Ultrasonic system for detecting and quantifying of air bubbles/particles in a flowing liquid

摘要

A system using ultrasonic energy for detecting and quantifying air bubbles and/orparticles in a liquid flowing in a tube by a non-invasive and non- destructivetechnique has an ultrasonic sensor having piezoelectric transmitter and receiverelements placed opposing on the outside of the tube wall and energy in the ultrasonicfrequency range is transmitted from the transmitter element to the receiverelement. The received ultrasonic energy is amplified and detected and preferablysplit into a steady state (DC) component and a varying or transient (AC) componentrespectively indicative of the absence and the presence of an air bubble or a particlein the liquid. The two components of the signal are applied to an A/D converterwhose output is supplied to a microprocessor which uses the digital data thatcorresponds to the presence of the varying transient component to indicate thepresence of an air bubble and/or a particle and to measure its characteristics.The presence of the steady-state component indicates that the system is operatingproperly to providing a continuous self check against any system malfunction.