IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF KILNS FOR BURNING BRICKS, TILES, AND OTHER SIMILAR GOODS
Year: 1877

page_text: LETTERS PATENT to William Bull, of Portswood, in the County of Hampshire,
Civil Engineer; for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION
AND WORKING OF KILNS FOR BURNING BRICKS, TILES, AND OTHER SIMILAR
GOODS."
ealed the 21st August 1877, and dated the 11th June 1877.
PROVISIONAL SPECIFICATION left by the said William Bull at the Office
of the Commissioners of Patents on the 11th June 1877.
WILLIAM BULL, of Portswood, in the County of Hampshire, .Civil, Engineer..
"IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF KILNS FOR BURNING
BRICKS, TILES, AND OTHER SIMILAR GOODS."
This Invention mainly consists of improvements on my previous Invention set
forth in the Letters Patent granted to me on the 1st day of May, in the year of our
Lord 1874, for "Improvements in. Elame Kilns or Ovens for Baking or Burning.
Bricks or other Goods by Means of Continuous Firing," and in iny further Invention
set forth in the Letters Patent granted to me on the 31st day of May, in the year
of our Lord 1875, for "Improvements in the Construction of Kilns for Burning
Bricks and other Goods."
I have found by experience that although by means of the method set forth in
my first Specification aforesaid I obtain a certain economy of fuel, yet the per-
centage of first-class goods produced is not high; and further, that although by
ineans of the method set forth in my second Specification aforesaid I also effect
economy of fuel, yet the working of the kiln is attended with some difficulties. Now
my present Invention consists of an improved process whereby what is now known
as the Hoffman system of firing such kilns from the top is worked in combination
with methods whereby the goods are thoroughly -and completely dried, and if
required, partly burnt before being submitted to said firing. By such means the
economy of fuel resulting from the so-called top firing is combined with the
advantage of producing a higher class of goods.of better surface colour.
My kiln is by preference built with parallel walls open at top, but it may also be
arched over. The ground plan can be in one straight piece of any convenient
length, or it may be circular, elliptical, or oblong, or of other suitable shape.
Prine 77

page_text: For intermittent working I prefer the straight form, and for constant working
the annular or ring shape in plan. Furnace mouths are constructed at the bottom
of these parallel or concentric walls respectively at appropriate distances apart, and
with a suitable rise from the outside to the inside of the said walls, and for starting
the kiln similar furnace mouths are left in a cross wall, temporarily or per-
manently constructed, as the case may be, for starting the working. Doors for
convenience of unloading are left at intervals of about every tenth furnace opening,
more or less.
I further employ a moveable metal chimney or chimnies fixed on a framework,
set on wheels, also noveable dampers of iron plates rivetted together, and I
adapt to the kiln, at suitable intervals, cast-iron feed pipes with removable caps to
be used for the said top firing. The goods to be burnt are set so as to leave furnaces
or combustion chambers opposite the aforesaid furnace mouths, which chambers are
continued of a lesser width to the top of the kiln. They are spanned by bricks at
regular intervals, both horizontally and vertically, on which the small coal, as it is
dropped from above, is intercepted in its fall, and is spread or distributed equally
over the entire cross section of the kiln.
In working the kiln feed pipes are placed at suitable intervals over the combustion
chambers aforesaid, preferably up to about the tenth chamber, over which the
aforesaid chimney is to be fixed, and immediately beyond that a line of dampers.
The 15th and every 5th chamber, or thereabouts, should be similarly left open,
and dampers placed in the same way. All the top surface is covered in except at.
the feed pipes aforesaid and the openings from the moveable chimneys; one of the
moveable chimnies can now be set in position on the first opening, the furnace
mouths up to that opening closed up, and the fires started in the furnace in the cross
wall. By means of the comparatively low heat thus generated all the vapours get
driven off in course of time. This having been done, similar fires are started in the
second chimney section or length. By the time the bricks in this second length
have been completely dried there will be sufficient heat in the end of the kiln to
enable the top firing to be started. Prior to this the chimney should be moved to
its second position, and the feed pipes fixed over the first openings. These and all
other feed pipes, as far as the second position of the chimney should be covered and
the first line of dampers partly drawn. This being done, slow firing should be
started in the third chimney section or length, and so on in succession.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Bull in the Great Seal Patent Office on the 20th
October 1877.
WILLIAM BULL, of Portswood, in the County of Hampshire, Civil Engineer.
"IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF KILNS FOR BURNING
BRICKS, TILES, AND OTHER SIMILAR GOODS."
This Invention mainly consists of improvements on my previous Invention set
forth in the Letters Patent granted to me on the 1st day of May, in the year of our
Lord 1874, for "Improvements in Flame Kilns or Ovens for Baking or Burning
Bricks or other Goods by means of Continuous Firing," and in my further Inven-
tion set forth in the Letters Patent granted to me on the 31st day of May, in the
year of our Lord 1875, for " Improvements in the Construction of Kilns for Burning
Bricks and other Goods."
I have found by experience that although by means of the method set forth
in my first Specification aforesaid I obtain a certain economy of fuel, yet the
per-centage of first-class goods produced is not high, and further, that although
by means of the method set forth in my second Specification aforesaid I also effect
economy of fuel, yet the working of the kiln is attended with some difficulties.
.

