Boiler design and Green Steam Engine

You can see that somebody made an SES for 2000 dollar. Still a bit much for me but mine would be smaller. About the cert. rules, he didn't have to certificate it but rules are different everywhere.
http://www.steamautomobile.com/ForuM/read.php?1,13015,13016#msg-13016
2/5 down the page.
Google is certainly not my friend when it comes to finding tubing prices.
One of the links in that discussion shows steel tubing at 4dollar per foot, thereabout. Pretty expensive stuffs.

 

Sigurd,
you MUST certify even if you do not want to use it in the public! Screw fittings usually get no approval. 10k € is the absolute minimum for a simple coal or oil fired "scottish" type of steam launch boiler, the most common and simple type.
some links:
http://www.deutscher-dampfbootverein.de/flohmarkt/index.html
http://www.steamboat.org.uk/
http://www.prestonservices.co.uk/boilers.htm
just ordinary, old fashioned stuff
the boiler type you are going for is far above those rates.

EDIT: did just read across the site you linked to, but even they are in the 10k$ region for homemade units without cert. needed!
In EU as in most countries you MUST. And believe me I have a clue about this subject, I had about 15 Boiler revisions and three new built boilers, in my museums ships.

Regards
Richard

 

huh? I just told you, 2000 usd - 70 bar, 540kg/hour. read my last post, and the discussion (chuk is the one with the SES)!

(edit: You removed the part about screw fittings not getting approval?) What, screw fittings less reliable?

I think the old fashioned stuff is costlier, it doesn't use water tube, means a lot of welding, and it has much more volume so is much more dangerous when exploded.

Edit - thanks for the preston link. They have some injectors that look appropriate. (the boilers all look like they would sink my boat)

 

I thought about a separator. As per the lamont, there
is an economizer, a generator and superheater coil.
However, this separator replace the normal superheater
- though it doesnt have to.
There is an inner and an outer coil. These need not be
cone shaped as in the rendering. Most probably they
could be cylinder shaped as well.
There are several connecting pipes between the two
coils.
Steam from the generator is admitted to the bottom of
the inner coil. Any water present will be forced
through the connecting pipes, due to gravity and
centrifugal force. Once inside the outer coil, it
will run downwards due to gravity, and down into
a chamber which will contain the water level meter.
The water from the economizer will also be admitted
to the top of this chamber.
On the bottom of the chamber is an exit to the
recirculation pump, pumping water to the generator.
Steam to the engine is taken from the top of the inner
separator coil.

I think this separator might separate quite reliably,
even with accelerations and at odd angles.
It also has a low volume, and is made from light tube
and fittings.

 

Sigurd I agree that there are many intelligent approaches possible, and some well proven too, I just do´nt see any sense in such a steam engine installation in a light boat.
It might be possible to make a boiler at half the amount I estimated, but even that is far above any lightweight Diesel. Let alone the annual inspection.
Do´nt get me wrong, I´m not fighting the principle, quite the opposite. I am going to install the very same engine as a generator in a off grid retreat on Bali. Solar powered, low pressure, much similar to PAR´s installation. Just different battery management and sizing, cos off grid.

Be shure I would be the first to follow a senseful, new steam technology for yachts. I was preserving steamers for some 15 years, not for nostalgic reasons only. And you know me as a promoter of steam technology, but
for safety reasons, I´ll never recommend a "cutting edge" boiler installation without class. approval. Remember, one litre of water gives 1,600 litres of steam and you will have several litres circulating.
If your vessel capsizes, or a wave enters the fire grate / burner, which does´nt seem sooo unlikely, every sort of boiler will explode instantly.

Regards
Richard

 

Either you or the people who did build a SES boiler for 2000 (there is more than one in that thread that agrees it is a realistic price) don't know what you are talking about - or more likely the difference stems from sourcing different parts, different paperwork, outsourcing work etc.
Repeating myself, that is a very much larger boiler than I need, which means the tube will cost much less and it will be much lighter.

Glad to hear you are going to try to make the engine work.
What do you intend for the cylinder support universal joint?

A diesel is not really comparable in this (my) situation because it cannot burn wood. A producer gas driven petrol engine is the easy alternative. It will be noisy, and includes a thousand parts, including a gear train. A small petrol as a concequence is not very reliable, has a short life span and often repair requires some obscure hard to find part. As of now I have got a 6hp outboard that does a good job. "Gasifying" it might require a means of lubricating the cylinders - probably not very difficult.
I suspect the torque of the GSE could be multiplied without adding a lot of structure. This would make large, efficient propellers possible with no gear train. Flapping propulsion seems also extremely well suited to steam cylinders.

I heard what you said about the heat and size. I understood it like a high pressure boiler (which means higher temperature water) will be smaller and lighter for the same power. I don't see why the principle of the Green engine is restricted to lower pressure - pipes, valves, fittings and cylinders would have to be stronger. Maybe there are more issues like water hammering in the cylinders, lubrication requirements etc. that I know little about.

