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Author Topic: Thermal conductivity of 2" exhaust pipe.  (Read 13305 times)
glort
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« Reply #15 on: April 20, 2013, 01:38:11 AM »


Thanks for the very helpful input. Certainly plenty to think about and investigate.

Jens,
I think I understand what you meant with the drums.
I help a friend make Boiodiesel half a dozen times a year and part of that involves heating and drying  the oil before processing. My friend used to cau 44 gallon drums in half and sit the 20L drums veg oil comes in here on top of the fire. Eventualy they would boil and the water would be driven off. Generally took an hour for an average oil/ water quality drum.

Looking on the net I got to thinking about the sides of a drum being a much larger area then the bottom.  I got a 60L drum, cut a hole in the bottom so the wood for a fire could be put in there and drove a bit of rebar about 1/3rd the way up so the 20L drum could be inserted and suspended.  I rested it out and could get a drum of oil to boil in about 5 min flat and the thing dry in about 20. It was a massive difference in speed and efficiency.

I took this engineering marvel over to my friend and he laughed..... Right till the time he saw how much faster the oil boiled and the heat going into it.  We made 3 similar boiler drums in the end which was as many as we could keep up with.
As production volume increased, I made the burner in the vid so we could go back to the brute force method.  We are going to get another drum,  take the ends out  split and open it up it to encase the Middle drum to0 make that more efficient. I can boil a drum of oil in 17min now, it would be awesome to achieve that in 5 Min!

Efficient it's not ATM but it serves 2 purposes.  Between my friend, his sons and all their girlfriends, they service about 8 vehicles at his house so it generates quite a bit of used engine oil. He always was running to the tip to dispose of it and they only allow so much per trip.  Now we use it to fuel the burner which saves him going out of his way ( well and truly) to take it to the disposal place and drys and heats the oil for Bio making.


Ronmar,

I googled the CSST and can only see one place listing it here but I'm sure it's available more widely.  I'll ring around during the week and see what I can find and how much it is. I also see a listing for galvanised instead of stainless which might be good for testing things out initially at a lower cost.  If it works well I'll use the gal till it fails and then get the stainless and build in whatever improvements become obvious.

Failing that I have had one more brainwave.
I'm thinking of a central Square tube running say 3/4 the way up the drum. From each side of the square tube I can cut holes in it and weld a bit of round tube on which has been pre bent with a simple Bender at 90o to come out from the central tube wand using multiple round pipes,  to form a branch structure much like a tree.  I'm thinking if the pipes come out and then go at and angle ( say 45o)rather than straight up, that may help efficiency as well.  I may also be able to put some staggered bend in the pipe,  small angles and straight sections to get the pipe to run round the drum a bit  making for less holes and welding and greater surface area.


I hope I can get the stainless or gal corrugated pipe cheap enough because I could use a smaller, say 1" diameter of that and weld it to a branch to use say 4 separate pipes to get the flow and it would be so easy to coil inside the drum and surround with water.  I see on the info I found they say it's good for exhaust use and withstands 500oC with no problem so in this application where it is kept relatively cool with the water on one side.  it should have no problem standing up to the Mega blowtorch.  :0)

As a side note, I have looked at so many Vids on Youtube and there are a Myriad of waste oil burners on there.
It's also apparent that while a lot of these buners work, they are really only good as shed heaters because the way they work makes putting the heat to work other than air heating, a very difficult proposition.
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glort
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« Reply #16 on: April 20, 2013, 01:46:05 AM »

Hi, thanks for the video...the easiest thing to do with your technology level is to find a used boiler, or gas fueled water heater and run the burner into the boiler's firebox. Failing that...use or make some sort of water tube boiler.

Yeah, That was my first thought... about 3 years ago. I wanted to get an old gas pool heater which is about the most common type boiler here and pull out the burner and stick in the oil burner.  I could fire the flame down a length of tube with one end blocked with holes drilled in it to spread the heat and replicate the gas burners more closely.

