Patent ID: 8490885

Claim:
A thermally actuated valve with integrated pressure relief comprising: a housing defining an inlet, an outlet, and a cavity having a longitudinal axis disposed between and in fluid communication with said inlet and outlet, said housing defining a first bore aligned with said longitudinal axis and in fluid communication with said outlet; an actuator disposed in said cavity and having a variable axial length between a first end and a second end, said actuator responsive to changes in temperature in said cavity to generate an axial force F 1 acting to increase the axial length of said actuator in response to an increase in temperature from a first temperature T 1 to a second temperature T 2 , said actuator first end being fixed with respect to said housing and said actuator second end including an axially extending plunger movable with respect to said housing in response to changes in said axial force F 1 , said plunger aligned with and extending into said first bore at temperatures above T 2 , said plunger defining a pressure relief fluid flow path extending between said cavity and said outlet; a pressure sensitive valve arranged in said pressure relief fluid flow path, said pressure sensitive valve having a closed position preventing fluid communication between said cavity and said outlet at cavity pressures below a predetermined pressure P and an open position allowing fluid communication between said cavity and said outlet at cavity pressures above said predetermined pressure P; a seal between said plunger and said first bore, said seal arranged to prevent fluid communication between said cavity and said outlet when said plunger is received in said bore; a return member engaged with said actuator to bias the actuator and plunger away from said bore with a bias force F 2 opposed to said axial force F 1 , wherein said pressure sensitive valve is contained within and moves with said plunger, said axial force F 1 overcomes said bias force F 2 to extend said plunger into said bore at temperatures above T 2 and said bias force F 2 acts to reduce the axial length of said actuator at temperatures below T 2 to an axial length insufficient to project said plunger into said bore, resulting in fluid communication between said inlet and said outlet, said fluid communication having a flow rate which varies with the axial length of said actuator.