2020-11-16
Multi-channel ultrasonic flow meter & single-channel ultrasonic flow meter difference
The transit time ultrasonic flowmeter includes single-channel ultrasonic flowmeter and multi-channel ultrasonic flowmeter. The single-channel ultrasonic flowmeter is to install a pair of transducers on the pipeline or channel to be tested and generate an ultrasonic channel. The measuring device has nonintrusive clamp on type and plug-in type, as well as inline type. Singel-channel ultrasonic flowmeter is simple in structure and convenient to use, but this kind of flowmeter has poor adaptability to changes in flow pattern and measurement accuracy is not easy to control. It is generally used for medium and small diameter pipelines and channels that do not require high measurement accuracy. Multi-channel ultrasonic flow meter is to install multiple pairs of ultrasonic transducers on the tested pipeline or channel to generate multiple ultrasonic channels, and calculate the flow rate by combining the measurement results of each channel.
Compared with single-channel ultrasonic flow meter, multi-channel flowmeters have strong adaptability to changes in flow pattern distribution and high measurement accuracy. They can be used for large-diameter pipes and pipes with complex flow patterns.
The principle of Doppler measurement is to detect the Doppler frequency difference based on the Doppler effect in sound waves. The ultrasonic generator is a fixed sound source. The solid particles moving at the same speed with the fluid move relative to the sound source. The solid particles can reflect the incident ultrasonic waves back to the receiver. The frequency difference between the incident sound wave and the reflected sound wave is the Doppler frequency shift of the sound wave due to the movement of solid particles in the fluid. Since this frequency difference is proportional to the fluid flow rate, the flow rate can be obtained by measuring the frequency difference, and then the fluid flow rate can be obtained.
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