If there is a large error between the transit time ultrasonic flowmeter and the electromagnetic flowmeter on site, what issues should be clearly understood?

First, understand the situation of the measurement pipeline, such as the pipeline route, whether there are branch pipes, and whether the installation of the two flowmeters meets the requirements.

Understand the situation of the measured fluid. If there is fluid vaporization and the presence of bubbles, it will affect both flowmeters. Understand the dirtiness of the measured fluid. If the fluid is dirty, it will adhere to the surface of the electromagnetic electrodes during long-term operation, resulting in measurement errors or even measurement failures. For the externally clamped ultrasonic flowmeter, the impact of a dirty fluid is lower than that on the electromagnetic flowmeter because the ultrasonic waves do not come into contact with the medium.

Understand the conductivity of the measured fluid. If the process parameters or operations are changed, it may lead to a change in the fluid conductivity (such as in some pharmaceutical factories), which will affect the electromagnetic flowmeter but not the ultrasonic flowmeter, resulting in different measurement results.

Understand the process parameters of the fluid at the measurement positions of the two flowmeters, with the focus on temperature. Since both measure the volumetric flow rate and generally do not have temperature compensation, although the two meters are connected in series for measurement, if there is a temperature difference due to the distance or process operations, the volume will change due to the density change, making the volumetric flow rates different. Even though the measurement results of both are correct, they will not be equal (Note: The volumetric flow rates are different while the mass flow rates are equal).