Improvements in Kilns for Burning Limestone and other Materials.
Year: 1897

page_text: Date of Application, 12th Oct., 1897
Complete Specification Left. 12th July. 1898-Accepted, 10th Sept., 1898
PROVISIONAL SPECIFICATION.
Improvements in Kilns for Burning Limestone and other Materials.
We, VINCENT HUGHES, of the Gas Works, Tipton, in the County of Stafford,
Gas Engineer, and EDWARD DONALD NICHOLSON, of Rose Cottage, Llynelys, in the
County of Salop, Lime Works Manager, do hereby declare the nature of this
invention to be as follows:-
This invention relates to kilns, for burning limestone and other materials, in
which the fuel is introduced into the kiln in a gaseous form from a producer, and
in which air is mixed with the gases on their passage from the producer to the
material within the kiln; and the invention comprises improved means by which
the air is heated, combustion effected, and the products of such combustion brought
into contact with the limestone or other material, and the limestone or other
material presented thereto in a manner which ensures a thorough penetration of
the heat through the mass which is at the time in the zone of the kiln where the
greatest intensity of heat is required.
The air flues and combustion chamber may be built in a block of brickwork
which passes across the middle of the kiln leaving a passage way on each side for
the limestone or other material, and the products of combustion be brought into
the mass of the material on each side; and, when this is the case, the block of
brickwork in which the combustion chamber and air flues are formed may be
carried upon an arch or in other manner which leaves a clear space underneath.
The gases from the producer pass along a flue built longitudinally through the
middle of the block of brickwork which crosses the kiln. This flue is immediately
below the combustion chamber which also extends longitudinally through the
block of brickwork, and a number of holes are formed through the top of the gas
flue into the bottom of the combustion chamber, and a number of openings are
formed out from the combustion chamber to the opposite faces of the block of
brickwork. On each side of the gas flue is arranged a set of three flues, the middle
one of each set being a flue for the passage of hot air and it may be other gases
also, from the burnt lime or other material below the level of the underside of
the arch which supports the block of brickwork in which the flues are built, and
the other two flues of each set being secondary air flues, for the passage of air from
outside the kiln to the combustion chamber. Each flue for the hot air from the
burnt material in the kiln passes up from the underside of the arch, near one side
of the kiln, to an outlet opening at the other side of the kiln which leads into a
chimney, and is provided with a number of cross tiles, spaced apart to leave open-
ings between. for the purpose of causing the hot air to distribute itself fairly
evenly throughout the flue and to check its rate of flow to the outlet opening. It
will thus be seen that the hot air from the kiln is drawn through the flues by
the chimney. Each secondary air flue is constructed with longitudinal divisions
through which openings are formed at alternate ends, and the air travels along
all the passages into which the flue is thus divided. The secondary air flues com-
municate at their lower ends, through the wall of the kiln, with the outside atmo-

page_text: sphere, and communicate with one another at their upper ends; and these mues
communicate with the combustion chamber through a number of openings which
are formed through the side of the top passage of the inner flue in position to
come, respectively, opposite to the openings from the gas flue from the producer
into the combustion chamber. The hot air given off from the burnt material below
the level of the bottom of the block of brickwork in which the flues are built,
readily collects and passes up through the flues which are each in position between
two air flues. The hot air from the interior of the kiln is thus utilised in heating
the air on its way to the combustion chamber, and is finally carried off by the
chimney. The air is heated also by the hot lime or other material within the
kiln and by the hot gases on their passage from the producer to the combustion
chamber, and reaching the combustion chamber, consequently at a very high
temperature, and being intimately mixed therein with the producer gas, owing
to the arrangement above described of the gas and air openings into the com-
bustion chamber, ensures a very high temperature in the products of combustion
which pass out from the combustion chamber into the limestone or other material
which is being burnt. The limestone or other material, being divided into two
streams or portions as it passes the openings through which the products of com-
bustion emerge, is more thoroughly exposed to the action of such products than
when dealt with in a mass of greater thickness. The shoulders of the block of
brickwork in which the flues are built are slanted off to prevent the limestone or
other material lodging on the top thereof.
A division wall or walls may, if desired, be carried from the soffit of the arch
to the bottom of the kiln, and also above the block of brickwork in which the
flues are built, to the top of the kiln.
