Improvements in the Process of and Apparatus for Bleaching and Treating the Fibre of Peat or other Fibrous Substances.
Year: 1891

page_text: Date of Application, 1st Aug., 1891
Complete Specification Left, 2nd May, 1892-Accepted, 18th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Process of and Apparatus for Bleaching and
Treating the Fibre of Peat or other Fibrous Substances.
I, GUSTAVE ADOLPHE CANNOT, of Grove Park, in the County of Middlesex,
Merchant, do hereby declare the nature of this invention to be as follows:-
My present invention relates more especially to the treatment of peat fibre for
the purpose of bleaching it so that it can be used for making into threads by the
machinery ordinarily used for such purpose, or so that it can be used for the purpose
of making pulp for the manufacture of paper, and it has for its objects novel
methods of so treating the peat, and of construction and arrangement of the apparatus
and appliance necessary for such treatment, such apparatus and appliances being
also applicable to the treatment of other fibrous materials such as jute, hemp, flax,
cotton, as well as peat.
For the successful treatment of such fibrous materials by the means described,
it is essential that the apparatus for washing and treating them, for preparing and
mixing the necessary gases which I use, for submitting the mixed gases to the
action of electricity, and for preparing from them a solution in which the fibrous
material is treated, should be simple, easily, and quickly worked, inexpensive and
safe, and effective for the required purpose, and the object of my present invention
is to attain these objects in the manner hereinafter described.
In the processes of bleaching peat fibre hitherto used, chlorine gas, sulphurous
acid, and electricity, together with oxygenated water, have been employed, but the
result has been imperfect as the bleaching does not reach the centre of the fibres,
and the continued action of the air reoxidizes the bases left in the fibre and
discolouration takes place.
It is therefore necessary, first, to bleach the fibres to their centre, and, second,
to destroy at the same time the oxidizable bases the presence of which would lead
to the subsequent discolouration of the fibres.
Chlorine gas is the most suitable substance to obtain the first result, but to
secure the second it is necessary so to modify it that the gas should be itself
oxidized at the moment of its formation in order to give it greater power of
penetration, and moreover that the oxidizing agent should itself have bleaching
properties whilst having no subsequent injurious action on the fibres.
For this purpose, are necessary the simultaneous contact of the nascent chlorine
with oxygen in the presence of an electric current, and by my invention I obtain a
highly concentrated solution of such hypo-chlorous acid by simple means and with
inexpensive apparatus.
Hypochlorous acid has a bleaching power three or four times greater than
chlorine, but it is a dangerous substance being liable to spontaneous detonation
producing violent explosion, for which reason, as well as from its cost, it has not
come into use.
By my improved process and the apparatus hereinafter described, I obtain an
abundant supply of hypochlorous gas at little cost, stable, and without danger.
The entire process is as follows
--
Oxygen and chlorine gases are simultaneously produced in separate generators
and are combined in their nascent state before coming in contact with the material
to be treated.
The gases on leaving the generators are allowed to bubble up the chlorine
through a solution of chloride of sodium and the oxygen through pure water, and
they then pass through a washing vessel where they leave any remaining impurities,

page_text: after which they pass into a receiving vessel where they are dried and mixed, and
they then pass together into another apparatus sufficiently cooled by a current of
cold water in which they are subjected to the action of a series of electric sparks.
The gases combine in this receiver, that is to say the chlorine attaining its
maximum of oxidation passes into the state of hypochlorous acid, which being
unstable and dangerous in a free state is passed by degrees as it is produced into an
alkaline solution such as caustic soda or potash by which it is absorbed. This
solution is allowed to attain a strength of about 25 Baumè with a density of 1.23,
in which state it is too strong for use, and a small quantity of it is diluted with
sufficient water and it is then ready for bleaching the peat fibre, in the following
way.
The fibre is boiled in a vessel of the kind hereinafter described, under a
pressure of about one atmosphere in water containing about three per cent. of an
alkali such as carbonate of soda, and is then washed.
The water, still hot but highly coloured, may be again used in a second boiler,
and again in a third, increasing the pressure somewhat in each succeeding one and
lengthening by a quarter of an hour the time of boiling, a little additional alkali
being added.
The resulting liquids contain nearly all the soluble matters contained in the peat
fibre, and may be cooled and evaporated in pans and the soda or other alkali
recovered. The peat does not require drying before treatment, nor is the washing
absolutely necessary, unless very pure and colourless fibre is required.
An alkaline solution of 2% (or Baumè) of caustic soda or potash is then
introduced into the boiler, and the fibre is boiled in it for about one hour under
very low pressure. The water is then drawn off and may be re-used or the alkali
recovered, and a fresh similar solution is introduced in which the fibre is boiled
again for four or five hours according to the colour which the water takes, the
operation being completed by an active boiling at a pressure of 1 to 15 atmospheres
for half an hour. The fibre is then removed to washing vessels in the first of
which it is actively agitated for a short time, and the water which becomes
charged with colouring matter is added to that used in the first boiler.
