IM- PROVEMENTS IN THE CONSTRUCTION OF STEAM BOILER AND OTHER FURNACES
Year: 1853

page_text: LETTERS PATENT to George Nasmyth, of No. 3, Brabant Court,
Philpot Lane, in the City of London, for the Invention of "IM-
PROVEMENTS IN THE CONSTRUCTION OF STEAM BOILER AND OTHER
FURNACES."
Sealed the 2nd May 1853, and dated the 4th November 1853.
PROVISIONAL SPECIFICATION left by the said George Nasmyth
at the Office of the Commissioners of Patents, with his Petition,
on the 4th November 1853.
I, GEORGE NASMYTH, of 3, Brabant Court, Philpot Lane, in the City
of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILER AND OTHER FUR-
NACES" to be as follows:-
Various means have before been devised for applying heated air at
and beyond the bridges of steam boiler and other furnaces, and different
means of heating the air for such purposes have been suggested and
employed. Now my improvements relate to the construction of furnaces
with a view to heat the requisite supply of air in order to supply the
same at or heyond the bridges of such furnaces. And the improve-

page_text: ments consist of building the two sides of the furnace double, leaving a
hollow chamber on each side of the furnace, which chambers are open
in front, and have doors or regulators to regulate the supply of air
thereto, and the chambers at their back ends communicate with passages
to the hollow bridge or apparatus for distributing the heated air at or
near the bridge. The air in the chambers on either side of the furnace
becomes heated by the fire acting on the fire brick side of the furnace,
which separates the fire from the air chamber, by which means very
large quantities of air can be heated advantageously, & supplied at or
beyond the bridge.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Nasmyth in the Great Seal Patent Office
on the 3d May 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
GEORGE NASMYTH, Civil Engineer, of No. 3, Brabant Court, Philpot
Lane, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing-date the Fourth day of November, 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 the said George Nasmyth Her special licence
that I, the said George Nasmyth, my executors, administrators, and
assigns, or such others as I, the said George Nasmyth, 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
THE CONSTRUCTION OF STEAM BOILER AND OTHER FURNACES," upon-the-con-
dition (amongst others) that I, the said George Nasmyth, by an instru-
ment in writing under my hand and seal; should particularly describe
and ascertain the nature of the said Invention, and in what manner the

page_text: same was to be performéed, 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 George Nasmyth, "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:
My Invention is applicable to furnaces of all descriptions, and has for
its objects the economising. of heat and the prevention of smoke.
The nature of my Invention is as follows:-I make. use of the heat
which in furnaces of ordinary construction passes away into the brick
work, or. sides.of. the furnace, as a means of heating the air. before it
comes in contact with the gases and flame in the furnace or flues. I
accomplish this. by making.ithe sides of the furnace hollow, and by
the formation of a passage in what is called the bridge, which I con-
struct of two separate walls with a space between them. I make the
hot air chambers or passages at the sides of the furnace to communicate
at one end with the open air in the front of the furnace, and at the
other end with the passage between the walls of the bridge before
alluded to. This passage is covered with iron plates, tiles, bricks, or
other
suitable materials furnished with holes or openings so as to allow
'the heated air from the side chambers to pass through and combine
with the flame and unconsumed gases as they pass over the bridge,
and thus cause the smoke to be consumed, or, more correctly, prevent
its formation. In some cases I divide the passages longitudinally or
otherwise, with the view to cause the heated air to act more or less
effect upon various parts of the furnace or flues. I sometimes introduce
the heated air into the furnace through holes or openings in the front
wall of the bridge, and sometimes also through holes or openings in
various parts of the inner wall of my hot air passages or chambers, so
as to accommodate the supply of heated air to the shape of the furnace,
or to other peculiarities connected therewith.
In the accompanying Drawings the corresponding parts are marked
with the same letter, so that the following description will apply to all
the Drawings equally.

page_text: A, the fire grate; B, the flue; C, the hot air passages or chambers;
D, D, the walls of the bridge; E, the perforated cover of the passage
in the bridge.
What I particularly claim as my Invention is, the use of hollow
passages or chambers at the sides of the furnace, and communicating
therewith by means of the passage through the bridge or otherwise, as
above described, and for the purposes above referred to; but I do not
confine myself to any specific forms or dimensions, nor to the use of
any special materials, but claim to make such chambers or passages of
such size and shape and of such materials as may be found most suit-
able in each particular case to which my Invention is or may be applied;
nor do I confine myself to any special form or position of the holes
or openings, but claim to introduce the hot air from my passages
or chambers through holes or apertures into any such part or parts of
the furnace or flues as may seem most convenient in each particular
instance.
In witness whereof, I, the said George Nasmyth, have hereunto
set my hand and seal, this First day of May, in the year of our
Lord One thousand eight hundred and fifty-four.
GEORGE NASMYTH. (L.S.)