Abstract: An apparatus for liquid flow detection especially adapted for use with an IV administration set includes an energy beam emitter device and an energy beam detector device. A drip chamber is connected in flow communication with a fluid reservoir of the IV administration set. Fluid flow is directed through a drop forming orifice into the drip chamber and thence into a supply tube for the IV administration set. The energy beam emitter device produces a pair of parallel spaced beams which are directed across the free fall path of the fluid drops and to the energy beam detector device. As the drops enter and exit the energy beams, signals are generated by the detector device as a function of time and are fed to a microprocessor. Using this data and relationships developed with conventional mathematics, the diameter of each drop can be extrapolated. From the drop diameter, the drop volume can then be calculated and used with the time measurements to provide extrapolated outputs of flow-rate and total volume.

Abstract: An apparatus and method for detecting pressure and occlusion in a fluid line is for use with a fluid line being operated upon by a positive displacement, peristaltic pump having several cam follower fingers pressing against the fluid line fluid through the line peristaltically. A sensor follower finger is mounted to the cam shaft of the pump among the other peristaltic fingers in order to cyclicly press against the fluid line and displace the fluid line by a predetermined amount as the cam shaft rotates. The sensor follower finger includes a strain gauge mounted on the sensor finger to generate a signal indicating the degree of force being applied by the sensor finger against the tubing, and a signal processor which receives this force signal and determines the pressure within the fluid line based upon the signal. The signal processor determines the existence of an occlusion based on the signal and provides an alarm if an occlusion is determined.