A corresponding arrangement of flues to that above described may be built in
each side of the kiln, with the openings for the passage of the products of com-
bustion arranged in the sides of the kiln; but in such case only one of the sets
of air flues is used at each side of the kiln, and such set is arranged in position
between the fiue from the producer and the inside of the kiln; and such arrange-
ment may be adopted in combination with the arrangement first described, or in
lieu thereof. The lower ends of the flues for the hot air from the interior of the
kiln open into collecting pockets formed in the lining wall of the kiln.
In some cases, an arrangement of flues, such as described in the last preceding
paragraph, may be used at one side of the kiln only, the width of the portion of the
kiln at the front of the Hues, measured from the side at which such flues oecur
to the opposite side, being of suitable dimension to allow of the thorough per
meation of the heat through the limestone or other material being burnt. In this
case, of course, the central arrangement of flues, above described, is dispensed
with.
100-
COMPLETE SPECIFICATION.
Improvements in Kilns for Burning Limestone and other Materials.
We, VINCENT HUGHES, of the Gas Works, Tipton, in the County of Stafford,
Gas Engineer, and EDWARD DONALD NICHOLSON, of Rose Cottage, Llynclys, in the
County of Salop, Lime Works Manager, do hereby declare the nature of this inven-
tion 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 kilus, for burning limestone and other materials, in

page_text: which the fuel is introduced into the kiln in a gaseous form from a producer, and
in which air is mixed with the gases on their passage from the producer to the
material within the kiln; and the invention comprises improved means by which
the air is heated, combustion effected, and the products of such combustion brought
into contact with the limestone or other material, and the limestone or other
material presented thereto in a manner which ensures a thorough penetration of
the heat through the mass which is at the time in the zone of the kiln where the
greatest intensity of heat is required.
A convenient form of the invention is illustrated by Figures 1 to 5, inclusive,
of the drawings herewith, of which Figure 1 is a vertical section taken through
the middle of the kiln and producer, and Figure 2 is a vertical section taken in
the plane indicated by line of Figure 1, such portion only of the vertical height
of the kiln being shewn in each case as is required to illustrate the invention.
Figure 3 is a section taken in the plane indicated by line y y of Figure 2; Figure 4
is a section taken in the plane indicated by line al of Figure 2; and Figure 5
is a sectional plan taken in the plane indicated by line y y of Figure 2. The
arrows indicate the directions of How of the air and gases through the different
flues.
A represents a block of brickwork which passes across the middle of the kiln,
leaving a vertical passage-way B on each side thereof down which the limestone or
other material passes. This block is carried upon a brick arch a, or in other con-
venient manner which leaves a clear space underneath the block.
and
are
The gas from the producer C passes into a flue & which is formed through the
the middle thereof. A com-
length of the block of brickwork A in
bustion chamber D is formed in the block of brickwork A immediately
above the
flue b
gas
passes also longitudinally through such
block of brickwork, and number of openings c
formed through
the crown of the gas flue into the bottom of the combustion chamber D.
Outlet openings d are formed from opposite sides of the upper portion of the com-
bustion chamber D to the opposite faces of the block of brickwork A, through
which the products of combustion from such chamber pass into the limestone or
other material which has just entered the passage-ways B. These openings d
are shewn to enlarge somewhat towards their outer ends. On each side of the
gas flue band within the block of brickwork A is arranged or built a set of three
Hues efc. The middle flue f of these is for the passage from the burnt lime
or other material below the level of the underside of the arch of the air which
has been admitted through the openings in the lower portion of the kiln, in draw-
ing out the burnt material, and which has become greatly heated. The other
two flues e e' of each set are secondary air flues, for the passage of air from out-
side the kiln to the combustion chamber. The portion of the kiln which is
immediately below the arch a communicates, with one end of the bottom of each
flue for the hot air from the burnt material in the kiln, through a flue g, and
the opposite end of the upper part of each such flue communicates through a lue h
with a chimney E, whereby the hot air from the kiln is drawn through the flues
by the chimney draught. Each flue has a number of cross tiles i etc. built therein,
which are spaced apart to leave openings between them as shewn, for the purpose
of causing the hot air to distribute itself fairly evenly throughout the flue and
thus checking its rate of flow to the outlet flue to the chimney. The lower
portion of each secondary air flue is in communication at one end with the outside
air through an opening k, and each such flue is constructed with longitudinal
divisions which are stopped short at alternate ends so that the air traverses
several times the length of the flue before it passes out therefrom. In the case of
each flue e, the air passes from the end of the upper portion thereof which is
opposite to the end at which the inlet opening k is formed, through a flue m, which
passes across the adjacent hot air flue f, into the end of the air flue e which is at
the inner side of such flue f: and in the case of each flue e, the air therefrom, as
also the air which, has passed in thereto from the flue e', passes out through a
i

page_text: nare
number of openings a into the combustion chamber D. These openings
arranged, preferably, to align with, or be opposite to, the openings e from the gas
flue into the combustion chamber. By this arrangement of hot air and external
air flues, the hot air from the interior of the kiln, which readily collects under-
neath the block of brickwork A and passes up through the flues f, is utilized in
heating the air from the outside of the kiln on its way to the combustion chamber,
and finally carried off by the chimney E. The air passing through the flues e c
is heated, also, by the hot lime or other material within the kiln, and by the hot
gases on their passage from the producer through the gas due to the combustion
chamber D, and reaching the combustion chamber, consequently, at a very high
temperature, and being intimately mixed therein with the producer gas, ensures
a very high temperature in the products of combustion which pass out through
the flues into the limestone or other material within the passage-ways B.
