IMPROVEMENTS IN BOILER FURNACES
Year: 1883

page_text: LETTERS PATENT to Herbert John Haddan, of Kensington, Middlesex for
an Invention of IMPROVEMENTS IN BOILER FURNACES a communication to
him from abroad by Ezra W. Van Duzen, of Cincinnati, Ohio, United States
of America
COMPLETE SPECIFICATION filed by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 5th March 1883.
"
HERBERT JOHN HADDAN, of Kensington, Middlesex 'IMPROVEMENTS IN
BOILER FURNACES," communicated to me from abroad by Ezra W. Van Duzen,
of Cincinnati, Ohio, United States of America
.
This invention relates to boiler furnaces. The main objects of my invention are
to prevent smoke in the burning of soft bituminous coal, etc., and to secure a
perfect feed of the air to the furnace chambers.
In the drawings: Figure 1 is a longitudinal vertical sectional view, parts being
broken away, of a boiler furnace embodying my improvements.
Fig. 2 is a top view of the same, a portion of the boiler above the furnace.
chamber being broken away to show the interior.
Fig. 3 is a front elevation on the line xx, Fig. 1.
Fig. 4 is a vertical cross section on the line y y, Fig. 1.
Fig. 5 is a horizontal sectional view taken through the bridge wall on the
line sz, Fig. 1.
Fig. 6 is a vertical sectional view illustrating a modification of the bottom of the
furnace under the arch.
Fig. 7 is a plan view of one form of the bottom of the furnace under the arch.
Fig. 8 is a plan view of a modification in the form of the bottom of the furnace
under the arch.
Fig. 9 is another modification in the form of the bottom of the furnace under
arch,
Fig. 10 is a horizontal sectional view of the double injector nozzle.
Fig. 11 is a horizontal sectional view illustrating a modification of the double

page_text: Referring to the drawings, A designates an ordinary boiler; B, the outer brick
wall of a furnace; C, the grate bars; and D, the ordinary furnace chamber.
Considerable inconvenience and expense is experienced, in this class of furnaces,
by the burning out of the pipes in which the air is heated and fed into the furnace
chamber. But by my construction this is obviated, as the pipes are not near
enough to the fire to burn out or to bend and warp from too great heat.
In order to effect the thorough and proper heating of the air in the blast pipes
before it is admitted into the furnace chamber, and yet secure the said pipes against
damage by the heat of the furnace, I provide one or more transversely disposed
distributing pipes or chambers, E, placed above the door, F, and built into the
wall. These chambers E are provided with air distributing orifices or jets, G, as
shown.
HH designate air supply pipes, which are brought into the furnace chamber at
or near the bridge wall hereinafter described, are then carried along inside or near
the top of the furnace chamber to the front thereof, and from thence into the
distributing pipes or chambers E E. These pipes H H are thus extended along
the top and side of the furnace chamber at a sufficient distance from the fire to
obviate any damage to them by the heat, and the said pipes may, if desired, pass
down inside the brick wall instead of in front of it.
The air may be supplied to the pipes H H by means of a fan or cylinder blast,
or by means of a steam jet or injector, as hereinafter described.
I is an approximately T-shaped injector for supplying the pipes H H, which is
enclosed in a four joint casing or union, J, and from which extends the steam
pipe, K, that taps the boiler. L is the air supply pipe, which enters the four joint
union opposite the injector. The pipes H H enter the four joint union at opposite
sides, and the jet orifices, M M, in the ends of the head of the T-shaped injector
face these pipes. The four joint union is preferably provided with projecting
cones, N N, that enter the pipes H H and connect the same with the union.
Air is supplied through the pipe L and steam through the pipe K into the
injector from which it is discharged in a jet at the orifices M M. The, air is thus
driven through the branches H H into the furnace chamber, and is greatly
accelerated by the heating of the said pipes H H inside the latter.
It is desirable to inject into a furnace a minimum quantity of steam with the
heated currents of air, and this object the above described mechanism completely
secures.
O designates a bridge wall that is arranged in rear of the grate bars C, and does
not quite project up to the boiler, so that a space, P, is provided above the main
portion of the arch. This space furnishes additional room for the proper mingling
of the combustible gases, and also allows the heat to come into contact with much
more boiler surface. There is a thin brick partition, Q, built up from the top of
the bridge wall O to reach the boiler.
R is an arch sprung from the rear of grate bars C, and extending through the
wall O. This arch furnishes a supplemental fire chamber or furnace, through
which the products of combustion must pass, and become. heated and consumed
either in the arch or in the combustion chamber in the rear thereof.
S is the bottom of the arch chamber R. It is made inclining upward from the
front of the arch for two reasons: first; to contract the arch at the rear to insure a
more perfect combustion of the gases: and, second, to keep the area of the arch at
its rear the same, so that it will not be obstructed by cinders and ashes accumu-
lating in the rear. This grate surface is perforated or made with openings through
it, and with an air space, T, underneath to keep the plate from becoming too
highly heated, and to supply air to that part of the combustion cliamber within
the arch R where the coked coal is consumed.;
I have shown three forms of bottoms for the furnace within the arch R, one
form being represented by the letter U, Figures 6 and 8 of the drawings. Figs. 5
and 7 show a perforated metal plate, designated by the letter V, adapted to be
used in lieu of the bars U shown in the modification illustrated in Fig. 6. Fig. 9°

