Patent ID: 7048519
Filing Date: 2006-05-23
Classification: F04B

Abstract:
1. A piezoelectric pump comprising: a pump housing; a movable diaphragm located within the pump housing and defining a pumping chamber within the pump housing, the pumping chamber having an inlet for admitting fluid into the pumping chamber and an outlet for emitting fluid; a piezoelectric transducer coupled to the moveable diaphragm and operable to move the diaphragm and thereby change the volume of the pumping chamber, wherein the piezoelectric transducer is adapted to sense pressure fluctuations in the pumping chamber; a fluidic valve, operable to restrict fluid flow from the pumping chamber through the inlet; and a flow restrictor, operable to restrict fluid into the pumping chamber through the outlet, wherein the flow restrictor has an acoustic impedance approximately equal to the acoustic impedance of the fluid, so that reflection of sound from the flow restrictor is small relative to transmission of sound through the flow restrictor.