IMPROVEMENTS IN KILNS
Year: 1880

page_text: LETTERS PATENT to George William Hargreaves Brogden and Edward Casper,
both of King William Street, in the City of London, for an Invention of
"IMPROVEMENTS IN KILNS."
PROVISIONAL SPECIFICATION left by the said George William Hargreaves
Brogden and Edward Casper at the Office of the Commissioners of Patents on
the 14th February 1880.
GEORGE WILLIAM HARGREAVES BROGDEN and EDWARD CASPER, both of King
William Street, in the City of London. "IMPROVEMENTS IN KILNS."
.
Among the many efforts heretofore made to simplify the construction of kilns so
as to diminish the quantity of fuel required, and the amount of labour necessary, the
nost nearly approaching the object in view is on kilns of a tunnel shape.
The objection however to the practical utility of this class of kiln are the
following:-
=
During the time necessary for the introduction and withdrawal of the trucks
containing the bricks or other plastic forms to be burnt a rush of cold air is
permitted to enter.
From the earliest times it has been recognised that the admission of external air
into the kiln wherein plastic material is undergoing the process of transformation
into ceramic or other products is prejudicial to the commercial value of the articles
to be manufactured.
The kilns of tunnel form or construction heretofore made permit a draught of
cold air to traverse them during a time more or less prolonged, and thus diminish
the heat obtained at great expense, besides causing the deterioration of their
contents.
We have invented a simple means of remedying this defect. We construct a
prolongation of the ordinary tunnel kiln, and of a length of sufficient (say), for two
or three trucks, and we fix at the ends of such prolongation a pair of doors, which
doors are made so as to reach to the ground, so that when they are allowed to
descend they absolutely exclude external air from the kiln.
In order to obtain all the results possible from the heat in the kiln, we utilize
the space between the exterior and interior doors of the inlet end of the kiln as a
drying chamber, and in order to render this chamber of the highest use we make
apertures, preferably in the lower part of the interior door, which apertures are so

page_text: contrived as to be capable of being covered or uncovered according as the work to
be done renders it necessary. These holes when uncovered admit the heat from the
kiln itself into this exterior or drying chamber, and by partially closing or
diminishing the number of these holes, we regulate the heat so admitted in such a
way as to make our drying chamber more or less hot, as the condition of the
substances renders necessary. Other dampers than those above described may
be applied to the flues in order to regulate and direct the draught as may be
required.
In the centre or other suitable part of the drying chamber we construct a flue
which communicates with the chimney, and by the draught thus created wo draw
off and convey into the chimney the steam or stive proceeding from the bricks or
other substances.
It is of the utmost importance that the operation of closing and opening these
doors be performed expeditiously and completely. For this purpose we adopt the
following contrivance or contrivances:-We balance each pair of doors with a
weight, and we connect each pair of doors by an apparatus connected with power,
so that by the mere shifting of a clutch or its equivalent we raise or lower each
pair of doors at will, or otherwise, as may be required.
-
On
At the present time the pair of doors which we call the interior doors allow a
draught of cold air to enter from the top into the kiln to the detriment of the
material to be treated. In order to prevent this current of air, the doors pass
through an iron framing of a channel section, which frame is filled with sand.
the top of this door above the channel we attach a frame of angle iron made so as
to fit into the channel before described, so that when the door descends the angle
iron presses down and into the sand and closes the aperture, and so a tight joint is
made.
In order to regulate the position of the wagon in the interior of the kiln, and
to prevent their being driven behind the interior door, which would necessitate the
labour of readjustment, we provide on the rails suitable blocks or stops which are
operated by means of rods and lovers worked from the outside, preferably the inlet
end, so that we enable the attendant to block or stop the wagons at the desired
point, and to release them when necessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George William Hargreaves Brogden and Edward Casper in the
Great Seal Patent Office on the 14th August 1880.
GEORGE WILLIAM HARGREAVES BROGDEN and EDWARD CASPER, both of King
William Street, in the City of London. "IMPROVEMENTS IN KILNS."
