Author Topic: Developing a Small Steam Plant  (Read 523 times)

Offline gary.a.ayres

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Developing a Small Steam Plant
« on: September 09, 2019, 10:37:18 PM »
Hi.

With my 3 inch boiler and 12 mm oscillator now finished, the next step is to incorporate them into a properly finished little steam plant. The boiler is loosely based on a design by Stan Bray, and the engine on a design by Steve's Workshop, but I have taken plenty of liberties with both.

Here are all the components of the plant that I currently have:



Three interchangeable burners (pressurized kerosene, pressurized alcohol, gas), hand pump for boiler feed, boiler stand, engine and boiler.

My plan is to bring together all of the components of the plant and experiment with layout before looking for a base board, so that I get the size of the board right.

In addition to the above, I will need a water reservoir (currently in progress) and I'm also considering a steam separator for the exhaust (perhaps combined with a feedwater pre-heater, and possibly route the exhaust up the boiler chimney), an inline lubricator of some kind for the engine, and maybe even a very small generator and lamp post.

However, I don't want to go over the top, so I'd welcome your feedback on whether you think that's excessive for a plant this size. Equally, if you have any suggestions for anything else that I might add in that isn't mentioned above, please feel free to say so, as it's all part of the fun.  :cartwheel:

Cheers,

gary

Offline Ye-Ole Steam Dude

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Re: Developing a Small Steam Plant
« Reply #1 on: September 10, 2019, 01:41:48 AM »
Hello Gary,

Fantastic job that you have done with this entire project and some beautiful machine work on the parts.

Have a great day,
Thomas

PS, enjoyed your last video

Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #2 on: September 10, 2019, 09:12:43 AM »
Thanks Thomas - very kind of you.

All the Best,

gary

Offline MJM460

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Re: Developing a Small Steam Plant
« Reply #3 on: September 10, 2019, 12:43:41 PM »
Hi Gary, definitely not over the top.  I believe in always including a lubricator, a displacement type for steam, and an exhaust separator to keep the bench cleaner and dry.  And the generator and light will be a great and appropriate conclusion.  I have completed three plants like this, only one with a purchased boiler.

I have yet to build a feed pump.  I would like to say it is on the list, but definitely a “one day”.

It’s looking great so far.  Your artistic input shows in all your items and I look forward to seeing the progress on the complete plant.

MJM460



The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #4 on: September 10, 2019, 06:10:46 PM »
Thank you MJM!

I'm pleased you think my scheme is reasonable.

I have a feeling that I'll probably be looking for some advice from you (and others) along the way.   :)

gary

Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #5 on: September 11, 2019, 12:33:44 AM »
I'm thinking of incorporating a combined steam separator and feedwater preheater into the plant.

I'm sure that I saw some plans for one somewhere online once upon a time, but a search isn't bringing much up.

Keith Appleton has a short youtube series about building one, but I have a feeling it could be done more simply and cheaply than his (nice as it is with its cast end caps). I'd also prefer an upright one (his is horizontal).

Does anyone know of any plans for one? If not, I suppose I could just scratch build it using KA's as a guideline...

As with many things, the principle is simple enough but the devil is in the detail.

Thanks.

Offline MJM460

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Re: Developing a Small Steam Plant
« Reply #6 on: September 12, 2019, 08:37:52 AM »
Hi Gary, so long as you do not put a valve or other stopper in the stack or chimney the separator is always open to atmosphere and not a pressure vessel, so does not have to be designed for pressure.  You only have to design for function, along with your artistic input.

I have made them vertical with success.  The idea is that the engine exhaust enters high in the cylindrical side, preferably tangentially so the steam is forced to travel around the wall.  The heavier water droplets hit the vessel wall and tend to coalesce and run down to the bottom.  The stack protrudes inside below the inlet, so the steam flowing around the wall has to change direction again to go up the stack.  It needs a bit of vertical height below the end of the outlet to accumulate a bit of water and force it out the drain.

Ideally, the lower section should be conical.  As the steam moves down while whirling around the wall, it goes faster (conservation of angular momentum, like a skater spinning and changing posture).  Commercial ones sometimes use parallel corrugated plated to cause the changes of direction so the drops impinge on the walls and run down.

I have attached a picture of one, assembled in the steam plant, and another with the stack removed so you can see the part hidden inside.  (It started out shiny, but tarnishes incredibly quickly.)  And it works quite well.  The next one will have the stack vertical, something obviously slipped there.  I catch a bit of water from the drain outlet at first, then when it is all hot, the water ceases.  I get nearly no droplets out the top unless I have excessive carryover due to over-filling the boiler.  You can see that in my case, it is all about function with no artistic input!

