Improvements in Kilns for Burning Bricks, Tiles, Earthenware Pipes, Pottery Ware, Cement, Lime, Gypsum, and similar Materials.
Year: 1896

page_text: Date of Application, 2nd Apr., 1896
Complete Specification Left, 2nd Feb., 1897-Accepted, 20th Mar., 1897
PROVISIONAL SPECIFICATION.
Improvements in Kilns for Burning Bricks, Tiles, Earthenware
Pipes, Pottery Ware, Cement, Lime, Gypsum, and similar
Materials.
We JOHN WEST, of Barfield House, Didsbury, and WILLIAM JOHN JENKINS,
of 340 Queens Road, Cheetham, Manchester, both in the County of Lancaster,
Engineers, do hereby declare the nature of this invention to be as follows:-
This invention for improvements in kilns relates to kilns burning gaseous fuel so
arranged that the various kilns of a set can be worked in rotation, and that the air
for combustion can be heated before arriving at the point of combustion by passing
through the kilns filled with goods already burnt and the products of combustion
after passing through the kiln on full fire go on through one or more kilns on their
way to the chimney heating up the unburnt goods gradually, thus utilizing the heat
in the burnt goods for increasing the temperature of combustion in the burning
kiln and carrying the heat forward for warming the unburnt goods, and has for its
objects the attainment of a better burnt product with a smaller expenditure of fuel,
better control of the process of burning and greater security against damage from
steaming.
This invention consists in the arrangement of the flues with their dampers
whereby fires can be maintained and regulated along both sides of the kilu and in
the means for taking the gases to the chimney out of the top of the chambers.
In one way of carrying this invention into practical effect the kilns are built
separately, each kiln being surrounded by its own boundary walls, or they are
built in the form of chambers within common boundary walls. The gas conduits
are placed preferably below the surface of the ground, and opposite each chamber
two outlets are provided from the main gas flue to supply the subsidiary gas flues
of each kiln or chamber. Each outlet from the main gas flue is fitted with a valve
of suitable type which when lifted allows gas to pass from the gas main into
the subsidiary gas flue, and when shut prevents the gas passing into the subsidiary
flue.
For the proper burning of all kinds of bricks, tiles, drain pipes, earthenware,
pottery, etc. it is necessary to have the distribution of heat in all parts of the kiln
or chamber as equal as possible. For this purpose we arrange the gas outlets at
intervals along two opposite sides of the kilu or chambers, and for circular kilns
the gas outlets are arranged at intervals all round the kiln. These outlets are also
placed at such a height in the kiln that the burning gases and flame ascend to the
top of the kiln and mingle there and spread over the whole surface of the kiln.
The burning or burnt gases then pass downward to the bottom of the kiln coming
in contact with the goode in every part of the kiln. To ensure an even distribution
of the heat all over the kiln outlets are arranged in the floor of the same in rows
every here and there, and where a tendency to imperfect burning of the goods
exhibits itself in working, the outlets are made wider, and conversely where the
burnt gases appear to get away too quickly the outlets are reduced. Below the
floor of the kiln and under each row of outlets a flue is provided to conduct
the burnt gases into the neighbouring kiln and the flues under one half of the floor
deliver their gases to one outlet provided with a damper, while the flues under the
other half of the floor deliver their gases to another outlet also provided with a

page_text: damper, but both these outlets are on the same side of the kiln as the next kiln to
be fired in rotation. The outlet nearest the back of the kiln communicates with a
flue which passes either through the back wall of the next kiln or under the floor
of the next kiln, then upwards into a horizontal flue built in the middle of the
wall dividing the kilns, which latter flue is provided with outlets at intervals
throughout its length these outlets being immediately above and corresponding to
the ducts from the subsidiary gas flue. The outlet nearest the front of the chamber
in which combustion is going on communicates with a vertical flue built in the
dividing wall, and thus conducts the burnt gases into a horizontal flue built in the
dividing wall between two kilns. There is no direct connection between the kilus
and the chimney flue but a movable tube or tubes is or are arranged to connect
the top of any kiln with the chimney flue; for this purpose a hole or a set of holes
provided with proper covers is or are made in the top of each kiln so that by
bringing the connecting tube or tubes over the hole or holes and connecting the
same at one end to the chimney flue and at the other to the hole or holes in the top
of the kiln a direct connection can be made with the chimney. When in the course
of the operations or drying or burning or cooling it is not desirable to connect
particular kilns directly with the chimney the connecting tube or tubes is or are
removed and the hole or holes in the top of the kiln is or are covered by means of
covers provided for the purpose.
