IM- PROVEMENTS IN POTTERY KILNS
Year: 1856

page_text: LETTERS PATENT to Robert Hannah, of Glasgow, in the County of
Lanark, North Britain, Pottery Manager, for the Invention of "IM-
PROVEMENTS IN POTTERY KILNS"
Sealed the 12th August 1856, and dated the 10th March 1856.
PROVISIONAL SPECIFICATION left by the said Robert Hannah at the
Office of the Commissioners of Patents, with his Petition, on the
10th March 1856.
I, ROBERT HANNAH, of Glasgow, in the County of Lanark, North Britain,
Pottery Manager, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN POTTERY KILNS," to be as follows, that is to say:
This Invention relates to the so arranging and constructing the furnaces of
"biscuit," "gloss," and other kilns or ovens for burning, hardening on, and
enamelling pottery ware or earthenware as to secure increased economy in the
consumption of fuel, and a saving of expense in repairs, together with other
practical advantages.
Kilns of the class to which this Invention refers are generally made circular
in plan, and the furnaces are placed in an enlargement of the structure running
round the lower part of the circumferential wall of the kiln chamber, such
enlargement forming a step or bench, as it were, round the wall, with a flat
top and with vertical sides. A "glut" or doorway is usually formed for each
furnace in the vertical face of the wall for clearing out the furnace; this door-

page_text: way is built up and closed when the kiln is in operation. In addition to this
side door, there is usually an opening in the top of the furnace in that part
which forms a horizontál top of the step or bench, which opening is for
feeding the fire by and for admitting air. It is found, however, in practise
that this top opening is the cause of a great waste of fuel, as much smoke
and heated gases escape thereat; and as it is necessary to use large pieces of
coal to insure the proper action of the fire, and to regulate the access of
the air thereto, as is well understood by the practical pottery manufacturer.
Now, the present Invention consists, according to one modification, in form-
ing this secondary opening for feeding the fire and admitting air in the vertical
side or face of the furnace above the doorway or "glut," herein-before
described; or this secondary opening may be made in an inclined curved
portion of the brow of the furnace or bench, so that the fuel can be intro-
duced laterally, provided it is not directly above or over the fire, the opening
usually made in the latter position being of course closed, if the improvement
is applied to old kilns, or the top of the furnace being made solid-and-without
an opening if the kiln is being newly erected. The secondary feeding and
air opening may be furnished with any convenient kind of doors, or doors for
closing it, or for regulating the admission of air, and it may either constitute
a separate opening in the brickwork, or it may form the upper portion, or an
upward extension of the large doorway or "glut," such doorway being of
course built up only to the level of the doors, fitted to the upper portion
thereof. Amongst other advantages, this arrangement permits of a direct
inspection of the flues whilst the burning is going on, which cannot be so
easily effected through the ordinary opening in the top of the furnace. The
admission of air is also more easily regulated by means of the doors of the
lateral opening, without the necessity of constantly renewing the doors or
other closing details, as is the case with the top opening, from these being
rapidly burnt away by the action of the fire.. It is preferred to apply double
doors to the opening, so that when they are more or less open the opening is
always in the centre of the furnace.
As regards the other details of the furnaces and kilns, any of the various
arrangements in use may be adopted. The furnaces may be made, with or
without ash-pits and furnace bars, the use of ash-pits and furnace bars being
preferred; and it being also preferred to incline, the bars upwards towards the
back end of the furnace. An important advantage of the improved system
of construction is in the increased, durability of the furnace mouth,, which
<does not require repairs nearly so soon as with the ordinary, arrangement.
The of smoke from the furnace mouth, is also quité done, away, with,
egress

page_text: contributing greatly to the comfort of the workmen and to the cleanliness of
the place, inasmuch that the kiln may be whitewashed externally without
chance of being discolored.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Hannah in the Great Seal Patent Office on the
10th September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
HANNAH, of Glasgow, in the County of Lanark, North Britain, Pottery.
Manager, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of March, in the year of our Lord One
thousand eight hundred and fifty-six, in the nineteenth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said.
Robert Hannah, Her special license that I, the said Robert Hannah, my
exccutors, administrators, and assigns, or such others as I, the said Robert
Hannah, 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 Invention for "IMPROVEMENTS IN
POTTERY KILNS," upon the condition (amongst others) that I, the said Robert
Hannah, 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 Robert Hannah, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
in writing, reference being had to the accompanying Drawings, and to letters
and figures marked thereon, that is to say :-
My said Invention relates to the so arranging and constructing the furnaces
of "biscuit," " gloss," and other kilns or ovens for burning, "hardening," and
enamelling pottery ware, or earthenware, as to secure increased economy in the
consumption of fuel, and a saving of expense in repairs, together with other
practical advantages.
Kilns of the class to which this Invention refers are generally made cir-

