IMPROVEMENTS IN FURNACES
Year: 1885

page_text: I, HERBERT JOHN HADDAN, of 67, Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of said invention for IMPROVEMENTS IN
FURNACES, a cominunication to me from abroad by Joseph Warren Brightman, of
Cleveland, United States of America, Manufacturer, and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :-
This invention relates to improvements in furnaces and attachments designed
more especially for steam-boilers, the primary object being to improve the general
construction and arrangement of the furnace and attachments and render the same
more economical, and substantially smokeless in the consumption of fuel, and more
convenient to operate. Pertaining to the details of construction, a further object
is to provide an improved automatic coal-feeding device.
A further object is to provide inclined grates composed of stationary and
movable sections arranged alternately, each section having overlapping shelves that
interlock with the shelves of the next adjacent sections, and so arranged that the
air-supply enters between the shelves approximately in a horizontal direction,
to the end that the fuel does not clog the air-spaces, that fine or coarse coal may
be used at pleasure, and that no coal is wasted through the grates however fine the
coal may be that is fed to the furnace.
A further object is to support the movable sections of the grates, on rock-arms,
that are connected with the feeding apparatus in such a manner that these sections
are given a reciprocating movement end wise, to feed the coal toward the rear of
the furnace.
A. further object is to provide an improved device for discharging jets of air, by
means of a steam-blast, into the furnace above the fire to aid in burning the gases,
to the end that no smoke is formed.
In the accompanying drawings Fig 1 is a front view in perspective of a furnace
and attachments embodying the invention.
Fig 2 is a side view in perspective showing the interior of the furnace, a portion
of the grate sections being removed so that the one section in the foreground may
be more clearly shown.
Fig 3 is an elevation in longitudinal section through the centre of the furnace.

page_text: Figs 4, 5 and 6 are views in detail illustrating the mechanism for discharging
jets of air by means of a steam-blast, into the furnace above the fire, and herein-
after more fully described.
A represents the boiler, B the setting, B' the bridge-wall, and C the boiler front,
the latter having doors c arranged in the usual manner affording access to the
boiler-flues.
D are upright iron plates arranged next the setting on either side of the furnace,
and form the frame work for supporting the principal part of the mechanism
connected with the furnace. These plates support the cross-bars D¹, that support
the stationary grate-sections.
To these plates and near the lower edge, are respectively pivoted the levers E,
that in pairs, support respectively the rock-arms and attached cross-bars El and E³,
that in turn support the movable grate-sections. The front end of the levers E
rest respectively on wedges d, that in turn rest on ledges d' projecting laterally
from the plates D. By means of these wedges, the levers E may be tilted more or
less to accurately adjust in a vertical direction the rock-arms and movable grate-
sections, that, as aforesaid, rest on the cross-bars of these rock-arms. The levers E
have each an upwardly projecting toe e, that fits into the concaved lower end of a
rock-arm, forming a pivotal bearing for the latter.
The movable and stationary sections of the grates respectively F and F¹, are
substantially alike, except that the former have depending lugs f, for embracing
the rock-bars E¹ and E and the latter have similar lugs f¹ arranged near the ends
of the sections, for embracing the stationary bars D¹.
Each grate section has a series of shelves f² arranged along the sides thereof,
about horizontal in a lateral direction, but usually inclining downward and rear-
ward a trifle. When the different grate-sections are in position, the one set resting
on the stationary bars D¹, and the other set resting on the rocking bars E1 and E2
as aforesaid, the shelves from the next adjacent sections interlock each other, leaving
air-spaces between the interlocking shelves, and by means of the wedges d already
described, the movable grates may be raised or lowered to bring the shelves of
these sections midway, vertically, between the shelves of the stationary section, and
thereby provide uniform air-spaces.
Between some of the shelves of the grate-sections shown in Fig 3, are shown in
dotted lines the positions that the intermediate shelves from the adjacent sections
would occupy, from which it will be seen that the successive shelves, up and down
the sections, overlap each other some distance in the direction lengthwise of the
furnace. With the ordinary grates, having vertical air-spaces, the coals, ashes, etc,
crowd into, and, more or less, clog these air-spaces, and much of the fine-coal is
likely to pass between the grates and be wasted.
With the improved grates the coal rests upon the shelves ƒ³, and has no tendency
to enter the air-spaces, but on the contrary, is drawn away from them as the coal
is fed down the incline of the grates, leaving the said air-spaces unobstructed, and
the body of the coal next the grates, by reason of its breaking over the edges of
the successive shelves, is in a loose condition near the air-spaces, so that the air
readily penetrates the mass of coal, and if the coal has, as aforesaid, no tendency to
enter the air-spaces, it is evident that no coal, however fine, it may be, is wasted
by passing through the grates.
The rock-bar E¹ has attached the connecting rods g, that in turn are connected
with the oscillating bar G, by means of which the movable sections of the grates
are given a slight reciprocating movement end wise to feed the coal slowly down
the inclined grates at the rear end of which and depressed some distance below
are located a set of ordinary grates H extending to the bridge-wall. Between the
inclined grates and the grates H, are the upright grates H¹, usually divided into
two or more sections, according to the width of the furnace, and each section is
hinged at the bottom to the cross bar that supports the front end of the grates H,

