IMPROVEMENTS IN BLEACHING
Year: 1884

page_text: We, CHARLES FREDERICK CROSS, of No 1, The Mall, Brentford, in the County of
Middlesex, Chemist, and JAMES PELLATT RICKMAN, of 17 Saint Bride Street, in
the City of London, Glass Manufacturer, do hereby declare the nature of said
invention for IMPROVEMENTS IN BLEACHING, to be as follows:-
Our Invention relates to improvements in bleaching certain vegetable fibres and
fabrics, more especially cotton and linen goods, whereby the bleaching. of such
substances or materials. is effected with much greater rapidity than heretofore.
In carrying out our process, we use chlorine gas, and we intensify and limit its
action by saturating the material to be bleached with an aqueous solution of an
alkali or basic compound, such for example as caustic soda. We bring the resulting
well known chemical reaction within the range of industrial application, as
follows:
:
The fabrics to be bleached having been previously boiled or treated, by the.
ordinary methods of preparation for bleaching, such as boiling with lime or
alkaline solutions, are immersed in a solution of caustic soda and then freed, either.
by pressure, or otherwise, from the excess of liquid.
In this condition the goods are piled in an airtight kier, or other suitable air
tight vessel, and the air in such vessel is then withdrawn by means of an exhaust
pump, or otherwise, and a sufficient supply of chlorine. gas is allowed to enter.
The action of the gas may be intensified by forcing it in under pressure.
Or we produce the desired result, in the case of piece goods which can be treated
in a continuous length, by passing them alternately through a solution of caustic
soda and an atmosphere of chlorine gas, preferring for this purpose to use such an
apparatus as that described by W Mather, in his Provisional Specification, N° 7909,
dated 19 May 1884.
It is important that the vessels containing the chlorine gas should be suitably
protected from corrosive action, by lining or coating, and that any internal fittings
or appliances should be, in like manner, protected as may be necessary.

page_text: We, CHARLES FREDERICK CROSS, of No 1 The Mall, Brentford,, in the County of
Middlesex, Chemist, and JAMES PELLATT RICKMAN, of 17 Saint Bride Street, in the
City of London, Glass Manufacturer, do hereby declare the nature of said invention
for IMPROVEMENTS IN BLEACHING, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,
that is to say:-
Our Invention relates to improvements in bleaching certain vegetable fibres and
fabrics, more especially cotton and linen goods, whether in the raw or dyed condition
or state, whereby the bleaching of such substances or materials is effected with
much greater rapidity than heretofore..
In carrying out our process we use chlorine gas and we intensify and limit its
action by saturating the material, or portion thereof, to be bleached, with an aqueous
solution of an alkali or basic compound, such for example as caustic soda.
We bring the resulting well known chemical reaction within the range of
industrial application, as follows:
The fabrics or vegetable substances to be bleached having, in the case of raw
goods, been previously boiled or treated by the ordinary methods of preparation
for bleaching, such as boiling with lime or alkaline solutions, or steaming, in
accordance with the provisions set forth in the specification of British 'Letters
Patent granted to one of us, viz, to me the said Charles Frederick Cross, on the
30th November 1880, and numbered 4984, are immersed in a solution of caustic
soda, carbonate of soda, or milk of lime, or other basic solution, according to the
extent of action which it is desired to determine. As a convenient working
standard we employ a solution containing in 100 parts 1 part, by weight, of
alkali (Na, O). The excess of solution is then removed by draining, squeezing or
otherwise.
The goods are then piled in an air tight kier, or other suitable vessel, and the air
in such vessel is then withdrawn by means of an exhaust pump, or otherwise, and
a sufficient supply of chlorine gas is allowed to enter. The alkalised goods or
substances are allowed to remain in contact with the chlorine gas until the action
is completed. This treatment may be repeated if necessary, the goods or substances
being preferably alkalised in the kier or vessel, and the alkaline solution may be
used to displace the chlorine which is caused to return to a suitable reservoir
where it is available for further use in the second operation which consists in again
exposing the goods or substances to the chlorine atmosphere after the excess of
alkaline solution has been allowed to drain, away. This alternate treatment may
be repeated at pleasure and varied in any way according to the circumstances of
the case, without departing from the nature of the invention.
For carrying out this process as thus described, we prefer to use similar apparatus
to that described in the specification of the British Letters Patent granted to
Jacob Baynes Thompson on the 3rd day of February 1883, and numbered 595,
which has the advantage of maintaining the gaseous atmosphere under a certain
pressure and thus intensifying its action.

page_text: But we may produce the desired result, in the case of piece goods, which can be
treated in a continuous length by passing them alternately through a solution of
caustic soda, or other basic solution, as above described (removing the excess of
solution by causing the goods-to pass through squeezing rollers) and thence into an
atmosphere of chlorine gas, preferring for this purpose to use such an apparatus as
that described by William Mather, in the specification of his British Letters Patent
N° 7909, dated 19 May 1884. It is obvious that by means of such an apparatus
we can also effect the partial bleaching, or as it is technically termed "the topical
discharge" of dyed or printed colours, i,e, by topically applying the alkaline
solution in any of the known ways, the portions so treated yielding to the gas
during a passage of only some few seconds.
It is important that the vessels containing the chlorine gas should be suitably
protected from corrosive action by lining or coating, and that any internal fittings
or appliances should be, in like manner, protected as may be necessary.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, we declare that what
we claim, is
1. The herein described process of bleaching vegetable fibres, fabrics or
substances, consisting in treating the same, in a suitable vessel or apparatus, with
chlorine gas in presence of an alkali, the alkali being previously applied in
solution in water to the material to be bleached, substantially as set forth.
2. The application of the process as herein described to the discharge of colours
from printed or dyed fabrics.