Vertical boiler design

[nigel jones 5Participant @nigeljones5]

Ive built quite a few in copper for small engines, but now want to build a steel one big enough to easily power a Stuart 5a sized engine without running out of steam! It will also need to provide enough power to allow the 5a to pump water to the boiler. Ive read a few books but cant fathom what size it should be. Any suggestions? Boiler will have 1/2" copper tubes, pre heat coil etc. Coal fed, conventional design. I recon it will need to be quite large! (You cant compare a horizontal loco boiler, they are just too different).

[nigel jones 5Participant @nigeljones5]

[Tony MartyrParticipant @tonymartyr14488]

fizzy

Not an answer to your query I fear but a fellow seeker!

I have exactly the same problem although I would want to fit a ceramic gas burner rather than struggle with coal firing again.

Since moving to deepest southern Shropshire I haven't found any of the model engineering fraternity within a days march of home so I will have to use this forum for advice.

Tony

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Copy of pm sent direct to Fizzy a little while ago :

Hi Fizzy ,

Size depends on numerous things some of which are :

Engine to run for demonstrations only or to develop significant power for some practical purpose ?

Boiler to be worked hard with hot fire and forced draught or worked easy with soft burning fire and natural draught ?

Boiler to work on basis of producing adequate steam continuously with only small reserve or generate steam at a slower rate with large stored reserve ?

Whether boiler is to be used for 5a only or for general purposes where a larger steaming capacity might one day be useful ?

I don’t know what you have in mind but for a general middle of the road design I would suggest something like 7 inches outer barrel diameter and about 14 inches high for the actual boiler – smokebox would be additional length . If size and weight don’t matter I would make it a bit bigger and work the boiler easy . If size and weight a problem I’d go for 6 inches / 12 inches and force the fire .

Nothing is really critical as to proportions except that you need fire tubes relatively long compared to diameter .

nb: A 5a can develop over 1/2 HP at 60 psi 1000 rpm .

Regards ,

MikeW

[Paul Frost 1Participant @paulfrost1]

Hi,

How big a boiler? Try going to **LINK**

Maccsteam.com has the formulas needed for you to work this out. 6” and 7” Copper tube is available, my big steam boiler is made from 1/2” steel pipe cant be moved without a crane weight is a big problem,

Good luck

Paul

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

I was a bit preoccupied when this topic came up and couldn’t spare much time to think about it then .

A few things have occurred to me since :

(1) A vertical boiler of simple design can be made as a mechanical assembly – ie for the most part held together with screws and only some small areas needing welding .

(2) A horizontal Lancashire type boiler similar .

(3) If thinking about a steam raising device in abstract rather than a model of a conventional design boiler then many alternative designs and alternative construction methods become possible .

(4) For conventional designs in larger model sizes there is nothing wrong with rivetted construction .

Regards ,

Michael Williams .

Edited By MICHAEL WILLIAMS on 04/12/2013 11:26:42

[Francois MeunierParticipant @francoismeunier96697]

Hi

for a large engine too, I was tempted to build a boiler similar to this one, riveted and soft soldered only, it looks nice and strong, or should I stop to chicken out and go for a brased job ?

**LINK**

Cheers

Zephyrin

[hushParticipant @hush]

There is an excellent book titled Model Boilers & Boilermaking by K N Harris, it is a worthwhile book to search out.

full of ideas and technical information, it was published by Argus Books Ltd of Watford. in the 1980's

Regards Hush

[Trevor Drabble 1Participant @trevordrabble1]

I have some excellent copies of Model Boilers and Boilermaking by Harris , at least one of which I believe is hardbacked , which I was going to put on fleabay. Will try and establish a fair price over the next couple of days and will post for your consideration.

Trevor

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