OR CONNECTED WITH THE OR TEXTILE MATERIALS OR " IMPROVEMENTS IN BLEACHING OF PAPER PULP OR OTHER FIBROUS FABRICS
Year: 1883

page_text: LETTERS PATENT to John Henry Johnson, of 47 Lincolns Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of
OR CONNECTED WITH THE
OR TEXTILE MATERIALS OR
"
IMPROVEMENTS IN
BLEACHING OF PAPER PULP OR OTHER FIBROUS
FABRICS "
communicated to him from Eugène
Hermite a person resident at Rouen in the Republic of France Chemist
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 30th October 1883.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gontleman "IMPROVEMENTS IN OR CONNECTED WITH THE BLEACHING OF PAPER
PULP OR OTHER FIBROUS OR TEXTILE MATERIALS OR FABRICS "
a communication
to me from Eugène Hermite a person resident at Rouen in the Republic of France
Chemist
This Invention relates to a process for bleaching textile materials generally but
is more especially applicable to bleaching paper pulp
In carrying out the first stage of the improved process chloride of sodium or of
potassium is decomposed by au electric current and in presence of a metal such as
lead, zinc, iron or tin (but preferably lead) in such a manner as to obtain caustic
soda and potash and a chloride of lead or other metal-This operation may be
conveniently performed by means of an apparatus arranged as hereinafter
described.
In a suitable vessel provided with a discharge pipe, is placed a hollow porous
cylinder in the centre of which is arranged a solid leaden cylinder forming a
negative electrode. A hollow leaden cylinder surrounding the porous cylinder
acts as the positive electrode any convenient number of cells thus constituted are
connected in tension Underneath the discharge pipes there is provided a gutter
or trough which collects the chloride of lead formed in the cells and conducts it to
a tank provided for its reception. A solution of say bay salt is prepared in another
tank and is transferred by a pump or otherwise to a store tank from which it is
distributed to the cells hereinbefore described.

page_text: The electric current acts upon the bay salt in the porous cylinder or vessel and
chloride of lead is formed at the positive pole and caustic soda at the negative pole
(or potash when chloride of potassium is used) The soda is removed by means of
pipes extending at one extremity nearly to the bottom of the porous vessels and
connected at the other extremity with a closed chamber from which the liquid is
drawn by a pump or otherwise and delivered into a suitable tank or vessel.
The soda or Potash obtained by this operation is used in the usual manner for
bleaching purposes and the chloride of lead serves to produce the chlorine necessary
for bleaching the materials prepared by the soda or potash.
In carrying out the second stage of the improved process the chloride of lead
obtained by means of the operation hereinbefore described is mixed with water
and a small quantity of hydrochloric acid and subjected to electrolysis in the
presence of the materials to be bleached
When applied to paper pulp the operation is preferably performed in the rag
engine which is arranged accordingly. The bottom of the trough of the engine is
nearly covered by a plate of lead laid in the trough and acting as a negative
electrodo upon which the precipitated lead is deposited. Over this is arranged an
insulated sheet of wire gauze. The positive pole situated above the gauze and
insulated therefrom is constituted by a plate of prepared carbon platinum or
platinised copper or other conducting material proof against the action of chlorine
At the negative pole any suitable conducting material may be employed in place
of the lead
The electric current causes nascent chlorine to be generated at the positive pole
and this chlorine is dissolved in the liquid and bleaches the materials under
treatment
At the negative pole is deposited metallic lead which may be used in decomposing
an alkaline chloride as herein before described
The gradual and regulated decomposition of the chloride of lead by the electric
current in the presence of the fibrous material enables the bleaching to be
economically effected without injuring the fibres
For decomposing the chlorides of potassium or of sodium, zinc iron or tin may
be employed in place of lead at the positive polo, caustic soda is thereby obtained
as in the first case and chlorides of zinc, iron or tin at the positive pole. The
chlorides subjected to electrolysis in presence of the textile or fibrous material
yield nascent chlorine and the metal is deposited as hereinbefore described with
reference to lead

