Patent ID: 7353834

Claim:
A pressure regulator valve comprising: a valve seat separating a fluid flowpath into an upstream region and a downstream region; a valve closure member mounted on a valve stem, the valve stem operable to vary a separation between the valve seat and the valve closure member; a diaphragm mounted in a housing between a first interior region of the housing and a second interior region of the housing, the diaphragm including mobile portions responding to changes of pressure in one or both of the interior regions of the housing by changing position relative to the housing; a diaphragm stem attached to the diaphragm such that movement of the mobile portions of the diaphragm causes movement of the diaphragm stem; and a linkage mechanically coupling the diaphragm stem to the valve stem, wherein the diaphragm stem slidingly engages a diaphragm link of the linkage and the valve stem slidingly engages a seat link of the linkage; wherein the linkage includes at least four links, the links attached to each other at connection points, the linkage providing a mechanical advantage that increases as the valve stem is moved toward a closed position.