Pressure relief system with supply activated valve

#The present invention relates generally to pressurized fluid systems and more particularly, but not by way of limitation, to a pressure relief system which uses supply pressure to activate an actuator assembly to open or close a valve assembly.

#Pressurized fluid systems are typically provided with pressure relief capabilities to prevent the possibility of injury to humans and damage to equipment in the event of an overpressure situation. Such pressure relief systems often use a pressure responsive member that mechanically fails when subjected to a large increase in fluid pressure.

#A particularly advantageous pressure relief system uses a buckling pin arrangement such as taught by U.S. Pat. No. 4,724,857 issued to Taylor. In such a system, the pin is placed under compressive load along an axial length of the pin by the pressure of the fluid. A sufficient increase in fluid pressure above a nominal operational level causes the pin to buckle, or collapse, allowing a plunger or other mechanism to move to a position where a bypass path can be established to direct the fluid to reduce the pressure to a safe operational level.

#FIG. 1 is a partial cross-sectional view of a pressure relief system constructed in accordance with preferred embodiments of the present invention, with the system generally including a pressure response assembly, an actuator assembly, a clutch mechanism and a bypass valve assembly.

#FIG. 2 shows the system of FIG. 1 with the valve assembly in the open position to represent the response of the system to an overpressure situation.

#FIG. 3 is a cross-sectional view of the actuator assembly of the system of FIG. 1 in accordance with a preferred embodiment, with the actuator assembly placed in a normal, retracted position during steady state operation.

#Reference is now made to FIG. 1 which shows a pressure relief system 100 constructed in accordance with preferred embodiments of the present invention. The pressure relief system 100 (“system”) is preferably used as part of a larger pressurized fluid system in which a pressurized fluid is transported. The pressure relief system 100 is used to detect an overpressure situation with the fluid and to provide an emergency overpressure path for the fluid to reduce the possibility of injury to humans and damage to equipment.

#The system 100 is shown to generally include a pressure response assembly 102, an actuator assembly 104, a communication path 106 and a bypass valve assembly 108. The pressure response assembly 102 is shown to preferably comprise a buckling pin 110, although it is contemplated that other pressure responsive members can be used such as a shear pin or a frangible disk. The valve assembly 108 is shown to comprise a valve shaft 111 and a ball valve 112 with a central port 114, but other valve configurations can readily be used including a butterfly valve or a plug-type valve. The ball valve 112 is configured to be normally closed (NC), so that the system 100 operates to open the ball valve 112 to provide a bypass path for the fluid (as shown in FIG. 2). Alternatively, the ball valve 112 can be configured to be normally open (NO) so that the system operates to close the ball valve 112 to establish a shutoff path.

#The communication path 106 provides pressure communication from the pressure response assembly 102 to the actuator assembly 104 during an overpressure condition. As explained in greater detail below, pressurized fluid at a normal operational pressure is introduced into the pressure response assembly 102 such as through conduit 115. The fluid pressure applies an axial compressive force to the buckling pin 110 via piston 116. The piston 116 is configured to slide within a housing 118.