The peat fibre is then washed in suitable washing machine until the water runs
off clear, and it is then placed in a vessel containing water acidulated with 2% of
hydrochloric acid, where it remains for about 6 hours, being occasionally stirred to
ensure all its parts being equally treated.
The water need not be thrown away but can be used until it only slightly
affects litmus, and the salts which it contains can be afterwards recovered if
desired.
The fibre is then thoroughly washed until it is perfectly neutral, and is then
immersed in a bath of hypochlorous solution containing 0.5 to 5% of active
hypochlorous gas, according to the purpose for which it is to be used. The peat
fibre being constantly agitated in this bath are rapidly bleached, but to attain the
best result it is advisable to use a weak solution constantly renewed, as in this
way the fibres are more uniformly bleached and are absolutely unattacked.
Careful and prolonged washings follow the bleaching.
The washings are continued until no smell is perceptible and the water remains
absolutely neutral, which may require about two days if the supply of water is
limited. These gentle but prolonged treatments are especially advisable where the
peat fibre is intended for making into thread, as it is not at all weakened. For
paper pulp the treatment may be more active and quicker. I will now proceed to
describe the apparatus and appliances which I use.
Supposing that the invention is to be applied to the treatment of fibrous peat
for making paper pulp, or other purposes, the peat is submitted to the action of
the first bath of hot water containing a small proportion of alkali, in a vessel of
metal or other material of sufficient strength, cylindrical in shape with a convex
bottom, the cylinder being carried in a vertical position by two trunnions some-
what above its centre of gravity, supported in suitable fixed bearings.

page_text: The cylinder therefore remains in a vertical position, but can be readily
inclined more or less if desired.
In the lower part of the vessel is arranged close to its sides a coil of pipe, into
which steam can be admitted through a valve at its upper end, a valve or cock
being also provided at its lower end for drawing off any condensed water, and
another cock or valve communicating with a pipe through which the steam passes
off, either to similar vessels, or to the gas generator, hereinafter described. An
agitator is fixed in the centre of the vessel, consisting of a vertical shaft revolving
in a footstep at its lower end, whilst its upper end turns in a bearing in a cross
bar or frame which also carries a horizontal shaft passing out through a stuffing
box in the side of the vessel, and driving the vertical shaft by bevelled toothed
wheels, whilst it is itself driven by a pulley and belt by steam or other power.
The lower part of the shaft is fitted with bars or plates arranged helically but
in opposite directions, so that the materials in the vessel are stirred without any
uniform rotary movement being imparted to them.
A. thermometer is contained in an external tube connected with the inside of
the vessel in a suitable position, and having a strong glass inserted in its side
through which the thermometer indications can be read. A pressure gauge is
arranged communicating with the upper part of the vessel. The upper end of the
vessel is closed by a strong separate domed or arched cover, which is suspended
by chains connected to a winch, in such manner that it can be readily raised or
lowered as required. This cover is fitted with a safety valve, and a whistle giving
an alarm at a predetermined pressure, and also with a vacuum valve opening
inwards. At the bottom of the vessel is a cock communicating with three pipes
each provided also with a cock by which the liquid in the vessel can be drawn off,
and conducted away to regenerating or concentrating vessels as may be required.
In the upper part of the vessel is arranged a pipe terminating in a
having an external cock by which water can be admitted for washing the vessel or
its contents, such water being drawn off through another cock at the bottom.
These arrangements are necessary, in order to prevent the injury which would
result to the peat fibre from the simultaneous contact of air and hot alkalies.
rose and
The cover is fixed by a sufficient number of bolts and nuts. The lower side of
the flange of the cover has a projecting rib which enters a corresponding groove
in the flange of the vessel, which contains a layer of asbestos packing by which
a tight joint can be made under any pressure or temperature.
Where a large
quantity of material is to be treated, I prefer to use two or more of the vessels
described of moderate size, instead of one inconveniently large one, and one man
alone can then attend to five or six of them.
In order to produce the chlorine gas, which is required for the subsequent
treatment of the fibrous material, I prefer to make use of the action of hydrochloric
acid upon peroxide of manganese, in the following apparatus.
I take a leaden vessel or a vessel lined with lead of ovoid form, its largest part
being below and being surrounded by an iron jacket into which the steam which
leaves the boiler already described can be admitted through a pipe provided_with
a valve or valves, and can pass away through another pipe to a second gas
generator, the jacket forming a heating chamber.
