Steam Engine/Correspondence
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Steam Review
May 2, 2011 to Tom Kimmel of SACA
I have been working with Marcin Jakubowski of the Open Source Ecology project lately to update a design for a steam engine. Marcin tells me that he had some discussion with you back in 2009 on an earlier version of this engine.
To refresh your memory, OSE is trying to develop a prototype steam engine that is:
- Easy to fabricate from stock materials (steel, cast iron, perhaps brass, etc).
- Modular such that it can easily be broken down for maintenance and repair
- Stackable so that multiple cylinders can be ganged to a common crankshaft for more power
The current design is similar to the older one (single action, uniflow), with the following improvements:
- Piston activated bump valve
- Steam entry at end of the cylinder, rather than the side
- An oil sprayer for lubrication
- A water drain to remove condensed water
We would welcome any comments you might have about these updates to the design. Several drawings can be viewed at http://openfarmtech.org/wiki/Steam_Engine_Design and I am included the mid-cycle drawing as an attachment. The design of the bump valve was influenced by comments on the SACA forums - the "chinese hat" shape that is self centering and less likely to be damaged by the bump pin.
Some questions to consider:
- How likely is this bump valve to work? What improvements could be made?
- We at thinking of making the bore 4" in diameter, in part so that we can use off-the-shelf piston rings. What impact does this have on the performance/function of the engine.
- Will the oil sprayer shown be sufficient to lubricate the engine?
- Should we leave the crankshaft end of the cylinder open or close to to keep dirt out?
- If we put a hand crank on the flywheel, would that be sufficient to start the engine?
- There is a cylinder liner shown in blue, what material would you suggest for it?
- What are we missing or should consider?
Tom replied on May 3, 2011
May 3, 2011 Dear Mark,
I am sending this message on to another club member who may reply with some comments. If anyone other than me responds they will know more than I do, so listen to them. Secondly, you are invited to come to my shop and look at steam engines and take them apart and look at my extensive blueprint collection. I suggest that a little research will go a long ways when designing steam engines. Thirdly, there is a great need for a manufactured steam engine. For stationary purposes it does not have to be light or small, just cheap and reliable, which makes the design and manufacture much easier.
And to answer some of your questions:
A hand crank will get the engine started rotating the right direction. Off the shelf re-built starters should be available that are cheap and reliable so making provision for a flywheel with teeth on the outer edge, in other words, using a used IC engine flywheel may be the better way to go. You will want a pretty good sized flywheel for this anyhow because of the high recompression on the up-stroke.
The cylinder liners should be cast iron and they should be an easily available one. There are custom made ones from India available from a company in Texas and on a good day I can find that address. The ones that the people who know what they are doing use are from a re-build kit for a small International four cylinder tractor. For a couple of hundred dollars you get four sleeves and four pistons. This is what Jim Tangeman used and what Art Gardiner used. They are the two smartest people I know. Jim took a six cylinder in-line Ford engine and cut the block off sideways from the crankcase and then turned it upside down and cut it in half. This left him with a 3 cylinder engine and a store bought crank and connecting rods. He then bolted these cylinder liners onto some type of a frame and had a very good and reliable boat engine that is still running. Art used the liners in a 3 cylinder Outboard motor and made a 100 hp engine for the dragster that Chuk drives. This way you have a cylinder liner and a piston and rings that all fit.
With regards to the bump valves that you are using, these are the same design more or less as the MSS people used on the Hirth snowmobile engine that is in the VW they made. The difference is that the sealing surface was machined spherical instead of conical. The advantage of that design, yours and the MSS one, are that the pin bashes against the part of the valve that is not part of the sealing surface, because the bashing deforms it. You can go with a round sphere if it is silica nitride from McMaster Carr. The true Chinese hat design done by Jay Carter, the next smartest person I know, is no where like the design you have. Therefore I suggest a little more research there.
An open or enclosed crank case is not a serious issue if we are talking stationary power. You do not want to get caught in the mechanism on the one hand and you want to watch it go around on the other hand, so it is a toss-up. Jim went with an open crank.
Lubrication is a serious issue and I suggest that smarter people than myself be asked that question.
The answer to your first question is that the bash valve design is a pretty good one and it will work as long as you have enough area for the steam to flow through. As for going with a 4” bore in order to get rings, I suggest that rings are available for every sized bore there is in the world, so the precise diameter is not an issue as far as rings go. What you will want is a good piston and connecting rod and the issue is how to get lubrication to the bearing at the little end. This is why most people go with a two cycle engine because there are needle bearings there. I would ask Jim T. what he used for lubrication at the little end.
People are working on all kinds of exotic materials, such as nitride coating of the cylinder as they do in drag racing to minimize friction and wear and others are going with carbon pistons in order to get around the lubrication issue, but the long term reliability of the carbon piston is unknown. Therefore I suggest that this engine start with conservative materials.
I suggest that you take a long look at the way the MSS people made the exhaust manifold for the uniflow engine. Theirs’ was the most clever and easiest and smartest of all the designs I have seen and it needs to be designed into the engine from the beginning. And finally I suggest a long day visiting Bill Ryan up north of Chicago who has years of experience making bash valve engines that go like the wind for at least short periods of time. I am going to be looking at a well-developed two cylinder double acting uniflow using poppet valves and a sliding cam shaft with castings made by a fellow over north of Detroit. I find it easier to use other people’s work than it is to do my own.
