I would like to install a vent stone on a 3/4" vent line. The line vents upwards of 1500 psig of stored gasous nitrogen in under 1 second. The vent stones are only rated for 300 psig, so I'd like to add an orifice just upstream to limit the exit flow rate to a point where it can handle the pressures from venting the GN2. What are useful formulas for this application? I was thinking perhaps the equation for mass flow rate with choked flow (http://www.grc.nasa.gov/WWW/k-12/airplane/mflchk.html), and also the equation for flow coefficient (http://www.fnwvalve.com/FNWValve/assets/images/PDFs/FNW/tech_AboutCv.pdf). Then I started thinking about the equation for dynamic pressure (http://www.grc.nasa.gov/WWW/k-12/airplane/dynpress.html), but I am struggling with applying these equations to get the information I need. Either I am not using the right approach, or I am not using these correctly.(adsbygoogle = window.adsbygoogle || []).push({});

Thanks for any insight!

-Mike

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# How to size an orifice on a vent line

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