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Bentwings

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I woke up at 2AM after falling asleep watching some mindless movie. However the great idea light bulb idea was on . Like most engineers I have the ever trusty note pad beside the bed just for these occasions. So I rolled over then realized I had not turned the coffee pot off. Sure enough the pot is burnt pitch black . I don’t think I can save it but I already have a new one in a box. But the idea hit me. I need an electrical heating element for an electric boiler. Well the coffee pot has a heater for heating the water it’s not quite boiling but about 180 deg. I think is the brewing temp for coffee. I do know it’s plenty hot , but it has another heater to keep the pot warm . It eventually will cook the water ou as it did. So, what about using these heaters to heat a boiler. The pot one is about 4” dis so I think a 4” cap might just fit it so there would be a near ready made set up. We are going over to the local metal supplier tomorrow. They cut to length anything you want and they have copper tubing in different wall thicknesses. So I’ll either pick up some material or will have it located easily they ship and deliver too. Then second idea. I m wondering how much torque these engines produce. Rpm is easy do a simple calculation can give BP but probably too small. However how do we measure it? Now the farm tractor thing is really primitive but does work . A simple fluid coupling using water would work. I could do a cad model then have it 3D printed or getting fancy have it 3D metal printed then it just smwounts and a scale . There are magnetic partial clutches too but they might be too expensive. PM models makes a high pressure hand water transfer pump that could be adapted. There is a way to calculate power or torque for this but I’ll have to look it up. They also have a boiler kit but I think it’s a fuel burner . I’m going to call and find out more about it.
I did some innovative negotiating yesterday , pat pat on back. Maybe I should run for office. LOL. MY CARE GELPER IS ALSO MY ACCOUNTANT AND KEEPS SPENDING IN LINE. Well with my eyesight and hearing difficulties I’ve had to give all of my hobbies. No cars, no machine shop , n baseball , no Rc airplanes . Basically just sit here untill it’s time for daily gated exercise walk. I said I needed something to do. Engineers don’t like sitting around. So I wentbintobwhatvthis hobby might be. It’s desk top. I have a nice desk and big computer and a few tools I can use at home . So she said that was a great idea. I didn’t say anything twice as above all didn’t whisper plus I stood for questions instead of exitig stage rear. More like Ted Cruz. Show real facts and present a good case. So a successful productive negotiation . So just like politics, increase the budget , decrease the bank balance.
So I can start having fun again .LOL
 

Bentwings

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I thought of that exactly I’m looking them now 1800 watts is still in the plug and play range . A heater like that gets a lot hotter a lot faster too . I have to measure my electric stove then I’ll see what is available as end caps. If necessary I can teach my son and grand son some metal spinning on our lathe . I still remember doing this in about 7th grade copper is easy and it sneaks easy then takes a nice finish.
Byron
 

SmithDoor

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Turn off the news and go to hobby shop build more models.
All politicians live on doom day.
It will repeat and repeat over and over.

Dave

I woke up at 2AM after falling asleep watching some mindless movie. However the great idea light bulb idea was on . Like most engineers I have the ever trusty note pad beside the bed just for these occasions. So I rolled over then realized I had not turned the coffee pot off. Sure enough the pot is burnt pitch black . I don’t think I can save it but I already have a new one in a box. But the idea hit me. I need an electrical heating element for an electric boiler. Well the coffee pot has a heater for heating the water it’s not quite boiling but about 180 deg. I think is the brewing temp for coffee. I do know it’s plenty hot , but it has another heater to keep the pot warm . It eventually will cook the water ou as it did. So, what about using these heaters to heat a boiler. The pot one is about 4” dis so I think a 4” cap might just fit it so there would be a near ready made set up. We are going over to the local metal supplier tomorrow. They cut to length anything you want and they have copper tubing in different wall thicknesses. So I’ll either pick up some material or will have it located easily they ship and deliver too. Then second idea. I m wondering how much torque these engines produce. Rpm is easy do a simple calculation can give BP but probably too small. However how do we measure it? Now the farm tractor thing is really primitive but does work . A simple fluid coupling using water would work. I could do a cad model then have it 3D printed or getting fancy have it 3D metal printed then it just smwounts and a scale . There are magnetic partial clutches too but they might be too expensive. PM models makes a high pressure hand water transfer pump that could be adapted. There is a way to calculate power or torque for this but I’ll have to look it up. They also have a boiler kit but I think it’s a fuel burner . I’m going to call and find out more about it.
I did some innovative negotiating yesterday , pat pat on back. Maybe I should run for office. LOL. MY CARE GELPER IS ALSO MY ACCOUNTANT AND KEEPS SPENDING IN LINE. Well with my eyesight and hearing difficulties I’ve had to give all of my hobbies. No cars, no machine shop , n baseball , no Rc airplanes . Basically just sit here untill it’s time for daily gated exercise walk. I said I needed something to do. Engineers don’t like sitting around. So I wentbintobwhatvthis hobby might be. It’s desk top. I have a nice desk and big computer and a few tools I can use at home . So she said that was a great idea. I didn’t say anything twice as above all didn’t whisper plus I stood for questions instead of exitig stage rear. More like Ted Cruz. Show real facts and present a good case. So a successful productive negotiation . So just like politics, increase the budget , decrease the bank balance.
So I can start having fun again .LOL
 

