How does this one work?

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Shopgeezer

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In surveying all kinds of steam engines on the net for my own information I came across this one. It has me flumoxed. Looks like a normal slide valve engine but the exhaust seems to come directly out of the cylinder, not the steam chest. Can't figure out how this one works. Anybody know this engine? Also has something weird going on with the bottom of the cylinder. What is the purpose of the long tube? Must be a linkage from the piston rod to the crankshaft.


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deverett

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I don't know the design, but the 'long tube' is known as a trunk guide for the crosshead. These normally have slots cut in the non-bearing surfaces (in the same plane as the crankshaft). This allows access to the crosshead for lubrication.

The piece of flared copper pipe suggests this is a Uniflow type engine. The inlets are at each end and the exhaust is in the middle of the cylinder.
Uniflow steam engine - Wikipedia gives a full explanation of Uniflow type engines.

Dave
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Shopgeezer

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Interesting. The Wikipedia article shows the engine using poppet valves at each end of the cylinder. The engine in the photo looks like a normal steam chest for a sliding valve. I suppose a slide valve engine could be arranged to exhaust pressure from the centre of the cylinder like a uniflow engine. There are so many weird and wonderful designs out in the world.
 

Shopgeezer

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Here is another one. A three cylinder wobbler. Except the cylinders seem to be fixed and the plate bearing the pressure lines does the wobbling. Very weird. Who dreams these things up?

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deverett

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Interesting. The Wikipedia article shows the engine using poppet valves at each end of the cylinder. The engine in the photo looks like a normal steam chest for a sliding valve. I suppose a slide valve engine could be arranged to exhaust pressure from the centre of the cylinder like a uniflow engine. There are so many weird and wonderful designs out in the world.
Elmer did a slide valve Uniflow engine, although he calls it a UnAflow.
For the description, have a look at Elmers Engines Steam Engine Plans
Scroll down and it's no.48 on the hymn sheet.

Your latest curiosity looks interesting!

Dave
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Ken I

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Shopgeezer...

Here's the "D" valve arrangement that allows the exhaust from the centre of the cylinder.
Valveact.jpg

The cross section drawing is without the cylinder heads.
Gerry's beam engine works this way. The pressure enters the steam chest and holds the "D" valve against the face - the exhaust exits tangential to the cylinder. (In your photo the pressure enters via the steam chest cover plate - in Gerry's beam it enters via the side of the steam chest.).
I've just finished designing an Epicyclic using this arrangement (haven't built it yet).
The steam chest does not have to be in the middle of the cylinder - it can be placed anywhere along the length.

Regards, Ken
 
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grahamgollar

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This engine depends on the Rapson Slide design of the followers linked to the eccentric pin. This system is used on, amongst many other things, ship steering engines and Voith Schneider propellers.
 
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