Making a simple boiler.

Thanks Jason, I did wonder about cutting the groove, the idea of cutting the end plate does seem to make a lot more sense.

One way or another I'm sure I can get a good seal and built something perfectly safe.

Peter.

hi peter,

although you wont find much online perhaps, ME has contained many many designs for simple steam boiler plants for stationary engines over the years. some of these have already been refered to by previous posters.

i do not think a very thick piece of steel tube, however the ends are attached, will be much use as a boiler as it will take far too much to heat up.

LBSC described a number of very simple quick to build stationary boilers for his Christmas projects and are worth looking at if you want something cheap and simple.

running stationary engines on steam can be a messy business, plus cause problems if not careful with cast iron cylinders and pistons. i would opt for a properly designed copper and silver soldered vertical boiler fired by gas, and of course you will need to fit displacement lubricators to the engines.

cheers,

julian

What Peter could do to minimise the heat up problems is machine the steel to just leave flanges for the screws. If he uses the sums I posted from Harris which are for copper he will have plenty in hand. Leave a rad where the parts neck in just to be ultra safe. There isn't much point in making the flange thickness more than a bit over the diameter of the screws used. It would be a good idea to do the sums on the pressure load and core size of the screws.

If it's a vertical type I suspect he will have problems using an O ring seal at the hot end. Maybe not horizontal with the heat applied a sensible distance from the ends. That would involve applying heat to the thinner sections as well. To use them on a vertical I suspect he would have to machine up a sort of cup along the lines of the usual vertical boiler say 50mm or more deep. That would allow the water to take away heat before it gets to the O ring. 50mm?? I'm guessing. As this is bolted to the tube flanges it doesn't need to be ultra thick.

I asked for ideas on home made burners in another thread. No help at all so far. This might help on that score

**LINK**

Holes could be used instead of slot and the areas reduced for different power levels.

Also this video on youtube - a "cavalier" poster maybe but he does show what burners using propane etc are about. More suitable for horizontal as he shows it.

**LINK**

Obviously there is a need to improve on his lash up and the bit of paper towel air adjustment. Most people know what a bunsen burner adjustment looks like or as some do different size holes etc until it works. Actually the hole size that came with it might be suitable or smaller if less power is needed. Can't say that I am keen on his boilers but suppose they could be pressure tested.

Myford boy on youtube shows a needle valve from the usual blow lamp being used to control a burner for a furnace. The same sort of idea could be used. Actually going back to the cavalier I would wonder about leaving the propane torch alone and fitting the burner tube directly on it. The air mix should then be close to what it should be.

There is some mention of pressure testing by filling completely with water and heating. Various methods of heating are mentioned but I would try a hot air gun first. Bunsen burners and gas stoves sound a bit extreme to me. The pressure will rise and can be read of the boilers pressure gauge. It could also be pumped up with a bicycle pump.

John

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Edited By John W1 on 02/08/2015 11:18:59

Hi Jason,

The Aussie code only specifies the minimum requirements for an amateur engineer to build a safe boiler. Material sizes for the boiler are actually larger than what would be required for a commercial, professionally built boiler to compensate for the lack of skills of some model engineers.

It does not discriminate between operating a boiler to "a man in a shed or only for running in public". No one would know of what you did in the privacy of your own shed unless something went wrong. But would you risk the chance of a boiler exploding and scalding you with boiling water and steam, possibly causing permanent injury to your face and eyes ?

Paul.

It seems that in order to see them the Aussie standards have to be paid for. The introduction on their web site does mention where members of the public etc and locomotives.

**LINK**

Harris mentions the explosion aspect and has the opinion that it's not entirely correct - it's more like the way water pipes burst when frozen. The problem is what comes out - the water is at a temperature that it can only get to under pressure. Release the pressure and it will vaporise into super heated steam where it escapes just like it does from a safety valve.

Interesting link

**LINK**

Must admit I have mixed feeling about this sort of thing. It can get out of hand and kill hobbies completely. Also about comments like that the silver solder didn't break in that pdf - it should add on those tested. Looking at older information on the subject of boiler testing 3x working pressure has been used. I've seen comments about strength safety factors of 6 rather than the 8 Harris uses.

John

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Hi all,

John, the boiler will be a horizontal and I had intended to make a slight flat face along one side as a bottom in order that the area receiving the heat with be slightly thinner. Once I've got a pressure gauge and safety valve and had chance to look at them properly I thought I may also do the same to the top face also.

I'll see how long it takes to heat up etc then if necessary I can always turn down the whole diameter apart from the ends where the plates are bolted. In effect I'll have a tube with inbuilt flanged ends.

Julian who is LBSC ? do you have links please ?

Peter.

Google is your friend ! LBSC

I came across an interesting thought on a vertical boiler so thought it might be worth posting here to keep it all together.

It looks like an interesting mix of water content and heating area to me plus a fair chance of super heating if the space at the top is big enough.

John

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Plenty of vertical boilers like that about John, they usually have a "smokebox" at the top that gathers all the fule gasses into one chimney

I thought that the general proportions of space tor the fire, flue tubes and water are a bit different to what I have seen at the model engineering end. Probably not as efficient but maybe more convenient.

John

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