# Steam valves



## Amber (Jul 29, 2011)

I'm just curious, has anyone tried using a Corliss valve setup on live steam cylinders?
I was also looking into the Joy valve gear, any thoughts on that?


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## Semper Vaporo (Jan 2, 2008)

While I love watching (and hearing!) a Corliss run, I can't believe that it would be at all practical to put on a "moving" steam engine. Way too heavy and delicate to use out on the road (how would you keep the dashpots clear of sand and dirt?)... unless wholly enclosed in a box/cab and gears used to transmit the power to the wheels. And all the Corliss engines I have ever seen had a humongous flywheel and ran relatively slow. Not that it necessarily required a large flywheel, but high speed running like a locomotive would do is possibly outside of the capabilities of a Corliss valve gear.

I am pretty sure Joy valve gear was used on some locomotives but I don't have any examples at hand.


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## Reg Stocking (Sep 29, 2010)

Joy valve gear was used at least a little in Britain. Mr. Joy worked out a design for Patrick Stirling's celebrated eight-foot single express locomotives on the Great Northern Railway. Mr. Stirling rejected it because, no matter how it might improve an engine's performance, it would "look like a laddie runnin' wi' his breeks down>"


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## Amber (Jul 29, 2011)

One of the things about the Joy valve gear, from what I can tell, is it's simplicity. I would guess that it's not a high speed gear, but it would be easier to duplicate than Stephenson valve gear.


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## Phippsburg Eric (Jan 10, 2008)

the corliss valve gear is actually fairly complicated...lots of moving parts; 4 valves per cylinder, snap closing, two cams, dashpots to control rate of valve closure...not a simple system at all. it was designed to improve the efficiency of the engine. as Far as I know it was used only for stationary (mill) engines.

here is one in action:





Stephenson was about as simple as any for use on locomotives (or marine for that matter) 
here it is in action showing how it reverses:





another simple one is Hackworth which uses one eccentric and a sliding shoe...
From Roundhouse Engineering:


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## Amber (Jul 29, 2011)

From what I was reading, I got the impression that the Joy valve gear was a modification of the Hackworth valve gear. They seem to have several similarities. I read something about the Hackworth valve gear not being suitable for high speed use due to vibration of the gear at higher speeds. The Hackworth gear is pretty simple though. I could probably manage to build that or the Joy gear just with my drill press.


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## roadranger (Jan 6, 2008)

The Hackworth valve gear worked best on unsprung drivers, as the raising and lowering of the axle in the pedestals would affect valve timing and consequent running. 

Same problem with Southern valve gear, when the engine leaned into curves the timing changes.

Of course, these were problems on full size locos where movement was in inches. Might not be much of a problem on scale locos as the movement would be negligible.

Roundhouse Models still offers a Hackworth valve gear chassis - on an unsprung frame.


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## Amber (Jul 29, 2011)

Interesting. I wonder if the axle movement would affect the Joy valve movement the way it does the Hackworth.


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## Tom Burns (May 11, 2008)

I can state that there is at least 1 prototype locomotive that utilizes a Hackworth type valve gear. It is located at the Kew Bridge Steam Museum in London. I was not familiar with Hackworth type motion at the time of my visit and watched this little locomotive for some time shuttling people on the little strip of track they have. It is easily visible in this photo on their website.
http://www.kbsm.org/engines/railway
After watching it for some time, I was amazed at the simplicity but recognized that it was not capable of actively adjusting steam cutoff (similar to Accucraft “simplified” and Roundhouse valve gear). For the intended purpose of hauling coal a very short distance to the waterworks boiler from the river, this lack of efficiency was likely an insignificant factor.
I did not however recognize the significant issue identified in prior message that suspension movement will alter valve timing movement (create un-centered movement). I do not recall how the suspension on this 2’ gauge 0-4-0 was configured or wheels equalized. Perhaps someone who has better knowledge of this engine can elaborate.


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## BigRedOne (Dec 13, 2012)

I wonder why no one thought to connect the weigh shaft bearing block to the axle's bearing block? Would appear to solve the problem of suspension travel altering the valve action.


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## Phippsburg Eric (Jan 10, 2008)

http://www.7-8ths.info/index.php?action=dlattach;topic=16685064.0;attach=135483;image

here is a photo showing the hackworth quite well on a British built Kerr Stuart Wren loco.

As your suggestion about connecting the weigh shaft with the axle bearing is logical, perhaps they do indeed do that?


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## Amber (Jul 29, 2011)

That is a very neat little engine! It really shows off the Hackworth gear.


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## Amber (Jul 29, 2011)

Here's an animation for the Joy valve gear. It's different from the Hackworth, but it has a similar slide block in the linkage.
http://www.lner.info/article/tech/valvegear/joy.htm


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## Amber (Jul 29, 2011)

I think a Hackworth gear would work well for a stationary engine type that would run a gear drive or chain drive engine. No axle movement to worry about that way.


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## Phippsburg Eric (Jan 10, 2008)

Well now...if you are going that route, Graham industries makes a very nice screwdriver kit two cylinder vertical engine with hackworth gear...pretty reasonably priced too. I think it is about $250. Similar in size to the ruby engine.

http://grahamind.com/store/page1.html


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## Amber (Jul 29, 2011)

Nice little steam engines there! The twin cylinder vertival engine would work well for a geared engine like a class A Climax.


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## Taperpin (Jan 6, 2008)

Amber, Joy valve gear has a curved slide box and correcting links as well driven off the connecting rod or a small return crank [outside version] it is a very difficult gear to make needing very precise layout and making of the parts. Hackworth is good choice for a first project, simple layout and few parts and the slide box could be made up from K&S square tubing at a pinch.the rest could be made using your drill press and filing etc.
Gordon.


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## Amber (Jul 29, 2011)

Yeah, I hadn't thought about the difficulties of making the curved slide box, that could be a bit more complex than what I could do with just a drill press.


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## HMeinhold (Jan 2, 2008)

Amber,
even simpler is the Marshall valve gear. It does not need any slide blocks, just levers. It was used by Willamette for their reversible steam engines and slightly improved by O&K for their locos in Germany. More information here:
http://www.martynbane.co.uk/modernsteam/klr/badger.htm
and a simulation with editable dimensions for design:
http://www.billp.org/Dockstader/ValveGear.html
Regards


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## Amber (Jul 29, 2011)

There's a lot of interesting types of valve gear on that second page.


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