Patent ID: 7487686

Claim:
A vortex flow meter having adaptive measurement range comprising: a fluid channel having an inlet and an outlet; a vortex shedder having a predetermined dimension, which is positioned in the fluid channel and dividing the fluid channel into an upstream section and a downstream section, a fluid entering the fluid channel through inlet and passing through the vortex shedder to generate periodic vortices in the downstream section; at least one upstream flow field temperature detection device positioned at a selected location in the upstream section of the vortex shedder to detect a fluid temperature (T ∞ ) in the upstream section of the fluid channel for generation of an effective temperature parameter based thereon with respect to a temperature of the vortex shedder; and a frequency measuring device positioned in a selected location in the downstream section of the vortex shedder to measure the vortex shedding frequency; wherein the kinematic viscosity of the fluid at the fluid temperature is looked up from database, and from a relationship between Strouhal number (St) and Reynolds number (Re), the Reynolds number used for the calculation of the flow rate of the fluid is found responsive to the effective temperature parameter.