Improvements in Lime-kilns.
Year: 1893

page_text: Date of Application, 2nd Nov., 1893
Complete Specification Left, 2nd Aug., 1894-Accepted, 8th Sept., 1894
Improvements in Lime-kilns.
A communication from abroad by QUAREZ FRÉRES, of Villeneuve-sur-Verberie,
Oise, France, Engineers.
I, BERNARD DAWSON of York House, Malvern Link, in the County of
Worcester, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object to obviate or mitigate the disadvantages
experienced in working gas-heated lime-kilns fed by means of a series of coal
gas-producers on Siemens or other systems, or by coke gas-producers. In the first
mentioned arrangement the gas-producers have usually been placed as near as
possible to the kiln;. whilst in the second case the gas-producers have been
comprised in the mass of masonry forming the base of the kiln.
The arrangement of such furnaces has been difficult and the composition of the
gas and its calorific power have been subject to variations. The working of the
gas-producers and the out-put of the combustible gas. also have depended on
the draught of the kiln, on the state of the atmosphere, on the direction of the
wind, and on the attention of the workman, and irregularity in the burning of the
lime has been found to result.
Moreover, a kiln with gas-producers in the base besides presenting difficulties in
construction is liable to require frequent and somewhat costly repairs.
Now although it has been endeavoured to give lime-kilns a rectangular or
elliptical section, only kilns of circular section have as far as I know come into
practical operation, and even these it has not been found practicable to construct
of large diameter; besides which their power has been limited because the
combustible gas, arriving in the kiln only through holes placed at the
circumference, has exercised its calorific action only over a comparatively small
radius.
°
Now according to this invention in order to obviate or mitigate the disadvantages
above indicated, to render unnecessary the restriction to a particular kind of fuel
such as coke or anthracite the price of which is high; to produce lime free from
admixture of ash derived from the fuel; and to avoid the introduction into the kiln
of an excess of air and to ensure the production (in the case of sugar works) of a
gas rich in carbonic acid specially suitable for carbonating operations there is
applied to a lime kiln a single separate gas-producer (preferably a water bottom
gas producer) blown by a jet of steam, and which is made to supply under pressure
gas enriched by a large proportion of hydrogen.
The distribution of the combustible gas is effected by means of two series of burners
the upper of which terminate around the shaft or body of the kiln around the
limestone therein. The lower burners are designed to calcine the stone situate in
the middle of the kiln and are arranged around a central hole or extension forming
a kind of second kiln of smaller diameter at the bottom of the principal shaft.
underground passage permits of the removal of the lime from the furnace below
this central hole or second kiln and affords access for the air necessary to support
combustion.
An
The gas is distributed by conduits made in sections, controlled by a regulating-
valve. The orifice through which the gas to each burner passes is or may be
regulated by means of a valve damper or slide; and the air is distributed by means

page_text: of special orifices arranged in the masonry below each gas-inlet and furnished with
means for enabling the access of air to be moderated at will.
Thus it will be understood that the air is not admitted by leaving more or less
open the doors that serve for discharging the lime which is an arrangement that is
open to objection because the gas-burners located immediately above the discharge
doors receive an excess of air, especially on the side facing the wind, whilst the
gas brought by the other burners do not meet with sufficient air to produce
complete combustion. The kiln according to this invention is furnished with
discharge-doors which close hermetically and each of the air inlets below the
respective gas burners leads from the exterior and is furnished with an obturator or
valve to enable the entry of air to be moderated.
Dated, this 2nd day of November 1893.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
A communication from abroad by QUAREZ FRERES, of Villeneuve-sur-Verberie,.
Oise, France, Engineers.
I, BERNARD DAWSON, of York House, Malvern Link, in the County of
Worcester, 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 has for its object to obviate or mitigate the disadvantages
experienced in working gas-heated lime-kilns fed by means of a series of coal
gas-producers on the Siemens or other systems, or by coke gas-producers. In
the first mentioned arrangement the gas-producers have usually been placed as
near as possible to the kiln; whilst in the second case the gas-producers have been
comprised in the mass of masonry forming the base of the kiln.
The management of such furnaces has been difficult, and the composition of the
gas, and its calorific power, have been subject to variations. The working of the
gas-producers and the out-put of the combustible gas also have depended on
the draught of the kiln, on the state of the atmosphere, on the direction of the
wind, and on the attention of the workman, and irregularity in the burning of the
lime has been found to result. Mcreover, a kiln with gas-producers in the base,
besides presenting difficulties in construction, is liable to require frequent and
somewhat costly repairs.
Now although it has been endeavoured to give lime-kilns a rectangular or
elliptical section, only kilns of circular section have, so far as I know, come into
practical operation, and even these it has not been found practicable to construct
of large diameter; besides which their power has been limited because the com-
bustible gas, arriving in the kiln only through holes placed at the circumference,
has exercised its calorific action only over a comparatively small area.
Now, according to this invention, in order to obviate or mitigate the disadvantages
above indicated, to render unnecessary the restriction to a particular kind of fuel,
such as coke or anthracite the price of which is high; to produce lime free from
admixture of ash derived from the fuel; to avoid the introduction into the kiln of
an excess of air; and to ensure the production (in the case of sugar works) of a gas
rich in carbonic acid, specially suitable for carbonating operations, there is employed
with a lime kiln a single separate gas-producer (preferably a water bottom gas-
producer) blown by a jet of steam, and which is made to supply under pressure gas
enriched by a large proportion of hydrogen.

