001 Waste Oil Heater

[Laylow]

I have poked around on this website off and on over the past couple of years and have just now decided to start utilizing it.  I have so many questions about the different projects that I work on that it seems to overwhelming to even start asking them.  So now I am just going to start posting comments about what I am doing and maybe I'll be able to glean what I need to from others.

The project I am currently working on is a waste oil heater based on the original MEN design.  Thanks to everyone that has ever published any of their experience with building this and similar heaters/burners.  I have read it all.  Unfortunately, there seem to be no authorities on the subject and there is very little written about the theories behind the various designs.  I can only speculate.

My current design differs from the MEN design and others in the following ways:

Heater is located in a 6'x6'x7' enclosure outside of the house.

A blower for combustion air is used but as a draw through on the exhaust side.

Supply air runs inside the exhaust air duct so there is only one 6" hole in the top.

Cone is fixed and does not adjust up and down.

Burner support has adjustable height.

Burner assembly can be removed without tools.

Fuel controls will be much more complex when I get to them.

I am very lucky to have my little enclosure.  It is made of dual wall steel pannels with 2" of insulation in between.  The company I work for often has HVAC related items that eventually find their way in the dumpster or at my house.  The heater will use 100% outside air for combustion and another set of fans to move the hot air from my enclosure to the crawlspace of my house.  My original plan for heating my house was a radiant floor system, then I discovered that a conditioned crawlspace is not only going to be more efficient but it will also be a whole lot cheaper to install and whole lot easier.  I will eventually post all of my work on the radiant floor heat system if I can still find it.  For now I am just pointing out that a conditioned crawl provides the same type of radiant heat with numerous advantages.  All that is required for a conditioned crawl is to cover the ground with 6 mil plastic and insulate all of the crawlspace walls.  After that, any source of heat you put down there will radiate up through the floor.  This is not a "crawl plenum!"  Crawl plenum = bad idea.  Much more on this later; I was just explaining what the enclosure was all about.

It appears that most DIY waste oil burners require some forced combustion air to burn clean.  My reason for going with a draw through blower is to avoid any possibility of combustion fumes leaking out of the heater.  The enclosure will be under positive pressure and the heater will be under negative pressure.  Of course, the challenge I will face is to see whether or not I will be able to cool the exhaust gasses enough before it gets to the blower.

The supply air duct is 4" vent pipe coming from outside.  It will pass through a 6" to 4" reducer as a way to get inside the 6" exhaust duct.  The 6" duct will run to the trunk of a T and the 4" duct will turn 90° inside the T and down into the heater.  The other arm of the T will also be fitted with a 6" to 4" reducer providing the exhaust gasses a route to exit.  Their will be some heat exchange between the supply and exhaust combustion air which will help cool down the exhaust gasses for the blower.  Hopefully, the supply combustion air will warm up enough that it doesn't cool down the dripping oil.  The supply air fan for the enclosure will be pointed directly at the duct carrying the exhaust gasses.  I hope that the exhaust duct is not something that will have to be cleaned very often.

I did not want to fool with adjusting the height of the cone every time that I needed to clean the burner assembly.  Thin sheet metal parts just aren't made to withstand repeated mechanical manipulation.  I designed an adjustable base for the burner assembly instead.  I used two brake drums, one sitting on top of the other for height.  No modifications were made to the lower brake drum.  I welded a sheave with a 3/4" bore to the top of the other brake drum.  I welded a 3/4" nut to the top of the sheave using a piece of 3/4" allthread for a centering guide.  The allthread can now be screwed in and out or up and down through the brake drums.  I welded another sheave with a 3/4" bore to the top of the allthread to place the burner assembly on.  I drilled two 1/4" holes into the outer perimeter of the sheave and welded some pins into it.  The pins fit inside two holes drilled into the bottom of the frying pan of the burner assembly.  Now, if I want to remove the burner assembly, I just spin the burner down till it clears the cone and then lift it off the pins.  Originally, my plans involved trying to use pipe flanges with threaded rod.  It almost works but pipe fittings tend to be cast and it is almost impossible to find a straight one.

I must admit that my plans for oil delivery are still kind of foggy but I intend to have just about every safety that I can think of.  It is very hard to find parts that say they are compatible with oil; motor or veggie.  Actually, from what I've seen, valve seals are more likely to withstand motor oil than WVO.  I have a solenoid valve that I hope will work.  I also have thermostats, air pressure switches, and limiting valves.  Should any number of conditions fail to exist, the solenoid will lose power and shut off.  I am debating on whether or not to reduce down to 1/4 tubing.  I will probably just use 3/8" pipe and let the throttling valve do it's job.  Although it shouldn't be necessary, I will place a second "limiting valve" closer to the end of the line that will be adjusted for highest allowable flow at hot oil temperature.  If it is too restrictive at cold temperatures I will just remove it.  Other elements that will be added are a heating element inside the drum in case there is need for a cold start, a viewable sediment and settling trap, and a valved port so that I can pump fresh oil back up to the delivery tank.

