Improvements in Steam Boiler Furnaces especially Designed to Promote the Combustion of Small and Inferior Qualities of Fuel.
Year: 1893

page_text: Date of Application, 16th Nov., 1893
Complete Specification Left, 9th Aug., 1894-Accepted, 3rd Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Steam Boiler Furnaces especially Designed to
Promote the Combustion of Small and Inferior Qualities
of Fuel.
I, JOHN WATSON SPENCER of Newburn, Newcastle upon Tyne, in the County
of Northumberland, Steel Manufacturer do hereby declare the nature of this
invention to be as follows :-
--
In the construction of steam boiler furnaces especially designed to promote the
combustion of small and inferior qualities of fuel according to this invention,
I divide the ash pit below the fire-bars into two sections by means of a plate
passing from front to back of fire-place along its entire length, and extending
behind the bridge of the furnace.
I then close the front of the furnace ash pit by means of a plate having two
doors, the upper one of which communicates with the ash pit for the removal of
ashes and clinker, and the lower one communicating with the space below the plate
which divides the ash pit into two sections, for the purpose of admitting air behind
the bridge of the furnace.
This lower door, which serves to regulate the quantity of air admitted behind
the bridge may be automatically opened or closed by means of springs or other
suitable arrangement, and thereby allowed to admit a variable quantity of air
behind the bridge as required. Or I may use this door for admitting air behind
the bridge of an ordinary boiler furnace, without having the ash pit closed as above
described.
In the plate which closes the front of the ash pit I also arrange one or more
openings for the admission of air below the fire bars, and so arranged that the air
which supports combustion in the furnace proper may be impelled by steam blast
or other suitable agency under the fire bars without communicating with the space
for admitting air behind the furnace bridge.
Immediately behind the furnace bridge and in the boiler flue, I form a kind of
combustion chamber communicating with the space below the ash pit for admitting
air behind the furnace bridge.
This chamber may be wholly or partially lined with fire brick and filled with
loosely stacked checker bricks for about two thirds or three fourths of its height,
and through which the air admitted behind the bridge has to percolate and thereby
become heated before mixing with the partially unconsumed gases passing over the
furnace bridge.
Especially in cases where very inferior fuel, or fuel containing a large quantity
of moisture has to be used, but even in any case, it is necessary to inaintain a high
nitial temperature in the furnace, and for this purpose I line the roof of the furnace
either wholly or partially with thin fire bricks, so as to prevent the too rapid
absorption of heat from the furnace in contact with the water lowering the
emperature of the gases below that necessary for combustion.
Another part of my invention which may be used in conjunction with the
Improvements herein-before described consists in introducing the fuel into the
urnace in small quantities at a time and at regular intervals by means of a blast of
ir or of air and steam.

page_text: For this purpose I arrange a suitable hopper in front of the boiler above the fire
door, and provided with a self acting feeding arrangement for the purpose of giving
a constant and uniform supply of fuel.
The fuel on leaving the hopper is immediately caught by the blast of air, or of
air and steam issuing from a series of nozzles and deposited on the fire where
required, and in order to deposit the fuel uniformly over the fire the strength of the
blast may be automatically regulated and rendered intermittent in its action.
Dated the 16th day of November 1893.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.
Improvements in Steam Boiler Furnaces especially Designed to
Promote the Combustion of Small and Inferior Qualities
of Fuel.
I JOHN WATSON SPENCER of Newburn, Newcastle upon Tyne, in the County
of Northumberland, Steel Manufacturer do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
In the construction of steam boiler furnaces more especially designed to promote
the combustion of small and inferior qualities of fuel according to this invention,
I divide the ash pit below the fire-bars into two distinct chambers or passages by
means of a plate passing from front to back of fire-place along its entire length
and extending behind the bridge of the furnace. I then close the front of the
furnace ash pit by means of a plate having two doors, the upper one of which
communicates with the ash pit for the removal of ashes and clinker, and the lower
one communicating with the space below the plate which divides the ash pit into
two chambers or passages for the purpose of admitting air behind the bridge of the
furnace.
This lower door, which serves to regulate the quantity of air admitted behind
the bridge may be automatically opened or closed by means of springs or other
suitable controlling arrangement and thereby allowed to admit a variable quantity
of air behind the bridge as required. In some cases I use this door for admitting
air behind the bridge of an ordinary boiler furnace, without having the ash pit
closed as above described.
In the plate which closes the front of the ash pit I provide one or more openings
for the admission of air below the fire bars, and so arranged that the air which
supports combustion in the furnace proper may be impelled by steam blast or other
suitable forcing or current inducing agency under the fire bars without communi-
cating with the space for admitting air behind the furnace bridge.
Immediately behind the furnace bridge, and in the boiler flue, I form a kind of
combustion chamber communicating with the space below the ash pit for admitting
air behind the furnace bridge.
This chamber I prefer to be wholly or partially lined with fire brick and filled
with loosely stacked checker bricks for about two thirds or three fourths of its
height and through which the air admitted behind the bridge has to percolate and
thereby become heated before mixing with the partially unconsumed gases passing
over the furnace bridge.
Especially in cases where very inferior fuel, or fuel containing a large quantity
of moisture has to be used, and indeed it is preferable in any case to maintain a
high initial temperature in the furnace and for this purpose I sometimes line the
roof of the furnace either wholly or partially with thin fire bricks, so as to prevent
the too rapid absorption of heat from the furnace in contact with the water, lowering
the temperature of the gases below that necessary for combustion.

