| 摘要 |
FIELD: physics. ^ SUBSTANCE: one radiating and three receiving acoustic transducers are placed along the edge of a pipe such that their acoustic axes are parallel to each other and perpendicular to the direction of flow of the gas. The radiating transducer is placed between the first and second receiving transducers at approximately equal distance from both, where the said distance is three times longer than wavelength of the acoustic wave. The third transducer is placed behind the second transducer in the direction of flow of gas at a distance shorter than maximum wavelength. Exciting oscillations used are low-frequency acoustic oscillations whose frequency is selected such that the wavelength of acoustic waves in the monitored medium is greater than the diametre of the pipe. Volume and mass flow rate of the gas is determined from difference in frequency of acoustic oscillations picked up by the first and second receiving transducers to the phase difference of oscillations picked up by the second and third receiving transducers. The device for realising the said method consists of a primary gas flow rate transducer and an electronic unit. The primary gas flow rate transducer consists of a housing made in form of a pipe section which is mounted in the monitored pipe, one radiating and three receiving acoustic transducers and a primary gas pressure transducer in the main pipeline. The electronic unit consists of self-contained harmonic signal generator, identical narrow-band amplifiers, a microprocessor unit with a digital display device and an interface, a signal mixer, a phase detector, a low pass filter, a pulse former and analogue signal converter. ^ EFFECT: higher measurement accuracy. ^ 2 cl, 3 dwg |
