Small footprint knife gate microvalves for large flow control

This paper introduces the first area-optimized micromachined knife gate microvalve. In comparison to recent microvalves the pressure-flow performance is increased using out-of-plane actuators and an out-of-plane orifice. Three different actuator-gate designs and their fabrication are described. The valve features integrated thermal silicon/aluminum bimorph actuators where the aluminum layer forms the resistive heater as well as the bimorph material. The characterization of the actuators and of the pressure-flow performance are presented. The valve allows a flow change of ΔQ=3.4 l/min at 100 kPa on an active chip area of only 2.3×3.7 mm².