page_text: cular in plan, and the furnaces are placed in an enlargement of the structure,
running round the lower part of the circumferential wall of the kiln chamber,
such enlargement forming a step or bench, as it were, round the wall, with a
flat top and with vertical sides. A "glut" or doorway is usually formed for
each furnace in the vertical face of the wall for clearing out the furnace, and
this doorway is built up and closed when the kiln is in operation. In addition
to this side door, there is usually an opening in the top of the furnace in that
part which forms the horizontal top of the step or bench, which opening is for
feeding the fire by and for admitting air. It it found, however, in practice
that the top opening is the cause of a great waste of fuel, as much smoke
and heated gases escape thereat; and as it necessary to use large pieces of
coal to insure the proper action of the fire, and to regulate the access of
the air thereto, as is well understood by the practical pottery manufacturer.
Now, the present Invention consists, according to one modification, in form-
ing this secondary opening for feeding the fire and admitting air in the vertical
side or face of the furnace above the doorway or "glut," herein-before
described; or, this secondary opening may be made in an inclined or curved
portion of the brow of the furnace or bench, so that the fuel can be intro-
duced laterally, provided it is not directly above or over the fire, the opening
usually made in the latter position being of course closed if the improvement
is applied to old kilns, or the top of the furnace being made solid and without
an opening if the kiln is being newly erected. The secondary feeding and air
opening may be furnished with any convenient kind of door or doors, for
closing it, or for regulating the admission of air, and it may either constitute
a separate opening in the brickwork, or it may form the upper portion or an
upward extension of the large doorway or "glut," such doorway being of
course built up only to the level of the doors, fitted to the upper portion
thereof. Amongst other advantages, this arrangement permits of a direct
inspection of the flues whilst the burning is going on, which cannot be so
easily effected through the ordinary opening in the top of the furnace. The
admission of air is also more easily regulated by means of the doors of the
lateral opening, without the necessity of constantly renewing doors or
other closing details, as is the case with the top opening, from these being
rapidly burnt away by the action of the fire. It is preferred to apply double
doors to the opening, so that when they are more or less open the opening is
lways in the centre of the furnace.
As regards the other details of the furnaces and kilns, any of the various
arrangements in use may be adopted. The furnaces may be made with or
without ash-pits and furnace bars, the use of ash-pits and furnace bars being

page_text: preferred, and it being also preferred to incline the bars upwards towards the
back end of the furnace. An important advantage of the improved system
of construction is in the increased durability of the furnace mouth, which does
not require repairs nearly so soon as with the ordinary arrangement. The
egress of smoke from the furnace mouth is also quite done away with,. con-
tributing greatly to the comfort of the workman and to the cleanliness of the
place, so much so indeed that the kiln may be whitewashed externally without
chance of being discoloured.
And in order that my said Invention may be properly understood, I have
O hereunto appended and shall now proceed to describe a Sheets of explanatory
Drawings, showing a mode of working out my Invention in practice.
Figure 1, on the Sheet of Drawings, is a partially sectioned elevation of a
pottery kiln, the furnaces of which are constructed according to my improved
system; Figure 2 is a plan of the kiln, showing portions as sectioned hori-
zontally at different levels.
The kiln represented in the Drawings is circular in plan, and is fired by
means of nine furnaces A, placed equidistantly round it. Each furnace A is
formed through the wall B of the kiln, and through the bench or step C,
passing round the lower part of the wall. In this instance the brickwork
casings of the furnaces rise above the top of the bench C. The covering
arch D of each kiln extends from the inside of the wall quite to the front of
the furnace, and in the front vertical face of the furnace is the usual arched
glut or doorway E, through which the furnace is cleared out, this glut being
built up when the furnace is in operation. Immediately above this glut E is
5 a furnace doorway F, fitted with two hinged furnace doors G, and entering
the furnace horizontally. It is in the arrangement of this doorway F that the
improvement constituting the present Invention mainly consists; through it i
the furnace is supplied by fuel, and by it also may air be admitted, whilst
the emission of flames and smoke and consequent waste of fuel with the
ordinary arrangement of feeding doorway or aperture is prevented. The con-
struction of the flues for conducting the flames and heated gases from the
furnaces into the kiln chamber may be according to any of the systems in use.
In the kiln represented in the Drawings a portion of the flames pass along
a series of flues I running under the flooring I of the kiln chamber, whilst
another portion issues into the kiln chamber by bag flues J. Openings K are
made through the wall B into the bag flues J for the admission of air, if
necessary, such apertures being closed, or more or less opened, by means of
a brick L, or in any other convenient manner Other apertures M are also
formed through the wall B, just over the mouths of the bag flues J, to form

page_text: The
sight holes for the inspection of the interior of the kiln chamber.
furnaces are represented as formed with ash-pits N, the mouths of which
are partially or wholly covered by plates O, air being admitted beneath the fire
bars by uncovering the mouth of the ash-pits more or less. The fire bars P of
the furnaces are represented as inclined upwards towards the inner ends of the
furnaces, an arrangement which I prefer, although any other suitable plan may
be adopted in combination with my improved arrangement of the .feeding
aperture F. This last remark applies also to the various details of the kiln, that
is to say, various modifications of the several details of the kiln may be adopted
in combination with my improved arrangement of the feeding aperture.
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 within
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 by the herein-before in part recited Letters Patent, is, the system
or mode of arranging and constructing the furnaces of "biscuit," "gloss," and
other kilns or ovens for burning, "hardening on," or enamelling pottery or
earthenware, wherein the feeding aperture or doorway for supplying fuel and
admitting air enters the furnace in a horizontal or nearly horizontal direction;
being formed through the front or side wall of the furnace, as herein-before
described.
In witness whereof, I, the said Robert Hannah, have hereunto set my
hand and seal, this Eighth day of September, One thousand cight
hundred and fifty-six.
ROBERT HANNAH. (L.s.)