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

Abstract: In a flow metering apparatus, a bubble detector for detecting bubble formation in tubing includes a light source and first and second light detectors. The first light detector is positioned on the opposite side of the tubing from the light source such that the light transmitted through the tubing to the detector is dependent on the focusing effect of fluid in the lumen of the tubing. A control circuit responsive to the output of the detector interrupts operation of the metering apparatus when the light transmitted through the tubing falls below a predetermined minimum level. The second light detector is positioned at an angle to the light path between the light source and the first detector so as to receive increased light from the light source in the absence of the focusing effect of fluid in the tubing.

Abstract: A monitor for a plurality of functions associated with a structure such as a livestock confinement structure or the like including detecting fire or intrusion, and monitoring temperature, water supply, ventilation and power supply. The monitor comprises a plurality of sensors mounted at a plurality of locations about the structure adapted for detecting and/or monitoring the above mentioned parameters and providing respective electrical signals corresponding thereto. An electronic circuit is connected with the sensors and includes first indicator circuits connected with the sensors associated with temperature monitoring for producing indication signals in response to variations in the electrical signals therefrom from predetermined ranges of values, and second indicator circuits connected with the remaining sensors for producing indication signals in response to predetermined values of the electrical signals therefrom.