IMPROVEMENTS IN KILNS
Year: 1852

page_text: LETTERS PATENT to Robert Cochran, of Glasgow, in the County of
Lanark, Potter, for the Invention of "IMPROVEMENTS IN KILNS."
Sealed the 14th January 1853, and dated the 11th October 1852.
PROVISIONAL SPECIFICATION left by the said Robert Cochran
at the Office of the Commissioners of Patents, with his Petition,
on the 11th October 1852.
I, ROBERT COCHRAN, of Glasgow, in the County of Lanark, Potter,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN KILNS" to be as follows:-
I shall most conveniently describe my Invention by first referring
to the existing ordinary system or mode of firing biscuit and gloss
earthenware, china, black ware, brown ware, salt glaze ware, and every
description of pottery ware, to all which, as well as to hardening on
kilns and flint and bottle glass furnaces, my Invention is appli-
cable. At present kilns for the above purposes are built round, oval,
or square, according to the pleasure or convenience of the parties.
Suppose an earthenware kiln of a round. form to be fourteen feet
diameter inside, and from fifteen to sixteen feet in height to the crown.
.

page_text: The centre of the crown has an opening of from eighteen inches to
two feet for carrying off the smoke, and upon the top of the kiln is a
cone to protect the crown, and in some cases a hovel is built round the
kiln to protect it. Such a kiln usually requires eight fire-places or
mouths, as they are called, situated at equal distances round the kiln
outside, projecting about twenty-one inches, raised about three and a
half feet in height, with an arch from the bottom raised about two feet.
These mouths have flues running under the floor of the kiln, and
meeting at an opening in the centre, immediately under the opening in
the crown, at which centre point a moveable funnel is placed every
time the kiln is fixed, and the fire and smoke drawn by this funnel to
the centre pass out at the opening in the top. Each of the eight
mouths has a small chimney stalk or bay, as it is called, placed inside
of the kiln, about three feet high, by which a portion of the flame is
drawn up the side of the kiln, and passes also at once out of the
opening in the top. The mouths are supplied with fuel from the top,
having in some cases a grate with bars for the fuel to rest on, although
generally the fuel rests upon the ground. The heat of the kiln is
usually regulated by leaving an opening-into the kiln above each
mouth, which can be closed by a common damper at pleasure. When
open, the flame is checked and forced down to the bottom of the kiln;
when closed, the flames flow freely to the top. In such a kiln there is
a door left for filling and emptying, generally about seven feet in height
by three in breadth. The quantity of coal required for a gloss kiln of
the description and dimensions now given would be about six waggons
of twenty-four hundred weight each, and a biscuit kiln would take
nine waggons. My Invention is applicable to any form of kiln, oval,
round, or other shape, and in describing it as applicable to a round
kiln the same description, with the difference required by shape, will
apply. I build the kiln without any opening in the centre of the
crown, and I reduce the number of mouths or fire-places, say to four,
although this number is not essential, it may be more or less, and as
one of my objects is to save fuel each mouth must be carefully fitted
with doors, grates, and bars so as to allow no escape of fuel; a bag is
required to each mouth of sufficient height to give an impetus to the

page_text: flame up the side of the kiln. There is a moveable funnel in the
centre of the kiln, carefully joined, erected to withinthree or four feet
of the top. This draws down the heated air which had ascended from
the mouths inside the kiln to the bottom of the kiln, where it is
received into flues. These flues are carried round or across the bottom
of the kiln from the centre to the sides, and are continued up the sides
to the shoulder, where each is brought out and carried over the top to
the centre, where the air and smoke pass into a small stalk on the top
of the kiln. A stalk of the size of an ordinary house chimney would
be sufficient to carry off. all the smoke that escapes, as it is almost
wholly consumed in the heated flues round the kiln, and this process is
facilitated by introducing a small current of cold air from the outside
of the kiln at the bottom of the tunnel. To facilitate the cooling of
the kiln, if that is desired, I give a direct communication from the
crown to the body of the kiln, by connecting it with the stalk by a
flue to shut and open with a damper; when open, the heated air would
pass direct from the body of the kiln to the stalk, in place of going
round by the flues, and thus the temperature would be rapidly reduced.
Ii kindling the kiln this connection may be made useful by opening
the damper, which gives an impetus to the flame. in starting, and
then shutting it and letting the flame take its course..
The advantage to be derived from this Invention is, that in place of
allowing the heated air to escape from the kiln after passing once
through it, as in the kiln in common use, the heated air is carried
round and round the kiln until almost all smokė is consumed, thus
saving fuel whilst obtaining more regular heat and greater certainty in
firing, and dispensing with the regulating holes or openings as in the
ordinary places.
The foregoing description of my mode of firing a kiln applies to a
kiln by itself, but the Invention is applicable to a kiln with a hardening
oi kiln or muffle attached. A hardening on kiln being attached to the
side of the kiln built without a chimney at top, or the chimney being
closed at its bottom with a damper, for the purpose of cooling or
starting the kiln, as already described, the heated air, after being
brought up the sides of the kiln to the shoulder, as before described, is

