Compared with other types of ultrasonic flowmeters, the external clamp ultrasonic flowmeter has incomparable advantages. For example, the external clamp type ultra-side flowmeter can install the probe on the outer surface of the pipe, so that the flow is not broken and the flow is measured on the basis of not breaking the pipeline. In addition, its pressure loss is low, almost zero, and it also has a relatively large advantage in terms of price in the large-diameter ultrasonic flowmeter market, and has received a lot of customers’ praise.
However, in fact, in the process of actual use of the external clamp ultrasonic flowmeter, there will be reasons for inaccurate measurement feedback from customers. In fact, this situation is often the user in the installation process ignored these problems, today listed one of them to explain to you.
The external clamped on ultrasonic flowmeter is not correctly verified or calibrated, and we need to know that any flowmeter needs to be verified or calibrated before use. When calibrating or calibrating a reference flow rate is required, the choice of a flowmeter that provides a standard flow rate is very important.
Portable ultrasonic flow meters generally have three sets of probes to choose from, these three sets of probes, respectively, suitable for different pipe diameters, different probes with the host in a sense to become a set of independent flow meters. In flow calibration, calibration devices with different pipe diameters should be used to calibrate all three pipe diameters, and the pipe diameters of the calibration device should be matched with the measuring pipe diameters.
The correct verification method is based on the user’s own use as a reference, as far as possible, the portable ultrasonic flowmeter is calibrated or calibrated on a flow standard device with the same or close to the diameter of the pipe, and ensure that each group of probes of the flowmeter configuration are checked, and the calibrating aperture and probe number records are well recorded to prevent misunderstandings.
Ultrasonic flowmeter has certain requirements for the use conditions and the use environment of the site, and it needs to be used when the conditions are met. If the installation position of the ultrasonic flowmeter can not meet the length requirements of the front and back straight pipe section, there will be measurement errors due to the instability of the field. Many users will also be limited by the instrument measuring well when using, and can not meet the requirements of the installation position, which will have greater measurement errors.
In addition, the external clamp ultrasonic flowmeter of the time difference method is particularly sensitive to the bubbles mixed in the measuring medium, and the bubbles will cause the indication value of the flowmeter to be unstable. If the accumulated gas occurs at the installation position of the probe, the flow meter will not work. Therefore, the installation position of the external clamp-type ultrasonic flowmeter should be avoided as far as possible from the pump outlet, strong magnetic field and electric field, and the high point of the pipeline.
The installation point of the ultrasonic flowmeter probe also needs to avoid the upper and bottom of the pipeline as far as possible, and is installed within the range of 45° Angle with the horizontal diameter, and the installation needs to avoid pipe defects such as welds. At the same time, ultrasonic flow meters are not suitable for installation on the roadside of dense vehicles, and try to avoid using mobile phones or walkie-talkies near the host.
In the process of serving customers for many years, there are often customers who feedback to our company that the accuracy of the external clamp ultrasonic flowmeter is inaccurate. In fact, the inaccurate measurement accuracy of the flow meter also has problems caused by customers in use, such as not accurately measuring the parameters of the pipeline will have a relatively large impact on the measurement accuracy.
Can not accurately measure the parameters of the pipeline resulting in inaccurate metering, portable ultrasonic flowmeter probe is installed outside the pipeline, directly measuring the flow of fluid in the pipeline. This flow rate is affected by the flow rate and the flow area of the pipe (the inner diameter of the pipe), and the data is their product. The pipe area and channel length are calculated by the pipe parameters entered by the user manually. The accuracy of these parameters will directly affect the measurement results.
In another direction, even if the flow meter itself is not a problem, but if the user input pipeline data is not accurate, the measurement results are not accurate, the measurement of pipeline parameters will generally be biased, and the wall thickness of the pipeline will change after a period of use, so the measurement data error can not be avoided.
Therefore, when measuring pipe diameter data, we should also pay attention to the rationality of the method, and the measuring tools and instruments should also be calibrated. When measuring these data, we should pay more attention to the influence of the outer protective layer of the pipe and the corrosion and dirt of the outer surface on the measurement data.
Post time: Nov-05-2023