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Compressed air flow rate from pipe to container

  1. Jun 5, 2014 #1
    Hello All,

    I was given a problem today that I could use some guidance on. I have a compressed air pipe flowing into a container. This container has a pressure of 5 psi while the pipe has a pressure of 90 psi. There is a valve that controls when the air is released into the vessel and only allows three seconds worth of compressed air to enter the vessel at a time. My question is what is the volumetric flow rate into the tank during these intervals in Gal/second. The pipe diameter is 1.5" and the compressed air temperature is 70 °F. Any equations or guidance would be helpful, if there's something that I may have left out just post and Ill try to answer as soon as possible. I may be able to collect data to determine other parameters also. Thanks.
  2. jcsd
  3. Jun 5, 2014 #2


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    The flow is a function of the system's geometry and line restrictions. It could be as easy as showing the valve is choked and doing the analysis on the valve. But if the valve is a full port ball valve, that isn't going to be the case and you need to analyze the entire piping run.

    Piping flow analysis isn't something you can throw an equation at and get an answer easily though. It requires some iteration and understanding of how various components may result in the choking of flow at one point or other. If you could detail what your system looks like, it would be fairly easy to do an analysis on it. By that I mean line lengths, pipe ID, elbows and other bends, reducers, expanders, valve flow coefficients, etc... Enough information for someone to build your exact system.

    The easiest way might be to simply buy a rotometer for $50 and slap it on the outlet to measure flow.
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