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Thread: Flowing nitrogen while brazing

  1. #41
    Join Date
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    Quote Originally Posted by bornjanuary25 View Post
    I suppose that you mean a flow of nitrogen at 5 psi when we braze pipe lines in the system to eliminate oxidation
    My set up uses between 25 and 50 PSI but then has a flow meter on it to reduce it to about 5 CFH. With everything brazed shut you can just feel flow out of an open Schrader fitting.

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  3. #42
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    Dec 2006
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    Quote Originally Posted by bornjanuary25 View Post
    As you know 5 psig form nitrogen cylinder is too low pressure and the flow corresponding this pressure is too low also specifically when you release this flow
    The pipe should not be filled with 5 psi, if you need to run your reg at a high pressure for it to flow properly then you need to use a secondary mesure to reduce the flow so you dont pressurize the pipe. It can be as simple as a ball valve carefully adjusted to limit the flow to what you need for your scenario at play, or you could use a purge regulator to set the flow. Ive done both, it just depends on what you have access to at the time. A flow reg makes an easy and consistent flow setup.

    The plug in the end is only there to help build sufficient velocity out of the pipe plug to stop air from entering the pipe. Too much velocity and you risk pressurizing the pipes and causing blowout (the result of which would show up as a pin hole leak, or in extreme cases it could blow the joint apart before you get it brazed together. You do not want to braze with any pressure in the pipes.
    Quickly, I must hurry, for there go my people and I am their leader!

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