Improvements in the Process of and Apparatus for Bleaching Vegetable Fibres.
Year: 1890

page_text: Date of Application, 5th Apr., 1890
Complete Specification Left, 5th May, 1890-Accepted, 14th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in the Process of and Apparatus for Bleaching
Vegetable Fibres.
I, CARL KELLNER, of Vienna, in the Austrian Empire, Chemist, do hereby declare
the nature of this invention to be as follows:-
The process of bleaching vegetable fibres which forms the subject of this invention,
is effected with the aid of electrolysis and it is based on the discovery that colouring.
substances adhering to the fibres are far more easily and rapidly converted into.
compounds soluble in water by alternately treating the fibrous material to be bleached
with chlorine or compounds containing active chlorine and alkalies..
This is to be ascribed to the fact that chlorine before it converts the colouring
substances into compounds soluble in water, gives rise to the formation of an inter-
mediary product, which, although not soluble in water, is easily soluble in alkalies.
Consequently, when the quantity of the said intermediary product formed by the
action of chlorine for a short time is washed away by a solution of alkali, and the
chlorine is afterward allowed to act again, not only will chlorine be saved, but the
bleaching will be effected in less time than is usual. This saving of chlorine and
the shortening of the duration of the process as compared with the process hitherto in
use is the more considerable as in bleaching with chlorine according to the usual
method, hydrochloric acid is formed, and consequently, the action of the chlorine must
be sufficiently prolonged that compounds soluble in acids are formed instead of
compounds soluble in water.
According to this invention, a chloride of an alkali is decomposed by electrolysis
and the anion and cathion are caused alternately to pass through two separate
quantities of the fibrous material to be bleached. Afterwards both ions are again
united and conveyed back into the electrolyzing apparatus.
As to the arrangements of the apparatus, which may be used to advantage in
carrying this process into practice, they may be made in the form of potcher engines.
A modified form of the apparatus giving good results, is composed of vats each having
three sides or concentric walls within the innermost space of which the fibrous
material to be bleached is continuously whirled up by a screw propeller so as to cause.
it to flow over the brim of the innermost lowest side of the vat into the adjacent
annular space, whence it passes back into the central space through openings formed
in the bottom portion of the innermost side. Either ion enters the central space of
the vat through a sieve bottom and afterwards flows out through the finely perforated
top portion of the middle side into the outer annular space, communicating with a
tank, where both ions again unite; the electrolyte recovered by the recombination of
both ions is again pumped into the electrolyzing apparatus. It is obvious that the
fibrous material may be caused to circulate through the said vats in the opposite
direction to that described, so as to rise within the annular space and sink within
the innermost space.
The annexed sheets of drawings represent bleaching apparatus arranged in the
manner just referred to.
Figs. 1 and 2 are a plan or top view and sectional elevation respectively, of an
apparatus comprising two potcher-engines which are so combined as to form one
body.
Figs. 3 and 4 are similar views of an apparatus provided with two separate potcher-
engines.
Fig. 5 is a sectional elevation of the bleaching apparatus comprising vats each

page_text: As clearly shown in Fig. 1, the trough of the combined potcher engines, which are
used in this case, is divided by two incomplete longitudinal partitions a a into three
compartments, viz. a central one band two lateral ones c c. Into the central com-
partment b, the fibrous material made up with a suitable quantity of water to a kind
of pulp, is continuously fed by means of the screw conveyor pump d, and flowing
down along the inclined sieve bottom e it passes under the paddle wheelf by which
the material is pushed forward so as to cause it to enter the lateral compartments c c ;
into one of these compartments the anion is conveyed through a perforated tube g,
while a similar tube g conveys the cathion into the other compartment. Flowing
down along the inclined bottom of the compartments c, the material reaches the
outlet apertures c¹ c¹ provided at the lowermost points, and thence it is taken up by
the screw conveyor pump d, which again delivers the mass into the central com-
partment b. In this manner both ions are united again, and the regenerated
electrolyte is conveyed by a pump into the electrolyzing apparatus j, in which it
passes through a sieve bottom before coming in contact with the electrodes, which
are made of platinum, carbon or zinc. Between the top portions of the successive
anodes and cathodes are arranged in complete cross partitions 13, and the open
bottomed cells which are thus formed by these incomplete cross partitions alternately
communicate with one and the other of two pipes g¹g extending along the outside
of the electrolyzing apparatus j. By this arrangement, one of the said pipes g' will
convey the anion to one of the perforated pipes g and the other pipe g¹ will convey
the cathion to the other perforated pipe g.