page_text: Figs. 7 and 8.
In order to more perfectly supply air to the combustion chamber, I make the
bridge wall O hollow or with openings, W, which openings communicate with
registers, X,, below the furnace chamber, for supplying any desired amount of air.
In order to heat the air before admitting it to the arch chamber R, I provide
brick posts or winding air passages through the hollow bridge wall O to check the
too rapid passage of the air which enters the arch R through openings, Y, in either
side of the arch.
A very important result is obtained by having the bottom of the arch R inclined
upwardly towards the rear. It prevents the coal and incandescent fuel from
working backwards to obstruct the flue. It preserves the flue area the same and
allows the fuel to be stirred, carrying the ashes through the grate, and causes the
fuel to incline towards the furnace chamber.
By making the bridge wall O hollow it prevents a too high heating of the wall
forming the arch, which prevents a too high degree of heat to the wall and that
portion of the boiler over it.
Other forms of making hollow walls each side of the arch R may be employed
instead of the form herein shown.
In the modification shown in Fig. 6, Z designates a perforated ledge at the rear
of the grate bars Ū to admit air into the rear chamber, A 2, to furnish oxygen to
support combustion.
In the modification shown in Figure 11, the four joint union is dispensed with,
and, in lieu thereof the air pipe is formed with two branches, B2 B2, to which
the pipes H H connect. The jet orifices of the steam jet project into these branches
and discharge the steam through the same.
While the supply of air admitted above the incandescent fuel should be
abundant, the amount of air admitted from below the fire should be regulated,
more especially in those furnaces where the firing is not regular. In order to
secure regulation of the amount of air admitted to the furnace from below, I
provide one or more doors, by opening and closing which the amount of atmospheric
air admitted can be regulated to suit varied conditions or requirements. These
doors may be provided with registers or dampers, if desired, and are preferably
swung from the top, as shown: but they may be swung from either or both sides
or from the bottom.
C2 designates a door closing the opening leading from the ash pit to the
perforated plate in the bottom of the supplementary furnace R, which is hung upon
hinges, D 2 D 2, and is provided with a crank rod, E 2, for operating, leading to
the front of the furnace
If desired, the registers X X may be dispensed with, and openings be provided
in their stead leading into the hollow bridge wall, so that all the air admitted to
the supplemental furnace and hollow bridge wall, except that which enters from
the main furnace chamber, can be controlled and regulated by the door C 2, the
said openings being formed inside the compartment that the door closes.
The operation and advantages of my invention are obvious. The construction is
very simple, inexpensive, and efficient.
I claim as my invention:
1. In a boiler furnace, the combination, with a transverse distributing pipe or
chamber, of one or more air supply pipes extending along the top and inside of the
furnace chamber and connected with the distributing pipe; as set forth.
2. In a boiler furnace, the combination of the supply pipes H H, an air pipe L, a
steam pipe K, and a double injector I; all combining to supply air to the furnace,
as set forth.
3. In a furnace chamber having the arch R and bridge wall O forming a
supplemental fire chamber, the space P above the said bridge wall; as and for the
purpose set forth.
4. A boiler furnace composed substantially of the main furnace chamber, and

page_text: the supplemental furnace formed within the arch of the bridge wall and provided
with a bottom under which is formed an air space; as set forth.
5. In a boiler furnace, a secondary or supplemental furnace formed in a hollow
bridge wall, which is provided with air openings, and the bottom of the arch
chamber; as set forth.
6. In a boiler furnace, the bridge wall having the air passages and conveying air
into the secondary furnace; as set forth.
7. In a boiler furnace, the combination of the main furnace chamber, the grate,
the bridge wall at the rear of the grate constructed with the arched chamber R,
the bottom of the said arched chamber inclined upward from front to rear, and the
air space under the latter; as set forth.
8 The combination, with a boiler furnace constructed substantially as herein
described, of one or more doors arranged below the level of the grate bars, for the
purpose of controlling the amount of atmospheric air admitted to the incandescent
fuel from below the grate bars; as set forth.
In witness whereof I the said Herbert John Haddan have hereunto set my
hand and Seal this fifth day of March in the year of Our Lord One thousand
eight hundred and eighty three.
T T ITADDA AT