Ultrasonic flow measuring method and low-power-consumption ultrasonic flow meter

Abstract

The invention discloses an ultrasonic flow measuring method and a low-power-consumption ultrasonic flow meter. The flow meter comprises an MCU module, a power management module, an ultrasonic wave transmitting and receiving module, a temperature and pressure collecting module, a menu function module, a communication function module and a flow output function module, wherein the power management module, the ultrasonic wave transmitting and receiving module, the temperature and pressure collecting module, the menu function module, the communication function module and the flow output function module are connected with the MCU module separately; the ultrasonic wave transmitting and receiving module comprises two pairs of ultrasonic transducers, a first analog switch, a four-way ultrasonic driving circuit, a second analog switch, an automatic gain control circuit and a polarity adjusting circuit. The flow meter has the advantages of high stability and strong robustness, the noise interference resistance is high, the measurement error can be reduced, the measurement stability and precision of the existing ultrasonic flow meter are obviously improved, and in the production process of a gas field, the volume flow of natural gas can be measured reliably, stably and accurately.

Description

technical field [0001] The invention belongs to the technical field of flow detection and relates to ultrasonic flow measurement, in particular to an ultrasonic flow measurement method and a low-power ultrasonic flowmeter. Background technique [0002] At present, there are many domestic ultrasonic flowmeter products with low cost, but the overall performance is not high. Foreign ultrasonic flowmeters are better in terms of accuracy and performance, but they are expensive, which limits their large-scale application in industry. [0003] Ultrasonic flowmeters are mostly measured using the time difference method, and time measurement is mostly based on threshold zero-crossing comparison or cross-correlation algorithm. Threshold zero-crossing comparison has relatively high requirements for the stability and consistency of ultrasonic sensors, and the ultrasonic echo signal must be stable. But at present, the performance of domestic ultrasonic sensors is not particularly good. Th...

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Problems solved by technology

[0002] At present, there are many domestic ultrasonic flowmeter products with low cost, but the overall performance is not high. Foreign ultrasonic flowmeters are better in terms of accuracy and performance, but they are expensive, which limits their large-scale application in industry.

[0003] Ultrasonic flowmeters are mostly measured using the time difference method, and time measurement is mostly based on threshold zero-crossing comparison or cross-correlation algorithm. Threshold zero-crossing comparison has relatively high requirements for the stability and consistency of ultrasonic sensors, and the ultrasonic echo signal must be stable. But at present, the performance of domestic ultrasonic sensors is not particularly good. The performance of foreign sensors is good, but the price is too expensive, which is several times that of domestic sensors.

The cross-correlation algorithm requires a high-speed ADC, and the flow rate is proportional to the forward and reverse flow time difference. In order to obtain high-precision flow measurement, the forward and reverse flow propagation time difference must be measured with high precision. If the time measurement error is 20ns, the sampling rate of the ADC must reach 50MHz. At present, there is no ADC with such a high sampling rate on the market, so the error of flow measurement using this algorithm will be large and the accuracy will be low

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