The Breakroom > The Water Cooler
Remember the "Green Steam Engine ™" ?
Dean W:
--- Quote from: Bernd on August 19, 2010, 12:51:29 PM ---
The reason for posting this subject was more to point toward the use of a Pressure Cooker as a boiler. I'm sure you read the thread on HMEM about the use of PC. Seems like all the experts tell you how dangerous they are and not to use them, but they never say why they should not use them. None of them seem to want to take the time to explain in more detail how to build a boiler and why they have all the saftey devices, plus the proper care and feeding of a boiler.
Bernd
--- End quote ---
Bernd, there have been a few explanations on HMEM on why NOT to use a pressure cooker. There are also a great number of threads
dealing with building a proper boiler, and boilers in progress. If you don't see what you want to know, go to the "Boilers" section and
ASK. There are a number of build threads there that go into great detail.
Dean
Bernd:
--- Quote from: Dean W on August 19, 2010, 06:23:26 PM ---Bernd, there have been a few explanations on HMEM on why NOT to use a pressure cooker. There are also a great number of threads
dealing with building a proper boiler, and boilers in progress. If you don't see what you want to know, go to the "Boilers" section and
ASK. There are a number of build threads there that go into great detail.
Dean
--- End quote ---
Dean,
I've gone back and looked at the boiler building threads. The first that comes to mind is Firebirds thread on building a boiler. A very fine thread on how to. And I believe was the first thorough thread on building a boiler. The second one that stands out is Dusti's thread of building a boiler. Interesting to see the stress analysis that he has done.
Now, I've been a model railroader ever since I can remember and always had an interest in steam. I also belonged to a live steam club for several years and got to see how the models were built. Reading up on steam engine explosions I've learned about the crown sheet and that it should be covered with water at all times. How do you know the boiler water is at the proper level? With the water sight glass, or try cocks, as fitted on the first boiler designs. I've also read about how a pressure releive valve is supposed to work on a working boiler. And I know that saftey plugs are screwed into the crown sheet so if the firebox gets to hot they will melt and doss the fire out.
Have I ever built a boiler? NO. But I believe I've read enough and have enough common sense to build a safe boiler and would know how to use it. What are some of my sourses, Hioroka's series on geared engines. Early magazine articles in Live Steam. A book called Model Boilermaking, Designing, making and testing by G.L. Pearce. And some others that I don't remember right now, plus the fact that I can ask questions on the forums about what I don't understand.
With all that knowledge at my finger tips I wouldn't consider myself any were near an expert.
Ok, now on to why I started this thread and why I've made the comment I have. I dug around and found what I was looking for. This is the question Karl (aka Zee) asked "If pressure cookers are not safe as a steam source (and I think any pressure vessel is to some degree unsafe)...then why? What are the dangers? I know even cooking can cause overpressure." In the thread "causing upset" reply #23. When I read Tel's reply (#27) I have to ask myself, "Dose he really know how much steam is generated?" I remember my mother canning veggies using a pressure cooker and my wife also uses one. So I'm familar with pressure cookers. Also I don't think that was a proper answer. To me any pressure vessel that is not being tended to while in use can and will be dangerous. So with that in mind would you stand next to me while I was using a pressure cooker to run a stean engine that will run on 15psi or will you stand next to my 1 1/2" scale live steam engine with the propane valve wide open heating the water while I'm off wandering around talking to other people? I'll bet you pick the live steamer, why? Beacuse you'll hope that I've built the saftey valves properly. How will you know if I did?
I'm sure you can see where I'm going here. I'm not trying to start a heated debate but hopefuly some understanding. To me any boiler should be attended to while in operation. It should be run within it's limits and the person running it should understand the how's and why's.
Now here's something of interest if anybody wants to understand the anatomoy of a boiler explosion. I believe it's a must read. I'm sure that many in the USA are familar with. Read the report and then look at the pictures. These are the kinds of answers that should be given when boiler questions come up as to their saftey.
http://www.dli.mn.gov/ccld/BoilerIncidentsHobby.asp
http://www.dli.mn.gov/ccld/BoilerIncidentsHobby1.asp
Here's a boiler that should have been safe, but............
So my question is which pressure cooker is safer the one on the stove or the one with wheels on it?
My answer to that would be neither if boiler saftey is ignored. Problem is you can't teach common sense. That's all it takes some times is a bit of common sense and understanding what your working with.
And if you still think pressure cookers are unsave, take a look at Elmer Verbergs engine number #26 "Live Steam Boiler and Engine". Take note of his fill plug. Also I believe the engine is designed to run on about 5 to 10 pounds of steam.
For those of you who don't have drawings they are available here, go to http://john-tom.com/ElmersEngines/25_26_WobblerBoiler.pdf
That's it for now.
Regards,
Bernd
Note: Just found another report of a boiler explosion that happened in Pennsylvania in 1995 on a tourist line. Interesting read, also recommended for the boiler minded.
Ammended to add link to report. http://www.ntsb.gov/publictn/1996/sir9605.pdf
kwackers:
--- Quote from: Bernd on August 19, 2010, 09:25:06 PM ---.....
And if you still think pressure cookers are unsave, take a look at Elmer Verbergs engine number #26 "Live Steam Boiler and Engine". Take note of his fill plug. Also I believe the engine is designed to run on about 5 to 10 pounds of steam.
.....
--- End quote ---
Phew! When I read pressure cookers I had visions of people trying to get 80psi out of them!
Bernd:
--- Quote from: kwackers on August 20, 2010, 08:23:23 AM ---
--- Quote from: Bernd on August 19, 2010, 09:25:06 PM ---.....
And if you still think pressure cookers are unsave, take a look at Elmer Verbergs engine number #26 "Live Steam Boiler and Engine". Take note of his fill plug. Also I believe the engine is designed to run on about 5 to 10 pounds of steam.
.....
--- End quote ---
Phew! When I read pressure cookers I had visions of people trying to get 80psi out of them!
--- End quote ---
That is one of the problems. A pressure cooker is designed to operate at no more than 15 psi or perhaps 20 psi. The pressure vessel needs to be designed for how much you will need to power your engine. You can't take a pressure vessel or boiler design that gives you only 20 psi to operate an engine that needs at least 50 psi to run. Another factor is how fast will the boiler turn water into steam to do any useful work.
A boiler needs constant attention to make sure that everything is functioning properly and that it is run properly within it's limitations.
Bernd
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