Your point about the cold water shock on the hot pipes is a good one, which needs to be properly adressed. Obviously the air intake will be ducted to prevent it. I suspect an ICE will die just as much if you pour water into its cylinders while running - but they probably have worked out how to prevent it by clever ducting. Quite unrelated, I used to have an old 6hp 1cyl crank started yanmar diesel. One time the boat sank. When I had hauled it up and pumped the boat, I cranked it up without further ado (there is a decompressor on these engines to make cranking easier). The first few turns, it spitted out the water in the cylinders, then it started. I don't remember if I drained the sump first or not. Seem to remember it spitted some water from the sump overflow too. I like those diesels.

 

I have not found out about the class. approval yet. Have sent a request to DNV.
About the water volume, I think as little as possible would be nice but i cannot estimate how much. The SES used finned tubes, decreasing the volume, and also I don't think it had any high pressure reservoir. If I need one, I can probably use more small dia tube, which will slow the expansion after rupture. So the expansion won't be faster than opening a valve full tilt to the atmosphere. It should be possible to test this by filing a weak point in the tube, fire up the boiler and leave the area? Repeat until it blows and see the amount of destruction.
Adding forced circulation will reduce the needed economizer area so there may be even less volume.

For the water level sensor, going to an indicator and the feedpump/injector control cirquit, electrodes inserted in the pipe is what I am thinking about now. Resistance between the electrode and steel pipe will decrease when submerged. I do not know if electroplating of the electrode is a concern, there was some trick mentioned to avoid it - using an AC "symmetrical source current wave" - not sure I understand the principle of that. There would have to be a sense current going there and there could be issues with galvanic corrosion of the pipe if it is not properly done, but these things are used in commercial boilers. For reducing false reading due to accelerations and temporary odd angles, sloshing should be inhibited. Maybe steel wool inserted to parts of the tube.

For controlling a feedwater injector, I am also reading about an interesting concept where water overflow will clog the injector.

For adding recirculation to the SES boiler, I am looking into canned electrical pumps. Solenoid pumps also seem good for this? Also it just occurred to me that perhaps a pop-pop engine with check valves could be used for this purpose.

 

Does Harry Schoell's cyclone engine improve on other steam engines?
http://www.cyclonepower.com/works.html
(website compares it to internal combustion engines, but it's a steam engine, yes?)

 

As someone who works with both water tube and fire tube boilers I cannot visualize any possibility of their safe utilization for power on a pleasure craft under at least 60 feet. Even then management would require highly skilled professional licensed management. Home made boiler equals high incidence of fatality or severe permanent disability. Amateur management of boilers equals high incidence of fatality or severe permanent disability . Earlier in this thread I saw reference to 100 pound pressure steam. I've sat alongside of a man that had flesh vaporized to the bone after a mere second of exposure at that pressure. Our Provincial Boiler Regulating body regularly issues investigative reports of fatality and severe injury incidences within its jurisdiction. I have been told that all North American States and Provinces have fatality and injury investigative reports readily available for public access. Anyone considering boiler usage at any level, let alone marine application, should review some of those reports before exposing themselves or others to boiler use.

 

You have forgotten the hundreds of steam launches built every year?

 

To some extent we all live in closed universes. I've never seen a steam launch. It's possible that you have never been upon a well site where mobile boilers are in daily use. My world is filled with boiler fatality reports and on the well sites themselves, I meet minor burn victims at least once a week. I meet major burn victims about once a season.

From my perspective ownership of a steam powered boat would be comparable to ownership of a race car.If you are aware of the risks and enjoy the taste of death it is your choice.

 

I've just returned from examining steam launch engines and launches advertised for sale on line.As someone who loves boiler operation I would rather take my chances on the local oval dirt track raceway at 160 MPH than travel in the steam powered launches I saw advertised.

 

And they will be very reassured.
The Coast Guard never reported any accident with the countless small steam launches, nor from steam enthusiast demonstration at different gathering.
Several of these delightful steam launch is right here in Maine, work like a charm, go silently and take the bad weather we have in North Atlantic pretty well.
They are from 18' to 40'.
It seams very simple engine and boilers, and the owners very knowledgeable about small steam propulsion.
Non of these boat are light, that is not possible.
We are lucky to have in this forum Richard. Is a professional on steam engine, we should listen at what he said, we can learn a lot.
Myself first.
Daniel

 

As I indicated earlier I love steam but I would never stand within 50 feet of an antique steam engine being started or brought up to pressure. After it had been brought up to pressure for about 20 minutes I might come within 20 feet of one if I had a clear exit path.If one of the launches I saw advertised was on water I wouldn't come within 100 feet of it. I'd enjoy watching it from a distance of 100 feet if I was adequately sheltered behind a sturdy oak tree.

Having said that I also concede that we all have different risk tolerance personalities. Mine is a product of experience alongside many burn victims combined with a history of compulsory review of Power Engineering Fatality Reports. Some people love dirt track ovals while others love antique steam engines.

 

What a utter nonsense.

One steam related accident per week?

Steam engines more dangerous than cars on a race track?

Well, we know already, you as a oil spill engineer have a deep insight in such stuff............

We are safe and happy when we putter along in our steam boats and ships, because we know what we are doing.
You will be most probably not as safe and not happy, because you don´t know what you are doing.

But thats valid for every field you are tinkering on. Every single of your posts is jst another proof, you do many things, nothing right.