Improvements relating to the Production of Liquid Chlorine, and to Apparatus therefor.
Year: 1892

page_text: Date of Application, 2nd Jan., 1892-Accepted, 2nd July, 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by ELISHA BARTON CUTTEN, 29, Broadway, of
the City, County, and State of New York, United States of America,
Chemist.]
Improvements relating to the Production of Liquid Chlorine, and to
Apparatus therefor.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings in the County of Middlesex, 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:-
The invention consists in a new method and apparatus for the production of
chlorine in liquid form, and its storage in suitable flasks or other receptacles from
which it may be drawn for any desired utilization.
My process broadly stated consists first in thoroughly dehydrating chlorine gas
and subjecting it to sufficient pressure to reduce it to a liquid. The result is the
production of anhydrous liquefied chlorine which, so far as I know, is an entirely
new product. It has long been known to chemists that chlorine may be liquefied
by subjecting it to a sufficiently high pressure or a sufficiently low temperature,
but up to the present time, so far as I am aware, this has only been done on a very
small scale, and by means which are only suitable to laboratory usage.
The principal obstacle in the way of making and selling liquid chlorine in the
market is found in the heavy pressure required to liquefy it. The pressure
increases with ordinary temperature. The result is that the liquefied chlorine
cannot be safely carried in vessels of glass or earthenware, while vessels or tanks
of metal having sufficient strength become rapidly corroded, and so weakened and
rendered useless and even dangerous. I have found that if the chlorine be rendered
anhydrous and then forced into a metallic vessel which is perfectly dry within, no
corrosion of the vessel will occur, and that the chlorine may not only be liquefied,
but stored and transported in the liquid condition.
It is not essential to my hereinafter described process that the chlorine should
be prepared in any particular way, but I find it better to obtain it in as pure a
state as possible. To this end I prefer to avail myself of the process of electro-
lytic decomposition of common salt which is fully disclosed and described in another
application for Letters Patent, of even date herewith, as I find that the chlorine
thus obtained is of a high degree of purity and excellently well adapted to the
treatment hereinafter set forth.
In the accompanying drawings,
Figure 1 shows, partly in elevation and partly in vertical section, an apparatus
for carrying my aforesaid process into practical effect.
Figure 2 shows a steel cylinder or flask for storage of liquid chlorine.
Figure 3 shows a mode of utilizing liquid chlorine to make a bleaching
solution.
Figure 4 shows the mode of drawing off liquid chlorine from the storage
cylinder.
Similar letters of reference indicate like parts.
Referring more particularly to Figure 1, at A. is shown two electrolytic cells of
the invention. These are especially adapted to the production of caustic soda
and chlorine by the electrolysis of sodium-chloride: the chlorine being obtained in
an unusually pure state.
The outer tanks or vessels, a, of these cells, are of iron and must be directly

page_text: connected to one terminal of the dynamo or other source of electricity so as to
form a cathode, this connection being indicated diagrammatically at d. The anode
in the cell is a rod, c, of carbon, which is inserted in a block of similar material
which is held in a cup as shown, which cup rests upon a horizontal_partition, f,
which is made of glass and which is located at the bottom of the vessel a.
j
bis a bell which may be of glass and which is supported by the pipe b' which
extends from the chlorine main B. At the bottom of the vessel, a, are troughs or
channels, 9, which receive the heavy solution after electrolysis. When the interior
of the cell is filled with chloride of sodium, and a strong solution of the same salt
is also placed in it, and when the current is established, chlorine is produced at the
anode, c, and sodium at the cathode, a. When the sodium combines with one
equivalent of oxygen and hydrogen due to decomposition of the water to form
caustic soda, the soda descends along the wall of the outer vessel down through
the mass of salt and accumulates in the lower portion, e, of the tank, a, beneath the
glass plate, f, and is drawn out at the channel, y. The chlorine which is generated
at the anode, c, is drawn by the action of the pump, hereinafter explained, through
the short pipes b' and into the chlorine main, B. From the main, B, the gas goes
to a condenser C. This consists of a chamber j, having numerous vertical tubes, i.
The chamber is kept filled with ice water which enters by the pipe j', and may be
drawn off at the pipe as soon as it is heated. The chlorine passes upwards, as
indicated by the arrows, through the tubes, i, when most of the moisture which it
holds in suspension is condensed, and runs down into the chamber h at the bottom
of the condenser. Thence it may be drawn off into the vessel k, which is preferably
made of glass. The accumulated water may be drawn off from vessel k from time
to time by closing the cock 41, opening the air-vent k³, and opening the discharge-
cock. The condenser C should be made of glass, glazed earthenware, or of lead.
The gas now passes from condenser C to one or more dehydraters D. These
dehydraters are compartments having several shelves m, on which is placed a
quantity of calcium chloride in granular form, indicated at 1. The effect of the
chloride of calcium is to remove the larger portion of whatever moisture may
remain in the gas after it has been acted upon by condenser C. This part of the
apparatus may be made of lead, since the chlorine is already partially dried, and
hence its corrosive action is reduced. From the dehydrater the gas continues
through a pipe F, which is provided with numerous branch pipes, as n.
pipe, n, leads to the bottom of a vessel E, of which there may be several, and each
vessel, E, connects by short pipes, p, with the main G. I place sulphuric acid in
each one of the vessels, E, and as the pipe n extends below the level. of the acid,
the gas necessarily bubbles up through it. The effect of the acid is to remove any
last remaining moisture which the gas may hold which has escaped the action of
the, dehydrater. The flow of the gas into the receiving chamber H is regulated by
the valve q
The receiving chamber H connects by a pipe having a valve r
with the compressing pump J. This pump must be made of a material which is
not capable of combining chemically with anhydrous chlorine.
Each
The object of the chamber H is to afford a reserve of gas, from which the pump
may draw in order that the pulsations caused by the strokes of the pump shall
not be transmitted back by the pipes G and F through the various parts of the
apparatus, this being prevented by making the chamber H of sufficient capacity,
and adjusting the valve q to choke back the admission of gas into the chamber.
The compressing pump J forces the compressed gas through the pipe into a
receiving tank K, which is preferably of steel. This is provided with a relief
valve and an outlet cock u. It also contains a coil or pipe L through which
may be forced by any convenient means cold water or other refrigerating liquid,
the pipe L operating after the well-known manner of such cooling devices as are
used in ice making, and other refrigerating machines.
The outlet being normally closed, a pressure is caused by the pump J in the
tank K sufficient to liquefy the chlorine, the heat due to compression meanwhile