page_text: and are provided respectively with rods h leading to the front of the furnace, by
means of which the sections H₁ are held in an upright position, as shown in the
back ground in Fig 2, and at the left hand in Fig 1, or the respective sections may
be lowered, as shown in Figs 1 and 2, to rake out the clinkers or to remove the
fire. The ash-pit extends under the grates H, and an air supply is therefore had
through all the grates.
I is a hopper in which the coal is placed and from which it is automatically fed
to the furnace. The plate I¹, that forms the bottom of the hopper, extends over
the upper end of the inclined grates, and an opening is had above this plate
extending the length of the hopper, and of sufficient width in a vertical direction,
for the passage of coal to the furnace.
J is a block that lays upon the plate I', and is connected by arms J¹, with the
oscillating bar G, by means of which the block J is reciprocated toward and from
the furnace. The bar G is supported by and pivoted to the brackets L, that are
secured to the frames D. One or more arms G' extend forward from the bar G,
for attaching a lever for moving the block J by hand when desired. An arm gi
attached to the bar G, has a wrist g2, to which is attached the connecting rod m
connected with a crank that is attached to the horizontal shaft M, on which is
also mounted the worm-gear M³ that engages the worm n mounted on the vertical
shaft N.
This latter shaft, above, is intergeared as shown, with the horizontal shaft O, on
which is mounted the driving cone O¹.
The shafts M, N, and O are journaled in suitable boxes supported in a frame P,
that is bolted to the plate C. Usually an arm gl is provided at each end of the
bar G so that the driving mechanism may be located on either side of the furnace
that is most convenient for transmitting power to the same.
When other power
is not accessible, a small engine is usually employed to drive the feeding device.
Various modifications of the driving mechanism can of course be made according
to circumstances.
C is a shelf integral with, or bolted to the front plate C, and rests on the
frames D, as shown more clearly in Fig 2, and supports the mason work that
forms a lining for the front plate C. On the plates Crests an inverted T-shaped
plate C. Through the upwardly projecting tongue of this plate are openings c¹,
see Figs 4 and 5, with cross-bars c², the central portion of which forms a hollow
hub c³, the hole in which inclines rearward and downward usually at about the
same angle as the inclined grates. The openings c¹ are usually about four inches,
more or less, in diameter, and from four to six in number according to the width of
the furnace, and are distributed as shown in Fig 2. On the furnace side in front
of each opening c¹ is set a tweer c' that rests on the flange of the plate C³, with
the bore of the tweer inclined at about the same angle as the hollow plug Q, that
is inserted in the bore of the hub c³. The opening in the furnace end of this plug
is small, usually about one eighth of an inch, more or less, in diameter. The
opposite end of the plug is provided with a toe or elbow Q1, that is connected in
the steam-pipe R, leading to the steam-space of the boiler.
Between the upright tongue of the iron C² and the plate C, is an air-chamber S,
extending the width of the furnace, and that by means of the openings c¹, is of
course in open relation with the tweers. The chamber S, at one or both ends, is
open, to admit air, or may be connected with chambers in the setting, or other
devices, for heating the air. The steam, admitted through the pipe R, is discharged
in jets, through the hollow plug Q inside the tweers, and these steam-jets draw in
currents of air from the chamber S, and the commingled air and steam are
discharged into the furnace in the direction of the opening over the bridge-wall.
The side walls of the furnace next the bridge-wall should be brested out toward,
and join the boiler as low as practicable so as to shut off the passage-way along
the sides of the boiler in order that the entire products of combustion be
compelled to pass through a comparatively limited space between the bridge-

