NEW OR IMPROVED APPARATUS FOR PER- FECTING THE COMBUSTION OF FUEL IN THE FURNACES OF STEAM Boilers, and FOR EFFECTING THE BETTER VENTILATION OF STOKE HOLES IN GENERAL, AND OF THOSE OF OVER SEA STEAMERS IN PARTICULAR
Year: 1873

page_text: LETTERS PATENT to John Gray, of Brixton, in the County of Surrey,
Engineer, for the Invention of "NEW OR IMPROVED APPARATUS FOR PER-
FECTING THE COMBUSTION OF FUEL IN THE FURNACES OF STEAM Boilers, and
FOR EFFECTING THE BETTER VENTILATION OF STOKE HOLES IN GENERAL, AND
OF THOSE OF OVER SEA STEAMERS IN PARTICULAR.”
"
Sealed the 4th November 1873, and dated the 5th May 1873.
PROVISIONAL SPECIFICATION left by the said John Gray at the
Office of the Commissioners of Patents, with his Petition, on the
5th May 1873.
I, JOHN GRAY, of Brixton, in the County of Surrey, Engineer, do
hereby declare the nature of the said Invention for "NEW OR IMPROVED
APPARATUS FOR PERFECTING THE COMBUSTION OF FUEL IN THE FURNACES Of Steam
BOILERS, AND FOR EFFECTING THE BETTER VENTILATION OF STOKE HOLES IN
GENERAL, AND OF THOSE OF OVER SEA STEAMERS IN PARTICULAR," to be as
follows:-
This Invention relates to new or improved apparatus for perfecting
the combustion of fuel in the furnaces of steam boilers, and for effecting

page_text: the better ventilation of stoke holes in general, and of those of over sea
steamers in particular.
This I accomplish as follows:-I construct an aperture in the furnace
front for the admission of air to the interior of the furnace. This
aperture I make (by preference) in the form of a horizontal slot of the
greatest length obtainable in the width of the furnace front, and of a
depth varying (according to the size of the boiler and other circum-
stances) from one inch upwards. On the inner side of the furnace door
and directly over the said slot I fix a chamber of metal or other suitable
material, open at both ends, the opening at that end attached to the
furnace front corresponding with the size of the slot therein, whence
the said chamber tapers towards its inner end, so as to reduce the size
of the air passage at its innermost extremity to a half inch, more or less.
The inner end of this chamber is also turned in an upward direction, so
as to bring the mouth of the air passage into a horizontal position, or
nearly so, enabling it to be acted on by a jet of steam in the following
manner :-I convey steam by means of a pipe from any convenient part
of the boiler into the furnace above the said horizontal slot for the
admission of air, and provide the extremity of the steam pipe within the
furnace with an expanding or fan-shaped mouth piece, the inner end
of which spreads out to the same width as the mouth of the said air
passage, and terminates with a vertical face just in front thereof, and in
such manner that any steam introduced will blow on to and over the
same. The pipe by which the steam is conveyed from the boiler to the
furnace is provided with a cock, so that the admission of steam may be
regulated or shut off as required, and the admission of air is in like manner
regulated by a door covering the said aperture in the furnace front.
When desired this door may be attached in a suitable manner to the
cock of the steam pipe, so that they may be opened and closed
simultaneously.
The action is as follows:- -I turn on a jet of steam, and at the same
time open the air passage. The steam blowing over the inner mouth of
such air passage exhausts the air therefrom, causing a partial vacuum
therein, the air from which is immediately replaced from the external
atmosphere, which latter portion is in its turn forced or drawn into the
furnace, thus creating an influx of air in a defined current, which may
be regulated at pleasure (by controlling the admission of steam) and
be impelled either directly on to the fuel or towards any given point in.

page_text: the furnace. For example, I have found it very advantageous to direct
it towards the top of the bridge of the furnace. By the use of this
apparatus the combustion of fuel will be found to be greatly improved,
and as the air introduced will be drawn from the stoke hole, which air
must in its turn be replaced by fresh air from the external atmosphere,
the stoke hole will be thus efficiently ventilated.
This apparatus may be used simply as a blast on the upper surface
of the fuel, as above described, or may be employed for regulating the
draught to both the under and upper surfaces thereof, and thus enabling
the two to be exactly regulated to suit one another.
In the latter case the mouth of the ash-pit is closed, and an apparatus
similar to that above described applied thereto, the dimensions of which
are regulated in relation to the apparatus acting on the upper surface of
the fuel according to varying circumstances.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Gray in the Great Seal Patent Office on the
5th November 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GRAY, of Brixton, in the County of Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of May, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Gray, Her special license 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 law-
fully 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 "NEW OR IMPROVED APPARATUS FOR PERFECTING THE COMBUSTION
OF FUEL IN THE FURNACES OF STEAM BOILERS, AND FOR EFFECTING THE BETTER
VENTILATION OF STOKE HOLES IN GENERAL, AND OF THOSE OF OVER SEA STEAMERS
IN PARTICULAR," upon the condition (amongst others) that I, the said John

