Spring biased safety valve

Claim 2

A normally open flow safety valve having a closed flow position in the presence of one of two predetermined conditions, said valve comprising a housing having an inlet and an outlet and a bore connecting the inlet and outlet for fluid flow therethrough, an outlet closure member mounted in said bore upstream of the outlet, resilient means normally urging said closure member upstream away from the outlet to an open flow position, said closure member being movable from the first normally open flow position to a second closed flow position in response to a fluid pressure differential condition between the inlet and outlet sufficient to urge said closure member downstream against said resilient means, downstream urging means mounted in said bore upstream of said closure member and coacting therewith to urge said closure member downstream to the closed flow position, temperature responsive means mounted in said housing and projecting radially inwardly into said bore to engage said urging means to prevent downstream movement thereof, said temperature responsive means being movable radially outwardly by said urging means in the presence of a predetermined temperature wherein said urging means urges said closure member downstream against said resilient means to the closed flow position.

Claim 3

A safety valve as set forth in claim 1 in which said closure member is a ball and said resilient means is a spring and further comprising a guide mounted in said bore, said guide forming a raceway for movement of said ball therealong.

Claim 4

The valve as set forth in claim 2 in which said downstream urging means is a second ball mounted in said raceway upstream from said first ball, a second spring biasing said second ball downstream into engagement with said first ball, said second spring having a greater strength than the spring acting on said first ball, said temperature responsive means engaging said second ball wherein said second ball is released for movement downstream to urge said first ball into sealing engagement with said outlet in response to said predetermined temperature.

Claim 5

A valve as set forth in claim 3 in which said temperature responsive means comprises a nut threadably secured in said housing, said nut being formed with a bore from one end to adjacent the other end, fusible plugs mounted in said nut bore at said other end, a pin slidably mounted in said nut bore and engaging said fusible plugs at one end, the other end of said pin engaging said second ball to restrict the downstream movement of said ball, said plugs being meltable at said predetermined temperature wherein said pin is urged radially outwardly along said nut bore by the force of said second spring acting on said second ball wherein said second ball can be urged downstream when said pin has moved radially outwardly along said nut bore a sufficient distance.

Claim 6

A safety valve operational in response to one of two predetermined conditions comprising a housing having an inlet, a bore in communication with the inlet, a guide mounted in said bore, said guide having parallel arms extending along said bore, said arms having upturned edges to form a raceway along said bore, a ball mounted for movement along said raceway, an end cap having a bore therethrough, means mounting said end cap to said housing to form the valve outlet, said end cap being formed with a valve seat surface at the inward edge thereof and terminating in said end cap bore, resilient means mounted in said end cap bore engaging said ball and urging said ball upstream along said raceway away from said valve seat surface wherein said valve is in the open condition for flow and whereby said ball is urged downstream to overcome the resistance of said resilient means in response to a predetermined pressure differential condition between the inlet and outlet sufficient to urge said ball downstream against said resilient means, downstream urging means mounted in said guide upstream of said first ball to urge said ball downstream into seating engagement with said valve seat surface, and temperature responsive means mounted in said housing and projecting radially inwardly to engage said urging means to prevent downstream movement thereof, said temperature responsive means being movable radially outwardly by said urging means in the presence of a predetermined temperature wherein said urging means urges said ball into engagement with said valve seat surface in response to said predetermined external temperature.

Claim 7

A safety valve operational in response to one of two predetermined conditions comprising a housing having an inlet, a bore in communication with the inlet, a guide mounted in said bore, said guide having parallel arms extending along said bore, said arms having upturned edges to form a raceway along said bore, a ball mounted for movement along said raceway, an end cap having a bore therethrough, means mounting said end cap to said housing to form the valve outlet, said end cap being formed with a valve seat surface at the inward edge thereof and terminating in said end cap bore, resilient means mounted in said end cap bore engaging said ball and urging said ball upstream along said raceway away from said valve seat surface wherein said valve is in the open condition for flow and whereby said ball is urged downstream to overcome the resistance of said resilient means in response to a predetermined pressure differential condition between the inlet and outlet sufficient to urge said ball downstream against said resilient means, downstream urging means mounted in said guide upstream of said first ball to urge said ball downstream into seating engagement with said valve seat surface, and temperature responsive means mounted in said housing and projecting radially inwardly to engage said urging means to prevent downstream movement thereof, said temperature responsive means being movable radially outwardly by said urging means in the presence of a predetermined temperature wherein said urging means urges said ball into engagement with said valve seat surface in response to said predetermined external temperature.

Claim 8

A valve as set forth in claim 5 further comprising abutment means formed in the end cap bore between said valve seat surface and outlet end and against which said resilient means acts.

Claim 9

A valve as set forth in claim 5 in which said urging means comprises a second ball mounted in said raceway upstream of said first ball and a spring mounted upstream of said second ball and urging said second ball downstream with a force greater than that of said resilient means.

Claim 10

A valve as set forth in claim 7 in which said temperature responsive means comprises a nut threadably secured in said housing, said nut having a bore from one end to adjacent the other end, a fusible plug mounted in said nut bore at said other end, an elongated pin extending inwardly from said nut bore and into restraining engagement with said second ball, said pin being slidingly mounted in said nut bore wherein said pin is held in engagement with said second ball when the external atmosphere is below said predetermined temperature.

Claim 11

The valve as set forth in claim 8 further comprising sealing means mounted in said nut in sealing engagement with said pin wherein fluid is prevented from flowing into said nut bore.