Any number of kilns can be worked in rotation and for large sets of chamber
kilns the same arrangements of flues and passages will permit of the firing being
done at two three or more places at the same time according to the number of
chambers in the set.
To describe the construction of the various air and gas passages and flues and
their mode of working we will assume in the first place that the kiln to which they
are applied is of the chamber kind. The general construction of the kiln may be
of the Hofmann type consisting of a continuous arched passage of suitable width
and height, and circular, oval, or approximately rectangular in plan, but this
passage is divided by transverse walls into a series of chambers and each chamber
communicates with the outside by means of an aperture or wicket in the outside
walls, through which the goods can be taken into or out of the chamber. After
the goods have been put into the chamber the wicket is walled up air-tight in the
usual manner. The main gas flues are arranged either to pass entirely round the
outside of the kiln, or round one, two or three sides as most convenient. On plan
the gas flue is placed outside the walls of the kiln and below the ground, and
opposite each chamber two valves are arranged one on the right hand side and one
on the left. These valves admit and regulate the combustible gases to two
subsidiary gas flues at right angles to the main flue and parallel to the division
walls. The subsidiary gas flues are placed below the floor of the kilo or chamber.
at such a depth that the outlet flues from the chamber can pass over them. Each
subsidiary gas flue is placed somewhat nearer the centre of the kiln than the inside
of the division wall so that vertical ducts made in the side or top of the subsidiary
flue can conduct the combustible gas upwards to the burners without interfering
with the horizontal flues built in the centre of the division walls. The arrangement
is similar on each side of the chamber and there may be any desired number of
ducts so that the combustible gases can be delivered at small intervals all along
both sides of the chamber at any desired height above the floor. At a convenient
position in cach duct a firebrick tile is placed for adjusting the size of the outlet,
and these tiles are so placed that the gas is evenly distributed; at every outlet
the same quantity of gas as near as may be. The air for combustion is supplied
through the horizontal flues in the division walls, and outlets from the horizontal
flues are arranged immediately above the adjusting tile in each gas duct so that
the air and gases meet and mix in a proper manner for combustion to take place
and these points where the air and gases meet form the burners. The air for
combustion is either drawn into the kiln by the natural draught of the chimney or
it can be forced in by a fan or a blower, or an injector worked by a small jet of

page_text: compressed air or steam can be used if more convenient. If the supply is drawn
in by the draught of the chimney the air enters the kiln through one of the wickets
in a chamber, the goods in which are already burnt off and ready for removal or
being removed; the temporary wall in the wicket would in such cases be either
partially or wholly removed. Between the chamber of entrance of the air and
the chamber in which combustion is going on there would be one, two, three or
more chambers full of goods already burnt off and in various stages of cooling,
and the air in its passage becomes heated by contact with the heated goods. The
course of the air in the chambers and flues is as follows:-
On its entrance it is immediately drawn through the outlets in the floor of the
first chamber into the flues beneath, where it divides into two portions one of which
passes through the outlet nearest the back of the kiln or chamber into the passage
built either in the back wall of the next kiln or chamber or below the floor, then
upwards into the middle horizontal flue in the division wall and out of this flue into
the first closed chamber along one side through the ports immediately above the
gas ducts before described, the air then passes downwards through the heated goods
and out through the outlets in the floor. The second portion of air passes through
the outlet nearest the front of the kiln or chamber into the vertical flue in the
division wall, then into the top horizontal flue in the same division wall and out into
the first closed chamber through ports immediately above the gas ducts before
described, the air then passes downwards through the goods and out through
the outlets in the floor. The portion of air which passed through the ontlet near the
