IMPROVEMENTS IN STEAM BOILER FURNACES, AND IN ARRANGEMENTS FOR REGULATING THE SUPPLY OF AIR AND FUEL THERETO
Year: 1872

page_text: LETTERS PATENT to Joseph Knowles Broadbent, of the City of Man-
chester, in the County of Lancaster, Engineer, for the Invention of
"IMPROVEMENTS IN STEAM BOILER FURNACES, AND IN ARRANGEMENTS FOR
REGULATING THE SUPPLY OF AIR AND FUEL THERETO.”
Sealed the 18th February 1873, and dated the 2nd September 1872.
PROVISIONAL SPECIFICATION left by the said Joseph Knowles Broad-
bent at the Office of the Commissioners of Patents, with his Petition,
on the 2nd September 1872.
I, JOSEPH KNOWLES BROADBENT, of the City of Manchester, in the
3 County of Lancaster, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM BOILER FURNACES, AND IN ARRANGE-
MENTS FOR REGULATING THE SUPPLY OF AIR AND FUEL THERETO," to be as
follows:-
Firstly. The object of my Invention is to arrange the doors of a steam
O boiler furnace, and combine therewith mechanism for supplying. air
above the fire-bars, so that the stoker will be in.a measure compelled to

page_text: supply the fuel first on one side and then on the other side of the
furnace alternately, this mode of firing being that which promotes the
most perfect consumption of the smoke, as the gases generated from the
fuel thrown upon one side of the fire are ignited by the incandescent fuel
on the other side of the fire alternately. And my Invention consists in
hinging two doors together at the centre of the mouth of the furnace, so
that when one door is fully open to admit of " firing" it comes in
contact with the other door, which must then be fully shut, in which
position of the two doors the lid or door through which the air is
supplied to the furnace above the fire-grate will be opened to its fullest
extent (by a cam on the door, there being one on each door), and the air
lid will have left a sliding bolt at liberty to descend by its own gravity,
and enter a hole in the door which is shut, and it will also leave a corre-
sponding bolt for the other door ready to enter a hole in it when shut,
so that both doors will thus be secured during the time the air lid is
open and while it is closing, the speed of which closing is regulated by
apparatus similar to that described in the Specification of Letters Patent
granted to me, and numbered 19, and dated the 3rd of January A.D.
1867. When the air lid is fully shut arms upon or in connection
with it have lifted the sliding bolts, and this allows either door to be
opened; but if required the mechanism may be arranged to withdraw
each bolt alternately. The air supply from the lid passes through a
space in the hollow door and then to the fire. The doors are hinged
in an inclined position so as (when partly shut) to close by their own
gravity.
Secondly. My Invention relates to means for regulating the supply of
air to the solid or incandescent part of the fuel through the grate bars
without interfering with the intermittent supply above the grate bars for
consuming the smoke and combustible gases, such supply of air through
the grate bars being made to depend upon the pressure of the steam,
the supply of air being diminished or shut off when the pressure of
the steam is in excess of that fixed upon, and turned fully on when the
pressure returns to the maximum. By this mode of "damping" the
fire the full force of the chimney draught is maintained, and the smoke
and combustible gases are consumed by the air admitted above the fire-
bars, even when the suppuly of air through the fire-bars is entirely shut
off. By the ordinary mode of "damping" the chimney draught acting
...upon the fire is diminished, and a large part of the gases generated in
st

