I want to build a steam vacuum engine that would operate similar to a flame eater. Instead of sucking in a flame it would suck in steam vapour. The steam vapour would condense in the cylinder creating a vacuum. There would be no pressure in the boiler, just a rich steam vapour at atmospheric pressure. I don't expect it to produce a lot of power, just enough to keep running reliability. If no one has built anything like this I am going to attempt to build one of my own design.
Steam Vacuum engine: anyone built one?
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Klaus
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Hello,
i read a article about a atmospheric steam engine in a german model magazine. If i remember had this modeler problems with the physics because of scale. The steam engine was the first in germany. The engine cool down to quick so he had to add a electrical heating at the cylinder. If you want i can search for this article!
Klaus
i read a article about a atmospheric steam engine in a german model magazine. If i remember had this modeler problems with the physics because of scale. The steam engine was the first in germany. The engine cool down to quick so he had to add a electrical heating at the cylinder. If you want i can search for this article!
Klaus
Gedeon Spilett
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This the principle of the Newcomen Atmospheric Engine around 1700 ! It worked.
http://www.egr.msu.edu/~lira/supp/steam/
I'm not aware of a working model at the moment
http://www.egr.msu.edu/~lira/supp/steam/
I'm not aware of a working model at the moment
A late response, but I don't think that anyone seems to grasp what n4zouis talking about.
We're not thinking about a small scale replica of Newcomen's engine.
We're thinking about an engine that operates similar to a flame eater.
Meaning a steam-to-vacuum engine which has a crankshaft assembly.
A small, open, atmospheric boiler (carburettor-look, with a large chamber for the boiling water) would be mounted, not far from the cylinder, and with each downstroke the piston would draw in a mixture of air and steam, which condenses and causes a vacuum, after the inlet valve closes.
I think that anyone with a flame licker engine could easily experiment with a basically "tin can" setup like this.
Steam might even be better than hot air, to drike a vacuum engine, since water vapour causes a more powerfull vacuum.
(Boil some water in a tin can, and then shut the can off, and put it in a cold water stream: It will implode.)
@ Klaus: Once in the cylinder: The faster the vapour cools down, the better it is.
We're not thinking about a small scale replica of Newcomen's engine.
We're thinking about an engine that operates similar to a flame eater.
Meaning a steam-to-vacuum engine which has a crankshaft assembly.
A small, open, atmospheric boiler (carburettor-look, with a large chamber for the boiling water) would be mounted, not far from the cylinder, and with each downstroke the piston would draw in a mixture of air and steam, which condenses and causes a vacuum, after the inlet valve closes.
I think that anyone with a flame licker engine could easily experiment with a basically "tin can" setup like this.
Steam might even be better than hot air, to drike a vacuum engine, since water vapour causes a more powerfull vacuum.
(Boil some water in a tin can, and then shut the can off, and put it in a cold water stream: It will implode.)
@ Klaus: Once in the cylinder: The faster the vapour cools down, the better it is.
Gedeon Spilett
Well-Known Member
This what the Newcomen engine do, breathes steam, then condenses it, and the vacuum allows the return to the initial position.
A 'classical" flame eater engine can't stand the condensation, the drag is too high, and the engine stops immediately. This is well known and always occurs at the first heat with a cold engine, and drives the newbie to desperation...
Maybe that can be overcome if more power is generated with steam, but condensed water should be removed rapidely too, and this requires changes in the design of the models I know.
A 'classical" flame eater engine can't stand the condensation, the drag is too high, and the engine stops immediately. This is well known and always occurs at the first heat with a cold engine, and drives the newbie to desperation...
Maybe that can be overcome if more power is generated with steam, but condensed water should be removed rapidely too, and this requires changes in the design of the models I know.
Ehh.. If I'm informed correctly, the newcomen engine doesn't "breathe" steam, since the water for generating steam is basically heated in an enclosed environment, while beïng condensed by a water spray. It's not an "open system", like the one I have in mind, in which air is drawn in by the engine, through an open boiler, while picking up steam. (Hence carburettor style)
[ame]http://www.youtube.com/watch?v=9GqVQPMCtY4[/ame]
And on top of that, the Newcomen engine did not have an autonomous cycle.
Every move of the engine, had to be started by the operators.
What I'm basically talking about, is a reversed Watt engine.
Condensing steam creates a more powerfull vacuüm than cooled air.
