Wed Feb 27, 2013 9:24 am by PhillipM
The bore is roughly worked back from keeping the average gas flow speed to a reasonable level, then the rough lengths for placing the harmonics worked back from harmonic pipe theory, then the bore altered to suit that and the bends required (which obviously alter the gas speed) then the length tweaked....it's kinda an iterative process but you get close enough for us after 3-4 iterations. The whole thing was then checked with some welding rod to make sure we could get all the lengths right at those diameters without hitting one pipe with another, then made up following it.#
Final pipe lengths were checked using the high tech method of a rope with knots in fed up the middle of the tubes, then the volumes checked by filling them with water, we ended up within +-1mm of each other in length, and ~2% in volume.