Temperature modulated pressure regulating valve

Claim 1

A thermally responsive pneumatic pressure regulating valve for providing a regulated pressure head inversely proportional to a temperature signal, said valve having a body including a supply chamber and a regulating chamber spaced from each other, an inlet port communicating with said supply chamber adapted for connection to a source of fluid pressure, an outlet port communicating with said regulating chamber adapted for connection to control apparatus, and a vent port spaced from said outlet port; a temperature sensor mounted in said body having a portion extending externally thereof in communication with said temperature signal and including a movable portion disposed within said supply chamber, said movable portion being adapted for extensile movement in response to temperature rise; an annular balance piston slidably mounted within said body between said outlet port and said vent port including a central aperture, one face of said piston being adjacent said outlet port defining one end of said regulating chamber, said one piston face including a first annular valve seat surrounding said central aperture; a regulating spring disposed between an opposite face of said piston adjacent said vent port and a shoulder formed in said body adjacent said supply chamber, said regulating spring biasing said piston against the force of a regulated pressure in said regulating chamber; an elongated hollow slideable plunger mounted in said body extending through the central apertured portion of said piston, said plunger having a first end portion thereof disposed within said supply chamber engageable with said movable portion of said temperature sensor, said first end portion including a passage communicating the interior of said plunger with said supply chamber, said plunger having a second end portion thereof disposed within said regulating chamber including a second annular valve seat defined thereon; and a movable pilot member disposed in said regulating chamber having a flange portion including a first annular sealing surface adapted for engagement with said first annular valve seat of said piston and having a socket portion including a second annular sealing surface adapted for engagement with said second annular valve seat of said plunger, said pilot member being resiliently urged toward sealing engagement with said piston, being movable out of engagement with said first annular valve seat in response to extensile movement of said plunger for bleeding pressure fluid from said regulating chamber through said central aperture of said piston member, said second sealing surface being separated from said second valve seat in response to retractile movement of said plunger for admitting pressure fluid to said regulating chamber.