page_text: brough out and carried over or round the top in flues, which flues are
connected with flues in the hardening on kiln, which last are continued
down round its outer side to the bottom, and thence continued on the
bottom to the inner side of the hardening on kiln, where they meet in
a flue which connects with a stalk built apart, into which the heated air
and smoke is carried, and whence it is carried away. And to avoid the
necessity of a chimney or stalk to each kiln, the heated air and smoke
may be carried in the usual way from a kiln, or more than one, erected as
before described, but without a chimney on each, into a stalk built apart.
Another advantage may be also obtained from my Invention when
more than one kiln is used. The connection between one kiln and
the common stalk built apart being closed, the white heat already
formed in one kiln may be drawn into the next kiln ready for firing,
by opening flues connecting with the top and bottom of the next kiln,
in which the process of heating will be farthered at little expense.
But I do not claim the process of taking the heated air from a heated
kiln into a cold kiln as part of my Invention, nor do I claim as new
and of my Invention the carrying of the heated air and smoke from
one to another, or from one to a stalk built apart, or from several kilns
into one chimney stalk.
But I claim as new and of my Invention the system or mode
already described of heating or firing a kiln at a reduced expense,
and enabling the manufacturer to regulate the heating or firing
better than by any plan now in operation by means of a centre
funnel and flues in the bottom and flues in the sides meeting at
the top, through which the heated air is brought from the mouths
till it is finally carried out at the top on the outside, or there made
use of for heating the hardening on kiln or muffle, and then carried
away by a flue and vent or chimney stalk apart, or carried away to
another kiln, all in the manner before described, and which is appli-
cable to the firing of biscuit and gloss carthenware, china, black ware,
brown ware, salt glaze ware, and every description of pottery ware,
and hardening on ware, and flint and bottle glass furnaces.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Cochran in the Great Seal Patent
Office, on the 11th April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
ROBERT COCHRAN, of Glasgow, in the County of Lanark, send
greeting.
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-two, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Robert Cochran, Her special
licence that I, the said Robert Cochran, my executors, adminis-
trators, and assigns, or such others as I, the said Robert Cochran,
my executors, administrators, 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 KILNS," upon the condition (amongst others) that
I, the said Robert Cochran, by an instrument 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 immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Robert Cochran, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof (that is to say):
I shall inost conveniently describe my Invention by first referring to
the existing ordinary system or mode of firing biscuit and gloss earth-
enware, china, black ware, brown ware, salt glaze ware, and every
description of pottery ware, and flint and bottle glass kilns or furnaces.
At present kilns are generally built round, oval, or square, according to

page_text: the pleasure or convenience of the parties. Suppose an earthenware
kiln of a round form to be fourteen feet in diameter inside and from
The centre of the crown
fifteen to sixteen feet height to the crown.
has an opening of from eighteen inches to two feet for carrying off the
smoke, and upon the top of the kiln is a cone to protect the crown, and
in some cases a hovel is built round the kiln. Such a kiln usually
requires eight fire-places or mouths, as they are called, situated at equal
distances round the kiln outside, projecting about twenty-one inches,
raised about three and a half feet in height, with an arch from the
bottom raised about two feet. These mouths have flues running under
the floor of the kiln, and meeting at an opening in the centre, perpen-.
dicularly under the opening in the crown, at which centre point a
moveable funnel is placed every time the kiln is fired, and smoke drawn
by this funnel to the centre passes out at the opening in the top. Each
of the mouths has a small chimney stalk or bag, as it is called, placed
inside of the kiln, about three feet high, by which a portion of the flame
is drawn up the side of the kiln, and passes also at once out of the
opening in the top. The mouths are supplied with fuel from the top,
having in some cases a grate with bars for the fuel to rest on, although
generally the fiel rests upon the ground: the heat of the kiln is usually
regulated by leaving an opening into the kiln above each mouth, which
can be closed by a common damper at pleasure. When open, the flame
is checked and forced down to the bottom of the kiln; when closed, the
flame flows freely to the top. In such a kiln there is a door left for
filling and emptying, generally about seven feet in height by three in
breadth. My Invention is applicable to any form of kiln, oval, round,
square, or other shape, and in describing it as applicable to a round
kiln the same description, with the difference required by shape, will
apply. There may be various ways of applying it. I shall describe
the following, which will be sufficient to shew its application. I build
the kiln without any opening in the centre of the crown, and I reduce
the number of mouths or fire-places, say to four, although this number
is not essential, it may be more or less, and as one of my chief objects
is to save fuel each mouth should be carefully fitted with doors, grates,
and bars so as to allow no escape of fuel a bag is required to each

