The steam flow meter data is inaccurate
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Our facility has 4 air separation units, equipped with MAN ST systems. Venturi tube flow meters are installed on the steam pipelines, but currently the readings from these meters do not match those of the customer’s flow meters; there is a certain discrepancy. The flow meters have been calibrated and found to be accurate – so what could be the problem? Everyone is welcome to discuss. What factors can interfere with traffic measurement?
Has the venturi flow meter been compensated for temperature and pressure? Is the flowmeter in charge necessarily accurate? It’s fine to use a differential pressure flow meter to measure steam, but it would be more appropriate to include temperature and pressure compensation. The customer’s main flow meter may not be accurate either... Moreover, are there any devices that generate strong electromagnetic interference nearby, such as pump speed reducers? Should a shielded cable be used, and placed in the instrument tray? In any case, electromagnetic interference does exist in reality; with proper cable shielding, such interference problems can basically be eliminated.
Are your instruments and the customer’s flowmeters of the same type of measurement instrument?
There are many factors that affect the measurement of differential pressure flow meters; interference is one of them. Due to the low pressure difference, leaks or blockages in the pressure transfer tubes have a significant impact on the measurement, so it is necessary to carefully inspect these tubes； Well, the installation also has a significant impact on the measurements.
What type of flow meter is the customer using? Due to different measurement principles, there will certainly be differences in flow rates among various flow meters. If the same flow meter is used, it is necessary to consider the actual operating conditions on site.
We also encounter such situations: the original reasons are as follows – our two flow meters have different designs, and additionally, the two other flow meters have different measurement ranges; especially at low flow rates, the readings from both types of flow meters may not be very accurate； When we sign contracts with clients, we base it on the client’s flow meter (it is agreed that the readings from both flow meters should not differ by more than 5%) ； If it exceeds 5%, the reason must be investigated ； Once, the zero-point drift of the customer’s flow meter was much greater than that of ours; ultimately, our flow meter’s readings were used as the basis for the commercial settlement ；
It’s hard to say for now; in any case, there are significant differences in the settlements with customers, and it’s a lot of money at stake
Generally, it’s not possible to make such an arrangement; since the customer has a large flow meter, of course they will use that one
It is best to specify this in the contract； In principle, it depends on what the customer has agreed to do in case of abnormalities ； In addition, we verify the data with our suppliers at 0:00 every day to check whether there are any discrepancies exceeding the agreed limits ； If it exceeds the specified value, analyze the reasons for the anomaly ； This prevents anomalies during monthly settlements that make it difficult to identify the cause.
First, calculate the difference; it’s probably the data provided by the client’s energy department, but it may not be accurate Furthermore, can you guarantee that your watch is accurate? There are two major issues: firstly, the accuracy is low at low flow rates; secondly, the flow meter fails to compensate due to incorrect parameters set, or the condensation tank is not level, which causes problems with the zero point
Measure the steam flow rate; the flow meter is not located in the same place, and heat loss occurs over long pipelines, so it’s normal to have a difference