Seek help regarding inaccurate liquid level readings in double-flange transmitters
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Fault symptoms: The level reading of 35LT4031 is inaccurate. When the level of 35LT4022 changes (from 50% to 90%), the level of 35LT4031 only changes by 8% to 10%. Tank F3561 contains propylene; the pressure is 23 KG, and the temperature is around 45 degrees. The measurement range for 35LT-4031 is -4.4 to -2.0 kPa. The double-flange capillary transmitter has been replaced as well; the density is 0.45, and the distance between the two flanges is 50 CM. I suspect that the measurement range is set incorrectly, given that it involves negative-pressure gaseous propylene
The most accurate way to determine this is to first calibrate the transmitter using standard instruments and then assess it.
Set the range to -4.6KPA to -2.4KPA; a lower density results in a lower measurement range, and double-flange level gauges are prone to interference – even slight fluctuations in feed flow can have a significant impact
The double-flange level gauge is good; the LT-4022 level gauge installed on the equipment is also excellent, with a measurement range of -12.6 to -5.2. The flange distance is 150 CM, which is sufficient for feeding and discharging. Did someone upstairs say that fluctuations in the feed amount have an impact? Does that mean such tables cannot be installed?
I think the range is fine; we need to confirm the amount of migration. I usually set the range first (excluding the offset), and after the double-flange transmitter is installed, I carry out zero-point checking and calibration; once calibrated, the offset is automatically determined. It is recommended that you compare it with the liquid level of LT-4022 and use the manual operator to calibrate this level gauge at the current point.
Today, the LT-4031 was removed again; the zero reading at the site was -4.60 KPA, indicating that the zero setting was normal. After it was reinstalled, the LT-4031 showed 20%, while the LT-4022 showed 66%. The magnetic flip display shows 65%, and the radar also shows 66%. Production was asked to try to reduce the liquid level to 62%, but the level in LT-4031 dropped to around 19%; in total, the liquid level has decreased by about 6 CM. The distance between the two flanges of LT-4031 is 50 CM. That means the liquid level has dropped by at least about 12%. Yet the LT-4031 only shows a decrease of around 19%. The unit that was removed earlier also passed the pressure test. Additionally, our LT-4031 measures pressure directly on the equipment itself, (unlike the LT-4022, radar, and magnetic level gauges). It relies on a connecting pipe to take pressure readings.)