Medium sized monotube boiler

[ksouers]

Ranger,
You're quite welcome. I'll help any way I can, I'm sure everyone else will too. We would like to see your project be successful. But also very safe.

The spark plug hole can be a drain, but you'll have to put a valve on it so you can close it off.
Are you still using the old Briggs oiling system? A splasher or a pump on the cam?
If you aren't, you could run the engine upside down. If you are, then make a removable crank handle for the driveshaft. After you shutdown the engine, AND DISCONNECT THE STEAM LINES, open the drain and crank it over by hand a few times. This will displace any steam left in the cylinder. Leave the valve open so any moisture can evaporate.

Firebox:
I can think of a few fuels you might want to use. Each has advantages and disadvantages, naturally. I'll spell them out as I see them, you get to decide.

Wood: pro:cheap, abundant con:may be hard to start. Hard to control. Burns irregularly.
Charcoal: pro:abundant, reasonably priced, easy to light con:hard to control. Burns irregularly.
Alcohol: pro:abundant, easy to light, easy to control con:very expensive, half the energy of gasoline.
Gasoline: pro: significant energy, easy to light, easy to control con: highly flammable, very dangerous, expensive.
Diesel fuel: pro: more energy than gasoline, easy to light, easy to control con:expensive, dangerous.

First thing, toss out gasoline. That's a non-starter. Way too dangerous.

Alcohol seems like a good choice, but it is very expensive. You will need a significant amount and it is more expensive than gasoline.

Wood and charcoal are good choices. They burn slow, but hot. Lots of energy there. And the price isn't bad. But the fire can be difficult to control, it flares up and burns down to just coals. Still, a good choice. You will need a quick way to extinguish the fire.

Diesel fuel could also be a good choice with a proper burner and flow control. It is expensive though, more so than gasoline. It burns fairly slow for a liquid, but hot. Lots of energy, significantly more than gas. Kerosene could be substituted.

Do some reading, learn how a fire works. What three things does a fire need to sustain itself?
How does fuel actually burn?



Before you start building you need to think about a couple things. How are you going to operate your boiler? How are you going to start it? What steps do you take, in what sequence?
What is the maximum length of time you will operate the boiler?
How will you shut it down? What are the steps? How are you going to test your boiler?
How will you identify a pending emergency? What will you do to prevent it becoming an emergency?
What will you do in the event of an emergency? What kind of emergencies are possible? Not just best-case scenarios, what is the worst that can happen?
Believe it or not, most accidents can be avoided through very simple measures. It's just that too often people don't think about them.

If you are going to operate your boiler in a safe and professional manner, you will need to know these things.

Above all, ask questions.

 

[tel]

I really appreciate your help Kevin. Will the spark plug hole act as a drain? Since its a vertical engine I dont think water will drip out. I may want to go with a single uniflow exhaust hole, it will not be for exhust but simply drain water.

Ok, now I just have about everything covered on the boiler, now for fire. I want to run on a gravity fed oil system, but any other suggestions will help. No Propane.

The idea is not for the condensate to drip out, but to be expelled by the rising piston/expanding steam - hence the need for a ****. When starting up you open the **** until the engine heats up, blowing the condensate out, if your steam is particularly wet you may also have to crack the **** periodicaly during the run.

Here's one of my engines, a single acting double, fitted with automatic drain cocks - note that they are as high up on the cylinders as I could get them.

 

[rangerssteamtoys]

Before you start building you need to think about a couple things. How are you going to operate your boiler? How are you going to start it? What steps do you take, in what sequence?
What is the maximum length of time you will operate the boiler?
How will you shut it down? What are the steps? How are you going to test your boiler?
How will you identify a pending emergency? What will you do to prevent it becoming an emergency?
What will you do in the event of an emergency? What kind of emergencies are possible? Not just best-case scenarios, what is the worst that can happen?
Believe it or not, most accidents can be avoided through very simple measures. It's just that too often people don't think about them.

If you are going to operate your boiler in a safe and professional manner, you will need to know these things.

Above all, ask questions.

Believe me, I have sit in a chair having so much fun going over the process of running the engine ;D Thats where being a kid helps, you can pretend without looking like an ***** :bow:
I can answer most of the questions, except the what to do in the event of an emergency, I cant plan ahead like that. If I dont plan ahead, I usually do pretty good in an emergency :-\
As for the burner I'm probably going with a forced air oil burner, the firebox will need a bit of refractory to withstand the heat. Look at this http://www.backyardmetalcasting.com/oilburners08.html Pages 8-9 is what I'm thinking. I cant get it to go vertical so like I said refractory will be needed or some insulation to prevent melting the firebox.

Now back on the water pump, I well my dad gave me the idea of using a new grease gun. It can give good pressure, pump quite a bit of water, has built in check valves (I think, and hope) and is easy to get, also CHEAP

As for the drain cocks, thats a good idea. Use steam to blow out any water at first. I will have to make a mark on the pulley to do that so I can get it between TDC and BDC on the intake stroke. Open the drain and warm up the cylinder that way, since the gas engine is designed to get rid of heat; I will have to insulate the cylinder. Work on that tomorrow.
Cost of this project so far, $0.00 I want to get costs to a minimum.

