AN IMPROVED PROCESS OF BLEACHING, AND APPARATUS TO BE EMPLOYED FOR THE PURPOSE, PART OF SUCH PROCESS BEING ALSO APPLICABLE TO FINISHING
Year: 1883

page_text: LETTERS PATENT to Jacob Baynes Thompson, of New Cross, in the County
of Kent, for an Invention of AN IMPROVED PROCESS OF BLEACHING, AND
APPARATUS TO BE EMPLOYED FOR THE PURPOSE, PART OF SUCH PROCESS
BEING ALSO APPLICABLE TO FINISHING,"
6
PROVISIONAL SPECIFICATION left by the said Jacob Bayues Thompson
at the Office of the Commissioners of Patents on the 3rd February 1883.
JACOB BAYNES THOMPSON, of New Cross, in the County of Kent, AN IMPROVED
PROCESS OF BLEACHING, AND APPARATUS TO BE EMPLOYED FOR THE PURPOSE,
PART OF SUCH PROCESS BEING ALSO APPLICABLE TO " FINISHING,"
My Invention has for its object the bleaching of yarus, threads and textile
fabrics of vegetable fibre, in a more efficacious and expeditious manner than
heretofore, and by means of the agents hereinafter mentioned.
In bleaching linen fabrics according to my Invention, I proceed as follows. I
boil the fabric for about 3 hours in a solution of cyanide of potassium or sodium
say 1/2 oz of the salt to the gallon of water, in order to remove the resinous matter
from the linen fibre so that the cellulose may be exposed to the bleaching agency
of the chlorine. The fabric is then washed and again boiled for 3 hours more in
a similar solution. It is then washed again and is ready for bleaching.
With cotton, this preliminary boiling is not necessary, except in rare cases when
grease or oil may have come in contact with it, and then it requires the solution
to be only half strength, and to be boiled for about 2 hours. In ordinary cases,
cotton is not boiled at all, it is simply washed in cold water and squeezed.
In bleaching, all vegetable fibres or fabrics are treated similarly, the only
difference being difference of time.
The cotton or linen after being treated as above described, is piled somewhat
loosely in a suitable air tight vessel; 9 lbs of cloth to the cubic foot of space being
considered sufficient. The vessel is then filled with a weak solution of the
bleaching liquor, of a sp: gr: of 10012 to 10015, or about 1/ Baumé; about 1 oz,
dry bleaching powder, to the gallon will give this strength. After the vessel has
LD C
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page_text: been filled, the liquor is immediately run out, and is replaced by an atmosphere of
carbonic anhydride (commonly called carbonic acid) which quickly liberates the
chlorine on the fibre, and this decomposes the water, uniting with the hydrogen
and liberating the oxygen, the result of which is to bleach the fibre or fabric.
In about one hour, the whole of the bleaching liquor on the fibre will have been
thus decomposed, and this operation must be repeated until the material is of the
proper whitness to be withdrawn from the action of the chlorine. The material
is then washed and squeezed. Chlorine, however, always leaves these materials of
a yellowish white, part of which is caused by a trace of ferric oxide, which it will
acquire even in the course of manipulation. To remove this yellowish tint the
material is passed through a solution of oxalic acid, (about 2 oz to the gallon)
squeezed as it passes out of this solution, and then passed through another solution
which is made by dissolving, in water, Triethylroseaniline, indigo, or other similar
compound. If triethylroseaniline be used, about 1/4 grain to the gallon will be
found sufficient, and if indigo be used about 20 grains to the gallon will be
required. To this solution must be added oxalic acid till it becomes of an opaque
but bright turquoise blue. The material having been passed through this solution
is then washed and will be found to be of a pearly white
These two latter solutions may be advantageously used in what is technically
termed "Finishing" in the above class of fabrics.
An apparatus suitable for carrying out my improved proce-s consists of a
bleaching vessel which may be of any convenient shape or size and may be made
of wood; it is so arranged that the cover can be easily made air-tight. At the
bottom of this vessel there is a U-shaped leaden pipe provided with tap or spigot
to retain the liquor till the vessel is full. At the upper part of this vessel is a pipe
(with stop cock), leading from a gas holder, which contains the carbonic acid.
Also at the upper part of this vessel, but on the opposite side, there is another pipe
(with stop cock) leading from the bleach-water tank. The gas holder is of the
ordinary kind. The gas may be generated in any convenient manner, for example
in the same manner as carbonic acid is generated for the manufacture of
bi-carbonate of soda. If desired the linen fibre or fabric after being bleached may
be frozen in any suitable freezing apparatus for the purpose of enhancing its
whiteness.
