IMPROVEMENTS IN KILNS FOR BURNING BRICKS, TILES, POTTERY RETORTS, AND OTHER FORMS OF CLAY WORK
Year: 1877

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
KILNS FOR BURNING BRICKS, TILES, POTTERY RETORTS, AND OTHER FORMS OF
CLAY WORK" A communication from abroad by William Tandy Christy,
of the City and County of St. Louis, State of Missouri, United States of
America.
Sealed the 24th April 1878, and dated the 1st December 1877.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 1st December 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN KILNS FOR BURNING BRICKS, TILES, POTTERY
RETORTS, AND OTHER FORMS OF CLAY WORK." [A communication from abroad by
William Tandy Christy, of the City and County of St. Louis, State of Missouri,
United States of America.]
This Invention relates to the construction of fire-brick kilns with exterior shells
of rivetted plate iron with thick fire-brick lining, in which the up draft alone is
used.
It also relates to a kiln in which the up draft, down draft, natural draft, and
pressure blast can be interchangeably used.
The principle of up draft is used for the easier promotion of combustion, and for
the further facility that it affords for the introduction of a blast of air of from one-
half pound to two pounds pressure to be directed under the fire bed for the purpose
of hastening the operation of final burning as soon as the brick or form is thoroughly
dried.
The great heat at which the brick is burned renders all other methods of kiln
construction inapplicable from their lack of power to resist lateral expansion, and
the unavoidable cracking and displacement that attend banded kiln.
any

page_text: Many years experience with the most approved kilns in present common use, and
Eufficiently practical use of this improved kiln, have demonstrated that all fire-clay
forms that are to be subjected to high stress in use if inherently incapable of
withstanding such stress are detected by partial or total destruction during the
burning.
All forms of fire-clay work, particularly lining brick tuyeis, nozzles, stoppers for
Bessemer work, glass pots, &c., when thoroughly dried by moderate heat, are capable
of being burned in two-thirds less time with two-thirds less fuel, and much less
labor than by the limited heat of the present systein, and possesses an exceed
ingly hard and sonorous body, with that uniform glazed surface, so indicative tho
highest qualities of resistance to heat or corrosion.
Fifteen tons of file-clay, in such forms as above named, when thoroughly dried by
modorate heat, can be most perfectly burned with a consumption of about fifty
bushels of coal when under a pressure of two pounds of blast. A full kiln can be
properly burned thus in eighteen to twenty-four hours.
The kilns of this Invention are constructed to contain from ten to sixty thousand
brick, more or less. The crown of the kiln is constructed of fire-brick. The skew-
backed bricks, being all within the iron shell, offer a firm and comparatively
unyielding bed against which to set the arch.
The object of the Invention is to further effect in the construction of brick kilns
certain improvements, whereby the advantages of up draft, down draft, natural draft,
and pressure blast can be interchangeably used to a very rapid uniform and perfect
burning of bricks, pipes, tiles, pottery retorts, shells, or other forms of clay work
with avoidance of the loss that arises mainly in brick burning from the production
of an undue proportion of soft brick, and the bad utilisation of the fuel employed,
with a lack of means of control over its effective and positive action
The Invention also consists of an iron exterior shell for kilns of a sectional and
consequently portable form, so that it can be quickly taken apart and re-erected in
a new situation. Better means are also provided for heating the air before injection
into the firing places by the interior circular bustle pipe, having few or many radial
branchings terminating in blowing nozzles. It is preferred to use the kiln in blocks
of two or more, where the following successive routine may be maintained by the
interlinking of, say, four kilns by pipe connections, through which the escaping heat
from a fired kiln can be absorbed to a useful end in drying a green kiln.
The following valuable result then follows its proper application:-The kiln that
is burning affords escaping heat sufficient to fully dry a kiln of green clay work.
Hence there may be one kiln being set, one being drawn, one being burned, and one
drying out ready to fire. Fifteen to twenty hours affords time sufficient after
perfect diying to have the fullest heat drawn on, and the entire contents of the kiln
well burned.
