METHOD FOR DETECTING A NO-FLOW SITUATION IN A VORTEX OR SWIRL FLOW METER

摘要

A no-flow condition is detected and indicated by spectral analysis of the output signal of a vortex or swirl flow meter. In a normal, positive flow rate condition large magnitude components are, possibly apart from known interferers like the 50Hz component caused by the electrical power supply, clustered around the frequency of a maximum magnitude component related to the flow rate. In a no-flow condition the components of large magnitude are mostly caused by some motor driving a pump or the like and consist of a basic frequency, e.g., 40Hz, as caused by the motor, and its harmonics, e.g., 80Hz and 120Hz. If a set of large magnitude components comprises a component with a frequency larger than the frequency of a maximum magnitude component multiplied by 1.15 or smaller than the same divided by 1.15 this may already indicate a no-flow condition. Depending on the application, more stringent criteria like the presence of frequency quotients close to small integers like 2, 3 and their inverses or quotients can be employed.