This picture shows the air tube/pedistal mounted in the stove.

Info -- In this picture you can see the discoloration on the outside of the burner tank below the door opening, this is caused by wasted tiny oil droplets dripping down the inside of the door and eventually running down the outside of the burner tank. The oil is coming from a small amount of the very tiny oil droplets that explode from the burner bowl when the main fuel droplets hit the hot bottom of the burner bowl. This small amount of fuel is not being burnt as heat so is completely wasted now, I need to make changes here, it may be that the 12 inches that my fuel droplet falls is to large of a distance and is causing this excessive fuel splash, don't know yet, this particular stove design does not allow me to easily change the drip tube length so this testing will be put off for a while.

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This shows the burner assembly located in the stove.

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The first burner assembly I fired up was using only outside air from the new lower air inlet, there were no holes put through the side of the lower burner can, seemed to work initially but the burner went out 12 hours later. the burner bowl had about an inch of bubblegum like black sooty tar in it and the upper lip of the burner bowl was coated with a thin layer of black ceramic type stuff. I assume the outside air cooled the bowl off enough that the oil did not vaporize well, I think the ceramic stuff was caused by liquid sooty veg being carried by the flames and condensing on the lip of the bowl, don't know. but it took scraping with the edge of a pocket knife blade to remove this from the rim of the bowl.

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When I first fired this burner up I had the lower air damoer completely closed for the first hoiur to allow the stove temps to stabilize, I then slowly opened the damper to allow more oxygen rich outsaide air to the burner bowl

This picture is of a butane B-B-Q lighter flame being bent 90 degrees and drawn into the lower air inlet tube with a good draft. This is a poor picture due to contrast of flame brightness but if you look at it for a bit it is seeable.

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It did not seem to make any differance if the lower damper was partially or fully open so I set it full open during the 12 hours the burner was burning. The flame from the burner bowl was impressive during the first couple hours that I monitored it closely. In the following pictures you can clearly see the fingers of flame that are coming from each of the 1/8 inch air holes in the burner bowl. The fingers of flame from these holes is a much lighter brighter yellow than the flames from the main part of the bowl, no blue flames were seen but since there were no visable flames coming from these holes before adding the outside air I suspect that considerably more of the fuel vapor is now making heat than before adding the extra air?

The flames in these pictures are more orange than normal due to the draft through the stove being disrupted because the burner tank door is open, the flames become much more bright yellow once the door is closed and the normal draft is reestablished.

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Another flame picture.

You will notice that not all the holes have flame in these pictures, the flame comes and goes randomly from verious groups of holes, I assume it depends if there is fuel vapor present close to the holes, something else to do testing on.

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One more picture of flames.

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I changed the lower burner can to one that allows both hot inside and cool outside air in under the burner bowl. This can has 3 half inch diameter holes drilled through the side of the can about 1 1/4 inch up from the bottom as well as a 2 inch hole in the center of it's bottom. I have the lower air damper set only about 1/3 open now and there are nice flames randomly coming from the 1/8 inch holes, the bottom of the burner bowl has it's normal very thin film of bubbling oil along with the tiny fuel droplets that are created when each main fuel droplet explodes when hitting the hot bottom of the burner bowl. The burner has only been burning for a few hours now so don't know how it will do long-term yet?