Unfortunately about the closest I have come to finding an old gas boiler of any kind like that is to get the actual Heat exchanger out of one but it takes weird Diameter pipes with special Expensive flanges and is heavy as hell.  Building a housing for it would take a bit and then there is the problem of insulating it.
If I come up dry on all the other concepts, I might have to revisit that.
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Jens
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« Reply #17 on: April 20, 2013, 03:16:03 AM »

I also see a listing for galvanised instead of stainless which might be good for testing things out initially at a lower cost. 

Just a couple of cautions here:

Galvanization burns off at a pretty low temperature producing a TOXIC white gas. It is extremely important that you keep this in mind while welding and in your test burners. I don't foresee a problem with water on the inside but it could theoretically form large air bubbles allowing excessive localized heat.
Welding galvanized stuff usually makes a mess of the weld unless the galvanization is removed. Exhaust components are usually aluminized giving rust protection and the ability to weld stuff together.

Danger Will Robinson! Danger! Danger!
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Ronmar
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« Reply #18 on: April 20, 2013, 01:24:13 PM »

Finally got around to looking at your video, that is a pretty impressive burner.  I am using a babbington burner to heat my garage.  Here is a vid of the first one I built.

http://youtube.com/watch?feature=plcp&v=3ACukFExR4I

 I made up a welded finned pipe(fins on inside and outside) about 6' long with a 6" ID.  That sets inside an outer tube.  The burner end of this thing sets in my garage. I run the burner thru the inside pipe and pump outside air in thru the outer pipe with a squirrel cage blower.  I get a large volume of 250F air pumped into the garage.  Heats it up from 30F in about 20-30 minutes. 

I am in the process of desiging us a new ICF home with radiant floor heat.  That is why I have been looking into ways to heat water with this burner or the output from a chip/pellet burner.   
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Ron
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glort
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« Reply #19 on: April 21, 2013, 01:14:31 AM »


That's a Nice, neat and practical design.

My mate had one for heating his oil . Just the dregs of the Bio and the compressed air Feeding into A copper T piece and another bit that was flattened to make a spray Nozzle. He used to blast the flame through an old gas water heater that was lying on it's side. We calculated it was putting 33Kw of heat into the oil he was pumping through which wasn't bad.

The thing I don't prefer about Babingtons is that you need a compressor running to feed them. My mate wore out a couple before I came along with the fire drums then the oil burners.
I have always had this thing about heating my pool with waste oil so always was looking for high output designs and long run times.  I am looking at smaller ones now but am actually finding them harder to build and operate than the big ones.
I have got one little one going, I put controls on the air as well as the fuel so the air can be stopped down to prevent overcooling of the burn chamber which brings an end to the show on my designs.

One thing you may care to look at one day is doing away with the compressed air on your design once its running.  Heat it up as you would normally then if you lengthen the output tube and preferably make it a heavy gauge and then put some bits of pipe laying inside of that, they will act like glow plugs and you can just squirt the oil in and used forced/ blown air. It vaporises the oil on contact with teh hot bits of metal and will self sustain very nicely.  Quieter and less energy to use a blower than a compressor.

I did one that had an internal switchback. It was a beast. Had to warm it up on gas then switched to oil and off it went. The more you turned it up ( slowly) the hotter and better it ran. I never got the thing to full tilt. I ran it connected to an electric leaf blower one time  and had the oil drum on the shed roof but it needed more fuel pressure as it was making too much resistance to the oil to flow quick enough.  I must drag that thing out one day and fire it up using a small diaphragm pump.

I'm very interested in Different burner designs, maybe there could be a section for people to post different ones up. Would be real interesting to see them.
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Ronmar
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« Reply #20 on: April 21, 2013, 11:57:45 AM »

Mine dosn't hardly use any air.  I am injecting the air thru I think a .015" hole at 25 PSI.  My compressor does not run constantly as the airflow is so small.  It might cycle and top off the 25 gallon tank once every hour or so maybe?  The air IS what atomizes the oil that flows down over the nozzle hole, so I don't think I want to do away with it.  In fact, air is the only thing I use to power/control the burner.  I have a 3 gallon pressure tank from an old air horn system that I put my fuel in.  It is stood on end and the outlet at the bottom is tied to the burner with a 1/4" ball valve for on/off control.  I apply very low pressure compressed air to the top of the tank(less than 1 PSI typically) with a regulator.  I regulate this air pressure to control the burner output.

