IMPROVEMENTS IN FLAMe Kilns OR OVENS FOR BAKING OR BURNING BRICKS OR OTHER GOODS BY MEANS OF CONTINUOUS FIRING
Year: 1874

page_text: LETTERS PATENT to William Bull, of Ewell, in the County of Surrey,
Civil Engineer, for the Invention of "IMPROVEMENTS IN FLAMe Kilns
OR OVENS FOR BAKING OR BURNING BRICKS OR OTHER GOODS BY MEANS OF
CONTINUOUS FIRING."
Sealed the 4th September 1874, and dated the 1st May 1874.
PROVISIONAL SPECIFICATION left by the said William Bull at the
Office of the Commissioners of Patents, with his Petition, on the
1st May 1874.
I, WILLIAM BULL, of Ewell, in the County of Surrey, Civil Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
FLAME KILNS OR OVENS FOR BAKING OR BURNING BRICKS OR OTHER GOODS BY MEANS
OF CONTINUOUS FIRING," to be as follows:-
The kiln may be in plan view of a circular, oblong, or any other
continuous form; the walls to be parallel and vertical 8 feet more or
less in height, and 12 feet more or less apart. At the bottom of each
wall openings about 9 inches wide and 12 inches high should be left at

page_text: intervals of 3 feet more or less. The floor is then to be built between
the parallel walls of the kiln 18 inches more or less in height; the
openings in the walls, already alluded to, to be carried across the whole
width through the flooring, and to be covered in with bricks set apart or
with fire-bars of metal to allow of the ashes dropping through and being
withdrawn through the openings in the kiln walls already described.
A few inches above each ash flue a circular or square firing flue is to be
left for the insertion of the fuel. These flues are to be kept closed by
any convenient method except when putting in fuel. The bricks or
goods to be burnt are to be set close together in walls one brick's length
in thickness parallel to the kiln walls. Between the walls of green
bricks and the kiln walls a space of 4 inches is to be left, and between
the walls themselves a space of 3 inches is to be left; these spaces
are for draught passages, and communicate with outlets at intervals to
be hereafter described. Opposite each firing flue, or over the ash fluc
and fire-bars, an opening is to be left in the walls of green bricks 18
inches more or less wide, and 2 feet more or less high, the whole taken
together forming a combustion chamber for the fuel, which is to be
inserted through the firing flues before described. These walls of green
bricks are to be carried up to within about a foot of the top of the kiln;
the whole should then be covered over with a layer of bricks flat, on
which is to be spread a layer of about 9 inches more or less of ashes, soil,
or rubbish to prevent the escape of the heat. At intervals of 40 feet
more or less a width of about 18 inches of the brick flat is to be left
open, over which, when required, a moveable chimney on wheels of any
convenient height extending the entire width of the kiln, and with one
or more square or circular outlets, may be placed as an outlet for the
steam and waste products of combustion.
5.
.
To set a kiln of this nature going it is necessary after the kiln itself is
constructed to build a temporary wall across the kiln between two flues
in any convenient. part. Starting from this the bricks or goods to be
burnt are to be set and the opening left for the escape of the steam and
other waste products, as before described. The layer of ashes or earth
is then to be spread, and to prevent this falling down the opening a
single brick wall is to be built up to the level of the top of the kiln
walls; over the opening thus made the moveable chimney is to be
placed. The setting is to be carried on regularly and the firing can now
be commenced in the first four flues and kept up as briskly as is con-
:
.
!.

page_text: sistent with a thorough combustion of the fuel. After 36 hours more
or less a fifth flue can be opened; after 48 hours, a sixth: The first
flue will now be ready to close, and when it is considered from the look
of the bricks and the settlement of the load that it has been burnt
enough this can be done, and the ash flue below it also. The seventh
flue should now be fired. As cach successive fluc is closed another is to
be opened, so that there are always six burning. Air for combustion of
the fuel should be admitted through the lower or ash flues as required
up to this.
Each kiln will have about 100 flues. On firing the forty-first flue
the lower or ash flue under that first fired can be opened, and after this.
all the ash flues (40 flues behind the part being fired) can be opened.
The air for combustion of the fuel will after this time be supplied
through the bricks burnt, and no more should be admitted through the
ash flues in the part firing than is absolutely necessary. In most cases
after the kiln is in full operation they, can be entirely closed. They
sliould in no case be allowed to become choked up with ashes.
After about 60 flues have been fired it will be found that the goods in
the part first fired will be cool enough to admit of being unloaded; this
can be done, and the operations of loading, firing, and unloading con-
tinued at pleasure.
+
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Bull in the Great Seal Patent Office on
the 5th September 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BULL, of Ewell, in the County of Surrey, Civil Engineer, send greeting.
• WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the First day of May, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs, and successors,
give and grant unto me, the said William Bull, Her special licence that

