Effect of pipe diameter change on the measurement of Yokogawa vortex flowmeters
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I would like to ask the forum members: when using a Yokogawa vortex flow meter to measure steam in a pipeline, to what extent does the degree of pipe diameter variation affect the measurement? Or is there some standard that governs this, such as the minimum allowable variation for a DN200 pipe to ensure measurement accuracy? When the straight pipe sections meet the requirements, a pipe was installed on-site that reduces the diameter from DN200 to DN50. A vortex flow meter has been installed on a DN50 pipe. Is such an installation method appropriate? Does the pressure drop caused by the change in diameter have a significant impact on the measurements? Or, if there is enough straight pipe section, it can be ignored. Thank you
Reasonable; the straight pipe section before the fitting should be at least 20*DN50
The straight pipe section just needs to be long enough; of course, the longer, the better. Generally, for a larger diameter change, the minimum required straight pipe sections are 25D upstream and 10D downstream
The vortex flow meter is a velocity-type flow meter that has minimum requirements regarding flow velocity; to obtain accurate measurements, these velocity requirements must be met, and the change in diameter is intended to enable precise measurement.
Given the requirement for straight sections before and after, the degree of diameter change depends on the flow rate range you need to measure.
The process parameters need to be specified for this. It’s impossible to determine whether your information is reasonable. However, according to the design requirements for gauge flowmeters, the necking of the flowmeter should generally be no smaller than two stages; otherwise, the pressure loss will be too high. In this case, it is DN100.
Hey, at Yokogawa, the pipe diameter is determined based on the flow rate; any diameter that meets the required flow rate requirements will do. Then satisfy the straight pipe sections before and after. Flow rate: 2 m/s to 60 m/s; the optimal flow rate is around 40 m/s
Well, what was said upstairs makes sense. With such a large reduction in diameter, the pressure loss is likely to be significant. Sometimes, I have also seen precision traded for pressure loss.
Thank you. There’s everything you can think of. Anyway, thanks
For the selection here, the default flow rate is determined based on the application volume, provided that it can be measured. What I would like to discuss mainly is whether the change in diameter is reasonable. Thank you
Simply put, I just want to know whether such a change in diameter is reasonable; are there any standard requirements, such as the rule that the diameter change should not exceed two specifications? The pipeline carries saturated steam; other aspects will not be discussed for now. Thank you