Pump motor rotational velocity measurement method wherein the velocity is determined from measured pressure pulses, which are processed to suppress high frequency variations

摘要

Method for measuring the rotational velocity of a pump motor, whereby the pressure signal (P) is measured at the pump outlet valve and a value proportional to the rotational velocity derived from the time between sequential pressure pulses that exceed a predetermined threshold value. High frequency pressure variations are filter out and the frequency threshold is adjusted to compensate for temperature variations. An Independent claim is made for an arrangement for measuring the rotational velocity of a pump motor with the signal from a pressure sensor filtered by a high pass filter and fed to a comparator, whose threshold vale is adjusted according to ambient temperature. Its output is fed to a timer that measures the period of the signal.