A cock for drawing off condensed water from the jacket is also provided, and
another cock or valve for emptying the vessel, which is supported on a masonry
foundation. An agitator upon a vertical spindle is arranged in the vessel, and is
turned when required by a cross handle upon its upper end after it has passed
through a stuffing box or water seal. The vessel is filled with peroxide of
manganese to a sufficient height and the acid is admitted as required until at the
end of the operation it about half fills the vessel. The acid is introduced through
a funnel having a coiled stem, the liquid in which serves as a seal, and also acts as
a safety valve in case of too great or too little pressure. An opening and cover
are also provided for the introduction of the manganese, and another opening and

page_text: pipe for conveying away the gas, both openings being provided with water sealed
joints.
The gas thus obtained passes to the washing apparatus, consisting of a large
stoneware vessel or carboy, glazed inside and having three openings at its top, one
of which remains closed with a stopper when the vessel is being used, whilst the
tube from the gas generator last. described passes down through one of the other
openings nearly to the bottom of the vessel, which is partly filled with a solution
of chloride of sodium, through which the gas rises in bubbles, leaving a little
hydrochloric acid and other impurities in the liquid, first driving out the air in the
vessel, and escaping through another pipe in the third opening above.
The vessel is cleaned when necessary by a jet of water through the central
opening, and it can be emptied by a cock at the bottom.
The oxygen gas required is produced in a similar jacketed vessel to that in which
the chlorine is produced and in a somewhat similar way, by the action of sulphuric
acid upon peroxide of manganese. The bottom of the vessel is covered with pieces
of manganese as large as peas. and sulphuric acid is added gradually. As with the
chlorine, the production of the gas commences without heat, which is applied later,
and it is made to bubble up in a vessel exactly similar in form and arrangement to
that described for the chlorine, but containing plain water.
Great advantages and economy result from the use of apparatus of the same kind
and operating in the same way, with nearly the same materials, for both gases.
When, in time, a sufficient quantity of the sulphites and chlorides of manganese
have accumulated, they may be restored to their original condition in the ordinary
well known way, and re-used.
The chlorine and oxygen gases, after leaving the washing vessels last described,
pass separately to a drying apparatus common to both, where they are dried and
Inixed together.
This apparatus consists of a rectangular box, lined with glass, and having at its
opposite sides and above, windows of transparent glass through which its interior
can be observed.
The drying device consists of a horizontal plate of glass or porous porcelain,
pierced with numerous holes, and situated about half way up in the box. Upon this
partition are placed fragments of pumice stone impregnated with sulphuric acid,
or of chloride of calcium or other desiccating material. The chlorine gas is
admitted through an opening in the end of the box above the partition,
and the oxygen gas through a similar opening below the partition, and the
former gas being the heavier tends to pass down through the perforations whilst
the oxygen gas tends to rise up through them. As fresh bubbles of both gases
are constantly arriving, they become mixed together and dried, and are driven
forward to an exit opening at the other end of the box opposite the end of the
partition, a pipe from which conveys the mixed gases to the oxidizing apparatus,
the object of which is to render the oxidation of the chlorine much more
energetic, by the presence of ozone, thus obtaining considerable advantage in
which however the liability to dangerous explosives has to be guarded against.
To avoid such explosions, or to render them harmless if in spite of precautions
they should occur, a small and thin glass tube is arranged horizontally, through
the centre of which passes a wire of copper coated with silver, gold, or preferably
platinum. This wire ends at a short distance from one end of the tube, its other
end being connected to one of the poles of an electrical induction apparatus.
Outside the tube is coiled helically a similar wire, which also ends a short
distance from the end of the tube, its other end being connected to the other
pole of the induction coil. When the latter is in operation, the electrical circuit
can only be completed between the wires, through the glass of the tube, and a
rapid series of sparks pass accordingly. The glass tube described is contained
in a second glass tube of larger diameter in which it is held centrally by a
sufficient number of small glass balls or supports, and the mixed gases are

page_text: introduced into one end of the two tubes, and the rapid series of sparks passing
through them causes them to actively combine together in the required pro-
portions.
The oxidation of the chlorine is in this way quickly and effectively produced, but
in order to guard against danger from explosions which are liable to take place
when the temperature rises above 15° to 18° centigrade, the tubes containing the
gases are insulated in a porcelain tube glazed inside, which is itself contained in an
outer case of thin metal through which a constant current of cold water is passed, its
passage being regulated by cocks, or other refrigerating means may be used.
The induction coil is provided with a commutator, and is set in operation by a
dynamo of sufficient force actuated by steam or other suitable power. By means of
the commutator the current may be reversed or diminished when desired.
Instead of glass tubes provided with wires as described, a central cylinder or
pencil, of carbon may be used connected with one pole of the induction coil, and
arranged in but insulated from a carbon tube connected with the other pole, so that
sparks pass between them. The gases pass through the carbon tube which is kept
cool in the way already described.
The combined gas (hypochlorous gas) is conveyed away through a pipe provided
with a cock or valve, and by a moveable coupling and pipe to the bottom of a vessel
or carboy containing water in which it is entirely dissolved.
