Improvements in Continuous or Running Kilns for Burning Lime, Cement, and other similar Materials.
Year: 1894

page_text: Date of Application, 15th May, 1894
Complete Specification Left, 13th Feb, 1895-Accepted, 23rd Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements in Continuous or Running Kilns for Burning Lime,
Cement, and other similar Materials.
I, ANTOINE BAUCHÈRE Engineer, Works Manager of La Société des Ciments
François of Boulogne sur Mer in the Republic of France do hereby declare the
nature of my invention to be as follows:-
:--
This invention relates to improvements in continuous or running kilos, employed
in burning lime, native or Portland cement or other similar materials by a con-
tinuous process.
The main objects of the invention are to burn the materials named, in a con-
tinuous, even and uniform manner and to prevent the fuel from "catching" or
adhering to the walls of the kiln to ensure the complete and continuous combustion
of the gases, so as to avoid interruptions, even while the kiln is being charged
with material; and to utilize the heat, which has hitherto been lost in the process,
and in making cement, to provide for the continuous and automatic breaking up
of the burnt material, prior to its removal from the kiln.
To enable the materials to be burnt in a continuous, even, and uniform manner
it is necessary that a practically constant temperature should be maintained in
or section of the kiln where the actual burning takes place.
the "zone
.
"
For this purpose there are provided two gas inlets, one of which admits a con-
tinuous supply of gas and is situated above the section or zone, wherein the gas is
consumed, while the other, through which gas is admitted intermittently, is
arranged in the upper part of a conical charging head or dome surmounting
the kiln.
The continuous gas inlet, which is separated from the charging or feeding orifice
by the material contained in the charging dome, is permanently connected with
the draught flues, and so long as the dampers of the chimney are properly con-
trolled, this gas inlet will, whenever the kiln is charged or "served" draw in all
the gases rising from the kiln, thereby maintaining the lime-burning zone in a
condition of constant depression, while securing at the same time the admission
of the regular supply of air which is necessary to assist combustion.
The intermittent gas inlet, which closes automatically whenever the charging
dome is opened, enables the kiln to be charged or served, without the necessity
of forcing back the gases or admitting cold air. Whilst, therefore, the material
to be burnt is fed, and no matter how long the feeding operation may last, no
alteration whatever is brought about thereby in the general behaviour of the kiln.
To prevent the fuel from "catching or hanging on to the walls of the kiln, it
is necessary that the kiln should be charged or served in such a manner, that the
fuel, which the very charging operation serves to distribute, or to spread out from
the centre towards the periphery of the kiln, is moved up to such periphery only
in such quantities as are just sufficient to cause the materials to be burnt to the
predetermined maximum extent, by contact with the said walls of the kiln. And it
is further necessary that the material to be burnt should be fed to the kiln in such
a manner, that in meeting the walls thereof within the burning zone, it may exercise
but a feeble pressure, so that the softened material in contact with the outer casing
of the kiln is not pressed down or caused to settle and the fuel cannot adhere to
the walls.

page_text: For this purpose, a break or recess is provided between the charging cone and
the body of the kiln, whereby the material to be burnt is caused to drop into the
kiln as though slipping or sliding down an incline so that the thin layer of fuel is,
as it were encased in such material and consequently kept out of contact with the
walls of the kiln.
To obtain a complete and continuous combustion of the gases, it is necessary to
maintain a constant temperature in the gas combustion chamber.
For this purpose, an arrangement of flues is employed, to allow heated air only
to be admitted into the said combustion chamber even while the kiln is being
charged or served, such air being allowed to mix properly with the gases,, and also
to permit the gases entering at the top of the kiln, to be heated as nearly as possible
to the temperature of the comparatively hot gases which are admitted in the
burning zone.
To ensure the continuous and automatic breaking up of the burnt material, it is
only necessary to produce unequal expansions in the material, and then to slake th
lime that may be contained in such material.
To effect this, a steam injector is arranged under the grate.
The following is an arrangement of kiln according to this invention but I do not
limit myself to the precise details.
"
The kiln is surmounted by a charging head or dome between which and the top
of the kiln proper there is left an arch-shaped recess or break, which constitutes
the lower, or what is herein termed "the continuous gas inlet. It communicates
with the flues leading to the chimney, both through a vertical channel, and through
ports and a flue which surrounds the charging dome and is connected by a number
of apertures with the said vertical channel.
