Ix- PROVEMENTS IN FURNACES
Year: 1870

page_text: LETTERS PATENT to John Donald, of Glasgow, in the County of
Lanark, North Britain, Iron Merchant, for the Invention of "Ix-
PROVEMENTS IN FURNACES."-A communication from abroad by Carl
Wittenstrom, residing at Motala, Sweden.
Sealed the 7th March 1871, and dated the 16th December 1870.
PROVISIONAL SPECIFICATION left by the said John Donald at the
Office of the Commissioners of Patents, with his Petition, on the
16th December 1870.
I, JOHN DONALD, of Glasgow, in the County of Lanark, North Britain,
Iron Merchant, do hereby declare the nature of the said Invention for
“IMPROVEMENTS IN FURNACES," to be as follows, that is to say :—
This Invention has for its object to obtain increased economy of fuel,
efficiency of action and convenient means of regulation in furnaces of
various kinds arranged for the production of heat by the combustion
of coal; and it consists of a peculiar construction of the fire-place or
chamber in which the coal is burned, and of parts in immediate con-

page_text: nection therewith, whilst the fire gases or heated gascous products of
combustion issuing from such chamber may be led into a reverberatory
or other chamber to act on metals or other substances therein, or they
may be led through the tubes or flues of a steam boiler, or through flues
in connection with a still, evaporating pan, or other object to be heated.
In carrying out the Invention the fire-place is made with its several
dimensions in about the proportions to cach other of the following
sizes: The horizontal section is of a rectangular form, measuring
18 inches broad by 14 inches long at the bottom, but the length
increases to 21%, inches at the upper part. The roof of the fire-place is
27 inches above the bottom grating, and the outlet for the fire gases
occupies at the inner side a depth of 8 inches below the roof.. The
bottom grating is made in one piece, with small openings for the passage
upwards of air, and it is fixed on a transverse shaft, and can by means
of an external lever be turned down into the ash-pit for cleaning out the i
fire-place. When the furnace is working the ash-pit is closed, and a
part of the air for combustion is led into it by a branch from a main
supplied by a fan or blowing engine, and the remainder of the air for
combustion is led by another branch pipe to the top of the fire-place
and into a casing formed with two concentric funnels. The air passes 2
between the two funnels and through the bottom one, and enters the
fire-place in a downward direction. The fuel is dropped into the upper
funnel and falls through it, and the lower one into the fire-place. The
fucl is broken into small pieces of about the size of walnuts, and is fed
in continuously by hand or otherwise at such a rate as to maintain a 2
depth of about six inches upon the bottom grating. The action of the
furnace is regulated by adjusting the supply of air, and by adjusting
the upper one of the two funnels so as to increase or diminish the space
between them through which the air passes.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of December, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Donald, Her special licence that I,
the said John Donald, my executors, administrators, and assigns, or such
others as I, the said John Donald, 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 FURNACES," a communication
to mo from abroad by Carl Wittenström, residing at Motala, Sweden,
upon the condition (amongst others) that I, the said John Donald, 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 John Donald, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, that is to say :-
The said Invention has for its object to obtain increased economy of
fuel, efficiency of action, and convenient means of regulation in furnaces
of various kinds arranged for the production of heat by the combustion
of coal, and it consists of a peculiar construction of the fire-place or
chamber in which the coal is burned, and of parts in immediate con-
nection therewith, whilst the fire gases or heated gaseous products of
combustion issuing from such chamber may be led into a reverberatory
or other chamber to act on metals or other substances therein; or they
may be led through the tubes or flues of a steam boiler, or through
flues in connection with a still, evaporating pan, or other object to be
heated.
19