I didn't want a tall chimney on this heater since I wanted to be able to move it fairly easilly(it is pretty heavy).  Since the heatex is so long and the chimney on the end is only about 18" tall, I added a 3" computer fan in to apply a little bit of draft air at the burner end.  It is all run thru a plate that the garage door closes down over.  I will put up a pic of it later... 
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Ron
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« Reply #21 on: April 21, 2013, 01:32:39 PM »

Obviously you guys are approaching the moon and I'm still pretty fascinated with the teeter-totter.

Too much power to feed an on-demand water heater?  Maybe ducted back a couple of feet?

All that heat is coming from WVO and a high volume fan?

Casey

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Ronmar
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« Reply #22 on: April 21, 2013, 05:16:54 PM »

Here is my garage heater and fuel tank. The smaller pipe down in front is the added draft air coming from a 3" computer fan mounted at the plate.



Here is the outside end with about an 18" chimney.  Hot gas passes up the inner tube and turns up thru an elbow and out the exhaust. Fresh outside air is pumped in around the outside of the heatex pipe and exits around the burner.



There are two regulators mounted on top of the tank. One where the air quickfitting is, gets me 25 psi for the burner nozzle.  The larger silver one is a lo pressure reg that gives me my fuel pressure air.  With motor oil 3/4 psi has been about the sweet spot.  The fuel exits at the bottom passes along the pipe and thru the coils located in the hot air stream where it get preheated before streaming down over the nozzle.  For lightoff I preheat the coils and burner body with a torch, then put the torch in thru a access cover and turn on the fuel valve and away she goes...  I startup the outside air blower after about a minute so it only blows warm air.  After a run it continues to blow warm air for about 10 minutes after I turn off the burner.

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Ron
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glort
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« Reply #23 on: April 21, 2013, 10:23:11 PM »


Thanks for the pics and Info. That gives a thickhead like me a much better idea.
That is a very original design. Never seen anything like it before. Also nicely efficient.

I was also under an incorrect impression with the Babbington. I had no idea they could use that little air. It makes a big difference to my impression of them. Going on that, I can see how such a system is very practical.   

I wonder if it would be possible to generate a worthwhile amount of air pressure for one ( even a small one) with one of those mega Fish tank air pumps?
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glort
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« Reply #24 on: April 21, 2013, 11:10:02 PM »

Obviously you guys are approaching the moon and I'm still pretty fascinated with the teeter-totter.

Too much power to feed an on-demand water heater?  Maybe ducted back a couple of feet?

All that heat is coming from WVO and a high volume fan?

Casey



Comes from years of wasting time mucking round when I should have been doing more purposeful things in my case.
The burners I make now are technically Illegal in my part of the world. You have to have burners inspected, certified and licensed if they do over 500,000btu.
 I can triple that pretty easy.  :0)

Burning oil and burning it clean aren't that difficult when you work out a few simple things.
First one for me was heat.  In my non atomised designs, you have to get the oil Output Hot and keep it that way so it changes from liquid to a gas.
You can't just do that in a coiled bit of 1/4" copper pipe, it will foul up in minutes from the residue any waste oil will leave behind. You have to do it in a chamber where it will either be blown out as invisible ash or burned out as carbon.

Second one was air and secondary air.
Anything will burn clean if it is mixed with enough air.  I was Burning some styrofoam the other night as a test and got that to burn clean. Sure burns hot as well.
You either have to supply an excess of air without overcooling the fire or you  have to supply more air after the initial fire.
A lot of people thing of Burning oil as like burning tyres in the open, it just dont work that way.  That said, I have often done the mental arithmetic of a tyre burner. There would be a lot of heat in that and shouldn't be hard to build a burner you loaded once a day and kept your home plenty warm for 24 hours. 
If you built the thing so you could put them in whole there would be no processing like splitting wood and there would be endless sources giving you more fuel than you could possibly use.
Done right, there wouldn't have to be a bit of smoke or small though.

