Odd reversing system

[TerryWerm]

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.

[Admiral_dk]

Okey that is neat 

One small simple engine, and a very simple and intuitive single lever control handle. Small steam consumption for a good amount of work. Would not have been quick going up or down me thinks, but probably just as well with a simple "chair" in the lift.

[cnr6400]

Thanks for those pics Terry, that valve system is a new one for me!   

[Dan Rowe]

Terry, I found a few examples of this type of valve here:
http://www.douglas-self.com/MUSEUM/POWER/rotaryvalvesteam/rotaryvalvesteam.htm

Very simple design think about material expansion in any model design.

Dan

[b.lindsey]

Leadville is a great place as are many of the old Colorado mining towns. Too bad that engine has been left out in the elements, but still a neat design.

Bill

[crueby]

The smaller Marion engines also did the reversing in the ports, they swapped the steam and exhaust flows, but in a very different way than this one. Were there any maker names on the engine? If so could probably find a patent with drawings of how this one works. The museum may know the maker. Amazing how many variations there were.

[TerryWerm]

I looked high and low for a manufacturer's name but came up empty handed. I also inquired in the museum, staffed only by an elderly life long resident. All she knew was that it came from one of the mines in the area.

I sat down and did some quick sketching using a CAD program that I have and I have the basics figured out. Getting the piston valve to seal up inside the rotating directional sleeve would be easy, just using rings like any other piston valve, but getting the outside of the sleeve to seal up without binding would be another challenge. Any leakage there would allow live steam to escape directly into the exhaust. But, if designed properly, the sleeve/valve combination would be surrounded by steam around approximately 60% of its surface area. If the sleeve was machined to fit in the bore inside the steam chest with a bit of clearance when cold, it would be possible to get it to fit fairly well when it is hot.

Despite the things that I've figured out about it, I am still hoping that someone here has seen this type of reversing valve before and can share some information.

[crueby]

Found a couple of possible ways the valve could be done in these two patents, PDF's attached...
Chris

[TerryWerm]

Chris, I believe you hit the jackpot, and after careful review, I believe the earlier patent was used on the engine in question. However, it is possible that this engine may have been the inspiration for the inventor named in the later patent. The engine was in Leadville, and the applicant of the second patent was from Leadville, and he had no model to present along with his application.

Coincidence??   Maybe.    Probably.  Either way, anyone who might know was buried long ago and we will never know for sure.   

[crueby]

Glad that helped! Google has a patent search engine that is quite good, I have found lots of interesting info that way.