I want to build a monotube steam generator. The plans call for a continuous spiral of about 10 "pancakes" of 5/16 in. copper tubing 13" outside diameter and 4" inside diameter. So - wind your copper tube in an outward turning spiral, a little jog up for separation, then wind an inward turning spiral - ditto, repeato 5 times. Oh! and each coil of each spiral has to be separated by 5/16 in. My copper tube is a/c tubing in coils of 50 ft. so it is annealed and sufficiently strong to withstand the pressures in a monotube generator. I will have to braze two lengths together at some point to achieve my 10 "pancakes", not a problem.
My initial thought was two 3/4 in. plywood plates, 13 in. in diam., 5/16 in. apart, mounted on a 4 in. diam. pipe; wind on copper tube along with a length of 3/8 in. (to allow for spring-back) poly rope. That's nice, now I have an outward spiral of the size I want and spaced between turns. Neatly turn a leg upward and inward and we're ready to do the INWARD turning spiral. Anyone have any brilliant ideas on how to proceed from here. I've been puzzling over this for at least two years and only manage to get my brain turning in spirals.
No reason why I should be the only one puzzling over this - AND - someone must have done this before (Stanley, Doble?). I DO NOT have a shop full of standing machinery, so am looking for a hand method. thanks for any help offered, Mike Gray in Beautiful White British Columbia (it just snowed again last night)