CERTAIN IMPROVEMENTS IN THE METHOD OF BLEACHING, AND IN THE APPARATUS CONNECTED THEREWITH
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PIERRE
ISIDOR DAVID, of Paris, in the Empire of France, Machinist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fifth day of February, One thousand eight hundred and
fifty-three, and in the year of our Lord One thousand eight hundred and
fifty-three, did, for Herself, Her heirs and successors, give and grant unto
me, the said Pierre Isidor David, Her especial license, full power, sole
privilege and authority, that J, the said Pierre Isidor David, my exors,
adiors, and assigns, and such others as I, the said Pierre Isidor David,
my exors, admors, or assigns, shall at any time agree with, and no others,
from time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "CERTAIN
IMPROVEMENTS IN THE METHOD OF BLEACHING, AND IN THE APPARATUS CONNECTED
THEREWITH;" in which said Letters Patent is contained a proviso that I, the
said Pierre Isidor David, shall cause a particular description of the nature
of my said Invention, and in what manner the same is to be performed,
to be enrolled in Her Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Pierre Isidor David, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, is particularly
described and ascertained in and by the Drawings hereto annexed, and the
following explanation thereof (that is to say):-
My improvements in the method of bleaching, and in the apparatus con-

page_text: nected therewith, are applicable to the bleaching of cotton, either in the raw
state or more particularly when manufactured into yarn or thread, and either
in the "cop" or the "hank." The bleaching is effected by means of chlorine
gas, and whilst the cotton is in a dry state or nearly so. The chlorine gas is
obtained from a solution of chloride of lime in water, into which a shower of
diluted sulphuric acid is allowed to fall through suitable perforations, the
solution of chloride of lime being at the same time gently agitated. The
chlorine gas thus liberated is washed and purified by being caused to pass
through water, and subsequently through sulphuric acid placed in suitable
vessels. The cotton being placed in convenient cages or receptacles, is sub-
mitted in a close vessel to the action of dry steam, and if required, of ammo-
niacal gas, in order to prepare it for the bleaching process. The cotton, &c.
is now to be placed in a receiver or bleaching cylinder, which is securely
closed. The chlorine gas, purified as above stated, is then admitted to the
lower part of the receiver, the air being allowed to escape through a stopcock.
As soon as the cotton is sufficiently bleached, which will be when the gas has
penetrated to the top of the chamber, the gas and escape pipes are closed, and
the chlorine gas is then exhausted from the cotton by means of an air pump.
Whilst the exhaustion is going forward, a tap communicating from the receiver
to a vessel containing strong liquid ammonia is to be opened for a sufficient
length of time according to the judgment of the operator for the purpose of
destroying the effect of any chlorine or hydrochloric acid upon the cotton.
When a sufficient vacuum has been obtained, the action of the air pump must
be stopped, and atmospheric air admitted through a valve provided for that
This exhaustion and readmission of air may be repeated as often as
thought necessary. The cotton may then be withdrawn from the receiver,
and after having been again subjected for a short time to the action of the dry
steam, and if required of ammoniacal gas, the operation is complete. In order
that the practical construction of my improved apparatus may be more
clearly understood, I have attached to these Presents a Sheet of Drawings
illustrative of the same, and have marked the same with figures and letters of
reference corresponding with those in the following description thereof.
purpose.
Fig. 1 represents a sectional view of the steam chamber; Fig. 2 is a
longitudinal elevation of the remainder of the apparatus; and Fig. 3 is a
section of the gas generator. In Fig. 1 a, a, represents a vessel of suitable
material, and inclosed by means of a conical cover b, b, the lower edge of the
said cover dipping into a recess formed around the rim of the vessel, and filled
with lute. c, c, is a coiled perforated pipe furnished with a stopcock for
admitting steam to the vessel a, a; and d, d, is a pipe for the egress of the

