Pilot Assisted Check Valve for Low Pressure Applications

The oscillatory behavior can lead to seal wear, increased leakage, and the generation of foreign object debris (FOD), which is particularly problematic in high-reliability systems like spacecraft or cryogenic propulsion. The valve integrates a magnetic damping system into a conventional check valve architecture. Key components include a non-magnetic, electrically conductive poppet body (e.g., copper), a ferromagnetic sleeve (e.g., HIPERCO 50A) inside the poppet, and a set of Neodymium Iron Boron (NdFeB) magnetized rings arranged in alternating polarities around a non-magnetic valve body. A second ferromagnetic sleeve completes the magnetic circuit, concentrating magnetic flux through the poppet during motion. When the valve operates, the poppet moves in response to pressure differentials. As it travels through the magnetic field, eddy currents are induced in the conductive poppet body. These currents generate a magnetic field that opposes the motion of the poppet, providing velocity-proportional damping based on Lenz’s Law. This passive damping mechanism prevents oscillation and chatter without relying on fluid viscosity or mechanical contact, enabling smooth, reliable valve operation across a wide range of flow conditions. The system is tuned to achieve critical damping by balancing magnetic flux, poppet mass, and spring rate. This innovation offers significant advantages. In aerospace applications, the valve can be used in purge systems or cryogenic fluid lines to eliminate chatter, improving valve longevity and reducing FOD risk. In the oil and gas industry, it can enhance safety and reliability in high-pressure systems where valve failure could be catastrophic. Industrial processing systems benefit from reduced maintenance and improved flow stability. The valve’s passive, wear-free damping also lowers lifecycle costs and simplifies design integration, making it attractive for commercial licensing and deployment across multiple sectors. This technology is TRL 3 and is currently available for licensing.

NASA's technique simplifies the seat installation process by requiring less installation equipment, eliminating the need for unnecessary apparatus such as fasteners and retainers. Multiple seals can be installed simultaneously, saving both time and money. NASA has tested the long-term performance of a solenoid actuated valve with a seat that was fitted using the new installation technique. The valve was fabricated and tested to determine high-cycle and internal leakage performance for an inductive pulsed plasma thruster (IPPT) application for in-space propulsion. The valve demonstrated the capability to throttle the gas flow rate while maintaining low leakage rates of less than 10-3 standard cubic centimeters per second (sccss) of helium (He) at the beginning of the valves lifetime. The IPPT solenoid actuated valve test successfully reached 1 million cycles with desirable leakage performance, which is beyond traditional solenoid valve applications requirements. Future design iterations can further enhance the valve's life span and performance. The seat seal installation method is most applicable to small valve instruments that have a small orifice of 0.5 inches or less.

NASA's Magnetically Damped Check Valve invention is a damping technology for eliminating chatter in passive valves. Because valve failure in space missions can cause catastrophic failure, NASA sought to create a more reliable check valve damper. The new damper includes the attachment of a magnet to the poppet in a check valve to provide stabilizing forces that optimize flow and pressure conditions. Test results have proven that the Magnetically Damped Check Valve offers substantial benefits. The Magnetically Damped Check Valve works over a wide range of flow dynamics and eliminated chatter under all flow conditions tested, allowing valves to operate under various flow rates and pressures without a risk of degradation or total destruction from chatter. This technology could provide a more simple and cost-effective solution for valve manufacturers and system designers than solutions currently available in the market. Applications for the new valve include use in aerospace or industrial processes. NASA's damping technology was originally designed for check valves, but could also benefit pressure regulators, relief valves, shuttle valves, bellows sealed valves or other passive valves.

Without improvements in valve technologies, propellant and commodity losses will likely make long-duration space missions (e.g., to Mars) infeasible. Cryogenic valve leakage is often a result of misalignment and the seat seal not being perpendicular relative to the poppet. Conventional valve designs attempt to control alignment through tight tolerances across several mechanical interfaces, bolted or welded joints, machined part surfaces, etc. However, because such tight tolerances are difficult to maintain, leakage remains an issue. Traditional poppets are not self-aligning, and thus require large forces to “crush” the poppet and seat together in order to overcome misalignment and create a tight seal. In contrast, NASA’s poppet valve self-aligns the poppet to the valve seat to minimize leakage. Once the poppet and seat are precisely self-aligned, careful seat crush is provided. Owing to this unique design, the invention substantially reduces the energy required to make a tight seal – reducing size, weight, and power requirements relative to traditional valves. Testing at MSFC showed that NASA’s poppet reduces leakage rates of traditional aerospace cryogenic valves (~1000 SCIM) by three orders of magnitude, resulting in leakage rates suitable for long-duration space missions (~1 SCIM). NASA’s self-aligning poppet was originally targeted for aerospace cryogenic valve systems, especially for long-duration manned space missions – making the invention an attractive solution for aerospace valve vendors. The invention may also find use in the petrochemical or other industries that require sealing to prevent critical or hazardous chemicals from leaking into the environment. Generally, the invention may be suitable for any application requiring low-leak and/or long duration storage of expensive or limited resource commodities (e.g., cryogenic gases, natural gas, nuclear engines, etc).

Instead of looking to improve current valve designs, a new type of valve was conceived that not only addresses recurring failures but could operate at very high pressures and flow rates, while maintaining high reliability and longevity. The valve design is applicable for pressures ranging from 15-15,000+ psi, and incorporates a floating piston design, used for controlling a flow of a pressurized working fluid. The balanced, floating piston valve design has a wide range of potential applications in all sizes and pressure ranges. The extremely simple design and few parts makes the design inherently reliable, simple to manufacture, and easy to maintain. The valve concept works with soft or hard metal seats, and the closing force is easily adjustable so that any closing force desired can be created. The fact that no adjustment is required in the design, ensures valve performance throughout valve life and operation. This valve has many unique features and design advantages over conventional valve concepts: - The largest advantage is the elimination of the valve stem and any conventional actuator, reduces physical size and cost. - It is constructed with only 5 parts. - It eliminates the need for many seals, which reduces failure, downtime and maintenance while increasing reliability and seat life. - The flow path is always axially and radially symmetric, eliminating almost all of the flow induced thrust loads - even during transition from closed to open.