page_text: I, the said William Bull, my executors, administrators, and assigns,
or such others as I, the said William Bull, my executors, admini-
strators, and assigns, should at any time agree with and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN FLAME
KILNS OR OVENS FOR BAKING OR BURNING BRICKS OR OTHER GOODS BY MEANS OF
CONTINUOUS FIRING," upon the condition (amongst others) that I, the said
William Bull, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar month's next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Bull, do hereby declare
the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement:-
The kiln may be in plan view of a circular, oblong, or any other 2
continuous form; the walls to be parallel and vertical 8 feet more or
less in height, and 12 fect more or less apart. At the bottom of each
wall openings about 9 inches wide and 12 inches high should be left at
intervals of 3 feet more or less. The floor is then to be built between
the parallel walls of the kiln 18 inches more or less in height, the 2
openings in the walls already alluded to to be carried across the whole
width through the flooring, and to be covered in with bricks set apart,
or with fire-bars of metal, to allow of the ashes dropping through and
being withdrawn through the openings in the kiln walls already
described. A few inches above each ash flue a circular or square firing 3
flue is to be left for the insertion of the fuel. These flues are to be kept
closed by any convenient method except when putting in fuel. The
bricks or goods to be burnt are to be set close together in walls one brick's
length in thickness parallel to the kiln walls. Between the walls of green
bricks and the kiln walls a space of four and a half inches is to be left, 3
and between the walls themselves a space of three inches is to be left;
these spaces are for draught passages and communicate with outlets at
intervals to be hereafter described. Opposite each firing flue, or over

page_text: the ash flue and fire-bars, an opening is to be left in the walls of green
bricks 18 inches more or less wide, and two feet more or less high; the
whole taken together forming a combustion chamber for the fuel which
is to be inserted through the firing flues before described. These walls
of green bricks are to be carried up to within about a foot of the top of
the kiln; the whole should then be covered over with a layer of bricks
flat, if an arched top be not used, on which is to be spread a layer of
about 9 inches more or less of ashes, soil, or rubbish to prevent the
cscape of the heat.
At intervals of forty feet more or less a width of
about eighteen inches of the brick flat is to be left open, over which,
when required, a moveable chimney on wheels of any convenient height
extending the entire width of the kiln, and with one or more square or
circular outlets, may be placed as an outlet for the steam and waste
products of combustion.
To set a kiln of this nature going it is necessary after the kiln itself
is constructed to build a temporary wall across the kiln between two
flues in any convenient part. Starting from this the bricks or goods to
be burnt are to be set, and the opening left for the escape of the steam
and other waste products, as before described. The layer of ashes or
earth is then to be spread, and to prevent this falling down the opening
a single brick wall is to be built up to the level of the top of the kiln
walls over the opening thus made the moycable chimney is to be
placed. The setting is to be carried on regularly, and the firing can
now be commenced in the first four flues and kept up as briskly as is
consistent with a thorough combustion of the fuel. After thirty-six hours
more or less a fifth flué can be opened; after forty-eight hours, a sixth.
The first flue will now be ready to close, and when it is considered from
the look of the bricks and the settlement of the load that it has been burnt
enough this can be done, and the ash flue below it also. The seventh
flue should now be fired. As each successive flue is closed another is to
be opened so that there are always six burning. Air for combustion of
the fuel should be admitted through the lower or ash flues as required
up to this.....
Each kiln will have about one hundred flues. On firing the forty-first
fluc the lower or ash flúe under that first fired can be opened, and after
this all the ash flues (forty flues behind the part being fired) can be
opened. The air for combustion of the fuel will after this time be
supplied through the bricks burnt, and no more should be admitted

