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Re: 7HP Square Cylinder Dake? - Is this legit steam?

Posted: Sat Jul 08, 2017 5:24 am
by PatJ
I am a bit late to the game here, been busy with any number of things, and actually forgot that this forum existed until for some reason it popped into my head tonight and I remembered to check it.
Life has been too busy for me the last few years.
Luckily I was able to remember my username and password.

My dad built a Dake model, and I made a set of model Dake plans that are pretty accurate.

This engine was successful commercially for special applications such as winches, work in mines, hoists, and a few other special applications.
The Dake design is very close to a Roots design patent that was issues perhaps 25 years earlier (almost identical, with some minor modifications, but I guess enough modifications to get a new patent).
The Roots and Dake designs are shown here:
http://www.aqpl43.dsl.pipex.com/MUSEUM/ ... square.htm

The benefits were that it was a totally enclosed engine when most other steam engines had open crankcases, and thus the popularity in a dirty mine.
I have seen them used as an anchor winch on a boat, I think on this site, and again the totally enclosed design would be very helpful in saltwater on a boat deck.

The clearance between the pistons (2) and the crankcase can be adjusted by removing shims from the crankcase cover.

The engine really has very few parts, and is much easier to make (assuming you can cut and lap a flat surface) than a traditional steam engine with crosshead guide, eccentrics, and all sorts of other parts.

I have started the patterns for a model of this engine, and the crankcase measures 5" across.
I will be cast the engine in either aluminum or perhaps gray cast iron if I get lucky.

The drawings for the model are located here:
http://www.classicsteamengineering.com/ ... opic=946.0

The Dake can easily be reversed if it is fitted with the reversing valve, even while the engine is running.
The reversing valve can be seen in the 3D model in Reply #2 and 3 here:
http://www.classicsteamengineering.com/ ... opic=929.0

Re: 7HP Square Cylinder Dake? - Is this legit steam?

Posted: Tue Jul 11, 2017 11:26 pm
by cyberbadger
PatJ,

Very cool. I built 50% of a wood steam engine model that would run on compressed air from plans I bought a long time ago that look sort of similar but it wasn't a dake (had a square cylinder though).

There are definitely all sorts of nich/oddball steam engines and equipment out there - but the Dake had me confused more so then usual with the square cylinder.

Seems like it was a compact form that found use in certain tasks.

-CB

Re: 7HP Square Cylinder Dake? - Is this legit steam?

Posted: Fri Jul 14, 2017 12:40 am
by PatJ
The Dakes were robust and very functional engines, but I am not sure I would want to hook one up to a continuous load.

One of the other applications for the Dake was as steering engines to move the rudders on large ships.
The Dake was perfect for this application because they reverse so easily and quickly due to their low rotating mass, and also being totally enclosed and compact enough to fit in a wheelhouse.

Its a fascinating engine, and while at first glance it seems rather a Rube-Goldberg device, they are quite functional in sizes up to 30 hp.

The cons of the engine are that there was no way to very the cutoff other than to change the inner piston to a different port arrangement, and the wear on the pistons was not uniform, with more wear towards the outside of the pistons, and less wear towards the inner part of the inner piston.

I had to disassemble one to figure out exactly how it worked.

The Dake reversing valve looks exactly like a Westinghouse locomotive air brake valve; engraving attached.