 

[ksouers]

I can answer most of the questions, except the what to do in the event of an emergency, I cant plan ahead like that. If I dont plan ahead, I usually do pretty good in an emergency :-\

First:
You can.
And you must.

If you don't plan ahead, if you just plunge in head first without preparation you WILL have a disaster!

Read what I wrote again. Look at it from a different point of view. Those things are to PREVENT an emergency situation. You need to know those things so that you can catch problems BEFORE they get out of hand.

Possible scenario:
The tube ruptured and sprayed hot, burning oil all over the yard. No one is hurt but the grass is on fire and the wind is blowing the fire towards the garage.

You didn't plan ahead:
Where's the fire extinguisher? In the garage? In the kitchen? Where is the water hose? The front yard? While you're running around, the garage catches fire.

You DID plan ahead:
The water hose and fire extinguisher are right there with you. You grab the hose and start dousing the leading edge of the fire. Disaster averted by simple, easy preparation and forethought. Yeah, the grass got scorched. It'll grow back. But the garage, Corvette and Chevy are safe. So is Ranger.

 

[rangerssteamtoys]

Well for me, all those things are second nature. I did another firing of the boiler today, again just the outer shell. Water hose was about 3 feet away from me if anything went wrong. Like say the prototype oil burner I was testing, blew up sending hot oil lighting the grass on fire. The water hose is right there, if I were to use a fire extenguisher, my dad would just get mad at me.

 

[ksouers]

Well for me, all those things are second nature. I did another firing of the boiler today, again just the outer shell. Water hose was about 3 feet away from me if anything went wrong. Like say the prototype oil burner I was testing, blew up sending hot oil lighting the grass on fire. The water hose is right there, if I were to use a fire extenguisher, my dad would just get mad at me.

That was good. That was a much better answer than your other one.

If your life or the house was in danger I seriously doubt he would get mad at you for using the extinguisher. Now, for starting the fire in the first place is another story...

 

[Circlip]

Not wishing to fan the flames but NEVER use water on an oil fire, play safely,
Regards Ian.

 

[tel]

As for the drain cocks, thats a good idea. Use steam to blow out any water at first. I will have to make a mark on the pulley to do that so I can get it between TDC and BDC on the intake stroke. Open the drain and warm up the cylinder that way, since the gas engine is designed to get rid of heat; I will have to insulate the cylinder. Work on that tomorrow.
Cost of this project so far, $0.00 I want to get costs to a minimum.

You're missing the point - the engine should run with the **** open and the action of the piston will pump it out. Have a look at video of a locomotive starting off - those white puffs coming from the cylinders are the result of the cocks being open

 

[rangerssteamtoys]

You're missing the point - the engine should run with the **** open and the action of the piston will pump it out. Have a look at video of a locomotive starting off - those white puffs coming from the cylinders are the result of the cocks being open

I dont think my engine will run with the drain **** open. I will have to test that today on air, put in a bolt that has a hole in it.

Circlip, the water was just to put out any fire, if it were oil, I have ashes left from a recent fire to throw on it. I tried it and it works well.

You guys have sure got me thinking about this boiler, I'm still going through with it but ALOT more cautiously. Back on the boiler, I have 1 coil of copper that is 60 feet long the other is about 50 feet long. I want to connect them together, how should I do this, with silver solder, flaring tool. What?

 

[rangerssteamtoys]

Well I have a system to coil the tubing, its essentially a 5 1/2" thick wall steel pipe welded down to a metal grate and strapped to a pallet, so I can move it with the forklift. We are going to do some testing with some short pieces of tubing and try to bend it. The first test ended up with a small coil but the copper was bent into an oval shape. Is this OK?? We are goign to try another piece filled with sand and hope that will keep the oval shape to a minimum. I plan to have 2 coils, I wrap the tubing into a coil about 20" long with about a 6 1/2" diameter coil and just wrap the next one right over top of the other. I need to join the tubing and have a 45 degree bend that will work, I will braze the 2 pieces together.

 

[Cedge]

Ranger
I'd use silver solder. Brass is not the ideal choice due to both chemical properties which allow dezincing and less tolerance for expansion and contraction.

Steve

 

[rangerssteamtoys]

Sandy suggested something called Silver Braizing. Regular silver solder that I have will melt very easy, its the cheap-o plumbers silver solder.

 

[Cedge]

Ranger
Terminology is the bane of all engineering. The Silver Brazing is the real "silver soldering". what you have is silver "bearing" solder with anywhere from 2 - 5% silver content. It's fine for most no pressure or low stress joints. The "brazing silver" version can have from 40 - 60%. Much stronger stuff. You're on the right track.... "Brazing" just didn't convey it.

Steve

 

[SandyC]

;D ;D

Hi Guys,

Steve.... yes it is the high silver content type I was suggesting, as you say terminology can be a problem.

Ranger... You must keep your tube as near to round as possible when you do the coils, otherwise you will run the risk of tube collapse under high heat and pressure.

