IMPROVEMENTS IN THE MANUFACTURE OF PAPER PULP, AND APPARATUS EMPLOYED THEREIN.
Year: 1873

page_text: LETTERS PATENT to John Cowdery Martin, of 5, Upper Hill Street,
Richmond, in the County of Surrey, Manufacturing Chemist, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF PAPER PULP,
AND APPARATUS EMPLOYED THEREIN.
"
PROVISIONAL SPECIFICATION left by the said John Cowdery Martin
at the Office of the Commissioners of Patents, with his Petition,
on the 19th November 1873.
I, JOHN COWDERY MARTIN, of 5, Upper Hill Street, Richmond, in
the County of Surrey, Manufacturing Chemist, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
PAPER PULP, AND APPARATUS EMPLOYED THEREIN," to be as follows:-
The Invention refers more particularly to the pulping of wood and
coarse woody fibres, but parts therof are applicable to the manufacture
of paper pulp from finer descriptions of fibre now used. In operating
upon wood, for instance, I take shavings, sawdust, cuttings, or shreds,
and these I boil in a solution of chloride of sodium, or in a solution of

page_text: chloride of sodium and lime, until the resinous portion of the material is
so far acted upon that the fibres are found to separate in the direction of
their length with a small amount of mechanical force. This force I
apply by using a special form of beating or pulping engine, the object
being to exert a rolling or splitting action on the fibres to divide them
longitudinally, in addition to the scraping action of the ordinary beating
engine which separates them when so divided.
I obtain the desired action by using two rolls in the position of an
ordinary double roll beating engine, one of these to be fitted with bars
and bed plate similar or nearly so to an ordinary beating engine, the
second roll to be fitted with bars thicker than ordinary and rounded at
the edge, and below this roll and in the position of the ordinary bed
plate is placed a third roll smooth or slightly grooved on the surface, and
between which and the projections of the one above the fibres are split
or divided.
I also use to obtain the splitting or dividing action on the fibres a
perfectly smooth bed plate in place of the lower roller.
In place of using the solutions of salt or salt and lime, I treat the
materials previous to pulping with caustic alkaline solutions, or by any
of the methods now practised.
I also for some varieties of paper pulp convert the material after
boiling at once into pulp, by the continued action of the pulping engine,
or into the fibrous condition of half stuff, which may be treated with
chlorine or chloride of lime, and afterwards beaten into pulp.
For other varieties I treat the half stuff with chlorine gas or chloride :
of lime, & boil it in a solution of caustic alkali, and again bleach it,
when a slight beating converts it into a fine pulp.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Cowdery Martin in the Great Seal Patent
Office on the 19th May 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
COWDERY MARTIN, of 5, Upper Hill Street, Richmond, in the County of
Surrey, Manufacturing Chemist, send greeting,
3

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of November, in the
year of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Cowdery Martin, Her
special licence, that I, the said John Cowdery Martin, my executors,
administrators, and assigns, or such others as I, the said John
Cowdery Martin, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF PAPER PULP, AND APPARATUS
EMPLOYED THEREIN," upon the condition (amongst others) that I, the said
John Cowdery Martin, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said John Cowdery Martin, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the Drawings,
(that is to say) :-
The Invention refers more particularly to the pulping of wood and
coarse woody fibres, but parts thereof are applicable to the manufacture.
of paper pulp from finer descriptions of fibre now used. In operating
upon wood, for instance, I take shavings or other convenient pieces, and
these I boil in a solution of chloride of sodium, or of chloride of sodium
and lime, until the resinous portion of the material is so far acted upon
that the fibres are found to separate in the direction of their length with
a small amount of mechanical force. This force I apply by using a
special form of beating or pulping engine, the object being to exert a
rolling or splitting action on the fibres to divide them longitudinally, in
addition to the scraping action of the ordinary beating engine, which
separates them when so divided.

page_text: I obtain the desired action by using two rolls in the position of an
ordinary double roll beating engine, one of these to be fitted with bars
and bed plate similar or nearly so to an ordinary beating engine, the
second roll to be fitted with bars thicker than ordinary, and rounded at
the edge, and below this roll and in the position of the ordinary bed 5
plate is placed a third roll, smooth or slightly grooved on the surface,
and between which and the projections of the one above the fibres are.
split or divided.
I also use to obtain the splitting or dividing action on the fibres a
perfectly smooth bed plate in place of the lower roller.
In place of using the solutions of salt or salt and lime I treat the
materials previous to pulping with caustic alkaline solutions, or by any
of the methods now practiced.
I also for some varieties of paper pulp convert the material after
boiling at once into pulp by the continued action of the pulping engine,
or into the fibrous condition of half stuff, which may be treated with
chlorine or chloride of lime, and afterwards beaten into pulp.
For other varieties I treat the half stuff or pulp with chlorine gas or
chloride of lime, and boil it in a solution of caustic alkali, and again
bleach it, when a slight beating converts it into a fine pulp.
In operating upon wood shavings, for example, I soak them for about
twelve hours in a solution of chloride of sodium, or of chloride of sodium
and lime. I prefer the mixture of chloride of sodium and lime, the
strength being from about six to ten per cent. by weight of chloride to
the water used, and about half that quantity of quick or caustic lime.
Chloride of calcium or other alkaline or earthy chloride having
analagous properties to chloride of sodium may be used.
Sea water which contains on an average about three per cent. of
chloride of sodium and some chloride of magnesium may be used, and a
further quantity of chloride together with the lime added to it.
The proportions of the chloride of sodium and lime may vary, but I
prefer the chloride to be something in excess of the lime, as it protects
the fibres of the material from the corrosive action of the latter.
After soaking for twelve hours the shavings are to be boiled in the
solution in an open vat or kier or other suitable vessel for from about
]