Bentwings

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Ok I’m in need of some boiler info. I’ve looked at some YouTube videos and they scarf me to death. I can’t believe some of the work published.
So I’ve studied se boiler tech already we need heat , need a tank end caps for horizontal boiler if it’s electric, need something for the unit to rest on he heater if using a stove top . Need air in with small blower. Now what are the stack of tubes for. I’m guessing additional surface area to heat the water . Then I assume the water Lee must be above the upper most layer ov these tubes , need a path for steam to the steam done where we tap into for supply line to engine engine exhaust can go into stack to help with circulation . Need various fitting bungs , whistle and safety valve. Stem on off valve for engine port for filling below height of water in boiler . Have to see where minimum level is and where max level is . Water pump needs to be able to it water in while steam is up . Temp gage , maybe low side and high side, pressure gage . What does the siphone line do?
Is there a start up proceedure for electric boilers Watlington makes Emmer’s ion heaters but I have not contacted them .
If I’m missing something feel free to educate me .

as I noted I can’t have a fuel boiler in the house so I’m stuck with electric PM has a kit but their sit doesn’t explain what what is in it.
byron
 

Richard Hed

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Ok I’m in need of some boiler info. I’ve looked at some YouTube videos and they scarf me to death. I can’t believe some of the work published.
So I’ve studied se boiler tech already we need heat , need a tank end caps for horizontal boiler if it’s electric, need something for the unit to rest on he heater if using a stove top . Need air in with small blower. Now what are the stack of tubes for. I’m guessing additional surface area to heat the water . Then I assume the water Lee must be above the upper most layer ov these tubes , need a path for steam to the steam done where we tap into for supply line to engine engine exhaust can go into stack to help with circulation . Need various fitting bungs , whistle and safety valve. Stem on off valve for engine port for filling below height of water in boiler . Have to see where minimum level is and where max level is . Water pump needs to be able to it water in while steam is up . Temp gage , maybe low side and high side, pressure gage . What does the siphone line do?
Is there a start up proceedure for electric boilers Watlington makes Emmer’s ion heaters but I have not contacted them .
If I’m missing something feel free to educate me .

as I noted I can’t have a fuel boiler in the house so I’m stuck with electric PM has a kit but their sit doesn’t explain what what is in it.
byron
My advice is to build a water tube boiler if you are designing your own. They are much safer than fire tubes. I thimpfks that people should only use firetubes for authenticitie's sake.
 

