Practical knowledge

       Accurate measurement and control of mixed media

The YIDU gas mass flowmeter and controller adopt advanced laminar differential pressure measurement principle. In addition to high accuracy, good repeatability, fast response speed, stability and reliability, they also have a magical "special function": freely switch media, and even mix multiple media in any proportion!

        Customer benefits

This undoubtedly greatly expands the application range of a single flow meter, and customers no longer need to distinguish between "hydrogen flow meter" and "nitrogen flow meter". A YIDU laminar differential pressure flow meter is sufficient! The multi gas switching function is already very powerful, and mixing multiple gases in any ratio brings more convenience to customers. However, due to the fact that the YIDU flowmeter is currently one of the few flowmeters that supports mixing gases in any proportion, many customers still encounter misunderstandings when using it.

      Customer Questions

Question 01

Q: My front-end gas source is methane, so I switched the medium of the YIDU flowmeter to methane, but found that the flow deviation was significant and the measurement was inaccurate.

This is a question that many customers have. Even though I switched the flow meter medium to match the actual gas, how could there be such a large error?

Answer: For those who encounter such problems, carefully read the gas source instructions. Is it high-purity methane gas or dilution gas? Although both can be called methane, the gas composition varies greatly. Dilution gas is usually diluted with nitrogen. For example, the gas source composition is:

It can be calculated that the actual methane content is 70ppm (0.007%), which means that more than 99.99% of the gas source is actually nitrogen. In this case, nitrogen should be selected as the flow meter medium instead of methane.

Question 02

Question: Under what circumstances should mixed working fluids be used in proportion?

Answer: The measurement error caused by a small amount of impurity gas is very small. Usually, when the impurity gas content is below 1%, the working fluid can be directly selected as the main gas; The measurement error caused by impurity gas content between 1% and 3% will not exceed 1% Rd. If you want the flowmeter to measure more accurately, you can set it as a mixed working fluid. If the impurity gas content exceeds 3%, in order to ensure high measurement accuracy, the mixed working fluid must be set according to the actual proportion.

For example, if the gas composition you are measuring is 70% nitrogen, 20% air, and 10% hydrogen, you can directly set the proportion in the mixed working fluid, which is very convenient.