The portable ultrasonic flowmeter is a kind of ultrasonic flowmeter. Ultrasonic flowmeter is a flowmeter that works in ultrasonic time difference and Doppler mode, because the flow measurement accuracy of the ultrasonic flowmeter is almost independent of the temperature and pressure of the flow being measured. Viscosity, density and other parameters, and can be made into non-contact and portable measuring instruments, so it can solve other difficult to measure flow measurement problems such as strong corrosive, non-conductive, radioactive and flammable and explosive media. The kinds of instruments. Its differentiated performance has won the favor of users.
1. Influence of installation environment, coupler and signal line on measurement
Portable ultrasonic flowmeters mostly use multi-pulse, broadband signals, with a certain ability to resist electromagnetic interference. However, there are high frequencies at the installation site, especially if the frequency conversion interference source is not fully functional. The signal line of the transducer is not easy to be too long, and a coaxial cable of specific impedance should be used, and there should be no joint at the end and in the middle. The ultrasonic coupling agent should be used as far as possible with good sound conductivity and not easy to mix with gas viscous substances, such as water glass, Vaseline, etc.
2, ultrasonic flowmeter is not correctly calibrated
Any flowmeter needs to be verified or calibrated before use, and portable ultrasonic flowmeters are particularly important at this time. Because the portable ultrasonic flow meter is generally equipped with multiple sets of transducers, suitable for different pipe diameter ranges, each set of transducer and the combination of the host is theoretically a set of flow meters. Therefore, if only a small transducer is used to calibrate or calibrate a portable ultrasonic flowmeter on a flow standard device with a small pipe diameter, then if a large transducer is used to measure the flow during use, it is equivalent to using an unverified or calibrated flowmeter with measurement accuracy that cannot be guaranteed. The correct method is based on the user’s own use as a reference, and the portable ultrasonic flowmeter should be checked or calibrated on multiple pipelines on flow standard devices with the same diameter or close to the pipe used. At a minimum, it is necessary to ensure that each set of sensors configured with the flow meter must be calibrated. The meter certification or calibration certificate will give the meter correction factor for several sets of sensors. When using flow timing, be sure to enter the correct meter correction factor for the corresponding transmitter.
3, portable ultrasonic flowmeter shortcomings and limitations
(1) The portable ultrasonic flowmeter of the travel time method can only be used for cleaning liquids and gases.
(2) Ultrasonic flowmeters with external transducers can not be used for pipelines with thick lining or scaling, locally dented or raised pipelines, and pipelines with serious corrosion of pipe walls.
(3) The current domestic production of existing ultrasonic flowmeters can not be used for pipelines with diameters less than DN25mm.
(4) The development and manufacturing of domestic ultrasonic flowmeters is still in its infancy, and the price is high.
Flow measurement is an important parameter in the production process of enterprises, especially in the field of energy conservation and water conservation and other environmental protection has been more and more applied. Portable ultrasonic flowmeter is a new type of flowmeter, its convenience and economy are other flowmeters can not bini. However, the many random errors generated by such instruments require continued study and discussion. For example, changes in the field environment, power frequency, scaling on the inner wall of the pipe, and bubbles in the pipe will cause certain changes in the measurement error value. Therefore, constantly summarize accurate measurement methods from practice, is a long-term task to make good use of portable ultrasonic flowmeters to play its effective role.
Portable ultrasonic flowmeter has the characteristics of fast installation and flexible use, but it must master the accurate method when using. After years of field operation experience, it is found that the use of portable ultrasonic flowmeters is easy to be ignored, analyze the causes of problems and propose solutions.
Post time: Aug-14-2023