| 摘要 |
<p>A system for flow metering apparatus (10) for detecting bubble formation in both clear and opaque fluids in an administration set includes a light source (60) and a light detector (61) positioned on opposite sides of a transparent tubing segment (16) of the administration set such that light transmitted through the tubing (16) to the detector (61) is dependent on the presence or absence of fluid in the tubing (16). With clear fluid present, a first comparator (110) in the system interrupts operation of the metering apparatus (10) when the light detector (61) output falls below a predetermined minimum level. With opaque fluid present, a second comparator (111) interrupts operation of the apparatus (10) when the light detector (61) output rises above a predetermined maximum level. The detection system is automatically conditioned to clear or opaque operating modes without input from the operator, and incorporates protection circuitry for interrupting operation of the metering apparatus (10) in the event of failure of either the light source (60) or the light detection (61). </p> |
