Maximum flow rate of mass flow meter

The maximum value that the flowmeter’s range can reach.

The fluid under test is at specified parameters such as pressure and temperature

Two interpretations 1. Facing the gauge: For a certain diameter and various parameters, what is the maximum flow rate (throughput) that this flow meter can handle? 2. For users: What is the maximum flow rate that this process stage can achieve?

In accordance with the regulations HG/T20507 for the selection and design of chemical process instruments, the maximum flow rate refers to the highest flow rate under normal operating conditions of the process. In addition to the maximum flow rate, there should also be a marked flow rate. 3.1.2 Selection of markings: The markings on the instrument should meet the requirements of the instrument’s modulus; when the marked value is not an integer, it is also possible to choose an integer value for easier reading. 1. For the digital scale range, the maximum flow rate should not exceed 95% of the full scale; the normal flow rate is between 70% and 85% of the full scale; the minimum flow rate should be at least 30% of the full scale. 2. For the linear scale range, the maximum flow rate should not exceed 90% of the full scale; the normal flow rate is between 50% and 70% of the full scale; the minimum flow rate should be at least 10% of the full scale.

This question is quite sophisticated; I’m not trying to flatter the original poster, but it has indeed stumped many people, including some non-technical staff from manufacturers. Generally speaking, the maximum flow rate for mass flow meters – taking Emerson as an example – is around 20 m/s for water flow. No system in China is capable of achieving such a flow rate; I’m not familiar with the situation abroad, but Emerson has set this standard in China. Therefore, this flow rate is only a theoretically calculated flow rate. According to national standards, this method is illegal, as the testing procedures require flow rates at 100%, 50%, 20%, minimum, and 100%; however, Emerson cannot achieve a flow rate of 100%, so it is illegal. Moreover, there are no practical means to ensure it. To verify this issue, you can request the calibration records from the manufacturer; as far as we know, only Qingdao Aowei’s calibration records indicate the same maximum flow rate. So why do manufacturers need this maximum flow rate that is higher than the rated capacity? Since mass flow meters do not meet the requirements in terms of measuring low flow rates, if the maximum flow rate involved is too low, then the range over which such meters can maintain accuracy becomes very limited. For example, many manufacturers offer a range ratio of only 5:1. Therefore, if low flow rates are a concern, it is still necessary to rely on calibration using actual flow rates. Of course, the manufacturers of mass flow meters also need to properly address this issue and cannot resort to such tricks.