The Invention consists, 1st, in the combination in a fire-brick kıln of a fire-brick
lined metallic shell with the arrangement of the blast pipes passing under the heated
kiln bottom, with each a regulating stock valve for tempering the blast, and having
also a many perforated pipe under each fire chamber for blowing air upward between
the grate bais, together with the upshaft, and the crown opening for the unimpeded
passage of the consumed and exhausted air and gases. The bench is provided
with fire-place openings, up drafts, channels for main, and branch air pipes, ash-pits,
and feed holes. The external motallic shell is of rivetted iron with an inside fire-
proof lining. The perforated blast pipes are underneath the firing grates, and are
supplied from the main and branch pipes, there being a three-way branch bulb at
the junction of the main and branch pipes, which are so placed as to leave all
possible strength to the kiln floor. By means of the regulating stock valves, the
blast may be cut off or regulated as desired. Side doors are provided for the re-
ception and delivery of goods The crown has a cential opening and flue, which
is lined with fire-brick, and provided with a register valve.
The Invention consists, 2ndly, in the sectional incasement, and the binding
clamps, combined with the arched skew back band, as heroafter described.

page_text: 3rdly. In the sliding tite valve, in combination with grating and change valve,
as hereafter described.
4thly. In the closed firing places, with balanced doors, combined with the slit
bridge, the cut-off valve tile, and the clinkering slot, as described.
The masonry work of the foundation of the kiln is built within the iron exterior
shell in its upper parts, and channels are formed in the foundation for the reception
of the supply and bustle pipes, and the branchings therefrom, also for the firing and
down draft pits. The exterior iron shell serves to strongly bind the foundation
through its extension downward below the pits and channel bottoms. It is made in
portable sections, which are held together when erected by locking joints, or by
means of bolts or clamps, or preferably by a binding clamp of peculiar form.
The shell may be single and lined with fire-brick, or doubled, having between the
shells a water space, which arrangement is the best as an incasement, and also the
most durable and economical. The double casement shell is also in sectional
and portable parts, and in the lower part the necessary mud valves may be
placed.
The
The firing places, of which there may be any desirable number, have balanced
doors provided with straps to retain heel of the balance doors from blowing out by
the blast pressure. The kiln auch, which is capable of being supported by trusses
and suspension rods therefrom when the span of the arch is long, has a skew back band
of great strength to prevent the spreading of an ordinary arch span. At the centre
of the arch is the up draft chimney, which is open only when the kiln is worked
up draft It is provided with a register by which the heat and flames are made to
pass down into the down draft pit There are wicket doors for filling or emptying
the kiln large enough for the passage of waggons entirely through the kiln, anil
having eyes for retaining the wicket bars when the kiln is filled and in heat
down draft pit below the kiln floor is covered by a fireproof grating, through which
the once used currents are drawn by the chinney, a valve being provided in the flue
between the kiln and the chimney for cutting off the down draft when the tile valve,
hereafter mentioned, is withdrawn. It is from this flue that the heated escaping
current of gases and air can be let off for intermediate use in drying out the work
that may be elsewhere in preparation for burning, the bustle pipe being con-
tained in a channel in the foundation of the kiln The heated foundation, when the
kiln is in heat, serves to heat the blast an before its use. The blast nozzles for blowing
into the firing places during up draft lead from branches of the bustle pipe, and pass
through holes in the bottom of the firing places. Flash walls are provided to
conduct the flames and heat up the sides of the kiln, and towards its dead angles.
In returning, the current passes downward into the down draft pit A splitting
bridge is used, with a pit in the rear for dividing the drafts in connection with the
opening of the changing valve, which cuts off the down draft and a valve tile, which,
when pushed in, change the flame and heat to the flash wall passages. In each fire-
place bottom is a slot, through which to draw the clinkers formed
The operation of the kiln is as follows -The setting of the kiln is similar to that
of any ordinary kiln, with only the necessity of arching over all the pits and down
draft grating. When the setting is completed, the wicket doors must be built up,
and the wicket braces inserted in the eyes therefor.
Fire-clay lumps or bats may be used for filling up the wickets or man-holes
when they are used. The green work in the kiln is next slowly dried. After full
drying the charge must be slowly and moderately heated, the down draft heat being
the safest heat. When all the water of combination is expelled from the clay, the
fires should be gradually increased in power. After the heat is raised to a dull red
it is of importance that it should be extended uniformly to the centre and angles of
the kiln.
