Is it necessary to remove the mass flow meter and send it to a specialized facility for calibration?

From the perspective of rigor and accuracy, it needs to be removed and calibrated by comparing it with a standard gauge. There is now also online calibration using ultrasound, but these are methods that require spending money; their accuracy is quite poor. This is the way in which external firms hired to install flow meters for wastewater treatment typically carry out calibration.

Theoretically, this is required; in practice, it is sufficient for the two parties involved in the settlement to agree on it, and there is no need to conduct tests every year, as that would be costly and time-consuming.

From a professional perspective, those related to trade settlement, security protection, healthcare, and environmental monitoring are subject to mandatory inspection and must be sent for testing. Companies that fall outside this range may decide for themselves. If a company has high standards for quality, it can send the products to a metrology institution for inspection, or it can seek a qualified agency for calibration.

1. According to Announcement No. 48 of 2019 issued by the State Administration for Market Regulation regarding the publication of a list of measuring instruments subject to mandatory regulation, flow meters used for trade settlements are required to undergo mandatory calibration. 2. For other mass flow meters, such as those used for measuring or controlling flow between plants or units, the calibration cycle specified in JJG 1038-2008 for Coriolis mass flow meters can be referred to in order to ensure accuracy in measurement or control. Companies can also decide on their own the calibration cycle, but they should at least regularly verify the zero point.

According to these regulations for calibrating flowmeters, it seems that even in cases of trade settlement, flowmeters with a diameter larger than DN300 do not need to be calibrated

If it’s just about purely seeking trouble or avoiding it； It’s better to do less than to do too much ； To meet external inspections. It’s actually very simple: no disassembly, no testing, no inspection – just attach a label

Where is the certification certificate? How is settlement handled after a trade dispute arises?

This post was last edited by ZhiGE on 2020-7-27 08:52. 1. For use in trade handovers, flow meters with a diameter not exceeding DN300 are subject to mandatory calibration (free of charge)； 2. For flow meters with a diameter exceeding DN300 that are used for trade transactions, although there is no mandatory requirement for calibration, it is still recommended to carry out calibration in order to prevent trade disputes ； The State Administration for Market Regulation has not included flowmeters with a capacity of DN300 or higher in the category of those subject to mandatory inspection, mainly due to cost considerations (mandatory inspection is free). 3. Flowmeters with a diameter exceeding DN300 are difficult to disassemble; external ultrasonic devices can also be used for on-site comparison, mainly for calibration when there is suspicion of errors in the flow measurement provided by the flowmeter.

Thank you. It means that for diameters larger than DN300, it would require extra time and effort on the part of the market supervision agency, and that’s why they set this limit