The liquid scarcely fills two thirds of the carboy when the operation commences,
but when it is saturated with gas it fills the latter. At this moment a workman
releases the coupling tube, and as quickly as possible removes the full carboy, and
substitutes a fresh one upon which he replaces the coupling.
There is always however a slight escape of gas, and as it is very injurious to
breathe, it is preferable to arrange a hood connected with a sufficiently powerful
draught, above the receiving vessel.
Fresh carboys are substituted one after another until the whole of the
disengaged gas has been absorbed, and in calculating the quantity, quality, baro-
metric pressure, and the temperature of the solution, should be considered.
By means of the apparatus described the quality of the bleaching material for
any weight of peat or other fibre can be very quickly and readily made, and the
solution of hypochlorous acid well stoppered and kept in the dark retains its
properties for a very long time.
In cases where it is required to treat large quantities of gases with electricity, it
is preferable to use the following modified apparatus, instead of that described (in
which it might be difficult to obtain glass which would allow the passage of the sparks
without perforating the glass).
This consists of a rectangular box lined with glass, and with an opening for the
admission of the gases at one end and for the escape at the other end.
The top of the box is fitted inside with a series of insulated parallel plates of gas
carbon descending nearly to the bottom of the box. All these carbons are connected
to the positive pole of the induction coil. Upon the bottom of the box similar plates
are arranged rising between the others, and to them is connected the negative pole
of the coil. The gases have to pass up and down between the plates and are entirely
This
oxidized when they leave the box by the electricity passing through them.
apparatus is, like the former one, kept cool by a continuous current of cold water,
and it may be moreover enclosed in a larger box or case containing fine sand, in
order to render harmless any explosions which, in spite of precaution, may occur.
The vessel or basin in which the bleaching is effected, is of a shape nearly
elliptical in plan, and is provided with a central vertical partition reaching nearly to
the ends of its larger axis, so as to form an endless channel. On one side of this
channel a float wheel of suitable shape is arranged, driven by suitable power so that
it causes a constant circulation of the liquid in the channel. The parts of the
materials to be bleached are thus rolled over and over each other, so as to con-
stantly present fresh surfaces to the liquid. When sufficiently bleached in this
apparatus the peat or other material is washed and dried in a machine consisting of

page_text: a vertical cylindrical vessel of cast iron or other suitable material, fitted at its upper
part with bearings in which revolves the upper end of a central vertical shaft,
and also a horizontal driving shaft, set in motion by steam or other power and
driving the vertical shaft by properly proportioned friction cones.
The lower end of the vertical shaft turns in a footstep at the bottom of the vessel,
which bottom is made inclined so that the water collecting on it runs off through a
lateral opening and spout.
The vertical shaft carries a strong circular frame at its lower end, upon the outer
edge of which is fixed a strong vertical cylinder preferably of iron perforated with
holes of considerable size over its entire surface, and inside this cylinder is fitted a
corresponding one of wire gauze by which small pieces of the material are prevented
from passing away with the water through the large holes.
The upper end of the revolving perforated cylinder is closed by an annular cover,
convex in section, which prevents the contents of the cylinder from being thrown
out. A water jet, provided with a rose at its end, facilitates the washing of the
material, and is used by a workman standing upon steps on the side of the outer
vessel.
A strong door is made at one side through the perforated cylinder and wire
gauze, for introducing and removing the materials treated, a corresponding door
being also made in the outer vessel.
When the pulp for paper or other fibrous material has been so thoroughly
washed, that all smell is removed, it is dried by the rapid revolution of the cylinder,
to the degree required, and in the manufacture of paper the material may be
removed and packed for carriage or introduced directly into the paper making vat.
Except for the boilers first described in which steam at some pressure is used,
little power is required.
Dated this 1st day of August 1891.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Process of and Apparatus for: Bleaching and
Treating the Fibre of Peat or other Fibrous Substances.
I, GUSTAVE ADOLPHE CANNOT, of Grove Park, in the County of Middlesex,
Merchant, 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, and accompanying drawings, that is to say :-
My present invention relates more especially to the treatment of peat and peat
fibre for the purpose of bleaching it so that it can be used for making into thread
by the machinery ordinarily used for such purpose, or so that it can be used for
making pulp for the manufacture of paper and other purposes.
It has for its object
novel methods of treating the peat fibre (and of constructing and arranging the
apparatus and appliances necessary for such treatment) or for the treatment of other
fibre, such as peat jute, hemp, flax, or cotton.
The bleaching process depends upon the action of different substances each having
decolourizing properties, but the combined action of which is necessary to bleach
peat fibre without breaking the weak filaments of cellulose of which it is formed.
