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We report on the development of a Micro-Electro-Mechanical Systems (MEMS) valve that is designed to meet the rigorous performance requirements for a variety of space applications, such as micropropulsion, in-situ chemical analysis of the planet, or micro-fluidics experiments in micro-gravity.
We developed a superfluid leak tight low temperature valve that can be activated by a magnetostrictive material.
Mission Research Corporation (MRC) in cooperation with the Jet Propulsion Laboratory (JPL) has developed a new small remote-controlled fluid valve.
Investigation of recent pyrovalve failures reveals timing of redundant initiator firings is crucial for reliable operation of pyrovalves. Simultaneous firing, i.e., within a very narrow time frame, was found to be the primary cause of the valve failing to operate. Testing of both single and dual initiators revealed important design characteristics affecting pyrovalve device performance. They include Primer Chamber Assembly (PCA) geometry and material properties, as well as operational effects on combustion product flow, and resulting energy transfer to the booster. The CONAX PCA design has evolved slowly over time undergoing incremental changes to correct known issues. These piecewise changes were verified by limited test, without a full understanding of the overall system impact or effect on margins. Adequate system performance margins may be adversely affected in existing or future systems incorporating a pyrovalve actuated by simultaneous firing of dual initiators.
A hollow spherical segment valve with an eccentric permits non-rubbing closure and provides a means for gas-cooling the seal. The design allows quick opening at high temperatures and discharge pressures.
Low-temperature chemical starting of combined jp-4 nitric acid propellant for low-thrust rocket engine using three-fluid propellant valve
Fast, accurate, multipressure measuring system, which employs a multiple port pressure scanning valve that connects a pressure transducer to many pressures, is described.
Two thin blades are incorporated into a valve which, when closed, form a sealed compartment in the shock-tube portion of a pipeline. When forced open by an actuator, gas flows through the system.
A pilot-operated relief valve which provides positive seating against leakage in cryogenic systems is described. The principal advantage is that the pilot poppet is unaffected by variations in control pressures in the pilot cavity, and results in a more accurate sensing of inlet pressure conditions.
Soft-seat poppet valve provides positive closure against fluid without damage to the seating surface on repeated cycling. It incorporates two compressible soft rings and a retaining ring of hard metal. Sealing is effected when the poppet seat is forced into intimate contact with a mating surface on one of the soft rings.
Shutoff and time delay valve, which incorporates a metering spool that moves at constant velocity under pneumatic pressure and spring compression, increases fluid-flow area at a uniform rate. Diaphragm areas, control cavity volume, and bleed-orifice size may be varied to give any desired combination of time delay and spool travel time.
Two porting rings, one within the other, control gas or liquid flow by using seal buttons as the sliding valve closers. Multiporting within the ring allows close control of the flow by the slight rotation of the outer porting ring.
Hard anodic coating provides a smooth wear resistant value seating surface on a cast aluminum alloy valve body. Vacuum impregnation with a thermosetting monomer, diallyl phthalate, seals the pores on the coating to prevent galvanic corrosion.
Four-terminal network forms a bidirectional valve which will switch or alternate an ac signal without crossover distortion or threshold effect. In this network, an isolated control signal is sufficient for circuit turn-on.
Spool valve accurately controls the cycle of a pneumatically-actuated system over long periods. Regulation of pressure from the external source, positioning of the adjusting plugs, and magnet selection, together afford wide variation in cyclic timing and speed of closure in either direction.
Fluid state vortex valve secondary injection control system shows considerable promise for future application to solid propellant rocket engine thrust vector control. The single axis injection system tested would be capable of providing secondary injection thrust vector control using 2000 deg F gas.
Solid state circuit generating adjustable square wave pulses of sufficient power operates a 28 volt dc solenoid valve at precise time intervals. This circuit is used for precise time control of fluid flow in combustion experiments.
Solenoid valve structure has only one moving part, a ball and spring assembly. This eliminates wear caused by sliding motion contact between stationary and moving parts or between moving parts.