page_text: four to six hours; they are then to be removed from the kier and
washed, and reduced to pulp in the pulping or beating engine to be
presently described.
The pulping engine I employ, of which the several Figures One, Two,
and Three in the Drawing shew a longitudinal section, cross section, and
plan respectively, is in general arrangement similar to an ordinary
beating engine working with two rolls, one behind the other in the usual
trough, and having the usual means of raising and lowering the rolls,
but in place of the ordinary bed plate under one of the rolls I use a
lower roll, which may be termed the bed roll, smooth by preference on
its surface. The upper roll has spaces formed in its periphery, in order
to permit a flow of the material through the apparatus, and a continuous
feed of the fibres to be pulped.
To prevent any accumulation of fibres interfering with the free action
of the lower or bed roll within the case in which it works, this case is
made something larger than the roll, which latter is placed excentriccally
with regard to it, as shewn, the surface of the roll bearing slightly
against it on the side. Should any fibres pass in this way they will
meet with a constantly increasing width of space, and be ejected by the
action of the bed roll, and so caused to flow through the apparatus.
The splitting or dividing action of the machine is more energetic when
the parts nearest in contact and between which the fibres pass are
comparitively narrow; I therefor prefer to construct the upper roll
with bars similar to an ordinary beating engine, but something thicker,
and in place of having the usual chisel-edged form of section I make the
edge semicircular or rounded off, as shown in Figure Six.
The upper roll, shewing the arrangement of bars and spaces is
marked a, and the roll working below it b, and to ensure an equal speed
between the outer edges of the bars of the top roll and the surface of
the lower roll the shaft of the latter is brought through the side of the
trough, and geared with that of the upper roller, as shewn at'd on
Drawing. In some cases, however, I use the lower or bed roll without
the shafting projecting through the side of the trough, but I prefer the
arrangement as shewn.
The thickness of the bars of the roll a, and the consequent amount of
space between them may vary with the nature of the material to be
pulped. For wood I prefer the bars to be about half to three-fourths of

page_text: an inch in thickness, so that the space in contact with the fibres may be
small. With softer materials the surface may be wider, as shewn at
Figure 4 on Drawing, and they may be either formed in the substance
of a metal roll, or attached to a wood or metal one, as shewn.
Immediately behind the upper roll just described is placed a second roll
marked c, and beneath it a bed plate, both fitted with bars formed
similar to an ordinary beating engine, and the bars may have similar
spaces between them, but I prefer when the material requires the
greatest amount of splitting or longitudinal seperation without undue
shortening of the fibres that the bars should be thinner than usual,
about three-sixteenths to one-quarter of an inch thick, and arranged a
number together and then a space, as shewn on the roll c on Drawing.
Figure five shews detailed arrangement for fixing the bars to the roll,
and for removing them for the purpose of sharpening. e is a thick or
supporting bar, to which is attached the pin f, of which there are four in
the length of the bar. The remaining bars are loosely fitted on to these
pins, the further ends of which fit into and are held by the plate g,
secured to the opposite side of the opening in the roll. The whole is
held in place by the wedge-shaped piece / fixed to the roll, and when
this is taken out the bars can be readily removed and sharpened.
The action and manner of working the apparatus is as follows:―The
roll marked a, and having the roll 6 below it, is to be lowered to exert
pressure upon the fibres, which causes them to split or divide from each
other, the fibres then passing to the roll immediately behind it marked c,
which roll is at the commencement of the operation set to work upon
the material with a light pressure, so as to produce a merely rubbing
action upon the fibres, and seperate them from each other without much
shortening, but as the work proceeds and the fibres are found to be
sufficiently split or longitudinally divided the roll is lowered closer to
the bed plate, and the fibres shortened and pulped in the usual manner,
and the pulp so produced is suitable for most varities of unbleached
paper.
In place of the lower or bed roll 6 I employ a perfectly smooth bed
plate of iron or other suitable material under the roll a above described,
and either concave, convex, flat, or other convenient form, but I prefer
the bed roll described.
When it is required to produce paper stock as a merchantable article
in the form of half stuff or partly prepared fibres, and it is necessary that