page_text: The distribution of the combustible gas is effected by means of two series of
burners the upper of which terminate around the shaft or body of the kiln around
the limestone therein. The lower burners are designed to calcine the stone situate
in the middle of the kiln and are arranged around a central hole or extension
forming a kind of second kiln of smaller diameter at the bottom of the principal
shaft. An underground passage permits of the removal of the lime from the
furnace below. this central hole or second kiln and affords access for the air
necessary to support combustion.
The gas is distributed by conduits made in sections each controlled by a
regulating-valve. The orifice through which the gas to each burner passes, is or
may be regulated by means of a valve, damper or slide; and the air is distributed
by means of special orifices arranged in the masonry below each gas-inlet and
furnished with means for enabling the access of air to be regulated at will.
Thus it will be understood that the air is not admitted by leaving more or less
open the doors that serve for discharging the lime, which is an arrangement that is
open to objection because the gas-burners located immediately above the discharge
doors receive an excess of air, especially on the side facing the wind, whilst the gas
brought by the other burners do not meet with sufficient air to produce complete
combustion. The kiln according to this invention is furnished with discharge-
doors which close hermetically, and each of the air inlets below the respective gas
burners leads from the exterior and is furnished with a valve to enable the entry of
air to be regulated.
In the accompanying illustrative drawings,
Fig. 1 is a vertical section on the line A B C of Fig. 3 i and
Fig. 2 is a part vertical section, on the line D E E B of Fig. 3, showing a lime
kiln constructed according to this invention.
Fig. 3 is a sectional plan of the kiln, the lower left and right hand quarters of
the figure being sections on the lines F G and H I respectively of. Fig. 1, and the
upper left and right hand quarters of the figure being sections on the lines K L
and M N respectively of Fig. 2.
1 is the main gas conduit or flue provided with normally closed man holes 1ª
and serving to conduct combustible gas to the interior of the kiln 2 from a gas
producer 15. This gas producer, which is preferably of the type herein before
referred to, is arranged at some distance from the kiln and is provided with a
closed grate, and air is blown into it by means of a steam jet whereby the
resulting gas will be delivered to the kiln under pressure, and will contain a
large proportion of hydrogen, resulting from the decomposition of the steam, so
that it will have a high calorific value. In such a gas producer fuel of an inferior
quality can be readily burnt. 3 are the upper gas burners consisting of ports
or passages arranged in an annular series and terminating at their inner ends
around the shaft or body of the kiln. 4 are the lower burners arranged at
opposite sides of the wall of a central hole or upward extension 5 that forms a
kind of second kiln of smaller diameter at the bottom of the principal shaft
with which it is connected by the arches or roofs 5* of underground passages 5b
by which access is gained to doors 5 that normally close discharge openings in
the lower portion of the said second kiln. The ports or passages constituting
the upper burners 3 are connected by vertical passages 3ª with cursed or
segmental gas supply conduits or sections 3b of which there are four, each
common to a group of burners and each connected with the main gas flue 1
by a passage 3* controlled by a regulating valve 3°. By this arrangement the
flow of gas to the several conduits or sections 3 can be independently controlled.
Each upper burner is provided with a laterally adjustable damper by which the
flow of gas through the corresponding vertical passage 3* can be regulated.
The lower burners 4 are arranged in pairs each connected with a common
conduit 4 the communication between which and the main gas flue 1 is con-
trolled by a separate regulating valve 4°. 6 and 7 are ports or passages
arranged in the masonry of the kiln below and serving to supply air for the

page_text: combustion of the gas escaping from the upper and lower burners 3 and 4 below
which they are respectively placed the brickwork around 5 being cut away
opposite the air ports 6 so as to give an upward direction to the air issuing
therefrom. The air ports or passages communicate at their outer ends with the
xternal atmosphere and are, or may be, each provided at such outer end with
a suitable valve, not shown, for enabling the access of air to be controlled to
suit requirement. The shaft or body of the kiln is provided at its lower end
with lateral discharging openings 8 which, for the reason hereinbefore stated,
are normally hermetically closed by doors 8a. At its upper end the shaft or
body of the kiln is provided with a central charging opening 9 for limestone
and with lateral gas exit ports 10 that communicate by an annular passage 10*
with a lateral gas outlet passage 10°. 11 are sight or poking holes normally
closed by removable plugs.
Q
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is :-
1. A lime kiln combined with a separate gas producer and constructed with an
upper series of burners which terminate around the shaft or body of the kiln and
the limestone therein, with a lower series of burners situate in the middle of the
kiln around a central hole or extension forming a second kiln of smaller diameter
at the bottom of the principal shaft, and with suitable air inlets for the respective
burners, the said gas producer being blown with steam and arranged to deliver gas
under pressure to the said burners, substantially as herein described for the purposes
specified.
2. A lime kiln of the kind specified in the preceding claim in which the burners
are supplied with gas from independent conduits the communication between each
of which and the main gas conduit or flue is controlled by a separate regulating
valve substantially as herein described for the purpose specified.
3. A lime kiln of the kind specified in Claim 1 having its discharge doors
arranged to be hermetically closed and provided with air supplying passages
arranged in the masonry of the kiln below the upper and lower gas inlets and
furnished at their outer ends, where they communicate with the external atmosphere,
with means for enabling the access of air to be moderated at will, substantially as
herein described for the purpose specified.
4. A lime kiln with separate gas producer constructed arranged and operating
substantially as described and shown.
Dated this 2nd day of August 1894.
BERNARD DAWSON.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.