Pressure relief valve

A pressure relief valve for cryogenic service, comprising:

• a base having a fluid inlet and a fluid outlet;
• a bonnet attached to the base, the base and the bonnet defining an internal cavity in fluid communication with the fluid inlet and the fluid outlet;
• a nozzle disposed within the fluid inlet and attached to the base, the nozzle including a nozzle groove radially formed on an exterior cylindrical surface of the nozzle, an outwardly disposed ledge having a lower ledge surface comprising a portion of an interior surface of the nozzle groove, and an upper ledge surface forming an annular seat of the nozzle;
• a disc holder disposed in the internal cavity;
• and
• a closure disc disposed within a proximal end of the disc holder, the closure disc comprising a substantially cylindrical body having an upper portion adapted to be received in the distal end of the disc holder and a lower portion having a lower closure surface,
• wherein the ledge of the nozzle is adapted to cause the annular seat to deflect upwardly and radially inwardly in response to a cryogenic thermal gradient applied across the ledge,
• wherein said cryogenic gradient created by a cryogenic temperature fluid flowing between the lower closure surface of the disc and the annular seat of the nozzle, and
• wherein, when subjected to the cryogenic thermal gradient, the upwardly and radially inwardly deflection of the annular seat places the annular seat in contact with the lower closure surface and substantially closes the valve.

A pressure relief valve for cryogenic service, comprising:

• a base having a fluid inlet and a fluid outlet;
• a bonnet attached to the base, the base and the bonnet defining an internal cavity in fluid communication with the fluid inlet and the fluid outlet;
• a nozzle disposed within the fluid inlet and attached to the base, the nozzle including a nozzle groove radially formed on an exterior cylindrical surface of the nozzle, an outwardly disposed ledge having a lower ledge surface comprising a portion of an exterior surface of the nozzle groove, and an upper ledge surface forming an annular seat of the nozzle, wherein the ledge of the nozzle is adapted to cause the annular seat to deflect upwardly and radially inwardly in response to a cryogenic thermal gradient applied across the ledge, said cryogenic gradient created by a cryogenic temperature fluid flowing between the lower closure surface of the disc and the annular seat of the nozzle;
• a disc holder disposed in the internal cavity;
• a closure disc disposed within a proximal end of the disc holder, the closure disc comprising a substantially cylindrical body having an upper portion adapted to be received in the distal end of the disc holder and a lower portion, the lower portion including a groove formed on an exterior radial surface of the cylindrical body, and an outwardly disposed lip having an upper surface comprising a portion of an interior surface of the groove and a lower closure surface proximate the annular seat of the nozzle,
• wherein the lip of the closure disc is adapted to cause the lower closure surface to deflect downwardly and radially inwardly relative to the annular seat in response to a cryogenic thermal gradient applied across the lip,
• wherein said cryogenic gradient created by a cryogenic temperature fluid flowing across the lower closure surface of the lip and the annular seat of the nozzle, and
• wherein, when the lip and ledge are subjected to the cryogenic thermal gradient, the downwardly and radially inwardly deflection of the lower closure surface and the upwardly and radially inwardly deflection of the annular seat places the lower closure surface in contact with the annular seat and substantially closes the valve.

A method for regulating a cryogenic process fluid, comprising:

• providing a pressure relief valve having:
• a base having a fluid inlet and a fluid outlet;
• a bonnet attached to the base, the base and the bonnet defining an internal cavity in fluid communication with the fluid inlet and the fluid outlet;
• a nozzle disposed within the fluid inlet and attached to the base, the nozzle having a substantially annular seat;
• a disc holder disposed in the internal cavity;
• and
• a closure disc disposed within a proximal end of the disc holder, the closure disc comprising a substantially cylindrical body having an upper portion adapted to be received in the distal end of the disc holder and a lower portion, the lower portion including a groove formed on an exterior radial surface of the cylindrical body and an outwardly disposed lip having an upper surface comprising a portion of an interior surface of the groove and a lower closure surface proximate the annular seat of the nozzle;
• exposing the fluid outlet to an ambient temperature;
• providing a cryogenic process fluid to the fluid inlet and through the nozzle, the cryogenic process fluid having a bulk temperature significantly less than the ambient temperature;
• opening the valve to allow fluid communication of the cryogenic process fluid from the fluid inlet to the fluid outlet;
• and
• closing the valve to prevent or substantially prevent fluid communication of the cryogenic process fluid from the fluid inlet to the fluid outlet,
• wherein the lip of the closure disc is adapted to cause the lower closure surface to deflect downwardly and radially inwardly relative to the annular seat in response to a cryogenic thermal gradient applied across the lip,
• wherein said cryogenic thermal gradient created by a cryogenic temperature fluid flowing between the lower closure surface of the lip and the annular seat of the nozzle, and
• wherein, when subjected to the cryogenic thermal gradient, the downwardly and radially inwardly deflection of the lower closure surface places the lower closure surface in contact with the annular seat and substantially closes the valve.