page_text: DESCRIPTION OF THE DRAWINGS.
Fig. 1 shows an end elevation of a Lancashire double flued boiler, Figs. 2 and 3
show a longitudinal sectional elevation through one of the furnaces, and in which
the ash pit below the fire bars a, b, is divided into two distinct chambers or
passages c, c, and d d, by means of a plate e, f, passing from the front to the back
of the fire place along its entire length, and extending behind the bridge b, f, of the
furnace.
"
The front of the ash pit at e, Fig. 2 is closed by means of a plate shewn on a
larger scale in front elevation and cross sectional elevation by Fig. 5; this plate
being provided with one, or more openings g, h, for the admission of air to support
combustion in the furnace proper, and also with an upper door (j) communicating
with the ash pit c, c, for the removal of ashes and clinker; and a lower door (k)
communicating with the space d, d, for the purpose of admitting air below the
plate e f which passing through the passage d' d' is delivered behind the furnace
bridge.
The air which supports combustion in the furnace proper is impelled by steam
blast or other suitable impelling agency through the openings g, h into the
space c, c, below the firebars and is prevented by the plate e, f, from passing into
the space d, d, specially provided for admitting air behind the furnace bridge.
Fig. 6 shews to an increased scale the special tube or tubes communicating with
the openings g or hand the space c c Figs. 1 and 2, and through which the air to
support combustion in the furnace proper is impelled. The steam blast or other
agency of propulsion being regulated by the cock (1) at the admission end, while
the exit end of the tube or passage is provided with a special diaphragm (m)
supported by bars n n, or an equivalent controlling means which admit of the
diaphragm (m) being moved nearer to or further away from the exit end of the
tube in order to equalize the pressure of blast in the
space c, c.
In the case of ordinary boiler furnaces worked under natural chimney draught
and not by forced draught as herein before described, but where it is desirable to
admit air behind the bridge to ensure better combustion and the prevention of
smoke; the space below the firebars is divided into two sections ce and d, d, Fig. 3
and only the lower section d, d, closed by means of a plate at the front end as
already described. This plate together with its door (k) for the regulation of air
admission behind the bridge is shewn to an increased scale by Fig. 4.
Immediately behind the furnace bridge b, f, Figs. 2 and 3, is formed the com-
bustion chamber b, f, o, p, r, s communicating with the space d, d, through which
the air is admitted behind the furnace bridge. This combustion chamber either
wholly or partially lined with fire brick, and filled with loosely stacked checker
bricks as shewn at f, p, Fig. 3 and through which the air passing along the
space d, d, has to percolate thereby becoming heated before mixing with the
partially unconsumed gases passing over the furnace bridge at o; while in order to
prevent the too rapid absorption of heat from the furnace in contact with the water
and thereby lowering the temperature of the gases below that necessary for perfect
combustion I prefer the roof of the furnace to be either wholly or partially lined
with fire bricks as shewn at q, r, Figs. 2 and 3.
In order to ensure complete combustion of the volatile gases passing over the
furnace bridge and thus prevent smoke, it is essential for economical working that
the quantity of air admitted behind the bridge should bear a definite relationship
to the quantity of unconsumed volatile gases passing away from the fire, and in
cases where the fuel is supplied to the fire continuously and uniformly as in
mechanical stoking, and where the quantity of volatile gases passing over the
furnace bridge is uniform, the doors, k, k, may be provided with grids, or fixed in a
position adapted to admit continuously and uniformly just sufficient air behind the
furnace bridge to insure complete combustion.
Where the supply of fuel to the fire and consequently the quantity of unconsumed

