The present disclosure provides a hydraulically controlled pressure relief valve without needing a hydraulic power unit. The valve maintains the accuracy of a hydraulically controlled valve by providing a self-contained closed hydraulic system built into the pressure relief valve. For safety, the valve can be kept open to call attention to the cause of the pressure relief valve activation, yet be easily reinstated into full service without replacing expendable components such as shear pins and rupture pins. The invention offers a pressure relief valve with accuracy, cost, and ease of use.

A pressure relief valve configured to vent a pressurized tank in the event of a fire is provided. The pressure relief valve includes a body, a vent passage, a plug and a latch. The vent passage is disposed through the body. The vent passage can be placed in fluid communication with an internal volume of a tank and with the atmosphere. The plug is moveably mounted in the vent passage. The latch has a blocking member disposed in contact with a control end of the plug in a first configuration and out of contact with the control end in a second configuration. The second configuration allows movement of the plug in the vent passage. One or both of a shape memory alloy wire and a trigger piston is configured to actuate the latch from the first to the second configuration. The shape memory alloy wire is configured to shorten when exposed to a temperature above a threshold temperature. The trigger piston moves, e.g., by a pressurized gas, in a trigger actuation passage to actuate the latch from the first configuration to the second configuration.

The present disclosure provides a hydraulically controlled pressure relief valve without needing a hydraulic power unit. The valve maintains the accuracy of a hydraulically controlled valve by providing a self-contained closed hydraulic system built into the pressure relief valve. For safety, the valve can be kept open to call attention to the cause of the pressure relief valve activation, yet be easily reinstated into full service without replacing expendable components such as shear pins and rupture pins. The invention offers a pressure relief valve with accuracy, cost, and ease of use.

A damped check valve having multi-pressure operation is provided. The check valve includes a liner with a poppet movable within the liner. The liner defines a flow passage aligned along a longitudinal axis defined by the liner. A biasing element is operably coupled between the poppet and the liner to bias a first flow face of the poppet against an annular seat. The first flow face is configured such that a first fluid pressure is required to move the poppet from the closed position to an open position wherein the poppet is unseated from the annular seat and a second fluid pressure is required to hold the poppet in the open position, the second pressure being less than the first pressure. There is a sufficient diametrical clearance between the poppet and the liner which allows for flow control at pressures which are less than the initial opening pressure.

A backflow prevention device includes a piston received in a device passage between an inlet port and outlet port. A relief port can fluidly communicate with a middle segment of the device passage. The piston is movable between a normal flow position in which the piston blocks fluid communication between the relief port and the middle segment of the device passage and a backflow position in which the piston allows fluid communication between the relief port and the middle segment of the device passage. The piston can move to the normal position in response to normal flow through the device passage from the inlet port toward the outlet port and configured to move to the backflow position in response to greater pressure in the middle segment than in the inlet port.

A battery housing includes a valve device for pressure equalization and for letting out a hot gas of a battery cell. The valve device has a valve seat in the form of a gas release opening in a housing wall of the battery housing and a valve body. The valve body closes the gas release opening when in a closed position, can be moved by a pressure-difference-induced internal pressure increase into a first open position in which the valve body reversibly opens the gas release opening to provide pressure equalization, and can be moved by a hot-gas-induced internal pressure increase into a second open position in which the valve body irreversibly opens the gas release opening to let out the hot gas.

In order to provide a pressure equalization apparatus (10) by means of which a pressure equalization can be brought about in the event of an overpressure—in particular, in an electrochemical system—and which is as simple as possible to produce, according to the invention, the pressure equalization apparatus comprises a main element (110), a sealing device (112), and a connection device (114) for connecting the main element and the sealing device, wherein the sealing device sealingly bears against the main element when the pressure equalization apparatus is in a closed state and is fixed relative to the main element by means of the connection device, and wherein a fixing connection between the main element and the sealing device which is formed thereby can be released in order to unblock a fluid connection between the interior of the pressure equalization apparatus and surroundings of the pressure equalization apparatus, and wherein the connection device comprises a spring element (150), the spring force of which acts in particular in a direction extending crosswise to an opening direction of the pressure equalization apparatus.

A pressure relief valve configured to vent a pressurized tank in the event of a fire is provided. The pressure relief valve includes a body, a vent passage, a plug and a latch. The vent passage is disposed through the body. The vent passage can be placed in fluid communication with an internal volume of a tank and with the atmosphere. The plug is moveably mounted in the vent passage. The latch has a blocking member disposed in contact with a control end of the plug in a first configuration and out of contact with the control end in a second configuration. The second configuration allows movement of the plug in the vent passage. One or both of a shape memory alloy wire and a trigger piston is configured to actuate the latch from the first to the second configuration. The shape memory alloy wire is configured to shorten when exposed to a temperature above a threshold temperature. The trigger piston moves, e.g., by a pressurized gas, in a trigger actuation passage to actuate the latch from the first configuration to the second configuration.

A pressure relief valve configured to vent a pressurized tank in the event of a fire is provided. The pressure relief valve includes a body, a vent passage, a plug and a latch. The vent passage is disposed through the body. The vent passage can be placed in fluid communication with an internal volume of a tank and with the atmosphere. The plug is moveably mounted in the vent passage. The latch has a blocking member disposed in contact with a control end of the plug in a first configuration and out of contact with the control end in a second configuration. The second configuration allows movement of the plug in the vent passage. One or both of a shape memory alloy wire and a trigger piston is configured to actuate the latch from the first to the second configuration. The shape memory alloy wire is configured to shorten when exposed to a temperature above a threshold temperature. The trigger piston moves, e.g., by a pressurized gas, in a trigger actuation passage to actuate the latch from the first configuration to the second configuration.

A backflow prevention device includes a piston received in a device passage between an inlet port and outlet port. A relief port can fluidly communicate with a middle segment of the device passage. The piston is movable between a normal flow position in which the piston blocks fluid communication between the relief port and the middle segment of the device passage and a backflow position in which the piston allows fluid communication between the relief port and the middle segment of the device passage. The piston can move to the normal position in response to normal flow through the device passage from the inlet port toward the outlet port and configured to move to the backflow position in response to greater pressure in the middle segment than in the inlet port.