The total value for the steam pipelines is never equal to the sum of the individual pipelines; can someone explain why?
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I have been to many sites, and whether or not hole plate meters or vortex flowmeters are used, whether it’s Yokogawa or Rosemount meters, the value shown on the main meter is not always equal to the sum of the values shown on the sub-meters. I don’t know why this happens; it’s a common issue, and even the customers can’t figure out the reason. What do you all think?
The money wasn’t spent properly, right? Lol, flow meters have a large degree of error; temperature and pressure compensation are necessary, and when choosing a flow meter, it’s important to consider its accuracy rating as well.
1. Check whether the range of flow fluctuations falls within the accuracy guarantee range of the flow meter. 2. Choose a model that is as close as possible to the lower flow limit. 3. Select an in-line vortex flow meter; differential pressure types such as orifice plates are not recommended, and temperature and pressure compensation is necessary. 4. Follow the proper installation guidelines. 5. Set the parameters correctly. 6. It is normal to encounter differences between the total and partial readings, especially within the accuracy range. It would be unreasonable if there were no difference; a match in the total scores is just a coincidence.
This is quite normal. For example, sometimes there are fewer devices in operation, which results in less gas consumption. The diameter of the main pipe is large, so it might not reach the lower limit of measurement set by the instrument; however, the smaller diameters of the branch pipes may allow for measurement
Add another orifice plate to the main pipe, install a differential transmitter, two sets in total.
For steam pipes, it is also necessary to take into account the losses during transportation, the changes in temperature and pressure within the pipes, as well as the losses caused by the operation of steam traps
The flow rates in the main pipe and the branches are different, which results in varying errors. Additionally, some steam is lost during transmission, so the values will generally not be identical. Instruments can be used to improve accuracy by incorporating temperature and pressure compensation, but this can only reduce the errors; it’s difficult to achieve exact consistency