back wall of the chamber or kiln enters the first closed chamber or kiln along the
far side and that which passed through the outlet nearest the front of the kiln or
chamber enters the first closed chamber or kiln along the near side. After passing
the first closed chamber the passage of the air through each succeeding chamber is
the same as that just described until it enters the kiln or chamber on full fire where
one portion combines with the gas entering on the far side and the other portion
combines with that entering on the near side. The flame so produced ascends to
the top of the chamber or kiln and spreads evenly all over the surface of the kiln
under the arch, then the burnt gases descend through and amongst the goods and
out towards the chimney through the outlets in the floor of the kiln or chamber and
into the next. The gases then pass in exactly the same manner as described for
the course of the air through one two three or more kilns or chambers all filled
with unburnt goods where the waste heat is gradually absorbed in heating and
drying the goods preparatory to burning. As soon as the temperature of the burnt
gases becomes reduced in this manner to a point at which condensation of the
suspended moisture is likely to take place the gases and moisture are conducted
through the hole or holes in the top of the kiln or chamber into the movable con-
necting tube and to the flue leading to the chimney. It is important that the burnt
gases with the suspended moisture or vapour should be taken off finally in an
upward direction because the moist vapour being considerably lighter than the
burnt gases at the same temperature will always take the highest place in the kiln
or chamber and will condense against the cooler goods rather than descend with the
burnt gases.
As soon as the process of burning has proceeded in a kiln or chamber to a
sufficient extent the two gas valves are closed and those in the next chamber are
opened, the gas then enters the next chamber and the air travels through until it
comes in contact with the gas when it ignites because the heated flues are
sufficiently hot to cause ignition to take place. In cases where the nature of the
goods does not require a very high temperature we arrange one or a few small
passages in the division walls immediately above the burners so that a small
quantity of heated gases can pass through into the next chamber direct and the
passages thus become sufficiently heated to ignite the gas when turned on along the
near side. As soon as one side is lighted the gas valve on the other side can be
opened and the flames at the top of the kiln will ignite the gas throughout.
When partially dried goods are placed in a chamber or kiln, especially if the

page_text: latter is in frequent use and never as cold as the goods, they part with moisture,
and to prevent damage from steaming it is necessary to pass a current of air
through the goods to carry off the moisture, and when, in addition, the partly
cooled walls and roof of the kiln or chamber are radiating heat to the cooler goods
the process of drying is assisted and the heat utilized. In such cases the course of
the air should be upwards in any given chamber so that the specifically lighter
moisture may be carried with the air in a natural upward direction. If it is
necessary to deflect the current downwards it should only be done in spaces where
the temperature of the current will be increased so that the capacity of the air for
carrying moisture may also be increased. In our invention we arrange to do this
in the following manner :-
The dampers controlling the outlets from the floor of the chamber or kiln over
which the connecting tube is placed are closed and a second connecting tube is
placed over the next chamber so as to connect it with the chimney flue in the same
manner as its neighbour. The chimney draught then acts upon the chamber and
through it upon the remaining full chambers whose wickets are walled up ready for
burning in due course, but in all these cases the course of the air current is reversed,
that is to say, instead of the air passing downwards through the outlets in the floor
of the kiln or chamber and out through the ports in the horizontal flue in the
division wall it now passes in at the ports in the horizontal flues, downwards into
the flues under the floor of the neighbouring kiln or chamber, upwards through the
outlets in the floor of that chamber and through the goods in the chambers carrying
all moisture with it, then into the ports in the horizontal flues in that chamber and
downwards through the flues into the flues under the floor of the next chamber and
upwards through the goods and so on into the connecting flue into the chimney flue.