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Patent Office on the 30th April
1884.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN OR CONNECTED WITH THE BLEACHING OF PAPER
PULP OR OTHER FIBROUS OR TEXTILE MATERIALS OR FABRICS a communication
to mo from Eugene Hermito a person resident at Rouen in the Republic of France
Chemist
This Invention relates to a process for bleaching textile materials generally but
is more especially applicable to bleaching paper pulp.
According to this Invention chloride of sodium or of potassium is decomposed
by an electric current and in the presence of a metal preferably lead or zinc in
such a manner as to obtain an alkali (caustic soda or potash) and a chloride of lead
zinc or other metal which is used for bleaching purposes by being subjected to
electrolysis in the presence of the material to be bleached as hereinafter described
And in Order that the said Invention may be fully understood I shall now.
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheets of drawings the same letters of reference
indicating corresponding parts in all the figures.
The operation of decomposing the chloride of sodium or potassium may be
conveniently performed by means of apparatus arranged as hereinafter described
and constitutes the first stage of the improved process. A series of suitable
troughs or vessels A figure 1 is provided made of wood or equivalent materials
each fitted with a discharge pipe a and containing hollow porous cylinders B in
the centres of which is arranged a solid cylinder C preferably of lead or zinc
forming a negative electrodo. Hollow cylinders D of the same metal surrounding
the porous cylinders B act as the positive electrodes. Any convenient number of
cells thus constituted are connected in tension as indicated in the drawing
Underneath the discharge pipes a there is provided a gutter or trough E which
collects the chloride of lead or zinc formed in the colls and conducts it to a tank F
provided for its reception-A solution of say bay salt is prepared in a tank H and
is transferred by a pump G or otherwise to a store tank K from which it is
distributed to the cells by suitable pipes not shewn in the drawing. The electric
current acts chiefly upon the solution contained in the porous cylinders or vessels B,
the solution occupying the remaining part of the cell A acting more especially as a
conducting liquid. Under the influence of the electric current chloride of lead or
zine is formed at the positive poles and caustic soda at the negative poles (or potash
when chloride of potassium is used)-The soda or potash is removed by means of
pipes b extending at one extremity nearly to the bottom of the porous vessels B
and connected at the other extremity with a closed chamber L from which the
liquid is drawn by a pump M or other suitable means and delivered into a tank or
vessel N.
The decomposing apparatus may also be arranged as illustrated in figures 2. 3
and 4, Figures 2 and 3 representing respectively a vertical section and a plan of
this apparatus and figure 4 is a detail hereinafter described.
According to this arrangement frames B of wood or metal to which are attached
on both sides sheets of vegetable parchment a secured in position by strips 6 of
wood are placed in a vessel A preferably about six feet deep five feet long and four
and a half feet wide.
One of the frames B is illustrated separately and in perspective in figure 4. The
negative electrodes slide freely in and are supported by grooves formed in the

page_text: sides of the frames B and are attached at their upper edges to iron bars c One
extremity of each of these bars c is supported by a copper or other suitable
conducting bar e and the opposite extremity is supported by a wood or insulating
bar f.
A series of (preferably five) such frames is placed in the vessel A as indicated
in the drawing, all the negativo electrodes being connected to the copper bar e and
arranged alternately with electrodes D of opposite polarity which are supported in
the vessel A and are connected in a similar manner to transverse bars c¹ supported
at one extremity upon a conducting or copper bar e¹ and at the opposite extremity
on an insulating or wood bar f¹.
Each frame thus constitutes a cell which is provided with a discharge cock or
pipe not indicated in the drawing. The soda or potash is formed in these cells as
in the apparatus hereinbefore described.
Any required number of troughs or vessels A may be connected in tension or in
derivation on the circuit of the generator, the dimensions of the troughs and the
number of the frames B in each trough being regulated according to the resistance
of the liquid and the tension of the current
The vegetable parchment forming the porous walls of the cells may be employed
in the form of thin sheets or in the form of thick sheets obtained by uniting several,
sheets in the process of conversion.
The soda or potash obtained as hereinbefore described is used in the usual
manner for bleaching operations and the chloride of lead or zinc produced at the
same time is utilised in order to produce chlorine.
In carrying out the second stage of the improved process the chloride of lead
or zinc obtained by means of the operation herein before described is mixed with
water and a small quantity of hydrochloric acid and subjected to electrolysis in the
presence of the material to be bleached such as paper pulp or other textile
materials or fabrics When applied to paper pulp the operation is preferably
performed in the trough of an apparatus arranged as hereinafter described and
illustrated in Figures 5 and 6 of the accompanying drawings, which represent a
vertical Section and a plan respectively of the said apparatus.
At the bottom of a trough A which as indicated in the drawing may also serve
as the trough of a machine for manufacturing paper pulp is placed a plate or Sheet a
of lead which entirely covers the said bottom and which is connected at its two
extremities with a copper bar or conductor b, in Electrical communication with the
negative pole of a short circuit commutator placed upon the conductors of the
dynamo or generator. Over this lead plate or sheet is placed a wood frame c
which extends all round the side of the trough A and supports either a Sheet of
wire gauze or preferably perforated plates d, of Earthenware.
A plate or slab e, of carbon or a carbonised cloth or a Sheet of platinum is placed
over this gauze or over the earthenware plates d, and communicates at the extorior
of the trough with a copper bar or conductor f which is connected to the positive
pole of the commutator and over this Carbon plate is placed a frame of wood c¹
supporting another wire cloth or perforated plates d'.
The paper pulp or textile materials are placed upon the last mentioned cloth or
plates and the vessel A is filled with water and chloride of lead zinc or other
inetal obtained as herein before described. Under the influence of the electric
current the chloride in the trough is decomposed, the metal passes to the lead
plate a or negative electrode and fills the space between this plate and the perforated
Earthon ware plates d, whilst the nascent chlorine disengaged in the trough A,
bleaches the contents.
On the conclusion of the operation, the metal is removed through an opening
provided for the purpose in the side of the trough and may be used again as
herein before described for decomposing a fresh supply of Chloride of Sodium or
otherwise.
It is obvious that other fibrous or textile materials or fabrics may be bleached
by being subjected to the same treatment in a suitable trough or vessel containing

