IMPROVEMENTS IN TREATING VEGETABLE SUBSTANCES CHIEFLY APPLICABLE TO THE MANUFACTURE OF PAPER PULP AND FIBRES
Year: 1867

page_text: LETTERS PATENT to William Edivard Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for
the Invention of "IMPROVEMENTS IN TREATING VEGETABLE SUBSTANCES
CHIEFLY APPLICABLE TO THE MANUFACTURE OF PAPER PULP AND FIBRES." -A
communicationfromabroad by Benjamin Chew Tilghman, of Philadelphia,
in the United States of America.
Sealed the 11th June 1867, and dated the 11th February 1867.
PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents; with his Petition, on the
11th February 1867.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Civil Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN TREATING VEGETABLE SUBSTANCES,
CHIEFLY APPLICABLE TO THE MANUFACTURE OF PAPER PULP AND FIBRES," to be as
follows:-
This Invention consists in treating esparto and other grasses, straw,flax, hemp,
wood, and other vegetable substances which contain fibres, with a solution of
sulphurous acid in water under pressures not exceeding that of the atmosphere,
and at a temperature which may be varied from near common atmospheric
Price Sd.

page_text: temperature up to the temperature at which the solution employed would lose all
its acid gas. By this means the cementing matter existing in the vegetable
substances will be either entirely or partially dissolved and the fibrous portion
left in a condition suitable for the manufacture of paper pulp or fibres,
according to the nature of the material employed. The addition of a quantity
of sulphite of lime, or magnesia or soda, or other suitable base to the solution
of sulphurous acid so as to form an acid bisulphite is advantageous by aiding
the chemical action and by improving the colour of the product and enabling
the solution to retain a larger portion of sulphurous acid gas at higher
temperatures than it otherwise would do; acetates and other salts of similar
chemical properties may to some extent be used in place of the sulphites.
The treatment is to be continued until the desired effect is produced, the
time required varying with different materials, wood needs a longer treatment
than straw, esparto, flax, or hemp. The higher the heat or the stronger the
acid solution the more rapid is the solvent action, which will also be assisted
by circulation of the liquid through the pores of the substance and by the
process of displacement, so that fresh acid solution is caused to act upon
substance which has already been partially exhausted of soluble matter, and
the partially saturated liquid is brought into contact with fresh substance;
many kinds of vegetable fibres are considerably bleached by this treatment.
After the acid solution has been used on the vegetable substance it is to be
run off and its remaining sulphurous acid gas either expelled by boiling and
reabsorbed by cold water or precipitated by the addition of hydrate of lime
so as to be available for re-use. The fibrous material is to be well washed to
free it from acid and soluble matter, and is then to be treated by the ordinary
processes of manufacture according to its nature and intended use. The
soluble extract containing the starchy, gummy, and saline constituents of the
plants may be utilized in various ways in the arts and in agriculture.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Edward Newton in the Great Seal Patent Office
on the 10th August 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Civi! Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of February, in the year of our

page_text: Lord One thousand eight bundred and sixty-seven, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me
the said William Edward Newton, Her special licence that I, the said William
Edward Newton, my executors, administrators, and assigns, or such others as
I,the said William Edward Newton, 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 "IMPROVE.
MENTS IN TREATING VEGETABLE SUBSTANCES, CHIEFLY APPLICABLE TO THE MANU.
FACTURE OF PAPER PULP AND FIBRES," being a communication to me from
abroad by Benjamin Chew Tilghman, of Philadelphia, United States of
America,upon the condition (amongst others) that I,the said William Edward
Newton, my executors or adminstrators, 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 afterthe date
of the said Letters Patent.
NOW KNOW YE, that I, the said William Edward Newton,. do hereby
declare the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say):-
This Invention consists in a process of treating flax, hemp, esparto, and
other grasses, straw, wood, and other vegetable substances which contain
fibres with a solution of sulphurous acid in water heated under a pressure not
exceeding that of the atmosphere to a temperature sufficient to cause it to
dissolve either partially or wholly, as may be desired, the intercellular,
encrusting, or cementing matter existing between the fibres, so as to leave the
vegetable substance in a condition suitable for the preparation of fibres for
spinning, or of paper pulp, or for other purposes, according to the nature of
the material employed. It has been found that the addition of sulphite or
bisulphite of lime or other suitable base to the acid solution tends to make
the fibrous product of a whiter color and more easily bleached, and also
helps to retain the acid gas in the solution when heated. If a solution of
sulphurous acid in water be kept boiling at atmospheric pressure it will
gradually lose all its acid gas, but weak solutions of sulphurous acid can be
kept at a few degrees below two hundred and twelve degrees Fahrenheit for a
considerable time with very little loss of acid gas. The solvent action of the

