IMPROVEMENTS IN FURNACES AND BOILERS
Year: 1871

page_text: LETTERS PATENT to Donald Munro, of Johnstone, in the County of
Renfrew, North Britain, for the Invention of "IMPROVEMENTS IN
FURNACES AND BOILERS."
Sealed the 22nd September 1871, and dated the 27th March 1871.
PROVISIONAL SPECIFICATION left by the said Donald Munro at the
Office of the Commissioners of Patents, with his Petition, on the
27th March 1871.
I, DONALD MUNRO, of Johnstone, in the County of Renfrew, North
Britain, do hereby declare the nature of the said Invention of “Iм-
PROVEMENTS IN FURNACES AND BOILERS," to be as follows, that is to
say-
This Invention, which relates to improvements in the construction
and arrangement of furnaces such as are used for puddling, boiling,
reheating, and forging iron, scrap furnaces, gas furnaces, and furnaces
used for other purposes, consists in forming the whole or part of the
furnace doors and shell into cells through which water is passed for
the purpose of preventing the rapid wasting of the brickwork and

page_text: metal of which the doors and shell are composed. The water is intro-
duced into the cells or spaces of the furnace door, and passing from
a contiguous cistern or tank this water is caused to pass from the door
casing into a boiler constituting the shell of the fire-grate, as is herein-
before mentioned. The circulation of water through the door casing
and shell of the fire-grate prevents their rapid destruction and avoids
the necessity of frequent renewal, thus effecting considerable economy.
The circulation of the water through the boiler constituting the shell
of the fire-grate has also the effect of keeping it cool and preventing
the "clinker" from adhering thereto, as is found to be the case under
existing arrangements. The front of the boiler constituting the shell
of the fire-grate is provided with a sliding door for the purpose of
admitting air to the fire-grate when its supply from the channels or
chambers of the furnace is cut off. The same sliding door being also
opened whenever it becomes necessary to "draw" the fire-bars.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Donald Munro in the Great Seal Patent Office on
the 26th September 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DONALD
MUNRO, of Johnstone, in the County of Renfrew, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of March, in the
year of our Lord One thousand eight hundred and seventy-one, in
the 35th year of Her reign, did, for Herself, Her heirs and successors
give and grant unto me, the said Donald Munro, Her special license
that I, the said Donald Munro, my executors, administrators, and
assigns, or such others as I, the said Donald Munro, my executors,
administrators, or 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 FURNACES AND BOILERS," upon the condition (amongst others) that I,
the said Donald Munro, by an instrument in writing under my hand

page_text: 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 Donald Munro, 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 :-
My said Invention, which relates to improvements in the construction
and arrangement of furnaces such as are used for puddling, boiling,
re-heating and forging iron, scrap furnaces, gas furnaces, and furnaces
used for other purposes, consists in forming the furnace doors and part
of the shell into cells through which water is passed for the purpose of
preventing the rapid wasting of the brickwork and metal of which the
doors and shell have hitherto been composed. The water is introduced
into the cells or spaces of the furnace door and flowing from a contiguous
cistern or tank this water is caused to pass from the door casing into
à boiler constituting the shell of the fire-grate. The circulation of
water through the door casing and shell of the fire-grate prevents their
rapid destruction and avoids the necessity of frequent renewal, thus
effecting considerable economy. The circulation of the water through
the boiler constituting the shell of the fire-grate has also the effect
of keeping it cool and preventing the "clinker" from adhering thereto
as is found to be the case under existing arrangements. The front
of the boiler constituting the shell of the fire-grate is provided with
a sliding door for the purpose of admitting air to the fire-grate when
its supply from the channels or chambers of the furnace is cut off.
The same sliding door being also opened whenever it becomes necessary
to draw the fire-bars.
66
"
And in order that my said Invention may be properly understood
I now proceed more particularly to set forth the system, mode, or
manner in or under which the same is or may be used or practically
carried into effect, that is to say :-
-
Upon the Sheet of Drawings hereunto appended Figure 1 is a side
elevation, Figure 2 a transverse vertical section upon the line A, B,

