Patent ID: 7426936
Filing Date: 2008-09-23
Classification: F16J,F16K,Y10T

Abstract:
1. A stem sealing system for preventing leakage of a fluid in a valve housing having a movable stem, the stem sealing system comprising: a first set of dynamic seals engaging the stem; a second set of dynamic seals, the second set of dynamic seals engaging the stem and in spaced relation to the first set of dynamic seals; an auxiliary barrier fluid chamber surrounding the shaft and interposed between the first set of dynamic seals and the second set of dynamic seals, the auxiliary barrier fluid chamber being substantially free of barrier fluid during normal operation; and a barrier fluid indicator having a load member in a primary barrier fluid chamber, a first face of the load member exposed to pressure in the auxiliary baffler fluid chamber, a second face of the load member exposed to a barrier fluid contained between two seals in the first set of dynamic seals and inhibited from fluid communication with the auxiliary barrier fluid chamber by a dynamic seal in the first set of dynamic seals, the load member adapted to pressurize the barrier fluid based on the pressure in the auxiliary barrier fluid chamber.