The apparatus herein described is intended to be used in conjunction with
certain parts of the existing apparatus used in bleaching.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jacob Baynes Thompson in the Great Seal Patent Office on the
3rd August 1883.
JACOB BAYNES THOMPSON, of New Cross, in the County of Kent, AN IMPROVED
PROCESS OF BLEACHING, AND APPARATUS TO BE EMPLOYED FOR THE PURPOSE,
"
PART OF SUCH PROCESS BEING ALSO APPLICABLE TO FINISHING
"
My Invention relates to an improved process of bleaching, and to apparatus for
the purpose, part of such process being also applicable to that step in such process
or art technically termed "Finishing," and my Invention has for its object the
bleaching of yarns, threads, and textile fabrics of vegetable fibres, in a more
efficacious and expeditious manner than heretofore.
In bleaching linen fabrics according to my process, I proceed as follows. I boil
the fabric for about 3 hours in a solution of cyanide of potassium, or sodium (say
oz. of the salt to the gallon of water) in order to remove the resinous matter
from the fibre, so that the cellulose may be exposed to the subsequent bleaching
action, as hereinafter described. The fabric is then washed and again boiled for
3 hours more, in a similar solution. It is then washed again, and is ready to be
bleached.
With cotton fabrics, this preliminary boiling is not necessary, except in rare
cases, when grease or oil may have come in contact with the material, and then
the solution should be of about half the previous strength, and the material should
be boiled for about 2 hours. In ordinary cases, cotton is not boiled at all, it is
simply washed in cold water and squeezed.
In bleaching, all vegetable fibres or fabrics are treated similarly, the only
difference being difference of time of exposure to the bleaching agent.
The cotton, or linen, after having been treated as above described is placed
somewhat loosely in a suitable air-tight vessel (9 lbs. of the cloth to the cubic foot
of space being considered sufficient) and the vessel is then filled with a weak
solution of the bleaching liquor of a specific gravity of 10012 to 1·0015, or about
1 Beaumé (from oz. to 1 oz. dry bleaching powder, that is, chloride of lime, to
the gallon of water will give this strength). After the vessel has been filled the
liquor is immediately run out and is replaced by an atinosphere of carbonic
anhydride (commonly called carbonic acid) which quickly liberates the chlorine on
the fibre, and this decomposes the water, uniting with the hydrogen and liberating
the oxygen, the result of which is to bleach the fibre or fabric.
In about 1 hour the whole of the bleaching liquor on the fibre will have been
thus decomposed, and this operation of moistening the material afresh, and then
subjecting it to the action of the gas, should be repeated as many times as may be
necessary, until the material is of the proper whiteness to be withdrawn from the
action of the chlorine. The material is then washed and squeezed. Chlorine,
however, always leaves these materials of a yellowish white, part of which is
caused by a trace of ferric oxide which it will acquire even in the course of mani-
pulation. To remove this yellowish tint, and to enhance the whiteness, the
material is passed through a solution of oxalic ac'd (about 2 oz. to the gallon of
water) and is squeezed as it pass s out of this solution, and is then passed through
another solution, which is made by dissolving in water, triethylroseaniline (com-
monly called amline violet in commerce) indigo, or other similar compound. If
triethylroseaniline be used, about 1 to 1 grain to the gallon will be found
sufficient, and if indigo be used about 20 grains to the gallon will be required, but
I prefer to use triethylroseaniline. To such solution oxalic acid is added till it

page_text: becomes of an opaque but bright turquoise blue: about 4 oz. acid, to grain aniline.
Or the material may be passed through the aniline violet, and then be squeezed
and passed through an oxalic acid solution of the strength above mentioned, and
again be squeezed and finally be washed and finished, when it will be found to be
of a pearly whiteness.
These two latter solutions, viz, the aniline violet and the solution of oxalic acid,
may be advantageously used in what is technically termed "Finishing" in the
above class of fabrics.
And in order that my Invention may be more readily understood, I proceed to
describe the same with reference to the accompanying drawings, in which the figure
represents a perspective view of apparatus suitable for the purpose.
A, is an upper tank containing bleach liquor, and B a lower tank, also containing
bleach liquor. C is the air tight bleaching vessel or tank, and D, a gas holder.
a, is a pipe leading from the upper tank A, and b, a U-shaped pipe, to show when
the bleaching vessel is full. c, is another U-shaped pipe to allow the bleach liquor
to run out, but to keep the bleaching vessel sealed against the escape of the gas.
d, is an opening into the bleaching vessel C, through which the materials in it may
be examined, in order to ascertain whether they are ready to be withdrawn.
e, e, are bolts with lever nuts, to secure the cover f, of the bleaching vessel air-tight.
