J-TEC developed and perfected the measurement of vortex shedding through ultrasonic sensing in 1968.  An ultrasonic beam, located downstream from a small strut, is transmitted through the vortex pattern.  As the vortices travel through the beam, they modulate its carrier wave.  This signal is immediately processed electronically which provides an exact reading of the flow rate.  Because the number of vortices formed is directly proportional to the rate of flow, it provides a highly accurate and extremely useful method to determine flow in a wide range of applications.

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