IMPROVEMENTS IN KILNS, OVENS, OR FURNACES
Year: 1855

page_text: LETTERS PATENT to John Gedge, of No. 4, Wellington Street South,
Strand, in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN KILNS, OVENS, OR FURNACES."-A communication from
Pierre Michel Roy and Edme Joseph Desmergée, both of Saint Verain,
France.
Sealed the 12th January 1856, and dated the 31st August 1855.
PROVISIONAL SPECIFICATION left by the said John Gedge at the Office
of the Commissioners of Patents, with his Petition, on the 31st August
1855.
I, JOHN GEDGE, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN KILNS, OVENS, OR FURNACES," communicated to me by Pierre
Michel Roy and Edme Joseph Desmergée, both of Saint Verain, "France,"
to be as follows:-
I propose, instead of the kiln, oven, or furnace in ordinary use for making
earthenware, bricks, or lime, to use one which will uniformly disperse
caloric and save the pottery from contact with the flame, that will effect
economy in the manufacture, and produce articles of superior quality. The
lower part of the oven will differ little in its form from that in ordinary use,
but above its roof is constructed another and smaller oven (when pottery
is made), in which objects not requiring intense heat are to be placed. The

page_text: roof of the lower oven is pierced with holes to allow the ascent and dispersion
of caloric into the upper oven, and holes (with covers) are made in the roof of
the smaller oven to effect the withdrawal of the goods. When no bricks are
to be baked in an operation, I propose to place refraction bricks, so that
channels shall be left between them. These channels are also covered with
bricks, but in such manner as to leave many openings. I also propose to use
gratings at the mouth, and on part of the floor of the oven.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by, the said John Gedge in the Great Seal Patent Office on the 25th
February 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GEDGE, of Number Four, Wellington Street South, Strand, in the County of
Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of August, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Gedge, Her especial license that I, the said John Gedge, my
executors, administrators, and assigns, or such others as I, the said John
Gedge, 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, OVENS, OR
FURNACES," being a communication from Pierre Michel Roy and Edme Joseph
Desmergée, both of Saint Verain, France, upon the condition (amongst others)
that I, the said John Gedge, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, 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 John Gedge, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed:-
The imperfection of pottery kilns or furnaces in ordinary use having long

page_text: attracted attention, this Invention is an endeavour to improve the action
thereof. After many experiments, extending over a lapse of years, this im-
proved kiln is constructed without any considerable departure from the ordinary
construction, but gives very advantageous results both as to the quality of
manufacture and saving of cost. The principal object of this kiln is the baking
of pottery, the burning of bricks and lime being simply an appendage or
accessory thereto. The presence of the latter articles in this system is for the
purpose of using and uniformly distributing the caloric, and to preserve
the pottery from direct contact with the flame, which under the ordinary
system occasions considerable waste, or from the cinders and dirt which
escaping from the furnace attach to the objects in process of baking, thereby
augmenting a waste usually equal to one-fifth of the manufacture. Above,
upon, and connected with this kiln is placed another and smaller kiln (shewn
at Figure 3), adapted to the baking of biscuit, such as feet warmers, flower
pots, and other articles not requiring extreme heat in the manufacture. This
kiln differs from the ordinary kiln, being longer, and by the addition of a
furnace grating, and of a place for receiving the lime and bricks. That part
of the arch upon which the second and smaller kiln rests is pierced with
fourteen holes, of two inches and a quarter (or thereabouts) in diameter,
permitting the caloric to ascend and disperse through its interior, baking the
objects enclosed. Six holes, of about one and a half inches in diameter, are also
left in the arch of the smaller kiln, furnished with a cover, by which the with-
drawal is regulated. The second improvement is in a disposition of conduits
serving (should there be no bricks to burn) to divide the flame. This is done
by piling fire bricks one above the other, until raised a little above the floor of
the kiln, leaving between them passages or conduits of about eleven inches by
five at the entry of the flame, by about seven inches by six at its exit, which is
also covered by bricks, between which are left numerous interstices. This
species of grating, disposed in the manner indicated by the Drawing, máy
be left indefinitely, and will give to the entire kiln a well-regulated heat.
Figure 1 represents a vertical and longitudinal section, taken through the
centre of the kiln; Figure 2, a horizontal section, shewing a plan of the grating
and of the biscuit kiln; and Figures 3 and 4, transverse and vertical sections,
taken through the centre of the grating and of the biscuit kiln. The grating
of the furnace, either of iron or brick, is pierced with square holes, about two
inches apart; this description of grating will not permit the fuel to fall into
the ash-pit until its combustion has taken place. In ordinary kilns the fuel
thrown in at the door falls almost immediately into the ash-pit, or, deprived of
air from beneath, combustion is difficult, and a great part of the caloric is lost;

page_text: in such kilns the opening is necessarily large, thereby lessening the draft. At
Figure 1 is seen a limestone arch, roughly made, of dry stone; its weight rests
upon the grating of the furnace, and its upper part upon a shoulder left in the
masonry of the kiln immediately above the door of the furnace. This arch
serves but once, a new one being required for each baking; but, it being trans-
formed by the heat into lime, its sale adds to the profit of the manufacture.
The object of this arch is to prevent the flame from acting directly upon the
upper part of the kiln, which is otherwise (compared with the lower part)
invariably too much heated. In the ordinary kiln, articles placed on the lower
part of the kiln are often but partially baked, while those at the top are burnt.
Small conduits are reserved in the stone for the purpose of repanding the heat
through the thickness of the arch. A range of three large conduits assist the
passage of the flame. At Figures 1 and 4 are seen bricks submitted to
the furnace; these bricks dovetail into each other, but numerous interstices
are left, between which the flame circulates before arriving at that part of the
kiln reserved for potteries. These bricks thus placed form a species of grating,
and arrest in their passage the dirt and cinders, which often escape with the
flame, and in ordinary kilns attach to the wares, and thus deteriorates them.
Should no market be found for these bricks, they can remain in the furnace,
and will serve several years.
In witness whereof, the said John Gedge hath hereunto set his hand
and seal, this Twenty-third day of February, in the year of our Lord
One thousand eight hundred and fifty-six.
Witness,
W. E. GEDGE,
4, Wellington St., Strand, London.
JOHN GEDGE. (L.S.)