposed in the cage and is operable between a closed position, a pressure balancing position and an open position. The trim assembly also includes a low friction flow restrictor disposed between the cage and the plug and a pressure energized seal disposed between the cage and the plug. A seal balancing volume defined by the internal surface of the cage, the external surface of the plug, the low friction flow restrictor and the pressure energized seal is provided. The seal balancing volume is in fluid communication with the cage port through the low friction flow restrictor and is maintained at a seal balancing volume pressure. The trim assembly further includes a pressure control assembly configured to vent the seal balancing volume.

Apparatus and method for reducing actuator thrust requirements in a control valve

An apparatus includes a cage and a main plug disposed in the cage. The main plug is movable between a main plug closed position and a main plug open position. A seal assembly disposed on the main plug, the seal assembly having a seal that is configured to contact the cage when the main plug is in the main plug closed position, and configured to reduce contact with the cage when a pressure differential across the seal is reduced. The apparatus includes a pressure balancing assembly movable between a closed position, an overtravel position and an open position. The pressure balancing assembly is configured to balance the pressure differential across the seal when in the overtravel and open position.

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North Easton, MA, United States of America

Thomas Henry Cunningham