Among the many efforts heretofore made to simplify the construction of kilns so
as to diminish the quantity of fuel required, and the amount of labour necessary,
the most nearly approaching the object in view is the construction of kilns of a
tunnel shape.
The objections however to the practical utility of this class of kiln are the
following:
During the time necessary for the introduction and withdrawal of the trucks
containing the bricks or other forms or substances, a rush of air is permitted to
enter at one end of the kiln, and to pass through the whole mass in course of
treatment or transformation, passing out at the opposite end, thus creating a cold
blast.
From the earliest times it has been recognised that the admission of external or
cold air into the kiln wherein material is undergoing the process of transformation
into ceramic or other products is prejudicial to the commercial value of the articles
to be manufactured.
The kilns of tunnel form or construction heretofore made permit a draught of
cold air to traverse them during a time, more or less prolonged, and thus to
diminish the heat obtained at great expense, besides causing general deterioration
of contents.
We have invented a simple means of remedying this defect. We construct at
the exit end of the ordinary tunnel kiln a prolongation of a length of sufficient
(say) for two or three trucks, and we fix at the end of such prolongation a door or
pair of doors, which are made so as to reach to the ground, so that when they are
allowed to descend they absolutely exclude external air from the kiln.
In order to obtain all the results possible from the heat in the kiln, we utilize the
space between the exterior and interior doors of the inlet end of the kiln as a
drying chamber; and in order to render this chamber of the highest use we make
apertures, preferably in the lower part of the interior door, which apertures are so
contrived as to be capable of being covered or uncovered according as the work to
be done renders necessary. These holes when uncovered admit the heat from the
kiln itself into this exterior or drying chamber, and by partially closing or
diminishing the number of these holes, we regulate the heat so admitted in such n
way as to make our drying chamber more or less hot, as the condition of the
substances renders necessary. Other dampers than those above described may
be applied to the flues in order to regulate and direct the draught as may be
required.
In the centre or other suitable part of the drying chamber we construct a fluo
which communicates with the chimney, and by the draught thus created we draw
off and convey into the chimney the steam or stive proceeding from the bricks or
other substances.
It is of the utmost importance that the operations of closing and opening these
doors be performed. expeditiously and completely; for this purpose we adopt the
following contrivance or contrivances:-We balance each door or pair of doors with
a counter weight, and we connect each door or pair of doors to an apparatus
connected with power, so that by the mero shifting of a clutch or its equivalent we
raiso or lower the door or pair of doors as may be required.
At the present time the door or pair of doors which we call the interior doors
allow a draught of cold air to enter from the top into the kiln to the detriment of

page_text: the material to be treated. In order to prevent this current of air, the doors used
in our Invention pass through an iron framing of a channel section, which frame is
filled with sand.
On the top of each door above the channel we attach a frame of angle iron made
so as to fit into the channel before described, so that when the door descends the
angle iron presses down and into the sand and closes the aperture, and so a tight
joint is made.
In order to regulate the position of the wagons in the interior of the kiln, and
to prevent their being driven beyond the interior door or pair of doors, which would
necessitate the labour of readjustment, we provide on the rails suitable blocks or
stops which are operated by means of rods and levers worked from the outside,
preferably the inlet end, so that we enable the attendant to block or stop the
wagons at the desired point, and to release them when necessary.
In order that our Invention may be more fully understood we will now describe
the same with reference to the accompanying Sheet of Drawings. Fig. 1 is a
longitudinal section; Figure 14, a part plan, and Figure 2 is a cross section through
the line u, x, y, z, of Figure 5, of a kiln constructed according to our Invention ;
Figure 3 is a side elevation of a similar kiln illustrating one mode according to our
Invention for opening and closing the doors, showing also a stacking shed or
chamber Tin section to which the bricks are fed from the adjoining brick machine;
Figure 4 is a side elevation of another arrangement or modification also constructed
according to our Invention, showing another arrangement for opening and closing
the doors; Figure 5 is a sectional plan, and Figure 6 is a cross section through line
E, F, of Figure 1, the same; Figure 7, Sheet 2, is a vertical cross section of kiln
through line p, q, of Figure 1, showing an arrangement for raising and lowering
the dampers or doors, but drawn on a larger scale than the previous Figures;
Figure 8 is a view of the arrangement for arresting the wagons; Figure 9 is cross
section of same; Figure 10 shews the arrangement for stopping currents of air
between the doors and the sides of the kiln; Figure 11 is front elevation, and
Figure 12 is sectional plan of a door or damper arrangement; Fig. 13 is a vertical
section through the door shown at Fig. 11, and Fig. 14 is a side elevation showing
said door with its slabs in drawn up or open position. Similar letters of reference
refer to like parts in all the Figures.
