Efficient Microvalve Driven by a Si-Ni Bimorph

We report on a new type of high-throughput thermally driven microvalve fabricated by using micro-electromechanical system (MEMS) technology. A miniaturized Si–Ni bimorph actuator was incorporated into the valve structure. This allowed the realization of both larger force generation and a longer stroke (the actuation length) combined with shortened response time. Also, a low-voltage actuation (<3 V) and low-energy consumption (<0.2 W) were achieved. The actual size of the fabricated valve is 7.3 ×5.8 ×1.2 mm3. The flow rate of 0 to 500 cm3/min at an air pressure of 47 kPa with a low leakage rate of 0.03 cm3/min and good linearity of air pressure control were achieved. The principles of design and experimental results on flow rate control are presented and discussed.