IMPROVEMENTS IN POTTERS' OR EARTHENWARE KILNS
Year: 1853

page_text: LETTERS PATENT to William Múir Campbell, of Glasgow, in the
County of Lanark, North Britain, Furnace Builder, for the Inven-
tion of "IMPROVEMENTS IN POTTERS' OR EARTHENWARE KILNS."
Sealed the 22nd March 1854, and dated the 13th October 1853.
PROVISIONAL SPECIFICATION left by the said William Muir
Campbell at the Office of the Commissioners of Patents, with his
Petition, on the 13th October 1853.
I, WILLIAM MUIR CAMPBELL, of Glasgow, in the County of Lanark,
5 North Britain, Furnace Builder, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN POTTERS OR EARTHENWARE KILNS"
to be as follows:-.
This Invention relates to the so arranging or applying heat to kilns
or ovens for baking and burning potteryware and other earthenware
0 articles that great economy in fuel is secured, whilst the burning process
is conducted in a more uniformly effective manner than has been hitherto
done. The kiln is preferred to be circular in plan, and is fitted with
four or other convenient number of furnaces supplied from the outside,
each furnace being set radially as regards the kiln's centre, the indivi-
5 dual furnaces of the series being at equal distances asunder. In cach

page_text: case the heated current passes from the furnace, which is itself in the
wall, through the external kiln wall, and then enters an exterior con-
centric flue running round the interior of the wall. The level of the
furnaces is below that of the kiln floor, and when the current has passed
into the outer concentric flue it diverges right and left and traverses
this flue, finally, turning from it into a radiating flue.at each end of such
traverse, conducting the current along beneath the kiln floor to the
central chimney. Similarly other intermediate flués run direct from the
outside concentric-flue along-the-floor or beneath it-to-the central
chimney. By this means the heated currents are widely and uniformly
diffused through the articles to her treated in the kiln, as each radial
current rises directly up from the top of the radial fine through the floor,
and ascends through all the layers of articles to an overhead central
opening passing to the cone, or chimney: Each furnace has an adjustable
cast iron front plate with valved apertures for regulating the air admis-
sion, and on the top of the kiln is an, adjustable, bell-mouthed valve
covering the flue outlet to adjust the draught.
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 18th 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.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth 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 executors, admi-
nistrators, and assigns, or such others as the said William Muir
Campbell, my executors, administrators, or assigns, should at any
1.

page_text: 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 POTTERS' OR EARTHENWARE KILNS," upon the
condition (amongst others) that I, the said William Muir Campbell,
by an instrument in writing under my hand and seal, should par-"
ticularly 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 immediately after the date of the said Letters Patent.
NOW KNOW YE. that I, 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 or applying heat to
kilns or ovens for baking and burning potteryware and other earthen-
ware articles that great economy in fuel is secured, whilst the burning
process is conducted in a more uniformly effective manner than has been
hitherto done. The kiln is preferred to be circular in plan, and is fitted
with four or other convenient number of furnaces, supplied with fuel
from the outside, each furnace being set radially as regards the kiln's
centre, the individual furnaces of the series being at equal distances
asunder. In each case the heated current passes from the furnace,.
which is itself in the wall, through the external kiln wall, and then
enters an exterior concentric fue running round the interior of the
wall. The level of the furnace is below that of the kiln floor, and when
the current has passed into the outer concentric flue it diverges right
and left and traverses this flue, finally turning from it into a radiating
flue at each end of such traverse, conducting the current along beneath
the kiln floor to the central chimney. Similarly other intermediate flues
run direct from the outside concentric flue along the floor or beneath it
to the central himney. By this means the heated currents are widely