i
The apparatus represented by Figs. 3 and 4 differs from that described, by its
comprising two separate potcher engines kk. In either potcher-engine the fibrous
material to be bleached is caused to circulate by a suitably constructed cylinder k',
and the washing drums k³ ³ cause the solutions of the anion and the cathion, which
are conveyed to the potcher engines through the pipes gy, to enter the pipes 1, by
which they are again fed into the electrolyzer j. In this case, the direction of the
electric current is from time to time reversed in order to submit the fibrous material
to be bleached to the action of chlorine and alkali alternately.
This alternate reversal of the direction of the olectric current must likewise take
place when bleaching is performed with the aid of the apparatus represented
by Fig. 5. In this apparatus, the material to be bleached is brought into the central
spaces of two vats m n o, m n o each having three sides or walls and by means of a
screw propeller p arranged at the centre of the bottom, the said material is caused to
rise in a continuous manner within the central space and afterwards to sink down
again within the annular space between the walls m and n, for re-entering the central
space through openings m¹ provided in the bottom portion of the wall m.
As already stated, the fibrous material to be bleached may quite as well be caused
to circulate in the reverse direction so that it will continually pass from the central
space through the openings m¹ and afterwards rise within the annular space
between the walls m and n whence it passes over the top of m to flow downward
again.
The anion is supplied to the material under treatment through the sieve like bottom,
set with filter stones, of the central space of the one vat while the cathion is conveyed
through the similar bottom of the central space of the other vat, and through the
perforated top portion n' of the middle wall n, the said liquids flow into the annular
spaces between n and o. Thence both ions flow_into_a_collecting tank q and the
electrolyte thus partly recovered is pumped into the electrolyzer j of the described
arrangement.
Both vats are provided with covers o' hydraulically sealed at their rims and having
outlet pipes o for the gases evolved.
The apertures os provided with removable closures admit of the material under
treatment being inspected and samples withdrawn, while the steam pipes r afford
means for raising the temperature of the mass to the requisite point.

page_text: Instead of two vats, two series of vats may be used in combination with pipes for
connecting the vats with each other in a manner similar to the diffusers of diffusion
batteries; in this case the process is a continuous one.
Dated this 5th day of April 1890.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Process of and Apparatus for Bleaching
Vegetable Fibres.
I, CARL KELLNER, of Vienna, in the Austrian Empire, Chemist, 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 process of bleaching vegetable fibres which forms the subject of this invention
is effected with the aid of electrolysis, and it is based on the discovery that colouring
substances adhering to the fibres are easily and rapidly converted into compounds
soluble in water by alternately treating the fibrous material to be bleached with
chlorine or compounds containing active chlorine and alkalies.
This is to be ascribed to the fact that chlorine, before it converts the colouring
substances into compounds soluble in water, gives rise to the formation of an inter-
mediary product, which, although not soluble in water, is easily soluble in alkalies.
Consequently, when the quantity of the said intermediary product formed by the
action of chlorine for a short time is washed away by a solution of alkali, and the
chlorine is afterward allowed to act again, not only will chlorine be saved, but
the bleaching will be effected in less time than is usual. The saving of chlorine and
the shortening of the duration of the process as compared with the process hitherto
in use are the more considerable as in bleaching with chlorine according to the usual
method, hydrochloric acid is formed, and consequently, the action of the chlorine
must be sufficiently prolonged that compounds soluble in acids are formed instead of
compounds soluble in water.
