Problems with the improper installation of the exhaust port in orifice plate flowmeters
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I have a question: the regulations state that for orifice plates or nozzles installed on horizontal and inclined process pipes, if there are drain holes, these holes should be located directly above the process pipe in the case of liquid media. For gas and steam media, it should be directly below the process pipeline. What could be the reason?
When the medium is a liquid, exhaust occurs----------at the top; when the medium is a gas, drainage occurs----------at the bottom
Oh, I see. Thanks
It’s you who’s overthinking it; it’s actually very simple
Standard orifice plate measurement assumes that the flow medium fills the pipe as one of its prerequisites. That is, the medium flows through the entire cross-section of the pipeline. In actual operating conditions, some liquids contain a small amount of gas ； Some gases contain a small amount of liquid. These entrained gases or liquids, when the flow rate is not high, are trapped by the orifice plate and accumulate in front of it, occupying space in the pipeline and preventing the medium to be measured from passing through the orifice plate completely. The purpose of setting up exhaust holes is to discharge these entrained gases or liquids. Therefore, the position of the liquid medium discharge hole should be directly above the process pipeline to facilitate the passage of entrained gas. For gas and steam media, it should be located directly below the process pipeline, allowing the entrained liquid to pass through.
For gases, liquids are impurities; for liquids, gases are impurities