IMPROVEMENTS CONNECTED WITH FURNACES USED IN THE MANUFACTURE OF COAL GAS
Year: 1872

page_text: Sealed the 28th February, 1873, and dated the 28th October 1872.
PROVISIONAL SPECIFICATION left by the said John Rowcroft Mac-
farlane, at the Office of the Commissioners of Patents, with his
Petition, on the 28th October 1872.
I, JOHN ROWCROFT MACFARLANE, of the City of Manchester, in the
County of Lancaster, Gas Engineer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS CONNECTED WITH FURNACES USED IN THE
MANUFACTURE OF COAL GAS," to be as follows:-
The object of this Invention is to effect great economy in the con-
sumption of the fuel used for heating the retorts by enabling intensely
heated air to be supplied or drawn to the furnaces.

page_text: Instead of allowing the cold air to pass into the open ash-pit and
between the grate bars of each furnace as at present, I close the front of
the ash-pit and cause the air to pass through a horizontal flue on the
top or in the interior of the horizontal chimney flue through one or
more vertical flues in the retort oven, and through one or more horizontal
flues connected with the ash-pit.
The heated gases from the ignited fuel in their passage from the
retort oven to the chimney flue and chimney cause the chimney flue to
be of a great heat, and much of this heat is given off to the horizontal
air flue, and the vertical flue or flues in the oven are as hot as the
retorts, and therefore after the air passes first through the horizontal
air flue, and then through the vertical flue or flues, it becomes intensely
heated, and the combustion of the fuel is effected without any check of
cold air.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Rowcroft Macfarlane in the Great. Seal
Patent Office on the 28th April 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
RowCROFT MACFARLANE, of the City of Manchester, in the County of.
Lancaster, Gas Engineer, send greeting.
'
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of October, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant me, the said John Rowcroft Macfarlane, Her special
license that I, the said John Rowcroft Macfarlane, my executors,
administrators, and assigns, or such others as I, the said John Rowcroft,
Macfarlane, 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 CONNECTED WITH FURNACES USED IN THE MANUFACTURE OF COAL

page_text: GAS," upon the condition (amongst others) that I, the said John
Rowcroft Macfarlane, 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 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 John Rowcroft Macfarlane, 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 (that is to say):-
The object of this Invention is to effect great economy in the con-
sumption of the fuel used for heating the retorts by enabling intensely
heated air to be supplied or drawn to the furnaces.
Instead of allowing the cold air to pass into the open ash-pit and
between the grate bars of each furnace as at present, I close the front of
the ash-pit and cause the air to pass through one or more horizontal.
flues on the top or in the interior of the horizontal chimney flue, and
through one or more vertical flues in the retort oven, and through one
or more horizontal flues leading to the ash-pit below the grate bars.
The heated gases from the ignited fuel in their passage from the
retort oven to the chimney flue and chimney cause the chimney flue to
be of great heat, and much of this heat is given off to the horizontal air
flue or flues, and the vertical flue or flues in the oven are as hot as the
retorts; and therefore after the air passes first through the horizontal air
flue or flues, and then through the vertical flue or flues, it becomes
intensely heated without any check of cold air.
These improvements will be clearly understood by referring to the
figures and letters on the accompanying two Sheet of Drawings, in
which Figs. 1 and 2 are sectional plans, and Figs. 3 and 4 are transverse
and longitudinal sections of a retort oven provided with one arrangement
of my improvements; and Fig. 5 is a sectional plan, and Figs. 6 and 7
transverse and longitudinal sections of a modification of the same, Fig. 1
being a section at the line P, R, Fig. 3; Fig. 2, a sectional plan at the
line C, D, Fig. 4, of part of the horizontal hot air flue in the chimney

page_text: flue and the horizontal flues below the fire-bars; Fig. 3, a section at the
line L, M; Fig. 4, which is a section of Fig. 3 at the lines A, B, C,
Fig. 2. In the modification shewn in Figs. 5, 6, and 7, Fig 5 is a plan
having the cover of the hot chimney flue removed; Fig. 6, a section at
I, K, Fig. 5; and Fig. 7 a section of Fig. 5 at O, T.
In one or other of the Figs. 1, 2, 3, and 4, a represents the ordinary
retort oven; b, the retorts; c, retort supports; d, the grate bars; e; the
ash-pit; the chimney flues leading to the common chimney; g, the
flue leading from the retort oven to the chimney flue; h, a plate or
cover to prevent the admission of cold air to the ash-pit. In both the
chimney flues which are separated by the wall / between the two retort
ovens I place horizontal flues 1, each opening at one end to the atmo-
sphere by the pipe or passage m, and at the other end to the top of the
vertical flue n, the bottom of which communicates with horizontal
flues o, p, q, with the ash-pit e, from whence it passes upwards between
the grate bars to the furnace, and from thence through the ordinary.
flues to the chimney, and in the horizontal flue 1, Figs. 2 and 3, there
are hollow domes which cause the air to circulate in zig-zag directions ;
but in Figs. 5, 6, and 7, Sheet 2, the air passes through the passage t,
through tubes u to the horizontal flue v, and from thence down the
vertical flue w to the horizontal flues leading below a closed ask-
pit, from whence it passes between the grate bars to the furnace as
before.
It is well known that the chimney flue becomes exceedingly hot, and
the vertical flues being in the retort ovens must be intensely.heated, and
therefore the air which passes through the various flues and tubes to the
ash-pit will be as hot or nearly so as the flues themselves, and thus the
furnace will be supplied with intensely heated air, and effect an economy
of fuel to a great extent.
These Figures represent the main feature of my Invention, but it is
evident the details can be modified to suit the varied dimensions and
arrangements of different settings of retorts, and also instead of the
hollow domes, Figs. 1 and 2, they may be of various shapes, and placed
in various positions or entirely dispensed with; and also instead of using
three tubes, as shewn in Figs. 5, 6, and 7, there may be more or less as
desired.

page_text: Having now described the nature and particulars of my said Invention,
and the manner in which the same is to be made and worked, I desire it
to be understood that I claim the system and arrangements of apparatus
for causing intensely heated air to be supplied to the furnaces used in
the manufacture of coal gas, as herein described and illustrated on
the accompanying two Sheets of Drawings, or any mere modification
thereof.
In witness whereof, I, the said John Rowcroft Macfarlane, have
hereunto set my hand and seal, this Twenty-fourth day of April,
in the year of our Lord One thousand eight hundred and seventy-
three.
JOHN R. MACFARLANE. (L.S.)
Signed, sealed, and delivered by the
before-named John Rowcroft Mac-
farlane, in the presence of
G. SEPTIMUS HUGHES,
Patent Agent,
Manchester.