Sincerely, Tom Kimmel
White Cliffs Solar Thermal Power Station
May 2, 2011 to Mal Williams of Australia NSW DOE
I am involved with a project to build a small, scalable steam engine for farm use. I came across an article by Erik Rossen (http://www.rossen.ch/solar/wcengine.html) that commented favorably on the solar steam engine developed by NSW DOE back in the eighties. Mr. Rossen mentioned that you might have an electronic form of the report, "White Cliffs Solar Thermal Power Station", Design, operation, and results. 242 pages, 1991. If possible, could you send me a copy? I'm very interested in the diesel engine conversion and the use of bump valves.
I am doing this work for the Open Source Ecology project (http://openfarmtech.org/wiki/Main_Page). Our intention is to design and prototype a set of 50 tools (the Global Village Construction Set) that would enable the development of high standard of living and local economy at a village scale in virtually any setting globally.
Old Messages, 2009
2000 to VK Desai of Tinytech Plants
Letter to VK Desai of Tinytech Plants (Tinytech are an Indian company that make steam engines)
Dear VK,
Can you share your knowledge of steam power with us?
In order to make our solar turbine a success, we need to build the steam engine at low cost - in house. If I do my own labor, use our machine shop, and use casting in house, then the price for the engine parts should be about $150 for a 3 hp engine. Do you think that is realistic?
Please share with me your basic design. Simple drawings on the back of an envelope would do. I am smart at studying design. Please just give me the essentials and material specifications.
Please respond, or put your notes up directly at:
http://openfarmtech.org/index.php?title=Steam_Engine_Construction_Set
If you have any pictures of steam engines in fabrication, please share.
Sincerely,
Marcin
2009, From nick to Mike Brown
Mr. Brown, I have been working lately on developing a simple horizontal uniflow steam of 3" x3.5" bore and stroke that is controlled by an electronic solenoid valve and a small programmabale logic controller. My full intention is to power this engine with a gasifier monotube style boiler and utilize the exhaust in a 750 gallon thermal storage tank for home heating purposes. In my research in this project I found reference to Skip Goebel's work through your site.
that Skip Goebel may already be building a boiler of similar design, if possible could you give me his contact info? I would also be interested to know if you have given any thought to developing an electronically valved steam engine? I intend to try an asco 1/2" direct acting steam valve that claims to cycle at 800cycles/min for a million plus cycles. I intend to run my engine at 100rpm which in theory may give my controll of the cutoff ratio in increments of .25. This obviously will not be efficient but I want to try the concept first. Perhaps you know more about what this actually would take? In any case I do appreciate your time to read this email and I hope you keep up the good work in small scale steam power development.
seek out mike brown steam engins on google
Response from Mike Brown Steam engines
Nick,
Skip Goebel is in Peru, do you have the DVD he did on building a prototype boiler?
I doubt if your solenoid valve will last six months on a steam engine.
Sorry, we don't get involved in other people's engineering projects (we average two emails like yours a day).
Best wishes, Mike
Skip Goebel Sensible Steam Peru s.a.c. Lima, Peru Lima 51 996 984 741 US· 559 922 2410 www.sensiblesteamperu.com
January 26, 2009, to Skip Goebel
To: info@sensiblesteamperu.com Sent: Monday, January 26, 2009 10:22:16 AM Subject: Wood Fired Monotube Boiler
I came across your site in studying the works of Skip Goebel in home powered steam systems. I intend to build a 3kW cogeneration DC system for home and experimental use. All my research leads me to conclude that Mr. Goebel may have pioneered this idea the furthest and I would be interested in purchasing any information that he has made available on the subject.
I'm not unfamilar with steam, I worked 2 years as Mechanical Engineer at a 400MW coal fired power plant, but am now envisioning working on something a little more decentralized. In any case I strongly feel the case for more self sufficient energy systems is here and given the fuel flexibility and reliability of the steam engine I wish to pursue this idea further. My plan is to construct a simple monotube fired 3kW mechanical valve steam engine to charge my DC battery bank and thermal storage tank. After I am comfortable with this design I would like to investigate the potential improvements of using a low cost programable logic controller for boiler control. Additonaly I am looking for a a high speed durable solenoid valve and the right steam valve to investigate the possibility of electronically conrtolling steam into the engine.
Right now I am thinking that I could use a control loop to continously vary the cutoff ratio of the steam engine for my governor. This would optimize efficiency by running with the lowest allowable cutoff ratio. In any case it seems at least feasible to think that in the future steam engines efficiencies can be improved by better steam control which is one more reason that this technology attracts me. So if Sensible Steam has any information avaialable by Skip Goebel on steam engine system construction and experiences with it I would be very eager to hear more about it how to get it.
January 31, 2009 to Alan Nelson
Sent: Saturday, January 31, 2009 12:30 PM To: Alan Nelson Subject: Atkomatic Solenoid Valve Response Times
Alan, I am looking at your atkomatic line of solenoid valves and would like to know if you offer anything suitable for the a 2-way continous duty pulse cycle valve for saturated steam up to 600 deg. The valve also needs to have a very fast response time of 75ms for open and 75 ms for close. Is there anything in the atkomatic line that might fulfill that response time requirement? If not do you know what other type of valve I might try looking at for that desired response time? Thank you for your time.
Regards, Marcin Jakubowski
Response from Alan Nelson
We do not have any valves capable of handling 600F steam.
Alan Nelson, Fluid Process Control Corporation