I have seen a load of different ways of burning oil  and I have also seen some designs that appear more prevalent in different localities than others. The Japanese seem to have a design that is popular and the Russians another from what I have looked up.  They all work, just in different ways. Some are passive, no external energy required, and others are active with fans or compressed air etc.

To me the trick is getting the heat to do the work you want.
I have seen endless vids where people burn the oil out in the yard, Putting it to work in a practical, safe fashion as Ronmar has is something quite different.
Burners can be simple as hammers as well.
I have one I use in My wood fire Pizza oven when I'm not allowed to burn wood.

The thing is literally a 2" bit of exhaust pipe with a 1/4" Bit of copper pipe coming through the side. It's just stuck through a hole I drilled in teh 2" pipe. I use a small blower form a car to power it.
I light this up on gas and have it aimed a a few bricks strategically placed  at the end of the burner. After about 5min when things get hot, I slowly turn on the oil and watch the flame build and when it's running hard after a couple of Min, I turn the gas off. The bricks glow red ( near white if you crank the thing and leave it and hour or so)  and evaporate the fuel. By the time it's really cooking, the oil seems to take 3 forms.

Some light fractions burn like a gas as soon as they hit the hot tube and burn with a blue flame. The next phase turns to whit vapor and ignites soon after it leaves the burning tube and the 3rd phase is liquid oil which burns on contact with the hot bricks. I see the exact same phases when running my turk style burner.

The thing is, this Burner is a steel pipe with a hole drilled in the side and a bit of copper pipe inserted to feed oil into the thing.
I couldn't imagine anything simpler except if you fed the oil from the end and didn't have to drill the hole!  :0)

For me this all really comes down to going against the grain and making good use from a free waste product.
 I get a lot of satisfaction out of that.

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Ronmar
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« Reply #25 on: April 22, 2013, 05:37:16 PM »


Thanks for the pics and Info. That gives a thickhead like me a much better idea.
That is a very original design. Never seen anything like it before. Also nicely efficient.

I was also under an incorrect impression with the Babbington. I had no idea they could use that little air. It makes a big difference to my impression of them. Going on that, I can see how such a system is very practical.   

I wonder if it would be possible to generate a worthwhile amount of air pressure for one ( even a small one) with one of those mega Fish tank air pumps?


I have heard of people running them on old reefer compressors.  A fish tank compressor might work as it is a pretty small volume of air...
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Ron
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« Reply #26 on: March 26, 2016, 06:26:54 PM »

There will be less sooting problems if the water leaving the exhaust heater exchanger is about 205F. Exhaust's first contact with the heat exchanger should be adjacent to where the hot water is leaving the heat exchanger. 
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vdubnut62
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« Reply #27 on: March 31, 2016, 02:07:24 PM »

Mine dosn't hardly use any air.  I am injecting the air thru I think a .015" hole at 25 PSI.  My compressor does not run constantly as the airflow is so small.  It might cycle and top off the 25 gallon tank once every hour or so maybe?  The air IS what atomizes the oil that flows down over the nozzle hole, so I don't think I want to do away with it.  In fact, air is the only thing I use to power/control the burner.  I have a 3 gallon pressure tank from an old air horn system that I put my fuel in.  It is stood on end and the outlet at the bottom is tied to the burner with a 1/4" ball valve for on/off control.  I apply very low pressure compressed air to the top of the tank(less than 1 PSI typically) with a regulator.  I regulate this air pressure to control the burner output.

I didn't want a tall chimney on this heater since I wanted to be able to move it fairly easilly(it is pretty heavy).  Since the heatex is so long and the chimney on the end is only about 18" tall, I added a 3" computer fan in to apply a little bit of draft air at the burner end.  It is all run thru a plate that the garage door closes down over.  I will put up a pic of it later... 

Ronmar,
 If you don't mind my asking, how do you manage the "runoff" ?(a better term doesn't come readily to mind) of the excess oil from the Babington nozzle?
That has always been the hitch that stopped me from building a Babington burner. IIRC years ago as a boy, the article ran in either Popular Mechanics or Popular Science, of Mr. Babington and his nozzle - his first was a cast iron shift knob with a slit hacksawed in it.
Ron.
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