IMPROVEMENTS IN KILNS FOR BAKING AND BURNING ARTICLES IN
Year: 1853

page_text: THE PATENT to Alexander Thomson of Glasgow in the
County of Lanark, North Britain, Brick Builder, and David
Lockerbie, of the same place, Manager, for the Invention of
"IMPROVEMENTS IN KILNS FOR BAKING AND BURNING ARTICLES IN
County of Lanark, North Britain, Brick Builder, and David
Lockerbie, of the same place, Manager, for the Invention of
"IMPROVEMENTS IN KILNS FOR BAKING AND BURNING ARTICLES IN
EARTHENWARE.
"
Sealed the 15th March 1854, and dated the 16th September 1853.
PROVISIONAL SPECIFICATION left by the said Alexander Thomson
and David Lockerbie at the Office of the Commissioners of
Patents, with their Petition, on the 16th September 1853.
We, ALEXANDER THOMSON, of Glasgow, in the County of Lanark,
North Britain, Brick Builder, and DAVID LOCKERBIE, of the same
place, Manager, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN KILNS FOR BAKING AND BURNING ARTICLES IN
EARTHENWARE" to be as follows:-
This Invention relates to the arrangement and construction of kilns
or baking and burning furnaces suitable for baking and burning bricks
and pipes in such manner as to secure superior economy and efficiency
of action. According to one arrangement of kiln the structure is cir-
cular in plan, with a slightly convex arched top, the furnaces being

page_text: ranged all round the outside wall at certain determined intervals
asunder. Each furnace is thus fired and managed from the outside,
and the heated current from it passes away horizontally in a line con-
verging towards the centre of the kiln. But this line of direction
extends only through the main outer circular wall, and the current
then rises up in a vertical line between the interior surface of the
outer wall and the exterior surface of an inner circular wall, passing
all round the furnace and concentric with the outer wall. This
inner wall does not quite reach to the top of the kiln, sufficient
space being left for the passage of the current over the top of the
inner wall to enter the main body of the kiln. The annular passage
all round between the inner and outer walls is divided off into
sections to correspond to the furnaces, so that each upward heated
current has a special passage of its own; or the annular space may be
left clear instead of being thus divided; or the sections may be arranged
so as to be capable of being connected one with the other at pleasure.
The heat thus supplied to the interior of the kiln body then acts
directly upon the mass of articles being burned, and the combined
currents from the series of furnaces being joined together in the
kiln descend and pass through the perforated or open flue floor.
From the under side of this floor the currents then find their way
into horizontal converging flues, which pass direct to the foot of a
chimney built up from the foundation directly through the centre of
the kiln. Or, instead of thus conveying away the heat the combined
currents may be passed off' horizontally from beneath the floor to the
base of an external chimney. The general form of such a furnace
may be variously modified to secure the same results. And by a secon-
dary arrangement the waste heat from the kiln is made to pass away
by suitable bottom or other flues into drying stoves or chambers con-
taining green earthenware. By this latter plan what is ordinarily
waste heat is made economically useful in drying articles about to be
turned.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Thomson and David Lockerbie in the
Great Seal Patent Office on the 16th March 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we,
ALEXANDER THOMSON, of Glasgow, in the County of Lanark, North
Britain, Brick Builder, and DAVID LOCKERBIE, of the same place,
Manager, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of September, in the
year of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto us, the said Alexander Thomson and David
Lockerbie, Her special licence that we, the said Alexander Thomson
and David Lockerbie, our executors, administrators, and assigns, or
such others as we, the said Alexander Thomson and David Lockerbie,
our 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, ex-
ercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN KILNS FOR BAKING AND BURNING ARTICLES IN EARTHEN-
WARE," upon the condition (amongst others) that we, the said Alexander
Thomson and David Lockerbie, by an instrument in writing under
our hands and seals, or under the hand and seal of one of us, 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 immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the Alexander Thomson and David
Lockerbic, do hereby declare the nature of our said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained 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:
Our said Invention relates to the arrangement and construction of

