I. Frazier Bard

I have been experimenting on this line for the past three years. When I first took this subject up I was told by all the experts I asked for information on the subject, that it could not be done on account of the kerosene cracking under the influence of heat and clogging the passages with carbon, and also causing a smoky flame. They all said that the only practical method was that based on the spray or atomizing principle, either by pressure from the boiler or by compressed air. One of the engineers of the Westinghouse Air Brake Co., who was familiar with the attempts to burn oil in the locomotive fireboxes of several of the Southwestern railroads, told me that they had not been able to overcome these three objections - smoke, carbonization at the tip of the jet, and a loud, disagreeable, roaring noise.

I have already had some experience with jets of this type, and while I never had any trouble with carbonizing or smoke, I had never been able to suppress the roaring, and this alone made this form of burner useless on an automobile, as you could hear the burner for a quarter of a mile. Besides, it required either compressed air or steam to atomize the oil. Compressed air gives a better fire, but requires a constantly working pump to keep up the pressure in a supply tank, which should be heated by exhaust steam from the engine. Steam, while not giving quite as clean a fire, is much simpler to apply, only needing a pipe and valve from the boiler; but, on the other hand, to start the fire under a cold boiler requires air pressure to be pumped into the burner by hand until the fire has raised 15 or 20 pounds of steam. The best system of controlling the fire is to have the automatic regulator control the steam or air supply, and to supply the oil from a float-feed chamber, which would keep the oil supply level of the atomizer. I finally abandoned the atomizer principle, on account of the objection noted above, and turned to the Bunsen-burner principle.

1 started out with a burner of standard design - i. e., having air flues through the body of the burner. I soon found out that, except when the fire was burning very low, the pressure in the firebox was above atmospheric pressure, which caused a slight back pressure down the draught tubes in the burner. Evidently, under these conditions the tubes were useless for the purpose they were put there, and, if anything, they allowed the fire to down flash and retard the draught through the boiler rather than the reverse. I put a solid plate under the burner, practically closing the holes airtight, and the fire drew up into the boiler flues better, and gave no indication of smoke or lack of air. From this I deduced the first requirements of a satis-factory burner - viz.: that the proper amount of air for perfect combustion should be mixed with the jet of gas in the interior of the burner, and then driven by the pressure right through the firebox and up through the boiler flues. The burner being solid and the fire-box airtight, and there being a slight pressure above atmosphere in the combustion space, the result is a forced draft, and there can be no such thing as back draught, even if the wind should blow straight down the stack.

I now found that my vaporizer was not making an invisible gas, but a misty sort of steam when the burner was on full, but when throttled down about one-half it was invisible, until the automatic valve shut down to its lowest limit, when the vapor again became visible. The vaporizer plainly was not heating the oil hot enough to make a superheated vapor, first when the valve was supplying fuel to the full limit of the nozzle, and secondly, when the pressure in the burner dropped and allowed the fire to drop down under the vaporizer. I now found that the jet and cooler parts of my vaporizer began to clog with carbon; but the hottest parts showed no signs of deposit. From this I argued that the vaporizer must be red-hot all the time, and not allowed to flood into a partly-cooled vaporizer to recondense the vapor and deposit the carbon. 1 had now found requirement number two.

As my burner could not very well be adapted to an inclosed pilot light to keep a continuous heat on the vaporizer, I began looking for a burner which had a pilot light built into the body of the burner. I found a burner on the market which seemed to embody both my requirements. I fitted one to my car, and with it I fitted an automomatic regulator which would control the oil supply before it reached the burner and cut it off entirely when the steam pressure rose so the predetermined point, leaving the pilot to keep the vaporizer hot. I soon found that increasing the oil supply up to a certain point would increase the fire correspondingly; but beyond that point the vaporizing tube would seem to be unable to take care of the oil, and would flood just like a flash boiler when more water is supplied than the fire can evaporate. I remedied this by increasing the length of the vaporizer coil, which consisted of a piece of seamless steel tube of 1 1/4 in. pipe size.

The burner has been in use since August, 1903, and has driven my car upwards of 4000 miles. The vaporizer has never shown the least sign of carbon deposit, and the gauze strainer in the tip of the jet has only been examined three or four times, and each time only a few pieces of scale from the inside of the tube were found to have lodged in it. This, to me, is absolute proof that coal oil will not deposit any carbon when vaporized in a red-hot tube, and not allowed to cool or recondense before it is delivered to the burner. The burner itself shows no signs of carbon and burns a perfectly blue flame with never a sign of smoke. This method of burning the fuel is practically the same as in an internal-combustion engine, as after they have introduced the proper mixture of air and fuel, it is not considered necessary to have any additional valves for introducing more air during the combustion stroke, so why should there be any additional air introduced into the firebox under a boiler if there is already the proper proportion mixed with the fuel before it issues from the burner? This proportion is easy to obtain by simply varying the distance between the jet and the mixing-tube, and this proportion will remain nearly constant, automatically, as the airfeed will vary with the velocity of the jet of vapor. The fact that you have a combustion mixture in the burner would at first sight promise lots of trouble from back-firing into the interior of the burner; but, as a matter of fact, this never happened to me but once, and then was caused by the door in the casing being left open and the flame flaring out and igniting the gas at the jet.

To sum up, the requirements of a kerosene burner are:

1. No air supply to flame, except the proper proportion for complete combustion, which shall be intimately mixed with the vapor before ignition. This means a closed firebox.

2. All regulation of fuel to take place before vaporization. This means no cracked oil or condensed vapor in tubes, and hence no deposit of carbon.

3. Ample vaporizing coil kept at a cherry-red heat. This means perfectly dry vapor, no matter how hard the burner is forced by high pressure on fuel.

A burner which fulfils the above conditions will give satisfactory results and vaporize and burn kerosene oil for an indefinite period without any of the troubles which every one seems to think are inseparable from using kerosene. The above is not a "theoretical dream, "but an actual demonstrated fact, and some day will put the steamer where it belongs, as the finest touring machine to be had. - Horseless Age.