The differential pressure of the orifice flow meter is currently too low! How to solve it?
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1. The diameter of the pipes on-site is 250 mm; the inner diameter of the orifice plate currently in use is 75 mm, with a beta ratio of 0.3； 2. The range of the differential pressure transmitter is 0–60 kPa; currently, the instantaneous differential pressure is 2 kPa when it is low, and around 9 kPa when it is high ； 3. Is the differential pressure too low? Can measurement accuracy be ensured? ? 4. Since the beta value is already very small, can I directly use a handheld device to reduce the range of the differential pressure transmitter? Can the measurement error be reduced after the modification? 5. When encountering such a problem, should one consider replacing the orifice plate and changing the pipe diameter, or can the error be reduced simply by adjusting the transmitter’s range?
If the differential pressure is too low, it indicates that the parameters used in the initial calculations were inaccurate. To achieve accurate measurement, it is necessary to recalculate the orifice plate; simply changing the range of the transmitter will not reduce the measurement error.
Thank you! But the beta value is already very small; does that mean the pipe diameter also needs to be reduced?
It depends on the results calculated by the manufacturer.
The diameter of the process pipe has been chosen to be too large; try using 200 mm for the process pipe
The essence of the problem lies in the calculations related to the orifice plate; check whether the parameters you provided are accurate. It is incorrect to modify the range of the differential pressure transmitter – the range ratio for an orifice plate is 0:1, and obviously the flow rate at 2 KPa cannot be determined accurately.
The pipe diameter is too large; a reduction in diameter should be made at this section of the pipe, the orifice diameter should be reduced as well, and then recalculation should be performed. Adjusting the transmitter’s range can cause a significant drop in accuracy. The accuracy of orifice plates isn’t very high to begin with; if their accuracy decreases, it’s better to use a float flow meter instead.
It’s likely that there are issues with both the selection and the calculations; most probably, the problem lies in the parameters specified in the process, so it’s necessary to find the cause at its source.
Changing the pipe diameter is rather troublesome, costly, and time-consuming; the best approach is to provide accurate process parameters and use a different throttling device for calculation. The minimum measurement limits for wedge-shaped, V-cone, or porous balance types are all much lower
1. The pipe diameter is too large, which results in a low flow rate; the pressure difference of 2 KPA is acceptable, and the accuracy should be fine