The limestone or other material being divided into two streams or portions as
it pusses the openings d, is more thoroughly exposed to the action of such products
than when dealt with in a mass of greater thickness.
The shoulders p of the block of brickwork A are slanted off, as shewn, to pre-
vent the limestone or other material lodging on the top thereof.
A division wall or walls may, if desired, be carried up from the bottom of the
kiln to the soffit of the arch a, and also above the block of brickwork A to the
top of the kiln. Such a wall beneath the arch is indicated by broken lines,
and a wall above such block is similarly indicated.
A corresponding arrangement of flues to that above described may be built in
cach side of the kiln, with the openings for the passage of the products of com-
bustion arranged in the sides of the kiln; but in such case only one of the sets
of hot air flues is used at each side of the kiln, and such set is arranged in position
between the flue from the producer and the inside of the kiln. This modification
of the invention is illustrated by Figure 6, which is a corresponding view to
Figure 2. It will be seen that there is an arrangement of flues and combustion
chamber at each side of the kiln, each of which corresponds to the arrangement
of flues in the block of brickwork A, as shewn by Figure 2, except that one set
only of flues of is shewn in each arrangement, namely, at the inner side of the
gas flue baud combustion chamber D. The passage-way between the arrange-
ments of flues at opposite sides of the kiln is about double the width of each passage-
way B shewn by Figure 2, and the products of combustion enter the material within
the passage-way, at opposite sides thereof, through the openings d from the com-
bustion chambers D. The hot air from the furnace collects under the arches a
which support the overhanging portions of the brickwork within which the sets
of flues are built, and passes up into the flues similarly as in the modification
previously described.
An arrangement such as shown by Figure 6 may be adopted in combination with
the arrangement first described, or in fieu thereof.
In some cases one arrangement of flues only, corresponding to one of the arrange-
ments shewn by Figure 6, may be used, namely, at one side of the kiln, the width
of the portion of the kiln at the front of the flues, measured from the side at which
such flues occur to the opposite side, being of suitable dimensions to allow of the
thorough permeation of the heat through the limestone or other material being
burni, In such case, of course, the central arrangement of flues described is dis-
pensed with.
While the method described of utilizing the hot air from the interior of the kiln,
for heating the external air on its passage to the combustion chamber, is a very
convenient one, and constitutes in itself a somewhat important feature of the
invention, the corresponding result may be obtained by modified methods of
utilizing the hot air for the purpose, such for instancy as by passing the external
air through pipes which pass through flues through which the hot air is drawn off
from the interior of the kiln, a special feature of this part of the invention being
the utilization of the hot air froin the kiln for the purpose by causing it to pass

page_text: by chimney draught, or by a mechanical appliance such as a fan, from the interior
of the kiln to the exterior air along a passage or passages which surround or are
adjacent to flues or passages through which the external air passes continuously
on its way to the combustion chamber.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. A kiln for burning limestone or other material into which the fuel is intro-
duced in a gaseous form from a producer, and from which air introduced into the
material through the lower portion of the kiln, and which has thereby become
heated, is withdrawn by chimney draught or by a mechanical appliance for the
purpose before it reaches the part of the kiln into which the products of combus-
tion pass from the combustion chamber into the material which is being burnt,
and is utilized to heat the air which is supplied to the combustion chamber, sub-
stantially as described.