The horizontal flues and other passages having been less exposed to the air during
the processes of emptying and filling will be hotter than the chambers and will tend
to increase the temperature of the air and thereby increase its capacity for carrying
moisture. In cases where it is desirable to use a fan, a blower or an injector for
forcing the air for combustion into the kilns or chambers the air is brought to the
chamber of entry by a pipe or other conduit which is introduced into the kiln or
chamber either through a hole in the temporary wall for closing the wicket or into
a connection with the flues below the floor of the chamber but the temporary wall
is in these cases kept as nearly air-tight as practicable, the current of air then
passes onwards to the burning chamber as previously described. To prevent the
air supplied under a slight pressure from passing out in the wrong direction, the
two dampers which close the outlets from the floor of the kiln or chamber
immediately behind the kiln or chamber into which the air is supplied are closed so
that the air cannot blow backwards.
In cases where it is inconvenient to use a high chimney for obtaining the
necessary chimney draught an exhaust fan can be used to create a suction in the
chimney flue and to pass the whole of the moisture and burnt gases out of the kilns.
The kilns can also be arranged with flues in substantially the same manner when
the chambers are built with a series of transverse arches instead of the longitudinal
arch of the type described above. In this case the division walls will form the
piers from which the arches spring.
In the case of separate kilns the passages can also be similarly arranged and
with circular or beehive kilus an equivalent series of flues serving the same
purposes can also be provided.
In all cases the supply of gas can be regulated by means of the gas valves; the
supply of air can be regulated by means of the dampers closing the outlets from
the floors of the chambers: the chimney gases by a damper in each connecting
tube, and the air for drying damp goods also by the damper in the connecting tube.
Dated this 2nd day of April 1896.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.

page_text: Improvements in Kilns for Burning Bricks, Tiles, Earthenware
Pipes, Pottery Ware, Cement, Lime, Gypsum, and similar
Materials.
We JOHN WEST, of Barfield House, Didsbury, in the County of Lancaster, and
WILLIAM JOHN JENKINS, of Beehive Works, Retford, Nottinghamshire, late of
340 Queens Road, Cheetham, Manchester, in the County of Lancaster, Engineers,
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 for improvements in kilns relates to kilns burning gaseous fuel so
arranged that the various kilns of a set can be worked in rotation, and that the
air for combustion can be heated before arriving at the point of combustion by
passing through the kilus filled with goods already burnt and the products of
combustion after passing through the kiln on full fire go on through one or more
kilns on their way to the chimney heating up the unburnt goods gradually, thus
utilizing the heat in the burnt goods for increasing the temperature of combustion
in the burning kiln and carrying the heat forward for warming the unburnt goods,
and has for its objects the attainment of a better burnt product with a smaller
expenditure of fuel, better control of the process of burning and greater security
against damage from steaming.
This invention consists in the arrangement of the flues with their dampers
whereby fires can be maintained and regulated along both sides of the kiln and
in the means for taking the gases to the chimney out of the top of the chambers.
In one way of carrying this invention into practical effect the kilns are built
separately, each kiln being surrounded by its own boundary walls, or they are built
in the form of chambers within comninon boundary walls.
The gas conduits are placed preferably below the surface of the ground, and
opposite each chamber two outlets are provided from the main gas flue to supply
the subsidiary gas flues of each kiln or chamber. Each outlet from the main gas
flue is fitted with a valve of suitable type which when lifted allows gas to pass from
the gas main into the subsidiary gas flue, and when shut prevents the gas passing
into the subsidiary flue.
