Device for measuring the flow of fluid through a measuring pipe

Abstract

A device for measuring the flow of a fluid through a measuring pipe, includes a first coil arranged above the measuring pipe, a second coil arranged below the measuring pipe, and a pair of electrodes facing one another, on the sides of said measuring pipe. The coils are excitable and produce both aiding and opposing magnetic fields. A correction circuit corrects the voltage (U.sub.r) between the electrodes. The corrected voltage is approximately proportional to the fluid flow in the presence of aiding magnetic fields when the measuring pipe is partially filled. The correction circuit provides correction to an output signal (S) corresponding to the flow of the fluid when the measuring pipe is partially filled by means of a correction function to a corrected voltage (U.sub.t) which depends on the voltages (U.sub.r, U.sub.g) between the electrodes in the presence of aiding and opposing magnetic fields. The correction function is accomplished by employing a detecting electrode which is arranged at the top of the measuring pipe for detecting complete filling of the measuring pipe. The potential generated by the detecting electrode controls a circuit such that when the measuring pipe is completely filled, the circuit generates voltage (U.sub.r) corresponding to the aiding magnetic fields as an output signal (S), and when the measuring pipe is partly filled, the circuit generate the corrected voltage (U.sub.t) as an output signal (S).