FLOW RATE MEASURING APPARATUS HAVING VORTEX-GENERATING ELEMENT AND HOT WIRE ELEMENT

摘要

Apparatus for measuring the velocity of the rate of flow of a flowing fluid, comprising a vortex-generating element disposed in a flow tube to create a Karman vortex street in the fluid flow, a hot wire element disposed in the flow tube, transducer means for producing first flow rate signal based on the frequency of shedding of Karman vortices from the vortex-generating element and second flow rate signal based on the cooling effect of the flowing fluid on the hot wire element and signal selection means for selectively putting out the first signal under steady flow conditions and the second signal under pulsating flow conditions. Preferably the hot wire element is made to serve also as the probe element for detection of the vortex generation frequency, and the first signal under steady flow conditions is utilized also to calibrate the second signal.