For the proper burning of all kinds of bricks, tiles drain pipes earthenware
pottery &c. it is necessary to have the distribution of heat in all parts of the kiln
or chamber as equal as possible. For this purpose we arrange the gas outlets at
intervals along two opposite sides of the kiln or chambers and for circular kilns the
gas outlets are arranged at intervals all round the kiln. These outlets are also placed
at such a height in the kiln that the burning gases and flame ascend to the top of
the kiln and mingle there and spread over the whole surface of the kiln. The
burning or burnt gases then pass downward to the bottom of the kiln coming in
contact with the goods in every part of the kiln. To ensure an even distribution of
the heat all over the kiln outlets are arranged in the floor of the same in rows every
here and there and where a tendency to imperfect burning of the goods exhibits itself
in working the outlets are made wider and conversely where the burit gases appear
to get away too quickly the outlets are reduced. Below the floor of the kil and
under each row of outlets a flue is provided to conduct the burnt gases into the
neighbouring kiln and the flues under one half of the floor deliver their gases to
one outlet provided with a damper while the flues under the other half of the floor
deliver their gases to another outlet also provided with a damper, but both

page_text: these outlets are on the same side of the kiln as the next kiln to be fired in
rotation. The outlet nearest the back of the kiln communicates with a flue which
passes either through the back wall of the next kiln or under the floor of the next
kiln then upwards into a horizontal flue built in the middle of the wall dividing the
kilns which latter flue is provided with outlets at intervals throughout its length
these outlets being immediately above and corresponding to the ducts from the
subsidiary gas flue. The outlet nearest the front of the chamber in which com-
bustion is going on communicates with a vertical flue built in the dividing wall and
this conducts the burnt gases into a horizontal flue built in the dividing wall
between two kilns. There is no direct connection between the kilns and the chimney
flue but a movable tube or tubes is or are arranged to connect the top of any kiln
with the chimney flue. For this purpose a hole or a set of holes provided with
proper covers is or are made in the top of each kiln so that by bringing the
connecting tube or tubes over the hole or holes and connecting the same at one end
to the chimney flue and at the other to the hole or holes in the top of the kiln a
direct connection can be made with the chimney. When in the course of the
operations of drying or burning or cooling it is not desirable to connect particular
kilns directly with the chimney the connecting tube or tubes is or are removed and
the hole or holes in the top of the kiln is or are covered by means of covers
provided for the purpose.
Any number of kilns can be worked in rotation and for large sets of chamber
kilns the same arrangements of flues and passages will permit of the firing being
done at two three or more places at the same time according to the number of
chambers in the set.
In the accompanying drawings which show the invention applied to a kiln of the
Hofmaun type:-
Fig. 1 is a plan of a kiln constructed according to this invention.
Fig. 2 is a transverse section on the line A-B.
Fig. 3 is a sectional plan on line C-D, Fig. 2, and
Fig. 4 is a longitudinal section on line E-F Fig. 1.
The kiln consists of a continuous arched passage of suitable width and height
and circular oval or approximately rectangular in plan, but this passage is divided
by transverse walls K into a series of chambers and each chamber communicates
with the outside by means of an aperture or wicket L in the outside walls through
which the goods are taken into or out of the chamber. After the goods have been
put into the chamber the wicket is walled up air-tight in the usual manner. The
main gas flues M are arranged either to pass entirely round the outside of the kiln
or round one two or three sides as most convenient. The gas flue is outside
the walls of the kiln and below the ground and opposite each chamber two
valves N N are arranged one on the right hand side and one on the left. These
valves admit and regulate the combustible gases to two subsidiary gas flues OO
at right ar gles to the main flue and parallel to the division walls. The subsidiary
gas flues are placed below the floor of the kiln or chamber at such a depth that the
outlet flues P'from the chamber can pass over them. Each subsidiary gas flue is
placed as shown in Fig. 4 somewhat nearer the centre of the kiln than the inside
of the division wall so that vertical ducts Q made in the side or top of the subsidiary
flue can conduct the combustible gas upwards to the burners R without interfering
with the horizontal flues S S₁ built in the centre of the division walls K. The
arrangement is similar ou each side of the chamber and there may be any
desired number of ducts Q so that the combustible gases can be delivered at small
intervals all along both sides of the chamber at any desired height above the floor.
