A self-priming and bubble-tolerant piezoelectric silicon micropump for liquids and gases

In this paper a novel silicon micropump for liquids and gases is presented, which is tolerant towards gas-bubbles and which is able to prime itself. The micropump is based on a piezoelectrically driven diaphragm actuator, which is combined with a valve unit consisting of two cantilever valves. The self-priming and bubble-tolerant operation mode was achieved by maximizing the compression ratio, which was realized by minimizing the dead volume of the valve unit as well as of the actuator unit and by maximizing the stroke volume of the pump diaphragm. The optimization of the actuator is based on simulations and experimental investigations of the pump diaphragm displacement. These studies yield the optimal dimensions of the pump diaphragm and the piezoactuator. The piezoelectrically actuated micropump was characterized by investigating the pump rate in dependence of the actuation frequency and the pressure on the inlet and the outlet port of the micropump. As essential results a maximum pumprate of 1 mY/min and a maximum backpressure of about I bar were measured for water. For gases the pumprate ranges up to 3 ml/min.