At the top of the charging dome there is provided the second gus inlet, herein
(described as the upper or "intermittent" gas inlet. It is formed by a circular
flue perforated on the inner side and subdivided into a number of sectors, each
communicating with a conduit or channel opening into a flue which is situated
immediately above the first mentioned flue surrounding the charging dome and,
similarly to the latter, surrounds the charging dome.
This second flue opens
likewise into the aforesaid vertical conduit by means of a series of apertures.
The flue of the lower gas inlet, and the flue of the upper gas inlet are separated
from each other by metal plates. The object of this arrangement is to heat the
gases admitted through the upper inlet so as to raise them to a temperature
practically equal to that of the gases admitted through the lower inlet, which are
naturally hotter than the others, coming as they do, from the combustion zone.
The conduits or ports of the upper gas inlet are each provided with a damper
which is connected by a chain, passing over suitable wheels or pulleys, with the lid
or cover of the charging dome. The dampers and lid, thus connected, are suitably
balanced so as to facilitate the operation of this damper arrangement. The object
of the connection is automatically to close the dampers whenever the lid is removed
in order to admit a batch of material, and also to keep the said dampers open
while the lid remains closed between every two successive chargings of the kiln.
It will thus be seen that the action of the upper gas inlet is intermittent, it only
admitting gas whilst the lid is closed; whereas, when such lid is open, and the
dampers are closed, the gases continue to pass off from the lower continuous inlet
into the chimney, inasmuch as the air which is caused (by the suction, however
slight this may be) to pass through the charging dome prevents the gases from
escaping through the charging or feeding orifice of the kiln, when the damper,
which connects the flues with the chimney, is opened more or less.
Below the flue of the lower gas inlet there are provided conduits or ports,
adapted to receive and heat the external air, and to send it through the aforesaid
vertical passage.
Other conduits are provided for the purpose of bringing the heated air opposite
to the orifices of the flue of the lower gas inlet; and these conduits through the
medium of suitable branches also impart to the heated air such a direction as to

page_text: cause it to meet at right angles, the gas jet or current passing through the flue
towards the chimney.
Under the grate of the kiln there are provided a perforated pipe or perforated
pipes adapted to inject into the mass under treatment a number of thin currents of
steam which steam may be generated in a small boiler embedded in the thickness of
the material of which the kiln is made, and in the vicinity of the zone of combustion
or a separate boiler may be used for this purpose. The pipe or pipes under the
grate are connected with the boiler by suitable tubing. As before stated, the
object of these steam jets is to break up the burnt material before it is removed
from the kiln.
The break above referred to serves not only as a lower permanently acting gas
port, as stated, but also as a means for causing the material fed to the kiln for
burning, to descend or slip down in the form of a slope, and in so doing, to encase
or envelop the layer of fuel as it were and prevent its contact with the walls of
the kiln.
Dated this 15th day of May 1804
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, Agents.
Improvements in Continuous or Running Kilns for Burning Lime,
Cement, and other similar Materials.
I. ANTOINE BAUCHERE, Works Manager of La Société des Ciments, Français,
of Boulogne-sur-Mer in the Republic of France, Engineer, 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:
―
This invention relates to improvements in continuous or "running" kilns
employed in burning lime, native or Portland cement or other similar materials by
a continuous process.
The main objects of the invention are: to burn the materials named, in a
continuous, even and uniform manner and to prevent the fuel from catching or
adhering to the walls of the kiln to ensure the complete and continuous combustion
of the gases, so as to avoid interruptions, even while the kiln is being charged with
material, and to utilize the heat, which has hitherto been lost in the process; and
in making cement, to provide for the continuous and automatic breaking up of the
burnt material, prior to its removal from the kiln.
To enable the materials to be burnt in a continuous, even and uniform manner,
it is necessary that a practically constant temperature should be maintained in the
zone or section of the kiln where the actual burning takes place. For this
purpose there are provided two gas inlets, one of which admits a continuous
supply of gas and is situated above the section or zone, wherein the gas is
consumed, while the othor, through which gas is admitted intermittently, is
arranged in the upper part of a conical charging head or dome surmounting
the kiln.
The continuous gas inlet, which is separated from the charging or feeding
orifice by the material contained in the charging dome, is permanently connected
with the draught flues and so long as the dampers of the chimney are properly
controlled, this gas inlet will, whenever the kiln is charged or "served," draw
in all the gases rising from the kiln, thereby relieving the pressure in the lime-
burning zone, while securing at the same time the admission of the regular
supply of air which is necessary to assist combustion.