page_text: v
being abstracted by the cooling coil L. The tank or cylinder for holding the
liquefied chlorine is shown at M, and is connected by the union to the outlet u
of the tank K. It is provided with a cock which by means of the union vis
connected to a safety valve t¹ set to a pressure in excess of that to which the
liquefied chlorine will evaporize. The tank K is provided with a gauge r, and a
similar gauge is connected to the safety valve t'. In the upper part of the
cylinder M is a valve w which communicates with a pipe to leading to the bottom
of the cylinder.
The operation of drawing off liquefied chlorine into the cylinder M is as
follows: The compressed chlorine enters the cylinder and compresses the air
therein until the air pressure in the cylinder and in the tank K reach equilibrium.
The valve is then opened to allow the air to escape to the safety valve t¹ which
is set to a lower pressure than the safety valve x on the cylinder K. Since the
outlet u draws from the bottom of the tank K only liquid chlorine escapes. As
soon as the pressure in the cylinder M has reached 60 pounds or thereabouts to
the square inch, it is certain that the chlorine admitted therein is in liquid form
because any of it which may have been vaporized when first admitted has become
re-condensed to a liquid. Meanwhile, the action of the condenser J keeps up the
pressure in the cylinder M and this causes the confined air to be forced out of the
safety valve ¹. When the cylinder M is full, the valves and we are closed, and
the unions u¹ and are disconnected when the cylinder is ready for shipment.
When the chlorine gas is generated by the electrolytic process of decomposition
of sodium chloride, it may be diluted with small quantities of oxygen and atmo-
spheric air. These foreign substances are separated from it in the tank K; as the
chlorine after compression to about 60 pounds to the square inch and on being
cooled liquefies, it necessarily becomes separated from the oxygen and air, and the
latter accumulates in the top of the tank above the body of liquid chlorine. The
safety valve t is set to a pressure sufficient in excess to that at which the chlorine
liquefies at the temperature at which it is introduced into the tank, to insure that
all the chlorine shall be liquefied before the pressure is raised sufficiently to open
the valve.
It follows that as the tank is nearly filled and as the pressure 18 increased
the valve t will be lifted, and the air and oxygen will escape. By reason
of the specific gravity of the chlorine, very little or any of it, even in gaseous
form, will escape at the valve t, but should any appear the discharge from the
condenser J may be turned into another tank, or the pressure in the tank K may
be relieved by allowing the escape of its contents into a cylinder, as M.
In Figures 3 and 4, I illustrate two modes of using my cylinder M after it has
become charged with liquid chlorine.
In Figure 3 a pipe y connected to the valve w of the cylinder leads to a tank T
containing water. On opening the valve w, the liquid chlorine is forced out and
into the water, where it may be mixed by suitable stirrers, as shown. When the
water becomes sufficiently charged with chlorine, ingress of the latter is stopped
and the chlorinated water may be used in the ordinary way as a bleaching
material.
Figure 4 shows the mode of drawing the liquid chlorine from the cylinder M.
The cylinder is inverted and the liquid is drawn off like water from the cock v
into the receiving vessel z, by which it may be measured in suitable quantity and
added to the water in the tank as shown.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. The method of, and apparatus for producing liquefied chlorine, substantially
s hereinbefore set forth, operated and arranged to effect dehydration of chlorine
gas and then its liquefaction by means of pressure, or pressure and low temperature
combined.

page_text: 2. The construction and arrangement of the chlorine liquefying apparatus,
herein before described, whereby dehydrated chlorine in liquid form is delivered
into and stored in closed receptacles suited for its transportation.
Dated this 2nd day of January 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.