A Compound steam engine idea

[Maryak]

Hi Guys,

I have been playing around with this for a day or so and I think I have a workable/machinable mechanism.

Best Regards
Bob

 

[steamer]

Hey Bob,

I'm trying to understand the exhaust port to Atm or condenser.....

Dave

 

[JorgensenSteam]

Bob-

I am sure it is just me, but I can't follow the diagram at all.

Sounds like an interesting idea though.

 

[Dan Rowe]

Bob,
You have a bunch of us stumped here. ??? If you could show a few more positions of the crank it might make it clear what is moving and what is stationary.

Dan

 

[steamer]

I got it, albeit the internals of the hollow spool valve are drawn in a misleading way.

The steam pipe enters in the red area while the exhaust exits in the yellow area
ignore the apparent mixing of receiver and boiler steam.

Tbe hollow spool has two or more ports drilled axially that meet near the center port

This valve will offer some heat to the receiver steam which should be helpful

Dave

 

[Maryak]

Dave,

Exhaust to atmosphere/back pressure system.

Dan and Pat,

Sorry my diagram is confusing. Now that I have the basics I will try and draw something more readily understood. Meanwhile try looking up Bellis and Morcomb engines as some of these used this system as well as the conventional two valves/eccentrics.

Best Regards
Bob

 

[JorgensenSteam]

Ok, I am beginning to see it.

It is a section of a vertical twin engine.
The piston rods go out the bottom to the crank.

The pistons are shown in section as white rectangles.

My tired little brain is having to work on this one.

 

[ironman]

OK Bob, now we need a nice 3D rendering of this engine. ;D

Ray

 

[steamer]

I have a book with a nice section drawing of an engine similar to this.....I'll dig it up.

Dave

 

[JorgensenSteam]

Ok, here is my slant #2 on the "mystery compound" as I hereby dub this engine.

Picture a twin cylinder compound vertical engine with crank pins 180 degrees apart.
So when one piston moves up, the other moves down.

Now use two standard piston valves between the cylinders, and mount the valve stems to a common yoke that is operated from one eccentric only.

The valve on the right is inside admission.
The valve on the left can also I think be inside admission, and you need passages from the outside of the right valve to the inside of the left valve.

Since the pistons act opposite each other, then valve action can be mirrored (sort of), and operated off of one eccentric. If the engine did not have crank pins at 180 degrees, then you would need two eccentrics to time the valves correctly.

So in order to get the arrangement that Bob has above, stack the two piston valves in a common sleeve, make them into a single valve, and allow exhaust to run inside of it in a hollow space inside the thimble.

That is going to be a long valve, and the only way to change the timing is to make a new valve.

Makes for some unequal passage lengths, but certainly would be a functional engine.

That's my guess. (Wow, I am only 7.5 hrs behind steamer dave. Pretty good in my book, if I am right that is.)

 

[steamer]

I found it Bob,

Vulcan built some compounds that way. It has a balanced valve also because the spool is essentially hollow

Vulcan built one that wasn't balanced also.

Dave

 

[Maryak]

OK Bob, now we need a nice 3D rendering of this engine. ;D

Ray

I hear you, like Xmas it's coming ;D

Dave,

Hope you can find some pictures of the Vulcan.

So in order to get the arrangement that Bob has above, stack the two piston valves in a common sleeve, make them into a single valve, and allow exhaust to run inside of it in a hollow space inside the thimble.

That is going to be a long valve, and the only way to change the timing is to make a new valve.

That's my guess. (Wow, I am only 7.5 hrs behind steamer dave. Pretty good in my book, if I am right that is.)

Close Pat,

You make two valves not one, that way they are independently adjustable using spacers on the central collar of the valve rod, just like the real thing.

Best Regards
Bob

 

[JorgensenSteam]

Ahhhhhh..........so very clever, those designers of old.

 

[steamer]

Hi Bob,

I can do that.....probably by weekend.....crazy at work

Dave

 

[steamer]

Here ya go Bob....let me know if it's enough...

Dave

 

[Maryak]

Thanks Dave, :bow:

A section of the bottom half would be great, as would an end elevation.

Why not just draw the whole thing for me. ;D

Best Regards
Bob

 

[steamer]

Well....I'll see what I can find.... ;D

Dave

 

[Maryak]

I've managed to get most of the way, still a bit more to go

Best Regards
Bob

 

[Dan Rowe]

Bob and Dave,
I was looking for something else when I stumbled on the wiki entry for Vauclain compound.
The article has a link to the US Patent drawings.
http://en.wikipedia.org/wiki/Vauclain_compound

Dan