A piezoelectrically actuated fluid pump including a pump housing, a pump chamber, inlet and outlet ports for communicating the pump chamber with the exterior of the pump housing, valves for opening and closing the ports, a pre-stressed piezoelectric diaphragm member which is self-actuated, a piston member,...http://www.google.es/patents/US6071088?utm_source=gb-gplus-sharePatente US6071088 - Piezoelectrically actuated piston pump