To secure a diffusive heat, the changing valve should be let down in its flue, the
register then raised, and the blast used with light pressure until the entire charge
assumes a uniform bright cherry red heat If the peep holes show uniformity in
the prevalence of the heat, the fire and blast may be increased for a finishing

page_text: off heat From this point, if the firing is good, and the blast well regulated, twelve
hours will suffice to finish the burning in a manner inapproachable under dependence
upon natural draft and open burning
To cool off the kiln, and to secure strength to the brick or other goods by anneal-
ment, all passages capable of admitting air should be closed and luted well, the
register and change valve in particular. After a closure of twelve hours, these
latter valves may be opened, and by the well-known tendency of heated currents,
the taller chimney will exhaust the heat from the kiln, while the cool external air
will descend the up draft chimney. The heat abstracted from the hot kiln it is
proposed to conduct into other kilns by means therefor, to do intermediate service in
drying, preparatory to firing these kilns.
The operation of filling and emptying the kilns can be greatly facilitated by
having a number of man-holes at different levels.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Alexander Melville Clark in the Great Seal Patent Office on the 1st June
1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN KILNS FOR BURNING BRICKS, TILES, POTTERY
RETORTS, AND OTHER FORMS OF CLAY WORK" A cominunication from abroad by
William Tandy Christy, of the City and County of St Louis, State of Missouri,
United States of America.
This Invention relates to the construction of fire-brick kilns, with exterior shells
of rivetted plate iron with thick fire-brick lining, in which the up draft alone is
used.
It also relates to a kiln, in which the up draft, down draft, natural draft, and
pressure blast can be interchangeably used.
The principle of up draft for the easier promotion of combustion is used, and for
the farther facility that it afforda for the introduction of a blast of air of from one
half pound to two pounds pressure, to be directed under the fire-bed for the purpose
of hastening the operation of final burning as scon as the brick or form is thoroughly
dried.
The great heat at which the bricks are burned renders all other methods of kiln
construction inapplicable from their lack of power to resist lateral expansion, and
the unavoidable cracking and displacement that attend any banded kiln
Many years experience with the most approved kilns in present common use, and
sufficient practical use of this improved kiln, enable me to state the following
facts All firo-clay forms that are to be subjected to high stress in use if inherently
incapable of withstanding such stress are detected by partial or total destruction
during the burning.

page_text: All forms of fire-clay work, particularly lining brick tuyeres, nozzles, stoppers for
Bessemer work, glass pots, &c., when thoroughly dried by moderate heat are capable
of being burned in two-thirds less time, with two-thirds less fuel and much less
labor than by the limited heat of the present system, and possess an exceedingly
5 hard and sonorous body with that uniform glazed surface so desirable to the furnace
man, and so indicative of the highest qualities of resistance to heat or corrosion.
Fifteen tons of fire-clay in such forms as above named, when thoroughly dried by
moderate heat, can be most perfectly burned with a composition of about fifty
bushels of coal when under a pressure of two pounds of blast. A full kiln can be
properly burned thus in 18 to 24 hours.
The improved kilns of this Invention are constructed to contain from ten to sixty
thousand bricks, more or less The crown of the kiln is constructed of fire-brick.
The skew-backed bricks all being within the iron shell offer a firm and comparatively
unyielding bed, against which to set the arch.
I do not confine myself to the number of mouths or blasts that I
proper to use.
may think
The object of the Invention is further to effect in the construction of brick kilns
certain improvements, whereby the advantages of up draft, down draft, natural
draft, and pressure blast can be interchangeably used to a very rapid, uniforin, and
perfect burning of bricks, pipes, tiles, pottery, retorts, shells, or other forms of clay
work, with avoidance of the loss that arises mainly in brick burning from the pro-
duction of an undue proportion of soft brick, and the bad utilisation of the fuel
used, with a lack of means of control over its effective and positive action.
The Invention also consists in an ion exterior shell for kilns of a sectional and
consequently a portable form, by which if clay stock in a locality becomes exhausted,
or for other reasons, it can be quickly taken apart, and quickly re-erected after
change to a new location. There are also provided better means for heating the
air before injection into the firing places by the interior circular bustle pipe having
few or many radial branchings terminating in blowing nozzles.
The action of the improved kiln has been here confined to a single one, but it is
preferred to have blocks of two or inore, wherein the following successive routine may
be maintained by the interlinking of, say, four kilns by pipe connections through
which the escaping heat from a fired kiln can be absorbed to a useful end in drying
a green kiln. The following valuable result then follows its proper application.-
The kiln that is burning affords escaping heat sufficient to fully dry a kiln of green
clay work; hence there may be one kiln being set, one being drawn, one being
burned, and one drying out ready to fire. Fifteen to twenty hours afford time
sufficient after perfect drying to have the fullest heat drawn on, and the entire
contents of the kiln well burned.