page_text: through the ash flues in the part firing than is absolutely necessary.
In most cases after the kiln is in full operation they can be entirely
closed. They should in no case be allowed to become choked up with
ashes.
After about sixty flues have been fired it will be found that the goods
in the part first fired will be cool enough to admit of being unloaded;
this can be done, and the operations of loading, firing, and unloading
continued at pleasure.
A moveable roof over the part being loaded may be found necessary.
In order to further explain the nature of my said Invention, and the
manner in which the same is to be performed, I annex the accompanying
Drawings, in which Fig. 1 shews a plan view of one end of an oblong
· kiln with circular ends. I give this example as it is a combination of a
circular and straight kiln, from which any other form of continuous
kiln can be constructed.
The kiln when complete would exhibit about one hundered flues, their
distance from centre to centre along the straight portions of the parallel
walls being three feet six inches, such distance varying at the circular
ends by reason of their radial direction.
It will be seen that intermediate flues are applied at the outer semi-
circle of the kiln in order to compensate for the increased space between
the radial flues, but these intermediate flues need only be carried partially
across the kiln to about the extent shewn in order that the burning may
be equalized as far as possible in all parts of the radial setting of the
goods.
The plan view shews five different levels of the kiln. A shews a
portion of the ground plan with spaces for the ash flues; B shews
section of kiln with flooring before setting the flues; C shews sectional
plan at level of firing flues with the method of setting the bricks for the
flues and draught passages; D shews sectional plan of top with covering
brick removed; and E shews plan of top with position of chimney F for
commencement of firing, when a temporary cross wall should be built
up at c¹, c¹, to start from. The arrows shew the direction of the draught
throughout the kiln when thoroughly at work.
Fig. 2 shews a cross section of the kiln at D, D, of Fig. 1, with
method of setting the bricks and draught passages.

page_text: Fig. 3 shows a cross section of the kiln with an arched top, if such
should be used, suitable openings being made for the moveable chimney
and for the supply of the goods, and an aperture at the top for gauging.
Fig. 4 shews an elevation and longitudinal section of a straight portion
of the kiln with chimney.
At Figs. 5 and 6 an enlarged plan and section of dummy are shewn.
for closing the mouths of the flues.
Fig. 7 shews a front view of sheet-iron chimney, capable of travelling
on rollers along the top of the kiln. The chimney is shewn with threo
outlets to which the tubes or flues 15 feet high are hinged or jointed so
as to be capable of being lowered down when necessary by means of the
ordinary suitable gearing.
a, a, represent the walls of the kiln; b, b, the firing flues; c, c, the
ash flues; d, d, the fire bars or bricks, set one inch apart to receive the
fuel; e, e, the walls or piles of bricks to be burnt, of which there are
twelve rows or walls, the number of bricks in the rows varying according
to the distances between the radial flues; g are permanent steps giving:
access to the kiln. It will be found in practice that the flues on the.
inside of the circular ends of the kiln will be ready to close before those
on the outside and in the proportion which the lesser length of inside
concentric walls bears to that of the outside. There will at times there->
fore be one or more flues less firing on the inside of the circle. The
firing is under easy control, and. the time for finally closing the flues can
be known by the amount of settlement. About two inches all over will
be found sufficient, and if one part settles more than another the firing
should be lessened in that particular part. The ashes or earth having
been spread evenly over the top of the kiln, if an open top be used, the
settlement can be determined by a straight edge; and by taking a.
sample brick from the top of the outer wall it can be ascertained when
the bricks are thoroughly burnt.
Kilns or ovens of the foregoing construction are also annlicable to

page_text: Having now described the nature of my said Invention, and the
manner in which the same is to be performed, I claim,—
The improved method of constructing flame kilns or ovens for burning
or baking bricks or other goods by means of continuous firing in
pursuance of the annular or endless system by forming the walls
without a top covering or arch (although such arch, may be applied
if desired), and by preventing the heat from escaping from the top of the
kiln by the application of an impervious layer of ashes, earth, or other
suitable material in order that the firing established in one part only of
the kiln may gradually advance, burning each part in succession.
•
I claim the application of a moveable chimney placed across the walls
of the kiln in advance of the firing, the waste heat of the burnt bricks
being utilized by the passage through them of the air for combustion of
the fuel, and after combustion being drawn.through the unburnt portion
by means of the moveable chimney..
1
г
I also claim the improvements in the construction of the kiln in regard
to the flues and floorings, and the method of setting the bricks in
reference thereto and to the walls of the kiln, in order that such setting.
may in itself produce or form combustion chambers in combination with
the flues, the bricks. being set in a series of parallel walls with alternate
passages from the bottom to the top of the kiln whereby a free draught
or current is established throughout the goods, all substantially as and
for the purposes herein specified.
In witness whereof, I, the said William Bull, have hercunto set my.
my hand and seal, this Sixteenth day of August, in the year
;