For the successful treatment of the fibrous materials by the means hereinafter
described, it is essential that the apparatus for washing and treating them, for
preparing and mixing the gases which I use, for submitting the mixed gases to the
action of electricity, and for preparing from them a solution in which the fibre is
treated, should be simple, easily and quickly worked, inexpensive and safe, and
effective for the required purposes, and the object of my present invention is to attain
these results in the manner described and shewn.
In the process of bleaching peat fibre hitherto used, chlorine gas, sulphurous acid,

page_text: and electricity, together with oxygenated water, have been employed, but the
result has been imperfect as the bleaching action does not reach the centre of the
fibres, and the continued action of the air reoxidizes the bases left in the latter, and
discolouration again takes place.
It is therefore necessary; first, to bleach the fibres to their centre, and second,
to destroy at the same time the oxidizable bases the presence of which would lead
to the subsequent discolouration of the fibre.
Chlorine gas being cheap and easily obtained, is the most suitable substance to
obtain the first result, but to secure the second it is necessary so to modify it that
it shall become itself oxidized at the moment of its formation in order to give it
greater power of penetration, and moreover that the oxidizing agent shall itself
have bleaching properties whilst without injurious action upon the fibre.
For this purpose are necessary the simultaneous contact of the nascent chlorine
with oxygen, and the presence of an electric current, and by my invention I obtain
a highly concentrated solution of hypochlorous acid (the bleaching substance
required) by simple means and with inexpensive apparatus.
Hypochlorous acid has a bieaching power three or four times as great as chlorine,
but it is a dangerous substance to use, being liable to spontaneous detonation
producing violent explosions, for which reason, as well as from its cost, it has not
come into use.
By my improved process and apparatus I obtain an abundant supply of hypo-
chlorous acid gas at little cost, stable, and without danger.
The entire process is as follows:-
Oxygen and chlorine gases are simultaneously produced in separate generators
and are combined in their nascent state. The chlorine gas on leaving its generator
is allowed to bubble up through a solution of chloride of sodium, and the oxygen
gas through plain water, contained in suitable vessels, and from thence they pass
through washing vessels where they leave any remaining impurities, and into a
receiver where they are dried and mixed, and from which they pass together into
an apparatus kept cool by a current of cold water, in which they are submitted to
the action of a stream of electric sparks. The gases combine in this apparatus,
that is to say the chlorine attaining its maximum of oxidation passes into the
state of hypochlorous acid, which being unstable and dangerous in a free state is
passed into an alkaline solution such as caustic soda or potash, by which it is
absorbed. This solution is allowed to attain a strength of about 25° Baumè with
a density of 1.23, in which state it is too strong for use and a small quantity of it is
accordingly diluted with sufficient water and it is then used for bleaching the peat
or other fibre by means of the apparatus hereinafter described and illustrated in
Figures 1, 4, and 5, of the accompanying drawings, which are in illustration of the
invention.
Figure 6 is a general view of the apparatus by which I obtain the solution of
hypochlorous acid gas as just described, Figure 2 is a section on a larger scale of
the vessel for drying and mixing the gases, and Figure 3 of the apparatus in which
the gases are combined in the presence of electric sparks.
In Figure 6 a is the vessel of lead, or lined with lead, in which the oxygen gas is
produced, preferably by the action of sulphuric acid upon peroxide of manganese.
The vessel is of ovoid form and is surrounded by an iron jacket into which
steam can be admitted through a pipe e provided with a valve, and pass away
through another pipe, the jacket & forming a heating chamber which can be heated
when required. A cock is provided for drawing off condensed water from the
jacket, and a cock or valve e for emptying the vessel. An agitator upon a vertical
spindle is arranged in the vessel a and after passing through a stuffing box or
water seal at g, is provided with a cross handle by which the agitator in the vessel
can be turned.
The vessel a is filled to a sufficient height with peroxide of manganese in pieces
as large as peas and the sulphuric acid is admitted gradually until at the end of the
operation it about half fills the vessel. The acid is introduced through a funnel h
"

page_text: having a coiled stem, the liquid in which serves as a seal and also acts as a safety
valve in case of too great or too little pressure. An opening and cover i are also
provided for the introduction of the manganese, and another opening and pipe k for
conveying away the gas, both openings being provided with watersealed joints.
The gas thus produced passes to a washing vessel 1, consisting of a large stoneware
vessel or carboy, glazed inside, and having three openings m, n, o, at its top, one of
which n remains closed by a stopper when the vessel is being used, whilst the pipe k
passes down through the opening m nearly to the bottom of the vessel which is
partly filled with water through which the gas rises in bubbles leaving any
impurities in the water, and escaping (after first driving out the air in the vessel)
through the opening o and pipe p. The vessel a is cleaned when necessary by a
jet of water through the opening n, and it can be emptied through a cock rat the
bottom.
The chlorine gas is produced in a similar jacketed vessel a', and in a somewhat
similar way to the oxygen by the action of hydrochloric acid upon peroxide of
manganese. The vessel a' is filled to a sufficient height with the manganese and
hydrochloric acid is added gradually until at the end of the operation it about half
fills the vessel.