page_text: Figure 1, and Figure 3 a horizontal section upon the line C, D, Figure 1,
but with the door A and surrounding iron framework in plan at
their side marked A', shewing a reverberatory furnace constructed in
accordance with my Invention, whilst Figure 4 is an elevation of the
back or inner side of the door A, that side marked A¹ of Figure 5
being a plan of the same, the opposite side marked B a horizontal
section upon the line E, F, Figure 4, and Figure 6 a detached transverse
vertical section upon the line G, H, Figures 1 and 3, showing the
arrangement of the cell a in the door A, and also the form of the
frame or lintel C.
Under the arrangement of furnace shown the sliding door A of the
furnace is formed with a rectangular cell a passing along the bottom
and up each side, and terminating in an open trough a¹ extending the
full width at the top thereof. The cell a and trough a¹ are for holding
water, as herein-after set forth, whilst the recessed central part of the
door A, which is surrounded by the said cell a and trough a¹, is filled
with fire-brick, as shewn at Figures 3, 5, and 6. To both edges of the
door A and near the top thereof a bent pipe b is attached, the horizontal
part of which communicates with the trough a¹, whilst the vertical
portion thereof passes downwards into a vertical rectangular pipe B,
which constitutes the jamb of the doorway at either side. The lintel
of the said doorway consists of a rectangular box or trough C for holding
water, being open at the top and in communication with the jamb
pipes B by means of short pipes or passages c, as more particularly
shewn at the side marked A', Figure 3. The door A of the furnace
is opened or closed as desired by being moved vertically by means of
a counterbalance D, and band or chain d attached thereto and to the
top of the said door A, being passed over bearing pulleys e supported
by a framework E secured in the required position. Above the door A
a pipe fis situated with its lower end dipping into the trough a¹ of the
door A., near one edge thereof, so that when the said door A is drawn
upwards the pipe fenters the cell a situated at that side. The other
end of the pipe fis attached to and communicates with a tank F, which
may be placed in any suitable position above the level of the furnace.
Near the top of each of the jamb pipes B a pipe y is attached bent
downwards, as shewn, and attached at the lower end to a horizontal
pipe y', to which an injector is shown attached (or a pump may be
employed in lieu of an injector) the discharge pipe from which is

page_text: fixed to and in communication with a boiler G, which is arranged to
constitute the fire-box of the furnace, as shewn at Figures 1, 2, and 3.
Above the fire-grate II, at the part marked i, a break is by preference
formed in the inner shell of the boiler, as shewn at Figure 2, for the
purpose of admitting a lining I of fire-brick, as there shewn. The
boiler G is provided with a charging door, not shewn upon the Drawings,
whilst upon the front of the ash-pit Ka sliding door k, capable of being
moved upwards and downwards in a frame by means of a counter-
balance, is situated.
Having now described the arrangement and construction of the
various parts of a furnace arranged according to my Invention, the
manner wherein they constitute the means of preserving certain parts
of the furnace shell from rapid destruction by heat, as well as being the
means of heating feed water and generating steam in an improved and
economical manner will be understood as follows:- When the furnace
is in operation water is allowed to flow from the tank F through the
pipe f, and is discharged into the cells a, and trough a¹ of the door A,
and rising therein to the level of the pipes b flows through the said
pipes into the jamb pipes B, and rising in which it flows through the
pipes or passages c into the lintel C, being maintained at a uniform
level in the said jamb pipes B and lintel C, by means of the overflow
passing through the pipes g attached to the jambs B. As a regular
circulation of water is thus maintained through the door A, and also
through the jambs B and lintel C, it becomes heated, that portion of
it which has attained the highest temperature rising to the surface
is regularly discharged as the overflow through the pipes attached to
the jambs B, thence it passes into the horizontal pipe g¹, whence it
is injected into the boiler G by means of the injector h, so that the
waste heat from the fire is thereby absorbed and steam generated, thus
utilizing to a great degree the heat, which in other arrangements of
furnaces is lost. The sliding door k on the front of the ash-pit K is
provided for the purpose of admitting air to the fire-grate when its
supply from the air chamber W, shewn in dotted lines at Figure 1,
in which case the furnace acts from the draught of the chimney alone.
The door is also provided for being opened when it becomes necessary
to draw the fire-bars H.
Having now described the nature of my said Invention, and in what
manner the same is to be practically carried into effect, I desire to

page_text: observe in conclusion that the air flues or passages W constitute no
part thereof, as these correspond with similar air flues or passages
shown in the Drawings attached to the Specification of Thomas Ellis,
No. 1290, A.D. 1870. Further I desire it to be understood that my
Invention may be applied to or used with furnaces not having such
air flues or passages; what then I consider to be novel and original,
and therefore claim as the Invention secured to me by the hercin-before
in part recited Letters Patent is,—
First. The arrangement and construction of the furnace door and
doorway framing, with cells for containing water, as herein-before set
forth and shewn upon the accompanying Drawings, or any mere
modification thereof.
Second. The arrangement and construction of a boiler so as to con-
stitute the fire-box of a puddling, reheating, boiling, or scrap furnace,
as herein-before set forth and shewn upon the accompanying Sheet of
Drawings.
In witness whereof, I, the said Donald Munro, have hereunto
set my hand and seal, this Twenty-third day of September One
thousand eight hundred and seventy-one.