The PRESIDENT. I now have the pleasure of introducing to you Mr. CHARLES H. FISH of Manchester, N. H., who will present a paper on the use of "Oil Fuel under Boilers."

Mr. FISH. Before beginning, let me say that this subject is so immense, so extensive, that in this limited time I will have to let details alone and only treat it in a general way.

OIL FUEL UNDER BOILERS.

BY CHARLES H. FISH, MANCHESTER, N. H.

Of the great problems which to-day interest the manufacturers of New England, there is, perhaps, not one of more importance and therefore none to the solution of which we look with more interest than the question of cheap fuel for our boilers.

To be sure, coal in itself is a cheap fuel, as it is found at the mines; but situated as we are, away from the coal fields, we are completely at the mercy of the various railroads and water lines over which our coal must come; and adding to the expense which the different railroads must incur in transporting such bulk, the profit which each road or line claims as it in turn does its part, the expense at our yards. for handling, we find our cheap coal at the mines, when dumped in front of our boilers, becomes the expensive fuel with which we are all familiar.

Coal is our present standard. It is in general use, and we are all familiar with its good qualities, as well as with its bad ones, but with the fuel in question, petroleum oil, it is different. Although oil has been used in one form or another for many years, and although much has been and is written on the subject, still, viewing it in its relation to its economical use under steam-boilers, it is comparatively new, especially in New England, and apparently but little understood outside of a few who have been led on by its possibilities, and have achieved more or less success in their attempts to obtain a safe and economical application for heat purposes.

Although, as I have said, the application of oil to steamboilers is comparatively new in New England, at the same

time we are astonished at the multitude of burners and apparatus which have been put into other markets, the majority of which are absolutely worthless for practical use. I learn from the United States Patent Office that there have been over five hundred patents granted for oil burners of different kinds.

Oil as a fuel for any purpose has been but little used in New England, but the middle States are full of oil fires, good, bad and indifferent, with all sorts of applications, and we seldom, if ever, hear of any accident occurring to the boilers or employees on this account; neither do we hear of any trouble with the boilers from over-heating or other causes due to the heat.

With these many examples at hand where oil is used as a fuel, and on a large scale, where all nationalities and all grades of intellect are in direct charge of the same, where poor apparatus as well as good are in constant use, it seems as if the question dissolves itself into one of economy and reliability of apparatus.

We must consider briefly the different methods now in use, and in so doing it will be well to follow the classifications already established, namely, first, Oil or Hearth Fires; second, Spray Fires; third, Gas Fires.

OIL OR HEARTH FIRES.

In this class are included all those methods in which the fuel is burned in liquid form. There are several kinds of hearth fires. Herr Busley subdivides this class into pan fires, step fires, drip fires and oozing fires.

The pan fire is the simplest form for burning oil. It consists of a pan or shallow bowl into which the oil runs, and is kept at a uniform depth. The oil is ignited by a torch and burns over the entire surface of the pan.

Step fires seem to follow naturally the pan fire, differing only in the fact that several pans are placed one over the other, like steps, and the oil overflowing from one to the other obtains slightly more oxygen than it does in the still pan.

Neither of these forms are to be considered safe, as there is considerable oil in the fire-box at one time, and the oil is fed to the pans by gravity. Perhaps it will be well to say that these forms are among the oldest, and would hardly be used in practice to-day.

In the drip fire system the oil is allowed to drip into the fire-box through numerous pipes with small openings, and in this way becomes more or less mixed with the air, which is forced through the openings in the grate bars.

Oozing fires. Richardson's furnace and the Locke furnace are good examples of this class. The bottom of the firebox, or in some cases the grate bars, are covered with some porous substance like sand or asbestos, and the oil is introduced from below, the porous substance serving the same function as the wick to a lamp. In some cases, as in the Richardson furnace, combustion is aided by superheated

steam.

SPRAY FIRES.

Taking the next class, the spray fire, we find a large and varied family. The oldest form of spray fires I am told consisted of a narrow orifice, divided longitudinally by a thin partition, on one side of which was the oil and on the other side the steam. This form has from time to time been changed and improved upon, but we find to-day this very burner, in more or less modified forms, in many of the large establishments in the middle States and on the Continent.

The usual form consists of a small or inside pipe enclosed in a larger or outer one. The oil is forced through the inside and steam or air through the outside one, the oil being thus vaporized or sprayed. In some burners the steam is in the inside pipe and oil in the outside one. The effect is practically the same, although I believe more efficiency is claimed in the former case, the mixing being more perfect.

In the Cyclone burner the atomizing is effected by forcing the oil under pressure through a pipe containing a revolving screw. The oil issues in a finely divided condition and meets

a current of air also under pressure. The pressure is obtained usually by a small steam pump.

The Reid burner contains the same concentric pipes, but has an improvement attached by which the steam and air are admitted proportionately.

The Rockwell is another well-known burner or injector of this form using steam.

The Aerated Fuel Company's system consists of burning oil with compressed air. In applying this to horizontal boilers, holes are drilled through the front (usually each side of the door, much the same as in other systems, and above the grate bars, which are not removed), large enough to admit the end of the burner. The burner consists of a small cylinder placed with its axis horizontal and fitted with two inlets, one entering above the horizontal diameter for air and the other entering below for oil. To this cylinder are attached the burners proper. They consist of two concentric tubes, the inner tube being connected with the oil chamber and the outer tube opening into the air space.

The oil supply pipe extends nearly to the bottom of the tank. The air space is connected with the air pump. The pipe from the air pump also enters the top of the oil tank. By this arrangement the pressure of air from the pumps is exerted on the oil in the tank, while a like pressure forces the air through its orifice in the burner. The air mixes with and breaks up the oil, forcing it into the fire-box in a fine spray.

GAS FIRES.

Under this head are classed those apparatus in which fuel is conducted to the fire-box in a gaseous state. Most of these devices generate the gas in the fire-box and by the heat of its own flame, and in so doing meet with one of the greatest obstacles which this class has had to contend with, namely, the stopping up of the pipes by the non-vaporizing of the residuals. These residuals when exposed to great heat coke or carbonize, completely filling up the pipes with a