A Piezoelectric Bidirectional Micropump for a Medical Application

In this work, we present recent developments of our novel artificial sphincter system. The highly integrated system consists of several inflatable balloons and a micropump. We will analyse the apparatus concerning the volumes that have to be moved and make a specification for a suitable pump. A bidirectional silicon micropump with active valves is used to meet the worked out requirements of the sphincter prosthesis. The fabrication of the pump is described and the working principle will be explained. A summary of an analytical lumped parameter approach to model the pump’s performance is given. Optimization measures derived from this model are pointed out. The driver electronics is described and energy consumption issues are discussed. Two different pump designs were realized. The measured pump performance concerning the flowrate and the achievable pressure were compared to the theoretical model. A good agreement between model and measured data was found. A maximum flowrate of 1.3 ml/min and a maximum backpressure of 40000 Pa was achieved. The realized pump performance is sufficient for first experimental studies with the artificial sphincter system.