ANF382 vortex flowmeter measures the flow of steam, gas and low-viscosity liquid based on the theory of Karman and Strohal on the generation of vortices and the relationship between vortices and flow. A triangular prism, i.e., the generator of vortices, is vertically inserted into the meter body. When medium flows through the meter body, regular Karman vortices with opposite directions are generated alternately behind the triangular prism. The separation frequency F of the vortices is proportional to the flow velocity V of the medium. By detecting the number of vortices through the sensor head, the fluid flow velocity can be measured, and then the volume flow of the measured medium can be calculated according to the diameter of the meter body.