And a somewhat larger overpressure valve, should be sufficiënt to get rid of both overpressure, and condensed water.
Ofcourse under the condition that the valve is mounted at the (absolute) lowest point of the cylinder.
So a lying- or an upside-down configuration would be pretty much necessary, in order to drive excess water off via the valve in the cylinder head.
Even a plastic cylinder and (epoxy?) piston would be a possibility, since the working temperature of the cylinder would be beneath the boiling point of water.
RManley
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jwcnc1911
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I would like to encourage you on a novel idea! I'd also like to state the obvious... steam condenses (obviously that's the idea for the engine)! Make provisions to get the water out. Maybe an "upside down" poppin type or a second valve or set of valves to evacuate condensate. The water has to come out some how or I assume the cylinder will fill up with water.
Good luck! I'll be following your build.
Good luck! I'll be following your build.
Well, all classic "flame eaters" already have an overpressure (check-) valve to let out abundant air, at the end of the "up"-stroke.
The same valve, although a bit larger to overcome the extra drag caused by fluids, could be used to drain water from the cylinder as well.
It could even be transported back to the atmospheric boiler without using a separate boiler feed pump!
I haven't started yet, and it might take a while to do so, but if/when i start, I'll surely report it here, in a separate thread.
Thanks!
Gedeon Spilett
Well-Known Member
ok, I agree with you for Newcomen, too many shortcuts causes errors at the end.
For having made a lot of vacuum engine, I can say that the drag due to water is a major problem in your project.
But it seems also true that with steam, many problems are eliminated as : excessive stress due to heat and the use of heat resistant materials for longer run, soot deposits in the cylinder carbonization of the oil etc. ...
The use of many new materials is now possible with operation at lower temperature. Probably you have to start from scratch instead of modifiing existing engine plans.
I will look at your model with the attention it deserves
For having made a lot of vacuum engine, I can say that the drag due to water is a major problem in your project.
But it seems also true that with steam, many problems are eliminated as : excessive stress due to heat and the use of heat resistant materials for longer run, soot deposits in the cylinder carbonization of the oil etc. ...
The use of many new materials is now possible with operation at lower temperature. Probably you have to start from scratch instead of modifiing existing engine plans.
I will look at your model with the attention it deserves
What drag?
I mean: The vacuum is more powerfull in order to overcome any aditional drag (look at how that oil drum inploded), and on top of that, the condensing water might even improve the sealing between the piston and the cylinder a little bit.
And the Newcomen-engine.. You can point out a lot of faults in it (It was the worst for beïng pretty much the first.), but not that it suffered from excessive drag.
The major question that I'm asking myself, is: Will the steam condense fast enough to make an autonomous cycle possible?
Will it cool as fast as air does?
Exactly. I, for example, would not be easily tempted to build a high pressure boiler myself. Too dangerous, while the prefab boilers rarely meet my expectations in shape and/or size.
And spinning engines on air, for me takes the fun out of them.
To me, steamers are fire breathing creatures, period.
Even when they might be odd.
Well, I'm still brainstorming.. Not making any promises yet.
AussieJimG
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It sounds a bit like a Stirling (hot air) engine modified to use water vapour as the working fluid in an open cycle instead of air in a closed cycle. I can feel ideas developing and will be following your progress.
Jim
Jim
More can be seen right here: http://www.homemodelenginemachinist.com/f26/steam-eater-20696/
I too, would like to encourage you on a novel idea! I want to take issue, not with you but with the author of the previous post. The best part of using steam is all the different forms one can choose from. Superheated steam, at near atmospheric reduces specific volume when it cools down without necessarily condensing. That is similar to using any kind of hot gas such as air in the case of the original engine design. Steam only condenses (changes physical state) at one specific temperature and pressure combination for the amount of latent heat onboard. The sensible heat present (that which we know as temperature) does not change during the change from vapor to liquid! Gp read up on the differences in the kind of heat you intend to use and design to it.
Unkaderl
Unkaderl
The use of superheat in steam turbines is one of reducing the superheated steam from one level of sensible heat to a lower one. Condensation is avoided in the engine because it would destroy the engine. in these modern engines the steam is condensed down stream of the turbine in a surface condenser. when it does the pressure drops to almost absolute vacuum. In old fashioned locomotive engines the steam was not condensed either. Water is incompressable and that is always a very bad thing inside an engine. steam is nearly always superheated beyond the point of condensation after the power stroke.
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