http://steamautomobile.com/ForuM/read.php?1,4606I can see you are not using forced circulation, convective instead. I experimented with a convection circulation heat exchanger. It was fantastic demo shoot some steam in the air.
Rollys Derr boiler is the best we've see. For your type of convection flow working properly.
Although monotube steam generators are forced circulation and are made of coiled tubing they have no sight class. The closest to that is something called a "normalizer"
I have taken the time to visit with Tom Kimmel and asked him the questioned since "White" has a normalizer I asked now how does that work?
Tom replied a normalizer is a hole drilled at the very beginning of the superheater. If a maximum quantity of steam entered the end of the monotube would cause steam to be made when the monotube could not produce it. It was a hit with steam car's since if you flooded your monotube with cool water the small amount of water from the drilled hole would generate in the superheater and get the car moving, if the monotube flooded out, although this was uncommon since these steam machines used liquid fuel.
Jeremy Homes aka/JW