A is the heated chamber through which the trucks of bricks or other forms pass
previous to going to the furnace; B is the furnace; a and b are the doors for
closing the heated chamber. The door b may be formed with apertures of suitable
size, as shown in Fig. 7, for the admission of heated air from the furnace B, as may
be required for the preliminary drying of the bricks or other plastic forms or
substances; the apertures in the doors are provided with adjustable slides or other
dampers, or they may, as shown in Fig. 7, be of such an arca as has been found
most suitable, or they may be made in parts, such as shown in Figs. 11, 13, and 14,
which parts are separated on raising the chain attached to the upper part, as shown
in Fig. 14. The distance between the parts or slabs b', 6, 63, may be regulated by
inserting pegs in the holes 1, 2, 3, and 4 in the bars b, b, fixed to the bottom
slab b, and the bars b connected to the slab b on the other side; C, C³, arc flues
one on each side of the chamber A and leading to the chimney N, they are
provided with dampers n¹, n¹, as shown for regulating the draught; C² is a flue or
culvert to the drying chambers at uppermost part thereof in communication with
the chamber A by apertures c, c, so arranged as to effectually distribute the hot air,
and to pass away by a flue or culvert to the chimney N; E, E, (Figures 1
and 14) are fuel holes in the chamber B above the fire places D.
In building the kiln we enlarge or diminish the size of the fire places and the
number and size of the top firing holes, or we dispense with one or the other, that
is, with the fireplaces or the firing holes, according to the nature of the goods to be
burnt.
The rails of the kiln decline towards the end G of the kiln, and as beforo stated
we provide a stop R, Fig. 1, which is also shown detached and enlarged in sido

page_text: elevation at Figure 8, and cross section detached at Figure 9, on the rails, so that
the trucks should not go further than desired into the furnace, and fis the rail in
which a gap is formed; R is the stop or filling piece for this gap, it is pivotted at
to the web of the rail f, and at the other end is provided with a jaw f3, which
clips over the projecting wob of the railfand prevents any twist of the piece R;
g is a pin and slot to limit the distance the stop or filling piece R can be raised; his
a cam working with a shaft h' for acting on rail; this cam shaft has a lever h which
is actuated by rods or levers or other means operated preferably from the entering
end of the furnace. The trucks inay be of any well known suitable construction.
By pulling the rod or lever in one direction the filling piece R is raised, and by
pushing the same rod in the contrary direction the filling piece or stop is brought
down flush with the top of the rail, and the trucks can run along same.
The doors a, b, d, and e are raised by a winch through a shaft, or by chains or
rods, or in any other convenient way.
At Figure 3 an arrangement is shown whereby they are raised by a shaft having
drums a, b, d', and e¹ thereon; the said drums are provided with clutch gear, so
that only one or two doors may be raised at one time, as the case may be, and
closed, and then the other drumus locked to the shaft and the other doors raised,
and so on, as may be required for the insertion or withdrawal of the trucks of
bricks.
At Figure 4 another arrangement is shown for raising these doors or dampers,
but in this case each door, or it may be two or three doors, are raised simultaneously
if required by chains or equivalent attached at one end to the door or doors, and at
the other end by connections to a chain or chains passing to drums of a winch,
which drums are provided with clutch gear. At Figure 7, Sheet 2, the arrange-
ment for raising and lowering the doors is by chains passing round a drum and
operated by crank handle.