At a convenient position in each duct a firebrick tile T is placed for adjusting the
size of the outlet and these tiles are so placed that the gas is evenly distributed, at
every outlet the same quantity of gas as near as may be. The air for combustion
is supplied through the horizontal Hlues S S' in the division walls K, and outlets U
from the horizontal flues are arranged immediately above the adjusting tile Tin
each gas duct so that the air and gases meet and mix in a proper manner for

page_text: combustion to take place and these points where the air and gases meet form the
burners R. The air for combustion is either drawn into the kiln by the
natural draught of the chimney V or it can be forced in by a fan or a blower
or an injector worked by a small jet of compressed air or steam can be used
if more convenient. If the supply is drawn in by the draught of the chimney
the air enters the kiln through one of the wickets L in a chamber the goods in
which are already burnt off and ready for removal, or being removed, the
temporary wall in the wicket is in such cases either partially or wholly removed.
Between the chamber of entrance of the air and the chamber in which combustion
is going on there is one or more chambers full of goods already burnt off and in
various stages of cooling and the air in its passage becomes heated by contact with
the heated goods. The course of the air in the chambers and flues is as follows:-
On its entrance it is immediately drawn through the outlets W in the floor
of the first chamber into the flues P beneath where it divides into two portions
one of which passes through the outlet X nearest the back of the kiln or chamber
into the passage Y built either in the back wall of the next kiln or chamber or
below the floor then upwards through a vertical flue 7 into the middle horizontal
flue S' in the division wall K and out of this flue into the first closed chamber
along one side through the ports U immediately above the gas ducts Q before
described the air then passes downwards through the heated goods and out through
the outlets W in the floor. The second portion of air passes through the outlet Z
nearest the front of the kiln or chamber into a vertical flue 1 in the division
wall K then into the top horizontal flue S in the same division wall and out into the
first closed chamber through ports U immediately above the gas ducts Q before
described the air then passes downwards through the goods and out through the
outlets W in the floor. The portion of air which passes through the outlet near
the back wall of the chamber or kilu enters the first closed chamber or kiln along
the far side, and that which passes through the outlet Z nearest the front of the
kiln or chamber enters the first closed chamber or kiln along the near side. After
passing the first closed chamber the passage of the air through each succeeding
chamber is the same as that just described until it enters the kiln or chamber on
full fire where one portion combines with the gas entering on the far side and the
other portion combines with that entering on the near side. The flame so produced
ascends to the top of the chamber or kiln and spreads evenly all over the surface of
the kiln under the arch then the burnt gases descend through and amongst the
goods and out (towards the chimney) through the outlets W in the floor of the kilo
or chamber and into the next. The gases then pass in exactly the same manner as
described for the course of the air through one two three or more kilns or chambers
all filled with unburnt goods where the waste heat is gradually absorbed in heating
and drying the goods preparatory to burning. As soon as the temperature of the
burnt gases becomes reduced in this manner to a point at which condensation of the
suspended moisture is likely to take place the gases and moisture are conducted
through the hole 2 or holes in the top of the kiln or chamber into the movable.
connecting tube 3 and to the flue 4 leading to the chimney. It is important that
the burnt gases with the suspended moisture or vapour should be taken off finally
in an upward directiou because the moist vapour being considerably lighter than
the burnt gases at the same temperature will always take the highest place in the
kiln or chamber and will condense against the cooler goods rather than descend
with the burnt gases.
As soon as the process of burning has proceeded in a kiln or chamber to a
sufficient extent the two gas valves N are closed and those in the next chamber are
opened the gas then enters the next chamber and the air travels through until it
comes in contact with the gas when it ignites because the heated flues are sufficiently
hot to cause combustion to take place. In cases where the nature of the goods
does not require a very high temperature we arrange one or a few small passages 5
in the division walls immediately above the burners so that a small quantity of

page_text: heated gases passes through into the next chamber direct and the passages thus
become sufficiently heated to ignite the gas when turned on along the near side.
As soon as one side is lighted the gas valve on the other side is opened and the
Hames at the top of the kiln will ignite the gas throughout.
