The use of ultrasonic flowmeter and common problems

The use of ultrasonic flow meter and the principle of common problems

The information of the fluid flow rate on the flow of the ultrasonic wave in the fluid. Therefore, the flow rate of the fluid can be detected through the received ultrasonic wave, which is converted into the flow rate. According to the detection method, the method can be divided into different types of ultrasonic flow meter, such as the propagation velocity difference method, the Doppler method, the beam deviation method, the noise method and the correlation method. Ultrasonic flowmeter is a kind of the application of the rapid development of integrated circuit technology in recent ten years.

Non contact type instrument, suitable for measurement and observation is not easy to contact the fluid flow and the large diameter pipe flow. It can be measured with the water level meter linkage to open the flow of water. The use of ultrasonic flow than without the flow state measuring device is mounted in the fluid does not change the fluid, no additional resistance, installation and maintenance of the instrument can not to affect the production pipeline operation is a kind of energy-saving ideal flowmeter.

As everyone knows, the industrial flow measurement exists large diameter and large flow measurement difficult problem, this is because the general flow meter with increasing diameter measurement will bring manufacturing and transport difficulties, cost increase, energy loss increased, not only the installation of these shortcomings, the ultrasonic flow meter can be avoided. Because of all kinds of ultrasonic flowmeter can be installed outside the tube, non contact flow measurement, the instrument cost basically with the measured pipe diameter size, and other types of flowmeters with diameter increasing, cost increases, so the diameter greater than the price of the same ultrasonic flowmeter function function other than the superior type flowmeter. Is considered to be better for large diameter flow measurement instrument, Doppler ultrasonic flowmeter can be measured two-phase flow, it can be used for the measurement of sewers and sewage water and other dirt flow. In the power plant, by measuring the amount of water turbine portable ultrasonic flowmeter machine, steam turbine circulating water flow in large diameter pipe, than in the past the pitot tube flow meter is more convenient. Ultrasonic flow juice can also be used for gas measurement. The scope of the diameter from 2cm to 5m, from a few meters wide open channels and culverts to 500m wide river are applicable.

In addition, the ultrasonic flow measurement accuracy of the meter is almost not affected by the measured fluid temperature, pressure, viscosity, density and other parameters, can be made of non contact and portable measuring instrument, it can solve other types of instruments are difficult to measure the corrosive, non conducting, radioactive and flammable and explosive medium flow measurement the problem. In addition, in view of the non contact measurement features, and then with a reasonable electronic circuit, a meter can be adapted to a variety of diameter measurement and a variety of flow range measurement. The adaptability of ultrasonic flowmeter is not comparable with other instruments. The ultrasonic flow meter has some advantages so it is paid more and more attention to the product series, and common development, standard, has made different channels and high temperature type, explosion-proof type, wet type instrument in order to adapt to the different media, different occasions and different pipeline flow measurement conditions.

The use of ultrasonic flowmeter and common problems

1, ultrasonic flowmeter probe for a period of time, there will be no regular alarm. Especially when the transport medium impurities, this problem will be more common. Solution: regular cleaning of the probe (recommended to clean up once a year).

2, ultrasonic flow meter delivery medium containing water and other liquid impurities, the flow meter is prone to produce liquid, the temperature is low, there will be a pressure tube freeze plugging phenomenon, especially in the northern winter more common. Solution: to the pressure tube blowing or heating with heat

3, ultrasonic flow meter on the pipeline is very strict requirements can not have abnormal sound, otherwise it will affect the measurement error

In the process of propagation, the intensity of the ultrasonic wave can be caused by the obstruction or absorption of impurities in the medium and the medium. Both the ultrasonic flowmeter and the ultrasonic level meter have certain requirements on the received acoustic intensity, so it is required to suppress all kinds of attenuation.

4, instantaneous flow fluctuations?

Signal intensity, the measurement of fluid itself is large.

Solution: adjust the position of the probe, improve signal strength, ensure the signal strength and stability, such as fluid itself fluctuations, the location is not good, to ensure that before the elections, after 10D 5D conditions.

5, outside the clip type ultrasonic flowmeter signal low?

This depends on the technical content of the instrument itself, after a large number of field test examples to prove that such a long time, serious scaling, the problem of large diameter. .

Solution: for large diameter, serious scaling, suggested the use of good quality clamp on ultrasonic flowmeter, probe installation pipe to be polished and clean, with coupling agent or coupling between the probe and the workpiece surface film to exclude air, make the ultrasonic can effectively ensure the incoming pipeline detection has enough surface acoustic intensity transmittance.

6, the measurement of the media in the occasional bubble generated, using the time difference method of ultrasonic flowmeter is affected?

This I-TOP Lille AFTU-2W series clamp on ultrasonic flowmeter has the dual mode, when there is a bubble, can be automatically transferred to the Doppler model to measure, when the bubble disappears, will be automatically transferred to the method of time difference measurement.

7, the instrument in the field of strong interference can not be used?

Field with frequency converter or high voltage cable field electromagnetic interference

Recommendation: far away from the frequency converter or high voltage cable field electromagnetic interference

8, the current market outside the clamp type ultrasonic flowmeter can measure the minimum diameter to the highest temperature? How much?

Answer: now the whole world only I-TOP Montreal AFTU-2W series of minimum diameter can be measured up to 6mm, can measure the temperature to 550 degrees, like measuring molten salt and heat conducting oil of this kind of condition, it is impossible for other brands flowmeter. Electromagnetic flowmeter price

9, how to choose a suitable ultrasonic flow meter?

Answer: pipe material, pipe wall thickness and pipe diameter; fluid type, whether it contains impurities, bubbles and whether the full tube; fluid temperature, flow meter type, is portable or fixed online.

The use of ultrasonic flow meter and common problems needing attention

1, precision function inspection

Accuracy level and function according to the measurement requirements and the use of occasions to choose the accuracy level of the instrument, so that economic value. As for trade settlement, product transfer and energy measurement occasions, should choose high accuracy, such as level 1, level 0.5, level or higher; for process control applications, according to the control requirements of different precision level; some are just check the process flow, do not need precise control and measurement occasion. You can choose a slightly lower level of accuracy, such as level 1.5, level 2.5, or even 4, then you can use low-cost insertion type ultrasonic flowmeter.

2, measurable medium

When measuring the medium flow rate of the medium, the measuring range and the caliber, the flow rate of the ultrasonic flow meter can be selected in the range of 0.5 - 12m/s, and the range is quite wide. Select the instrument specifications (diameter) is not necessarily the same and process pipeline, should be considered in determining whether the scope of measurement of flow velocity range, i.e. when the pipeline flow rate is low, can not meet the requirements or not when the flow meter accuracy measurement of the flow rate of guarantee, need to narrow the instrument port size, thereby increasing the flow velocity in the tube, get satisfactory measurement results.