A note on throttling valves:  The valve I am referring to is like a combination ball valve and needle valve.  The ball valve is used to shut it off and inside of that is the needle valve which can be adjusted to limit how much can flow through the port.

I have finally started putting my system together and I am more than halfway through.  From this point on I will try to document my work as it goes and if I have the time I will fill in the parts that I've already done.

[buddy448]

I use an old Stewart Warner electric fuel pump which I hooked up to an aftermarket electronic pulse windshield wiper control to feed anything from used motor oil to contaminated diesel fuel into my home made waste oil burner.  When the pulse unit cycles 'on',  it feeds the fuel pump and draws the plunger/piston to one end,  causing oil to be drawn into the housing.  When the pulse unit cycles 'off',  the fuel pump plunger/piston is released and oil is pumped out.  Increasing pulse rate increases oil volume pumped and,  therefore,  heat output.  The oil is fed into the combustion chamber by 1/8" brake line.  Safeties are in the form of a pair of hot water heater control switches connected in series inline with the fuel pump.  The advantage of using the timed pulse system is that the viscosity changes of the fuel due to temperature and composition doesn't affect the amount of fuel pumped. You simply turn up the pulse rate for more heat. I run a 5/16 steel inlet line of which about two feet run by the firepot for some heating up to make pumping easier in cold weather.  Hope this is of help...

Regards,

Andy

[Laylow]

Thanks for the input.  I would love to hear more about your heater.  What burner design are you using?  I am really hoping to use WVO but I understand that it might be a little trickier than motor oil.  I think I've strayed away from using a pump because I immediately start thinking about an atomized system but I don't see why I can't just a pump with the drip design.  I like the windshield wiper controller setup; it's probably a lot simpler and more elegant than trying to make your own circuit.  Electronic circuits always wind up being more complicated than I think they are going to be.  

At this point I really just want to keep things simple.  Things are taking long enough as it is.  I think that once I get things running my next area of focus will be in controls.  As I have things in my head right now, the only controls I have are either on or off.  With a variable speed pump I might be able to get specific furnace temperatures.  It will be interesting to find out what the minimum amount of oil is that the burner needs to stay lit.  Once I figure that out I'll probably start toying with different oil delivery methods.

Please, I would love more info on your burner.  Pictures would be great too.  I know that there are others on this forum that have a lot of experience building waste oil heaters.  I've learned quite a bit from them.  I've found forums here and there with some interesting posts on waste oil heaters but I've never found any of them to be the definitive waste oil heater forum.  So far I think that this forum has the best potential so I am investing in this one.  I hope that the rest of the oil burners will come out of the wood work this year and start using this forum too.

[Laylow]

I finally broke down and bought one of those duct crimping tools for $20.  I've never wanted to have to buy one of these things since I will rarely ever use it.  It didn't take long for me to change my mind though.  It might be years before I ever use it again but it allowed me to make some joints that would have been very difficult or expensive otherwise.

I am always hanging around the hardware store looking for items that will serve purposes other than what they were intended.  This time it is something that I can use as 2" duct.  My exhaust blower has a 2" outlet and the smallest duct available is 3".  I was able to find a 6' piece of 2-3/8" fence post that I think will work.  I thought about using conduit but I didn't want to buy 20' of it.  I'll see if it fits when I get home tonight.  I think the actual OD of my blower is 2-5/32" and the ID of the fence post is 2-1/4" so maybe this will be a good fit.

Here are some pics of the enclosure and the circulating fans.

And here are some pics that show the combustion supply and exhaust ducts being assembled.

And here is the adjustable burner stand.

[nothing to lose]

Hmm, I like it, but I don't understand it at all.

Looking at the pics, It looks like one blower sucks outside air and blows into the room. Another blower sucks room air and blows somewhere. Both blowers on one motor I get. Then the oil furnace duct appears to just blow open into that room? I know I am missing something here or the way I am looking at this you would be drawing outside air, heatng it, adding burnt oil fumes and blowing all of it to the house, and I know that is not correct, what did I miss?

