The differential pressure flow transmitter has large data errors
Thread Content
The inlet flow meter of the combined compressor is a differential pressure type flow transmitter; during winter, the data errors are large and the values are significantly too low. The anti-surge valve cannot be closed completely, which results in high consumption of medium-pressure steam. After each processing cycle, water is drained from both the positive and negative pressure sides, and after drainage the readings become similar to those of the previous flow meter. The anti-surge valve is fully closed, but as operation proceeds the value decreases gradually, causing the anti-surge valve to open fully automatically. During a winter, this has to be done once or twice a week basically, which poses safety risks and is not conducive to continuous production. I would like to ask the seniors how to handle this? Heating has been added! ! ! !
Heating has been added, which indicates that it hasn’t frozen; the readings returned to normal after draining the waste fluid, suggesting that the flow meter is working properly. In my opinion, it’s possible that the low-pressure pipe isn’t fully unobstructed – it became clear after draining the waste fluid, but it got blocked again shortly after. The pressure guide tube should be removed for a thorough inspection.
May I ask what type of heat tracing was used by the original poster? If it’s steam tracing, try using electric tracing instead.
Measure steam? What’s the temperature? What kind of throttling element, and what is the installation direction? The water flow meter is working fine, so why does it seem like the problem is caused by condensate?
It is necessary to specify what medium’s flow rate is being measured
1. The positive-pressure pipe shows slow clogging； 2. Check whether the bleed line is resting against the positive-pressure pipe, which causes the condensate to evaporate and results in lower readings ；
As far as I understand, since compressors usually have suction tanks, dirt is unlikely to get into the main compressor pipe (that is, the differential pressure gauge tube); the main problem is likely still caused by condensate. I would like to ask about the process: what is the \"dew point\" of the mixed gas at this operating pressure? If it is much higher than the ambient temperature (for example, 50 degrees), it indicates that the material will condense very easily at the ambient temperature. You can also use other pressure/differential pressure transmitters for the same fluid (suction tank level/pressure) to see if any condensate is being discharged. Also, is there such a large deviation in summer? Heating is necessary; it is best to install the transmitter above the pressure tapping point to ensure that the condensate returns to the main pipe. If the transmitter is already in place and it’s inconvenient to shift it, consider filling the pressure guide tube with an isolation fluid and using a tee. @jiaguoyun