As with the oxygen, the production of the chlorine commences without heat,
which is applied later when required, and the gas is made to bubble up in a vessel
or carboy exactly similar to 1, partly filled with a solution of chloride of sodium
through which the gas rises in bubbles leaving a little hydrochloric acid or other
impurities in the liquid. Considerable advantage, economy, and simplicity result
from the use of apparatus of the same kind and operating in the same way with
nearly the same materials, for both gases.
In obtaining the oxygen in the way described, about half the quantity contained in
the peroxide is given out 100 kilogrammes of peroxide containing 36.64 kilogrammes
of oxygen, of which 18.32 are obtained in a gaseous state, having a volume of
12,000 litres at a pressure of 0.760, a quantity sufficient for the treatment of about
17,500 kilogrammes of peat.
When in time a sufficient quantity of the sulphates and chlorides of manganese
have accumulated in the vessels, they may be restored to their original condition in
the ordinary well known way and re-used.
The chlorine and oxygen gases, after leaving the washing vessels 11, 1 respectively,
pass separately to a drying apparatus common to both, shewn at s in Figure 6 and
on a larger scale in Figure 2, where they are dried and mixed together. This
apparatus consists of a rectangular box lined with glass and having at its opposite
sides and top windows of transparent glass through which its interior can be
observed. The drying device consists of a horizontal plate G, G₁, of glass or
porous porcelain, pierced with numerous holes.
Upon the partition are placed numerous fragments of pumice stone impregnated
with sulphuric acid or of chloride of calcium or other desiccating material. The
chlorine gas is admitted through A and has a specific gravity of 1.33 whilst the
oxygen admitted through B has a specific gravity of 1.05, so that the former has a
tendency to pass down through the perforations, whilst the latter tends to rise up
through them. As fresh bubbles of both gases are constantly arriving they become
mixed together and dried, and pass forward and out through a pipe D at the other
end of the box, through which they pass to the oxidizing apparatus & Figure 6,
shewn on a larger scale in Figure 3, the object of which is to render the oxidation
of the chlorine much more energetic, by the presence of ozone in the air, thus
obtaining considerable advantage, in which however the liability to dangerous
explosions has to be guarded against. To avoid such explosions, or to render them
harmless if, in spite of precautions they should occur, a glass tube C, C₁, C
(Figure 3) about 0.008 m. diameter and 0.002 m. thick, and about 1.50 long, is
arranged horizontally, through the centre of which passes a copper wire B, coated
with silver, gold, or preferably platinum.
This wire ends at a short distance (about 0.05 m.) from the outer end of the

page_text: tube c, its other end B being connected to one of the poles of an electrical
induction coil J. Outside the tube c, c', c¹¹, is coiled helically a similar wire C,
which ends at a short distance from the inner end of the tube, its other end being
connected to the other pole of the induction coil J. The tube which carries the
wires is inserted into a larger glass tube D, in the axis of which it is supported by
small glass balls or supports. The mixed gases pass through these tubes from the
mixing apparatus already described and a stream of electric sparks which pass
between the wires from the induction coil, and through the inner glass tube cause the
gases to combine rapidly together in the required proportions to form hypochlorous
acid gas.
The oxidation of the chlorine is in this way very quickly and effectively produced,
but in order to guard against danger from explosions which are liable to occur
when the temperature rises above 15° to 18° C. The tubes containing the gases
are insulated in a porcelain tube E glazed inside which is itself contained in an
outer case of thin metal F, through which a constant current of cold water is made
to circulate from a cock V through a funnel S, passing out through the pipe H and
cock U.
The induction coil J is connected with a commutator I, and is set in operation
by a dynamo K, of sufficient power and of any suitable kind driven by a belt T.
Instead of glass tubes and wires as described and shewn, a central cylinder or
pencil of carbon may be used connected with one pole of the induction coil, and
arranged in-but insulated from-a carbon tube connected with the other pole so
that the sparks pass between them. The gases pass through the carbon tube, which
is kept cool in the way already described.
The combined gas (hypochlorous acid gas) is conveyed away through a pipe
provided with a cock or valve M, and through a moveable coupling tube R to a
pipe O which descends nearly to the bottom of a vessel N containing a solution of
caustic soda or potash in which it is entirely dissolved.
The liquid scarcely fills two thirds of the vessel N when the operation commences,
but when it is saturated with gas it fills the latter to the neck. At this moment a
workman closes the cock M, releases the coupling tube R, and as quickly as
possible removes the full carboy and substitutes à fresh one, upon which he replaces
the coupling tube, and reopens the cock M. There is always however a slight
escape of gas and as this is very injurious to breathe it is preferable to arrange a
hood (as shewn in Figure 6) connected with a sufficiently powerful draught, above
the receiving vessel or carboy N.
