Pressure indicator and surge control device

Claim 1

An apparatus connectable to a fluid system in which fluid at a relatively high pressure is supplied to a component of the fluid system and discharged therefrom at a relatively low pressure, said apparatus comprising: an indicator device including a housing, a pressure-responsive member mounted for movement in said housing between first and second positions and resilient means for urging said pressureresponsive member toward said first position thereof, said pressure-responsive member having first and second generally opposed faces; said housing defining a seat, said resilient means urging said first face of said pressure-responsive member into engagement with said seat, a portion of the area of said first face lying radially outwardly of said seat whereby the effective area of said first face is increased when said first face is moved out of engagement with said seat; said indicator device including means defining a leakage passage extending from said first face to said second face of said pressure-responsive member; said housing having an opening for providing communication between said second face of said pressure-responsive member and the low-pressure side of the component whereby the second face of said pressure responsive member is exposable to fluid at the relatively low pressure; passage means for providing a flow path between said first face of said pressure responsive member and the high-pressure side of the component, said pressure-responsive member being movable by the relatively high-pressure fluid from said first portion toward said second position against the force of the resilient means in response to a pressure differential across the component of a first predetermined magnitude; and surge control means at least partially in said passage means responsive to predetermined pressure conditions for increasing the resistance to flow of the fluid through said surge control means to said first face of said pressure-responsive member without completely blocking flow of fluid through the surge control means whereby the movement of the pressure-responsive member to said second position is retarded.

Claim 2

An apparatus connectable to a fluid system in which fluid at a relatively high pressure is supplied to a component of the fluid system and discharged therefrom at a relatively low pressure, said apparatus comprising: an indicator device including a housing, a pressure-responsive member mounted for movement in said housing between first and second positions and resilient means for urging said pressureresponsive member toward said first position thereof, said pressure-responsive member having first and second generally opposed faces; said housing defining a seat, said resilient means urging said first face of said pressure-responsive member into engagement with said seat, a portion of the area of said first face lying radially outwardly of said seat whereby the effective area of said first face is increased when said first face is moved out of engagement with said seat; said indicator device including means defining a leakage passage extending from said first face to said second face of said pressure-responsive member; said housing having an opening for providing communication between said second face of said pressure-responsive member and the low-pressure side of the component whereby the second face of said pressure responsive member is exposable to fluid at the relatively low pressure; passage means for providing a flow path between said first face of said pressure responsive member and the high-pressure side of the component, said pressure-responsive member being movable by the relatively high-pressure fluid from said first portion toward said second position against the force of the resilient means in response to a pressure differential across the component of a first predetermined magnitude; and surge control means at least partially in said passage means responsive to predetermined pressure conditions for increasing the resistance to flow of the fluid through said surge control means to said first face of said pressure-responsive member without completely blocking flow of fluid through the surge control means whereby the movement of the pressure-responsive member to said second position is retarded.

Claim 6

An apparatus connectable to a source of fluid at first and second pressure zones wherein the pressure at the first pressure zone may exceed the pressure at the second pressure zone, said apparatus comprising: an indicator device including a housing, a pressure-responsive piston in said housing movable between first and second positions, and yieldable means for urging said pressure-responsive piston to said first position, said pressure-responsive piston having first and second faces; said piston being spaced from the housing to define a fluid leakage path around said piston; first passage means for providing a fluid flow passage between the first pressure zone and the first face of the pressure-responsive piston of the indicator device whereby fluid from the first pressure zone can be supplied second passage means for providing a fluid flow passage between the second pressure zone and the second face of the pressure-responsive piston of the indicator device whereby fluid from the second pressure zone can be supplied to the indicator device; a surge control device at least partially in the first passage means intermediate the first pressure zone and the first face of the pressure-responsive member of the indicator device; and said surge control device including means defining first and second capillaries providing first and second flow paths, respectively, with said flow paths extending in parallel through said surge control device to said first face and pressure-responsive valve means for closing said first capillary.

Claim 7

An apparatus connectable to a source of fluid at first and second pressure zones wherein the pressure at the first pressure zone may exceed the pressure at the second pressure zone, said apparatus comprising: an indicator device including a housing, a pressure-responsive piston in said housing movable between first and second positions, and yieldable means for urging said pressure-responsive piston to said first position, said pressure-responsive piston having first and second faces; said piston being spaced from the housing to define a fluid leakage path around said piston; first passage means for providing a fluid flow passage between the first pressure zone and the first face of the pressure-responsive piston of the indicator device whereby fluid from the first pressure zone can be supplied second passage means for providing a fluid flow passage between the second pressure zone and the second face of the pressure-responsive piston of the indicator device whereby fluid from the second pressure zone can be supplied to the indicator device; a surge control device at least partially in the first passage means intermediate the first pressure zone and the first face of the pressure-responsive member of the indicator device; and said surge control device including means defining first and second capillaries providing first and second flow paths, respectively, with said flow paths extending in parallel through said surge control device to said first face and pressure-responsive valve means for closing said first capillary.