What is the error margin when using a flow meter designed for measuring hydrogen to measure nitrogen? ?
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There is a area-type rotameter for measuring hydrogen on site, with a range of 100 Nm3/hr. The daily hydrogen consumption is 30 Nm3/hr. Now, consider changing the medium from hydrogen to nitrogen, still using this flow meter. If it still displays 30 Nm3/hr, what is the actual flow rate of nitrogen? ? How is the error calculated? ? ?
My understanding is that the range is the square root of the density ratio. For example, the density ratio of nitrogen to hydrogen is 14, and the square root of that is 3.7. So, with nitrogen, the range becomes 100/3.7 = 27 Nm3/h. In other words, when using nitrogen, it shows 100 Nm3/h, but the actual flow rate of nitrogen is 27 Nm3/h. I’m not sure if this is the correct way to understand it ?
If it is the volume measured directly, it should have little to do with density; as long as the temperature and pressure conditions remain unchanged, it will be the same.
No way, doesn’t the area-type rotameter have anything to do with the medium being measured? ? ?
Check books on chemical process instrumentation and automation and you’ll find out.
This post was last edited by myface on 2018-9-18 09:28. Could I be wrong and have thought it was a turbine?
The second floor is correct; the fifth floor deals with the principle of rotameters.
The measurement indication of a rotameter is related to the density of the medium being measured; it is best to send the rotameter back to the factory for recalibration. Although the conversion relationship can be known, it is too cumbersome to perform such conversions every time data needs to be read on-site.
As can be seen from the calculation formula on the 5th floor, the density of the rotor also needs to be known in order to calculate the corresponding nitrogen flow rate.
The person on the 2nd floor is me, the poster; so my understanding is correct.
It’s just a temporary test; it’s not for long-term use. I just want to know an exact value.