page_text: the furnace pass up the chimney unburnt. This part of my Invention
consists in applying frames to the front of the ash-pit of the furnace, so
as to close it in, which frames are hinged to turn away when required to
allow ashes to be removed, and they are filled with pivotted plates or
boards to open and close like a Venetian blind (or any other valvular
arrangement may be used), and in connecting the pivotted plates or
valves by rods and levers with one side of an elastic diaphragm, having
the pressure of the steam in the boiler acting on the other side.. The
diaphragm is weighted by a lever combined with a weight lever arm
placed at an angle, or by a weight and spring combined.
Thirdly. My Invention relates to the furnaces of vertical boilers, and
consists in forming a partition or deflector in the fire-box of fire-brick.
material above the fire, or it may be a hollow metal partition in an
inclined position in communication with the water space of the boiler.
This partition causes all the gases from the burning fuel to come near to
the furnace door before passing to the flue above the partition, so that
air admitted at the fire-door by suitable apparatus, similar to that
described in the Specification of the said Letters Patent granted to me,
as aforesaid, will mix with and ignite the unconsumed gases.
Fourthly. My Invention relates to those fire-bars which can be.
"rocked" to break up clinkers and discharge ashes, and thus keep the
air spaces in and between the grate bars open. Such grate bars have
hitherto been made with two or more rows of parallel slots in a straight-
line for air, but such bars are very liable to break from unequal
expansion and contraction; and this part of my Invention consists in
making the bars zig-zagged or wavy laterally, so as to bend and give
way more easily to unequal expansion and contraction. This part of
my Invention further consists in placing the lengthway of such rocking
bars in the lengthway of the furnace supported by a cross stay in the
middle instead of across, the furnace as hitherto; and this part of my
Invention, also further consists in forming the pivots for rocking the
bars parallel to the axis of the pivots on which the bars rock, and in
rocking them by a lever (on a fixed stud or fulcrum) having a socket
for a lever handle, which is passed through a slotted hole that limits the
length of the rocking movement, the lever handle being formed (upon
the principle of a butler's tap 'key), so that it can only be inserted and
withdrawn from the socket in the central position when the surfaces of
the rocking bars are in the same line. This latter arrangement is

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Joseph Knowles Broadbent in the Great Seal Patent
Office on the 28th February 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
KNOWLES BROADBENT, of the City of Manchester, in the County of
Lancaster, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of September, in the
year of our Lord One thousand eight hundred and seventy-two, in
the thirty-sixth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Joseph Knowles Broadbent,
Her special license that I, the said Joseph Knowles Broadbent, my
executors, administrators, and assigns, or such others as I, the said
Joseph Knowles Broadbent, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN STEAM BOLLER FURNACES, AND IN ARRANGE-
MENTS FOR REGULATING THE SUPPLY OF AIR AND FUEL THERETO," upon the
condition (amongst others) that I, the said Joseph Knowles Broadbent,
by an instrument in writing under my hand and seal, should particu-
larly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Joseph Knowles Broadbent, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained

page_text: in and by the following statement and accompanying Drawings (that
is to say) :-
Firstly. The object of my Invention is to arrange the doors of a steam
boiler furnace, and combine therewith mechanism for supplying air
above the fire-bars, so that the stoker will be in a measure compelled to
supply the fuel first on one side and then on the other side of the
furnace alternately, this mode of firing being that which promotes the
most perfect consumption of the smoke, as the gases generated from the
fuel thrown upon one side of the fire are ignited by the incandescent fuel
on the other side of the fire alternately. And my Invention consists in
hinging two doors together at the centre of the mouth of the furnace, so
that when one door is fully open to admit of firing it comes in contact
with the other door, which must then be fully shut, in which position of
the two doors the lid or door through which the air is supplied to the
furnace above the fire-grate will be opened to its fullest extent (by a
cam or projection on the door, there being one on each door), and the
air lid will have left a sliding bolt at liberty to descend by its own
gravity, and enter a hole in the door which is shut, and it will also leave
a corresponding bolt for the other door ready to enter a hole in it when
shut, so that both doors will thus be secured during the time the air lid
is open and while it is closing, the speed of which closing is regulated
by apparatus similar to that described in the Specification of Letters
Patent granted to me, and numbered 19; and dated the Third of January,
in the year of our Lord One thousand eight hundred and sixty-seven.
When the air lid is fully shut arms upon or in connection with it have
lifted the sliding bolts, and this allows either door to be opened; but if
required the mechanism may be arranged to withdraw each bolt alter-
nately. The air supply from the lid passes through a space in the
hollow door, and then to the fire. The doors are hinged in an inclined
position so as (when partly shut) to close by their own gravity.
Secondly. My Invention relates to means for regulating the supply of
air to the solid incandescent part of the fuel through the grate bars
without interfering with the intermittent supply above the grate bars for
consuming the smoke and combustible gases, such supply of air through
the grate bars being made to depend upon the pressure of the steam, the
supply of air being diminished or shut off when the pressure of the
steam is in excess of that fixed upon, and turned fully on when the
pressure returns to the maximum. By this mode of "damping" the fire

