Mass flow measuring method for fluid in pipe, by setting up Karman vortices and determining pressure value representing time-averaged mean dynamic pressure, and flow value

摘要

The method involves producing Karman vortices in the fluid using a blocking body (20), and determining the repetition frequency. The latter is used to produce a flow value XV representing a volume flow or flow rate. The pressures at two spaced-apart points (M1,M2) are the fluid is detected, at least one of the pressures periodically changing under the influence of the vortex produced. A pressure value Xp is produced representing a time averaged mean dynamic pressure acting at least proportionately in the flow direction. The mass flow is determined using the pressure value Xp and the flow value Xv.