Influence of insertion type ultrasonic flowmeter main factors
Date：2018-12-29
From：
1 pipe diameter
Calculation of pipe diameter D is accurate, this is not the case, there are few user a serious and precise measurement of the inside diameter of the tube. According to the international standard IS07145 regulations, cannot be measured in diameter case, also allowedaccording to the pipe outer circumference, estimates of wall thickness to determine the inside diameter of the tube, so that determining the diameter of course difficult to accurately. In addition, consider the internal wall of pipeline corrosion, fouling, condensate and other factors. The inner diameter of 1～ 2mm error it is quite common for. It flow influence cannot be ignored.
2 pipe length
Insertion type ultrasonic flowmeter for many users, should not be strange. Insertion type ultrasonic flowmeter is an inserting type instrument, it can only measure the pipe diameter direction several point velocity to calculate the flow, has the nature of sampling. If the requirements of high precision, while the straight section and can not meet the design requirements, then the pipe flow velocity distribution may not be symmetrical to the axis of the concentric circle diameter direction, only measure a few velocity can not fully reflect the whole cross section of the velocity distribution, therefore, must be on the velocity distribution has strict requirements, straight pipe section should be 15 - 25 times the inner diameter of the tube length, so as to fully developed turbulent flow, can reflect the entirecross section with a few flow velocity distribution for uniform velocity tube used for large diameter, on-site general difficult to guaranteesuch a long straight section thus the accuracy is difficult to improve, but as long as the flow is unsteady flow, the velocity distribution is stable, do not change with time, only a few velocity while measuring accuracy is poor, but reproducibility is better.