Regarding the sensitivity of flowmeters under low-flow conditions, which type of meter is more sensitive to low gas flows?
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As stated in the title: the process medium is hydrogen (99%, density 0.18 g/L). Due to differences in conditions such as winter and summer, as well as the load on the equipment, the hydrogen flow rate varies significantly, estimated to range from 10,000 NM3/H to 3,000 NM3/H or even lower. A vortex flow meter is being used, but it does not display any readings at low flow rates; the flow rate reading remains at 0 even when the control valve is adjusted from 0% to 20%, which makes it impossible to measure the flow. Now, we want to replace this flow meter – which type of flow meter would be suitable to address the sensitivity issues at low flow rates? How should I make a choice? The requirement is to increase the opening degree of the control valve; even a 0.5% increase in opening will allow the flow meter to display the flow rate accurately. Common devices used for measuring gases include orifice plates, mass flow meters, venturi meters, electromagnetic flow meters (used for measuring steam), and thermal flow meters (FCI), among others
Ba-type flow meters, those with Ba, Anouba, Weili Ba…
A VeriBa flow meter could be considered...
Can an electromagnetic flowmeter measure steam?
Also, is the cut-off flow rate set too high? The valve is opened to 20 yet there’s still no response
Opening the valve by 20% does not mean that the flow rate is 20% of its maximum value. If it’s small-signal clipping, then it’s way too large.
Quality is the most important factor; if you don’t mind spending more money, you can choose that option. If you want to save costs, it’s better to go with orifice plates
The accuracy of the vortex flow meter is acceptable; it’s possible that the small-signal rejection setting is too high. You can try resetting it.