Patent ID: 6988509

Claim:
A flow control device for stopping the flow of a gas when there is a break in the flowpath downstream of said device comprising: a housing having a valve body comprising a first end and a second end; an inlet port located in said first end of said housing for admitting a gas to said housing; an outlet port located in said second end of said housing for discharging gas from said housing; a valve chamber located in said housing having a first end and a second end, said first end of said valve chamber in communication with said inlet port and said second end of said valve chamber in communication with said outlet port; a piston located for reciprocating movement in said valve chamber, said piston having an inlet side and an outlet side; a first orifice on said piston for restricting flow from said inlet side of said piston to said outlet side of said piston; a base located in said second end of said valve chamber for receiving a probe, said base having holes to allow gas to flow out through the outlet port wherein said probe has a threaded end and said base has an internal threaded bore for receiving said threaded end of said probe, such that said threaded probe can be adjusted toward or away from said piston; and a spring for biasing said piston away from said probe to allow the flow of a gas from the inlet end to the outlet end, when differential pressure across piston exceeds spring load, said piston comes into contact with said probe, restricting flow until upstream pressure is removed.