With the colder weather setting in I have been burning over 1 quart of wvo per hour. I always use oil that I get in cubbies and is pretty dry, I have never had to filter it at all to burn in my heater. All I do is poor it through a big funnel in witch I put a screen out of one of those screen cover things that you put over a frying pan to keep grease from splattering out.
Last weekend a had a brainstorm on an addition to Tims new burner assembly. I cut the bottom of a butane can (used for refilling lighters and such) about an inch up. Then I drilled 2 small holes in it just big enough to put wire through it and I hung this thing in the middle of pet dish by running wire through the small holes in the pet dish. My idea was to let the drip fill up the little cup as it preheats the oil in it and when it fills I wanted it to spill out and refill. Well I could not get the design right to make it tip so I fired my heater thinking the oil would pre heat and just boil over into the pot. Wow! The oil in the cup gets so hot it looks like foam and the flames coming out the small holes in the pet dish are hitting the cup perfectly. With this set-up I am able to run my 3" air inlet at the top of the heater wide open with out a flame out. Its like a torch with very bright flames. I have been running the air at half covered. After 24 hours I shut the oil off to see in the pot better after the flames got smaller and the pet dish was still very clean and the cup as well. The end of my dip tube is a 1/4" flare cap with a small hole in it. It is almost even with the bottom of the air inlet. The nut has been building up with crude and flaming I don’t think this is bad as the crude burns off then re forms.
Today is day 2 of continuous burn, and still putting out good heat with a clean burn— it is minus 10 degrees this A.M.
If I continue using the cup it will probably be made out of a copper cap from a1" or 3/4" sweat fitting.
What I used was all I had at the time and Im surprised it didn’t melt (aluminum).
I have used same type heater in the shop to heat and filter over 1000 gallons of wvo. It has 50 feet of 3/8" copper tubing raped around the hot spot of the heater(insolation over copper tubing by hot spot) and is pumped into a 80 gallon tank. In 2 and ½ hours the temp of the oil goes from 70 to 150 degrees (70 gallons) and uses about 2 gallons of free wvo or motor oil. At this point I cover with 2" of insulation and let sit one week, the whole tank is insulated very well. It gets no other heat during this time. Then I transfer the oil to the other tank all but the bottom 5"s. It gets heated again (150) and filtered through 5 micron. The filters stay clean a long time. All my plumbing is copper, and have no problem with any POLLY going on.( As of yet) Oil stays in all the lines at all times. The clean oil is stored in a 275 plastic tank.
Tim keep up the awesome work!!!

quote:

Originally posted by Tim c cook:
Slightly angled view better showing the damper.

ok.... so air comes in the bottom and its volume controled by damper plate. Got that.

Where does the air go? I see no exit for air. Only an entrance.

Tim your flame "fingers" look just like mine with lots of air from below. I ran for 3 days on the 1.4qt bowl, and made a new one with a 2 qt, 8" diameter bowl, and put 12 1/8" holes lower in the bowl, about 1/2" up from the bottom. This burns better than my other one with 16 holes. This could be due to a 1" larger bowl diameter, but I think lower holes is better since there are more flames lower inside the bowl to heat it up. This may be the effect you get by providing all air from above, it forces the flames down into the bowl, but most of my air is from below.

I think the best number of holes needed (and airflow) is determined by the burn rate. If I have a small-medium rate (6-18" flame height), then less holes is better since it gets higher velocity air through them and makes more yellow flames and more blowtorch sound. When some of the holes have no flame fingers, the air rate seems below optimum, since it makes more soot, probably due to that part of the bowl cooling.

So it may be best to have different bowls for low rate and high rate and swap them for different outdoor temps when you need a higher rate. This will be my next testing. I started with low number of holes, since its always easier to add them than subtract them.

you might stack your two bowl in the burner if they fit tight enough. Ararnge holes in them to where when sitting stacked one way each bowls holes line up providing max air. Turn the inner bowl a 1/4 inch and it aligns new (but fewer) holes.

Turning a hot bowl though may be physically harder then pulling one out and replacing it. Then again though if you can figure that out you would not have to shut the heater down just to change air holes.

quote:

Smoke tester -- Don't know what this is, how does it deturmine smoke amounts? There is a small amount of smoke visable coming from the chimney but not much, it is just a wispy amount that is totally dissipated within 2-3 ft from the top of the chimney, you have to deliberately stand still and watch the top of the chimney to even see it.

It's a hand pump suction device that draws a calibrated amount of exhaust gas (by the # of strokes) through a piece of white paper, after which it is compared to a chart with diferent smoke readings.