I tried a horizontal one for a lower profile, also in the pictures.  The tube I had was too small for the body and it did not work.  I suspect not enough height to separate out the drops when the tube was horizontal, and I had even more hot rain than without the separator.  I have now obtained a larger diameter tube to try again.

If you want to incorporate feed water heating, I would suggest a coil for the feedwater water inside the vessel.  This would require a larger vessel than I have used.  But quite doable with say 38 mm or 50 mm or larger tube for the vessel.  And as many turns as you can fit, which is more easily accommodated in a larger diameter vessel.  The coil should be on the discharge side of the pump, as the pump will not like hot water.  I tend to use 3/16 tube for the water and steam lines, but 5/32 might be ok.  Of course if you want more heat transfer area, you can make a full on heat exchanger with many tubes, just like another boiler.

The heat lost to feed water will cause more condensation so you might need a bit more disengaging space above the coil.

MJM460

The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #7 on: September 12, 2019, 06:39:26 PM »
MJM460 -

As always, very clear and comprehensive.

It's a bit like the steam version of the cyclonic funnel on a dust extraction system.

Your post offers a great resource which I shall use as my guidline when I come to build the separator / preheater - it's a text in its own right.

The only change I plan to make is to route the exhaust from the separator up the boiler chimney, so I guess that rather than have a chimney on the separator there would just be a steam out pipe.

Re your point about your work being functional rather than artistic - I really like the look of your work. The robust functionality has an aesthetic of its own, and to me it has a real beauty to it.

As always, thank you for your input and the time you spend in offering it.

 :cheers:

gary

Offline MJM460

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Re: Developing a Small Steam Plant
« Reply #8 on: September 13, 2019, 12:42:52 PM »
Hi Gary, thank you, you are most welcome.

Yes exactly like a dust extraction cyclone.

You might need two sets of nut and tail connectors or pairs do flanges to connect the steam out pipe to the boiler stack connection, but yes, that’s the idea.

Hard to know how many turns to make the water coil, the water outlet can only approach but never equal the engine exhaust temperature which will probably be very close to 100C.  Making the coil will be good practice for that flash steam plant.  What ever you do will help your boiler steam output, but I expect the surface area of the coil will be the practical limit to how much you can achieve.  Five to seven percent might be achievable.

Looking forward to seeing how you go.

Thank you for your comments about my engines.  I enjoy making them, which is of course the whole idea.

MJM460



The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #9 on: September 14, 2019, 01:28:49 AM »
I look forward to interpreting your suggestions and applying them in practice.

They certainly give me a direction but no doubt there will be further discussion ahead...

 :) :ThumbsUp: 

Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #10 on: September 15, 2019, 04:59:37 PM »
Next up is the water reservoir. The body is cut from a bottle which was filled with Waitrose German Reisling which I had to get rid of before I could use the bottle  :wine1:.

I chose it because of its deep turquoise green. I have never seen another wine bottle of this colour, and I thought it would suit the feel of the plant. The top cover is a nice cast brass ceiling rose from an old electric chandelier courtesy of the charity shop. I enlarged one of the two screw holes to accommodate the pipe to the pump. The other can... er... serve as an air vent   :).

The underside of the rim had to be turned to fit the rim of the glass and there is still a bit more work to do on this to get a good fit. The stopper for what was the cable opening is made from an old brass door knob plus a spigot which I turned from brass so that it sits nicely in the hole. The stopper assembly lifts out easily so that the reservoir can be refilled in situ using a funnel. I'll look out for a nice brass or copper funnel rather than keep lowering the tone with one of my blue plastic ones   :)




Online Jo

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Re: Developing a Small Steam Plant
« Reply #11 on: September 15, 2019, 05:06:45 PM »
Looks nice  :)

Next up is the water reservoir. The body is cut from a bottle which was filled with Waitrose German Reisling which I had to get rid of before I could use the bottle  :wine1:.

Pleased to see you managed to cut the bottle on the first attempt. I am sure you would have hated to have to repeat the experience   :paranoia:

Jo
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Offline gary.a.ayres

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Re: Developing a Small Steam Plant
« Reply #12 on: September 15, 2019, 05:58:35 PM »
Thanks Jo.

Truth to tell, it is particularly brittle glass and I did break one. Or was it two? I can't remember...

And there were also the other ones that I bought in case of future breakages. My shop looks like the glass recycling depot at the moment...