IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES, AND IN THE MRANG
Year: 1874

page_text: LETTERS PATENT to Henry Hathaway, Manager of the Gas Works,
North Shields, in the County of Northumberland, for the Invention
of “IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES, AND IN THE
MRANG C
Scaled the 18th September 1874, and dated the 25th March 1874.
PROVISIONAL SPECIFICATION left by the said Henry Hathaway.at
the Office of the Commissioners of Patents, with his Petition, on
the 25th March 1874.
I, HENRY HATHAWAY, Manager of the Gas Works, North Shields, in
5 the County of Northumberland, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES, AND
IN THE MEANS OF SUPPLYING AIR THERETO," to be as follows:-
This Invention relates to the construction of boiler furnaces in such a
manner that the air necessary to support combustion shall be heated

page_text: thereby before entering the fire, and consists in closing in not only the
upper part of the furnace tube, but also the lower part, or that forming
the ash-pit, a door being inserted for the removal of ashes. On one or
more sides of the furnace, below the furnace bars, are made openings
that lead the air into pipes or conduits, which are carried to or through
the bridge to the back of the boiler, and from thence return to within a
short distance of the front of the ash-pit, when the air which has become
heated in its passage will enter the fire from below the bars.
The openings before alluded to may be furnished with dampers or
valves by which the quantity of air admitted to the furnace may be
regulated and the bridge may be made hollow, so as to form a heated
air chamber; and the inlet air pipe may be introduced from the back of
the boiler, and go straight through to the front, instead of going in at
the front and returning as above.
The Invention is applicable not only to Cornish boilers, but to marino
boilers, locomotives, and to those of other form.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Hathaway in the Great Seal Patent Office
on the 22nd September 1874.
:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
HATHAWAY, Manager of the Gas Works, North Shields, in the County
of Northumberland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of March, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Hathaway, Her special
licence that I, the said Henry Hathaway, my executors, administrators,
and assigns, or such others as I, the said Henry Hathaway, 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

page_text: Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE CONSTRUCTION OF FURNACES, AND IN THE MEANS OF SUPPLYING AIR THERETO,"
upon the condition (amongst others) that I, the said Henry Hathaway,
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 Scal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Hathaway, 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 accompanying
Drawings, and to the letters and figures marked thereon, that is to
say :-
This Invention relates to the construction of boiler and other furnaces
in such a manner that the air necessary to support combustion shall be
heated thereby before entering the fire, and consists in closing in not
that
only the upper part of the furnace tube, but also the lower part, or
forming the front of the ash-pit, a door being inserted for the removal of
ashes. On one or more sides of the furnace, below the furnace bars, are
made in the front of the furnace an opening or openings that lead the
air into pipes or conduits, which are carried either as far as thic bridge,
and then return to within a short distance of the front of the ash-pit, or
they may be connected to a hollow bridge; or the pipes or conduits
may be led through the bridge to the back of the boiler, and from thence
return through the bridge to the front, as in the previously-named
agreement, when the air which has become heated in its passage will
enter the fire from below the bars.
Another arrangement consists in making the bridge hollow, so as to
form a heated chamber, and introducing the inlet air pipe from the
back, while one, two, or more pipes are attached to the front of the
bridge, and convey the heated air to or near the front of.the fire.
.
To adapt the Invention to boilers already constructed I. propose to
pass the conduits or pipes through the existing brick bridge, and build
a similar bridge behind it, but leaving a space of about two feet, more
or less. These bridges, when covered in: by tiles or other suitable sub>
.

page_text: stance, will form a heated air chamber from whence the air will pass
to the furnace.
The openings in the front of the boiler before alluded to may be
furnished with dampers or valves by which the quantity of air admitted
to the furnace can be regulated.
In order that the foregoing may be more easily understood Drawings
are attached hereto, of which the following is a description:-
Fig. 1 is an elevation of the front of the boiler; Fig. 2, a vertical
section through C, D; Fig. 3, which is a horizontal section through A, B,
of Figs. 1 and 2, and shows the manner in which the Invention is
adapted to existing boilers, while Fig. 4 is a similar section showing a
different arrangement of air tubes. E is the boiler; F, the furnace
door; G, the ash-pit door; and H, the inlet opening for air; I is the
air tube or conduit, the inlet end being marked H, while the outlet or
delivery end for the heated air is marked J; K is the bridge; O, the
heated air chamber; and L, the furnace bars. In Fig. 4 the bridge K is
made hollow, and the inlet for the air is from the back at M, the delivery
ends being marked J; N is a long narrow door to be used when pricking
up of bar is requisite. The tubes, channels, or conduits in either case
are not limited in number, shape, or size. Similar letters refer to the
same parts in each of the Drawings.
It will be seen, on inspecting the Drawings, that the air enters either
at H or M, and following the direction of the arrows is delivered at a
greatly increased temperature at J.
The Invention is applicable not only to Cornish boilers, but to marine
boilers, locomotives, and to those of other form.
;
Having now described and particularly set forth the nature of this
Invention, and the manner in which the same is or may be used. or
carried into effect, I would observe in conclusion that I do not
confine or restrict myself to the precise details or arrangements which I
have described or referred to, as variations may be made therefrom
without deviating from the principles or main features of this In
vention; but 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, the construction of furnaces with tubes,
channels, or conduits in the manner herein described, and shown on
1

page_text: the Drawings, for the purpose of supplying heated air to the said
furnaces.
In witness whereof, I, the said Henry Hathaway, have hereunto
set my hand and seal, this Twenty-second day of September, in
the year of our Lord One thousand eight hundred and seventy-
four.
HENRY HATHAWAY. (L.S.)