Abbott Laboratories Corporation

Michael E Kelly

Peter A Holst

Frank S Mo

A system and method for mounting a piezoelectric crystal and forming electrical connections to it in an air bubble sensor (10). Piezoelectric crystals (26, 54) are mounted against inner surfaces of two opposed cavities (16, 44) using a conductive epoxy. The conductive epoxy both adhesively secures the crystals in place and provides conductive paths to adjacent conductive pins (28, 30, 46, and 48). To mount one of the piezoelectric crystals, a drop of the conductive epoxy is placed on an inner planar surface of the cavity and the crystal is pushed into the conductive epoxy, forcing the conductive epoxy to flow from under the crystal and into contact with one of the conductive pins. The inner end of another conductive pin is bent over the crystal and a drop of the conductive epoxy is then placed on the outwardly facing surface of the piezoelectric crystal, electrically and mechanically coupling the end of the conductive pin that was bent over, to the outwardly facing surface of the crystal. One of the piezoelectric crystals is electrically excited at its resonant frequency, producing ultrasonic sound waves used to detect gaseous bubbles in a liquid flowing through an intravenous (IV) line disposed in a gap(42) formed between two upright supports (14, 40) in which the piezoelectric crystals are mounted. Bubbles in the line attenuate the ultrasonic signal received by the other piezoelectric crystal, reducing an output electrical signal that it produces in response.

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Mountain View, CA, United States of America

Michael E Kelly