If it's of any interest there is an article in the Journal of The Trevithick Society 2009:

The Cornish pumping engines restored to steam at Crofton in Wiltshire and at Kew bridge in London. By Peter Stokes.

Or you can pop into the Crofton web site.

http://www.croftonbeamengines.org/intro.html 

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Thrutch, are there any drawings available for the Leawood pump barrel, plunger and valves etc?

That looks like a 2 stage centrifugal blower.

Surely for something requiring the pressure of a beam engine (complete with usual friction), you're going to require something with a bit more meat. Either an exhaust driven turbine, or a turbine driven turbine, or the roots blower route. However, roots blowers don't like too much dP.

It is 2 stage blower, but I am assured this is what powers the engine house. It is a 50inch piston with obviously no rods or underground balance bobs attached, so the only load is part of the beam weight. I plan to see it working so will confirm for sure, as Scooptram says psi maybe not the main parameter for air power but cfm. I guess it also may not be working at its max strokes per min. I know steam boilers worked in the 100's of psi, but not sure what pipe diameter would be relevent in that case.

The n-propyl nitrate sounds interesting but agree its risks (Toxicity and possible explosion / flammabilty risks) would mean it is a no-go.

Anyhow the steam enthusiasts would possibly be up in arms if anything other than coal was used to produce steam if it ever got that far...

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That looks like a 2 stage centrifugal blower.

Surely for something requiring the pressure of a beam engine (complete with usual friction), you're going to require something with a bit more meat. Either an exhaust driven turbine, or a turbine driven turbine, or the roots blower route. However, roots blowers don't like too much dP.

It is 2 stage blower, but I am assured this is what powers the engine house. It is a 50inch piston with obviously no rods or underground balance bobs attached, so the only load is part of the beam weight. I plan to see it working so will confirm for sure, as Scooptram says psi maybe not the main parameter for air power but cfm. I guess it also may not be working at its max strokes per min. I know steam boilers worked in the 100's of psi, but not sure what pipe diameter would be relevent in that case.

The n-propyl nitrate sounds interesting but agree its risks (Toxicity and possible explosion / flammabilty risks) would mean it is a no-go.

Anyhow the steam enthusiasts would possibly be up in arms if anything other than coal was used to produce steam if it ever got that far...

It would have to have rods, otherwise what takes the engine outdoors? It had rods the last time I looked. Working pressure under steam when working would be 40lbs

🔗Parkandillick-Clay-Quarry-Archive-Album-Image-001[linkphoto]Parkandillick-Clay-Quarry-Archive-Album-Image-001[/linkphoto][/link]

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Sorry Spitfire, I wasn't very clear! I meant the rods do not extend underground (ie not the full weight of 100's of fathoms of rods.) :oops:

I guess 40psi is the pressure in the piston chamber?

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Sorry Spitfire, I wasn't very clear! I meant the rods do not extend underground (ie not the full weight of 100's of fathoms of rods.) :oops:

I guess 40psi is the pressure in the piston chamber?

And the boiler, some engines worked at 50lbs but 40 was the norm

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I guess 40psi is the pressure in the piston chamber?

There will be a fair pressure drop in the connecting pipework during the steam admission period and the overall MEP, (mean effective pressure) for the total piston stroke will be surprisingly low.
IIRC Crofton boilers work at 20 PSI and cylinder MEP is about 6 PSI.

Morlock - drawings for the Leawood Pump can be found in The beam Engines of Elsecar, Leawood and Middleton Top by P.J.M. Southworth. ISBN 0-9511856-4-0 The author died recently (and is sadly missed) and so I do not know, just at the moment, what is happening with his website and buisness. I can make further enquiries about this and the availabliity of books at local visitor centres if you wish.
With regard to other matters being discussed here: it might be apocryphal but the attempts to run the Middleton top engine from an electrically powered boiler are said to have resulted in six inch nails being used as fuses and the lights going out in the nearest town - the boiler could not keep pace - c.f.m!
An attempt to start the Leawood engine without water in the pump resulted in a substantial beam in the engine house being smashed - it was before my time at Leawood and I was not there to see it but this story is not apocryphal!
The pressure drop described is very similar to what has been measured at Leawood.

Thanks Thrutch. The enquiry about drawings was purely to speculate on how the set-up could be adjusted to reduce running costs as the pump plunger appears to be ballasted with added weight? Only guessing this from what appears to be a 'ballast hole' in the top of the plunger.

Almost forgot, thanks for the info on the books, will note the ISBN for a future birthday prezzy. 😉

I guess 40psi is the pressure in the piston chamber?

There will be a fair pressure drop in the connecting pipework during the steam admission period and the overall MEP, (mean effective pressure) for the total piston stroke will be surprisingly low.
IIRC Crofton boilers work at 20 PSI and cylinder MEP is about 6 PSI.

The Parkadillack engine worked the same as all Cornish engines i.e. using expansion. So steam admitted at 40 then cut off at one fith stroke giving a final pressure of 8lbs
Now that the engine no longer pumps water air pressure is admitted for the whole of the stroke.

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With regard to other matters being discussed here: it might be apocryphal but the attempts to run the Middleton top engine from an electrically powered boiler are said to have resulted in six inch nails being used as fuses and the lights going out in the nearest town - the boiler could not keep pace - c.f.m!

As I use a small 3 phase electric boiler at work (up to 6 - 9 bar but cfm very low) which is way too small to power anything like a beam engine - yet it has a meaty 440v 3 phase cable going to . It sounds like Middleton would need a dedicated 12kV line (or higher) running to it to get the required power in. I guess the cost of a new powerline would be rather prohibitive ( as well as substation adjustments).

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The pump plunger at Leawood does indeed have a hole through which ballast can be added. We had to adjust the ballast recently after renewing the outlet valve seals. I will be giving this some more thought now - the question has started that process.

When looking at steam pressure on the top of the piston don't forget the vacuum acting on the underside, pulling it down - the Indicator results for the Leawood engine are interesting in this respect.

Went to Parkandillack this afternoon and it was started up using the 2 stage blower (Quite easy, unhook part of the gear, open a valve to let the air in, and lift up a lever). Although we reckoned it would have been very fiddley to start up under steam (as stated in earlier and other posts).
No-one is quite sure what the end of the pump rod is connected to, only that it goes down several fathoms. I asked about a balance bob but no-one recalled one.
Interesting to see the top of the beam with guide rails and the huge spring beam. Apparently this valve gear has a unique design. Anyhow it has got me wanting to find out more about how these machines work ( as I know relatively little!)...anyone advise a good book on the subject?
Pictures have been posted, although there were several good pictures already posted in 2011 and 2008.

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d b barton the cornish beam engine if you can find a copy if you want some storys about beam engines "the cornish beam engine and the men who drove them" jack trounson

Went to Parkandillack this afternoon and it was started up using the 2 stage blower (Quite easy, unhook part of the gear, open a valve to let the air in, and lift up a lever). Although we reckoned it would have been very fiddley to start up under steam (as stated in earlier and other posts).
No-one is quite sure what the end of the pump rod is connected to, only that it goes down several fathoms. I asked about a balance bob but no-one recalled one.
Interesting to see the top of the beam with guide rails and the huge spring beam. Apparently this valve gear has a unique design. Anyhow it has got me wanting to find out more about how these machines work ( as I know relatively little!)...anyone advise a good book on the subject?
Pictures have been posted, although there were several good pictures already posted in 2011 and 2008.

The engine had no balance box, because it is a levered engine

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Spitfire & Scooptram - thanks for info!

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