page_text: and uniformly diffused through the articles to be treated in the kiln, as
each radial current rises directly up from the top of the radial fluc
through the floor, and ascends through all the layers of articles to an
overhead central opening passing to the cone or chimney. Each furnace
has an adjustable cast iron front plate with valved apertures for regu-
lating the air admission, and on the top of the kiln is an adjustable bell-
mouthed valve covering the flue outlet to adjust the draught. That
portion of the heat which passes right and left along the annular or
segmental flue is in part also conducted with the interior of the kiln,
near the circumference thereof, through the vertical flues or "bags,"
one furnace to each two vertical flues.
And in order that my said Invention may be properly understood,
I shall now proceed to describe the several Figures on the Sheet of
Drawings hereunto attached. Figure 1, on the Sheet of Drawings
is a vertical section or sectional elevation of a kiln constructed ac-
cording to one modification of my said Invention; and Figure 2, is
a sectional plan of the same; one half being a horizontal section
taken below the floor of the kiln chamber, and the other half a
similar section taken above that floor. Figures 3, and 4, are vertical
sections in detail of modifications of furnace, slightly differing from that
represented in the complete views, Figures 1, and 2. The kiln is a
cylindrical structure or circular in plan, being formed externally by the
cylindrical wall A, and covered by the convex roof B. The furnaces C,
of which there are five, placed at equal distances apart in the present
example, are formed in the lower portion D of the wall A, which is of
an increased thickness all round at this part. The furnace is contained
in the thickness of the wall, and the fire bars are on a level with the
ground outside. The ashpit E, which is recessed into the ground,
extends in front of the furnace, and a cover plate F is provided for
regulating the draught through it to the under side of the fire bars.
There are two entrances G, H, into the furnace; the former being into
the vertical face of the furnace, and the other in the front horizontal
part of the top. In the modified form of furnace represented in Figure 3,
the fire space I, is smaller in capacity than that shewn in the main
views, whilst it has a single entrance J, which is more or less closed as

page_text: required by the counterbalanced door K. In this modification, as a
smaller quantity of air is admitted at the front entrance of the furnace,"
a passage L, is formed in the back of the furnace and ashpit, whereby
a current of air entering from the ashpit is made to impinge upon the
licated gases as they are about to leave the furnace for the purpose of
consuming the smoke. This back air passage may also be adopted;
if necessary, in the form of furnace represented in Figures 1, and 2.
The modification of furnace represented in Figure 4, differs from that
shewn in Figure 3, just described, in being higher, whilst the front
opening M, is divided into two entrances by the cross plate N. A
counterbalanced door O, is fitted to the upper entrance to regulate the
draught, whilst the lower one may be temporalily built up when neces-
sary. On leaving the furnaces the flames and heated gases enter a
horizontal annular flue P, lying below the floor Q of the kiln chamber,
and running round the inside of the wall A. This annular flue P
communicates with a series of vertical "bag" flue mouths R, arranged
at equal distances round the chamber, there being two such flue mouths
to each furnace, and it is through them that the greater portion of the
flames and heated gases rise into the kiln chamber. In addition, how-
ever, to these flues, each furnace communicates with a horizontal flue
S, radiating from the centre, at which point an opening is made through
the flooring, so as by admitting a portion of the flames and heated gases
at that part, to render the heat of the kiln equal throughout. The floor
Q, which is not permeable, except at the central opening, is laid upon
radiating lines of brickwork, leaving spaces T between them; and the
flames and heated gases have access into these spaces through the sides
of the flues, which are so built as to leave interstices between the bricks,
as is represented in Figure 1. The routes of the currents of flames and
gases from the several furnaces are indicated in the Drawings by arrows,
and these currents combining in the kiln chamber after operating upon
the articles submitted to their action, finally pass off by the central
opening U in the roof. This exit aperture is provided with a damper
V, actuated by the lever W, the cord X hanging down within reach of
the attendant. Small passages Y are formed through the wall A, which
enter the bag flues R a little below their mouths, and serve to regulate

page_text: the action of the kiln by the introduction of more or less air. Inspection
holes Z, are also formed at various points round the wall, and by means
of these holes 'the state of matters in'the interior can at all times' be
ascertained.
Having now described and particularly ascertained the nature of-niy
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 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 kilns or ovens for
baking and burning potteryware and other earthenware articles, as
herein-before described.
Second, the system or mode of constructing kilns, wherein the heated
currents pass from the furnaces right and left into an annular or seg-
mental and concentric flue, and tlíence into vertical flues or bags," in
combination with direct currents through radial flues to or towards thie
kiln's centre.
Third, the system or mode of constructing kilns, wherein the heat
from each individual furnace is passed direct into an annular or 'seg-
mental and concentric flue in combination with radial currents passing
towards the kiln's centre..
In witness whereof, I, the said William Muir Campbell, have
hereunto set my hand and seal, the Eleventh day of April,
in the year of our Lord One thousand eight hundred and
fifty-four.