The intermittent gas inlet, which closes automatically whenever the charging
dome is opened, enables the kiln to be charged or served, without the necessity

page_text: of forcing back the gases or admitting cold air. Whilst, therefore, the material
to be burnt is fed, and no matter how long the feeding operation may last,
no alteration whatever is brought about thereby in the general behaviour of
the kiln.
To prevent the fuel from catching or hanging on to the walls of the kiln, the
kiln should be charged or served in such a manner, that the fuel, which the, very
charging operation serves to distribute, or to spread out from the centre towards
the periphery of the kiln, is moved up to such periphery only in such quantities as
are just sufficient to cause the materials to be burnt to the predetermined maximum
extent, by contact with the said walls of the kiln. And it is further necessary that
the material to be burnt should be fed to the kiln in such a manner, that in meeting
the walls thereof, within the burning zone, it may exercise but a feeble pressure,
so that the softened material in contact with the outer casing of the kiln is not
pressed down or caused to settle and the fuel cannot adhere to the walls.
For this purpose, a break or recess is provided between the charging cone and
the body of the kiln, whereby the material to be burnt is caused to drop into the
kiin as though slipping or sliding down an incline, so that the thin layer of fuel is,
as it were, encased in such material and consequently kept out of contact with the
walls of the kiln.
To obtain a complete and continuous combustion of the gases, it is necessary to
maintain a constant temperature in the gas combustion chamber.
For this purpose, an arrangement of flues is employed, to allow heated air only
to be admitted into the said combustion chamber, even while the kiln is being
charged or served, such air being allowed to mix properly with the gases; and also
to permit the gases, entering at the top of the, kiln, to be heated as nearly as
possible to the temperature of the comparatively hot gases which are admitted in
the burning zone.
To ensure the continuous and automatic breaking up of the burnt material, it is
only necessary to produce unequal expansions in the material, and then to slake the
lime that may be contained in such material.
To effect this, a steam injector is arranged under the grate.
The accompanying drawings illustrate an arrangement of kilu according to this
invention but I do not limit myself to tlie precise details.
Figure 1 is a longitudinal vertical section of the head of a continuous or running
kilu arranged to burn the material at a constantly relieved pressure.
Figure 2 is a vertical section taken at right angles to Figure 1.
Figure 3 is a horizontal section on line 1-2 Figure 1.
Figure 4 is a horizontal section on line 3-4, Figure 2.
Figure 5 is a cross section on line 5-6 Figure 1, showing the gas conduit leading
to the chimney, and
Figure 6 is a vertical section along the line 7-8-9 Figure 2.
The kiln is surmounted by a charging head or dome A between which aud the
top of the kiln proper there is left an arch-shaped recess or break a, which con-
stitutes the lower, or what is herein turned the "continuous "
gas inlet. It
communicates with the flues B leading to the chimney, both through a vertical
channel C, and through ports e, and a flue C which surrounds the charging dome
(Figs. 1. 2. 4 and 6) and is connected by a number of apertures c¹ with the said
vertical channel C.
At the top of the charging dome A there is provided the second gas inlet, herein
described as the upper or "intermittent" gas inlet. It is formed by a circular
flue D perforated on the inner side and subdivided into a number of sectors, each
communicating with a conduit or channel d opening into a flue D', which is situated
immediately above the first mentioned flue C, and similarly to the latter, surrounds
the charging dome. This second flue D' opens likewise into the aforesaid vertical
conduit C by means of a series of apertures d'.
The flue of the lower gas inlet, and the flue D' of the upper gas inlet are
separated from each other by metal plates m. The object of this arrangement is to

page_text: heat the gases admitted through the upper inlet, so as to raise them to a
temperature practically equal to that of the gases admitted through the lower iulet,
which are naturally hotter than the others, coming, as they do, from the combustion
zone of the kiln.
The conduits or ports d, of the upper gas inlet are each provided with a damper r
which is connected by a chain, passing over suitable wheels or pulleys, with the lid
or cover E of the charging dome A.
The dampers and lid, thus connected, are suitably balanced so as to facilitate the
operation of this damper arrangement. The object of the connection is to auto-
matically close the dampers r whenever the lid is removed in order to admit a batch
of material, and also to keep the said dampers open while the lid remains closed
between every two successive chargings of the kilo.