page_text: the full force of the chimney draught is maintained, and the smoke and
combustible gases are consumed by the air admitted above the fire-bars,
even when the supply of air through the fire-bars is entirely shut off.
By the ordinary mode of "damping" the chimney draught acting upon
the fire is diminished, and a large part of the gases generated in the
furnace pass up the chimney unburnt. This part of my Invention
consists in applying frames to the front of the ash-pit of the furnace, so
as to close it in, which frames are hinged to turn away when required
to allow ashes to be removed, and they are filled with pivotted plates or
boards to open and close like a Venetian blind (or any other valvular
arrangement may be used), and in connecting the pivotted plates or
valves by rods and levers with one side of an elastic diaphragm having
the pressure of the steam in the boiler acting on the other side. The
diaphragm is weighted by a lever combined with a weight lover arm
placed at an angle, or by a weight and spring combined.
Thirdly. My Invention relates to the furnaces of vertical boilers, and
consists in forming a partition or deflector in the fire-box of fire-brick
material above the fire, or it may be a hollow metal partition in an
inclined position in communication with the water space of the boiler.
This partition causes all the gases from the burning fuel to come near to
the furnace door before passing to the flue above the partition, so
that air admitted at the fire-door by suitable apparatus, similar to that
described in the Specification of the said Letters Patent granted to me,
as aforesaid, will mix with and ignite the unconsumed gases.
Fourthly. My Invention relates to those fire-bars which can be
" rocked " to break up the clinkers and discharge ashes, and thus keep
the air spaces in and between the grate bars open. Such grate bars have
hitherto been made with two or more rows of parallel slots in a straight
line for air, but such bars are very liable to break from unequal
expansion and contraction; and this part of my Invention consists in
making the bars zig-zagged or "wavy" laterally, so as to bend and give
way more easily to unequal expansion and contraction. This part of my
Invention also further consists in rocking the bars by a lever (on a
fixed stud or fulcrum) having a socket for a lever handle, which is
passed through a slotted hole that limits the length of the rocking move-
ment, the lever handle being formed (upon the principle of a butler's tap
key), so that it can only be inserted and withdrawn from the socket in

page_text: the central position when the surfaces of the rocking bars are in thè
same line.
A key lever working in and through a keyhole may be used in place
of the socketed lever and lever handle above described.
Fig. 1 is a front view of part of the end of a boiler; and Fig. 2, a
longitudinal section thereof, illustrating the first and second parts of my
Invention. a is the boiler; a', the casting for the doors and other
parts fixed to the front of the furnace; a³ is the dead plate; and a³,
the fire-bars. b are two fire-doors hinged at 6, and 62 is a platé
carried on studs at the inside of the doors; 63, eye at the upper part
of each door; 6' is a vertical sliding bolt, which can enter the eye b³
(there being one bolt for each door). c is a lid hinged at c¹; when open
it allows the air to pass to the furnace, as shown by the arrows. There
are two projections c² on each lid (one for each door), and each pro-
jection acts upon a pin in the sliding bolt 6 for each door, and
withdraws it from the eye (63) when the lid shuts, thus leaving the
doors) 6 at liberty to be opened. There is a projection 6 from each
door, which comes under the lid c, so that whichever door is opened the
air lid c will be opened at the same time. The air lid c is connected by
a chain c³ with a weighted lever c', which draws up the slack chain, so
that the lid is only allowed to close at the speed fixed upon, and as
regulated by the apparatus (2) herein-before referred to, as described in
the Specification of my Patent, No. 19, A.D. 1867.
d is a frame covering the mouth of the ash place hinged to the
casting at d³, so as to be turned up when required. In this frame d á
series of thin metal plates d are hinged to open and close like louvre
boards; each hinged plate has a projection that is jointed with a bar
or handle d', by acting upon which all the louvre plates are simul-
taneously opened or closed. This bar d' is connected by a chain d³ with
an arm e¹ from a shaft e in front of the boiler, as shown, which shaft is
acted upon by a diaphragm described as follows:-fis a box fixed in any
suitable position, and connected with the steam in the boiler by a
pipe f; the steam acts upon the under side of an elastic diaphragm ƒ³,
which is connected with a sliding centre pin fs, guided as shewn in
section in Fig. 2. The upper end of the pin acts upon a lever f*, having
its fulcrum f³ on a bracket secured to the box, and the lever has pressurc
put upon it to resist a part of the pressure of the steam acting upon the