Judging from the amount of carbon and crud in your pics, my guess is it is not burning very clean compared to a pressure nozzle or siphon nozzle type burner. There is a lot to be said of the vaporizing burner since it is able to make good useful heat without the complexity and the much higher elec demand that a pressure or siphon nozzle burner requires.

It seems having a hot and well insulated burn pot helps with a cleaner burn. Have you seen these stainless double layer soup bowls? You can fill it with boiling water and it is insulated well enough so you can hold it with your bare hands. I bought 2 of them but sadly still have not started on my pot burner project yet.

Last weekend I built my own dog-dish Cook burner assembly and tested it in my woodstove. While there was a second heat source it worked great. Once the bed of coals burned out though, the Dog-Dish burner would not generate enough heat to burn cleanly. Nevertheless, it was a simple way to augment my wood supply, and raised the shop temperature about 20 deg on 1 gallon of oil.

With external heat, the flames from the holes were blue, shading to yellow at their tips. No visible smoke issued from the chimney until the coals died out.

It's all about heat management.
Cheers,
JohnO

Stove operation -- The stove operation has not changed with the addition of the bottom air. I light the stove by closing the upper air damper down to slightly open, then set the flue damper to completely open, then light the 1/2 cup of startup fuel in the burner bowl (95% diesel, 5% E85), the optical flame detector automatically starts the drip once it sees flame. The cold stove will "chuff" smoke at starup if the top air input is too far open. The initial fast hot burn gets the stove up to temp in about a minute. After a couple minutes the stove is warm, I then open the upper air damper til the flame becomes erratic, then close it down a bit til the flame stabilizes, I then close the flue damper til the flame starts to turn more orange, then open it up a bit til I again get a nice bright yellow flame, a couple cycles of both these dampers finally gets me to a nice stable bright yellow flame.

The damper setting of the lower air input does not seem to make any differance to the amount of flame fingers from the air holes, there is no flame with the damper completely closed but flames show up when the damper is about 1/4 open, opening it further makes no change in the amount, or length, of the flame fingers, I suspect it is the size of the holes in the burner bowl that limit the amount of air going through these holes. There are bright yellow flames coming from the air holes at least 75% of the time, looks promising.

This new burner seems to be putting out the most heat of any test so far. The outside temps took a dip again yeaterday and I had to turn up the drip rate a bit. With the prior fuel drip setting of 134 drops/min (6 sec/rev) into the external-air-only-burner the hottest part of the tank stayed around 300 deg f, with the cooler outside temps and this latest burner I upped the fuel to 145 drips/min (5.6 sec/rev), this is something like a 7-8% increase in fuel but the tank temp went up far more than 8%, the temp is around 380 deg with this new in/ex burner unit and the hottest point on the tank has moved down the side of the tank about 3 inches. Originally the hot spot was 18 inches up the tank, now it is 15 inches?

The distance between the top of the burner bowl and the bottom of the upper air inlet tube was 5 1/2 inches with the 13 day burner, when I installed the new air tube pedistal I adjusted it so the top of the new test burner bowls are 6 inches below the bottom of the upper air inlet tube, it may be this 1/2 inch change that has lowered the hot spot, don't know.

Soot in stove -- The pictures look worse than real life but there is a good bit of soot clinging to the inside wall of the burner tank, this has a lot to do with the fuel droplet splash situation, some percentage of the tiny fuel droplets splash up high enough to be carried out of the burner bowl by the top air as it blows down and out over the top of the bowl, these droplets end up as crusty deposits on the inside wall of the tank, the crusty stuff tends to collect soot, I keep looking for deeper bowls but have not found anything acceptable yet, work in progess.

harry3 -- The tiny suspended hot bowl sounds like something worth more testing, I will try it eventually, way too many things to change on these burners for now. Hopefully you folks will pursue some of these changes and post the results here so we don't have to duplicate efforts too much.

sunwizard -- Now that I have the lower air tube installed I will be trying all sorts of hole patterns and sizes, as long as my local farm store keeps the 1 qt bowls in stock.

canola -- I think the smoke tester is a bit overkill for now, I admit these vaporizing-type drip burners do put out a visable bit of smoke, a lot more than any pressure/syphon burner, but for me the simplicity and silent operation is an acceptable tradeoff. I MUCH prefer a small silent flame burning all the time to a huge noisy burst of super hot flame now and then, especially for a space heater.

