Patent ID: 6193213
Filing Date: 2001-02-27
Classification: F16K,Y10T

Abstract:
An instrumentation valve comprising:(a) a valve body having a fluid flow passage therethrough cooperatively arranged relative to a valve seat;(b) a valve element adapted to be seated against said valve seat and having first and second operative positions, one position opening said fluid flow passage through said valve body for fluid flow and the other position switching said fluid flow passage, said housing enclosing said valve element therein against said valve seat;(c) valve element spring providing a relatively fixed force, said spring bearing against said valve element to relatively urge said valve element into sealing engagement with said valve seat to enable fluid flow up to a selected pressure to flow through said fluid flow passage and past said valve seat without leakage;(d) a fluid pressure responsive, pressure receiving chamber adapted to be connected to a source of fluid, said chamber further including a movable link to provide a variable force to said valve element responsive to the fluid source pressure to variably load said valve element as a function of the pressure of the fluid to be switched; and(e) said movable link includes a limit restricting the variable force between upper and lower force values.