Bentwings

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Just checked on prices of copper tube and end caps. No wonder these little boilers cost so much . End caps go for up to $88 each for 4” ones . I don’t know if aluminum would hold pressure up to 100 psi after welding air tanks hold 125 psi all day . Might have go with thicker material . I could still spin form end caps I found a brazing rod for aluminum but that’s something I’ve not done I can weld or at least teach others to weld it so I suppose I could get 1/8” aluminum tube wall thickness and spin the end caps I hate to go with stainless as the heat transfer is terrible I could do steel too 4230 is available but a lot harder to spin form I could press for it but I don’t want to make die hydro forming could work but that’s no easy eithe in a small shop 4130 takes a lot of pressure I could do mild steel but then I have a half baked thing we’ll we are going to the metal supplier tomorrow so I’ll look around

Buron
 

Bentwings

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Well I did more checking around. I found an interesting aluminum alcohol fired boiler. However as I suspected, in the reviews a guy tipped over a lit alcohol burner and had a near blazing mess. However again I woke up at 2:00am and made a note on my note pad . My son has a number of aluminum automotive drive shafts. These are 3” round aluminum 1/4” wall . He said they take TIG welding beautifully. Not sure of alloy but probably 6061 as it weld very nicely . There are other alloys that weld even better but since these are already proven I got thinking an aluminum tube boiler might be nice these are not anodized so no special clean up required. I’m sketching a boiler now . It could have either welded ends or button head screws for more realistic look. Again my hot plate idea could work I think a bleed holes in the burner heating ring would help heat transfer . Teflon would make good end seals and the discs holding the pass through tubes could be Teflon too or aluminum . There are and number of bungs available too.
So that brings up gages I’ve just spent breakfast looking for small steam gages without much luck . Lots of automotive gages are available but they can take up a lot of room as most are 2- 1/16” diameter there are electric temp an pressure gages you can get pressure switches so it would be possible to have a low and high pressure cutoff . Getting really fancy and expensive there are digital and electronic gages. I had full compliment in my supercharged street rod. Probably more dollars in gages than even the highest price model steam engines. So I’m still looking for small gages . These drive shafts come in different diameters too . There is heavy wall small aluminum tubing available too. Prices are through the roof but not like copper. Plus the big stuff is already available. I may get out the cadd computer and see if I still remember how to run it . I found model generators to so
So I have some ideas here too.
Byron
 

Steamchick

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Hi Byron,
Putting it simply. As an Engineer... first calculate how much steam you want/need, then work out the size and configuration of boiler that suits you, then at 60% efficiency, work out how much electrical power you need. A guy at the local club thought a 2 kW kettle element could power an engine that needs 27 kW heat input from the coal fire...! I suggested he do some Engineering....
What engine do you want to run (bore, stroke, revs), what output power do you want from it (dynamo, water pump, etc.),
The cooker ring mentioned is 1800W. I use a 2.2 kW gas burner for a 3" vertical boiler for running a bicycle dynamo from an engine 1"bore and stroke. The bulb is 3W....!
K2
 

Bentwings

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Thanks for the tips. I have to turn another page in tech. Boilers are bad enough but now I’m adding output work capability. . Local car guy suggested using calculation for intake or carb. This is pretty easy it’s displacement then times rpm . I did this and I’m already probably ast th small air compressor capacity depending on operating pressure . Once steam gets past boiling point of water you get a huge increase in power output but then you have to add time at pressure. It’s getting complicated fast. I’m looking at partial brakes to provide torque reading thus hp or other units . I think it’s better to get the whole system up and running reliably before adding all the accessories . I dot know if the coffee pot heaters will provide enough heat. It will cost about $200 to build a prototype boiler out of what I have available I found a piece of aluminum plate that I could machine for close contact with a round boiler plus some polished as sheet for attaching cover . I tried to find gages but not having much luck . Automotive stuff is too big and messy for this unit. I’m going to get new laser temp gun in the morning so I’ll have plate temp and coffee pot boiler temps so I’ll be more able to see electric heat available . I did look at EV electric plate heaters and they would probably work as it’s still 110 vac and pretty low wattage out of the plug . Anyway keep the line open I’m having good time exercising the mind .

we are having a warm winter day so I can go for daily walk comfortably .
Byron
 

Steamchick

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Hi Byron, most books on model boilers spell out the steam demand calcs for engines. Volume of cylinder x rpm then steam tables to allow for pressure above atmospheric to determine energy required to boil water at that pressure... Simple enough for me, as the sums are like school at 14, not rocket science. But may sound daunting when you haven't done the calcs before.
I can dig out something in a few days, if you can't find it all on the web?
Also, for "Public liability", (ASME for boilers in the USA) the design of the boiler should be proven with all calculations showing a factor of safety greater than 8 times based on stress of boiler components versus 0.2% proof stress of the aluminium at the temperature of the boiler pressure.... and welds must be by a certified welder, with approved weld designs and materials. Many aluminium alloys are hardened and tempered for strength, but welded zones are annealed, which dramatically reduces the 0.2% proof stress, depending on the tempered state (if my memory serves..??).
So a lot of fairly simple sums to check your material sizes are good for your design before you cut metal.
Enough to keep your brain busy?
Wattage of the heater element should be stamped on the rating plate of your electric heater.
K2
 

