Can an electromagnetic flowmeter be installed at the pump inlet?

:) The fastest way to solve this issue is to ask the supplier. He will explain it to you clearly.

Some suppliers are really not aware of it.

It is generally not recommended to install electromagnetic flowmeters at the inlet of a pump, especially at the direct inlet of the pump. This is due to the following reasons: 1. Negative pressure issue: There is usually a certain degree of negative pressure at the pump inlet, and if the flow meter is placed there, there is a risk of inaccurate measurements due to the influence of this negative pressure. 2. Bubble interference: If the liquid at the pump inlet contains bubbles, it can severely affect the measurement accuracy of the electromagnetic flowmeter. This is because the electromagnetic flowmeter relies on the electrical conductivity of the liquid to measure flow, and the presence of bubbles leads to unstable conductivity readings. 3. Flow velocity distribution: The flow state at the pump inlet may be a non-fully developed flow, and the flow velocity distribution can be quite chaotic; this as well can interfere with the proper operation of the electromagnetic flowmeter. 4. Mechanical stress: The vibrations and shocks generated by the pump can affect the stability and accuracy of the flow meter, and prolonged exposure to mechanical stress may lead to damage to the instrument. Therefore, it is recommended to install the electromagnetic flowmeter at the pump outlet, usually at a distance of at least 5 pipe diameters from the outlet, in order to ensure a more stable flow regime and avoid the problems mentioned above. At the same time, to ensure measurement accuracy, depending on the specific installation conditions, it may be necessary to leave sufficient straight pipe sections upstream and downstream of the flow meter in order to reduce the impact of turbulence and vortices in the fluid before and after the flow meter on the measurements. .

This post was last edited by zhoudingshengs on 2023-11-28 at 14:46. Animation:

Option C is correct. When installed on vertical pipes, it may result in an underfilled pipe, leading to significant measurement errors. When the two measuring electrodes are directly above and below the pipe, deposits form at the bottom of the pipe when the suspended liquid has a low flow rate, resulting in significant measurement errors.

1. Can an electromagnetic flowmeter be installed at the inlet of a pump? Yes. 2. When installing an electromagnetic flowmeter on a fluid pipeline, which of the following practices is correct? 　 A. When installed on a vertical pipe, the flow direction of the fluid being measured should be from bottom to top. Yes. B. When installed in a vertical pipe, the flow direction of the fluid being measured should be from top to bottom. Good, it’s determined by the downstream pipeline. C. When installed on a horizontal pipeline, the two measuring electrodes should not be directly above and below the pipeline. 　 D. When installed on a horizontal pipe, the two measuring electrodes should be directly above and directly below the pipe. The electrodes can be placed anywhere; a clean level flow meter can be installed in any position.

This post was last edited by zhoudingshengs on 2023-11-29 at 16:36. What was said earlier is good! But what you said in the last paragraph of your text: “usually at least 5 pipe diameters away from the pump outlet,” do you think that is reasonable?

The installation distance of an electromagnetic flowmeter is related to its inner diameter; the typical installation range is from 10 times the inner diameter to 20 times the inner diameter from the pump outlet. This choice of distance helps to prevent interference from liquid noise and turbulence on the electromagnetic flowmeter, while also meeting the requirements for stability and accuracy. During on-site installation, the following points should also be taken into consideration: 1. The electromagnetic flowmeter should be installed in a horizontal section of the pipe, and the pipe diameter should not be too small, nor should the flow velocity be too high. 2. When installing, the distance between the pipeline and the electromagnetic flowmeter should be taken into consideration; this distance must meet the installation requirements while also facilitating maintenance and repair. 3. Determine the installation location of the electromagnetic flowmeter based on the flow direction of the liquid in the pipeline; it should generally be installed on the side of a horizontal pipeline, ensuring that there are sufficient straight sections upstream and downstream of the sensor.

This post was last edited by zhoudingshengs on 2023-11-30 09:57. 1. The flow meter should not be installed at the pump’s inlet; on one hand, there are many bubbles at the pump’s inlet, and on the other hand, the negative pressure can damage the lining of the flow meter； To measure the negative pressure that occurs when a high-temperature liquid has its valve closed, due to the cooling and contraction of the fluid, it is advisable to install a negative pressure relief valve near the sensor. 2. A, C (when installed on a vertical pipe, the flow direction of the fluid being measured should be from bottom to top) ； When installed on a horizontal pipe, the two measuring electrodes should not be directly above and directly below the pipe. Flow meters must not be installed at the lower part of vertical pipes. ）