Bolton triple expansion engine running at last

About 10 years ago I bought a set of castings at the Midlands Model Engineering exhibition just as everyone was packing up, so at a discounted price. In between retirement, moving house and having two books published I managed to do the first build but failed to get it to run with compressed air. I stuck in a box for a year and sulked.

Lockdown prompted me to get it out and strip, then rebuild the whole thing after working out the optimum timing of, and between, the three cylinders.

Today it has run for the first time 😀

I am now designing a frame mounted system that incorporates my vertical boiler with a feed water tank and a CW tank for the condenser together with the condensate and feed water pumps on the engine

Well done - something good out of pesky Corona Virus!

There's a special buzz when an engine runs for the first time, especially if it put up a fight. Any chance of photo?

Dave

Edited By JasonB on 01/02/2021 18:43:13

Nice work Tony!

What a thrill when you open the valve and things start to go round!

Howard

Looking great Tony! well done.

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Nice work.

Very nice work indeed Tony. Did you have the air going through all three cylinders as the steam would?

I've recently finished a tandem compound horizontal that does but it needs an awful lot of air compared to any single built - a lot of it down to the Corliss valves closing too early I'm sure but it does run smoothly.

Working on a marine compound at the moment - not for steam though - just air these days.

Always fancied having a go at the Bolton but all that gunmetal puts me off, shame its not available in cast iron. Yours does look the business though, a really excellent result and something to be truly proud of

Ramon (Tug)

Hi Ramon: because this is a Woolf type engine, that is without inlet chambers before the IP and LP valves the timing is critical so as to avoid stalling back pressure when the HP exhaust starts when running on air. This problem held me up for a couple of attempts over two years. The IP valve has to be opening just as the HP is exhausting.

because air is a compressed gas while steam is an expanding gas when running on air only the HP does any work so at the first run I opened the IP Nd LP cylinder drain cocks but later found it runs with them shut so the air is having to go right through to the condenser.

It has been a long and, due to the cost of the castings, a very careful construction. As I have rebuilt it I have been very impressed by some of my machining!! Not sure I could do it nowadays.

i am now mounting it on a sheet of SS chequered plate and frame and bringing all the water and condensate pipes to a manifold so I can connect it to a matching frame with the boiler and water tank system

Congratulations! A fine project.

Hello Tony,

I remember discussing this issue with my much missed friend and ex work colleague Sid Mountain. He was building this engine but never finished it due to his untimely passing. If I recall correctly he decided in the end that he would bypass one cylinder - I think the HP but it might have been the LP. Sadly Sid succumbed to the big C not that long after he retired and the engine was sold on.

We used to have an exhibitor at our Forncett day that had made a nice working example but that was always run on steam. An ex marine engineer he was in his element when displaying it as you can probably imagine. Much polished it was a bit bright for my eye but a lovely piece of workmanship none the less.

Hope the rest of your build is as successful as the engine appears

Tug

Really nice Tony. I looks like a lot of work went into building that.

Phil H