page_text: Gray, 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 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, that is to say :-
This Invention relates to new or improved apparatus for perfecting the
combustion of fuel in the furnaces of steam boilers, and for effecting the
better ventilation of stoke holes in general, and of those of over sea
steamers in particular.
And in order that my Invention may be clearly understood and readily
carried into effect I will proceed to describe the same with the aid of the
accompanying Drawings, reference being had to the letters and figures
marked thereon, and in which Figure 1 is a front elevation of my appa-
ratus, Figure 2 is a plan, Figure 3 a transverse vertical central section,
Figure 4, a front elevation of a steam boiler shewing the apparatus
attached, and Figure 5, a vertical section taken at the line a, b, Figure 4.
In each Figure the same letter of reference wherever it occurs indicates
like or corresponding parts.
I form a horizontal slot in the furnace front A above the door of the
greatest length obtainable in the width of the furnace front, and of a
depth of from two to three inches more or less. Through this slot I
insert the two chambers B and C, as shewn in the sectional view,
Figure 3. These two chambers are either cast in one piece, or are fastened
together by screws or otherwise as shewn at Figure 2, and are formed
with a flange D for bolting the apparatus to the furnace front. The
chamber C, as will be seen on reference to Figure 2, is narrow at that
end which joins on to the flange D, but spreads out at its other extremity
to the full width of the chamber B. This chamber C communicates at
its narrow end through the flange D with a pipe E, which extends
upwards into the steam space of the boiler with which it communicates.
This is clearly shewn in Figures 4 and 5. The chamber B is open at
the front to the atmosphere, and is provided with a lid F, so that it may

page_text: be closed when required, and at its other or inner end is turned up as
shewn at Figure 3.
The action of the apparatus is as follows:-The cock in the pipe E
having been turned on, steam from the boiler will rush down the said
pipe into the chamber C, and out at the long thin slot at its inner
extremity (as indicated by the arrows) in a thin sheet. The steam
thus emerging from the chamber C blows over the inner mouth of the
chamber B, exhausting the air from such chamber and carrying the air
on into the furnace. The air thus exhausted from the chamber B is
replaced by fresh air entering at its front end, the lid F having been
previously opened for that purpose; this air is in like manner carried
forward into the furnace, and thus a continuous volume of air is
carried into the furnace so long as steam is allowed to pass down the
pipe E; this may be shut off when required by the cock in the pipe E.
The air thus admitted consumes the heavy hydrocarbon gases being
evolved from the coal, and thus these gases are converted into immense
volumes of flame giving out great heat, instead of being allowed to pass
up the flue and into the atmosphere as dense, black, and highly offensive
smoke. For convenience of opening the lid F it is attached by a chain
to a short lever connected with the cock in the pipe E, so that the action
of opening the cock will also open the said lid, and they will thus remain
open together and can be closed at the same time and by the one action.
As the air passed into the furnace as above described is drawn from the
immediate vicinity of the front of the furnace it follows that in confined
stoke holes the air thus abstracted will cause it to be effectually venti-
lated, as the air has to be replaced by fresh air entering from the external
atmosphere.
When desired the ash pit of the furnace may be closed and an appa-
ratus or blast similar to that just described attached to the front thereof
for supplying air to the under side of the fuel, and by regulating the
relative sizes of the two apparatus or of the amount of steam and con-
sequently also of air admitted to or by them respectively, almost perfect
combustion of the fuel may be obtained.
Having thus particularly described and ascertained the nature of this
my said Invention, and the manner in which the same is to or may be
performed, I claim as my Invention to be secured by the herein-before
in part recited Letters Patent, the new or improved apparatus for per-
fecting the combustion of fuel in the furnaces of steam boilers and for

page_text: effecting the better ventilation of stoke holes in general and of those of
over sea steamers in particular, substantially as herein-before set forth
and described and illustrated in the accompanying Drawings.
In witness whereof, I, the said John Gray, have hercunto set
my hand and seal, this Fifth day of November, in the year of
our Lord One thousand eight hundred and seventy-three.
Witness,
JOHN W. GRAY,
Offices for Patenting
& Introducing Inventions,
16, Southampton Buildings,
W.C.
JOHN GRAY. (L.S.)