Summary
The difficulty of optimally orienting an intravascular loop probe of an extracorporeal field electromagnetic flow meter is circumvented by uniting 2 mutually perpendicular loop sensors into a single flow-diameter probe. When one of the loops is unfavorably oriented in the magnetic field, the orientations of the other loop is more favorable. The most unfavorable case is a 45° angle between the magnetic field and the planes of the loops, when the signal drops to 70.7% of the optimal value. By taking the square root of the sum of the squares of the 2 loop transducer signals, one obtains an output for flow and diameter measurements which is independent of the probe orientation. This operation can be accomplished electronically.
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Kolin, A. A system for intravascular, radially orientation-independent electromagnetic flow- and diameter-sensing. Pflugers Arch. 372, 109–111 (1977). https://doi.org/10.1007/BF00582215
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DOI: https://doi.org/10.1007/BF00582215