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Author Topic: I'm struggling with a DIY burner  (Read 17047 times)

Harry

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I'm struggling with a DIY burner
« on: February 18, 2010, 12:03:51 pm »
Hi All,

I quite new to this subject, absolutely new to the forum and trying to get an homemade burner working - based on this one - http://journeytoforever.org/biofuel_library/ethanol_motherearth/me11.html

Mine is a smaller version, I'm only trying to heat my home workshop and garage. I have used an old steel butane bottle,   12" diameter x 20" tall (excluding the valve). To it I have fixed a 3.5" square flue close to the perimeter of the top of the bottle, coming out at a small angle to the vertical and protruding a little way at one side into the stove (like a scoop) of 10' feet total lenth. For an air intake I fitted a 3" diameter pipe vertically at the top centre of the bottle, to this I have just added an adjustable intake damper. Down the centre of the air pipe I have an 8mm pipe dripping oil down onto the burner plate.

On one side of the bottle I cut a hinged door, soon to be fitted with a mica window. For the burner I mounted a 5.25 diam x 1.25 aluminium block with the top turned into a dish roughly as per the desciption on the above web site. For the feed pipe I used 8mm OD copper pipe as I felt the 1/4" pipe might be too narrow and let this gain some heat by placing it close to the flue.

Prior to my making the burner, I tested it with wood and it worked quite well. Then I tried it burning wood with WVO dripped down onto the wood - again it worked well and the beast ran for much longer without needing any attention. No matter what I used, I could never get the bottle upto red heat, the best I managed was about 400 deg C. There has been no smoke or much in the way of smells emitted, irrespective of what I have tried to burn.

Having got the burner completed I tried it for the first time burning only WMO. This has not been so successful, but it has burnt and keeps burning.

This last is what I am trying to solve at the moment and hopefully get the stove to produce red heat. I started with the air feed pipe about 5" above the burner dish and it burnt with a slight roar. I then lowed the end of the air pipe to about 1" above the burner and the noise increased, but the bottle temperature didn't increase very much. I could not get the oil to burn at all, unless there was some sort of wick laid on top of the burner (burnt off cardboard or paper etc.).  This seems to suggest to me that the burner dish is not getting hot enough to vaporize the oil(?).

I think an air feed blower might help, but I'm trying hard to avoid the need for any electricity to be needed to run it. The WMO I'm currently testing with is a gallon of unused (what is suggested to be) synthetic. I have only burnt a couple of pints of this so far - I have a few gallons of mixed used WMO which is as yet untried.

I have set up some photos of the project on my persoanal web site ( hope there is no objection to an external link?)

http://myweb.tiscali.co.uk/m1byt/stove/Picture1.jpg

http://myweb.tiscali.co.uk/m1byt/stove/Picture2.jpg

http://myweb.tiscali.co.uk/m1byt/stove/Picture3.jpg

http://myweb.tiscali.co.uk/m1byt/stove/Picture4.jpg

http://myweb.tiscali.co.uk/m1byt/stove/Picture5.jpg
Any suggestions are welcome.


tightwad nik

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Re: I'm struggling with a DIY burner
« Reply #1 on: February 18, 2010, 01:04:52 pm »
i tried something similar to list a long time ago, i think you need the pipe for the oil feed to be longer down your chimney that way  the oil would get hotter before dropping into your dish , maybe coiling it around a pipe first (fill with sand before bending it works well) extra heat for the oil and would need a quick blast of compressed air once a week/day to clear any debris, also the chimney i would put closer to your dish, get some flat sheet roll it up and put it inside your chimney letting go it should expand to be a snug fit and then lower it closer to the dish to create more of a draw that should heat things up, but not too close to the dish as this would cool things by having cold air pass the dish, hope this helps and if you dont understand and need pics i can knock some up for you , cheers nik

Harry

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Re: I'm struggling with a DIY burner
« Reply #2 on: February 19, 2010, 05:22:05 pm »
Using the idea on this site - of just using the base of the gas cylinder as the burn surface, tonight I managed the best/hottest burn so far. The bottom of the cylinder was covered in ash from my lighting up the burner before, so by way of an experiment....

Onto the ash I put a small (around 5.5") cast-iron frying pan and fired it up - soaking a single sheet of newspaper in oil and lighting it in the pan. The oil had already started to drip from the feed. The pan was insulated from the cylinder base by the ash it sat on.

It lit up quickly and burned well, but burned even better (and noisier) as before, if I lowered the air intake pipe down to an inch or so above the surface of the pan. Stopping and restarting the oil flow, it would reignite just from the heat of the pan - so that is definitely getting hot enough to vaporise the oil. The paper burned away quickly which proved it can burn now without needing anything to act as a wick for the oil. Heat was such that it hurt to hold my hand any nearer than 6" from the surface of the cylinder - not quite red heat, but certainly not far off. The need to have something to act as a wick before, was what concerned really concerned me the most.

I made the copper feed pipe, so that it was only around half an inch short of the bottom of the air feed pipes length. The copper pipe is getting so hot, that the oil comes out of it already burning - so I guess I need to shorten it back a bit to prevent this. My air pipe is about 2' long and the oil feed copper pipe enters through the side of the air pipe about 3" down from the top. I was previously getting some slight burning of the oil as it dripped out of the air pipe, but now it comes out in a solidly burning stream - which I think is wrong.  

