Copper Boiler Design

I am in the process of completing a 5" gauge chassis and it requires a boiler. The boiler is not completely standard and I was concerned that if I built one I may not get appropriate tickets and insurance unless the design was to an approved standard. I was lucky enough to be put in touch with Nigel Thompson who supplied a copy of his presentation "BOILER DESIGN CALCULATIONS FOR COPPER BOILERS" updated November 2017 By Peter Squire And David Vere. This presentation comprises the calculations for barrel thickness, stay pitch, and thread etc etc., with reference to different stay material, alternate barrel rivet ptch, etc. It is most comprehensive. I have used the calculations, which Mr Thompson advised are in the public domain, and designed an excel spreadsheet, which can be used to quickly gauge the effect of changing various parameters. It can also indicate the boiler working pressure on existing boilers, should the barrel thickness be known, along with the other dimensions. I have tested the spreadsheet as far as I can and believe it is proven. Should anyone care to have a copy of the spreadsheet, please message me.

This sounds of great interest to me. Have PM'd you many thanks, JC

Richard

I would be interested in a copy of your excel file. I am looking at a boiler for an LNWR Shunting engjne which i also intend to cary out FEA. It will be interesting to see how the Thompson analysis compares.

Regards

Dave Smith

You have a PM Richard, just FYI

If you are a member of a model engineering club, discuss your boiler design with the boiler inspector, he's going to want to see the boiler at stages as it is built. If you'r not a member, you'll have to find a boiler inspector.

The inspector will be able to advise you on details of construction.

Ian S C

Edited By Ian S C on 18/11/2018 10:22:12

Thank you for your reply, Ian, good advice, but exactly why I designed the spreadsheet, to aid the design and ensure that a completed boiler would obtain approval from our Boiler Inspector. As this is a custom design I was in the process of drawing the boiler in order to present a complete design to our inspector for approval. As a first step I required suitable design calculations, and contacted NAME who, fortunately, put me in touch with Mr Thompson who had collated the calculations from the public domain for his own purposes. Studying the calculations I noted that if they were in the form of a spreadsheet then it would be easy to note the effect of any changing parameters on the design.Even though I am only a hobbyist with Excel, I have previously designed a fully integrated financial spreadsheet for a limited by guarantee Society, which was much more complicated than this boiler design spreadsheet. As you suggest perhaps I should have asked our Boiler Inspector for advice on the construction, however I prefer to research methods and present a finished scheme, which can then be critiqued, that's just how I work.