Issues with the configuration of control valves and flow meters?

It seems there are no mandatory requirements, after all, the installation conditions for flow meters are quite stringent; in many cases, it is necessary to meet the installation requirements of the flow meter first. There are control valves both at the front and at the back.

The control valve is placed at the front, as the process requires metering and regulation for easier control; those with a feedback loop are more conducive to regulation

Generally, the flow meter should be at the front and the control valve at the back. It is mainly considered for the accurate measurement of flowmeters. Since control valves generally have a significant pressure-reducing effect, when flow is regulated through such valves, the flow conditions downstream of the valve become unstable, which can lead to eddies and other phenomena that affect the accuracy of flow meter measurements.

The correct answers are as follows: 1. If the pipeline located after the control valve is at a higher level than the flow meter, it can be placed wherever is convenient. 2. If the pipeline after the control valve is at a lower level than the flow meter, then the control valve must be placed after the flow meter. 3. This is based on the principle that the flow meter cannot be left unfilled. 4. It is recommended to consult the flow meter’s manual

The gear flow meter should be installed as close as possible in front of the control valve, to prevent vaporization caused by pressure drop from affecting measurement accuracy. To facilitate on-site calibration of the flow meter, two calibration gate valves with quick connectors should be installed before and after the cut-off valve upstream of the gear flow meter.

The flow meter should be placed at the front; this is especially true when gas is flowing in the pipeline. Pressure changes have a significant impact on the flow meter. Placing the control valve at a distance from the flow meter can help solve the problem of unstable fluid flow conditions downstream of the valve, which can lead to eddies and other issues that affect the flow meter’s accuracy. The manual should provide detailed information on this

I wanted to ask this question too; after searching, I found that someone had already asked it. I read the replies from everyone, and there were different opinions. I also asked other people about this issue, and the answers they gave me were quite different from those of others. The air ducts are relatively casual in design ； It mainly relates to liquid pipelines; if the liquid is in a saturated or nearly saturated state, the flow meter should be placed before the control valve. This is because if the liquid passes through the control valve, it is prone to pressure reduction and vaporization, which would result in inaccurate readings from the flow meter. But I believe that if it is allowed, it is better to place the flow meter behind the control valve; after all, the flow rate behind the valve represents the actual flow rate. If lag effects are taken into account, the flow rate in front of the control valve during the adjustment process may not be accurate.

It is not clear whether the control valves mentioned by the original poster include ordinary valves. For the repair and calibration of flow meters, valves are generally installed before and after them, with certain distance requirements in place; this is to ensure that the pressure changes caused by the valves as well as fluid vortices do not affect the flow meter.

Personally, I think the control valve should be placed first, as metering is mainly about the flow rate after regulation!

What I’ve always done is place the flow meter in front of the control valve.