I do like that setup, very nice and cleanly built. I just don't see how it works really. Though I think I know what most the parts are. Copper bottom frying pan I like

I think that's what it is.

[Laylow]

Hi nothing to lose,

The fans that you see in  the picture are for circulating air in the enclosure only.  The fan that is blowing in is pointed at the combustion exhaust duct in an attempt to cool it off before it reaches the combustion exhaust fan which is not shown yet.  The duct for the heater itself is not finished yet.  The upper duct, which is the combustion exhaust, will run into a small 120W blower.  Then the blower will need the 2" elbow that I was talking about so that it can run to the outside through the wall.  The lower duct, which is the combustion supply duct, just goes straight through the wall.  This is actually already done but I don't have a picture yet.

The design is really no different than the one's in the MEN article or what they've built at journeytoforever.com but it has been modified to work in an outdoor enclosure.

After this is complete I may start toying with other designs like robotmaker's.  I think that robotmaker's design could be easily adapted to use water atomization.  Someone else mentioned on this forum the idea of using a wick.  I wonder if that is really the way to go.  Maybe a kerosene heater wick with a "dog waterer" oil delivery system and a fan to keep things hot.

I don't really know if the MEN design is a good one or not.  After they abondoned it there hasn't been any support.  I have no idea why I'm using a cast iron frying pan, or what the holes are for, or how big and how many there should be, or if they should line up with the holes in the plate.  What was the guy thinking?  All anybody knows is that it worked.  I went with the MEN design because journeytoforever said that they had trouble getting robotmaker's design to work with WVO.  I should probably go through robotmakers stuff again and see what he says about it.

 

[Laylow]

I spent most of Tuesday night walking around the hardware store.  I changed my mind on the combustion exhaust elbow again and bought a 2" emt elbow and coupler.  I just didn't feel like welding on thin galvanized fence post.  I should probably learn how to braze better.  I also spent about $50 in pipe fittings.  I couldn't find any fittings over 1-1/2" that weren't hot dipped galvanized so I guess I'm stuck with it.  Hopefully, using enough teflon pipe dope will keep it from seizing up on me.

I also thought of a good way to connect my 4" duct to the inlet of my exhaust blower.  I will take a 4" end cap and drill a 2" hole in it, then I will screw it to the fan from the inside and push the whole thing together on to the end of the duct.  It should work nicely.

Last night was a bust, as usual.

Tonight I will try to get the plumbing done and start on the electric panel.  I really haven't come up with anything special for controls.

I need to find out what the minimum amount of oil needed for continued combustion is if I want to try to modulate the oil flow.  If I find that out, I can probably use the solenoid valve to control the burner temperature.  I also wish that I had a way to sense the flame.  That is the real safety factor that I am lacking.  I have access to plenty of flame rod sensors but I don't think they would work in this application.  Actually, I can't think of any good system for sensing flame in this application.  An optical sensor needs a direct line of site and a steady flame.  I assume that the Infrared sensors check for a core temperature which might be mislead by the heat radiating from the cast iron.  I don't know, IR probably has the most promise.  A slight delay before shutdown would be okay and maybe even beneficial for preventing false negatives.  Too bad I don't have one.

I WILL TRADE A HONEYWELL FLAME SENSOR/IGNITOR TO ANYONE THAT HAS AN IR FLAME SENSOR!

I should also crack open a smoke detector and see if I can use it as a relay.  If I had a flaming oil spill (unlikely) I could use it to shut down the fans.

It'll be another cold one at my house tonight.  Brrr.  Should've started last spring.

[nothing to lose]

Ok, I understand more about the airflow then, I did not visualize it correctly without the other duct work.

I liked Mother Earth News long ago, have alot of old copies of it still. Haven't seen any newer ones for awhile. I think I have Issue #2 I got somewhere. For awhile they got to be to many adds not enough good stuff, not sure what years those were but I heard they got better again after that. I just gave up on them myself, seemed like they got into too much of trying to sell plans and such, where as they started out providing more usable information right in the articals. Maybe just my perspective of it??

Problem I see with MEN  is that people take them too serious at times and don't look for ways to make things better. They just say oh Men did it but cost them $10,000 in horse hair filters to run a gasifier truck cross country. Hmm, did it? Was it needed?

I got that from several people with tons of scrap wood and stationary gas engines. Because MEN supposedly throwed money away foolishly on a project lots of people now think gasifiers would be too costly to run. For a stationary engine there are tons of ways to cool and filter the gas cheaply, but they read MEN and let the wood rot instead of using it and try to tell me why it won't work

Those Mento wheels may never work anyway, but I can look at the pics of the one MEN built for a ton of money and see several reasons right off why I would not even expect thiers to work. They had the money to waste and they did.

