IMPROVEMENTS IN EARTHENWARE KILNS
Year: 1853

page_text: LETTERS PATENT to William Muir Campbell, of Glasgow, in the
County of Lanark, North Britain, Furnace Builder, for the In-
vention of "IMPROVEMENTS IN EARTHENWARE KILNS."
Sealed the 18th March 1854, and dated the 11th October 1853.
PROVISIONAL SPECIFICATION left by the said William Muir
Campbell at the Office of the Commissioners of Patents, with
his Petition, on the 11th October 1858.
J, WILLIAM MUIR CAMPBELL, of Glasgow, in the County of Lanark,
North Britain, Furnace Builder, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN EARTHENWARE KILNS" to be as
follows:-
This Invention relates to the so arranging kilus or ovens for burning
potteryware and other earthenware articles that great economy is
secured in the consumption of fuel, whilst the burning process is
conducted in an effective manner by means of very simple details of
the kiln. The kiln is circular in plan, and has a single furnace under
the bottom, and supplied from the outside, and communicating by its
flue with a central vertical flue, from which latter a series of horizontal

page_text: flues radiate outwards, and carry the heat directly through the mass of
articles to be burned. In this way the heat from the single furnace is
widely and evenly diffused throughout the kiln, as each radial current
rises directly up from the top of the radial flue by a series of suitable
apertures, and ascends through all the layers of articles, finally passing
off from the kiln by a single overhead central fluc on the top of the
kiln leading to the stalk. By a slight modification of this arrange-
ment the heat may be more equally diffused on entering the body of
the kiln. In this latter case the main single furnace has two side
elbow branch flues in addition to its direct radial fluc, so that when
advisable the central passage may be closed, and the two side branches
opened to admit the heat and flame to pass into the kiln at two points
pretty wide asunder. When so divided and diffused the heat from
each flue passes partly into an outside annular flue, and partly along the
radial flues to the centre. Again, instead of using one furnace only to
each kiln, a set of four or other convenient number may be employed.
Each of such furnaces is constructed and arranged in the manner first
described; but it opens at its inner end into a short vertical flue, and
the heated current rising a short distance up this flue passes back
towards the periphery of the kiln by a pair of radial or diverging
flues which diffuse the heat, as already described. As each furnace has
its own short vertical flue at its inner end, the entire set forms a
species of central ring, and the individual flues of this ring are again
connected together by a set of short radial flues which proceed to a
vertical central flue opening up through the body of the furnace.
this way, whilst part of the heat is diffused outwards by the duplex
radiating flues, part is also sent direct into the centre.
In
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Muir Campbell in the Great Seal
Patent Office on the 10th April 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WILLIAM MUIR CAMPBELL, of Glasgow, in the County of Lanark,
North Britain, Furnace Builder, send greeting.

page_text: WHEREAS Her Most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of October, in the year
of our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Muir Campbell, Her
special license that I, the said William Muir Campbell, my execu-
tors, administrators, and assigns, or such others as I, the said William
Muir Campbell, my executors, administrators, or 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 Inven-
tion for IMPROVEMENTS IN EARTHENWARE KILNS," upon the condition
(amongst others) that I, the said William Muir Campbell, by an instru-
ment in writing under my hand and seal, 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 months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that the said William Muir Campbell, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, reference being. had to the
accompanying Drawings, and to the letters and figures marked thereon,
that is to say:
My said Invention relates to the so arranging kilns or ovens for
burning potteryware and other earthenware articles that great
economy is secured in the consumption of fuel, whilst the burning
process is conducted in an effective manner, by means of very simple
details of the kiln. The kiln is circular in plan, and has a single
furnace under the bottom, and supplied with fuel from the outside, and
communicating by its flue with a central vertical flue, from which
latter a series of horizontal flues radiate outwards, and carry the heat
directly through the mass of articles to be burned. In this way the

page_text: heat from the single furnace is widely and evenly diffused throughout
the kiln, as each radial current rises directly up from the top of the
radial flue by a series of suitable apertures, and ascends through
all the layers of articles, finally passing off from the kiln by a
single overhead central flue on the top of the kiln leading to the
stalk. By a slight modification of this arrangement the heat be
may
more equally diffused on entering the body of the kiln. In this latter
case the main single furnace has two side elbow branch flues in
addition to its direct radial flue, so that when advisable the contral
passage may be closed and the two side branches opened to admit the
heat and flame to pass into the kiln at two points pretty wide asunder.
When so divided and diffused the heat from each flue passes partly
with an outside annular flue, and partly along the radial Hues to the
centre. Again, instead of using one furnace only to each kiln, a set
of four or other convenient number may be employed. Each of such
furnaces is constructed and arranged in the manner first described;
but it opens at its inner end into a short vertical flue, and the heated
current rising a short distance up this flue passes back towards the
periphery of the kiln by a pair of radial or diverging flues, which
As each furnace has its own
diffuse the heat, as already described.
short vertical flue at its inner end, the entire set forms a species of
central ring, and the individual flues of this ring are again connected
together by a set of short radial flues which proceed to a vertical
central flue opening up through the body of the furnace. In this way,
whilst part of the heat is diffused outwards by the duplex radiating
flues, part is also sent direct into the centre.
And in order that my said Invention may be properly understood, I
shall now proceed to describe the several Figures on the Sheet of Draw-
ings hereunto attached. Figure 1, is a sectional elevation or vertical
section of an earthenware kiln constructed according to one modification
of my Invention; and Figure 2, is a horizontal section of the same;
the two halves of the section being taken at different heights, one above
and the other below the flooring; and Figure 3, is a vertical section of
a modified form of furnace, which may be adopted under certain circum-