page_text: steam therefrom.
e, c, is the cage or receptacle in which the cotton is placed;
and f,f, is a small dish suspended therefrom (containing ammonia in a state of
powder, and furnished with a perforated cover. A cage filled with cotton
being placed in the vessel a, and steam admitted, the cotton will thus become
heated and saturated with ammoniacal gas. In Figs. 2 and 3 a, a, represents
the chlorine gas generator, which is lined or coated in the interior so as to resist
the action of the sulphuric acid, &c. This generator is furnished with a man-way
at b, b, through which is introduced a solution of ordinary "bleaching powder"
or chloride of lime in water. This solution is kept in gentle motion by means of
the agitator c, c, which is caused to revolve slowly by means of the gearing d, d.
There is a shallow perforated dish e, e, of lead or other suitable material in the
interior of the generator; into this dish e, e, diluted sulphuric acid is admitted
from a cistern or reservoir above by means of a pipef,f, which is provided with
a stopcock. As the diluted acid is admitted, it is distributed in a slight shower
by means of the perforations, and solution of chloride of lime being kept
in gentle agitation, a constant and equable liberation of chlorine gas takes
place. 9, 9, is a valve or plug for discharging and washing out the generator.
h, h, is the pipe which conveys the gas to the purifyer, and is furnished with a
stopcock i. The purifyer consists of three or more vessels k¹, k², and, of glass
or other suitable material. The first vessel k' contains water, and the remain-
ing vessels contain sulphuric acid. The vessels are connected together by
means of curved pipes 1, 7, the pipes being so arranged that the gas is compelled
to ascend through the water or acid in the vessels. The vessel le¹ is furnished
with a glass or other tube m,m, the rising of the water in which indicates
the pressure of the gas in the purifier. Should the water rise too high
in the tube m, owing to the too rapid evolution of the gas, a portion of
the gas may be allowed to escape by opening the cock or tap j. The pipe n, n,
communicates from the last vessel of the purifier to the lower part of the
receiver or bleaching cylinder o, o, and is provided with a stopcock p. The
window for inspecting the process is situated at q. v, r, represents the tap and
pipe for the exit of the air from the receiver at 8, s, the valve for the admis-
sion of air to the cylinder. t, t, is the air pump, and u is the vacuum valve,
which is balanced by means of the weight v, and weighted by means of the
lever and weight w, w, when required. x is the vessel to contain the liquid
ammonia, being provided with a pipe and stopcock y, y. The operation of
bleaching by means of this apparatus is as follows:-The cotton to be bleached
having been submitted to the action of the steam and ammoniacal gas in the
vessel a, Fig. 1, is placed in the cages or receptacle in the receiver o, o, which
is then closed. The air valves and the vacuum valve u being also closed,

page_text: and the escape cap 7 opened, the purified chlorine gas is admitted into the
receiver o, o, by means of the stopcock p, the air in the cylinder escaping by
means of the pipe r. As soon as the gas has pervaded the whole of the cotton
in the cylinder, which can be readily perceived through the window 9, the
cocks p and r must be closed, the weight w removed from the vacuum valve u,
and the air pump t, t, set in motion by any suitable means. During the
process of exhaustion the stopcock y is to be opened, the vacuum causing the
liquid ammonia to boil and evaporate quickly, and neutralize any deleterious
effect that the remaining chlorine or hydrochloric acid might have upon the
cotton. When a sufficient vacuum has been obtained, which may be readily
ascertained by having a vacuum guage affixed to the receiver, the valve s is to
be opened, and a current of air is thus allowed to rush through the cotton, &c.
This exhausted and readmission of air may be repeated until all traces of the
chlorine are removed. The cotton is for a few minutes again subjected to the
action of steam in the steam box. The operation is then complete.
Having thus described the nature and object of my said Invention, together
with the manner of carrying the same into. practical effect, I would remark,
in conclusion, that I claim as my Invention,-
First, the method of bleaching by means of chlorine gas, as above described;
and,
Secondly, the apparatus shewn in the Drawings, or any modification thereof,
for effecting the said object.
In witness whereof, I, the said Pierre Isidor David, have hereunto set
my hand and seal, the Second day of August, One thousand eight
and G... thron
PIERRE ISIDOR (L.S.) DAVID.
Taken and acknowledged by the within-
named Pierre Isidor David, at Dieppe,
in France, as his act and deed, and by
him desired to be enrolled, this Second
day of August, One thousand eight
hundred and fifty-three, before me,
GEO. CHAPMAN, British V. Consul.