I do not deem it necessary to show the blast generator, nor the means used, when
several kilns are worked consecutively for the intermediate utilisation of the heat
of a fired kiln for the purpose of drying green work in set kilns prior to the final
escape of the gas and air currents into the chimney stack.
The following is a description of the kiln with reference to the appended Drawings,
in which,
Figure 1 is an elevated section.
Figure 2, a horizontal section showing the bench, the firing mouths, and up
drafts.
Figure 3 is a horizontal section passing below the grates, and showing the manner
of distribution of the air blast pipes.
Figure 4 is a side elevation.
Figure 5 is a sectional elevation.
Figure 6 is a plan view.
Figure 7 is a detail view of the device for fastening the sections together.
Similar letters of reference indicate corresponding parts.

page_text: To enable others skilled in the construction and use of kilns to make use of the
Invention I will proceed to describe particularly its various parts.
A. Figure 1, is a part of the foundation that is carried up thirty-nine inches. The
bench M is provided with the fire-place openings F, and the up drafts G, G, G, the
channels C, a, for the passage of the main pipe C, and branch air pipes c, c, c, the
ash-pit I, and feed hole f. B is the rivetted iron shell fourteen feet high and twelve
to sixteen feet diameter; D is the inside fire-proof lining, ordinarily nine inches
thick; E, Figuro 2, the firing grate, with the blast b underneath; H, H, H, side
doors for the reception and delivery of goods in either state; I ash-pit, seventeen
inches deep; a is a three-way branch bulb to main pipe C, which is ten inches in
diameter, and the branches c, c, c, four inches, with perforated cross pipe b, b, b;
these branches are placed, as shown, to leave all possible strength to the kiln floor;
h, h, h, are regulating stock valves; h³ shows the stock which, by turning, entirely
cuts off the nir, or allows regulated quantities up to the full blast; K is a register
valve; the feed holes f, f, are stopped by placing tiles over thom. The fionts of tho
fire-places and ash-pits are closed tightly by closely fitting tiles The jams of tho
fire-placos and the cover tiles of the arches are of the very best quality of fire-proof
work. Any style of blast may be employed. The crown N is made of the best
fire-brick, having an opening three feet in diameter for the flue L, which is lined
with fire-brick.
Figure 5 shows the foundation of a kiln, which may be either round or square.
The masonry work of the foundation should be substantial, built within the iron
exterior shell in its upper parts, and having the floor elevated above the yard
surface. Channels are formed in the foundation for the reception of the supply and
bustle pipes and the branchings therefrom, also for the firing and down draft pits.
The exterior iron shell serves to strongly bind the foundation through its extension
downward below the pits and channel bottoms. The iron shell is made in portable
sections as to size and weight. Its parts are to be held together when erected by
locking joints or by means of bolts or clamps, the joint shown, Figure 7, being
proferred, it being incollapsible.
The shell may be single and lined with fire-brick, or double, having between the
shells a water space, which arrangement is the best as an incasement and also the
most durable and economical.
A¹, Figure 4, 5, and 6, shows the iron shell; A², Figure 7, illustrates the double
incasement shell in sectional and portable parts, in the lower part of which necessary
mud valves may be placed; a², same Figure, shows the locking joints.
