Stuart Triple new build

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On the quistions if there is somone how had the Stewart Triple running on steam I can show you the Triple made by John Viggers, it is the Triple of the castingset by E&JWinter in Sydney and by the drawings of OB Bolton witch are revised by J.P.Bertinat. It is a simmiler version of the Stewart one only a little bigger and with a inclosed condensor. John Viggers has build this one and made a blog about the building of it on https://johnsmachines.com/category/triple-expansion-miniature-steam-engine/ there he showing the Triple running on steam.
 
Hi John, Thanks, a great blog site you have. I just cou;dn't figure how to post comments - that you need to support the site.
But here are some tips of what I do - which may or may not suit what you are doing. You take what you need and discard the rest!
First, Lagging.
I reckon you can lose of the order of 5psi of steam pressure by not lagging your steam pipes. Polished copper makes things "pretty", but if we are showing off "Engineering" then we should be managing heat better. I lag my steam pipes (NOT the syphon tube, or cold pipes) by winding cotton string around the pipes. It takes time and care, but you modelling shows you understand that. When finished, the cotton is painted with white emulsion paint. It then looks a lot more like a "Proper" engine room set-up, and has the advantage that the boiler needs a few psi less pressure to run engines about the same speed. You can lag the manifold (Steam fountain) as well if you desire, as otherwise you are simply condensing steam before it feeds down the main pipe.
Next: The fire:
I worked where calculations of radiant heat were daily considerations. Inside your boiler you have a nice flame fire from the burner. But you can improve the heat transfer CONSIDERABLY by adding a radiant element inside the firebox. I.E. LOOSELY compressed wire wool - I use stainless steel pan scourers as they are cheap and good stainless steel wire. I have also used electric element wire from old electric heaters that simply have resistance wire that glows red hot.... It lasts forever, almost! Once you have seen where the fire heats some wire wool red hot, you can even have fun making a shaped wire wool element to just fit in that part of the flames. What this does is take hot flame energy and broadcast it to the walls of the firebox, and into the water for boiling and steam. Then the flue gases are a bit cooler, and less dense, so the flue can take more exhaust... = a bigger fire! There will still be plenty of hot gas up the flue to the chimney stack. Ideally, the bottom of the chimney is only 20degrees or so above steam temperature, for an efficient boiler. I assume (Which makes an "ass of me") that you are superheating the steam, as all you want the steam to do is carry heat through the engine, not condense until you reach the condenser... even though some will as it expands and cools.
Boiler lagging. Underneath the gorgeous wood lagging and brass banding, I guess you have some conduction barrier - matting - or something? As a check, how hot is the outside of the boiler? I can comfortably just warm my hands by wrapping them around the lagging, no risk of burning the flesh, as I have "good" insulation. I use an aluminium foil sheet glued onto the copper boiler. Wrapped in a mat of conductive insulation. (I have used proprietary stuff, also COTTON flannel, a piece of an old WOOL garment, corrugated cardboard. Then another sheet of aluminium foil, covered in a nice vanished wood cladding, or aluminium casing, or whatever. The 2 layers of foil separated by conductive insulation, form a radiant insulator, that stops more heat escaping than the wood cladding can. I demonstrated this recently, when firing an horizontal boiler, where a part of the boiler was yet to have cladding fitted. The clad part was at over 100deg.C. the unclad part 135 deg C as was the steam inside the boiler. Until I covered it with 2 layers of foil, a bit crinkly so there was a small air gap, when the thermometer showed only 30 deg.C on the outside! Made a big difference to the quantity of steam produced as well! Colleagues were amazed!
Superheating. The aforementioned boiler I was firing had about 8 inches of a single (1/4in bore pipe) tube in the fire (Very hot!), but a colleague has done calculations, and it really needs up to 5 times that to have a "proper" rise of steam temperature (not pressure) in the outlet pipe, when in flue gases, not the fire. I have a 3 in boiler, with a steam pipe fed through the fire, with nearly 2 ft of tube in the fire (coiled). Suggestions are for the superheater to have up to 80 times the bore diameter of length when in hot flue gases, post-boiler. In a triple expansion engine, you'll run a lower steam pressure with more superheat.
The engine. I see it has auto-drian valves on top for prevention of hydraulic locking when worming from cold. I guess also steam (condensate) drains on the bottom cylinder covers? Otherwise the hydraulic lock when running-up from cold will blow the con-rod glands, whatever they are made from. I find on a twin expansion engine, that the drains open, I can hand crank the engine for 5 mins or so before the condensate is almost down to a drip or 3..., when it will just start running with drains open. Then when I close the drains on the HP stage, the LP stage takes a further 5 mins or more to warm-up. Even after closing the drains on the LP cylinder I run at about 12-15 psi before the LP starts to work, when the revs rise noticeably! I can then drop the steam to around 10 psi when the engine will idle about a similar speed to your show demonstration. I guess you find something similar as your engine warms-up? Considering it is really just a single cylinder engine when staring from cold, (Insufficient hot steam to IP and LP for then to do any work) I think you lack of self-starting in one video is simply a cold engine? - But you are right in that a difference between forward and reverse speeds at the same steam regulator setting is indicative of a valve timing glitch. (Assuming you have low friction in the cross-head slide when running in both directions).
Finally, I like the gauge glasses with a built-in red line - make the water level very clear - or use a card behind with 45 degree lines. They reverse direction at a certain optical distance from the glass where the glass is full of water.
I hope some of these ideas are useful?
I do wish I had the patience and skill to make such good looking models as yours! What I make is truly crude by comparison!
K2
 