When partially dried goods are placed in a chamber or kiln especially if the
latter is in frequent use and never as cold as the goods, they part with moisture,
ud to prevent damage from steaming it is necessary to pass a current of air through
the goods to carry off the moisture, and when in addition the partly cooled walls
and roof of the kiln or chamber are radiating heat to the cooler goods the process
of drying is assisted and the heat utilized. In such cases the course of the air
should be upwards in any given chamber so that the specifically lighter moisture
may be carried with the air in a natural upward direction. If it is necessary to
deflect the current downwards it should only be done in spaces where the tempera-
ture of the current will be increased so that the capacity of the air for carrying
moisture may also be increased. In our invention we arrange to do this in the
following manner :-The dampers 6, 6 controlling the outlets X and Z from the
floor of the chamber or kiln over which the connecting tube is placed are closed and
a second connecting tube 31 is placed over the next chainber so as to connect it
with the chimney flue in the same manner as its neighbour. The chimney draught
then acts upon the chamber and through it upon the remaining full chambers whose
wickets are walled up ready for burning in due course. But in all these cases the
course of the air current is reversed that is to say instead of the air passing
downwards through the outlets W in the floor of the kiln or chamber and out
through the ports U U in the horizontal flues S S in the division wall it now
passes in at the ports U U in the horizontal flues S S¹ downwards into the flues P
under the floor of the neighbouring kiln or chamber upwards through the outlets W
in the floor of that chamber and through the goods in the chambers carrying all
moisture with it, then into the ports U U in the horizontal flues S S in that
chamber and downwards through the flues 1 and 7 into the flues P under the floor
of the next chamber, and upwards through the goods and so on into the connecting
flue 31 into the chimney flue 4. The horizontal flues and other passages having been
less exposed to the air during the processes of emptying and filling will be hotter
than the chambers and will tend to increase the temperature of the air and thereby
increase its capacity for carrying moisture. In cases where it is desireable to use
a fan, a blower or an injector for forcing the air for combustion into the kilns or
chambers the air is brought to the chamber of entry by a pipe or other conduit
which is introduced into the kiln cr chamber either through a hole in the temporary
wall for closing the wicket or into a connection with the flues below the floor of
the chamber but the temporary wall is in these cases kept as nearly air-tight as
practicable. The current of air then passes onwards to the burning chamber
as previously described. To prevent the air supplied under a slight pressure
from passing out in the wrong direction the two dampers 6, 6 which close
the outlets from the flour of the kiln or chamber immediately behind the kila or
chamber into which the air is supplied are closed so that the air cannot blow
backwards.
In cases where it is inconvenient to use a high chimney for obtaining the
necessary chimney draught an exhaust fau is used to create a suction in the
chimney flue and to pass the whole of the moisture and burnt gases out of the kilos.
The kilus can also be arranged with flues in substantially the same manner when
the chambers are built with a series of transverse arches instead of the longitudinal
arch of the type described above. In this case the division walls form the piers
from which the arches spring.
In the case of separate kilus the passages are also similarly arranged and with
circular or bee-hive kilns an equivalent series of flues serving the same purposes is
also provided.
In all cases the supply of gas is regulated by means of the gas valves N N: the

page_text: supply of air is regulated by means of the dampers 6, 6, closing the outlets from
the floors of the chambers: the chimney gases by a damper 8 in each connecting
tube 3, and the air for drying damp goods also by the damper 8 in the connecting
tube 31.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. In kilns for burning bricks, tiles and the like with gaseous fuel, in which the
various kilns of a set are worked in rotation so that the air for combustion is
heated before mixing with the gas and, the unburnt goods in one kiln heated by the
products of combustion from another kiln, the arrangement of flues and dampers.
whereby fires are maintained and regulated along both sides of the kiln sub-
stantially as described.
2. In kilns for burning bricks, tiles and the like with gaseous fuel, in which the
various kilns of a set are worked in rotation so that the air for combustion is
heated before mixing with the gas and the unburnt goods in one kiln heated by the
products of combustion from another kiln, conveying the gases from the top of the
chambers to the chimney in the manner substantially as described and illustrated
in the drawings.
3. The improvements in kilns for burning bricks, tiles earthenware pipes, pottery
ware, cement, lime, gypsun and similar materials, substantially as described with
reference to the drawings.
Dated this 2nd don of Fahru 1907
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.