I currently use a high temperature crab cooker cooker that produces a serious 200,000 btu/hr heat output through a 20 nozzle brass jet cast iron burner. The burner is located 15 inches below the cooking surface to take advantage of where the heat is greatest and all gasses have been combusted,(meaning no black soot on the bottom of the kettle). I originally got this set up because I was tired of waiting for wort to come to a boil using my turkey fryer, and I wanted something that I could eventually use for 10 gallon batches. The burner works great but in doing 5-6 gallon batches I use about 1/2 of the USEABLE propane in the bottle.
I have been looking far and wide for a way to increase the efficency of using this sucker to boil with when I found the DIY link to flash boilers. To me these are gas fired calandrias. I'm looking to put a coil of 3/8"copper pipe coiled under the cooking surface and circulate the wort through this pipe via a march pump. Instead of interupting the burner's flame I plan to just go around it hoping not to get a steam problem.
Has anyone ever done this or could the flash boiler guys chime in on this. I have thought that maybe using 1/2" copper pipe to help with this but I have an old chiller made of 3/8" pipe I need to make use of now that it's obsolete. Since the flash boilers used 3/8" I know this could work. Here is a picture of my burner assembly. The steel is 1/4" so it should provide some protection incase of a failure. I'm not an engineer and thought someone here could be one. Thanks in advace