page_text: Now my present invention consists of an improved process, whereby what is now
known as the Hoffinan system, of firing such kilns from the top, is worked in com-
bination with methods whereby the goods are thoroughly and completely dried, and
if required partly burnt before being submitted to said firing. By such means the
economy of fuel resulting from the so-called top firing is combined with the
advantage of producing a higher class of goods of better surface colour.
My kiln is by preference built with parallel walls open at top, but it may also be
arched over. The ground plan can be in one straight piece, of any convenient length,
or it may be circular, elliptical, or oblong, or of other suitable shape.
For intermittent working I prefer the straight form, and for constant working
tho annular or ring shape in plan. Furnace mouths are constructed at the bottom
of these parallel or concentric walls respectively at appropriate distances apart, and
with a suitable rise from the outside to the inside of the said walls; and for starting
the kiln similar furnace mouths are left in a cross wall, temporarily or permanently
constructed, as the case may be, for starting the working. Doors for con-
venience of unloading are left at intervals of about every tenth furnace opening,
more or less.
I further employ a moveable metal chimney or chimnies fixed on a framework
set on wheels, also moveable dampers of iron plates rivetted together. I may also
employ in place of the moveable chimney fixed chimnies built at the sides of the
kiln, with an arrangement for disconnecting them, as the progress of the burning
may require. I also adapt to the kiln, at suitable intervals, cast-iron feed pipes
with removable caps, to be used for the said top firing. The goods to be burnt are
set so as to leave furnaces or combustion chambers opposite the aforesaid furnace
mouths, which chambers are continued of a lesser width to the top of the kiln.
They are spanned by bricks at regular intervals, both horizontally and vertically,
on which the small coal as it is dropped from above is intercepted in its fall,
and is spread or distributed equably over the entire cross section of the kiln.
In working the kiln feed pipes are placed at suitable intervals over the ccm-
bustion chambers aforesaid, preferably up to about the tenth chamber over which
the moveable chimney is to be fixed, or opposite which the aforesaid side dimensions
are to be built, and immediately beyond that a line of.dampers.
The 15th and every 5th chamber, or thereabouts, should be similarly left open and
dampers placed in the same way; if side chimnies are used they may be at intervals
of ten chambers, more or less, and the dampers set accordingly .All the top surface
is covered in except at the feed pipes aforesaid, and the openings from the inoveable
chimneys. The moveable chimney can now be set in position on the first opening,
or the first pair of side chimneys connected, the furnace mouths up to that opening
closed up, and the fires started in the furnace in the cross wall. By means of the
comparatively low heat thus generated all the vapours get driven off in course of
time. This having been done, similar fires are started in the second chimney section
or length. By the time the bricks in this second length have been completely dried
there will be sufficient heat in the end of the kiln to enable the top firing to be
started. Prior to this the chimney should be moved to its second position, and the
feed pipes fixed over the first opening; or the second pair of side chimnies may be
connected and the first pair disconnected. All feed pipes as far as the second
position of the chimney should be covered, and the first line of dampers partly
drawn. This being done, slow firing should he started in the third chimney section
or length, and so on, in succession. In the meantime the top firing, which has been
started as aforesaid, will have been advancing, one line of feed holes having been
started, firing every four hours until five or thereabouts are being fired. This top
firing should be continued, in conjunction with the furnaces in the cross wall, until
the goods at the beginning of the kiln are properly burned. As soon as this is
the case each line of feed holes should be permanently closed and the fires in the
furnaces in the cross wall slackened, until about ten lines of feed holes are closed.
The firing in the furnaces in the end walls can then be stopped, and the furnace
mouths left sufficiently open to supply air for the combustion of the fuel. By

page_text: the time 5 or 6 feed holes have been fired the first line of dampers should
be withdrawn, the second partly raised, and the chimnies in the third position
connected. The kiln will now be in full working, and the operation described
will be repeated until the entire kiln is burnt out. As soon as the goods at the
commencement of the kiln are cool enough unloading can be commenced.
Having now described the nature and mode of carrying out my Invention, I.
wish it to be understood that I do not limit myself to the precise details herein
described, as the same may be varied without departing from the nature of my
Invention, but I claim as my Invention of Improvements in kilns for burning
bricks, tiles, and other similar goods,―
Firstly. The method of double firing as set forth, whereby one division or part of
a kiln as described is applied to drying or partly burning the goods, and another
division or part to completely burning the said goods.
Secondly. The mode of setting the goods to be dried and burned by means of my
method of double firing, substantially as set forth and described.
Thirdly. The combination of the furnaces as used for bottom firing alone, with
the vertical combustion chambers as used for top firing alone, substantially as set.
forth and described..
In witness whereof; I, the said William. Bull, have hereunto set my hand
and seal, this Eighteenth day. October, in the year of our Lord One
thousand eight hundred and somente coVAN