9, is a pipe leading to the gas holder. h, is a chain of a differential pulley, by
means of which the cover f may be raised. i is a pipe from the pump, and j is the
Jump, which pumps the liquor from the lower to the upper tank. k, is a pipe to
run off the water, when the bleaching vessel is filled with it, and is a perforated
false bottom to support the material; there is also a pipe entering at the top of the
bleaching vessel, not shewn in the drawings, by means of which the vessel is filled
with water.
The working of the process is as follows:-
After the preliminary singeing and washing, and with linen, after boiling and
washing, the fabric is packed loosely in the vessel C, preferably in the proportion
herein before mentioned. The cover f is then screwed down airtight, the air tap,
not seen in the drawing, is opened at the top of the bleaching vessel, and the
bleaching liquor is run in till the vessel is full, the air tap is then closed and the
gas being turned on at g, and the spigot or plug inserted in pipe c, the flow of the
liquor is turned off at a, and the spigot is removed from pipe c. After standing
about an hour, the spigot is again inserted, and the bleaching liquor turned on, and
as soon as the vessel fills, the gas will be driven back into the gas holder, till the
bleaching vessel is again full of liquor, and the manipulation is gone through as
before, the same gas serving over and over again, the only loss being that absorbed
by the small quantity of water it comes in contact with, and by leakage, if there
be any.
The gas readily displaces the chlorine which is held loosely by the hydrate of
lime, and forms carbonate of lime or chalk; but the chlorine on being liberated
decomposes the water, and unites with the hydrogen and forms hydrochloric acid,
and this, in turn, displaces the carbonic acid from the lime, and forms calcium
chloride, so that the carbonic acid gas is again ready to perform its office.
When the material is thought to bo white enough to be removed from the
bleaching vessel, water is run into such vessel, in order to drive the gas into the
gas holder.
The tap g, is then closed, and the water run out at ke, the material
can then be examined at 'the test-hole d. If the material be found to be white
enough, the test-hole is closed, and the cover unscrewed, and raised by the chain
and pulley, and the material taken out of the vessel, washed and squeezed. The
material is then passed through the blue liquor and squeezed, and then through the
solution of oxalic acid and squeezed, and finally washed. If it be not quite of the
brilliancy required, it is again passed through the blue liquor, squeezed, and passed
through the oxalic acid solution and washed, but usually once will be found
sufficient.
In using triethylroseaniline in "Finishing," the starch is tinted with it, about

page_text: grain to the gallon, and oxalic acid is added, till it is of the tint required, in the
operation of "Finishing," as ordinarily practised, or the turquoise blue may be
prepared apart from the starch and added afterwards.
If desired the linen fibre or material after being bleached, as above described,
may be frozen in any suitable freezing apparatus for the purpose of enhancing its
whiteness.
Having now described the nature of the said Invention, and in what manner the
same may be performed, I declare that I claim.―
1. The process herein desired [sic] of bleaching linen and cotton fibres or fabric-
consisting in first boiling in a solution of cyanide of potassium, washing in water,
bleaching in a closed vessel with a chloride of lime solution and carbonic acid gas,
and subsequently treating with a solution of oxalic acid and triethylroseaniline in
water, and finishing with a solution of oxalic acid, for giving a final enhanced
whiteness to the fibres or fabrics, substantially as and for the purposes set forth.
2. The process herein described of bleaching linen and cotton fibres or fabrics
consisting in subjecting the same to the action of a solution of chloride or lime and
water, in a closed vessel, discharging said solution of chloride of lime and subjecting
the said material to the action of an atmosphere of carbonic anhydride, or carbonic
acid gas, and alternating the rewetting said fibres or fabrics with the solution of
chloride of lime and subjecting the same to an atmosphere of carbonic acid gas,
until the fibres or fabrics have been bleached to the desired degree of whiteness
and then subjecting said bleached fibres or fabrics to the action of a solution of
triethylroseaniline, or similar compound, in conjunction with oxalic acid and water,
and lastly, passing said fibres or fabrics through a solution of oxalic acid and
water, substantially as specified.
3. An apparatus for bleaching linen and cotton or other vegetable fibres or
fabrics composed of the tanks A and B for the bleaching liquor, the bleaching
vessel C, the gas bolder D, the pipe a, connecting vessels A and C, the pipe g,
connecting vessel C and holder D, discharge pipes b, c, from the vessel C, and
a pump j, for transferring the liquid from vessel B to vessel A, substantially as
shewn and described.
4. In the process of "Finishing" the use of a solution composed of triethylrose-
aniline and oxalic acid for the purpose of tinting the starch.
In witness whereof I the said Jacob Baynes Thompson have hereunto set my
hand and seal this Second day of August in the year 1883.
T D THOMPSON