It will thus be seen that the action of the upper gas inlet is, intermittent, it only
admitting gas whilst the lid E is closed; whereas, when such lid is open, and the
dampers are closed, the gases continue to pass off from the lower continuous inlet
into the chimney, inasmuch as the air which is caused by the suction, (however
slight this may be) to pass through the charging dome A prevents the gases from
escaping through the charging or feeding orifice of the kiln, when the damper,
which connects the flues B with the chimney, is opened more or less.
The arrows drawn in full lines shew in the drawings the course taken by the
gases.
Below the flue C¹ there are provided conduits or ports e, adapted to receive and
beat the external air, and to send it through the aforesaid vertical passage C, as
indicated by the dotted arrows.
Other conduits are provided for the purpose of bringing the heated air opposite
to the orifices c' of the flue C₁ of the lower gas inlet; and these conduits, through
the medium of suitable branches g, also impart to the heated air, such a direction as
to cause it to meet at right angles (Fig. 3.) the gas jet or current passing through
the flue B towards the chimney.
Under the grate G (Fig. 2) of the kiln there is provided a perforated pipe
or perforated pipes i adapted to inject into the mass under treatment a number
of thin currents of steam, which steam may be generated in a small boiler F
embedded in the thickness of the material of which the kiln is made, and in the
vicinity of the zone of combustion, or a separate boiler may be used for this
purpose. The pipe or pipes i under the grate G are connected with the boiler
by suitable tubing. As before stated, the object of these steam jets is to break
up the burnt material before it is removed from the kiln.
The break a, above referred to, serves not only as a lower permanently acting
gas port, as stated, but also as a means for causing the material, fed to the kilu
for burning to descend or slip down in the form of a slope, and, in so doing, to
encase or envelop the layer of fuel, as it were, and prevent its contact with the
walls of the kiln.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. In continuous or running kilns for burning lime, natural and Portland cement
and other similar materials, the subdivision of the gas inlets or ports, by means
of a conical charging dome, independent of the kiln proper, and forming a break
above the same, the said subdivision resulting in the formation of a lower gas
inlet or port, deriving its supply of gas from the combustion zone, and of an
upper gas inlet or port, taking the gases above the charge or batch of material
fed to the kiln, the two gas inlets being arranged for either joint or separate
action, according as the kiln is in normal operation, or is being charged with
material, whereby continuity in the operation of the kiln is at all times ensured,
substantially as described.
2. In continuous or running kilns for burning lime, natural and Portland cement

page_text: or other similar materials, the provision of a charging dome, between which ant
the top of the kiln proper, within the zone of combustion, a break is formed in
combination with a lid connected with one or more dampers situated in the flues of
the upper gas inlet, and so arranged that the said dampers automatically close when
the lid is raised, and open when the said lid is closed; all substantially as and
for the purposes hereinbefore described.
::
3. In continuous or running kilns for burning lime, natural or Portland cement
and other similar materials, the arrangement of a charging dome between which
and the top of the kiln proper, in the combustion zone a break is provided adapted
to bring about automatically, as a result of the sinking of the charge, a slipping of
the material to be burnt and the formation of a slope, so that the said material,
thus descending, encases the fuel in the condition of a thin layer, and thereby
prevents the same from coming into contact with the walls of the kiln, being
separated therefrom by a movable case or jacket formed by the material to he
burnt substantially as and for the purposes herein before described.
4. In continuous or running kilns for burning lime, natural and Portland cement
or other similar materials, in combination with the charging dome and the lower
and upper gas inlets, referred to in Claims 1 and 2, the flues enabling the gases
admitted through the upper inlet to be heated, and the gases obtained through the
two inlets to be mixed with heated air by circulation for maintaining a constant
temperature in the combustion chamber and ensuring the entire combustion of the
said gases, substantially as described.
5. In continuous or running kilns, specially adapted for burning natural and
Portland cement, the employment of a steam jet beneath the lower grates of the
said kilns, deriving steam from any suitable boiler, or produced by the heat
generated by the kilns themselves, substantially as and for the purposes hereinbefore
specified.
6. A continuous or running kiln for burning lime, natural and Portland cement
or other similar materials, comprising the combination of the several arrangements
referred to in the preceding claiming clauses and illustrated in the accompanying
drawings.
Dated this 12th day of Dabuuan. 100%
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.