Abstract: A piezoelectric pump includes a hollow cylindrical piezoelectric crystal (12) with end bells (22) and (24) on either end defining a pump chamber (14). A resilient diaphram (32) with an offset orifice (34) provides afferent valving action and a resilient diaphram (44) with an offset orifice (46) provides efferent valving action. Connecting leads (52) and (54) allow a voltage source (56) to be periodically connected to the crystal (12) by a switch (62). A resistor (64) is disposed between one pole of the switch (62) and the connecting lead (54) to allow decay of the charge on the crystal (12). By sensing the voltage on the lead (52) during relaxation of the crystal 12, the internal load can be monitored to provide an indication of the pumping operation. Automatic monitoring is provided by a computer (104).

Abstract: A method and apparatus of pumping a fluid by means of a piezoelectric pump is provided. All moving parts, including the valves and impeller, are piezoelectrically motivated. The preferred embodiment includes a piezoelectric ceramic tube having conductive bands adhered to the outer surface. The conductive bands and an inner surface electrode define tube regions which serve as valve and reservoir pump regions.

Abstract: An apparatus for pumping a fluid by means of a piezoelectric pump is provided. All moving parts, including the valves and core, are piezoelectrically motivated. The preferred embodiment includes a piezoelectric ceramic tube having conductive bands adhered to the outer surface. The conductive bands and an inner surface electrode define tube regions which serve as valve and reservoir pump regions. A sensing circuit senses the voltage on the outer electrodes of the innermost of the piezoelectric regions to detect the presence of faulty pumping operation. The sensing circuit utilizes the piezoelectric effect that results from internal loading of the core.