Author Topic: Strange reversing mechanism on steam engine  (Read 206 times)

Terrywerm

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Strange reversing mechanism on steam engine
« on: June 27, 2019, 03:42:46 PM »

I just returned from a vacation in Colorado that included a visit to the old mining town of Leadville. While there we visited a local history museum that had some old mining equipment outside. One of the items there was a hoisting engine which was of a different design than anything I had seen before. There is a worm installed on the crankshaft and it engages a large gear on the drum. There is no way to release the gear from the worm, the only way to play out wire rope is to run the engine in the opposite way. If used in a mine with a vertical shaft, this is probably the best arrangement so that any skip used is lowered in a controlled fashion.

Okay, so engines with reversing gear are common, but this one is a bit different. It uses a reverse mechanism built into the valves for each cylinder. I've looked at quite a few steam engines over the years and have never seen anything like this. I am wondering if anyone here has encountered such an engine and is familiar with the mechanism used.

It appears that the engine has piston valves that are inside a rotating sleeve that controls the direction that the engine runs. These sleeves may also control steam flow completely so that one lever is all that is needed to control the hoisting drum. The eccentrics appear to be at 90 to the crank pins.

Please excuse the photos. Due to where this engine was sitting in relation to other equipment, I could not always get the best shots.

So, spit out your ideas, fellas. I find this thing to be quite interesting, and may try modeling this engine at some point in the future.
« Last Edit: June 27, 2019, 03:44:45 PM by Terrywerm »
Terry

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f350ca

Re: Strange reversing mechanism on steam engine
« Reply #1 on: June 27, 2019, 08:03:07 PM »
Thats pretty neat Terry, I've never seen anything like it. Think you might be right that it uses a rotating sleeve to direct the flow.
There were some very innovative designs back then.
Greg

Terrywerm

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Re: Strange reversing mechanism on steam engine
« Reply #2 on: June 27, 2019, 08:47:18 PM »
I sat down and did some work in CAD and have the flow, ports, etc, figured out. Getting the piston valve to seal up inside the sleeve would be easy, just using rings like any other piston valve. Getting the OD of the sleeve to seal properly inside its bore would be another story. Any leakage there would allow live steam to leak right out into the exhaust. But, if designed properly, the valve and sleeve would be about 70% surrounded by live steam, keeping the temperatures rather constant. This way, the sleeve could be machined properly to allow for expansion so that it would make a proper fit within its bore.

There is no way to adjust lap, lead, or cutoff, they would all be constant on this engine. Because of the way it is reversed, lap and lead would be equal for both admission and exhaust.

Anyway, I've put feelers out in a couple other places as well, hoping that somebody can shed some light on this. Keeping my fingers crossed because I think it would be a fun thing to model.
Terry

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jpigg55

Re: Strange reversing mechanism on steam engine
« Reply #3 on: June 28, 2019, 02:16:54 PM »
Welcome back Terry, hope the vacation went well.
I wonder if it uses rotary valves ???
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Terrywerm

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Re: Strange reversing mechanism on steam engine
« Reply #4 on: June 28, 2019, 08:59:37 PM »

No, Jimmy, it does not. You can tell by looking at the valve stem and valve linkage that the valves move back and forth, but are most likely piston valves inside of rotary control valves that control the flow of steam and the direction that it runs. I posted over on Smokstak about my find and a couple of fellows there pointed out what they knew, with one even producing photos of the piston valves and rotary control valves in his boat engine. Needless to say, I now have the information I need to figure out the rest of it.


Oh, and vacation was great. Whitewater rafting on class 3 and 4 rapids was a gas!  Spent time with relatives and finally conquered a trail near Moab called 'Top of the World'.   I'll post some pics of those places a little later. I even got the wife into doing some off-road driving and I think I finally have her hooked!
« Last Edit: June 28, 2019, 09:01:50 PM by Terrywerm »
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