What is the reason for such a large difference between the steam supply side and the usage side?

Is the distance between the tables far? Has it condensed? Add a bit more superheat!

It could be a measurement error of the gauge; if the gauge lacks temperature and pressure correction, changes in steam pressure and temperature will affect the measurement results.

We have also encountered such situations regarding problems of this kind: 1. When such issues arise, we first need to check whether there is a problem with each flow meter; we need to determine the most accurate measurement range of our flow meters, and if the readings fall outside this range, the error will be significant； (For example, for the steam flow meter in our company with an average flow rate of 15 Ton/H, the deviation from the supplier’s value is around 0.5 Ton. However, when the flow rate is lower, that is, less than 5 Ton/H, the deviation can reach 1-2 Ton.) ； 2. To avoid disputes between the two parties, it is necessary to specify in the contract which flow meter shall be used as the standard for measurement ； How to handle deviations when they occur ； How to perform measurement when one of the flow meters fails ； 3. Traffic related to business must be regularly inspected externally ； (It is necessary to agree on how to handle the situation if the testing party finds defects during external inspection.) ； 4. Additionally, when designing, it is necessary to take into account the need to eliminate certain sources of deviation; for example, by installing the flow meters together with those of the supplier (within our company), some of these deviations can be eliminated.

It’s right on the 6th floor – for settlement purposes, only one table can be used to avoid disputes; the other one can only serve as a reference. The difference in the number of rows between the two tables can vary due to changes in steam temperature and pressure

Steam flow measurement is relatively difficult among all types of fluid flow measurement. Even for the same table on the same pipeline, there can be differences. Currently, flow meters are used to measure steam flow, with the measured medium being single-phase superheated steam or saturated steam. For steam with frequently changing phase flow, there is definitely a problem of inaccurate measurement. The solution to this problem is to maintain the superheat of the steam and minimize its moisture content; for example, by improving the insulation of the steam pipes and reducing pressure losses in the steam, in order to enhance the accuracy of the measurements. However, these methods cannot completely resolve the issue of inaccurate steam flow measurement; the fundamental solution to this problem is to develop a flow meter capable of measuring two-phase flowing media. Regarding the question raised by the original poster, it is somewhat unusual for two flow meters, both of which are vortex flow meters of the same brand and specifications, to show a deviation of over 10%. For a daily usage of around 30 T, with pipes of DN150, my analysis is that your steam consumption is quite low, and the flow rate varies significantly. For the use of vortex flow meters in DN150 pipes, the flow rate range is: 500 KPa = 0.8~12.7 T/h, 1000 KPa = 1.3~19.6 T/h. The data above are those obtained using vortex flowmeters of well-known domestic brands to measure saturated steam. From these data, it can be seen that the range ratio is relatively small. If your steam consumption remains below the minimum flow rate for a considerable period of time, then the difference between the two meters will be significant; a difference of 20% to 30% is possible. Therefore, you need to observe the instantaneous flow changes of your vortex flow meter for a period of time (it is best to connect a paperless recorder so that you can retrieve the recorded curves for analysis), which will help identify where the problem lies.