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Ultrasonic flowmeter is a non-contact instrument that can measure the flow rate of medium in large pipe diameters and can also be used to measure media that are difficult to contact and observe. Its measurement accuracy is very high and it is almost not interfered by various parameters of the measured medium. It can especially solve the flow measurement problems of highly corrosive, non-conductive, radioactive and flammable and explosive media that other instruments cannot. So what causes the ultrasonic flowmeter to measure inaccurately? The following points are the reasons for inaccurate measurement: 1. The influence of pipeline parameter equipment on the measurement accuracy of ultrasonic flowmeter. Whether the pipeline parameter settings are accurate or not is closely related to the measurement accuracy. If the pipe material and size settings do not match the actual situation, there will be an error between the theoretical pipe flow cross-sectional area and the actual flow cross-sectional area, resulting in inaccurate final results. In addition, the emission distance between ultrasonic flowmeter transducers is the result of a comprehensive calculation based on various parameters such as fluid (sound velocity, dynamic viscosity), pipe (material and size), and the installation method of the transducer. Deviations in the installation distance of the transducers will also cause large measurement errors. Among them, the setting of the inner diameter of the pipeline and the installation distance have a relatively prominent impact on the measurement accuracy. According to relevant data, if the internal diameter error of the pipeline is ±1%, it will cause a flow error of about ±3%. ； If the installation distance error is ±1mm, a flow error within ±1% will occur. It can be seen that only by correctly setting the pipeline parameters can the ultrasonic flowmeter be installed accurately and reduce the impact of pipeline parameters on measurement accuracy. 2. The influence of upstream and downstream straight pipe sections on the measurement accuracy of ultrasonic flowmeter. The calibration coefficient K is a function of the Reynolds number. If the fluid transitions from laminar flow to turbulent flow and the flow velocity distribution is uneven, the calibration coefficient K will change significantly, causing a decrease in measurement accuracy. According to the usage requirements, the ultrasonic flowmeter transducer should be installed at a position where the upstream straight pipe section is 10D and the downstream straight pipe section is 5D. When there are pumps, valves and other equipment upstream, the length of the straight pipe section is required to be "as far away from turbulence, vibration, heat sources, noise sources and radiation sources as possible." If there are pumps, valves and other equipment upstream of the ultrasonic flowmeter transducer installation location, the straight pipe section is required to be above 30D. Therefore, the length of the straight pipe section is the main factor to ensure measurement accuracy. 3. The influence of coupling agent on measurement accuracy. In order to ensure full contact with the pipeline, when installing the transducer, it is necessary to evenly apply a layer of coupling agent on the surface of the pipeline, with a general thickness of (2mm-3mm). Remove the bubbles and particles from the couplant so that the emitting surface of the transducer is tightly attached to the tube wall. Flowmeters for measuring circulating water are mostly installed in water wells, which are humid environments and sometimes flooded. If a general coupling agent is used, it will fail in a short time, affecting the measurement accuracy. Therefore, a high-quality waterproof coupling agent must be selected, and the coupling agent should be used within the validity period, which is generally 18 months. To ensure measurement accuracy, the transducer should be reinstalled and the coupling agent should be replaced every 18 months. 4. The impact of the installation position of the ultrasonic flowmeter transducer on the measurement accuracy. There are two ways to install the transducer: reflective and direct. If the direct-ray installation is used to shorten the sound speed travel, the signal strength can be enhanced. For more information, please visit the company’s official website http://www.yb1518.com/. Please keep this link when reprinting! http://www.yb1518.com/UploadFiles/2015113102935175.jpg