Ultrasonic air-in-line detector for detecting entrained air in a medication infusion system

摘要

An ultrasonic air-in-line detection system for use in detecting entrained air bubbles in the fluid line of a disposable cassette mounted on a main pump unit is disclosed which can accurately detect entrained air bubbles in any type of fluid, whether clear or opaque. The system uses multiple windowing and air volume number weighting to determine when a threshold count of entrained air in a predetermined number of windows of material pumped occurs, with the alarm being sounded only when this threshold count of air bubbles is present in the multiple window volume. The system of the present invention thus will detect entrained air while avoiding so-called nuisance alarms.