Reasons for measurement error of orifice flowmeter:1. The differential pressure pipeline is blocked, and the differential pressure pipeline is cleared;2. The differential pressure gauge is faulty, check the differential pressure gauge;3. The indication value of the differential pressure transmitter is obviously deviated, and the indication value of the ruler should be checked;4. The installation direction of the throttling element is wrong, reinstall the throttling element;5. The working condition parameters of the measured medium are inconsistent with those used in the design of the throttling device. Correct according to the relevant formula, and recalculate the differential pressure value if necessary;6. The length of the straight pipe before and after the throttling device is not enough, the length of the straight pipe should be adjusted;7. The inner diameter of the straight pipe section is out of tolerance, the inner diameter of the straight pipe section is actually measured, and the maximum flow rate is recalculated;8. The throttle aperture is out of tolerance, the actual throttle aperture is measured, and the maximum flow rate is recalculated;9. The throttling element is deformed, replace the throttling element;10. There are attachments on the throttling element, clean and replace the throttling element;11. The sharp side of the orifice plate should face the fluid flow direction as the inlet end, and the flared side as the outlet end. If it is installed upside down, the display will be much smaller.Solution: Check the installation direction of the orifice plate, and install the orifice plate correctly.12. The inlet edge of the orifice flowmeter is worn. If the orifice is used for a long time, especially when the measured medium is mixed with solid particles and other impurities, it will cause the geometric shape and size of the orifice to change. If it becomes larger or the edge of the opening becomes blunt, the measured pressure difference will become smaller and the flow rate display will be lower.Solution: Rework the orifice plate.13. Transmitter zero drift: If it is used for a long time, the zero point of the transmitter may drift. If it is negative drift, the displayed pressure difference will decrease and the displayed flow rate will also decrease.Solution: Correct the zero point of the transmitter.14. The length of the upstream and downstream straight pipe sections is not enough. If the upstream and downstream straight pipe sections are not long enough, the gas will not be fully developed, which will cause large errors in the measurement results. If there are multiple elbows in the specified straight pipe section upstream, the measurement will be caused. The result is low.Solution: Transform the steam pipeline so that the length of the upstream and downstream straight pipes meets the specified requirements, and a rectifier is added before the throttling device.15. The three-valve group of the differential pressure transmitter is leaking. If the high-pressure valve or the balance valve in the three-valve group leaks, the measured differential pressure will decrease, and the measurement result will be low.
Solution: If the high-pressure valve in the three-valve group leaks, tighten the valve and replace if necessary. If the balance valve in the three-valve group leaks internally, tighten the valve and replace it if necessary.
Post time: 21-09-21