Microvalve with ultra-low leakage

This paper reports a reduction of microvalve leakage based on precise measurements of leak and flow rates. The tight contact between a valve cap and seat, which is obtained by nanometer-scale flat surfaces and by self-alignment of the cap and seat-bore, makes the leakage from a microvalve ultra-low. The leak and flow rates are determined by precisely measuring pressure changes when introducing helium gas into a flow line. We have, consequently, attained a leak rate as low as 5.8×10^-10 Pa.m³/s and a flow rate ranging from 4.0×10^-6 to 3.2×10^-4 Pa.m³ /s