B¹, B, Figures 4 and 6, show the firing-places, of which there may be any
desirable number; b, b², balance doors to firing places; b³, balance weight to fire-
doors. C, branches to bustle pipes; c², straps to retain heel of balance doors from
blowing out by the blast pressure; c³, pulley for chain for balance weight. D¹,
kiln arch, which is capable of being supported by trusses and suspension rods there-
from when the span of the arch is long; d, skew back band of great strength to
prevent the spreading of an ordinary arch span; d³, up-draft chimney, which is
open only when the kiln is worked up draft. E, E¹, wicket doors for filling or
emptying the kiln, they being large enough for the passage of waggons entirely
through the kiln; 6, e¹, eyes for retaining the wicket bars when the kiln is filled and
in heat; e, register, by which the heat and flames are made to pass down into the
down-draft pit G, Figure 5 This down-draft pit is covered by a fireproof grating
S', through which the once used currents are drawn by the chimney O¹; h, h³, ladders,
by which to reach the chimney d³; h³, platform, for helper to stand on while luting
down the register 3, which is made of fireproof matter. L', kiln floor; l, valve
for cutting off the down draft when the tile valve u', Figure 5, is withdrawn;
Hlue between chimney O' and the kiln. It is from this flue that the heated
escaping current of gases and air can be led off for utility, in drying out the work
that may be elsewhere in preparation for burning; m², m³, Figure 6, bustle pipe
contained in a channel in the foundation of the kiln. The heated foundation when

page_text: the kiln is in heat serves to heat the blast air before its use; n², n², Figure 4, blast
nozzles, for blowing into the firing places during up draft, and passing through
holes in the bottom of the firing places. 0%, down-draft chimney; o², o², flash walls,
to conduct the flames and heat up the sides of the kiln and toward its dead angles;
in returning the current passes downward into the pit G. R, fire-brick lining or
water space; R², lining of arch; r², 72, Figure 7, sections, showing the shell as a
water case; 3, stay bolts to water case. S¹, down grating; 8, 8, draft passages
through the grating S¹, which lead all the unused down-draft heat and gases into
the pit G¹ T, waggon roadway, level with floor of kiln bottom; t, 2, Figure 6,
entrance of blast nozzles into the firing places. U¹, splitting bridge for dividing
the drafts in connection with the opening of the valve ; u², valve tile, which
when pushed in changes the flame and heat to the flash wall passages; v², v², the
curient line when valve tile u' is pushed in; w², 20², w², pits in the rear of the
firing places,, Figure 6, slots in each fire-place bottom, through which to draw
the clinkers formed.
The operation of the kiln is as follows -The setting of the kiln is similar to that
of any ordinary kiln, with only the necessity of arching over all the pits and down-
draft grating. When the setting is completed the wicket doors must be built up
and the wicket braces inserted in the eyes therefor.
Fire-clay lumps or bats may be used for filling up the wickets or man-holes
when they are used. The green work in the kiln is next slowly dried. After full
drying, the charge must be slowly and moderately heated, the down-draft heat
being the safest. When all the water of combination is expelled from the clay the
fires should be gradually increased in power. After the heat is raised to a dull
red, it is of importance that it should be extended uniformly to the centre and
angles of the kiln.
To secure a diffusive heat the changing valve should be let down in the flue ³,
the register then raised and the blast used with light pressure until the entire
charge assumes a uniform bright cherry red heat. If the peep holes that are always
provided show uniformity in the prevalence of the heat, the fires and blast may be
increased for a finishing-off heat. From this point, if the firing is good and the
blast well regulated, twelve hours will suffice to finish the burning in a manner
mapproachable under dependence upon natural draft and open burning.
To cool off the kiln, and to secure strength to the brick or other goods by anneal-
ment, all passages capable of admitting air should be closed and luted well, the
register and change valve in particular; after a closure of twelve hours these latter
valves may be opened, and by the well-known tendency of heated currents the
taller chimney will exhaust the heat from the kiln, while the cool external air will
descend the chimney d³. The heat abstracted from the hot kiln it is proposed to
conduct into other kilns by means therefor, to do intermediate service in drying
preparatory to firing these kilns.
The operation of filling and emptying the kilns can be greatly facilitated by
having a number of man-holes at different levels.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is,―
1st The combination in a fire-brick kiln, substantially as described, of a fire-
brick lined metallic shell, with the arrangement of the blast pipes passing under the
heated kiln bottom with each a regulating stock valve for tempering the blast,
and having also a many-perforated pipe under each fire chamber for blowing air
upward between the grate bars, together with the up draft and the crown opening
for the unimpeded passage of the consumed and exhausted air and gases.
2nd. The sectional incasement A¹ and the binding clamps a², a², combined with
the arch skew back band d³, as and for the purposes herein described.
3rd. The sliding valve u³ in combination with grating S' and valve ², as and for
the purposes herein described.

page_text: 4th. The closed firing places with balanced doors 6%, combined with the split
bridge U¹, the cut-off tile valve u', and the clinkering slot a³, as and for the purposes
herein described.
•
•I,
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this First day of June, in the year of our Lord One 1
thousand eight hundred and seventy-eight.
A
AT DIZ