Stayless boilers

[ettingtonliam]

I was reading an article today about Garrett semi portable engines, and was intrigued by the boiler design, which had a horizontal shell with flat circular end plates rivetted on via a circular angle ring. The firebox was circular, corrugated in the larger sizes, with the firetubes fitted to the tubeplate in the normal way. The firebox had an angle ring rivetted to the bottom of it, and the firetubes fitted into a flat plate at the smokebox end. Both end plates of the boiler shell had large circular cut outs to enable the whole firebox and tube assembly to be inserted as one piece and then bolted up with multiple bolts.
This seems to me to have possibilities for a model boiler, as the mass to be heated at any one time is quite small, and the boiler is capable of being fairly readily dismantled for inspection or repair.

Has this been tried in model form, and if so, how well did it work? Do any of the boiler codes preclude this approach to boiler making?
If its a new idea, then presumably I'd need to get the design OK'd by some authority (which one) before starting work. The plan would be to make it in copper. No I wouldn't think of using brass bolts, but how about stainless?

Richard

[alanstepney]

I think K.N.Harrrs either did a design or wrote about, that type of boiler.
Someone else here may recall which.

Dont use stainless in any form in a boiler. It does suffer from problems, and hence most boiler inspectors wont accept it (even if it may be OK in that specific use.)

[daveburrage]

I think fire engine boilers were often bolted together. They had small water volumes (presumably to minumise time to full pressure) so I suspect they would be split periodically to descale the inside.

regards

Dave Burrage

[isc]

If you are using bolts, I think bronze is the way to go, the experts will say yea or ney to that. isc

[ettingtonliam]

Any advice on what grade of bronze. Presumably not phosphor bronze, given the abhorence of phosphorous in boiler materials.

Richard

[Nigel Bennett]

There are a lot of boilers about with phosphor-bronze bushes. The material typically contains less than 1% of phosphorus, and even if it's adjacent to the fire, shouldn't cause problems with degradation.