2. A kiln for burning limestone or other material into which the fuel is intro-
duced in a gaseous form from a producer, and from which air introduced into the
material through the lower portion of the kiln, and which has thereby become
heated, is withdrawn in a continuous stream or streams by chimney draught, or
by a mechanical appliance for the purpose, before it reaches the part of the kiln
into which the products of combustion pass from the combustion chamber into
the material which is being burnt. and is utilized to heat the air which is supplied
to the combustion chamber, substantially as described.
3. In a kiln heated by producer gas, a gas flue from the producer and a com-
bustion chamber both passing across the middle of the kiln, means for introducing
air from outside the kiln into the combustion chamber, and a passage-way on each
side of the gas flue and combustion chamber for the passage of the material which
is being burnt, substantially as described.
4. In a kiln heated by producer gas, a combustion chamber, and also air flues
which communicate therewith, passing through the middle of the kiln, and a
passage-way at each side of such chamber and flues for the passage of the material
which is being burnt, substantially as described.
5. In a kiln heated by producer gas, a combustion chamber, a gas flue which com-
municates therewith, and air flues which also communicate therewith, all passing
through the middle of the kiln, and a passage-way on each side of such chamber
and flues for the passage of the material which is being burnt, substantially as
described.
6. In a kiln heated by producer gas, a combustion chamber passing across the
middle of the kiln, flues arranged within the kiln in the block of brickwork in
which the combustion chamber is formed and through some of which flues hot air
is drawn from the kiln by chimney draught, or a mechanical appliance for the
purpose, and through others of which air passes from the exterior of the kiln to
the combustion chamber and is heated on its passage by the hot air which is pass-
ing from the interior of the kiln, and a passage-way at each side between the flues
and the wall of the kiln for the passage of the material which is being burnt, sub-
stantially as described.
7. In a kiln heated by producer gas, a combustion chamber running along a side
of the kiln, flues arranged in the same side of the kiln. through one of which hot
air is drawn from the kiln by chimney draught, or a mechanical appliance for the
purpose, and through other of which air passes from the exterior of the kiln to
the combustion chamber and is heated on its passage by the hot air which is pass-
ing from the interior of the kiln, substantially as described.
8. In a kiln heated by producer gas, a gas flue passing from the producer across
the middle of the kiln, a combustion chamber running also across the middle of
the kiln, flues arranged within the kiln in the block of brickwork in which the gas

page_text: flue and combustion chamber are formed and through some of which flues hot
air is drawn from the kilu by chimney draught, or a mechanical appliance for the
purpose, and through others of which air passes from the exterior of the kiln to
the combustion chamber and is heated on its passage by the hot air which is pass-
ing from the interior of the kiln, and a passage-way at each side between the flues
and the wall of the kiln for the passage of the material which is being burnt, sub-
stantially as described.
9. In a kiln heated by producer gas, a gas flue passing from the producer along
a side of the kiln, a combustion chamber running also along the same side of the
kiln, flues arranged in the same side of the kiln through one of which hot air is
drawn from the kiln by chimney draught, or a mechanical appliance for the pur-
pose, and through other of which air passes from the exterior of the kiln to the
combustion chamber and is heated on its passage by the hot air which is passing
from the interior of the kiln, substantially as described.
10. In a kiln heated by producer gas, a gas flue passing from the producer across
the middle of the kiln, a combustion chamber running also across the middle of
the kiln and immediately over the gas flue, air flues running across the kiln
parallel with the combustion chamber, openings through the top of the gas flue
into the combustion chamber, openings from the air flues into opposite sides of
the combustion chamber, and outlet flues from opposite sides of the combustion
chamber to the material which is within the kiln, substantially as described; and
also the modified arrangement thereof in which a gas flue and combustion chamber
are arranged in a side of the kiln and in which the air passes into, and the products
of combustion pass out from, one side only of the combustion chamber, substantially
as described.
11. A kiln for burning limestone or other material and which is heated by pro-
ducer gas, constructed substantially as described with reference to Figures 1 to 5,
inclusive, of the drawings herewith.
12. A kiln for burning limestone or other material and which is heated by pro-
ducer gas, constructed substantially as described with reference to Figure 6 of the
drawings herewith.
13. The general combinations and arrangements of parts constituting modified
forms of kiln from the special combinations and arrangements of parts shewn by
the drawings, substantially as described.
1000
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Scor Ting to Cup gift sum paine
Wolverhampton, Agent for the Applicants.
STEPHEN WATKINS,