page_text: mouth of sufficient height to give an impetus to the flame up the side
of the kiln. There is a moveable. funnel in the centre of the kiln, care-
fully joined, built to within three or four feet of the top. The heated
air having ascended from the mouths inside the kiln is drawn down the
funnel to the bottom of the kiln, where it is received into flues: these
flues are carried round or across the bottom of the kiln from the centre
to the sides, where the heated air may be brought out and carried into
a separate stalk built apart, or it may be carried in continuous flues up
the sides to the shoulder, where each flue is brought out and carried
over the top to the centre, and there the air and smoke pass into a stalk
on the top of the kiln and escape, or the flues may again be carried
down the side to the bottom, then brought out, and carried into. the
stalk built apart.
The following is another application: The kiln being built as already
described, in place of taking the heated air from the mouths into the
centre funnel, I carry it into the flues in the side, which are to be built
up to about four feet from the top. These flues are continued down to.
the bottom, then carried across or round it to the centre funnel, through
which the heated air is carried to the top of the kiln, and then received
into the stalk whence it issues, or is carried over the crown by flues.
to a stalk built apart.
The following is a farther application: The kiln being built as
already described, I would now take the heated air from the mouths.up.
the side to the shoulder in flues where each is brought out and carried
to the centre funnel and by that, to the bottom, where it is received into
flues and carried round or across the bottom to the side, where the flues
may be brought out and carried into the stalk built apart or continued
up the side to the shoulder, and the air and smoke thence conveyed
away as described in first process.
The foregoing descriptions. of my mode of firing a kiln apply to a kiln
by itself, but the Invention is applicable to a kiln with a hardening on
kiln or muffle attached to it by flues. A hardening on kiln being thus
attached (either nearer or more remote, as convenience may suggest,)
to the side of the kiln, built without a chimney at top, the heated

page_text: air after being brought up the sides of the kiln to the shoulder, or up
the centre funnel, as before described, is brought out and carried over or
round the top in flues which are connected with flues in the hardening
on kiln, which last are continued down round the outer side of the
hardening on kiln to the bottom, along which they are carried to its
inner side, where they meet in a flue connecting with the stalk built
apart, into which the heated air and smoke pass and are conveyed away.
Again, if the flues are brought out at the bottom of the kiln, as de-
scribed in first process, and the hardening on kiln is built apart from
it, then I continue the flues to it, carrying them round it, and then the
heated air and smoke is conveyed in the usual way into the stalk built
apart. To avoid the necessity of a chimney or stalk to each kiln, the
heated air may be carried in the usual way from a kiln, or more than
one, erected as before described, but without a chimney on each, into a
stalk built apart.
Another advantage may also be obtained from my Invention when
more than one kiln is used: the connection between one kiln and the
common stalk built apart being closed, the heated air in one kiln may
be drawn into the next kiln that may be ready for firing by opening
flues connecting the kilns, by which the process of heating will be
quickened at little expense.
But I do not claim the process of taking the heated air from a
heated kiln into a cold kiln as of my Invention, nor do I claim as
new the carrying of the heated air and smoke from one kiln to another,
or from one to a stalk built apart, or from several kilns into one
chimney stalk, nor do I claim the causing the heat to ascend and
then to descend in a kiln.
But what I claim as new and of my Invention are the peculiar com-
binations and constructions herein described.
The advantage to be derived from this Invention is, and the principle
of it consists in this: that in place of allowing the heated air to escape
from the kiln after passing once through it, as in the plan commonly
used, the heated air is carried round and round the kiln until almost
all smoke is consumed, thus saving fuel whilst obtaining more regular

page_text: heat and greater certainty in firing, and dispensing with the regulating
holes or openings as in the ordinary plan.
In witness whereof, I, the said Robert Cochran, have hereunto set
my hand and seal, this Twenty-eighth day of March, in the
year of our Lord One thousand eight hundred and fifty-three.
ROBERT COCHRAN. (L.S.)
Witness,
ROB. LAMOND,
of the City of Glasgow, Solicitor.