The Foxboro Company

Gerald L Felton

Richard W Miller

Kenneth W Petros

A vortex-shedding flow-sensing instrument comprising a flat-faced vortex-generating plate integral with a downstream sensor-bar having flat sides set back laterally with respect to the rows of vortices shed from the edges of the vortex-generating plate. The side surfaces of the plate are tapered inwardly at a moderate angle, and extend down a short distance to rear surfaces at right angles with respect to the direction of fluid flow. The downstream end of the sensor bar comprises a tail piece the side surfaces of which are tapered inwardly at a moderate angle, and extend downstream a short distance to a rear surface perpendicular to the direction of fluid flow. The sensor bar carries on oil-filled capsule having as side walls a pair of flexible diaphragms effectively in the plane of the sensor-bar side surfaces. These diaphragms transmit alternating vortex pressure pulses interiorly of the capsule to a sensing element in the form of a ceramic disc having piezo-electric properties. The resulting alternating voltage signal developed by this element is coupled through lead wires to an amplifier arranged to produce a flow signal suitable for transmission over relatively long distances.

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North Attleboro, MA, United States of America

Gerald L Felton