ULTRASONIC AIR-IN-LINE DETECTOR FOR A MEDICATION INFUSION SYSTEM

摘要

An ultrasonic air-in-line detection system for use in detecting air bubbles in the fluid line of a disposable cassette mounted on a main pump unit is disclosed which can accurately detect air bubbles in any type of fluid, whether clear or opaque. The system uses a windowing technique to determine when a threshold amount of air bubbles in a predetermined volume of material pumped occurs, with the alar? being sounded only when this threshold amount of air bubbles is present in the window volume. The system of the present invention thus avoids socalled nuisance alarms due to the presence of small isolated air bubbles in the fluid due to the fluid pumped not having been degassed.