Bentwings

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I did more thinking on this aluminum boiler I’m actually a certified Tig welder before all the vision issues but I’d hesitate to o a weld on boiler especially this thick on more or less unknown material . I can actually make an end cap that would have prong seal then use button head hex head cap screws to hold it in it would look locomotive like I’ve made many fuel tanks for racers and street rods. They all have held u nicely the boiler would be thick enough that all the fittings would have enough thread either in th steel or end caps so I think it would be ok I’m continuing design, maybe break out the solid works for final lay out . This little engine has 1.35 cubic inches. So at 1200 rpm it’s going to take 420 cam at what ever pressure needed. It sounds like a lot but others say these can be air hogs. The compressor I’m looking at is not quite big enough at 40 psi I don’t think . I suppose the more pressure the more power up to its limit. I think 1200 rpm is Lenny unless it is to run a turbine but that’s down the road. I think I opt for a neat coumound planetary drive at that point. I’m studying turbines now but that’s another planet for now we haven’t got to Mars yet. LOL
I REALLY APPRECIATE THE COMMENTS. Don’t be afraid to challenge me. I won’t walk off the stage or whisper .LOL
 

Richard Hed

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I did more thinking on this aluminum boiler I’m actually a certified Tig welder before all the vision issues but I’d hesitate to o a weld on boiler especially this thick on more or less unknown material . I can actually make an end cap that would have prong seal then use button head hex head cap screws to hold it in it would look locomotive like I’ve made many fuel tanks for racers and street rods. They all have held u nicely the boiler would be thick enough that all the fittings would have enough thread either in th steel or end caps so I think it would be ok I’m continuing design, maybe break out the solid works for final lay out . This little engine has 1.35 cubic inches. So at 1200 rpm it’s going to take 420 cam at what ever pressure needed. It sounds like a lot but others say these can be air hogs. The compressor I’m looking at is not quite big enough at 40 psi I don’t think . I suppose the more pressure the more power up to its limit. I think 1200 rpm is Lenny unless it is to run a turbine but that’s down the road. I think I opt for a neat coumound planetary drive at that point. I’m studying turbines now but that’s another planet for now we haven’t got to Mars yet. LOL
I REALLY APPRECIATE THE COMMENTS. Don’t be afraid to challenge me. I won’t walk off the stage or whisper .LOL
I still opt for water tube design.
 

Bentwings

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I still opt for water tube design.
Yes I’m planning on tubes I haven’t worked out how many I could mount them in a Teflon disk or even aluminum . I thought about locking the assembly in place with button heads but I think it best not to have holes that might not seal up easily end caps can be sealed pretty easily but a bulk head leads to expansion due to heat so I think I can just use a spacer ring between the bulk heads and end caps that way the tubes can sort of float as temp changes. My son has a tool that can dent or make internal bulges but I don’t know how big or small it goes.
Well it’s bed time here kitty just jumped in my lap so she is reminding me. .

byron
 
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Richard Hed

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Yes I’m planning on tubes I haven’t worked out how many I could mount them in a Teflon disk or even aluminum . I thought about locking the assembly in place with button heads but I think it best not to have holes that might not seal up easily end caps can be sealed pretty easily but a bulk head leads to expansion due to heat so I think I can just use a spacer ring between the bulk heads and end caps that way the tubes can sort of float as temp changes. My son has a tool that can dent or make internal bulges but I don’t know how big or small it goes.
Well it’s bed time here kitty just jumped in my lap so she is reminding me. .

byron
Could you draw a sketch and post it?
 

Balta

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A while ago I remember seeing an article somewhere in which this guy made an aluminum melting furnace out of a stove heating element. At the right temperature they can be reshaped to comply to your space needs.
 