page_text: wall and boiler for the purpose of concentrating the heat at this point to ignite
the gases.
The coal, as it is fed along down the inclined grates, is in a thin layer at the
upper end thereof, but increases in thickness toward the bottom, and on these
grates is where the cooking is done, and consequently the most of the gases are
expelled before the coal is discharged into the body of the fire on the grates H.
Above the grates H, and next the bridge-wall, the depth of coal is such, that the
heat is intense, and the gases expelled in the cooking process, commingled with
the air admitted through the tweers, to render the gases more combustible, are
passed directly over the hottest part of the furnace, and as they pass the bridge-
wall, the volume of commingled air and gases is ignited, and burns fiercely at the
rear of the bridge-wall, the flames usually extending to the rear end of the boiler
and into the boiler-flues.
The gases are usually entirely consumed so that no smoke is formed.
The automatic feeding device is easily regulated to feed the desired quantity of
coal so that the fire is regular. A supply of coal should be kept in the hopper to
prevent cold air from entering the furnace.
The dumping grates H can be let down at any time, and the clinkers and ashes
removed without deadening the fire in the least. It will be observed that the
ash-pit is always open, and the draft should be controlled by a damper in the
chimney, or in the flue leading to the chimney.
Coal-dust, and cheaper grades of coal are used to advantage in this furnace.
As compared with ordinary furnaces, the labour of stoking is reduced about one
half, the capacity of the boiler is largely increased, and the consumption of coal is
considerably less.
Having now particularly described and ascertained the nature of said invention
and in what manner the same is to be performed, I declare that what I claim is
1. Inclined furnace grates, composed of stationary and movable sections, the
latter provided with suitable actuating mechanism for reciprocating the same
endwise, to feed the coal rearward in the furnace, substantially as set forth.
2. Inclined furnace grates composed of stationary and movable sections arranged
alternately, each section provided with a series of laterally projecting shelves on
either side that interlock with the shelves of the next adjacent sections, the
successive shelves overlapping each other in the direction lengthwise of the
sections, substantially as set forth.
3. In a furnace, the combination with grates inclined from the front downward
and rearward, of grates at the rear portion of the furnace depressed some distance
below the lower end of the inclined grates, with dumping grates arranged between
the inclined and lower grates, substantially as shown.
4. In a furnace, a coal-feeding hopper located in front of the furnace, a sliding
block operating in the hopper to feed the coal into the furnace, actuating
mechanism, preferably as shown, for reciprocating the block, substantially as
set forth.
5. In a furnace, the combination with an automatic feeding device arranged
in front of the furnace, of inclined grates composed of stationary and movable
sections inclined from the front rearward and downward, the inovable sections
supported by rock-arms, and attached cross-bars the latter being connected with
the feeding mechanism so that the movable sections are reciprocated endwise by
the same driving mechanism that actuates the feeding device, substantially as
set forth.
6. In a furnace, an air-chamber, located above the coal-feeding apparatus,
leading to the furnace, with suitable openings from said chamber leading into the
furnace, a steam-pipe connected with hollow plugs arranged to discharge a jet
of steam into each of said openings, and arranged to form a steam-blast for
discharging commingled steam and air into the furnace in the direction of the
opening on the bridge-wall, substantially as set forth.

page_text: 7. Inclined furnace grates, composed of sections, each section having a series
of laterally projecting shelves on the sides, the shelves of adjacent sections
interlocking, and the successive shelves, up and down the incline, overlapping each
other, and so arranged that air-spaces are had between the shelves for admitting
air in approximately a horizontal direction.