page_text: of explanatory Drawings to be herein-after referred to, and showing by
way of example a few of the various modes of applying the improve-
ments. In these Drawings the same reference numerals are used to
mark the same or like parts wherever they are repeated.
Figure 1, on Sheet 1 of the Drawings, is a horizontal section, and
Figure 2 is a sectional clevation showing the mode of carrying out the
Invention in the case of an ordinary reverberatory or licating furnace.
In this example two fire-places 1 are constructed in connection with
and at opposite ends of a central reverberatory chamber 2. Each fire-
place 1 is made of the internal form and dimensions shown by one:
being represented in section, and the fire gases pass from each by a
passage 3 at the top of the inner side into the reverberatory chamber 2.
The bottom grating 4 is made in one piece with small openings for the
passage upwards of air, and it is fixed on a transverse shaft 5, and can
by means of an external lever 6 be turned down into the ash-pit 7 for 1
cleaning out the fire-place. When the furnace is working the ash-pit
door 8 is closed, and a part of the air for combustion is led into the
ash-pit by a branch pipe 9 from a main 10, supplied by a fan or blowing
engine, and the remainder of the air for combustion is led by another
branch pipe 11 to the top of the fire-place and into a casing 12 formed
with two concentric funnels 13, 14. The air passes between these two
funnels and through the bottom one 14 and enters the fire-place in a
downward direction. The coal or fuel is dropped into the upper
funnel 13, which is always open, and falls through it, and the lower
one 14, into the fire-place. The fuel is broken into small pieces of 2
about the size of walnuts, and is fed in continuously or at very
short intervals by hand or otherwise, at such a rate as to maintain
a depth of about six inches upon the bottom grating 4. The
action of the furnace is regulated by adjusting the supply of air by
means of a valve 15 on the main pipe 10, and by adjusting the upper ยู
one 13 of the two funnels, so as to increase or diminish the space
between them, through which the air enters the fire-place. For this
latter purpose the upper funnel 13 is made movable in the casing 12,
and is raised or lowered therein by means of screws. The air for com-
bustion being supplied as described there is always in the furnace a 3
pressure somewhat above that of the atmosphere, which is of well-known
advantage in many applications of reverberatory furnaces, whilst no
lofty chimney is required for inducing a draught. The improved furnace
is also free from smoke, and in the example shown in Figures 1 and 2,

page_text: no chimney is provided, the used products of combustion simply finding
their way to the outer atmosphere through the working doorway of the
reverberatory chamber and through openings in the opposite side.
Figures 3 and 4 show in horizontial and vertical section a double
5 furnace with four fire-places 1 and two reverberatory chambers 2, but
the middle partition 16 separating them may be removed if a large
single chamber is required. A short chimney 17 is shown in connection
with this furnace for the used gases to pass off by, the chambers 2
communicating with it by flues 18, indicated by dotted lines in
0 Figure 3.
Figure 5, on Sheet 2 of the Drawings, is a sectional elevation, showing
the application of the improved fire-place in connection with a Cornish
boiler. The fire-place 1 is simply constructed against the end of the
boiler 19 in such a way that the fire gases are discharged from it by
5 the passage 3 directly into the boiler flue indicated by dotted lines. If
the boiler has two internal flue tubes a separate fire-place may be applied
in connection with each.
Figure 6 is a vertical section showing an improved fire-place as
applied in connection with a marine boiler of ordinary type, and so as
O to deliver its fire gases into the space 20, which would ordinarily be
occupied by a common furnace.
4
In any of the applications the fire-place 1 may be internally of a
rectangular, circular, or intermediate form in horizontal section.
Figures 7 and 8 are vertical sections showing two modes of con-
5 structing or arranging the improved fire-place within boilers, and so as
to be surrounded by water spaces. In the modification shown in
Figure 7 the boiler is multitubular and the fire gases pass off from the
fire-place through a series of horizontal tubes. In the modification
shown in Figure 8 the fire gases pass off from the-fire-place by four
0 outlets 3 communicating with enclosed spaces or flues 21 outside of the
boiler, and descend through the latter to underground flues, indicated by
dotted lines, and leading them away. In this example the bottom grate 4
and an ash-box are arranged on wheels, so that they can be withdrawn
from under the boiler for cleaning.
5
'
Having thus particularly described the said Invention, and the manner
in which the same is to be performed, I have to state that I do not
restrict myself to the precise details herein described or delineated, but

page_text: that what I believe to be novel and original, and claim as the Invention
secured to me by the herein-before in part recited Letters Patent
is, the constructing of a furnace with a fire-place for burning coal of
about the proportions or form herein delineated or described, and
with provision for supplying air under pressure in two portions, one up 5
through the bottom grating and the other downwards from the top of
the fire-place through a funnel or equivalent opening, having within it
a funnel through which the fuel is introduced in small pieces, and
continuously or at very short intervals.
In witness whereof, I, the said John Donald, have hereunto set 1
my hand and scal, this Fourteenth day of June, in the year of
our Lord One thousand cight hundred and seventy-one.