Siphon nozzle for WVO woodstove drip upgrade

Space Heating with SVO WVO Vegetable Oil Biofuel.

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Siphon nozzle for WVO woodstove drip upgrade

Postby SunWizard » Sun Oct 24, 2010 10:56 am

Its that time of year again where I fire up the wood stove. This year I am going to experiment with using a siphon nozzle and air pressure. These work with low air pressure of 5- 10 psi, and low flow of .5 - 2 cfm. I like these better than a babington ball (a similar option) since the SVO can be fed with more methods: siphon, pressure, gravity, and can work over a wider range of flow rate. And I think they give the best atomization and spray pattern. These are the nozzles used in most commercial WVO and WMO (waste motor oil) burners, and are recommended by most who are converting their HHO home heating oil furnaces like a beckett. Here is a diagram:
Image
and here is a cutaway view of the nozzle:
Image

Here is a source for the nozzle for $24 in a variety of sizes for different flow rates. They also sell the 17147 adapter so it hooks up with 1/8 and 1/4 pipe threads. My house is easy to heat so I went with a small .40 size. Then I got a small and quiet Thomas 107 air compressor to pressurize it, that is a match for the airflow so that it won't be cycling on and off constantly:
Image
This is an industrial diaphragm pump which is supposed to last far longer than piston type compressors. Its similar to many air brush compressors.
I will report on how it works once I get it all hooked up. I will use this similar to how I did my Simple SVO drip into woodstove and this should give a cleaner burn. I will start the stove on wood, then once its hot, switch over to the SVO nozzle.
Last edited by SunWizard on Tue Nov 30, 2010 9:29 am, edited 1 time in total.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby SunWizard » Wed Nov 10, 2010 12:38 pm

OK I got this thing running, and it works great. It atomizes the SVO very well, and burns with no smoke and without the usual veg oil smell when you are outside and get in the exhaust stream. The air pump is very quiet and is a good match for that nozzle size. It only draws 100 watts. The fire makes more noise than the pump, the fire makes a roaring sound its so intense. Its producing more heat from about the same very low flow of SVO that I used to use with my drip burner. I can tell its going to be more than I need to heat my entire house (run < 8 hours a day) even in the coldest <0 F weather, and its burning around 0.2 - 0.3 gallons per hour.

Currently I operate it like I did my ramp burner described in another thread below, where I start up with a wood fire, which melts the totally solid hydrogenated VO in a big pot on top. Then after about 20 minutes its liquid and I open a needle valve for the SVO flow, and plug in the pump. I unscrewed and removed one of the air inlet adjusters on the woodstove, which left a 1/2" diameter center hole which is where I spray through into the firebox. The center hole is surrounded by the air intake holes which form a 2" diameter hole around the nozzle.

Its fun having the glass front on the stove to see the flame, its a nice blue cone for about 3", then yellow for a total flame of about 12". Its amazing to watch and almost burns your face its so hot. I am going to experiment to lower the roaring sound of the flame, I might try a smaller nozzle or changing the position of the nozzle and air intake. So far it seems its burning the hottest when its roaring the most.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby David » Wed Nov 10, 2010 11:23 pm

Sounds great!

I'm always on the lookout for one of those stoves or heaters with the wetback that is used to heat water.

I could run the burner at a higher rate when i'm around to heat the water and then when i go to bed, just have the hot water circulating through radiators to keep the place warm and not have the fire going at all.

You seem to be getting very good economy from this burner setup.
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Postby mike_belben » Thu Nov 11, 2010 10:38 pm

i think the roaring is usually the sound of turbulent air being sheared as its drawn into the stove intake. if you put a bellmouth having a radius of 1/2 times diameter, this should quiet down considerably.


did you have to change any configuration on your WVO feed line or just connect the gravity drip to the oil port on the nozzle?
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Postby SunWizard » Thu Nov 11, 2010 11:43 pm

mike_belben wrote:i think the roaring is usually the sound of turbulent air being sheared as its drawn into the stove intake. if you put a bellmouth having a radius of 1/2 times diameter, this should quiet down considerably.

I agree that's probably the cause, thanks for the idea.
did you have to change any configuration on your WVO feed line or just connect the gravity drip to the oil port on the nozzle?

All I changed was a slightly longer 1/4" tube for the gravity feed connected to the nozzle. I have to pre-heat the SVO longer than I did with my ramp burner, until its about 120F before it burns consistently with the cleanest blue flame.

I have run it for about 6 hours now over 2 days. One issue I have to work out is that after a few hours, the firebox cools so it isn't hot enough so the flame goes out. I think its because my stove has a large firebox 3' long x 2' wide x 2' high. I may add something like a pipe or channel to concentrate the heat. Throwing in a small piece of wood works too.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
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Postby mike_belben » Fri Nov 12, 2010 12:10 am

are you spraying into the bowl, or just open box? is there a puddle of oil burning somewhere, or does it all flash while airborn, to create a sort of roaming fireball inside?

with my current drip experiments, im finding a limbo between keeping the damper open for the draft to stay up, yet losing all the heat out the chimney, and dampering down to retain heat, but loosing the turbulence to keep the flame stoaked, and having it die out.

i think im going to machine an aluminum block to pass my oil through as a pre-heater, mounted near the smokepipe. or perhaps inside the fire chamber. then braze a threaded end to the drip tip that will accept carburetor jets (since i have tons of them) to find that sweet droplet size. then pressurize the pot to get the veggie to flow through the additional plumbing and jet restriction.
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Postby David » Fri Nov 12, 2010 4:18 am

SunWizard wrote: One issue I have to work out is that after a few hours, the firebox cools so it isn't hot enough so the flame goes out. I think its because my stove has a large firebox 3' long x 2' wide x 2' high. I may add something like a pipe or channel to concentrate the heat. Throwing in a small piece of wood works too.