.
Fresh carboys are substituted one after the other until the whole of the
disengaged gas has been absorbed, and in calculating the quantity, barometric
pressure and the temperature of the solution, should be considered.
By means of the apparatus described the quantity of the bleaching material for
any weight of peat or other fibre can be very quickly and cheaply made and the
solution of hypochlorous acid, well stoppered and kept in the dark retains its
properties for a very long time.
Where fibrous peat is to be bleached by a solution of hypochlorous acid for
making paper pulp or other purposes, the peat is submitted in the first place to the
action of a bath of hot water containing a small proportion of alkali, in a strong
vessel of the kind illustrated in Figure 1, which shews a vertical section through
it. It consists of a large cylindrical vessel, of metal or other material of sufficient
strength and having a convex bottom. It is supported in a vertical position by two
trunnions A, A', somewhat above its centre of gravity, turning in fixed bearings V, VI,
so that it ordinarily retains its vertical position, but can be readily inclined more
or less if required, for repairs or other purposes.
In the lower part of the vessel is arranged a coil of pipe B, into which steam can
be admitted through a valve or cock C, a similar cock D being also provided for
drawing off the condensed water and another cock or valve communicating with a
pipe H through which the steam passes off, either to similar vessels, or to the jackets
of the gas generators already described, and shewn in Figure 6.
12

page_text: An agitator E is fixed in the centre of the vessel upon a vertical shaft, revolving
in a footstep at its lower end whilst its upper end turns in a bearing in a cross bar
or frame, which also carries a horizontal shaft passing out through a stuffing box in
the side of the vessel, and driving the vertical shaft by bevelled toothed wheels F,
whilst it is itself driven by a pulley and belt G. The agitator E consists of bars
or plates arranged helically but in opposite directions, so that the materials in the
vessel are stirred without any uniform rotary movement being imparted to them.
A thermometer is contained in an external tube at I, connected with the inside of
the vessel and having a strong glass inserted in its side through which the indica-
tions of the thermometer can be read.
A gauge glass is shewn at J and a pressure gauge communicating with the upper
part of the vessel, at K.
The upper end of the vessel is closed by a strong separate domed cover M, fitted
with a safety valve L, and whistle giving an alarm at a predetermined pressure, and
also with a vacuum valve N opening inwards. It is suspended by three chains to a
hook at upon a chain passing round pullies Z, Z', to a winch W, by which the
cover can be readily raised or lowered as required. At the bottom of the vessel is
a cock O communicating with three distributing pipes provided with cocks P, Q,
and R, by which the liquid can be drawn off and conducted to regenerating or
concentrating vessels as may be desired. At S is arranged a pipe terminating in a
rose and having an external cock, by which water can be admitted for washing the
vessel or its contents, such water being drawn off through the cock T, without
raising the cover M. These arrangements are necessary to prevent the injury which
would result to the peat fibre from the simultaneous contact of air and hot alkalies.
The cover is firmly fixed by a sufficient number of bolts and nuts a, a, and the
lower side of its flange has a projecting rib which enters a corresponding groove
into the flange of the vessel which contains a layer of asbestos packing by which a
tight joint can be made at any pressure or temperature.
Where a large quantity of material is to be treated I prefer to use two or more
of the vessels described of moderate capacity, instead of one inconveniently large
one, and one man can then attend to five or six of them.
The peat fibre is boiled for a sufficient time (about one hour) in a vessel of the
kind just described, under a pressure of about one atmosphere, in water containing
about three per cent. of alkali such as carbonate of soda, and is then washed. The
water still hot but slightly coloured may be again used in a second boiler, and again
in a third, the pressure being somewhat increased in each succeeding one and the
time of boiling being somewhat lengthened, whilst a little additional alkali is also
added.
The resulting liquid contains nearly all the soluble matters contained in the
peat fibre, and may be evaporated in pans and the soda or other alkali recovered.
The peat does not require drying, nor is the washing absolutely necessary unless
very pure and colourless fibre is required.
An alkaline solution, of 24% (or 1° Baumè) of caustic soda or potash, is then
introduced into the boiler, and the fibre is boiled in it for about one hour under very
low pressure. The water is then drawn off and may be re-used or the alkali
recovered, and a fresh similar solution is introduced in which the fibre is boiled
again for four or five hours, according to the colour which the water takes, the
operation being completed by an active boiling for half an hour at an increased
pressure. The fibre is then removed to washing vessels, in the first of which it is
actively agitated for a short time, and the water which becomes charged with peaty
products is added to that used in the first boiler.
The peat fibre is then washed for a considerable time in washing machines of any
suitable kind, until the water runs off clear, and it is then placed in a vessel
containing water acidulated with about 2% of hydrochloric acid, where it remains
for about six hours, being occasionally stirred to ensure all its parts being equally
acted on.
