Thermal compensator valve for differential pressure devices

Claim 1

A thermal compensator flow valve for stabilizing the operating characteristics of a hydraulic differential pressure generating device over a broad temperature range comprising: a valve body having an inlet, an outlet and a flow passage between said inlet and outlet which is connected in parallel with a hydraulic differential generating device needing stabilization over a wide temperature range; a valve spool disposed in said flow passage having an orifice means insuring minimum fluid flow from said inlet to said outlet through said flow passage and arranged serially therein to decrease flow therethrough as said valve spool is driven unidirectionally in said flow passage, said valve spool also including port means to subsequently abruptly increase fluid flow through said flow passage as said valve spool is further driven unidirectionally in said flow passage, said valve spool arranged in said flow passage so inlet pressure will urge it in a direction to increase fluid flow through said flow passage through said orifice means; and a thermal responsive means having a temperature responsive element located in said flow passage downstream of valve spool adjacent to said outlet placing it in continuous communication with fluid flow through said flow valve, said temperature responsive element having a plunger engaging said valve spool operable to drive said valve spool unidirectionally against said inlet pressure acting said valve spool to first decrease fluid flow through said flow passage and subsequently abruptly increase fluid flow through said flow passage as the temperature of the fluid flowing through said flow passage continues to increase whereby the fluid flow through said flow passage will be inversely proportional to temperature up to a predetermined temperature.