AN IMPROVED PROCESS OF AND APPARATUS FOR MANU- FACTURING CAUSTIC SODA."
Year: 1873

page_text: LETTERS PATENT to Louis Bois, fils, of Lyon, Chemist, for the
Invention of "AN IMPROVED PROCESS OF AND APPARATUS FOR MANU-
FACTURING CAUSTIC SODA."
PROVISIONAL SPECIFICATION left by the said Louis Bois at the
Office of the Commissioners of Patents, with his Petition, on the
23rd October 1873.
I, LOUIS BOIS, fils, of Lyon, Chemist, do hereby declare the nature
of the said Invention for "AN IMPROVED PROCESS OF AND APPARATUS FOR
MANUFACTURING CAUSTIC SODA," to be as follows:-
This relates to a new process and special apparatus for the economic
manufacture of caustic soda.
My Invention consists in causing steam to circulate through cast-iron
pipes heated to a red heat, and containing scrap or waste iron for com-
mencing the decomposition of water, the oxygen of which is carried in
part upon the iron. The vapour is then immediately directed into a

page_text: series of pipes of refractory material also heated to a red heat, and con-
taining salts of soda or carbonate of soda. In this latter course the salts
of soda take up the oxygen of the steam, and are transformed into
caustic soda whilst the hydrogen is driven out.
My apparatus for the realization of this process is represented in the 5
annexed Drawings.
Figure 1 is a transverse section, and Figure 2 is a longitudinal
horizontal section.
This apparatus is composed of a series of cast-iron pipes a, a, disposed
parallel in the same horizontal plane, and united at alternate ends by 1
bends to constitute a continuous zig-zag. These pipes are filled with
waste iron, and the steam is conveyed to them by a tube 9 coming
from a generator, the other end of the zig-zag scrics communicating by
a tube c with the second set of pipes, which are arranged vertically.
The vertical pipes are of larger diameter d, d, and of refractory clay,
and they contain salts of soda or carbonate of soda. The outlet end of
this vertical series of pipes is provided with a tube f, which passes out
into a receiver arranged for this purpose.
The horizontal series of pipes and the vertical one are disposed in the
same chamber, but apart from each other, and the heat from a furnace
arranged under the horizontal pipes is led therefrom to heat the perpen-
dicular ones before passing into the flue.
The waste iron in the pipes a and the salts of soda in the pipes d, d,
are heated to a red heat, as above stated.
On coming into contact with the red-hot waste iron the steam sud-
denly commences to become decomposed, and a part of its oxygen is
carried to the iron. This vapour is immediately siezed by the salts of
soda, which absorbs all the oxygen, in order to transform itself into
caustic soda, while the hydrogen rendered free is received by a tube f
outside.
The draft holes m, m, are arranged at convenient parts of the fur-
nace A for giving every facility for cleaning, charging, and emptying
the two series of pipes, the vertical pipes having moveable flanges or
caps.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Louis Bois, in the Great Seal Patent Office on
the 7th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
Bois, fils, of Lyons, Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of October, in the
year of our Lord One thousand eight hundred and seventy-three, in
the thirty-seventh year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Louis Bois, fils, Her
special licence that I, the said Louis Bois, fils, my executors,
administrators, and assigns, or such others as I, the said Louis
Bois, fils, 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 "AN IMPROVED PROCESS OF MANUFACTURING CAUSTIC SODA,"
upon the condition (amongst others) that I, the said Louis Bois, fils,
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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Louis Bois, fils, 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 thereof, reference being had to the Drawings here-
unto annexed, that is to say:-
This relates to a new process and special apparatus for the economic
manufacture of caustic soda.
7
My Invention consists in causing steam to circulate through cast-iron
pipes heated to a red heat, and containing scrap or waste iron for com-
5 mencing the decomposition of the water, the oxygen of which partly

page_text: combines with the iron. The steam is then immediately directed into a
scries of tubes of pipc-clay or other refractory material heated to a
deep red heat, and containing salts of soda or carbonate of soda. In the
passage of the steam through these pipes the salts of soda take up its
oxygen, and become transformed into caustic soda whilst the hydrogen
is set free.
The apparatus I have invented for carrying out this process is repre-
sented in the annexed Drawings, in which Figure 1 is a transverse
section, and Figure 2 a longitudinal horizontal section.
This apparatus is composed of a series of cast-iron pipes a, a, arranged
parallelly in the same horizontal plane, and united one to another at
their alternate ends by bends or curved joints, so as to constitute
a continuous zig-zag or serpentine. These pipes are filled with
small pieces of scrap or waste iron, and the steam is conveyed to them
by a tube coming from a boiler or generator, the other end of the
zig-zag series communicating by a tube c with the second set of tubes,
which are arranged vertically.
. These vertical tubes d, d, are of larger diameter, and are formed of
pipe-clay or refractory material, and contain salts of soda or carbonate of
soda. The outlet end of this vertical series of tubes is provided with an 2
escape pipe f, which passes out into a receiver arranged for this purposc.
The horizontal series of pipes and the vertical series are arranged in
the same furnace A, consisting of two flues B, C, perpendicular one to
the other, and which receive heat from a common grate F.
The scrap or waste iron in the pipes a and the salts or carbonate of 2
soda in the pipe d, d, are heated to a red heat, as above stated.
On coming into contact with the red-hot waste iron the steam under-
goes a partial decomposition, and a part of its oxygen immediately unites
with the iron. The partially decomposed steam is then immediately
seized by the salts of soda, which absorbs all the remaining oxygen in
order to become transformed into caustic soda, while the hydrogen set
free is received by a tubo fleading outside the apparatus.
Peep holes m, m, are arranged at convenient parts of the furnace A
for giving every facility for cleaning, charging, and emptying the two
series of pipes, and the vertical tubes are arranged for this purpose with 3
moveable flanges or caps.

page_text: what manner the same is to be performed, I declare that I claim,--
Firstly. The manufacture of caustic soda by the process herein-before
described.
Secondly. The apparatus as herein-before described, and as shown
in the accompanying Drawings, for the manufacture of caustic soda,
or any mere modification thereof.
In witness whereof, I, the said Louis Bois, fils, have hereunto set
my hand and scal, this Twenty-fourth day of December, One
thousand eight hundred and seventy-three.
Witness,
ALBERT CAHEN,
Civil Engineer,
of Boulevard Magenta, 32,
at Paris.
L. BOIS, FILS. (L.S.)