Why are steam prepaid flowmeter results inaccurate
Steam prepaid flow meters are widely used in steam flow metering. With the use of natural gas more and more accurate now, the internal flow value obtained through steam prepaid flow meters has become popular, but as a comparison The delicate instrument is susceptible to interference from external factors and causes the problem of deviation in measurement results, which will affect its use effect.
1. Reason for parameter setting direction:
Due to incorrect parameters, the indication of the steam prepayment meter is incorrect. The parameter error makes the calculation of the secondary meter full-scale frequency wrong. The full-scale frequency is similar, which makes the indication inaccurate for a long period of time. The actual full-scale frequency is calculated to make the full-scale frequency fluctuate. The inconsistency also affected the final determination of the parameters, and finally the parameters were determined by recalibration and comparison with each other, which solved this problem.
2. Selection issues:
Some steam prepaid flowmeters have a larger size in the selection of the caliber or after the design selection due to changes in process conditions. The actual size should be selected as small as possible to improve the measurement accuracy. For example, a vortex The street pipeline is designed to be used by several equipments. Because the process equipment is sometimes not used, the current actual flow is reduced. The actual use caused the original design to be selected too large, which is equivalent to increasing the measurable lower flow limit. Process pipelines The indication cannot be guaranteed when the flow is small, and it can be used when the flow is large, because it is sometimes too difficult to rebuild. Changes in process conditions are only temporary. Can be combined with parameter re-tuning to improve the indication accuracy.
3. The influence of temperature on the measurement The influence of temperature change on the geometric size of the measurement body is composed of two parts. One is caused by the change in the width of the vortex generator; the other is caused by the change in the internal flow of the pipe. To eliminate this effect, the K coefficient is usually modified. At present, some manufacturers' flowmeters have fixed temperature correction and real-time temperature correction in software.
4. The effect of the accumulation of the vortex generator on the front surface of the steam prepaid flowmeter. If there are viscous particles in the measured fluid, it may gradually accumulate on the vortex generator's front surface, causing its geometry and size to change. The flow coefficient also changes accordingly, so pay attention to cleaning during use.
Steam prepaid flowmeters will be affected by the above aspects, so in order to ensure the accuracy of the measurement results, we need to make adequate preparations before use and regularly clean and maintain during use to ensure the measurement of the flowmeter. Will not be disturbed by other factors.