Vortex-shedding flowmeter with unitary shedder/sensor

摘要

A vortex-shedding flowmeter has a flow-pipe (14) with a shedder-sensor unit (15) torsionally supported therein on a pivot axis normal to the flow axis. The torsional support includes a torque tube (17) whose base (17A) is received within a bore in the pipe (14) and is welded thereto and whose tip (17B) is welded to one end of the shedder-sensor unit (15) to provide a fluid-tight structure. In operation, as the incoming fluid stream is divided by and flows past the unit (15), vortices are shed therefrom alternately on either side to develop an alternating torque about the pivot axis, causing the unit (15) to oscillate at a rate proportional to the flow rate whereby the unit (15) acts both as shedder and as sensor. These oscillations are converted into corresponding electrical signals by an external torque transducer (18) operatively coupled to the unit (15) by a rod (21) which extends into the torque tube (17) and is welded to the tip thereof.