Hi Steamchick
Thanks for your comments they are all good ideas. I am battling health issues at present and hope to get back to making models soon.I have noticed in your comments from other threads that you can design ceramic burners, I would like to try one in my boiler but do not understand them enough to start one. What information do I need to start.
Cheers
emers
I can be reached at
[email protected]
 
Hi Emers,
This week I made a burner:
20240613_175418.jpg
- rated about 2.7kW - but it may manage a larger jet? (Designed for a 3.4kW gas jet - I need to make one and try!).
Needs a bit if tidying-up. (My painting is tatty, Silicon sealant leaked on one edge, etc.). It is for a "Stuart" style horizontal boiler, 3 in dia x 8 in long, with some water-tubes beneath.
It shows what can be done.
But there are other (better?) designs as well as ceramic burners.
See some commercial brochure information attached. This is one design. (4 in diameter). A few times more heat than a 4in dia ceramic....
35328823463_6006abec27_2.jpg
My talents at making the wire mesh burners is yet to be realised... as can be seen here!
P6262365.JPG

P8162336.JPG

K2
 

Attachments

  • Bekeart Brochure_Premix gas burner_A4_EN_LR pages.pdf
    578.8 KB
  • REZNOR Infra-red heating tech info.pdf
    462.1 KB
And a "4in" diameter ceramic I made...
P4282467.JPG

I think this was rated around 2.4kW. Designed for Butane, I needed to mask some air holes when used with Propane. This sold on Ebay for around £25 + P & P.
K2
 
I thought you may like to see the solid crank i have started to make with internal eccentrics for the triple compound
 
Wow! 😯
I heard your disappointment in your voice.
BUT Looking forward to seeing the successful conclusion in due course.
Thanks for posting that one...... A REALLY interesting machining process. It seemed much more stable and precise than simply turning an eccentrically held bar to achieve cranks and eccentrics. But I should have liked to see the crank webs held separate by a precision spacer/jack, to avoid the end pressure on the bar from bending each crank-pin (however so slightly).
THANKS!
K2😯
 
It will be published on Thursday the second one... the Myford would have been destroyed if I had turned it from scratch (I did try) but the result was a success. The end pressure on the cranks are a problem down the road.
Thanks for the comments...watch this space.

Andy
 
Looking at your bar, I wondered if across the "made" cranks, you could silver solder a sleeve - which is removed after all the cranks are made? - The sleeves can take the end thrust from the centre while machining the next crank pin. - Possibly loctite will do? - then after baking at "breakdown temperature" the sleeves can be knocked off, with less temperature used than for silver soldering?
K2
 