Try building a 3 sided box out of bricks with one brick on the top and firing the nozzle from a distance into that.
IE, a brick at the end the of the nozzle with 2 bricks running parallel and a brick over the top of the 3.

This will help confine the heat and the flame and give the oil a hot surface to vaporize and burn on. I do this with my Tube burner and it works great.

Your basically building a big glowplug for the oil to burn against.

This will allow you to keep the burn rate down and still have the retained heat you need for combustion.

The other thing would be to open the thing up for a few minutes every couple of hours to get the heat up again. If it gets too hot inside, open the window and enjoy some fresh air.

If you want to really make the neighbors think your wealthy, crank the thing up and leave your front door open. :D
_____________________

I don't give a damn about what might or could happen until a significant group of people can tell me it HAS happened to them.
Until then, it's just more endless gloom and doom Veg folk law.
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Postby mike_belben » Fri Nov 12, 2010 6:42 am

David wrote:
If you want to really make the neighbors think your wealthy, crank the thing up and leave your front door open. :D


wealthy or section 8 :P
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Postby SunWizard » Fri Nov 12, 2010 9:41 am

mike_belben wrote:are you spraying into the bowl, or just open box? is there a puddle of oil burning somewhere, or does it all flash while airborn, to create a sort of roaming fireball inside?

Open box, with ashes on the bottom. For the first hour, there are hot coals on the bottom. Then the ashes on the bottom still glow orange.
with my current drip experiments, im finding a limbo between keeping the damper open for the draft to stay up, yet losing all the heat out the chimney, and dampering down to retain heat, but loosing the turbulence to keep the flame stoaked, and having it die out.

Yes its a real balancing act of air flow, veg rate and heat, and heat of the ramp and box.
i think im going to machine an aluminum block to pass my oil through as a pre-heater, mounted near the smokepipe. or perhaps inside the fire chamber. then braze a threaded end to the drip tip that will accept carburetor jets (since i have tons of them) to find that sweet droplet size. then pressurize the pot to get the veggie to flow through the additional plumbing and jet restriction.

Then you are getting close to my pressure nozzle design, only pressure of air is less likely to clog than pressure of SVO. The hotter the SVO the better, my pot on the stove top keeps getting hotter the longer the burn. Limited by loss to the room it tops out at around 180F.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
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Postby SunWizard » Sat Nov 13, 2010 9:30 am

I solved the issue of it slowly going out after a few hours. I tested by heating the copper SVO feed line for a few seconds with a propane torch, and it made a much larger flame. With my IR thermometer I determined its mostly the temp of the nozzle block that determines how big a flame, and it was getting too cool which lowered the flow, which lowered the flame, etc. The hotter it gets, the lower the SVO viscosity, and the bigger the flame. I shortened the 1/4 feed line for less heat loss, and I enlarged the opening in the stove so I can adjust how far the nozzle is protruding inside the firebox. This gives me a good control of the temp of it, and the size of the flame. This works much better now and I have a wide range of firing rates where it burns with a consistent flame size over hours.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1720
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby SunWizard » Tue Nov 30, 2010 9:32 am

I have burned this with good results many days now. I can adjust to a wide range of flames ranging from 1' to 3' long. Here are some pics:
Image
Image
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1720
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby SunWizard » Sat Dec 18, 2010 3:25 pm

This nozzle has been working great for a month now. With liquid room temp VO, it starts right up without preheating. I have considered adding a 3 way valve, to run on liquid WVO for startup, then switch to my solid hydrogenated SVO after its been running about 20 minutes and melted. I haven't done this since I still have lots of firewood which I use just for startup, the first 15 minutes.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1720
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

preheat or not

Postby harry3 » Thu Dec 23, 2010 9:28 am

Sun- I was wondering if the room temp vo burns clean, or after it gets preheated it does better.
I burn all liquid vo and don’t want to pre heat it if it is not necessary. This is something I my toy with this summer, my drip heater is working very good but am always after a cleaner burn.
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Re: preheat or not

Postby SunWizard » Thu Dec 23, 2010 10:28 am

harry3 wrote:Sun- I was wondering if the room temp vo burns clean, or after it gets preheated it does better.
I burn all liquid vo and don’t want to pre heat it if it is not necessary. This is something I my toy with this summer, my drip heater is working very good but am always after a cleaner burn.

Yes liquid SVO burns clean right from startup. Its a smaller flame at first which then grows as it heats up. Its amazing how much cleaner it burns than my drip burner, I will never go back. It has even cleaned out the firebox and chimney from a thick layer of soot from the past 12 years of burning wood and 2 years of dirty drip burning.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
SunWizard
Site Admin
 
Posts: 1720
Joined: Mon Dec 11, 2006 2:53 pm
Location: N. Colorado

Postby powerstroke73L » Sun Feb 06, 2011 7:57 pm

I love this idea but I don't have a convenient hole in my firebox like Sun's stove-I would consider drilling a hole through the plate around the door (I could always plug it later) though. How big of a hole would it need to be and are the threads NPT or another type? Would it work to thread the nozzle into the wall of the firebox or does it need to be further in?
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