IMPROVEMENTS IN THE MANUFACTURE OF CHLORIDE OF LIME OR BLEACHING POWDER, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office of
the Commissioners of Patents on the 20th September 1877. A communication
from abroad by Emile Malétra, of Paris, in the Republic of France.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THE MANUFACTURE OF CHLORIDE OF LIME OR
BLEACHING POWDER, AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREIN.”
[A communication from abroad by Emile Malétra, of Paris, in the Republic of
France.]
This Invention relates to a new process for the manufacture in an expeditious
manner of dry chloride of lime or bleaching powder, and consists in the employ-
ment of mechanical means for stirring, agitating, or mixing the powdered lime and
the chloride of lime, as fast as it is formed, in such a manner as to expose all the
molecules of these substances in succession to the continuous action of the gaseous
chlorine which is introduced under favorable conditions for combining with the
lime, and is rapidly absorbed by the latter. The mechanical means for obtaining
its continuous stirring or mixing action may be varied, but it is preferred to employ
a cylinder fitted with a shaft carrying rotating arms and pallets, as herein-after
described, or a revolving cylinder and a stationary shaft with pallets may be used
in substitution for the converse arrangement before mentioned.
The forms, dimensions, proportions, and materials employed in the construction
of the apparatns may be varied as well as the accessory parts, but the arrangement
herein-after described has been found convenient in practise.
The lime and chlorine are introduced into a cylinder of sheet metal or other
suitable material, by preference arranged horizontally, such cylinder being closed at
both ends, and provided with a door at each extremity, and also with one in the
centre at the lower part, through which latter the product may be discharged into
a truck placed beneath.
Apertures are formed in the upper part of the cylinder for the introduction of
the lime which it is desired to convert into chloride, about which apertures sieves
are provided. Through the cylinder passes a shaft fitted with arms carrying
pallets of sheet metal at their extremities; the arms are arranged upon the shaft

page_text: with a space between them in such a manner as to form a species of spiral acting
continuously upon the substances contained in the cylinder. Motion is imparted to
the shaft by a mechanical arrangement of toothed wheels or bands so as to cause
it to perform, say, from 12 to 20 revolutions per minute.
The pallets take up the line in turn and carry it to the upper part of the cylinder;
an intimate and complete mixture is thus effected by the continued changing of the
surfaces consequent on the rotatory motion. Any other mode of stirring or mixing
calculated to effect the same object may be employed in substitution for that herein-
before described.
The chlorine is introduced at the upper part of the cylinder through 4 pipes, for
example, which are placed in communication with the gas generators, and it is
wholly absorbed as fast as it comes in contact with the lime.
A thermometer provided at the upper part of the cylinder into which it dips
indicates the internal temperature and serves as a guide in conducting the opera-
tion; the absorption of chlorine by the lime producing an elevation of temperature;
the thermometer indicates whether the gas is entering too rapidly or otherwise.
A valve on the main pipe conducting the chlorine enables the supply to be
regulated, and glass tubes secured by india-rubber are provided for the facility of
exercising a supervision over the operation, the presence of the chlorine being dis-
covered by its green colour.
At the upper part of the cylinder there are provided two openings capable of
being closed, when required, by sheet-metal covers, such openings forming an exit
for the heat and moisture. The absorption of the gas is so rapid and complete that
it is seldom necessary to close these apertures.
In summer time, if the temperature of the external atmosphere is so high as to
prevent the cylinder from cooling sufficiently, this inconvenience may be obviated
by employing a stream of water flowing continuously in a double case or any other
analogous means.
In order to ensure regularity in the manufacture it is necessary to couple at least
two apparatus together so as to admit of the chlorine being directed into either
as required.
The process is very rapid and is carried out with great facility and without any
waste of chlorine. The progress of the operation may be constantly watched by
persons near the apparatus, which emits no injurious odours. The apparatus is
cheap in construction and occupies but small space.
The manufacture may be regulated at will as examples of absolute homo-
geneity (as may be ascertained by testing) nay be taken at any time during the
operation.
As the chloride of lime manufactured in this manner is homogeneous in every part,
it is not liable to become decomposed, as is the case with chlorides manufactured in
layers, more or less deep, and in a state of rest, and a source of considerable loss is
thereby avoided in the manufacture of this product, which is liable to deterioration
from the influence of climate and other influences resulting from its compo-
sition.