A method for regulating a cryogenic process fluid, comprising:

• providing a pressure relief valve having:
• a base having a fluid inlet and a fluid outlet;
• a bonnet attached to the base, the base and the bonnet defining an internal cavity in fluid communication with the fluid inlet and the fluid outlet;
• a nozzle disposed within the fluid inlet and attached to the base, the nozzle including a nozzle groove radially formed on an exterior cylindrical surface of the nozzle, an outwardly disposed ledge having a lower ledge surface comprising a portion of an interior surface of the nozzle groove, and an upper ledge surface forming an annular seat of the nozzle;
• a disc holder disposed in the internal cavity;
• a closure disc disposed within a proximal end of the disc holder, the closure disc comprising a substantially cylindrical body having an upper part adapted to be received in the distal end of the disc holder and a lower portion having a lower closure surface;
• exposing the fluid outlet to an ambient temperature;
• providing a cryogenic process fluid to the fluid inlet and through the nozzle, the cryogenic process fluid having a bulk temperature significantly less than the ambient temperature;
• opening the valve to allow fluid communication of the cryogenic process fluid from the fluid inlet to the fluid outlet;
• and
• closing the valve to prevent or substantially prevent fluid communication of the cryogenic process fluid from the fluid inlet to the fluid outlet,
• wherein the ledge of the nozzle is adapted to cause the annular seat to deflect upwardly and radially inwardly in response to a cryogenic thermal gradient applied across the ledge,
• wherein said cryogenic gradient created by a cryogenic temperature fluid flowing between the lower closure surface of the disc and the annular seat of the nozzle, and
• wherein, when subjected to the cryogenic thermal gradient, the upwardly and radially inwardly deflection of the annular seat places the annular seat in contact with the lower closure surface and substantially closes the valve.

A method for regulating a cryogenic process fluid, comprising:

• providing a pressure relief valve having:
• a base having a fluid inlet and a fluid outlet;
• a bonnet attached to the base, the base and the bonnet defining an internal cavity in fluid communication with the fluid inlet and the fluid outlet;
• a nozzle disposed within the fluid inlet and attached to the base, the nozzle having a substantially annular seat, a nozzle groove radially formed on an exterior cylindrical surface of the nozzle, and an outwardly disposed ledge having a lower ledge surface comprising a portion of an exterior surface of the nozzle groove and an upper ledge surface comprising the seat of the nozzle, wherein the ledge of the nozzle is adapted to cause the annular seat to deflect upwardly and radially inwardly in response to a cryogenic thermal gradient applied across the ledge,
• a disc holder disposed in the internal cavity;
• a closure disc disposed within a proximal end of the disc holder, the closure disc comprising a substantially cylindrical body having an upper portion adapted to be received in the distal end of the disc holder and a lower portion, the lower portion including a groove formed on an exterior radial surface of the cylindrical body and an outwardly disposed lip having an upper surface comprising a portion of an interior surface of the groove and a lower closure surface proximate the annular seat of the nozzle, wherein the lip of the closure disc is adapted to cause the lower closure surface to deflect downwardly and radially inwardly relative to the annular seat in response to a cryogenic thermal gradient applied across the lip;
• exposing the fluid outlet to an ambient temperature;
• providing a cryogenic process fluid to the fluid inlet and through the nozzle, the cryogenic process fluid having a bulk temperature significantly less than the ambient temperature;
• opening the valve to allow fluid communication of the cryogenic process fluid from the fluid inlet to the fluid outlet;
• creating a cryogenic thermal gradient in the lip and ledge by flowing cryogenic process fluid between the lower closure surface of the lip and the upper ledge surface of the nozzle;
• and
• closing the valve to prevent or substantially prevent fluid communication of the cryogenic process fluid from the fluid inlet to the fluid outlet,
• wherein, when the lip and ledge are subjected to the cryogenic thermal gradient, the downwardly and radially inwardly deflection of the lower closure surface and the upwardly and radially inwardly deflection of the annular seat places the lower closure surface in contact with the annular seat and substantially closes the valve.