Ultrasonic flowmeter is a kind of velocity flowmeter which USES ultrasonic pulse to measure fluid flow.In recent years, with the development of technology, the use of ultrasonic pulse measurement of fluid flow technology develops very fast, based on different principle, applicable to different situations of various ultrasonic flowmeter has been widely applied, but also for the vast number of users put forward how to further understanding of the ultrasonic flowmeter, how to choose a suitable ultrasonic flowmeter, in use process, what problem should pay attention to and so on

Ultrasonic flowmeter selection and classification:

The selection mainly has the following points: pipe wall thickness, outside diameter, medium, whether the flow in the pipe contains impurities, the temperature of measuring medium, measuring medium for gas, also need to know the pressure of gas, in addition, also should be based on the actual situation of the user and the measurement needs of reasonable selection.

1. Doppler ultrasonic flowmeter

After the transducer passes through the suspended particles or bubbles in the liquid in the pipeline, the frequency will shift. When the pipeline condition, the installation position of the transducer, the transmission frequency and the sound velocity are determined, the fluid velocity can be obtained by measuring the frequency shift, and then the fluid flow can be obtained.It can only be used to measure the fluid containing the right amount of particles or bubbles that can reflect the ultrasonic signal, such as factory discharge, untreated sewage, factory process fluid with stable magazine content, etc.It should be noted that the requirements of the measured medium is relatively strict, that is, it can not be clean water, and the impurity content should be relatively stable, can be normally measured, and the performance of different manufacturers and the requirements of the measured manufacturers are not the same.The choice of this kind of ultrasonic flowmeter is to be measured in mind, but also to choose the ultrasonic flowmeter performance, accuracy and the requirements of the measured medium have a deep understanding.

2. Portable ultrasonic flowmeter

It is mainly used to check the running state of other flow meters installed on the pipeline, carry out fluid balance test in an area, check the current flow condition of the pipeline, etc.If not fixed for these purposes, the portable ultrasonic flowmeter is convenient and economical to use.

3, time difference type ultrasonic flowmeter

The time difference type ultrasonic flowmeter USES the principle that the time difference between the acoustic wave propagation in the fluid and the counter-current propagation is proportional to the fluid velocity to measure the fluid flow.

At present, the production of many, wide range of application is the time difference type ultrasonic flowmeter.It is mainly used to measure clean fluid flow and is widely used in water companies and industrial water use.

4. Pipeline ultrasonic flowmeter

The precision can reach 0.5%, and is not limited by pipe material and lining. It is suitable for the occasions with high demand of flow measurement precision.However, with the increase of pipe diameter, the cost will also increase. Under normal circumstances, it is more economical to choose small and medium-sized pipe segment ultrasonic flowmeter.

5, fixed ultrasonic flowmeter

If there is enough space for installation, the plug-in transducer can be used instead of the externally mounted transducer, which completely eliminates the influence of tube lining, scaling and tube wall on the attenuation of ultrasonic signal, improves the measurement stability, and greatly reduces the maintenance workload.Moreover, because plug - in transducers can also be installed without interruption, so its application is expanding.Some manufacturer launched internal ultrasonic flowmeter for digital circuit, its characteristic is to use digital signal processing circuit, error correction ability enhancement, sampling in a timely manner, improve accuracy (the accuracy of analog circuit is 1.5% and digital circuit can achieve 1.0%), and improved integration, instrument is greatly reduced, there are various signal output modes to choose from, also achieved good effect in practical application.The user can compare the ultrasonic flowmeter with the analog circuit in use.The function choice of ultrasonic flowmeter can be determined according to the actual situation.If two-way fluid is measured, ultrasonic flowmeter with positive and negative metering function must be selected.If the user needs to know the flow rate of the fluid during a certain period of time on a regular basis, the ultrasonic flowmeter with printer can be selected.In short, the functions of the selected ultrasonic flowmeter should not only meet the needs of users, but also need not be more comprehensive, resulting in many functions closed, and increase the cost of purchase.