page_text: diaphragm by a spring g coiled round a stud g¹ secured to the box f, one
end of the spring acting against the lever f*, and the other end against a
regulating screw 93 on the stud, by which screw the counteracting
pressure may be adjusted as required; the lever f' is connected by a
rod f* with a second lever f³, leaving its fulcrum on a bracket secured
to the box at f", which has an adjustable weight that serves in con-
junction with the spring (9) to counteract the pressure of the steam. The
lever is connected by an adjustable rod f³ with a lever f' on the
end of the shaft e. With this arrangement, if the steam pressure in
the boiler increases above that fixed upon, the louvres are closed, and
vice versa.
Fig. 3 is a section of a vertical boiler; and Fig. 4, a plan section,
illustrating the 3rd part of my Invention. a is the deflector, which
may be formed of fire-resisting material, or of metal communicating
with the water space of the boiler (6); c are the grate bars; d, the
furnace door.
Fig. 5 is a plan, Fig. 6 an end view, Fig. 7 a front view, and
Fig. 8 a longitudinal section illustrating the fourth part of my
Invention. a, the sides of the furnace; b, side bars secured to the sides
to carry the pivots c³ of the rocking bars c, which are made as shewn in
plan; Fig. 6 shews a side view of the bars; and Fig. 8, the bars in cross
section. Each bar has a pin o³ from its under side that passes through a
hole in a bar c³ extending under all the bars c. The end of the bar c³
is jointed with a bell crank lever d, having its fulcrum on the under
side of the dead plate (e); one arm of this lever has a socket for a
handle, which is inserted through a slot e¹ in a projection formed on the
dead plate, and this slot limits the extent of rocking movement to be
given to the bars. The handle has an enlarged part upon it, so that it
can only be inserted through the slot into the socket, and withdrawn
therefrom when the bars c are in the level position, there being a corre-
sponding enlargement in the centre of the slot.
I have now particularly described the nature of my said Invention,
and the mode of carrying the same into effect, and claim as my
Invention,―
Firstly. The system or mode of arranging the furnace doors of steam
boilers, so as to be fired alternately, and combining therewith mechanism
and arrangements for regulating the supply of air above the fire-

page_text: bars, substantially as herein-before described and illustrated by the
Drawings.
Secondly. The system or mode of regulating the supply of air to the
under side of the fire-bars of steam boiler furnaces according to the
pressure of steam, substantially as herein-before described and illustrated
by the Drawings.
Thirdly. The combination of a deflector with vertical steam boilers,
substantially as herein-before described and illustrated by the Drawings.
Fourthly. The improved rocking fire-bars and the handle combined
with the slot in the projection from the "dead plates," substantially as
herein-before described and illustrated by the Drawings.
In witness whereof, I, the said Joseph Knowles Broadbent, have
hereunto set my hand and seal, this Twenty-seventh day of
February, in the year of our Lord One thousand eight hundred
and seventy-three.
JOSEPH K. BROADBENT. (L.S.)