Sorry to hear they abandoned the oil furnace your building also. I geuss that's strike 3 against them in my book, or is it 5 or 6 now??

Looks like your doing a great job of building it, but I can see how it would be nice to know what and why about the holes and such.\

" Someone else mentioned on this forum the idea of using a wick.  I wonder if that is really the way to go.  Maybe a kerosene heater wick with a "dog waterer" oil delivery system and a fan to keep things hot."

You do know a normal candle wick held floating in vegtable oil will burn like a candle right. They make little floaty things you can stick a candle wick into and you put water in a container then veggie oil on top the water. The floaty floats on the oil, the wick sucks it up and burns, when the oil is used up the wick picks up water and goes out. In case the container is spilled it is mostly water so it should go out as a safety also. They make good ones and cheapy ones like that.

 Now how you would want to do it for heating may be something else, but the wicks do work with oil. The warmer the oil near the wick the thinner it is and the better it works, to a point, course you don't want it really hot nor ignite the oil itself when using wicks. I would think the wick from a kerosene lamp would work the same way, maybe better not sure, and be a larger hotter fire. Kerosene heater wick then I bet would work well also. As an oil feed thought, for about $6 you can get a shutoff float valve from a feed store that connect to a water hose. I used them to water animals when I had some. It works like any other float system like a carburator or toilet tank. When the fluid level raises to a preset level the float shuts off the hose. The plastic $6 one worked well for a water hose with a pressure on it, it should work just fine for a gravity feed system with oil also I would think. So if you had an Oil tank nearby and need a pool of oil to feed a wick system mounting a shutoff  float in the container for the wicks oil and running a water hose to the storge tank should keep things full to your prefered level. Since it would be gravity feed you would need the blk of the storage oil above the level of your oil pot for the wick of course.

This is something I should try myself but I have enough projects not done yet, don't need to start another! I have the float, old hot water tanks, and about 150gal used cooking oil from a friends restaraunt (never got a diesel engine), extra water hose too.

 

[nickelbender]

I found a group at Yahoo that convert oil furnace burners to wvo.

http://groups.yahoo.com/group/altfuelfurnace/

Perhaps this is something of use too you.

I also read the MEN waste oil burner article and found it worth the read and printed it should I ever decide to use the low tech aproach.

[Laylow]

I've been there but I can't be in their club unless I own a commercial oil heater.  If I had one I probably would've been putting all kinds of oil in it from the get go.

There is another site that I can't find again to save my life.  I thought it was at the end of a thread on this forum.  It was a guy from some place like Australia or New Zealand or something.  He built a waste oil heater that seemed to be of his own design.  The part that caught my attention was that he said the oil dripped into ash or sand or something where the heavy metals would most likely collect.  Then the oil did a kind of pyrolosis burn.  Anyone remember seeing this?

[ghurd]

In WWII they used a drip burner. It would burn about anything acording to an old timer who used them, gas, diesel, oil...  Might be worth a google.

G-

[Laylow]

Project remains incomplete at this time.  Had some very weird things happen and no time to investigate.  Smoke did leak out through the door even with draw through design.  Probably because pressure isn't equalized throughout the enclosure.  I had it set up so that I could watch the oil level.  When I got down to the last quart of oil I could see how fast it was being used.  The gauge was 1" clear vinyl tube.  I would open the valve and see oil dripping through pretty fast.  It was difficult to get the burner assembly up to operating temperature.  The oil level is dropping so fast that I figure I've only got a few minutes left but as soom as the fire really started going the oil level would rise back up!  A lot!  Like 6 inches and fast.  It was cold, I was tired, i just stopped caring.  I don't know what was going on and finding out wasn't going to be easy.  i was overwhelmed with possibilities.

Other factors that put me off the project were not having enough time with my family and oil collecting was turning into a complicated affair.

Oil Collecting:

If the restaurant pumps their oil with a hose 55 gallon drums work great.

If they pour into the container by hand you have to design a container that has a rain-tight lid and a wide mouth.

Oil may have to be heated to pump into transfer containers.  Using a 600W DC water heater element  turned out to be futile on Vegetable shortening.  It might work great on regular cooking oil.

12VDC 10A pump wasn't exactly doing 6GPM at the amount of head that I had (a shorter hose might fix that, just haven't tried).

Anyway, I don't really want to give up on it but I'm not sure that it is worth pursuing.  The gasifier furnace seems like a better bet and the fuel is easier to come by and transport (or buy).