Gas flow meter
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Process equipment requires a continuous supply of compressed air or nitrogen, with a constant gas temperature and pressure. Currently, metal tube float flowmeters are commonly used, but some users have reported inaccurate measurements. Besides using vortex flowmeters, what other types of flowmeters are suitable? There’s no need to recommend mass flow meters! Please make some recommendations.
Rotary flow meters are generally used, such as for dry gas sealing or nitrogen sealing. Choose a well-known brand; its precision should be sufficient. For integrated orifice plates, it is advisable to consult the manufacturer, with the main thing to check being whether the flow range meets the requirements.
Orifice plates and vortex flow meters are currently widely used. For large-diameter pipelines, considering cost factors, insertable orifice-type devices can be considered; for small-diameter pipelines, throttling devices such as orifice plates and Venturi tubes can be chosen. In cases where gas conditions remain relatively stable—especially when there is little variation in humidity—thermal flow meters can also be utilized. Each situation should be analyzed individually
If the temperature and pressure remain constant, using a metal rotor is no problem. The key is to ensure that the supplier performs proper calculations and that the rotor is properly calibrated before it leaves the factory. If the pressure is unstable, it will be impossible to obtain accurate readings, as the actual operating conditions differ from those designed for the instrument, which inevitably leads to inaccuracies. Metal rotors are generally used in applications where high precision isn’t required; they are sufficient for indicating only the general trend of changes. If the actual operating conditions match those designed for the instrument, and if the manufacturer uses proper manufacturing techniques and has carried out calibration, then the readings should be accurate. The problem arises when small manufacturers lack calibration equipment and simply make rough calculations without any calibration, which can result in inaccurate readings.
Currently, vortex flowmeters from E+H and Yokogawa are being considered; they are quite reliable!
Consider a rotameter when requirements are not high
Rotors, orifice plates, vortex flow meters, elbow valves, and the like can all be used to measure gas flow; the user should choose the most suitable one based on the specific process requirements
If the pressure is stable, it’s good to use a rotameter for measurement – isn’t it uncalibrated?
Is the range ratio large? What are the pressure loss requirements? Actually, orifice plates or balance devices should also work