PROCESS DETERMINING VOLUMETRIC FLOW RATE OF SUBSTANCES WITH USE OF ULTRASONIC SIGNALS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2001 - IPC

FIELD: measurement technology. SUBSTANCE: emitted and reference signals in the form of bursts of high-frequency oscillations with rectangular envelope are formed in each of 2n (n>1) sequential measurement cycles. Time of propagation of ultrasonic signals emitted with and against flow are converted into two output frequencies. Period of one frequency is multiple of time interval between leading fronts of envelopes of burst emitted with flow and of reference burst. Period of the other frequency is multiple of time interval between leading fronts of envelopes of burst emitted against flow and of reference burst. Coarse adjustment of output frequencies is carried out by way of maintenance of time mismatch between leading front of envelope of reference burst and center of received burst that should be not more than half-period of oscillations filling bursts. Later fine adjustment is conducted. Velocity of flow used to calculate flow rate is determined by difference of output frequencies. Device for implementation of process has two piezoelements, commutator, shock-excitation generator, phase-meter, four flip-flops, two circuits composed of counter, digital-to-analog converter and controllable generator connected in series, control unit incorporating counter of measurement periods, frequency meter, stabilizer of level of input signal, time discriminator, active filter and circuit controlling counters. EFFECT: enhanced noise immunity and measurement precision. 7 cl, 8 dwg