page_text: these shall be as little reduced in length as possible, I prefer while
splitting or dividing and cleaning them that the edges of the bars of the
second roll c together with its bed plate shall not be used in too sharp a
condition.
The solutions of the chlorides and lime I use in sufficient quantity to
thoroughly saturate the material, keeping up a circulation by any of the
well-known methods now employed.
I do not confine myself to the methods of preparation of the materials
above described when using the special pulping engine, as I sometimes
boil the material intended to be pulped in a solution of caustic alkali, or
prepare it for pulping in any other convenient manner.
Wood shavings may also be reduced to pulp in the above-described
pulping engine, after being simply soaked or boiled in water. Also after
being sufficiently boiled in a solution of lime and chloride of sodium, as
herein-before described; wood shavings and various other fibres may be
reduced to a pulp more or less coarse or fine, according to the nature of
the material, by beating in an ordinary beating engine, but I prefer to
unite the processes of boiling the materials in a solution of the salt and
lime, and pulping in a pulping engine constructed as above described.
Although wood is described as the material under operation, the
process is applicable to other woody fibres, such as bamboo cane, sugar
cane, rice straw, plantain fibre, and other materials of a like kind; also
to the straw of the various cereals, esparto grass, pine apple fibre, &c.,
and to all fibres requiring to be separated or divided from each other
longitudinally as well as shortened in the ordinary manner of pulping,
but with the exception of wood I do not use the solutions of the
chlorides without the addition of lime in preparing the material, and
with this only when the fibres are not to be bleached.
To operate upon a material such as bamboo cane I previously split it
by passing the cane through rollers, by preference finely corrugated,
such corrugations being in a direction transverse to the axis. The sugar
cane material is by preference the ordinary megas or cane trash after the
cane juice has been pressed out.
To bleach wood shavings prepared with the chlorides and lime, and
after they have been sufficiently acted upon by the pulping engine and
reduced to a long fibrous pulp or thoroughly equalised half stuff, I treat.

page_text: the material with a solution of chloride of lime, to which I very
gradually add sulphuric acid, and I continue the addition of chloride of
lime solution and sulphuric acid until the material retains a sensible
odour of free chlorine, and I add the sulphuric acid sparingly from time
to time, disengaging no more chlorine than the colouring matter and
resin of the material can absorb, and I leave the solution sensibly acid
to the taste; or in place of using chloride of lime I enclose the pulped
material combined with water in any suitable apparatus constructed to
contain water and prevent the escape of gas, and in which the material
can be agitated, and submit it to the direct action of chlorine gas. I
prefer to use an apparatus similar to an ordinary poaching or bleaching
engine, fitted with a close cover for this purpose, and having as little
ironwork as possible, which is to be closely covered with lead to protect
it from the action of the gas. I add as much lime as the water
will dissolve before admitting the gas, which is to enter the apparatus
in just such quantities as the fibres can absorb, the action of the roll
offering a continually fresh quantity of material to the action of the gas,
and when a portion of the fibres on being removed retain for some time
the odour of free chlorine I stop the entry of the chlorine gas, and
slightly acidulate the water with sulphuric acid.
After being treated with chlorine, as described, the pulp is thoroughly
washed in the washing engine, and boiled in a solution of caustic alkali
of a strength of about one and a half to two per cent. by weight of the
water used. After being again washed it may be bleached with chloride
of lime, and soured with sulphuric acid in the usual manner; or after
the fibre, whether wood shavings or other material, is pulped I boil it in
a solution of caustic alkali of the strength of about two to three per cent.
by weight of the water used, and bleach it with chloride of lime, and
the operation is quickened if a little carbonate of soda (the soda crystals
of commerce) is added to the bleach.
Also for some purposes the pulp may be sufficiently bleached with
chloride of lime, with or without the addition of carbonate of soda
directly after pulping, and without being previously boiled in an
alkali.
In applying this. Invention to the manufacture of pulp the dangerous
high pressures now employed in pulping wood are not necessary, and
are sought to be avoided; at the same time the moderate pressures used

page_text: in boiling rags and other materials may be employed, if desired, and are
advantageous in the case of boiling the pulp in alkali for bleaching.
Having now described the nature of my said Invention, and the
manner in which the same is to or may be performed, I would have it
understood that what I claim and intend to be secured by the above in
part recited Letters Patent is,—
Firstly. The preparation of wood and other fibrous material previous
to pulping by treating it with a solution of chloride of sodium, chloride
of calcium, or other chlorides of a like kind, mixed or not with lime.
Secondly. The use of chlorine gas or chloride of lime applied to fibrous
materials when prepared with chlorides and lime, as and for the purposes
described.
Thirdly. The construction, arrangement, and adaptation of the rolls of
pulping engines, substantially as described and illustrated and for the
purposes set forth.
In witness whereof, I, the said John Cowdery Martin, have here-
unto set my hand and seal, this Nineteenth day of May, in
the year of our Lord One thousand eight hundred and seventy-