Hi John, Thanks, a great blog site you have. I just cou;dn't figure how to post comments - that you need to support the site.
But here are some tips of what I do - which may or may not suit what you are doing. You take what you need and discard the rest!
First, Lagging.
I reckon you can lose of the order of 5psi of steam pressure by not lagging your steam pipes. Polished copper makes things "pretty", but if we are showing off "Engineering" then we should be managing heat better. I lag my steam pipes (NOT the syphon tube, or cold pipes) by winding cotton string around the pipes. It takes time and care, but you modelling shows you understand that. When finished, the cotton is painted with white emulsion paint. It then looks a lot more like a "Proper" engine room set-up, and has the advantage that the boiler needs a few psi less pressure to run engines about the same speed. You can lag the manifold (Steam fountain) as well if you desire, as otherwise you are simply condensing steam before it feeds down the main pipe.
Next: The fire:
I worked where calculations of radiant heat were daily considerations. Inside your boiler you have a nice flame fire from the burner. But you can improve the heat transfer CONSIDERABLY by adding a radiant element inside the firebox. I.E. LOOSELY compressed wire wool - I use stainless steel pan scourers as they are cheap and good stainless steel wire. I have also used electric element wire from old electric heaters that simply have resistance wire that glows red hot.... It lasts forever, almost! Once you have seen where the fire heats some wire wool red hot, you can even have fun making a shaped wire wool element to just fit in that part of the flames. What this does is take hot flame energy and broadcast it to the walls of the firebox, and into the water for boiling and steam. Then the flue gases are a bit cooler, and less dense, so the flue can take more exhaust... = a bigger fire! There will still be plenty of hot gas up the flue to the chimney stack. Ideally, the bottom of the chimney is only 20degrees or so above steam temperature, for an efficient boiler. I assume (Which makes an "ass of me") that you are superheating the steam, as all you want the steam to do is carry heat through the engine, not condense until you reach the condenser... even though some will as it expands and cools.
Boiler lagging. Underneath the gorgeous wood lagging and brass banding, I guess you have some conduction barrier - matting - or something? As a check, how hot is the outside of the boiler? I can comfortably just warm my hands by wrapping them around the lagging, no risk of burning the flesh, as I have "good" insulation. I use an aluminium foil sheet glued onto the copper boiler. Wrapped in a mat of conductive insulation. (I have used proprietary stuff, also COTTON flannel, a piece of an old WOOL garment, corrugated cardboard. Then another sheet of aluminium foil, covered in a nice vanished wood cladding, or aluminium casing, or whatever. The 2 layers of foil separated by conductive insulation, form a radiant insulator, that stops more heat escaping than the wood cladding can. I demonstrated this recently, when firing an horizontal boiler, where a part of the boiler was yet to have cladding fitted. The clad part was at over 100deg.C. the unclad part 135 deg C as was the steam inside the boiler. Until I covered it with 2 layers of foil, a bit crinkly so there was a small air gap, when the thermometer showed only 30 deg.C on the outside! Made a big difference to the quantity of steam produced as well! Colleagues were amazed!
Superheating. The aforementioned boiler I was firing had about 8 inches of a single (1/4in bore pipe) tube in the fire (Very hot!), but a colleague has done calculations, and it really needs up to 5 times that to have a "proper" rise of steam temperature (not pressure) in the outlet pipe, when in flue gases, not the fire. I have a 3 in boiler, with a steam pipe fed through the fire, with nearly 2 ft of tube in the fire (coiled). Suggestions are for the superheater to have up to 80 times the bore diameter of length when in hot flue gases, post-boiler. In a triple expansion engine, you'll run a lower steam pressure with more superheat.
The engine. I see it has auto-drian valves on top for prevention of hydraulic locking when worming from cold. I guess also steam (condensate) drains on the bottom cylinder covers? Otherwise the hydraulic lock when running-up from cold will blow the con-rod glands, whatever they are made from. I find on a twin expansion engine, that the drains open, I can hand crank the engine for 5 mins or so before the condensate is almost down to a drip or 3..., when it will just start running with drains open. Then when I close the drains on the HP stage, the LP stage takes a further 5 mins or more to warm-up. Even after closing the drains on the LP cylinder I run at about 12-15 psi before the LP starts to work, when the revs rise noticeably! I can then drop the steam to around 10 psi when the engine will idle about a similar speed to your show demonstration. I guess you find something similar as your engine warms-up? Considering it is really just a single cylinder engine when staring from cold, (Insufficient hot steam to IP and LP for then to do any work) I think you lack of self-starting in one video is simply a cold engine? - But you are right in that a difference between forward and reverse speeds at the same steam regulator setting is indicative of a valve timing glitch. (Assuming you have low friction in the cross-head slide when running in both directions).
Finally, I like the gauge glasses with a built-in red line - make the water level very clear - or use a card behind with 45 degree lines. They reverse direction at a certain optical distance from the glass where the glass is full of water.
I hope some of these ideas are useful?
I do wish I had the patience and skill to make such good looking models as yours! What I make is truly crude by comparison!
K2
I hate Mylar !!! but makes the bet reflective barrier
 
