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Calculating air venting (mains)

Circa1902
Circa1902 Member Posts: 20
in Strictly Steam
Time to add some mains to the system! Can someone help me with the calculation of how many Big Mouths I need?

I think the rule of thumb for Gorton #2 was one #2 for every 20ft of 2" main? Is there a similar rule of thumb I can use for the Big Mouths?

Comments

  • Danny Scully
    Danny Scully Member Posts: 1,437
    2” pipe has .023 cubic feet of air per linear foot. So, 20 feet of 2” has .46 cubic feet of air to be vented. In reality, a Gorton C could handle this.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    Order a big mouth, and when you are ready to install it, cut the boiler off, remove the plug, and refire with your stopwatch in hand. Find the length of time needed for steam to travel from hot header, to the vent tapping.
    With the big mouth installed, time the steam arrival again. Hopefully, the times will be close, but if not, then you need more main venting.—NBC

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