According to this invention a chloride of an alkali is decomposed by electrolysis
and the anion and cathion are caused alternately to pass through two separate quantities
of the fibrous material to be bleached. Afterwards both ions are again united and
conveyed back into the electrolyzing apparatus.
Apparatus, which can be advantageously used in carrying this process into practice,
may be in the form of potcher engines. A modified form of the apparatus, giving
good results, is composed of vats each having three sides or concentric walls within
the innermost space of which the fibrous material to be bleached is continuously
whirled up by a screw-propeller so as to cause it to flow over the brim of the inner-
most lowest side of the vat into the adjacent annular space, whence it passes back into
the central space through openings formed in the bottom portion of the innermost
wall. Either ion enters the central space of the vat through a sieve or perforated
bottom and afterwards flows out through the finely perforated top portion of the
middle wall into the outer annular space, communicating with a tank, where both ions
again unite; the electrolyte thus recovered by the recombination of both ions is
again pumped into the electrolyzing apparatus. It is obvious that the fibrous material
may be caused to circulate through the said vats in the opposite direction to that
described, so as to rise within the annular space and sink within the innermost
space.
The drawings filed with my provisional specification represent bleaching apparatus
arranged in the manner just referred to.
Figs. 1 and 2 are a plan or top view and a sectional elevation respectively, of an
apparatus comprising two potcher-engines, so combined as to form one body;

page_text: Figs. 3 and 4 are similar views of an apparatus provided with two separate potcher-
engines.
Fig. 5 is a sectional elevation of the bleaching apparatus comprising vats each
having three sides or concentric walls.
As clearly shown in Fig. 1, the trough of the combined potcher-engines which are
used in this case, is divided by two incomplete longitudinal partitions a a into three
compartments viz., a central one band two lateral ones c c. Into the central com-
partment 6, the fibrous material made up with a suitable quantity of water to a kind
of pulp, is continuously fed by means of a screw conveyor pump d, and flowing down
along the inclined sieve or perforated bottom e it passes under the paddle wheelf by
which the material is pushed forward so as to cause it to enter the lateral compart-
ments cc; into one of these compartments the anion is conveyed through a perforated
tube g while a similar tube conveys the cathion into the other compartment. Flowing
down along the inclined bottoms of the compartments c, the material reaches the
outlet apertures e¹ c¹ provided at the lowermost points, and thence it is taken up by
the screw conveyor pump d, which again delivers the mass into the central com-
partment b. In this manner both ions are again united, and the regenerated
electrolyte is conveyed by a pump back into the electrolyzing apparatus j, in
which it passes through a sieve or perforated bottom 2 before coming in contact with
the electrodes, which are made of platinum, carbon or zinc. Between the top portions
of the successive anodes and cathodes are arranged incomplete cross partitions j³, and
the open bottomed cells which are thus formed by these incomplete cross partitions
alternately communicate with one and the other of two pipes ¹g extending along
the outside of the electrolyzing apparatus j. By this arrangement, one of the said
pipes g¹ will convey the anion to one of the perforated pipes 9 and the other pipe gl
will convey the cathion into the other perforated pipe g.
The apparatus represented by Figs. 3 and 4 differs from that just described, by its
comprising two separate potcher-engines k k. In either potcher-engine the fibrous
material to be bleached is caused to circulate by a suitably constructed cylinder k²,
and the washing drums k³ ³ cause the solutions of the anion and the cathion, which
are conveyed to the potcher-engines through the pipes 9 g, to enter the pipes 7, by
which they are again fed into the electrolyzer j. In this case, the direction of the
electric current is from time to time reversed in order to submit the fibrous material
to be bleached to the action of chlorine and alkali alternately.
