Patent ID: 6851445

Claim:
A pressure relief device having: a housing including an inlet, an outlet, and an inner wall defining a bore connecting the inlet and the outlet, the bore providing a passage for flow of fluid between the inlet and the outlet; the inlet having an inlet diameter and the outlet having an outlet diameter, the inlet diameter being smaller than the outlet diameter, the inlet being in communication with a fluid under pressure in a vessel; the bore including an outlet portion with an outlet portion diameter greater than the inlet diameter, the outlet portion extending a first distance from the outlet toward the inlet, an inlet portion with a diameter substantially equal to the inlet diameter extending a second distance from the inlet toward the outlet, and a tapered portion extending between the inlet portion and the outlet portion, the inner wall in the tapered portion defining a substantially frusto-conical surface; a plug positioned in the bore and movable from a closed position, in which a flow of the fluid through the passage is blocked, to an open position, in which the flow of the fluid is permitted through the passage in response to a pressure differential between the inlet and the outlet; the plug including a tapered contact surface generally defining a conical surface, a contact portion of the conical surface being adapted to cooperate with the frusto-conical surface to define at least one void therebetween when the plug is in the closed position; a temperature-sensitive bonding material for bonding the contact portion to the frusto-conical surface, the bonding material being receivable in said at least one void; the bonding material being adapted to release the contact portion upon exposure of the bonding material to a predetermined temperature, such that the plug is movable relative to the frusto-conical surface upon release; the plug being maintained in the closed position by the bonding material until the bonding material is exposed to at least the predetermined temperature; the plug being movable to the open position by the fluid in response to the pressure differential upon the bonding material releasing the contact portion; and the plug including at least one duct leading from an inlet port on the conical surface to at least one exit port disposed in an outlet end of the plug disposed proximal to the outlet, said at least one exit port being positioned in the plug to register with the outlet, whereby upon the plug moving to the open position, the inlet is in communication with the outlet through said at least one duct.