page_text: the metallic chloride and provided with electrodes acting in a similar manner to.
the Electrodes hereinbefore described. Any suitable conducting material may be
substituted for the lead plate or Sheet a, hereinbefore described in connection with
the second stage of the process.
The bleaching process may also be conveniently performed in apparatus constructed.
as illustrated in figure 7. In this figure A is a Vessel or trough of wood metal or
masonry containing a solution of metallic chloride or chloride of Sodium and
provided at its lower part with an electrode b, connected to the negative pole of the
dynamo or generator. B is an inner vessel of wood metal or masonry, the bottom
of which is formed by a Sheet a of vegetable parchment above which is placed an
electrodo c, of carbon preferably in the form of a Carbonized Cloth or other material
proof against the action of the Chlorine and connected to the positive pole of the
dynamo or generator. This internal vessel B contains the paper pulp or textile
material to be bleached, the said pulp or materials being supported on a perforated.
earthenware plate d, and immersed in alkaline or acidulated water. The Vessels
A and B are provided with suitable discharge cocks as indicated in the drawing.
When applied to the bleaching of paper pulp the apparatus is provided with a
wheel carrying arms or blades and the other accessory appliances for preparing or
treating paper pulp. By the employment of this apparatus the materials to be
bleachod are preserved from contact with tho chloride.
When acidulated water is placed in the vessel B, chlorine or water impregnated
with chlorine is obtained and when alkaline water is employed an alkalino
hypochlorite is produced, Copper or zinc or other equivalent conducting matorial
may be employed at the negative pole. By these means Caustic Soda (or potash)
and a chloride are obtained. The Soda (or potash) is employed for preparing the
materials for the bleaching process. The gradual and regulated decomposition of
the chloride by an electric current in presence of the materials to be bleached
enables the bleaching to be effected in an economical manner and without
injuring the fibre.
According to another method of proceeding, acidulated water is placed in the
Vessels of an apparatus for decomposing the Solution of Chloride of Sodium.
The positive Electrode d, in the apparatus arranged as illustrated in Figure 8, is
formed by carbonised cloth or other material not liable to be attacked by the acids.
Soda is thus formed in the porous vessel B and chlorine water is obtained in the
external vessel A; a tube t, at the upper part of this vessel communicates with a
bleaching trough or troughs C, and a continuous circulation of the chlorine water
between this trough and the decomposing trough A is produced by the action of
a pump P.
In case it is desired to collect the gaseous chlorine a weak alkaline lyo is placed
in the porous vessel B, and brine is placed in the external vessel A provided with
a positive electrode. Soda is formed in the porous vessel and Chlorine is generated
at the positive polo. This chlorine may then be collected by any suitable means.
The gradual and regulated decomposition of the chloride by the electric current in
the presence of the pulp or fibrous material enables the bleaching to be oconomically
effected without injuring the fibres.
For decomposing the chlorides of potassium and Sodium, the metals zinc, iron or
tin may be employed in place of lead at the positive pole in the first stage of tho
process; caustic alkali is thereby obtained as in the operation herein before described
and chlorides of zinc, iron or tin at the positive pole. These chlorides subjected to
electrolysis in the presence of the paper pulp or textile or fibrous material yield
nascent chlorine and the metal is deposited as hereinbefore described with reference
to lead.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observo in conclusion that what I consider to be novel and original

page_text: and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patentis:-
1
First, In blenching paper pulp or other fibrous or textile materials or fabrics
decomposing chlorides of Sodium or potassium by an Electric current and in the
presence of a metal so as to obtain an alkali (Caustic Soda or potash) and a
metallic chloride for subsequent use in bleaching substantially as hereinbefore
described.
Second, In-bleaching paper pulp or other fibrous or textile materials or fabrics
decomposing a metallic chloride by electrolysis in the presence of the materials that
are to be bleached substantially as herein before described.
Third. A process of bleaching paper pulp wherein there are simultaneously
effected the electrolysis of the metallic chloride, the bleaching of the pulp and the
recovering the precipitated metal in a receptacle which also acts as the receptacle
of a machine for preparing the paper pulp substantially as herein before described.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this thirtieth day of April one thousand
eight hundred and eighty four.