I posted in the military heater thread about using one of those tent heaters in the bottom of a 40 gal tank water heater.
I had a friend cut a hole in the bottom and welded up some tabs to hold the burner in there.
I did a quick test and used diesel to fire it off and other than everything seeming to work ok. What color should the flames be they looked more orange than yellow I did not have a flue on top of the water heater but it seemed to burn clean after it heated up.
I has been mentioned that controlling the heat will be a problem I will put in a temp guage on the tank and set it to a low setting like 1 or 2 and see what temp it stays at. I have been thinking of implementing some kind of car thermostat and radiator to control the temp but perhaps at it's lowest setting it will be ok.
Flame color -- From reading through the "military heater" discussion, most seem to say they get yellow flames til the burner is up to temps, then they get blue flames? The amount of air through the burner controls the flame color, you will need to add several feet of flue pipe to the top of the water heater to insure you get a good draft, without the flue draft you likely won't get a clean burn from the burner or transfer heat into the water efficiently. The upper flame section of the burner also needs to be enclosed so all the draft air is drawn in through the holes in the lower section of the burner rather than across the top of the flames.
I don't have any hands-on experiance with one of these burners but my SS dog bowl burner won't yet make blue flames burning straight veg, trying to improve this all the time (HERE), blue flames would be the most desireable but it may take a bit of forced air to the burner to accomplish it.
There is no simple way to control the temp of this type burner using the float carburetor that comes with it but if you drip-feed the fuel into the burner using some type of electric motor powered fuel metering pump, or an electric solenoid valved drip, you can electronically control the amount of fuel by using a custom designed thermostat to control the speed of the fuel pump motor or the solenoid valve pulses. The burner would still burn all the time but the amount of fuel being fed into it would control the average temp coming from the heater.
Since the burner is always burning you may need to add a bypass radiator water cooling system to insure that you did not boil the water, automatically turn on a small water pump if the water temp gets above some temperature.
Yeah I figured that I would have to get it better sealed up. I am going to the only fireplace place here later this week to see if they have any of that stuff you put aroung the fireplace door that I could use to seal up around the military heater to the water heater.
For the flue I hope that just a section of 5' pipe will work if not then maybe some kind of blower in the flue to help perhaps.
For the thermostat I wonder what the innards of the propane one was like if i could use that in some way to meter the additional fuel in.
Thank you again for your insight.
Ok just a quick note not sure if it is any good news or not.
Got a bit of blue~ish flames not a steady roaring kind of flame but it had a nice flame.
Anyway using diesel on the #4 setting I heated up the 40 gallon water heater up to 120f in about 80 minutes.
I will continue sealing it up better.
Used a 80%/20% WVO/RUG blend last nite got a decent purple~ish flame I still need to add a 4-5' section of pipe on the top that should help a bit.
Water temp goes from ~85f to around ~110f in about 45mins. Seems it takes awhile till everything gets up to temp in the pot it seems to run the best right about the time I turn everything off after running for about 3 hours.
On this last run it was consuming a little over 1 liter an hour on the #7 setting.
Be VERY cautious using any blend with RUG in an enclosed space. The volatile components can evaporate out of the mix and form an explosive mixture. ANY blends containing RUG should be handled like RUG in terms of safety.
Yep everything has been done outside away from my house on a concret slab. I have only been mixing about 1 liter at a time and only that for testing.
I will test tonite with some wvo/diesel blend.
Blending 70% WVO and 30% Diesel seems to burn fine.
I was thinking about trying to seal up the lower portion of the heater and use a small 12v fan to put some air into the bottom section think it would make it work better?
A fan might help? There is a commercial manufacturer of drip fed oil space heaters that use a similar burn pot as the military heater. This links to a Thermobile.com web page for there portable heaters, download the manual for the "AT" model heater and it has a drawing showing a small fan feeding air to thee outside of the burner.
Thank you for the information I got a friend to weld together a sleeve and bottom I will have him put in a hole to feed the oil to the pot and have that sealed up as well and another hole put in to add the additional air should I have the hole put in the same way as the turk burners to get a swirl effect?
Adding a fan to supply more air to the vapour pot burner will not help you in any way. It will only serve to create a very yellow, sooty flame. The tent heater was designed to work at atmospheric pressure. It is self regulating in the amount of air it takes into the combustion chamber, this is governed by flue temp./flue draught. Also critical to the efficient operation of these burners are, 1) flue diameter (4"), 2) air tight combustion chamber other than that around the air inlet holes in the pot its-self 3) flue length and an efficient flue terminal.
You will also find that a flue balancer could (will) be needed to ensure the correct vacuum under correct flue opperation conditions in high winds. There is a tendency in strong/high wind conditions for the flame to be pulled away from the wall of the of the pot causing large fluctuations in working temperature. I have trialed the tent heater over a period of time and experimented with various blends, your 30/70 blend is a good place to start, to get a better flame and see the center post of the pot burner fully alight, try a 40/60 blend. Its all down to viscosity. Best of luck with your trials and remember, Ockhams Razor rules apply.
Well my inital succes have prompted my friend to also try. So he got his pot burner(s) in the mail the other week and well here I am back at it.
Espana1 what would you recommend for flue diameter and length for the heater. Also do you recommend running the blended fuel with or without the pilot ring?
Sorry for the delay, its fiesta time here, just come home to catch a few zzzzzzz and then back again! (and this is 4 in the afternoon)
1) Flue dia. --- 4''
2) Flue length -- The one I have here works well on 2 metre overall length but you can go higher, perhaps 3,4 mtr. but beware, too high creates excessive chimney draught leading to low flame (excessive air intake cools the pot hence low flame) and noisy operation.
3) Found it better to run with ring in position.
Best of luck, keep us informed of progress.
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