AN IMPROVEMENT IN STEAM BOILER AND OTHER FURNACES."
Year: 1857

page_text: LETTERS PATENT to Robert James Hendrie, junior, of Blossom Street,
Norton Folgate, in the City of London, Silk Dyer, for the Invention of
"AN IMPROVEMENT IN STEAM BOILER AND OTHER FURNACES."
PROVISIONAL SPECIFICATION left by the said Robert James Hendrie
at the Office of the Commissioners of Patents, with his Petition, on the
25th May 1857.
I, ROBERT JAMES HENDRIE, junior, of Blossom Street, Norton Folgate, in
the City of London, Silk Dyer, do hereby declare the nature of the said
Invention for "AN IMPROVEMENT IN STEAM BOILER AND OTHER FURNACES," to be
as follows:-
The object of this Invention is to render the combustion of fuel in close
furnaces more perfect than heretofore. To this end I conduct currents of
heated air from the front of the furnace to the front and rear of the bridge,
and cause the same to mingle with the flame and gases of combustion, and
thereby prevent the passage of smoke from the fire-place. The air flues I
prefer to make of cast or wrought iron, and to protect them with brick, but
they may be formed in the walls of the furnace if desired. At either side of
the furnace I place or form one or more of these air pipes or flues, which
extend from the front of the furnace to the bridge. The outer ends of these
pipes or flues I fit (if required to regulate the amount of air supplied to the
furnace) with doors or valves; and at or near their inner ends I form outlet.

page_text: passages, which are so located as to direct the air which is drawn into the air
pipes or flues across the flame in front of the bridge, and in the like direction
at the back of the bridge. I prefer to make the air exit passages at the back
of the bridge of larger capacity than those in front thereof, so that the air flues
(one or both at each side) will conduct two currents of air into the flame and
heated gases, the currents at the back of the bridge being greater than those
thrown in front thereof.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filod
by the said Robert James Hendrie in the Great Seal Patent Office
on the 25th November 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
JAMES HENDRIE, junior, of Blossom Street, Norton Folgate, in the City of
London, Silk Dyer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of May, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Robert James Hendrie, Her special license that I, the said Robert
James Hendrie, my executors, administrators, and assigns, or such others
as I, the said Robert James Hendrie, 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 yend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "AN IMPROVEMENT IN STEAM BOILER AND OTHEE FURNACES,"
upon the condition (amongst others) that I, the said Robert James Hendrie,
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 Robert James Hendrie, 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, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-

page_text: The object of this Invention is to render the combustion of fuel in close
furnaces or fire-places more perfect than heretofore, and thereby to prevent
the discharge of dense clouds of smoke from their chimney shafts. To this
end I conduct currents of heated air from the front of the furnace to the front
and rear of the bridge, and cause the same to mingle with the flame and gases
of combustion, and thereby prevent the passage of smoke from the fire-place.
In the accompanying Drawing I have shewn in several views my improve-
ments as applied to steam boiler furnaces, and also to the fire-place of a
copper. Fig. 1 is a longitudinal vertical section of a steam boiler furnace
with my improvements applied thereto; Fig. 2 is a sectional plan view, taken
in the line 1, 2, of Fig. 1; and Fig. 3 is a cross section taken in the line 3, 4,
of the same Figure. a is a cylindrical boiler set in brickwork, which forms
the fire-place and a fire-flue c beneath the boiler, which flue branches into
side flues d, d, that connect in the ordinary and well-known manner with the
chimney. In order to prevent the escape of smoke from the furnace, I build
up in the walls of the fire-place air flues e, e*, which may draw air from the
atmosphere at or near the front of the furnace, and discharge it in front and
at the back of the bridge f, which divides the fire-place 6 from the fire flue c.
These air flues I prefer to make of cast or wrought iron, and to protect them
with fire brick, as shewn in the Drawing, or the flues may, if desired, be
formed in the walls of the furnace without the insertion of metallic or other
tubes. By reference to the Drawing it will be seen that there are two
rectangular metallic air flues built into the walls at either side of the furnace,
and that by reason of their extension from the front of the furnace to the
bridge, the temperature of the air admitted to them will be considerably
raised before it is discharged on to the gaseous products of combustion. The
outer ends of these pipes or flues I fit (if required to regulate the amount of
air supplied to the furnace) with doors or valves, and form at or near their
inner ends the outlet or discharge passages. These outlet passages are so
located as to direct the air which is drawn into the air pipes or flues across
the flame in front of the bridge, and in the like direction at the back of the
bridge. I prefer to make the air exit passages at the back of the bridge of
larger capacity in the aggregate than those in front thereof, preferring that
the air flues e and eat each side of the furnace may each conduct two
currents of air into the flame and heated gases at that part, and thus insure a
greater discharge of air at the back of the bridge than in front thereof. The
flues e, e, it will be seen in the detached views Figs. 4, conduct air both to
the back and front of the bridge. By this arrangement I am enabled to
supply to the furnace heated air in such quantity that it will first act upon the

page_text: .
gases of combustion while they are in the fire-place, and then act in a more
energetic manner when the gases have escaped therefrom, and thereby supply
to the ignited gases a sufficient amount of oxygen to insure the combustion of
any solid particles of carbon that may have passed over the furnace bridge.
Fig. 5 shews in cross section a Cornish boiler, with an internal fire-place
fitted with air flues according to my Invention. The air pipes e, e, in this
instance, I convey from the front of the furnace to the bridge through the
water space, and I use either single pipes, one at each side of the fire-place,
to convey currents of heated air to the back and front of the bridge, as before
explained, or pairs of pipes of smaller capacity, as may be thought most
convenient.
Fig. 6 shews in elevation, and Fig. 7 in sectional plan view, (taken in the
line 5, 6, of Fig. 6,) the mode of adapting my Invention to the fire-places of
coppers. In this example it is not usual to employ a bridge, but the rise fin
the brickwork may be supposed to act the part of the bridge, I therefore form
in the side walls air flues e, e, which run from the front of the fire-place to the
back thereof, and have two exit passages for the heated air. These passages,
as in the former examples, direct the air across the flame and gases simul-
taneously and at different points, and thus effect a more perfect combustion of
the fuel than bas heretofore been obtained.
Having now explained the nature of my Invention of "An Improvement in
Steam Boiler and other Furnaces," and described the manner of carrying the
same into effect, I wish it to be understood that I do not claim as of my
Invention, the admission of air to the bridge of furnaces irrespective of the
manner of securing that admission; but what I claim, under the above in
part recited Letters Patent is, arranging air flues for the admission of heated
air to furnaces, in the manner and for the purpose above set forth.
In witness whereof, I, the said Robert James Hendrie, have hereunto
set my hand and seal, the Twenty-fifth day of November, in the year
of our Lord One thousand eight hundred and fifty-seven.
DODED TAXES TENDDIE
TR
ROBERT JAMES HENDRIE
IE, J. (1.S.)