IMPROVEMENTS IN.. FURNACES
Year: 1868

page_text: LETTERS PATENT to Jonathan Mitchell, of Bradford,. in. the County
of York, Contractor, for the Invention of "IMPROVEMENTS IN..
FURNACES."
Scaled the 22nd December 1868, and dated the 24th June 1868.
PROVISIONAL SPECIFICATION left by the said Jonathan Mitchell at
the Office of the Commissioners of Patents, with his Petition, on the-
24th June 1868...
I, JONATHAN MITCHELL, of Bradford, in the County of York, Con-
tractor, do hereby declare the nature of the said Invention for "IMPROVE--
MENTS IN FURNACES," to be as follows:-
This Invention relates to furnaces or fire-places of steam boilers,.
dyeing vessels, puddling furnaces, and other like purposes where coal
is employed for the fuel, and my object is to economise the fuel and
consume the smoke arising from the combustion thereof or to prevent its
escape into the atmosphere, and the improvements consist in a method

page_text: of combining or constructing and arranging such furnaces of fire-brick
and common brick braced and held together by straps or bars and rods
or bolts of iron, and as applied to steam boilers in being placed at the
end thereof and communicating with the flue or flues. I employ plain
bar iron for grate bars, or bars cast parallel to be supported on bearers so
that they may be readily drawn out endwise for cleaning the furnace
and then replaced. At the outer end of this furnace above the grate
bars I place a dead plate or plate to receive the supply of coal which
is pushed forward into the furnace by the attendant as required, and
space is left betwixt this plate and the grate bars for the introduction
of the rake or poker to regulate the fire. The sides of these furnaces I
line with perforated fire-bricks, leaving a flue behind them open to the
atmosphere, so that air may pass freely through the perforations into
the furnaces. I also form a flue or space in the top part of the furnace
or leave a space above the fire-brick lining of the top which is open
to the furnace at the back end intended to collect the heat passing
through the lining and return it to the furnace or the flues. An
ordinary fire-brick bridge is placed at the back of the furnace, and
in front of which and between the ends of the grate bars is an opening
provided with door or cover to be opened or closed for the admission
or exclusion of air as required.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jonathan Mitchell in the Great Seal Patent
Office on the 24th December 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JONATHAN 2
MITCHELL, of Bradford, in the County of York, Contractor, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of June, in the year
of our Lord One thousand eight hundred and sixty-eight, in the
thirty-second year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Jonathan Mitchell, Her
special licence that I, the said Jonathan Mitchell, my executors,
administrators, and assigns, or such others as I, the said Jonathan

page_text: Mitchell, 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 FURNACES," upon the condition (amongst others)
that I, the said Jonathan Mitchell, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, 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 Jonathan Mitchell, 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 and accompanying Sheet of Drawings
(that is to say) :-
This Invention relates to furnaces or fire-places of steam boilers,
dyeing vessels, puddling furnaces, and other like purposes where coal
is employed for the fuel, and my object is to economise the fuel and
consume the smoke arising from the combustion thereof or to prevent
its escape into the atmosphere, and the improvements consist in a
method of combining, constructing, and arranging such furnaces of
fire-brick and common brick braced and held together by straps or
bars and rods or bolts of iron. At the outer end of this furnace above
the grate bars is placed a dead plate to receive the supply of coal, which
is thence pushed forward into the furnace by the attendant as required,
and space is left betwixt this plate and the grate bars for the intro-
duction of the rake or poker to regulate the fire. The sides of these
furnaces are by preference lined with perforated fire-bricks, leaving
the flue behind them; a flue or space is also formed in the top part
of the furnace with one or more openings to the furnace at the back
end, which space is intended to collect the heat passing through the
lining and return it to the furnace or the flues. An ordinary fire-brick
bridge is placed at the back of the furnace, and in front of which and
between the ends of the grate bars is an opening or chamber provided.

page_text: with an inclined fire-brick cover and a door to be opened or closed
for the admission or exclusion of air, or pipes may be introduced for
conducting air into the said chamber as required.
In order that this Invention may be clearly understood I herein
give reference to the accompanying Sheet of Drawings shewing how
the same is or may be carried into practical operation.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is the longitudinal section of a portion of a steam boiler
"with my improved furnace applied thereto, and Fig. 2 is the end
elevation of same.
A is a portion of a Cornish or ordinary two-flued boiler to the front
of and partly into the flues of which my furnace is fixed; B are the
dead plates which recieve the supply of fuel, the inner end of which
plate is formed hollow so that water may circulate through it to prevent
burning thereof; C are the gratings or grate bars, which may be either
of plain bars of iron or a series cast together, or bars of the ordinary con-
struction; D is a door to introduce the rake or poker; E are the
perforated fire-brick sides of the furnace; F is a fire-brick quarry or
slab placed on bearers at an incline betwixt the back ends of the grates
and the bridge G, leaving a space H. Under this slab is a chamber into
which air passes through pipes I, and a door J may be opened to admit
of an increased quantity of air to the chamber when and if desirable
to be introduced. K are spaces formed in the tops of the furnaces with
the openings L thereto; M are the straps or bars and N the bolts for
holding the brickwork of the furnace together.
Fig. 3 shews the application of this furnace to a dyeing vessel or pan;
Fig. 4 the application thereof to a puddling furnace; and Fig. 5 shews
how it may be applied to a brick kiln.
Having thus described the nature of my said Invention, and shewn
by Drawings how the same is to be performed or carried into practical
effect, I would have it understood that I do not confine myself to the
precise details which I have had occasion to shew and describe herein,
as the same may be varied or modified without departing from the
essential features thereof, nor do I claim the whole of the parts of
which 'the said furnaces are composed separately considered; but what
I do claim as of my Invention is the combination, construction, and

page_text: arrangement of furnaces substantially as herein described and shewn
in the accompanying Sheet of Drawings.
In witness whereof, I, the said Jonathan Mitchell, have hereunto
set my hand and seal, this Sixteenth day of December, in the
year of our Lord One thousand eight hundred and sixty-eight.
Signed, sealed, and delivered by
the within-named Jonathan
Mitchell, in the presence of
GEORGE HEATON.
JONATHAN MITCHELL. (L.S.)