At present, a large number of mass flow meters have been applied in important measuring places, which often require instruments with high accuracy. In order to meet practical needs, in most cases, users require or have already adopted online verification. Both domestically and internationally, the standards or standard clauses for online calibration of quality flow meters are still very incomplete, resulting in difficulties in application. In summary, there are mainly the following points:

What is the quantitative result of the impact of fluid pulsation on mass flow meters, and how long does it take for a certain amount of pulsation for the mass flow meter to be in a stable and normal working state again. Correspondingly, what corresponding indicators should be met for the flow work standard of calibrating quality flow meters to be qualified?

When conducting online calibration of quality flow meters, should the selection of flow points and flow ranges be based on current standard terms or actual usage flow ranges? The standard should provide clear regulations. Regarding this point, it is particularly prominent in the measurement of trade handover, where both buyers and sellers are unable to persuade each other, creating a vacuum of arbitration. In addition, when implementing the current standard terms, the inability or disallowance of on-site liquid supply equipment and process conditions is a major factor that needs to be considered;

What kind of flow standard device should be used for online calibration of quality flow meters? The current standard text is not very clear. The standard only lists feasible standard device schemes for mass flow meters and does not specifically address online calibration.

We believe that after joining the WTO, the domestic standard setting work should be strengthened. In addition to aligning with the standards, we should also strive to establish our own position and not repeat the mistakes of the DVD standard. In response to the above content, we suggest that the management department commission domestic research institutions, manufacturers, and relevant enterprises in the industry to carry out basic testing and research, and utilize social resources to jointly improve the industry's standard level. In terms of online calibration of quality flow meters, new feasible methods such as "dynamic transfer method" should be adopted and developed.