This alternate reversal of the direction of the electric current must likewise take
place when bleaching is performed with the aid of the apparatus represented by
Fig. 5. In this apparatus, the material to be bleached is brought into the central
spaces of two vats m n o, m n o each having three sides or walls and by means of a
screw propeller p arranged at the centre of the bottom, the said material is caused to
rise in a continuous manner within the central space and afterwards to sink down
again within the annular space between the walls m and n, for re-entering the central
space through openings m¹ provided in the bottom portion of the wall m.
As already stated, the fibrous material to be bleached may with equal advantage
be caused to circulate in the reverse direction, so that it will continually pass
from the central space, through the openings m¹ and afterwards rise within the
annular space between the walls m and n, whence it passes over the top of m to flow
downward again.
The anion is supplied to the material under treatment, through the sieve-like or
-perforated-bottom, set-with-filter-stones, of the central-space-of-the-one-vat, while the
cathion is conveyed through the similar bottom of the central space of the other vat,
and-through-the-perforated-top-portion-n-of the middle walls of n, the said liquids
flow into the annular spaces between n and o. Thence both ions flow into a collecting
tank q, and the electrolyte thus partly recovered is pumped into the electrolyzer j of
the described arrangement.
Both vats are provided with covers o¹, hydraulically sealed at their rims, and
having outlet pipes o' for the gases evolved.

page_text: The apertures o³ provided with removable closures admit of the material under
treatment being inspected and samples withdrawn, while the steam pipes r afford
means for raising the temperature of the mass to the requisite point.
Instead of two vats such as described, two series of vats may be used in combination
with pipes for connecting the vats with each other in a manner similar to the
diffusers of diffusion batteries; in this case the process will be a continuous one.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The herein described process of bleaching vegetable fibres, by subjecting such
fibres to the action of chlorine or compounds containing active chlorine, and alkali
in an alternate manner as set forth.
2. The herein described process of bleaching vegetable fibres, by alternately con-
veying the ions produced by the electrolysis of a metallic chloride through a given
quantity of the said fibres as set forth.
3. In an apparatus for bleaching vegetable fibres, the combination with an
electrolyzing apparatus of two vessels containing the material to be bleached and
into either of which flows the anion while the cathion is caused to enter the other,
or two suitably connected series of such vessels, and means for reuniting the liquids
coming from the said two vessels or the last vessels of the two series and jointly
returning them into the electrolyzing apparatus as set forth.
4. In an apparatus for bleaching vegetable fibres, the combination with an
electrolyzing apparatus contained in a closed vessel, provided with inlet and outlet
pipes, of a potcher-engine, within the three parted trough of which the material
to be bleached travels over the sieve-like bottom of the central compartment and
passes partly into the right hand compartment and partly into the left hand com-
partment and thence is pumped back into the central compartment, pipes by which
the anion is conveyed into one lateral compartment and the cathion into the other
lateral compartment, and a pump by which the liquid passing through the said
sieve-like bottom is returned into the electrolyzing apparatus as set forth.
5. In an apparatus for bleaching vegetable fibres the combination with an
electrolyzing apparatus contained within a closed vessel provided with inlet and
outlet pipes, of two potcher-engines, into either of which flows the anion, while the
cathion is conveyed into the other, and from the washing drums of which these
liquids are returned into the electrolyzing apparatus as set forth.
6. In an apparatus for bleaching vegetables fibres, the combination with an
electrolyzing apparatus contained within a closed vessel provided with inlet and
outlet pipes, of two vats or two series of suitably connected vats, having three sides
or concentric walls, the central space of each vat wherein is arranged a screw
propeller, having a sieve-like bottom below which is located a chamber connected
with an admission pipe for either ion, while the middle wall is finely perforated at
its upper portion above the inner wall, and a pump the suction pipe of which
communicates with the outer annular spaces of the two vats, or of the last vats of
the two series, while its delivery pipe is connected to the electrolyzing apparatus
as set forth.
Dated this Fifth day of May 1890.
C. KELLNER,
Per L. W.