The hope is to be able to increase the efficiency of this type of burner, this will reduce the smoke, increase the amount of heat produced, and still keep the simplicity and off-grid/power outage capability.

I had not seen the double walled bowls, I will check into these.

johno -- Good to know that blue flames are possible if the bowl is hot enough, blue flames with yellow tips would be VERY acceptable and is the goal of these burner experiments.

jeepin -- Air tube -- The top burner support plate is not solid, it has a 2 inch diameter hole in it's center, as does the lower burner support can.

This picture shows a top view of the burner support plate.

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this is looking down inside the lower burner support can that has been drilled for both the internal and external air inputs.

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This is how they fit together.

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Thanks Tim. That's how I figured it was.. but one should neva assume.

Keep us posted. Realy like what your doing.

would be intresting to set this type of heater up inside a huge ceramic pot inverted.

See my new thread for info on this outside the POT thinking.

Tim, I'm with you all the way. I have not used a drop of HHO for heat in the past 3 winters, but my electricity usage goes up by 3X (not cheap) when the siphon burner is running on 100% wvo. If power goes out, I have no heat. Not so with the vaporizing burner.

Here's what the double wall bowl looks like.

quote:

I think the smoke tester is a bit overkill for now, I admit these vaporizing-type drip burners do put out a visable bit of smoke, a lot more than any pressure/syphon burner, but for me the simplicity and silent operation is an acceptable tradeoff. I MUCH prefer a small silent flame burning all the time to a huge noisy burst of super hot flame now and then, especially for a space heater.

The hope is to be able to increase the efficiency of this type of burner, this will reduce the smoke, increase the amount of heat produced, and still keep the simplicity and off-grid/power outage capability.

I had not seen the double walled bowls, I will check into these.

I will watch for the double bowls, haven't seen them anywhere locally.

I made up something sorta similar to try. This is a combination of harry3's small center cup and a double walled insulated bowl. I cut the bottom 1/2 inch off of a one pint SS dog bowl, used three 4-40 X 3/8 screws for legs, and three 4-40 X 9/16 screws to keep it located in the center of the bottom of the quart burner bowl. the SS material is only 12/1000 thick so should heat up fast, and the screws should isolate it from the cooler bottom and side of the quart bowl. This may let me go back to the external-air-only lower burner can, don't know yet, haven't started testing this yet.

I also made up a new bowl with 42 1/8 inch holes closer to the bottom of the bowl. The holes are 1 inch up from the bottom, this puts them about an 1/8 inch above the top of the new 1/2 inch tall burner tray insert, weel see?

I did a bit more detailed testing of the external air input damper position. The burner assembly tested was with both the internal and external air bottom can. Unfortunatly, with this internal/external lower burner can it looks like any amount of cool external air actually cools the burner tank even though it also allows a more efficient burn by adding the finger flames. With the damper completely closed there were no flames from the burner bowl air holes and the hottest point on the burner tank was 358 deg f, I opened the lower air damper until I got finger flames, then opened it more til the length of the flames did not get any longer, the damper was about 1/3 open. The tank temp dropped a couple degrees with this setting, not really enough to be a problem but when I opened the damper completely the tank temp dropped by 10 degrees even though the finger flames did not change. I assume the extra cool air is passing out of the holes in the side of the lower burner can and cooling the hot gasses inside the stove?

This is one reason for the extra burner tray insert idea, if this temp isolated tray stays hot enough to efficiently vaporize oil I hope to be able to go back to the lower burner can without the side holes, this would also put cooler oxygen rich outside air through the burner bowl side holes.

Will have to burn this a while with this added small tray before I know how difficult it will be to claen it.

This pic shows the source of the tray.

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