page_text: and 2.
stances in place of that represented in the complete views, Figures 1,
The kiln is a cylindrical structure or circular in plan, formed
by the fire-brck wall A, covered in by the convex roof B, or by a
conical or other shaped vent. At the lower part C of the wall A, it
is made of increased thickness, as well for giving increased strength to
the structure as for obtaining a sufficient depth for the formation of the
furnaces in the wall's thickness. In the present modification there are
four furnaces D, placed at equal distances apart around the kiln. The
fire bars E of these furnaces are on a level with the ground, the ash-
pits F being recessed into it, and having mouths in front of the
furnaces, which may be covered over more or less by the plates G, for
the purpose of regulating the influx of air beneath the bars. The fuel
is supplied by the doorway F, which can be closed more or less for the
purpose of regulating the draught by means of the counterbalanced
door or damper I. The fire box J extends inwards through the
wall A, C, and reaches to a short distance inside under the floor K
of the kiln chamber. A passage Kis formed at the back of the
furnace for the introduction of air for consuming the smoke of the
furnace, the air entering this passage from the ashpit F. On leaving
the fire box the flames and heated gases pass along the horizontal
flue I, towards the centre of the kiln. At a greater or less distance
from the outer wall, or near the centre of the kiln, the current from
each furnace diverges along two separate flues M, which return towards
the circumference of the kiln, and communicate with the "bag"
flue mouths N, arranged regularly round the kiln. These flue mouths
rise above the floor of the kiln, and emit the flames and heated gases
into the kiln chamber. The route of the currents of flame and gases
from the several furnaces is indicated in the Drawings by arrows.
The flues from all the furnaces communicate with each other in the
centre of the kiln floor, and a small portion of them enters the kiln
chamber at that point by the opening O. Independently of this central
opening the flooring K is not permeable. The space below it,
however, and in which lie the horizontal flues I and M, is at all parts
accessible to the flames and heated gases. To this effect, the brick

page_text: work upon which the floor is laid is arranged in rings or ramifications
so as to leave spaces P beneath the floor. The sides of the flues L
and M are so built, as represented in the vertical section, Figure 1,
as to leave interstices between the component bricks, and it is through
these interstices that the flames and heated gases gain access to the
spaces P. By these means the heat is diffused over the entire space,
whence it radiates upwards through the floor of the kiln chamber.
Air holes Q are formed through the kiln wall A, communicating with
the interior of the flue mouths N. These apertures can be closed at
pleasure by bricks R, a small ledge being built into the wall to sustain
the brick in front of the hole. The quantity of air admitted by these
apertures can be regulated with great nicety; but dampers of any
kind which will answer the desired end may be employed. Inspection
holes S are also formed in the walls at various points round the
circumference, and by means of these the state of matters in the
interior can at all times be ascertained. After operating upon the
articles deposited in the kiln chamber the gases pass off by a central
opening T in the roof, communicating with a chimney. In the modifi-
cation of furnace represented in Figure 3, the fire box J is made
greater in height than in the form herein-before described; and in
addition to the doorway H, it has a semicircular opening U, in the
front of the top of the furnace, by which the furnace is charged with
fuel. By this arrangement a greater quantity of air can be admitted
to the upper part of the fire than in the former modification, and by
this means the smoke is more effectually consumed, and the heat is
prevented from exerting too great a local action, and thereby injuring
the structure.
Having now described and particularly ascertained the nature of
my said Invention, and the manner in which the same is or may be
used or carried into effect, I may observe, in conclusion, that I do not
confine or restrict myself to the precise details or arrangements which
I have had occasion to describe or refer to, as many variations may be
made therefrom without deviating from the principles or main features
of my Invention. But what I consider to be novel and original, and

page_text: therefore claim as the Invention secured to me by the herein-before
in part recited Letters Patent, is,―
First, the general arrangement and construction of earthenware kilns,
is herein-before described.
Second, the system or mode of arranging and constructing earthen-
ware kilns, wherein one furnace is made to act for two "bag" flues.
In witness whereof, 1, the said William Muir Campbell, have
hereunto set my hand and seal, this Eighth day of April, in
the year of our Lord One thousand eight hundred and fifty
four.
W. M. CAMPBELL. (L.S.)