page_text: kilus or baking and burning furnaces suitable for baking and burning
bricks and pipes and other earthenware articles in such manner as to
secure superior economy and efficiency of action. According to one
arrangement of kiln the structure is circular in plan, with a slightly
convex arched top, the furnaces being ranged all round: the outside
wall at certain determined intervals asunder. Each furnace is thus.
fired and managed from the outside, and the heated current from it
passes away horizontally in a line converging towards the centre of the
kiln. But this line of direction extends only through the main outer
circular wall, and the current then rises up in a vertical line between
the interior surface of the outer wall and the exterior surface of an
inner circular wall, passing all round the furnace and concentric with
the outer wall. This inner wall does not quite reach to the top of the
kiln, sufficient space being left for the passage of the current over the
top of the inner wall to enter the main body of the kiln. The annular
passage all round between the inner and outer walls is divided off' into
sections to correspond to the furnaces, so that each upward heated
current has a special passage of its own; or the annular space may be
left clear instead of being thus divided; or the sections may be
arranged so as to be capable of being connected one with the other at
pleasure. The heat thus supplied to the interior of the kiln body then
acts directly upon the mass of articles being burned, and the combined
currents from the series of furnaces being joined together in the kiln
<descend and pass through the perforated or open flue floor. From the
under side of this floor the currents then find their way into horizontal
converging flues, which pass direct to the foot of a chinney built up
from the foundation directly through the centre of the kiln. Or, instead
of thus conveying away the heat, the combined currents may be passed
off horizontally from beneath the floor to the base of an external chim-
ney. The general form of such a furnace may be variously modified to
secure the same results. And by a secondary arrangement the waste
heat from the kiln is made to pass away by suitable bottom or other
flues into drying stoves or chambers containing green earthenware.
By this latter plan what is ordinarily waste heat is made economically
useful in drying articles about to be burned.
And in order that our said Invention may be properly understood

page_text: we shall now proceed to describe the several figures on the two Sheets
of Drawings hereunto attached. Figure 1, on Sheet 1, of the Draw-.
ings is an external elevation, and Figure 2, a sectional elevation or
vertical section of a kiln constructed according to one modification of.
our Invention; Figure 3, on Sheet 2, of the Drawings is a plan, one.
half being in section; and Figure 4, comprises two horizontal half
sections taken at different heights. The kiln consists of a large cylin-:
drical chamber formed by the substantial fire-brick wall A, which is:
bound by a series of wrought iron hoops B, to prevent undue expansion:
from heat, and which is covered in by the convex roof C, built over
according to the system pursued in the construction of arches. The
lower portion D, of the wall A, is considerably enlarged in thickness,.
and in the thickness of the wall at this part are formed a number of (in:
this instance ten) furnaces E, all converging towards the centre of the.
kiln. The doors F, by which the furnaces are fed, are in the bevilled
portion G, of the wall immediately above the enlargement D, and are:
consequently directly over the front portions of the fire bars H. The
ash pits and small portions above the bars are open to the air draught
flowing in upon the fires, but the ingress of such draught may be regu-.
lated by dampers, if necessary. The furnaces are covered in by two con-
centric brick arches I, and the inner one can be renewed at pleasure,
when the action of the heat reuders this necessary, without interfering.
with the superincumbent wall. The flames and heated gases pass off
at the backs or innermost ends of the furnaces up the flues J, formed.
between the outer wall A, and an inner wall K, which forms the actual.
boundary of the kiln chamber. At their lower portions these flues aré
of the same width as the backs of the furnaces, but they become wider
as they rise (as is indicated in Figure 4), opening into the kiln chamber
by the mouths L, formed by cutting away portions of the wall K,
immediately below the roof G. From these flue mouths the flames and
heated gases bend downwards, impinging and operating upon the
articles in the kiln chamber. This downward direction of the flames
and heated gases is caused by the draught, the current of which is
through the perforated flooring M, of the kiln chamber. A portion of.
this flooring is represented in the left-hand portion of Figure 3, and

