A Parylene micro check valve

This paper presents a micro check valve that features a bulk-micromachined valve seat (with an orifice) and a new twist-up tethered Parylene-membrane. The twist-up tethers allow large membrane displacement, and thereby reduce membrane-induced flow resistance to a negligible level. Testing results confirm the excellent performance of our valves. For example, the valves have low cracking pressures (less than 0.5 kPa for nitrogen), high reverse pressure (greater than 600 kPa) and low reverse leakage (undetectable with a 0.2 ml/min flow meter resolution). Fluid flow models and analysis of the performance characteristics of the micro valves are presented.