This water need not be thrown away but can be used until it only slightly

page_text: affects litmus, and the salts which it contains can be afterwards recovered if
desired.
The fibre is then thoroughly washed until it is perfectly neutral, and is then
immersed in a bath of the hypochlorous acid solution containing 0.5 to 5% of
active hypochlorous acid gas, according to the purpose for which the fibre is to be
used.
The bath which I prefer to use is illustrated in plan in Figure 5, and consists of
a vessel 1 nearly elliptical in plan, provided with a central vertical partition 2
reaching nearly to its ends, so as to form an endless channel. On one side of the
channel a paddle wheel 3 is arranged, driven by suitable power so that it causes a
constant circulation of the liquid in the direction of the arrows. The parts of the
material to be bleached are thus rolled over and over each other, so as constantly to
present fresh surfaces to the liquid.
The fibres being constantly agitated in the bath are rapidly bleached, but to
attain the best result it is advisable to use a weak solution constantly renewed, as
in this way the fibres are more uniformly bleached and are absolutely unaffected by
the liquid. Careful and prolonged washings follow and are continued until no smell
is perceptible and the water remains absolutely neutral, which may require about
two days if the supply of water is limited. These gentle but prolonged treatments
are especially advisable where the fibre is intended for making thread, as it is not
at all weakened thereby. For paper pulp the treatment may be more active and
quicker.
A
These washings may be effected in any suitable vessels but I prefer to use
apparatus of the kind illustrated in Figure 4, which shews a vertical section through
the machine. A is a friction cone of considerable diameter fixed upon an adjustable
shaft turning in bearings C, C', provided with fast and loose pulleys, the cone A
driving the smaller cone B upon the upper end of the vertical shaft F, the lower
end of which turns in the footstep N at the bottom of the vertical cylinder L.
cylinder of wire gauze G is carried by a frame upon the shaft F and keeps back
small fragments which might pass through the perforation in an outer cylinder I,
which is closed by an annular cover J convex in section as shewn which prevents
the contents of the cylinder from being thrown out. A water jet K, provided with
a rose at its end, facilitates the thorough washing of the materials, and is manipulated
by a workman standing upon steps M, M¹, on the side of the vessel.
A strong door is shewn at H, through which the material treated is introduced
and removed, a corresponding door being also made in the outer vessel at L.
A spout conveys away the liquids falling upon the inclined bottom P¹ of the
machine.
When the pulp for paper or other fibrous material has been so thoroughly washed
in this machine that all smell is removed, it is dried by the rapid revolution of the
cylinder to any degree required, and in the manufacture of paper the material
may be removed and packed for carriage or introduced directly into the paper-
making vat.
It may be observed that except for the boilers first described, very little power
is required.
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 improved process for bleaching peat or other fibre, consisting in washing
the peat, then boiling it in water containing a small proportion of alkali, in a closed
vessel provided with agitating devices, under sufficient pressure, then thoroughly
washing it, in plain and acidulated waters, placing it in a bath of diluted
hypochlorous acid solution in which it is agitated for a sufficient time, again
washing it for a sufficient length of time, and finally drying it, substantially as
described,

page_text: 2. For bleaching peat or other fibre, the use of a solution of hypochlorous acid,
prepared and used substantially in the manner herein described.
3. In the process for bleaching peat or other fibre, the boiler having a removeable
cover, an agitating apparatus, an internal heating coil, and pipes and valves for
introducing and withdrawing water and steam, shewn in Figure 1, the washing and
bleaching vessel shewn in Figure, and washing and drying apparatus shewn in
Figure 4, all substantially as described.
4. The process of obtaining hypochlorous acid, by the separate generation of
chlorine and oxygen gases, the purification of such gases in separate vessels, and the
drying and mixing of the two gases by causing them to rise and descend respectively
and simultaneously through a perforated partition provided with desiccating material,
substantially as described.
5. The apparatus for obtaining the hypochlorous acid, consisting of the vessels a, a¹,
for generating the chlorine and oxygen gases, the vessels 1, 1, for purifying the
said
gases, the chamber for mixing and drying the said gases having glass sides and
top, a horizontal partition G, inlet pipes A, and B, above and below the partition
for the chlorine and oxygen gases respectively, and an outlet pipe D for the mixed
gases, substantially as described.
6. The process of further oxidizing the mixed gas by means of electricity, such
process consisting in passing the mixed gases, at a low temperature, through tubes
or passages, in contact with electric sparks, substantially as described.
7. The apparatus for oxidizing the mixed gases by means of electricity, consisting
of an inner glass tube c, c', central wire B, and external coiled wire C (or of carbon
poles) an electrical induction coil J, or other generator, a larger glass tube D, an
outer insulating tube E, and an outer water vessel F, all substantially as described
and shewn in Figure 3.
Dated this 30th day of April 1892.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.