Figure 10 shows the arrangement before described for preventing the admission
of external air to the interior of the kiln, showing the doors with angle irons of a
double L section, the flanges embedding themselves in sand contained in channels
or troughs on each side of the door, such as a; 8, 8, are holes for supplying sand
to the channels r, shown in Figures 3, 4, and 7.
In case of an accident of any kind there is no convenient means of access to
the goods under treatment in tunnel kilns as heretofore constructed.
m, Figures 1, 2, 6, and 7 shows a passage or space formed under the wagons and
between the rails for a workman to enter and get under the wagons or trucks
when necessary to do so, and by this provision it is not necessary to remove the
wagons from the tunnel, as heretofore.
The kiln being in operation, and the portions B and A being filled with trucks,
the chamber G being empty, the doors e and a are lowered to the ground, then the
doors d and b are raised, the stop at R is adjusted, and the whole of the trucks are
advanced the length of one truck by means of the chain t. The stop R is raised so
as to prevent the over running of the next truck. The doors d and bare lowered
to the edge of the trucks. The door a is raised, and a truck of green bricks is
then introduced into the preliminary drying chamber A and coupled to the other
trucks; the door d is then lowered on to the edge of the truck. The truck or
trucks of burnt bricks now in the chamber G can be cooled down by gradually
raising the door e and withdrawn. The flue C in the centre or other suitable part
of the drying chamber communicates as stated with the chimney N, and by the
draught thus created we draw off and convey into the chimney the steam or stive
proceeding from the bricks or other goods; the roof of the preparatory chamber A
is made higher than the kiln proper, so that the steam does not seek to enter the
kiln itself, but is carried off to the stack by the flue C².
When the bricks enter the kiln proper they are capable of supporting the
regularly increased temperature, which fits them for presentation to the vitryfying
heat, which thus acts upon them evenly throughout their entire substance. For
semi plastic bricks too soft to bear more than their own weight, we build laterally

page_text: with the tunnel kiln an annexe M, as shown in dotted lines at Figure 5. This
annexe is of an interior section similar to that of the drying chamber A, to which
latter the trucks are conveyed one by one from the annexe M by means of a
traverser.
The hot air after having passed through all the bricks in the chamber B is by
the damper O admitted to the annexe M, and by placing the bricks therein we
obviate all necessity for a drying floor.
In this annexe, which is of a suitable temperature, the green bricks remain until
they are ready to enter the preparatory chamber A.
In the tunnel kiln with our annexe and our improvements the vitrefaction of the
clay is perfect, because it is effected by exact and properly timed degrees.
Each stage is under the eye of the brickmaker, and can be modified to suit the
circumstances of each case.
Having now described the nature of our said Invention and in what manner the
the same is to be performed, we declare that tunnel kilns with waggons in same for
carrying the forms to be burnt are known, and we therefore lay no claim
whatever to such kilns and waggons when taken alone or separately, except as
hereafter claimed in combination with other devices, but we claim as our
Improvements in Kilns,"
21
First. In tunnel kilns, or in combination therewith, the application of a
preparatory drying chamber, such as A, with or without the annexe M at one
end of the kiln for carrying off the heated vapours or steam, and a cooling
chamber, such as G, at the opposite end for preventing the too sudden cooling and
consequent cracking of the goods, substantially as described and shown.
Second. The fitting to the inner, ends of such drying and cooling chambers
sliding doors or dampers, which may be provided with apertures adjustable or not,
the said doors or dampers being fitted and operated substantially in manner and
for purposes hereinbefore set forth.
Third. In combination with tunnel kilns having end chambers, such as A and C,
the employment of the firing or feeding holes E arranged as set forth, and the
passage beneath for going under the waggons, all substantially as herein before
described and shown.
Fourth. In combination with tunnel kilns, the apparatus or appliance for
arresting the waggons and for regulating their position therein, substantially as
described and shown.
"
In witness whereof, we, the said George William Hargreaves Brogden and
Edward Casper, have hereunto set our hands and seals, this Seventh day
of August, in the year of our Lord One thousand eight hundred and
GEO. W. H. BROGDEN. (L.S.) 4
EDWARD CASPER.
(L.S.)