IMPROVEMENTS FOR ADMITTING AIR TO THE FURNACES OR FIRE-BOXES OF STEAM BOILERS OR OTHER HEAT GENERATORS
Year: 1875

page_text: LETTERS PATENT to James Stone, of 167, Gray's Inn Road, London,
Gentleman, for the Invention of "IMPROVEMENTS FOR ADMITTING AIR
TO THE FURNACES OR FIRE-BOXES OF STEAM BOILERS OR OTHER HEAT
GENERATORS."
Sealed the 3rd March 1876, and dated the 26th October 1875.
PROVISIONAL SPECIFICATION left by the said James Stone at the
Office of the Commissioners of Patents, with his Petition, on the
26th October 1875.
I, JAMES STONE, of 167, Gray's Inn Road, London, Gentleman,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
FOR ADMITTING AIR TO THE FURNACES OR FIRE-BOXES OF STEAM BOILERS OR OTHER
HEAT GENERATORS," to be as follows:-
:-
This Invention relates to an improved mode of admitting air to the
furnace or fire-box of a steam boiler or other heat generator, and consists
of a metallic or other suitable casing placed round or externally to the
boiler or other generator, a space being left between the latter and the
said casing. The casing is closed, except at the top or other desirable

page_text: part, where circular or other suitably shaped apertures or openings are
formed, through which the air is admitted and passes between the boiler
and casing through the fire-door into the furnace or fire-box, thereby
absorbing in its passage any heat that may be given off from the boiler
and entering the furnace in a heated state instead of cold as when
admitted in the ordinary way.
The boiler or other generator may be coated with some suitable non-
conducting composition or not, as found desirable.
A moveable disc or covering is placed over the said apertures or
openings in the casing, and is operated by a handle or other device so
as to regulate the admission of air at pleasure; or more than one disc
or covering may be used if desired.
The stoking of the boiler is effected by a door formed in the casing.
The advantages of this Invention are that the stoke-hole is kept
noufantly cool and neonomy of fuel is affected
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Stone in the Great Seal Patent Office on
the 25th April 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
STONE, of 167, Gray's Inn Road, in the City of London, Gentleman, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of October, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said James Stone, Her special
licence that I, the said James Stone, my executors, administrators, and
assigns, or such others as I, the said James Stone, 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 FOR
ADMITTING AIR TO THE FURNACES OR FIRE-BOXES, OF STEAM BOILERS OR OTHER

page_text: HEAT GENERATORS," upon the condition (amongst others) that I, the said
James Stone, 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,
3 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 James Stone, 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:-
This Invention relates to an improved mode of admitting air to the
furnace or fire-box of a steam boiler or other heat generator, and consists
of a metallic or other suitable casing placed round or externally to the
boiler or other heat generator, a space being left between the latter and
the said casing. The casing is closed, except at the top or other
desirable part, where circular or other suitably shaped apertures or
openings are formed, through which the air is admitted and passes
between the boiler and casing through the stoke-hole and fire-grate into
the furnace or fire-box, thereby absorbing in its passage any heat that
may be given off from the boiler, and entering the furnace in a heated
state, instead of cold as when admitted in the ordinary way.
The boiler or other heat generator may be coated with some suitable
non-conducting composition or not, as found desirable.
A movable disc or covering is placed over the said apertures or
openings in the casing, and is operated by a handle or other device so as
to regulate the admission of air to the casing at pleasure; or more than
one disc or covering may be used if desired.
The stoking of the boiler is effected by a door formed in the casing.
And in order that the said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the Drawing hereunto annexed, the
same letters of reference indicating corresponding parts in all the corre-
sponding Figures.
Figure 1 represents a front elevation of an upright steam boiler fitted
with my Invention, and Figure 2 a plan thereof.

