CONTROL VALVE

摘要

An ANSI Leakage Class V control valve having consistent shut off characteristics with a reduced actuator force required to open and close the valve is provided. The trim arrangement (45) of the control valve includes a valve cage (48) having a multi-contoured inner surface. The multi-contoured inner surface can include a plurality of surfaces. The multi-contoured surface can include first (58), second (59), and third (60) perimeter surfaces, and a first transition surface (61) disposed between and coupling the first (58) and second (59) perimeter surfaces, and a second transition (62) surface disposed between and coupling the second (59) and third (60) perimeter surfaces. The valve also includes a valve plug (47) disposed at one end of a valve stem (56). The valve plug (47) controls the fluid flow through the valve. The valve plug (47) includes an opening (66) through the plug for equalizing pressure across the valve plug. An annular channel (64) is formed within a wall of the valve plug (47) and is sized to accommodate a sealing ring (63). The sealing ring (63) engages the second perimeter (59) surface to form a fluid seal that substantially hinders fluid leakage through the valve.