IMPROVEMENTS IN THE PRODUCTION OF CHLORINE AND HYDROCHLORIC ACID, AND IN APPARATUS EMPLOYED THEREIN.
Year: 1872

page_text: LETTERS PATENT to James Hargreaves, of Widnes, in the County
of Lancaster, Chemist, and Thomas Robinson, of the same Place,
Ironfounder, for the Invention of "IMPROVEMENTS IN THE PRODUCTION
OF CHLORINE AND HYDROCHLORIC ACID, AND IN APPARATUS EMPLOYED
THEREIN.
"
Sealed the 13th August 1872, and dated the 17th February 1872.
PROVISIONAL SPECIFICATION left by the said James Hargreaves
and Thomas Robinson at the Office of the Commissioners of Patents,
with their Petition, on the 17th February 1872.
We, JAMES HARGREAVES, of Widnes, in the County of Lancaster,
Chemist, and THOMAS ROBINSON, of the same Place, Ironfounder, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE PRODUCTION OF CHLORINE AND. HYDROCHLORIC ACID, AND IN APPARATUS
EMPLOYED THEREIN,” to be as follows:-
:-
"

page_text: nesium or manganese, either in the form of oxide or as a salt, may be
also added to assist in rendering the conversion of oxide of chromium
into chromic acid more rapid. The said mixture of chloride of sodium or
chloride of potassium with oxide of chromium and with or without
magnesium or manganese, as aforesaid, and which we hereinafter for the
sake of brevity call "the mixture," is then made into bricks or other
suitably shaped pieces of regular or irregular forms by mixing in a moist
state, moulding, and drying. The said bricks or pieces of the mixture
are then placed in a furnace or chamber heated on the outside so as not
to allow evolved chlorine to mix with the products of combustion which
are produced from the fuel used in heating the said furnace or chamber.
Oxygen or atmospheric air is caused to flow or filter through the inter-
stices or spaces between the said bricks or pieces, so as to pass through
or amongst the pieces of the mixture. The sodium or potassium is or
are converted thereby into chromate, and chlorine evolved.
When we wish to produce hydrochloric acid we add water or the
vapour thereof to the air or oxygen used to oxidize the mixture. In
practice a series of two or more furnaces or chambers may be used, and
air caused to pass through the interstices between the pieces of the
mixture contained in the series, entering at the furnace or chamber
containing the bricks or pieces of the mixture which is most nearly
converted into chromate, and going out at the furnace or chamber which
has most recently been filled. We so arrange the passages and dampers
connected in and with the said series of furnaces or chambers that each
furnace or chamber becomes in its turn the first, intermediate, and last
of the series. The said furnaces or chambers may be made of fire-brick
or other suitable heat resisting materials, care being taken to make all
joints as tight as possible so as to avoid leakage; or they may be made
of iron or other metal lined with bricks or fire resisting material. The
oxygen or atmospheric air used in oxidizing the said mixture may be
superheated to such a degree as shall not injuriously cool the mixture at
the point of entrance. The temperature of the said mixture is main-
tained at red heat; this may be exceeded, but it is not advisable to raise
the temperature so high as to flux or fuse the said mixture. The propor-
tions of oxide of chromium to the chloride of sodium or chloride of
potassium may be considerably varied so as to produce various desired
results; it is preferable however that the oxide of chromium should be
in considerable excess where it is desirable to decompose the whole or

page_text: nearly the whole of the chloride used. We find one part of chloride of
sodium or chloride of potassium with from two to three parts of oxide of
chromium to work very well.
Another method by which we may carry our said Invention into effect
is by employing the atmospheric air or oxygen which is used in oxodizing
the mixture to heat such mixture, without external firing. The atmo-
spheric air or oxygen is heated to a red heat, the well-known air heating
apparatus of the Messrs. Siemens, or other apparatus which will raise the
temperature of the said oxygen or atmospheric air sufficiently high, and
then passed amongst the mixture.
In carrying this modification of our said Invention into effect, we
employ a chamber or series of connected chambers covered and sur-
5 SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Hargreaves and Thomas Robinson in
the Great Seal Patent Office on the 16th August 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
HARGREAVES, of Widnes, in the County of Lancaster, Chemist, and
THOMAS ROBINSON, of the same Place, Ironfounder, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of February, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said James Hargreaves and Thomas
Robinson, Her special licence that we, the said James Hargreaves
and Thomas Robinson, our executors, administrators, and assigns, or
such others as we, the said James Hargreaves and Thomas Robinson,
our 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,

page_text: 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 THE PRODUCTION OF CHLORINE AND HYDROCHLORIC ACID, AND
IN APPARATUS EMPLOYED THEREIN," upon the condition (amongst others) that
we, the said James Hargreaves and Thomas Robinson, our executors
or administrators, by an instrument in writing under our, 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

page_text: the air caused to pass through the interstices between the pieces of the
mixture contained in the series entering at the furnace or chamber
containing the bricks or pieces of the mixture which is most nearly
converted into chromate, and going out at the furnace or chamber which
has most recently been filled. We so arrange the passages and dampers
connected in and with the said series of furnaces or chambers that each
furnace or chamber becomes in its turn the first, intermediate, and last
of the series. The said furnaces or chambers may be made of fire-brick
or other suitable heat resisting materials, care being taken to make all
joints as tight as possible, so as to avoid leakage; or they may be made
of iron or other metal lined with bricks or fire resisting material. The
oxygen or atmospheric air used in oxidizing the said mixture may
be superheated to such a degree as shall not injuriously cool the mixture
at the point of entrance. The temperature of the said mixture is main-
tained at red heat; this may be exceeded, but it is not advisable to raise
the temperature so high as to flux or fuse the said mixture. The
proportions of oxide of chromium to chloride of sodium or chloride of
potassium may be considerably varied so as to produce various desired
results, it is preferable however that the oxide of chromium should be in
considerable excess where it is desirable to decompose the whole or
nearly the whole of the chloride used. We find one part of chloride of
sodium or chloride of potassium with from two to three parts of oxide
of chromium to work very well.
Another method by which we carry our said Invention into effect is
by employing the atmospheric air or oxygen, which is used in oxidizing
the mixture, to heat such mixture without external firing. The atmo-
spheric air or oxygen is heated to a red heat in the well-known air
heating apparatus of the Messrs. Siemens, or in other apparatus which
will raise the temperature of the said oxygen or atmospheric air
sufficiently high, and then passed amongst the mixture.
In carrying this modification of our said Invention into effect, we
employ a chamber or series of connected chambers covered and sur-
rounded by materials which are slow conductors of heat, such for instance
as magnesia bricks.
Having now described the nature of our said Invention and par-
ticularized the same, we claim the employment in the production of

page_text: chlorine and hydrochloric acid of the means and apparatus herein
described.
In witness whereof, I, the said James Hargreaves, have hereunto
set my hand and seal, this Third day of August, in the year
of our Lord One thousand eight hundred and seventy-two.
E
JAMES HARGREAVES.
(L.S.)
In the presence of
JAMES JOHNSON.