应注意哪些问题 What should be paid attention to when using ultrasonic flowmeter
(1) Select the appropriate flowmeter type according to the different media, flow rate and work site; (2) Install the transducer in a reasonable way according to the different types of ultrasonic flowmeters; (3) Regular maintenance, and check the flowmeter work Status, display connection; (4) Calibrate the flow meter regularly. An electromagnetic flowmeter is used for the sewage discharge measurement in our plant. The flowmeter has been verified before installation. The measurable data is always inconsistent with the values indicated by other flowmeters. What is the reason? It is most likely that the installation position is incorrect. If the flowmeter is installed at the highest position of the system, the air bubbles in the pipeline will seriously affect the measurement accuracy; or the flowmeter is installed on the vertical pipeline where the fluid flows downward, it may cause non-full pipe flow. It is recommended to install the flow meter on a horizontal pipe with a lower system position or a vertical pipe with upward flow. It is best to install an aerator or exhaust valve in the system
全球展望”的新报道，新一代的超声波流量计已经克服了过去落后的技术，并成为监控流量和控制流量的基准技术。 According to a new report on the "Global Outlook for Ultrasonic Flowmeters " published by the American ARC Consulting Group, the new generation of ultrasonic flowmeters has overcome the backward technology of the past and has become the benchmark technology for monitoring and controlling flow. Mr. Wil Chin, research director of ARC Consulting Group, said that ultrasonic technology will gradually become the technology of choice for flow measurement, not just a replacement for traditional flow technology. Mr. Chin estimates that the market for ultrasonic flowmeter products will increase from approximately $ 400 million in 2003 to more than $ 600 million in 2008, which will be comparable to the sales of electromagnetic flowmeters worldwide.
Technological innovation promotes growth Technological innovation promotes rapid growth and the continuous emergence of new suppliers. Recently published "Selection Guide for Ultrasonic and Related Flowmeters", the book lists more than 70 ultrasonic flowmeter suppliers worldwide, of which more than 50 suppliers have their own manufacturing technology. David W. Spitzer, one of the co-authors of the book, noted that most of these vendors are not based on traditional markets in North America and Western Europe. Some important suppliers have begun to establish their markets in Eastern Europe, Japan, and other Asian countries, such as South Korea, Singapore, and China.
There are two basic ultrasonic flowmeter technologies: Doppler frequency shift technology and time difference technology. The working principle of the Doppler ultrasonic flowmeter is to measure the flow velocity of a fluid by measuring the frequency shift of sound waves refracted by discrete sounds, foam, or particles in the fluid. When there is flow, as the flow increases, the frequency offset also increases. 的工作原理是：通过观测超声波在介质中的顺流和逆流传播时间差来间接测量流体的流速。 The working principle of the time-of-flight ultrasonic flowmeter is to indirectly measure the flow velocity of a fluid by observing the time difference between the forward and backward flow of ultrasonic waves in the medium. Where there is a flow rate, the time difference increases as the flow rate increases