I have not yet tried the suggestion to extend the flue further into the chamber.  
« Last Edit: February 19, 2010, 05:25:19 pm by Harry »

tightwad nik

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Re: I'm struggling with a DIY burner
« Reply #3 on: February 21, 2010, 03:01:35 am »
by putting a pan on the ash you are doing the same as increasing the flue into the burner, the air is rushing in close to the flame and causes a more intense draw around the flame, and thats what you want, if the oil is burning before it comes out the its too hot and you will get some varnish/soot/gunk build up in the pipe you could shorten it and drop the oil from a height, but the air/heat travelling in the opposite direction may cause splatter on the inside of your flue, so you need to maybe bring the oil feed in lower down, or maybe make it wind down the outside of the flue after all if the pan is getting that got you might not need to do too much preheating, good luck

Harry

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Re: I'm struggling with a DIY burner
« Reply #4 on: February 28, 2010, 10:18:28 am »
I have just managed to get more heat from it, than I need....

I have just managed red heat on the gas bottle casing at last.

It seems an inadequate oil flow was probably the cause of it not producing enough output before.

Latest changes are a mica window fitted in the door, so I can see what's happening inside at the burner, rather than peering down the air pipe. Then I fitted an 8mm compression T in the feed pipe to enable the thing to be fed from two separate header tanks. The single pipe down from the T was close to the flue, so warm anyway and making the oil flow easily. One tank had MVO and the other WVO - I previously found that these would not mix in the same tank, but no reason why both cannot be fed into the last section of warm pipe to mix.

The burner was just an old small cast iron frying pan about 5" diameter, sat on top of a bit of 3x3 steel box section, both placed on the inside bottom of the gas bottle.

Prior to today's test, the oil had been dripping into the pan and immediately vaporising. Today, with both oil sources turned on and more flow, a pool of oil actually built up in the pan and this seems to be the secret to getting heat from it.

My IR temperature unit measured temperatures beyond its range (>650 deg C) around the mid-point of the gas bottle, 350 on the flue and a definite red glow from the gas bottles steel casing. With outdoor temperature at 3.5, the temperature in my workshop quickly got up 30 deg C - at which point doors had to be opened to cool it down.

I previously found it ran best, with the end of the air pipe about 1/2" above the bottom of the pan. With more oil going in, this height had to be changed to 1.5" above the pan to enable increased air to for the extra burning taking place.

This all suggests that 1/4" is not big enough for a gravity oil feed, I used 8mm (3/8"), but even 8mm is not big enough if the oil is cold enough that there is a need for heating - unless some means can be found to preheat the oil in the tank or increase the head. I am working with a 5' head using small test tanks.

The next thing to do will be to swap the cast iron flat bottomed pan for something which slopes down to the centre, to concentrate the oil in the middle.

Lighting this thing is real easy and clean...

Turn the oil supply on, pour a cap full of parafin (kerosin) down the air pipe into the pan, open the door, close the air-in damper and iginite the parafin - the rubbish in the pan from the last use, acts as a wick until the flame can self sustain itself. Quickly shut the door and open the damper. Five minutes later you have heat flowing.

Turn the oil off and a minute or so later the flame goes out. A slight fall and then rise in the oil feed pipe not far from the burner, means the flow will stop and start even quicker - rather than continueing to flow by syphonic action.   

    


« Last Edit: February 28, 2010, 10:29:40 am by Harry »

Patch

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Re: I'm struggling with a DIY burner
« Reply #5 on: August 19, 2010, 05:36:09 am »
Harry,
         Ive built my heater out of the same style cyclinder, I to have much trouble getting a decent amount of heat from it. It has a 6inch steel plate burner which is dished and sits an inch off the bottom of cyclinder. The vent pipe is approx 1 1/2 inch abve burner, Ive played around with 1/4 & 3/8 copper feed tube at various hights. It will continue to burn all day or night but continues to smoke and fails to produce heat. Ive tried some of your sugestioins but still things are not right. Any tips would be great

Harry

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Re: I'm struggling with a DIY burner
« Reply #6 on: August 19, 2010, 10:58:41 am »
Harry,
         Ive built my heater out of the same style cyclinder, I to have much trouble getting a decent amount of heat from it. It has a 6inch steel plate burner which is dished and sits an inch off the bottom of cyclinder. The vent pipe is approx 1 1/2 inch abve burner, Ive played around with 1/4 & 3/8 copper feed tube at various hights. It will continue to burn all day or night but continues to smoke and fails to produce heat. Ive tried some of your sugestioins but still things are not right. Any tips would be great

I'm not by any means an expert (or even an amateur) on these things, but what I noticed was....

It seems to work better and produce less smoke if there was some crud on the dish to act as a wick for the flame, so I stopped cleaning it. I also noticed it would produce much more heat if the oil over spilled the dish and there was some crud in the base to act as a wick, where upon the base would catch fire. I am not sure what actual oil I am burning, other than it is a general mix of waste oils and probably mostly old engine oil.

It isn't without any smoke, but it does for the most part burn with little noticeable trace of smoke. One modification I started to make towards the end of last winter, was a hinged 1/4 steel plate so it could sit above the burner and around the air pipe in the middle. Hinged, so it could be folded to be able to get it in there via the door - so it would form a V shape along the hinge between the two steel plates. The idea I had in mind was to make a secondary chamber at the top, where it might get a second chance to combust and burn the smoke off and to cause the heat to rise around the outer wall.

I only got as far as hinging the two plates, I still need to cut them down to shape to fit it. So I don't know if that might work or not yet.