IMPROVE- MENTS IN FURNACES FOR THE MANUFACTURE OF ALKALI
Year: 1866

page_text: LETTERS PATENT to James Cochran Stevenson, of South Shields, in the.
County of Durham, Alkali Manufacturer, for the Invention of "IMPROVE-
MENTS IN FURNACES FOR THE MANUFACTURE OF ALKALI."
Sealed the 18th April 1867, and dated the 24th October 1866.
PROVISIONAL SPECIFICATION left by the said James Cochran Stevenson
at the Office of the Commissioners of Patents, with his Petition, on the
24th October 1866.
I, JAMES COCHRAN STEVENSON, of South Shields, in the County of Durham,
Alkali Manufacturer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN FURNACES FOR THE MANUFACTURE OF ALKALI," to be as
follows:-
These improvements are applicable to the manufacture of black asb by the
revolving cylindrical furnace patented by Elliott and Russell on the 18th day
of April 1858 (No. 887), and consists in so arranging the furnace as to admit
of using the waste heat of the cylindrical furnace for the purpose of partially
calcining the chalk or limestone to be afterwards used in the cylinder. I
attach to the exit end of the cylinder a reverberatory furnace through which
the waste heat from the cylinder is made to pass; this furnace is provided
with a working door on each side, and the chalk or limestone is charged into
it through an opening in the arch and turned over by the workman on
the hearth or bed of the furnace, and when ready to be transferred into the
cylinder is cast into it with a paddle through the exit opening of the cylinder.

page_text: or the heated materials may be drawn out of the reverberatory furnace and
elevated to the top of the cylinder and charged into it in the usual manner.
The chalk (or limestone) is crushed before being charged into the reverberatory
furnace, and may be mixed with coal to facilitate the calcination. The
reverberatory furnace may also be used for the preliminary heating of the
other ingredients of the black ash, namely, the sulphate of soda and coal, or
for the preliminary heating of the chalk (or limestone) sulphate of soda and
coal mixed together. These furnaces are also applicable to the making of
black ash from sulphate of potash. Beyond the reverberatory furnace is a
surface heat evaporating pan, over which the gases from the reverberatory
furnace play, and in this way the waste heat is further utilized.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Cochran Stevenson in the Great Seal Patent Office
on the 23rd April 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
COCHRAN STEVENSON, of South Shields, in the County of Durham, Alkali
Manufacturer, send greeting.
· WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of October, in the year of our Lord
One thousand eight hundred and sixty-six; in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said James Cochran Stevenson, Her special licence that I, the said James
Cochran Stevenson, my executors, administrators, and assigns, or such others
as I, the said James Cochran Stevenson, 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 FOR THE MANUFACTURE OF ALKALI," upon the con-
dition (amongst others) that I, the said James Cochran Stevenson, 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 per-
formed, 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.

page_text: NOW KNOW YE, that I, the said James Cochran Stevenson, 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 thereof, that is to say :-
These improvements are applicable to the manufacture of black ash by the
revolving cylindrical furnace patented by Elliott and Russell on the 18th day of
April 1853 (No. 887), and consist in so arranging the furnace as to admit
of using the waste heat of the cylindrical furnace for the purpose of partially
calcining the chalk or limestone to be afterwards used in the cylinder. I
attach to the exit end of the cylinder a reverberatory furnace through which
the waste heat from the cylinder is made to pass; this furnace is provided with
a working door on each side, and the chalk or limestone is charged into it
through an opening in the arch, and turned over by the workman on the
hearth or bed of the furnace, and when ready to be transferred into the cylinder
is cast into it with a paddle through the exit opening of the cylinder, or the
heated materials may be drawn out of the reverberatory furnace and elevated
to the top of the cylinder and charged into it in the usual manner. Beyond the
feverberatory furnace is a surface heat-evaporating pan, over which the gases
from the reverberatory furnace play, and in this way the waste heat is further
utilized.
According to the arrangement which I prefer the reverberatory furnace
attached to the exit end of the cylinder is constructed in the following
manner: The end wall next the cylinder is 9 inches thick, and is provided
with a circular opening of the same diameter as the exit opening of the
cylinder, which diameter for a cylinder working a charge of 21 hundred-
weights of sulphate of soda is 2 feet 4 inches. The level of the hearth or bed
of the furnace is one foot below the bottom of the circular opening; the
internal dimensions of the bed are 8 feet from end to end and 10 feet widė.
The roof of the furnace is arched, the crown being 3. feet 6 inches high above
the bed at the end. next the cylinder, and 2 feet 6 inches at the other end.
In the arch and over the centre of the bed is an opening 1 foot 6 inches square
fitted with a door or cover through which the chalk or limestone is dropped
from above; the side walls supporting the arch are 1 foot 3 inches thick,
and are each provided with a working door placed opposite the centre of the
bed. A bridge at the further end of the bed from the cylinder, and one foot
higb, separates the bed from the surface evaporating pan, over which the flame
passes after it has left the bed of the reverberatory furnace; when dried chalk
or limestone is used it is to be crushed so as to pass through a screen of which
the spaces are 1 inches wide, but damp-chalk-may-be used without being
:

page_text: crushed. For a charge of 21 cwts. of sulphate of soda 21 cwts. of dried chalk
and 12 cwts. of small coal are employed. One half of the chalk is charged
into the reverberatory furnace at the commencement of the working of the
preceding charge of black ash, and is turned over by the. workman and
partially calcined by the waste heat issuing from the cylinder during a period
of about 2 hours, which is the time required for the working of each charge of
black ash. When the preceding charge is drawn from the cylinder the other
half of the chalk mixed with 6 cwts. of coal is dropped into the cylinder and
the cylinder set in motion; the workmen then cast the first half of the charge
of chalk into the cylinder with paddles through the circular opening, which
completes the introduction of the full charge of chalk; immediately thereafter
the first half of the succeeding charge of chalk is dropped into the rever-
beratory furnace. The calcination of the chalk within the cylinder is continued
for about 45 minutes longer, when the cylinder is stopped and the sulphate of
soda with the remaining 6 cwts. of coal is introduced, and in about an hour
longer the operation is complete and the charge of black ash withdrawn; a
charge of black ash is completed every 2 hours. The reverberatory furnace
may also be used for the preliminary heating of the other ingredients of the
black asb, namely, the sulphate of soda and coal, or for the preliminary
heating of the chalk (or limestone) sulphate of soda and coal mixed together.
These furnaces are also applicable to the making of black ash from sulphate of
potash.
What I claim is the constructing furnaces for the manufacture of alkali in
such manner that the waste heat of the cylindrical furnace is caused to pass
into a reverberatory furnace or chamber in which the chalk or limestone to
be afterwards used in the cylinder may be partially calcined, or in which
the preliminary heating of the other ingredients of the black ash may be.
effected.
In witness whereof, I, the said James Cochran Stevenson, have hereunto
set my hand and seal, this Twentieth day of April, in the year of our
Lord One thousand eight hundred and sixty-seven.
JAMES COCHRAN STEVENSON. (L.s.)