page_text: consists of a number of concentric annular rows of bricks disposed
radially. These bricks are of such a shape as when placed together
they touch only at their extreme ends, and leave spaces or longitudinal
slits at their central portions. It is by these slits that a communication
is formed with the draught passages beneath. The slits are not, however,
of uniform size throughout, for in order that the action of the flames
and gases may be rendered equal over the entire space it is necessary
to impede the draught at the centre. For this purpose the bricks
not only diminish in length as they approach the centre, but their
sides are also less indented, so as to form smaller interstices
or draught apertures at that part of the kiln chamber. This com-
pensating action is further aided by the arrangement of the flues N,
immediately beneath the perforated flooring M. These flues are repre-
sented as uncovered on the right hand side of Figure 4. The circular
space is divided radially into five or other convenient number of seg-
mental spaces, one of which is represented as uncovered on the left
hand side of Figure 3.. Each segmental space is partitioned off in such
a manner as to cause the current to take a very tortuous or labyrinthic
course, as indicated by the arrows towards the outer circumference, at
which part are the outlets O. These outlets communicate with a series
of horizontal flues P, lying at a still lower level, and converging radially
towards the centre of the kiln where they all open into the shaft of the
chimney Q, which rises vertically through the centre of the kiln. The
lower. flues P, are represented as uncovered on the left hand side
of Figure 4. In this instance these flues are five in number, as are
also the segmental divisions of flues N, immediately above, that is to
say, there is one flue to each alternate furnace, the outlets O, being
each immediately behind a furnace. This arrangement need not be
strictly adhered to, but it affords a means of conveniently working
dampers placed immediately below or across the descending passages
O, as these can be easily got at through the ash pits of the furnaces.
A damper R, is applied to the top of the chimney Q; this damper is
worked by a lever S, and chain T, passing down between guide pulleys
fixed on the salient angle portion of the kiln. The damper R, is
formed with a central spindle U, which works in guide eyes in cross

page_text: bars spanning the chimney's mouth. This arrangement prevents
liability to derangement from the shaking of the parts. The articles to
be burned are introduced through an iron framed doorway V, in the
wall A. When a charge is to be burned this door is built up and
cross bars W, are placed across it. These bars are formed with bent
ends to clasp and bind together three of the hoops B, which require to
be cut away at the door way, but which are formed with clamped or
bent back ends to grasp the ends of the bars W. A ring of openings X,
are left in the roof, through which the state of the interior of the kiln
can be ascertained, and when not so made use of they are closed by
bricks. Similar openings are formed or left immediately below the
furnace arches I, for the inspection of the furnaces, and these can be
closed in a similar manner. The furnace doors F, are hinged - to
brackets fixed to one of the binding hoops B, and they are opened by
means of chains Y, passing over pulleys Z, held in brackets fixed to
one of the more elevated hoops B.
Having now described and particularly ascertained the nature of our
said Invention, and the manner in which the same is or may be used
or carried into effect, we may observe, in conclusion, that we do not
confine or restrict ourselves to the precise details or arrangements
which we have had occasion to describe or refer to, as many variations
may be made therefrom without deviating from the principles or main
features of our Invention; but what we consider to be novel and
original, and therefore claim as the Invention secured to us by the
herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of kilus for baking
or burning articles of pottery or earthenware, as herein-before de-
scribed.
Second, the application and use in kilns of circumferential fires with
the heated currents therefrom, directed upwards through separate
channels in each case between inner and outer walls, and thence down-
wards converging towards the centre of the kiln.
Third, the system or mode of conveying off the heated currents from
the bottom of the kiln by passing the currents through a permeable
floor (the apertures in which floor gradually diminish in size or extent

page_text: as they approach the centre) into intermediate or lower labyrinthic pas-
sages, discharging the currents into the outer ends of radial bottom
flues passing to the chimney.
Fourth, the application and use in kilns of fuel supplying doors for
the furnaces disposed along the top of the annular portion of the
external wall.
In witness whereof, I, the said Alexander Thomson, on behalf
of myself and the said David Lockerbie, have hereunto set iny
hand and seal, this Fifteenth day of March, in the year of our
Lord One thousand eight hundred and fifty-four.
ALEXANDER THOMSON. (L.S.)