A magnetically retained pressure-relief valve enables quick-open on/off operation when overpressure is reached.
Inventors at NASA’s Kennedy Space Center have developed a magnetically retained, fast-response pressure relief valve that is designed to fully open at precise cracking pressures, and that operates in a fully open/fully closed manner. The use of a magnetically controlled relief valve, as opposed to a spring-based relief valve, enables quick-open on/off relief operation when overpressure is reached. This is due to the rapid decay of the magnetic field as the fluid medium pushes the valve poppet to an open position. Spring-based relief valves require increasing pressure and force to continually compress the spring and open the relief valve. This requirement greatly complicates the design of a system relief mechanism. A magnetic relief valve reduces these design complexities by eliminating the spring.
The innovation was developed for low-pressure pneumatic testing of a vacuum chamber in the Kennedy Cryogenics Test Laboratory. Standard relief valves that utilize mechanical springs did not function adequately at the low pressure (16 psi) required by the inventors during testing. The NASA valve eliminates the need for a spring by instead incorporating magnets to hold the poppet relief valve in the closed position. The use of magnets in a pressure relief valve exploits the exponential decay of the magnetic field between two magnets as they are separated. This leads to a faster-acting valve that does not require an increasing force to open the relief valve after cracking pressure has been surpassed, as is the case in standard pressure relief valves.
The relief valve mechanism is fully sealed and is isolated from the flow path of the fluid/gas media. This may lead to lower maintenance than is currently required for other pressure relief valves. Existing relief valve springs are exposed to corrosive environmental factors and system fluids, leading to deterioration that can cause changes in the cracking pressure.
Potential applications include pressure vessels, vacuum chambers, low-pressure systems, basic industrial systems, and gas and liquid systems.