page_text: volatile gases passing over the furnace bridge is intermittent as in hand firing the
doors, k, k, are preferably so supported as to be automatically opened or closed by
means of springs or other suitable arrangement and thereby allowed to admit a
variable and intermittent quantity of air behind the furnace bridge as required.
Fig. 7 shews an end view of a boiler shewing to a larger scale the apparatus for
operating the doors.
Fig. 8 is a sectional side view of Fig. 7.
One arrangement of mechanism for automatically opening and closing the
doors kk, is illustrated by Fig. 7 in which t, t and u u, are small cylinders fitted
with pistons, the piston rods passing through both cylinders and connected at the
lower ends by means of the links v, v, with the hell crank levers which are in
turn secured to the hinges of the doors k, k as shewn; y, y, are cocks fitted in the
steam pipes communicating with the boiler and with the underside of the pistons in
cylinders t, t and worked by the hinge pins of the fire doors as shewn.
The cylinders u, u, are fitted with oil or other suitable fluid, and are each
provided with a small pipe z, by which communication is made between the top and
bottom of the cylinder.
The action of this arrangement in opening and closing the doors k, k, is as
follows:
In opening the furnace door the cock y, is simultaneously opened and the piston
in cylinder t, together with the piston in cylinder u, is lifted up by the steam thus
admitted and the door k, opened.
When the piston in cylinder (u) is lifted up the oil or other fluid in this cylinder
passes from the top side of the piston, through the pipe z, to the underside of the
piston, and the door k, remains fully open so long as the furnace door is open for
the introduction of fuel.
When the furnace door is closed, the cock y, cuts off the steam from the cylinder t
and allows the steam on underside of piston in cylinder t, to escape. The weight
of the pistons and piston rods in t and u, together with the links v, and weights w,
and the other parts then tend to force the oil or other fluid from the underside to
the top side of piston in cylinder u, and to close the door k.
Figs. 9 to 12 shew by sections the construction and operation of one of the
cocks y which controls the supply and exhaust of steam to and from the cataract
steam exhausting cylinder t, the cock y being respectively shewn in the figures in
different positions.
Fig. 9 shews the cock y in the position when the fire door is closed and the
cataract exhausting. Under these conditions the steam from the cataract cylinder
passes through the opening y' and thence through the plug y³ of the cock y and out
at opening y (see also Fig. 12).
.
Fig. 10 shews the position of the parts when the door is open 90° and the
cataract is open to the steam.
Fig. 11 shews the like but with the parts in the position they resume when the
door is further opened and the steam is shut off from the cataract.
Fig. 12 shews the parts as they appear with the passage y' in communication
with the exhaust.
The opening y being at a lower level than the main passage through the cock y
the position shewn in Fig. 9 indicates the only one in which said opening y³ can be
operative.
In these figs. (1) indicates the cataract side of the cock y and (2) the
steam side.
The speed at which the oil flows from the bottom to the top of cylinder
determines the speed with which the door k, is closed, and this can be regulated as
desired.
1st by means of the cock in pipe z,
2nd by the weight w, and
3rd by the spring on top side of piston in cylinder u.
1 do not confine myself to the use of the precise arrangement or mechanism for

page_text: automatically opening and closing the doors k, k as the same may be modified
without departing from the principle of construction indicated.
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 :-
In steam boiler furnaces especially designed to promote the combustion of small
and inferior qualities of coal.
1. Dividing the ash pit below the firebars of a steam boiler furnace into two
sections or distinct passages by means of a plate passing from front to back of the
furnace along its entire length and extending behind the bridge of the furnace in
order to allow of air being admitted into the combustion chamber behind the bridge
of the furnace without communicating with the air which supports combustion in
the furnace proper substantially as herein before described.
2. In boiler furnaces where chimney draught only is used; closing the front of
the space below the plate dividing the ash pit into two sections or separate
passages by means of a door or doors for the purpose of regulating the admission
of air behind the bridge substantially as shewn by Figs. 3 and 4 of the drawings.
3. Where forced draught is used; closing the whole front of the ash pit by
means of a plate having two or more doors the upper door for the removal of ashes
and clinker from below the fire bars, and the lower door for regulating the admission
of air behind the furnace bridge, substantially as described and illustrated by Figs. 2
and 5 of the accompanying drawings.
4. The construction or arrangement and use of means or apparatus for auto-
matically opening and closing the door, or doors, which regulates the admission
of air to the combustion chamber behind the furnace bridge, substantially as
hereinbefore described and illustrated by Fig. 7 of accompanying drawings.
5. The general arrangement or combination of parts for facilitating the proper
supply and control of air separately to the furnace grate and to the combustion
chamber in rear of the bridge as set forth and shewn by the drawings.
Dated the 9th day of August 1201
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.