The Micro-Isolation Valve - Introduction of Concept and Preliminary Results

A feasibility investigation for a newly proposed microfabricated, normally-closed i so la t ion valve was initiated. The micro-isolation valve is silicon based and relies on the principle of melting a doped plug, opening an otherwise sealed flow passage. This valve may thus serve a similar role as a conventional pyrovalve and is intended for use in micropropulsion systems onboard future microspacecraft, having wet masses of no more than 10-20 kg, as well as in larger scale propulsion systems having only low flow rate requirements, such as ion propulsion or Hall thruster systems. Two key feasibility issues melting of the plug and pressure handling capability were addressed. Thermal finite .element modeling showed that valves with plugs having widths between 10 and 50 (im have power requirements of only 10 30 Watts to open over a duration of 0.5 ms or less. Valve chips featuring 50 micron plugs were burst pressure tested and reached maximum pressure values of 2850 psig (19.4 Mpa).