Improvements in Steam Boiler and other Furnaces.
Year: 1894

page_text: Date of Application, 27th Nov., 1894-Accepted, 29th Dec.. 1894
COMPLETE SPECIFICATION.
Improvements in Steam Boiler and other Furnaces.
I, BENJAMIN WHITE MAY, Manufacturer, residing at 163 La Salle Street,
Chicago, Cook County, Illinois, United States of America, do hereby declare the
nature of my invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of my invention is to provide a simple, economical and efficient
furnace, particularly adapted for use in connection with boilers and brick kilos ;
and my invention consists in the features combinations and details of construction
hereinafter described and claimed.
In the drawings, Figure 1 represents a vertical elevation in section, showing my
improved furnace as used in connection with a boiler; and Fig. 2 a transverse
vertical section taken on line 2 of Fig. 1, looking in the direction of the arrow.
It is well known in the art to which this invention relates-and especially in the
burning of soft or bituminous coal-that the same will smoke very rapidly, and to
such an extent that the flues of a boiler rapidly choke and scale, so that they have
to be cleaned out frequently. This adds largely to the expense of running the
same, and, in a measure, makes the use of soft and bituminous coal objectionable.
To overcome this objection, and provide a furnace in which soft or bituminous coal
may be burned economically and efficiently, and the greatest amount of heat be
extracted therefrom, is the principal object of my invention.
In constructing my impiovement and using it in connection with a boiler, I
provide a boiler, A, of the ordinary flue type, at the front end of which is provided
a chamber, a, which leads to the smoke stack. The boiler is supported in the
usual manner upon the side walls, B, and is arched over with fire or ordinary
bricks, b, as is usual in such instances. In describing the furnace, I will describe
but one, but it will be understood that it may be used with a battery of boilers
erected side by side, so that one description will answer for all.
In the construction of a furnace proper, I use a suitable framework, C, preferably
made of cast iron of the desired size and shape-though any other desired material
may be used and which encloses the ash pit, c. I provide this framework with
ledges, D, D', D². The ledge, D2, forms a brace which runs across from side to
side of the frame Upon these ledges I support the grate bars, E E', and prefer to
make them in two parts; but it will be understood that the brace rod can be done
away with and the grate bars be made in one piece and extend from end to end of the
furnace. These grate bars can be made hollow, for the purpose of holding water
to keep them cool or extend the evaporating surface of the boiler. I prefer to
provide the forward end of the furnace with a cast iron hood, G, which incloses
and covers the front set of grate bars, forming what I term a "primary combustion
chamber," 9, and separate this primary combustion chamber from the rear set of
grate bars by means of a bridge wall, H, which is provided with a sliding door, h,
arranged to be operated by a weighted lever, I, thus forming what I term a
"secondary combustion chamber," G. This lever is provided with a weight or
ball, i, to counterbalance the weight of the door, h, so that the same may be
operated with the least possible amount of exertion. Instead of having the furnace
projecting from the front end of the boiler, both combustion chambers may be
placed immediately under the boiler, and the door in the bridge wall opened
downwards or sideways, thus obtaining the advantage of all the beat generated in
both the primary and secondary combustion chambers.

page_text: The primary combustion chamber is provided with a door, K, through which air
may be admitted to the chamber to support combustion or fuel added to the fire
when desired, or for any other useful purpose; while the ash pit is provided with a
door, L, for the purpose of removing the ashes, or for the admission of air to either
the primary or secondary combustion chambers.
In operation I start a fire in the combustion chamber, adding a small amount of
coal, so that the least possible amount of smoke will be created. I then open the
door slightly, so that sufficient air will enter to support combustion, while the door
in the bridge wall is opened, so that the smoke and heated gases will pass directly
in through the secondary chamber to the back of the boiler, return through the
up-take, a, where it passes to the chimney. When the fuel in the primary com-
bustion chamber has been sufficiently burned or become coked, I push the hot bed
of coals, or the greater portion thereof, back into the secondary chamber. I then
close the door in the bridge wall and supply a fresh amount of coal to the primary
chamber. Combustion immediately takes place in the primary chamber and it
becomes a down-draft furnace, so that the gases distilled from the burning fuel pass
through the ash pit and up through the burning fuel in the secondary combustion
chamber, where the combustion of these gases and the fuel contained in such
chamber is completed, thus minimizing the chances of forming or creating smoke.
As soon as this second lot of coal or fuel in the primary combustion chamber has
become coked, the door in the bridge wall which separates both these chambers is
opened and the coked fuel pushed back again into the secondary chamber. The door
is then again closed and a small amount of fresh fuel added to the primary combustion
chamber, so that the distilled gases have to pass down again through the ash pit
and up through the grates of the secondary combustion chamber, where it is
consumed. This process is kept up as often as seems necessary, or as long as it is
desired to keep a fire under the boilers; and as fast as the coal in the initial
combustion chamber is coked, the larger portion of it is pushed back upon the
second set of grate bars in the secondary chamber, leaving only enough in the
primary chamber to support combustion again, when fresh fuel is added.
In using my improved furnace in connection with a brick kiln, I build a furnace
exactly as above described, and build the kiln entirely over the secondary com-
bustion chamber, in the position occupied by the boiler shown in the drawings in
Fig. 1, leaving an arch of the desired size immediately over the second set of
grates, so as to form a combustion chamber of the desired size. The brick in the
kiln is laid in the usual manner, so that the interstices or flues are provided in such
manner that the heated gases may pass up through the bricks and thoroughly bake
or burn the same, thus permitting soft coal or hard coal to be used in connection
with the baking of brick. The advantages, therefore, which I derive from the use
of my furnace in connection with brick kilns are that the danger of smoke is almost
entirely obliterated, as well as economy gained in the use of fuel, for the reason that
it is only necessary to use small amounts of fuel at a time and that bituminous coal
may be used in the furnace without creating smoke.
While I have described the construction of my invention with more or less
minuteness as regards details, I do not desire to be limited thereto unduly, any
more than is pointed out in the claims. On the contrary, I contemplate all proper
changes in form, construction and arrangement, the omission of parts and the use of
equivalents, as circumstances inay suggest or render expedient.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :
1. In a heating apparatus, the combination of a furnace having a primary
chamber in which fuel is partially consumed, a secondary chamber in which the
combustion of fuel is completed, a bridge wall separating such chambers, and a
door in such bridge wall through which fuel may be pushed, substantially as
described.

page_text: 2. In a heating apparatus, the combination of a furnace having a primary
combustion chamber for partially burning fuel provided with a door arranged above
the point of burning fuel for the admission of air, etc., a secondary combustion
chamber for completing the combustion of fuel and having its opening for the
admission of air and products of combustion below the point of combustion, a bridge
wall separating such chambers, and a door in said wall through which partially
consumed fuel may be passed, substantially as described.
3. In a heating apparatus, the combination of a furnace having a primary down-
draft combustion chamber for partially burning the fuel, a door in such chamber for
the admission of air and fuel, a second up-draft combustion chamber in which the
combustion of the fuel is completed, a bridge wall separating such chambers, a door in
such wall through which the partially burned fuel is passed, means for opening and
closing such door, an ash pit beneath such chambers through which the first products
of combustion pass, and a door in the wall of such pit for the admission of air or
removal of ashes, substantially as described.
Dated this 27th day of November 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.