Patent ID: 7661293

Claim:
A system for detecting the presence of an air bubble and/or particle in a liquid flowing in a tube, comprising: an ultrasonic sensor of a transmitter element and a receiver element mounted on the outside of the tube opposing each other; a generator of ultrasonic energy supplied to said transmitter element and transmitted through a liquid flowing in the tube to be received by said receiver element and be converted into an electrical signal at an output of said receiver element; a conditioning circuit which splits said electrical signal into a steady-state component corresponding to there being no air bubble and/or particle in the liquid and a transient state component corresponding to an air bubble and/or particle being present; an analog to digital converter to convert the steady state and transient signal components from the output of said conditioning circuit into digital data; and a microprocessor responsive to the digital data to detect the presence of an air bubble and/or particle in the liquid.