"Dirty Deeds Done Dirt Cheap" 
Home Made Waste Oil Heater. (Probably my most sucessful project)
It has been said that, "You can take the man out of the Boiler Room, but you can't take the Boiler Room out of the man". My past experience with steam, it's generation and uses has given me a fascination with heat and energy that almost borders on an obsession. Plus the fact that I'm naturally "miserable" when there is the possibility of getting something for nothing.
Sometime circa 1998,  several mates and I were discussing the feasibility of a home handyman being able to develop a heater capable of burning waste oil (sump oil) without smoke or smell. We were aware that there are several commercial models of heater available, but all of these are both expensive and require the use of electric pumps and fans for combustion. I wanted to avoid the use of electricity, so that my heater could go on working in the event of a blackout. After a lot of discussion I could not convince my detractors that it was possible, so being a determined type of bloke, I set out to prove my theory that any carbonaceous fuel will burn properly so long as it has enough heat and air, with the air having to be properly mixed with the fuel. All I had to do was work out how to achieve it.
The first working prototype took about three months to build, as firstly I had to decide on the method of combustion and then work out what materials I had at hand to make the parts out of.
To ensure that it would withstand the heat generated I decided to use cast iron and cast steel wherever possible and found that this was easily and cheaply found in the junk heap of a local trucking company. Worn out brake drums were found that fitted together with an almost airtight seal, and an old clutch plate and cylinder liner just about completed my list of parts. All that remained was a pan in which to burn the oil and a cover for it, for this I used an old cast iron camp oven and a spring steel disc plough shear. There was not a lot of thought needed to put these things together in such a way as to give me the type of combustion that I wanted and also make it reasonably easy to assemble and pull apart for maintenance, so I just built it "by the seat of my pants".
The resulting "contraption" worked almost faultlessly right from the first test burn, with only a little bit of experimentation needed to decide the best size, number and location for the air inlet holes in the secondary flame tube. I ended up making up an extension for the drill so that I could actually drill the holes in the tube while it was burning, any mistakes were simply welded over with a nickel electrode, this ended up making the tube rather untidy looking, so once it had been determined what was needed I simply counted the holes and made a new tube with the holes drilled in a neat diagonal pattern.
After this experimental stage I wanted to see if it worked in an enclosed environment, so much to the dismay of my wife, I removed our slow combustion heater from the living room and attached the oil heater to the existing flue, then drilled a 15mm hole in the wall, through which I then plumbed the oil line which was temporarily attached to a tank holding several gallons of waste oil outside.
On the night that I got everything set up, it was quite cold and miserable by South Australian standards with an outside temperature around 4 to 6 degrees celsius. After a warmup period of about 30 minutes the heater started to radiate a considerable amount of heat so the oil valve was closed slightly and I sat back to see what would happen. At this time I was still not aware of all of the burning characteristics of the heater which when being tested outside seemed to be quite docile in it's performance. Perhaps it was just that the build up of heat was much more apparent inside, perhaps it was the extra length of flue on the chimney, but on this night I discovered why it is not wise to let too much oil accumulate in the oil pan, It just got hotter and hotter, I turned off the oil supply completely but it continued to burn the oil that had accumulated in the pan, by this time the flame tube was glowing a rosy red along with the bottom 10 centimetres of the heater body, the pyrometer fitted to read the exhaust gas temperature was fast approaching 1100 degrees. At about this time I had vivid imaginings of what the operators of the Chernobyl reactor must have felt like as it ran out of control, things were getting desperate. Shirley, my wife was opening the windows and doors in an effort to reduce the heat buildup in the living room  and kitchen area, even I was worried to the point where I used a broom to push open the manhole access into the roof in a last ditch attempt to get rid of the heat. After a few minutes the the residual oil burned off and the heat started to subside, and it was only then that I noticed that the radiant heat from the now glowing heater had "crazy cracked" the plaster on the stone wall 50 cm behind it and melted the coaxial cable going to the TV,.... it had been a near thing.
The next trial inside was conducted on the following night after having made a few adjustments to lessen the possibility of a repeat of the previous night. I had covered several rows of secondary air inlet holes, and only opened the oil enough to keep the heat well under control. Meanwhile, Shirl stood 10 metres away at the far end of the kitchen wearing her best "You'll never learn" expression and looking like she was ready to bolt out of the door at the first sign of trouble. It was a slower start taking about 40 minutes to get up to the desired temperature resulting in almost a perfect run, although I found that I still needed to close off a few more rows of secondary air inlet holes to enable it to burn cleanly at lower heat.
The heater has continued to work virtually without any problems ever since. Even Shirl' has come to accept it, realising how much time, effort and money it saves us every winter, not to mention the trail of wood chips and dirt tracked inside every night. To ensure clean burning the ash needs to be chipped out of the pan almost daily, I say "almost" as it will burn quite well for two days, maybe three without smoking, but the ash becomes thicker and forms an insulating layer which allows a sticky bitumen like residue to form in the bottom of the pan under the ash crust. Daily cleaning keeps the ash layer thin which allows the radiant heat to vapourise the tarry residue whereupon it is burnt prior to the ash being removed.
I do use some electricity, however should it fail I have enough fuel in the ready use tank to last over two weeks of cold weather. A small electric gear pump is operated for three minutes daily by a time switch, this transfers about 35 litres of oil to a 400lt overhead tank, this is well in excess of my normal daily requirements, any overflow is piped back into the main storage tank. The oil then gravitates through a 20 mm polypropylene underground pipe to the house  about 40 metres away, in this line I have fitted a final strainer/filter and a gravity water separator (Seen at Right), to remove any traces of water or grit from the oil before it is burnt. In five years I have cleaned the filter once and drained off about a cup of water. All of my oil passes through a primary strainer and water separator before going into the main storage tank. The piping within the house is all 12mm hard drawn copper tube with silver soldered joints to eliminate any possibility of leakage, there are six isolation valves between the gravity tank and the back of the heater to allow for the oil to be switched off in an emergency or to allow maintenance on the filter and separator.
I have often thought about connecting this heater to my hot water system, however because of the distances involved I have decided that it would not be practical, and I guess that a turbo-alternator is out of the question???
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