Indirect piezoelectric drop counter and method

摘要

The present invention provides an accurate method and apparatus for monitoring the drop flow rate from a fluid source. The drops are indirectly sensed by piezoelectric means mounted on a drip chamber when the drops impinge on a fluid surface in the chamber. The chamber can include a second differential piezoelectric sensing element, which provides a noise reference signal which can be subtracted from the drop sensing signal. The volume of the fluid drops sensed can be determined. The sensing element can be incorporated in open and closed loop disposable chamber modules which can include both monitoring and occlusion valving functions integral therewith.