I built a steam powered tricycle but have been having problems going any distance with it. It has a combination firetube - watertube boiler and when fired hard the water bubbles up and goes out the outlet, locking up the engine. I am building a trap consisting of a brass vessel about 1-1/4" dia and
3-1/2" long. I plan to put insulation on so as not to lose too much heat. I'm trying to decide what would be the best material for this. It should be inexpensive, fireproof and easy to apply. Any ideas? Engineman
Search for the likes of Kaowool which is a ceramic fiber blanket. It comes in various densities and insulation values, denser seems better insulating IIRC. IIRC Kaowool is not good to breath the fibres of in any quantity but there is a similar product which is body soluble but doesn't have the same upper working temp, mind you the body soluble stuff goes to about 1200C so most likely fine for your app . A good place to start would be a ceramics/potters supply or a general refractory supplier. I know about it through my involvement in glass blowing.
Pipe insulation, for example this stuff from McMaster, which is good to 850F. Remove the outer covering if the outside will be exposed to high temps. I'm sure you can also find it locally.
5556K33 High Temp Fiberglass Insulation for Pipe 1" Thick, 1-3/8" Inside Diameter, 3' Length In stock at $8.07 Each
I'd give ideas from my "never done it myself" perspective, but the photos are too small and too far away to see exactly what you did.
Do you have a real "Steam Dome" on the boiler, or a superheater coil? (You only mentioned a feed-water preheat coil.) The steam dome tries to get some vertical distance from the water level so it doesn't work water, and the superheater coil would heat up and flash any water that got that far.
The dome is supposed to tap from the center, so surging water from acceleration or braking or turns or hills stays out of the dome - if you are tapping the main steam outlet from the side of the boiler like a standard VFT design (and it sure looks like that on the 'engineassembled' page) I'd expect bad working water every single time you made a left turn.
Try putting an upside down U loop on the main steam line to the engine, large enough to keep the velocity down and allow the water to separate and drain back, and insulate the heck out of it - that might be enough.
Next step - build a water tank sitting in back next to the propane.
Now you've got me thinking of building one... But where the heck can you get a small steam turbine alternator (12VDC 30A-50A) to run all the accessory loads? The ones from locomotives are a bit big.
Bruce, you seem to have a quite a bit of know-how in a lot of different subjects, not only electricity but autos and even steam engines. I don't know if you are serious about building a turbine driven alternator but here is an idea about using an old turbocharger for a steam turbine.
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I have another question for you or the group: I have had problems with the heat from the lower boiler housing causing tire blowouts. The housing gets red hot in places and is inly about 1/2" from the tire. there is no way that I know of to fasten insulsation to this surface that will stand the temperature and rough handeling so I'm making a heat shield. I'm using a piece of 20 ga. stainless and tack welding it to the boiler housing. I picked stainless for it's poor heat conductivity and I'm polishing the inside surface to reflect radiated heat. My question is whether it would help to polish the metal on the tire side also? Engineman
photos are too small and too far away to see exactly what you did.
Do you have a real "Steam Dome" on the boiler, or a superheater coil? (You only mentioned a feed-water preheat coil.) The steam dome tries to get some vertical distance from the water level so it doesn't work water, and the superheater coil would heat up and flash any water that got that far.
The dome is supposed to tap from the center, so surging water from acceleration or braking or turns or hills stays out of the dome - if you are tapping the main steam outlet from the side of the boiler like a standard VFT design (and it sure looks like that on the 'engineassembled' page) I'd expect bad working water every single time you made a left turn.
Try putting an upside down U loop on the main steam line to the engine, large enough to keep the velocity down and allow the water to separate and drain back, and insulate the heck out of it - that might be enough.
Next step - build a water tank sitting in back next to the propane.
Now you've got me thinking of building one... But where the heck can you get a small steam turbine alternator (12VDC 30A-50A) to run all the accessory loads? The ones from locomotives are a bit big.
:I have had problems with the heat from the lower boiler housing causing tire blowouts. The housing gets red hot in places and is inly about 1/2" from the tire."
ceramic coating I was going to suggest aluminum but at that distance and temperature you are dealing with more than just infrared, crossing into visible and uv. Microwaves?
If I can line up all the pieces, then I might think about actually building a steam launch - I can get a good used fiberglass dory or catamaran style hull and a lot of the necessary marine hardware for practically free. But I hate getting started on something I know can't be finished, because either the parts don't exist, they're too expensive to buy pre-made, and/or it'd cost too damn much to invent them from scratch.
I've found scale turbogenerators for 1.4" - 1' Live Steam Railroad engines on teh intarwebs, but they're 6V 0.5A which isn't enough for me - But it would be perfect for a bicycle headlight and taillight. (Though for $500 you could buy a whole lot of D batteries...) For a steam launch you need to run the oil burner, navigation and cabin lights, bilge pump and other auxiliaries you need roughly 12V
30A to charge the batteries.
A plain old car alternator would be perfect, now you need a constant
2000 to 4000 RPM power source to drive it - too fast for a piston auxiliary engine unless you use a step-up geartrain, and adding complexity is bad. And running an alternator off the prop shaft is iffy, because the main engine stops - though having two alternators (like two feedwater pumps) would be perfect.
I'll go look, but turbocharger turbines are built for a LOT more flow and 50K - 80K shaft RPM, much higher than an alternator needs. The perfect thing would be a turbine section (and the speed regulation gear) from an old Pyle National railroad turbogenerator, toss the generator section and couple up a Delcotron.
As to figuring it out, it's all simple machines when you strip off the falderol. And I have friends who work with them on a regular basis, so you pick up on the nuances.
A Vertical Firetube Boiler is more designed for marine uses, and you don't toss them around that much. The usual placement of the steam taps on the top edge of the drum will pick up water if you toss the boiler around violently, unless they put internal baffles around the boiler outlet fittings to prevent it - just like the sectioning baffles in a tank truck keep the cargo from all rushing to the front.
The whole reason for a steam dome on a horizontal locomotive boiler was that they DO accelerate and brake hard, go up and down hills, make turns at speed, etc. Putting the steam dome and throttle valve in the center highest point was to keep from working water if at all possible.
They also have this little problem with the crownsheet being exposed and overheated going down hills, but we don't need to go into what happens after that...
Myself, I'd redesign the boiler mounting bracket out a little farther to gain another inch or so between the boiler shell and the front tire, you need a little more space to work with. Then make your heat shield.
And if a simple heat shield won't do it, make a sandwich heat shield
- two sheets of metal riveted at the edges with 1/2" of Kaowool or other high temperature refractory insulation in the middle. And go all the way down the side of the boiler to stop all the radiant heat on that side.
The heat shield can't be in direct contact with the boiler shell, or it will conduct the heat. You need to mount it off on brackets or tabs, to break the conductive path. Go look at the heat shields on a catalytic converter.
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