Hi T.S. My concern for using Mylar as the reflective heat barrier on a boiler would simply be temperature. A boiler at 100psi is around 338F, or 170 deg. C.
Mylar with aluminium is probably OK for an outer layer of insulation, but NOT against the boiler/steam parts.
To quote the manufacturers:
The versatile properties of Mylar, and its ability to retain its properties across a wide temperature range (-94°F to 302°F or -70°C to 150°C), make it ideal for a variety of applications across different industries.
So use pure and simple aluminium foil against the boiler to reduce the emissivity of the Hottest surfaces. - Try to make it look like a vacuum flask! - THEN cover with a non-heat conducting material (Corrugated cardboard is ideal wrapping for a boiler shell!). THEN it should be cool enough for aluminium coated reflective Mylar, but I use more aluminium foil. Outside of that the cosmetic cover (painted steel, varnished wood, etc.) looks good and adds a little..
K2
 
Remembering my Grandfather's ship (and from what I have read)...
The Titanic's triple expansion engines ran on steam - not compressed air - so Enthalpy was different.... - and there were 2 main engines feeding the single turbine. This simulation will be handicapped by half the steam missing, sorry all the missing steam, and only having a whiff of air to drive it. I would "hide" a secondary pipe of "full" air flow and pressure to the turbine to really show what it was doing. I should also add an oiler - taking compressed-air tool lubricant - to the feed to the main engine... but that is just detail. Also, an oil tank with some fine lubrication pipes to drip feed the cross-head slides, crank bearings, etc, and other externals that need oil? - Then a boiler, feed-pump, etc. to provide steam, when a condenser can also be fitted... and condensate returned to the boiler... then a hull - Titanic, Olympic, or Britannic will do?
https://en.wikipedia.org/wiki/White_Star_Line
A modeller's work is never really finished...
But lovely modelling! - And it runs, smoothly, without doing anything dramatic at full speed.
WELL DONE SIR!
K2
 
shall I post it to you to finish hahahaha ...many thanks I will be running it on Steam soon...
 
Hi Anday1.. I am afraid it would be a long way down the list of jobs I have on the bench....
  • A 3 1/2in Tich - belongs to my club - recently inherited from a recently passed member. ("passed-away", as well as "past"). Out of respect for his fine workmanship, I am in the process of servicing it prior to getting it re-certified and running again.
  • 3 of my boilers - needed some mods, and re-certification, as the COVID lapse of certification means they are now considered "New" and needed bringing to today's standards for calculations to be acceptable.
  • A new gas burner for a Club boiler, to increase the power available - due for the next Annual re-test. (A new steam test required when I finish installing the burner).
  • A steam pump - Half-built but not touched for a year due to other jobs jumping ahead in the queue,
  • A small Mamod bench boiler - with feed-pump, etc. making it a "proper" set-up for continuous running, not just the toy "fill and run till empty" strategy. I want to run a 1in bore and stroke DA engine at up to 15psi with my "improved" heating strategy. POSSIBLY it can run your triple expansion engine (at no load)? - not just a little Mamod oscillator.
  • An improved superheater for the Club's "Stuart" boiler, that was recently brought back into service and has a more powerful gas burner to run a Tesla Turbine. The original burner was about 0.8kW (Gas power) - replacement ~3kW... Stuart certification of 60psi was not available for traceability so the Inspector insisted I do calculations - that meant adding stays so it can be certified at 30psi. (As a "new boiler" - for 2018 regs!).
  • And 2 steam boats, another stationary boiler, etc. all need servicing and new certification... and I must make 2 hand feed-pumps, valves, fittings etc.
  • And a Super-Simplex boiler needing a repair and re-certification... and maybe a gas burner?
  • Then I can get back to planning how to combine a boiler with a Stuart SUN engine and generator I made previously...? ...etc.
More than enough for the present!
I'm sure this is the norm?

I am looking forward to your next project!

K2
 
You have enough to do...just live another 100 years which I hope you do and you will be finished lol
 
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