Improvements in or relating to the Manufacture of Bleaching Powder and other Hypochlorites.
Year: 1894

page_text: Date of Application, 4th Aug., 1894
Complete Specification Left, 3rd May, 1895-Accepted, 8th June, 1895
Improvements in or relating to the Manufacture of Bleaching
Powder and other Hypochlorites.
A communication from E. SOLVAY, of 25, Rue du Prince Albert, Brussels,
Belgium.
I, WILLIAM LLOYD WISE, of No. 46 Lincoln's Inn Fields in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention to be as follows:-
In the electrolysis of chloride of sodium for the manufacture of caustic soda
and chlorine, there is also produced hydrogen which can be obtained separately
from the chlorine without difficulty when the electrolytic cells are provided with
diaphragins arranged between the electrodes.
There are however many forms of electrolytic apparatus which are very efficient
as regards the electrolytic process proper, but in which the evolved hydrogen and
chlorine become mixed together. This result has, up to the present time, been
regarded as a very serious drawback where the chlorine is to be used in the
manufacture of chloride of lime, on account of the known fact that a mixture
of this kind is not only explosive in contact with a flame, or with a spark, but
even by mere exposure to sunlight. Now as chloride of lime chambers are
usually of very large size, the volume of explosive gaseous mixture they would
contain would be too large to permit of the safe use of such a mixture in ordinary
practice.
Now having ascertained that the presence of hydrogen is not prejudicial to
the absorption of chlorine by lime and that hydrogen, bas no reducing action in
the manufacture of chloride of lime, I have sought to provide a means of
enabling chloride of lime to be manufactured in a practical manner and without
danger, with the normal mixture of chlorine and hydrogen produced by the
electrolysis of chlorides, for which purpose I employ according to one mode of
carrying out my invention, a chlorinator of small capacity, that is to say, a con-
tinuous-action chlorinator. There are several known types of chlorinators of
small capacity in which lime and chlorine are brought into contact with each
other in a systematic manner. It is preferred however to employ a revolving
horizontal cylinder arranged with its axis at a slight inclination to the horizontal
and provided internally with helical ribs.
Another means of preventing all risk of explosion of the gaseous mixture
consists in collecting at the outlet of the chlorinating chambers the unabsorbed
gas, which consists practically of pure hydrogen, and mingling it again with the
entering gaseous mixture until the proportion of hydrogen in the mixture is such
that the latter ceases to be spontaneously explosive. The hydrogen thus added
in excess, acts as an inert or neutral gas and the mixture is thereby rendered
non-explosive. In this case, the use of a continuous-action chlorinator is
unnecessary and the ordinary chlorinating chambers may be employed.
As the manufacture of the other hypochlorites is effected by a liquid process
without the use of a body of gas, I am able to employ the mixture of chlorine and
hydrogen direct without inconvenience.
Dated this 4th day of August 1894.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.

page_text: Improvements in or relating to the Manufacture of Bleaching
Powder and other Hypochlorites.
A communication from E. SOLVAY, of 25, Rue du Prince Albert, Brussels,
Belgium.
I, WILLIAM LLOYD WISE, of No. 46 Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
In the electrolysis of chloride of sodium for the manufacture of caustic soda and
chlorine, there is also produced hydrogen which can be obtained separately from
the chlorine without difficulty when the electrolytic cells are provided with
diaphragms arranged between the electrodes.
There are however many forms of electrolytic apparatus which are very efficient
as regards the electrolytic process proper, but in which the evolved hydrogen and
chlorine become mixed together. This result has, up to the present time, been
regarded as a very serious drawback where the chlorine is to be used in the
manufacture of chloride of lime, on account of the known fact that a gaseous
mixture of this kind is not only explosive in contact with a Hame, or with a spark,
but even by mere exposure to sunlight. Now as chloride of lime chambers are
usually of very large size, the volume of explosive gaseous mixture they would
contain would be too large to permit of the safe use of such a mixture in ordinary
practice.
Now having ascertained that the presence of hydrogen is not prejudicial to the
absorption of chlorine by lime, and that hydrogen has no reducing action in the
manufacture of chloride of lime, I have sought to provide a means of enabling
chloride of lime to be manufactured in a practical manner and without danger,
with the normal mixture of chlorine and hydrogen produced by the electrolysis of
chlorides. For this purpose I employ, according to one mode of carrying out my
invention, a chlorinator of small capacity, that is to say, a continuous-action
chlorinator. There are several known types of chlorinators of small capacity in
which lime and chlorine are brought into contact with each other in a systematic
manner. It is preferred however to employ a revolving cylinder arranged with
its axis at a slight inclination to the horizontal, and provided internally with
helical ribs.
Another means of preventing all risk of explosion of the gaseous mixture,
consists in collecting at the outlet of the chlorinating chambers, the unabsorbed
gas, which consists practically of pure hydrogen, and mingling it again with the
entering gaseous mixture until the proportion of hydrogen in the mixture is such
that the latter ceases to be spontaneously explosive. The hydrogen thus added in
excess, acts as an inert or neutral gas and the mixture is thereby rendered non-
explosive. In this case the use of a continuous-action chlorinator is unnecessary
and the ordinary chlorinating chambers may be employed.
As the manufacture of the other hypochlorites is effected by a liquid process
without the use of a body of gas, I am able to employ the mixture of chlorine and
hydrogen direct without inconvenience.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
clain: is:-
1. In the manufacture of bleaching powder and other hypochlorites, the use

page_text: of a gaseous mixture of chlorine and hydrogen such as is produced by the
electrolysis of chlorides, substantially as described.
2. In the manufacture of bleaching powder, the use of a gaseous mixture of
chlorine and hydrogen obtained by electrolysis, the said mixture being used in a
continuous-action chlorinator, substantially as described.
3. In the manufacture of bleaching powder by means of a gaseous mixture of
chlorine and hydrogen obtained by electrolysis, the addition to the said mixture
of chlorine and hydrogen before use, of a quantity of hydrogen (obtained from
a previous operation) sufficient in quantity to render the gaseous mixture no
longer explosive, substantially as described.
Dated this 3rd day of May 1895.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.