A piezoelectric micropump based on micromachining of silicon

The design and realization of two pumps based on micromachining of silicon are described. The pumps, which are of the reciprocating displacement type, comprise one or two pump chambers, a thin glass pump membrane actuated by a piezoelectric disc and passive silicon check valves to direct the flow. Chambers, channels and valves are realized in a silicon wafer by wet chemical etching. The results of mechanical calculations and simulations show good agreement with the actual behaviour of the pumps. It is possible to design pumps having a specific yield and pressure dependence, and which are fail-safe (the flow is blocked while the pump is switched off)