IMPROVED APPARATUS FOR CONSUMING SMOKE
Year: 1853

page_text: LETTERS PATENT to John Gray, of Rotherhithe, in the County of
Surrey, Engineer, for the Invention of "IMPROVED APPARATUS FOR
CONSUMING SMOKE."
Sealed the 22nd September 1858, and dated the 1st August 1853.
PROVISIONAL SPECIFICATION left by the said John Gray at the
Office of the Commissioners of Patents, with his Petition, on the
1st August 1853.
I, JOHN GRAY, do hereby declare the nature of the said Invention
for "IMPROVED APPARATUS FOR CONSUMING SMOKE" to be as follows:-
I construct the bridge behind the fire grate with a passage or
passages, through which a portion of the flame or products of com-
bustion pass from the upper surface of the fire, and with another
passage or passages for the introduction of air. These last passages
convey the air to the first passages through which the products of
combustion pass, and the air is thus mingled with the products of com-
bustion, and escapes through one or more apertures in the bridge, and
meets with the remaining portion of the products of combustion which
passes over the bridge. The air may enter the bridge from the ash pit
or it may be conveyed to the interior of the bridge by means of pipes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Gray, in the Great Seal Patent Office,
on the 31st January 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN GRAY, late of Rotherhithe, in the County of Surrey, but now of
Peckham, in the same County, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of August, in the year of
our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Gray, Her special licence
that I, the said John Gray, my executors, administrators, and
assigns, or such others as I, the said John Gray, 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, usc, ex-
ercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVED APPARATUS FOR CONSUMING SMOKE," upon the condition (amongst
others) that I, the said John Gray, 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 John Gray, 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, reference being had to the accom-
panying Drawing, and to the figures and letters marked thereon, that is
to say:
The Invention consists in constructing the bridges or back parts of

page_text: furnaces with two passages or sets of passages communicating with
cach other, and with a common chamber or passage for the admission
of air, and arranged as herein-after described.
Figure 1, is a longitudinal section, and Figure 2, is a transverse
section of a furnace constructed according to my Invention, and applied
to the heating of a steam boiler. The same letters refer to similar
parts in each Figure. A, is the boiler; B, is the grate; and C, is the
bridge; D, is the brickwork setting of the boiler.
The bridge C, is made of fire brick or other suitable material, sup-
ported on a cast iron plate E, beneath which is the vertical plate F,
having an aperture with a valve or damper G. II, is a wall or mass of
brickwork beyond the bridge C; and I, is a slit or series of openings
between the brickwork H, and the bridge C; K, K, are other openings
through the bridge into the furnace. The openings I, and K, com-
municate with the chamber I, into which air enters at the valve G.
.
The action of the apparatus is as follows:-A fire of coal is made on
the grate B, and a portion of the products of combustion passes over
the bridge, while another portion passes through the openings K, K, and
meeting with a current of air entering at the valve G, the hot mixture
so produced passes up through the slit or openings I, and meets the
first portion of the products of combustion, which is passing over the
bridge. The unconsumed gases are thus ignited, and I find that the
combustion is more perfect than when cold air is simply admitted at
the slit I, as in some of the smoke-consuming furnaces heretofore used.
By opening the valve G, to its full extent a portion of the air passes
through the openings K, into the furnace, the remainder passing
through the slit or openings I, in which case I find it advantageous to
heap up the fuel so as to partially cover the openings K, or even
entirely to cover them. By this means a vivid combustion is produced
at or close to the bridge, which acquires a high temperature, and the
remaining unconsumed gases in their passage over the bridge come in
contact with the air passing through the openings I, and become ignited.
In whichever manner my apparatus is employed it will be found that
little or no smoke escapes into the chimney, and it is therefore not
absolutely necessary to employ the valve G, as the opening for the
admission of the air may be permanently adjusted, in the first instance,

page_text: to produce the required result. Thus, in Figures 3, and 4, I have
shown the apparatus constructed without the valve, and adapted to a
furnace placed within a steam boiler. Figure 3, is a longitudinal
section, and Figure 4, is a transverse section. A, is the outer shell of
the boiler; M, is the flue or tube which contains the grate B, bridge
C, and wall H; E, is the plate which supports the bridge; and F, is
the vertical plate beneath it. This plate does not reach to the bottom
of the tube M, but is cut off to leave a space G, for the entrance of the
air. The other parts are similar to those similarly marked in Figures
1, and 2. The ends of the grate bars B, pass under the plate E,
which arrangement is advantageous in cases in which grate bars
having a reciprocating end motion are employed.
I have shewn my apparatus as adapted to steam boilers, but it is
obvious that it is also applicable to brewers' coppers, bakers' ovens,
reverberatory furnaces, and many other descriptions of furnaces.
Having now described the nature of my Invention, and in what
manner the same is to be performed,. I wish it to be understood that
I do not claim generally the admitting of air at the bridge of a furnace;
but what I claim is, the constructing the bridges or back parts of
furnaces with two passages or sets of passages communicating with
each other and with a common chamber or passage for the admission
of air, and arranged in manner herein-before described.
In witness whereof, I, the said John Gray, have hereunto set
my hand and seal, this Thirty-first day of January, in the year
of our Lord One thousand eight hundred and fifty-four.
Witness,
CHARLES COWPER,
20, Southampton Buildings,
Chancery Lane.
JOHN GRAY. (L.S.)