Also, 5 1/2" - 6 1/2" ID for the coils is quite a tight radius for this size of copper tube.
If it is flattening to much then it may be advisable to fully anneal the whole roll first.
Heat it up to a dull red all over and then let it cool down. This will soften it and make it easier to form the bends with.... go easy though since it will be very soft in this state.

As you bend it into a spiral form it will work harden a bit.

Make the individual loops of the spirals with a gap/space between them of at least 1 tube dia.

The second row should also have the gap/space between the loops, but of course, with a larger inside dia.... again keep this to approx 1 tube dia difference all round (I.E. make the ID of the 2nd coil 2 tube dia's bigger than the first coil OD).

You must have these spaces to allow the hot gasses to get to as much of the surface of the coils as possible.

A half round wooden former, with say a 6" outside radius, having an angled semi-circular groove cut into it's outside (curved) surface (the width of the coil tube outside dia and half the depth of the tube dia) will make it a bit easier to form the coils and keep the tube round. It will also help if you have a second straight piece of wood, with the other half circle shape cut in it, to push the copper tube round the former.

You will need to get your Dad to help you with the SILVER soldering (silver brazing) since it will require the use of a reasonable size blow torch. (Silver solder (Silver Braze) with 40% silver content requires a temp of around 630deg C to melt and flow into the joints)

Making spiral tube sets is not the easiest thing to do, so take your time and work slowly.

Hope this makes things a bit more clear.

Best regards.

SandyC  ;D

 

[rangerssteamtoys]

The 5 1/2" pipe didnt work for a coiler, as you said. I tried it and it made the pipe in a nice oval shape. I'm going to try something like 6 1/2" diameter pipe.

 

[ksouers]

Ranger,
You may have to buy a conduit bender sized in the same diameter of you copper. The trick is trying to keep the "top" (outside radius) from flattening and thus kinking the sides. It's hard to describe, I hope you can visualize what I'm talking about. You can probably see it in your sample bending.

If you can't buy one, you can make one out of wood. I hope I can describe this sufficiently.

You will need three triangular pieces of wood. One piece is as thick as the diameter of your copper tube. You will have to cut a radius in one side of it, the same as the inside radius of your proposed coil. The arc of this radius should be about 1/4 of your coil circumference, maybe a little less.

The other two pieces of wood can be 1/2 inch plywood. You will want to cut them the same except the radius will be the outside diameter of your coil. Basically, the inside diameter of your coil plus the size of your tubing. Maybe just a little bit more, say 1/8-1/4 inch.

Fasten the two pieces of plywood to either side of your other wood wedge making a sandwich. You should end up with a pie-shaped wedge with a groove around the outside circumference of the arc. Now you will need a piece of heavy gage metal or stout plywood about 1 inch wide. Fasten that to one end of the arc.

Get a broom handle, paint roller extention, piece of iron pipe. Something stout to use as a lever. Drill a hole at the apex of the wedge radially. You now have a tubing bender.

Lock the free end of your tubing under the "bridge" and tail the rest of your tubing out along the groove. You can set this down on the floor with the handle pointing up. You should now have the tubing in the groove and pinched between the bender and the floor. Rock the handle, rolling the head of your bender on the floor. As the tubing is bent, rock forward and feed some more tubing then rock it back again.

Does this make sense? If not, I'll try to draw some diagrams for you.

 

[rangerssteamtoys]

Does this make sense? If not, I'll try to draw some diagrams for you.

I can't really imagine the bender your describing. I have an idea though, get a hole saw and cut about 20 wheels, screw the wheels down to a piece of plywood in a circular pattern to make the ID and OD of the coil. Have one opening where you can feed in copper. As it goes in the wheels will help it form a coil, to get the copper to raise up from the jig add some wedges near the end of the circular pattern. Just keep feeding in tubing and it should coil and raise at the same time.

I'm also thinking about just wrapping it around a bigger pipe, we tried a telephone pole that is used for a support beam in a barn. It worked great, but how to get the coil off? :big: :big: We have some extra poles to use but that requires alot of digging and cutting. I will do some more tests, see what works.

I would like to see some sort of diagram, please.

 

[ksouers]

You have to keep the sides of the tubing from spreading out. When bending, what you really are doing is stretching the outside bend of the tubing.

Take ride down to Home Despot or Lowe's and take a look at a conduit bender in the electrical department. You'll get a better idea of what I was describing. I'll try to have a drawing for you Friday night.

Here's a link to a bender at Lowe's:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=76063-1781-931B&lpage=none

 

[rangerssteamtoys]

You have to keep the sides of the tubing from spreading out. When bending, what you really are doing is stretching the outside bend of the tubing.

Take ride down to Home Despot or Lowe's and take a look at a conduit bender in the electrical department. You'll get a better idea of what I was describing. I'll try to have a drawing for you Friday night.

Here's a link to a bender at Lowe's:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=76063-1781-931B&lpage=none

Oh we have plenty of conduent benders (this is a construction company), we tried that and it didnt work either. We know some people who have copper tubing benders, we are trying to get them to bring them today.

 

[kvom]

I think you need to have the groove in the bender exactly the same as the OD of the tube. I've heard that filling a tube with sand can help prevent it from kinking when bent.