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Hi Balta: I tried using a 2.5kW grill element in a muffle furnace to anneal some hard steel... but it easily burnt-out before I got near to "aluminium " melting temperature... I understand the elements can only take 400~450 deg. C, or so, for external temperature, as they are essentially "close to their limit" in a cooker, so they can glow red as grill elements, and rely on the fresh air in the grill to keep them from fusing. Increase the fresh air by a couple of hundred deg. C. and the elements rise in temp by enough that they fuse... You may be able to get away with something if it was designed to glow red-hot, if you turn down the input power (voltage) to prevent it glowing hotter than it was designed to run at. a cooker simmerstat didn't do that for me, as it essentially switches ON and OFF full voltage. But a voltage controller - connected to an infra-red thermometer for temp feedback could possibly do it. BUT: The muffle furnace - for all the firebrick insulation - still warmed the garage better than a 3 kw heater, with external losses. So a furnace to melt a pot of aluminium should need at least 4~6kW, I reckon, if you have 4" thick firebrick insulation. - Look up specs of commercial hobby foundry furnaces on £&@y, or wherever.
K2
 

Steamchick

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Hi Byron, your post #31... "thinking on this aluminum boiler I’m actually a certified Tig welder before all the vision issues but I’d hesitate to o a weld on boiler especially this thick on more or less unknown material." - YOU know better than I what welding entails as a certified welder. So if you know a mate who is certified (as a Welder in aluminium for pressure vessels), maybe he can do the work for you. Sorry to hear of your poor sight, I have heard this one all to often on these threads. Must be very frustrating!
(My friend is now down to his last 15% of sight in the "working" eye. Just sees grey shadows.).
I did a quick calculation - based on ASME and a bit of guesswork...
A 3" aluminium pipe - 1/8" thick - with penetrations (MUST be bushed) should only take max. steam pressure of 60psi. (This gives a Factor of safety of ~8.5, and ASME require >8). I have considered the inclusion of side penetrations to the boiler (for water level gauge, etc).
BUT I have not considered the weakening of aluminium for temperature.
- Extrapolating from some website material, I can estimate the further drop of Max pressure "for ASME" would be about 75% = MAX. 45psi - with a FOS of 8.1. (So maybe 40psi is a better NWP value!).
But as these are based on unknowns of material grade, what penetrations you'll use, and exact material degradation by welding and at elevated temperature, then there is a margin of error of my calculations, so do not quote me!
However, this is an indication that if you want a welded aluminium boiler then the "unknown material" is only good for 45psi MAXIMUM.
Maybe you want to think again, and consider not using unknown "scrap" material for something with as much stored energy as a hand grenade, that would release scalding hot STEAM if it failed explosively. (Even a crack would release a jet of invisible steam, before cooling and becoming a visible cloud of water vapour).
Please remember, if properly Engineered, and Manufactured, with known materials and processes, these things are safe. But if you do either the Engineering or the Manufacture badly, or use inferior materials or processes, you have a BOMB. (Not a can of worms, but a can of stored energy that can instantly and violently be released).
Food for thought? Sleep well.
K2
 

Steamchick

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Hi Byron,
Your compressor sounds like a better option if you are indoors and cannot have a gas-fired boiler.
You say "This little engine has 1.35 cubic inches. So at 1200 rpm it’s going to take 420 cam at what ever pressure needed. It sounds like a lot but others say these can be air hogs. The compressor I’m looking at is not quite big enough at 40 psi I don’t think . I suppose the more pressure the more power up to its limit. "
To answer step by step:
  1. Assuming this is a double-acting single cylinder engine: You have 2 x 1.35cu.in. per rev. I reckon max you will run at is 2000rpm... (trust me, a good engine will do that!). So you want 162cu.in.per min - AT PRESSURE. So if you think of maybe 60psi (to drive a generator or something?) = 4 bar = you'll need a compressor for 0.4CFM. - or if at 100psi, = 0.625CFM... Tiny by compressor standards, I have one in my garage (for tyre inflation, and running-in engines!) at 2CFM.
  2. K2
 

Balta

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There you go Steamchick, first hand experience beats heresy every time.
 
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