METHOD AND APPARATUS FOR ACOUSTIC MEASUREMENT OF GAS FLOW RATE Russian patent published in 2012 - IPC G01F1/66 

FIELD: physics.

SUBSTANCE: acoustic method of measuring gas flow rate involves measuring gas flow rate based on the change in frequency and phase of acoustic oscillations propagating along the axis of the pipe. Two emitting and two receiving acoustic transducers are placed along the edge of the pipe such that their acoustic axes are perpendicular to the direction of gas flow. The receiving acoustic transducers are spaced apart by a distance shorter than the minimum length of the acoustic wave and lie symmetrically between two emitting transducers, which lie at a distance from the receiving transducers which is sufficient for generating a uniform acoustic wave. Low-frequency acoustic waves propagating towards and opposite the direction of flow are generated alternately. The measured phase shift values are used to calculate the real phase shift, free from errors caused by nonidentity of phase shift values of the receiving acoustic transducers and narrow-band input amplifiers. The volume and mass flow of the gas is determined from the ratio of the Doppler frequency shift to the phase shift of the acoustic wave, calculated through phase shift of signals measured during alternate excitation of radiating acoustic transducers.

EFFECT: high accuracy of measuring gas flow rate.

2 cl, 1 dwg