page_text: A represents a cylindrical casing (shewn partly broken away) composed
of sheet iron or other suitable material, and placed over and entirely
surrounding the boiler B, an annular space a being left between the
said casing and boiler, as shewn. The casing A is in its normal con-
dition completely closed to the atmosphere, except at the top a or other
desirable part, where it is formed with radial (or other suitably shaped)
apertures or openings 1, 1, (Fig. 2) for the purpose of admitting air to
the interior of the casing A or annular space x, as more particularly
herein after described. C is a movable disc or covering formed with
radial (or other suitably shaped) wings or pieces 2, 2, corresponding
with the apertures or openings 1, 1, and capable of being moved over
the same on the top a of the casing A round the chimney or funnel D
of the boiler B as a centre (or otherwise as found most convenient), in
such a manner as to open or close the apertures or openings 1, 1, with
the atmosphere, and so regulate the admission of air to the interior of
the casing A or annular space x to any desirable amount.
In some cases in lieu of the apertures or openings 1, 1, being at the
top a of the casing A, as shewn, they may be arranged near the
upper portion of the vertical cylindrical wall of the casing A, and the
admission of air may be regulated by sliding plates or doors; or the
apertures for the admission of air may be arranged in any other equi-
valent manner that may be found most advantageous. c is a handle
fixed to the movable disc or covering C for the purpose of shifting it so
as to bring the wings or pieces 2, 2, more or less over the apertures or
openings 1, 1, or the same effect may be produced by any other suitable
arrangement of levers or devices.
Immediately opposite to the opening of the fire-door E of the boiler B
(Fig. 2) is a corresponding opening F in the casing A, which opening
is closed by a door G, and through which, as well as through the
opening of the fire-door E, fuel is supplied to the furnace or fire-box of
the boiler B, and the necessary stoking is effected.
In many cases the fire-door E may be dispensed with, and the
intervening portion of the annular space between it and the casing A
occupied by a cylindrical piece or tube y of sheet iron or other material
forming a continuation as it were of the mouth of the fire-box or
furnace, and secured to and fitting closely round the openings of the
fire-doors E and G, as shewn in dotted shaded lines in Figure 2, the
stoking being effected through the fire-door opening F alone. H repre-

page_text: sents an opening in the bottom of the casing A forming an entrance to
the stoke-hole or ash-pit of the boiler B, and opened or closed at pleasuro
by a sliding or other suitably arranged damper or door I, as shewn.
An opening and door K are also formed in the casing A immediately
opposite to the man-hole door of the boiler B, so as to allow of the
removal of the man-hole door when required. The ordinary water
gauge, pressure gauge, and other fittings are extended across the annular
space, and through the wall of the casing A, as shewn. The steam
pipe also passes through the casing A, the safety valve being mounted
in any convenient position on the outside.
The boiler B may or may not be coated with my patent boiler
coating, or with any other suitable non-conducting material z, or with
an air chamber surrounding the skin of the boiler in combination with
the casing A.
In getting up steam, fuel is supplied to the furnace or fire-box of the
boiler B through the openings of the fire-doors E, G, as described (or
through the opening of the door G alone when the door E is dispensed
with), and the said doors being then closed the door or damper I of the
entrance H to the stoke-hole or ash-pit of the boiler B is opened to assist
the draught until the lighted fuel is in a thorough state of incandescence
or combustion, when the door or damper I is closed and the movable
dise or covering C is adjusted by its handle c, so as to admit air through
the apertures or openings 1, 1, in the top a of the casing A, the air
having no other inlet to the fire-box or furnace is compelled to traverse
the whole length of the boiler B along the annular space a, and through
the stoke-hole or ash-pit and fire-grate into the furnace; in so doing
the heat radiated or given off from the surface of the boiler B (or from
the coating or air chamber by which it is surrounded, as the case may
be) is more or less absorbed or taken up by the draught, which thereby
passes into the fire-box or furnace in a more or less heated state.
Amongst some of the advantages of this Invention are that the stoke-
hole is kept comparatively cool (a great desideratum in the case of its
application to marine boilers) and economy of fuel is effected, radiation
being reduced to a minimum.
Figures 3 and 4 represent my Invention applied to a horizontal flue
boiler set in brickwork, in which case the casing A¹ instead of entirely
surrounding the boiler B¹ is confined to that portion of it which is

page_text: exposed to view, a space x' being left between the boiler B₁ and
casing A', along which the air passes to the furnace in a similiar manner
to that already described in Figures 1 and 2.
This Invention is applicable to locomotive and marine boilers and
other boilers, and generally to all furnaces, vessels, or apparatuses where
fuel is burnt for the generation of heat.
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 would observe in conclusion that what I consider to
be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,-
First. The combination with steam boilers of an external casing
applied so as to form a heating chamber, substantially as and for
the purpose berein-before described and illustrated by the accompanying
Drawing.
Secondly. The application and use of an external casing in com-
bination with a steam boiler covered with a suitable non-conducting
material, the casing being so applied as to form a heating chamber for
heating air supplied to the furnace, substantially as and for the purpose
herein-before described and illustrated by the accompanying Drawing.
In witness whereof, I, the said James Stone, have hereunto
set my hand and seal, this Seventh day of April, One thousand
eight hundred and seventy-six..
Signed, sealed, and delivered, by the
above-named James Stone, in the
presence of
DANIEL WARDE,
Clerk to Mr. G. J. Brownlow,
Solicitor,
34, Bedford Row,
London.
JAMES STONE. (L.S.)