page_text: acid solution upon the intercellular portion of the plants becomes less rapid as
the temperature is lowered and also as the strength of the acid is lessened.
This method of operating with weak solutions of sulphurous acid at tempera-
tures below two hundred and twelve degrees Fahrenheit is chiefly applicable
to the treatment of long fibred plants to obtain fibres for spinning, and where
it is important to avoid pushing the action so far as to weaken the fibres, or
to cases where the comparative simplicity and cheapness of the apparatus
required will inake up for the greater length of time necessary for the complete
extraction of the intercellular matter. In ordinary cases when wishing to
-dissolve out the greater part or the whole of the intercellular matter, as in the
preparation of paper pulp from wood, it is preferable to operate with stronger
solutions of the acid in close vessels under pressure at temperatures exceeding
two hundred and twelve degrees Fahrenheit.
The following is a mode of carrying the Invention into effect upon long
fibred plants to be treated for the preparation of fibres for spinning, taking
for example the case of flax :-A lead lined tub of any convenient size and
shape provided with a close-fitting moveable cover and with a close steam coil
of lead pipe is nearly filled with the flax plants; a solution of sulphurous
acid in water of about specific gravity 1.005 to 1.01, to which has been added
as much sulphite of lime as it will hold in solution at the temperature
employed. is then run in until the plants are covered, suitable means being
employed to keep them below the surface of the liquid during the whole
operation; the mass should be sufficiently open to allow of free circulation of
the liquid and equality of temperature throughout; heat is then applied by
means of the close steam coil until the acid gas begins to be evolved, which
generally takes place at about one hundred and eighty degrees to two hundred
degrees Fahrenheit, and the temperature is kept at that pointora little below
it until samples taken out from time to time show that the fibres are
sufficiently loosened and separable from the stem of the plant and from each
other. It has generally been found that from twelve to eighteen hours are
sufficient, but the trial of the samples is the only reliable guide. Too long a
digestion weakens the fibres, too short a treatment leaves them difficult to
clean and separate. When the operation is finished the acid solution is run
off,and the plants are washed with water until all acid and soluble matters are
removed; they are then dried and the fibres separated from the woody parts
in the usual manner. A subsequent boiling of the fibres in soap water has a
good effect by alternate treatments with hot weak alkaline and sulphurous
acid solutions; the separation of the fibres can be carried to any desired
extent, but there is always a risk of weakening them. The cover of the

page_text: lead lined tub is provided with a lead pipe by which the sulphurous acid gas
which is evolved during the digestion can be conveyed to a suitable condenser
to be absorbed by cold water and re-used. The whole apparatus is under
atmospheric pressure only. Any sulphurous acid remaining in the waste
solutions can be saved either by boiling them and absorbing the gas by cold
water, or by precipitation by hydrate of lime, so as to form sulphite of lime.
Hemp,jute, China grass, and other long fibred vegetable substances, whether
in the state of rough fibre or preferably as entire plants, are to be treated in
a similar manner, but the duration of the operation and the degree of separation
of the fibres will be regulated by the operator in each case according to the
nature of the material and the effect desired to be produced. When the color
of the product is not important the digestion may be performed withasolution
of sulphurous acid alone without the addition of sulphite, and the solvent
action is then more rapid. Renewing the acid solution also quickens the
action. In place of the sulphites other salts of equivalent chemical properties
may be employed.
When esparto or other grasses, straw, or other similar substances are
to be treated to make paper pulp the operation is performed as above
described, and is to be continued with acid solutions renewed from time to
time until the intercellular matter is so much dissolved as to leave the fibrous
portion sufficiently soft and pulpy. Generally from twenty-four to forty-eight
hours is sufficient with annual plants. Wood and other vegetable substances
of several years' growth require a much longer treatment to extract their
intercellular matter. The action of the acid solution is gradual and progressive;
its first effect upon straw, grasses, osiers, young woods, and such like substances
is to make them more flexible and more suitable for making hats, mats,
baskets, hoops, and other articles. When the solvent action is pushed
further the vegetable substance becomes capable of being reduced into coarse
fibres by mechanical beating and rubbing, and is then applicable to the
manufacture of papier maché, pasteboard, and other articles. Finally, by
prolonging the operation until all or nearly all the intercellular matter is
dissolved out the substance can be reduced to very fine fibres suitable for
paper pulp.
I do not confine myself to the kind of apparatus, length of time, degree of
heat, or strength of acid solution above described, as the Invention can be
carried into effect in any convenient way by which vegetable fibrous substances
can be digested with a solution of sulphurous acid in water heated under
pressure not exceeding that of the atmosphere to a temperature sufficient to
cause it to dissolve the intercellular or incrusting matter of the plants.

page_text: I claim as the Invention secured to me under the herein in part recited
Letters Patent treating vegetable substances which contain fibres with a
solution of sulphurous acid in water either with or without the addition of
sulphites heated under a pressure not exceeding that of the atmosphere to a
temperature sufficient to cause it to dissolve the intercellular or incrusting
matter of such vegetable substances so as to leave the undissolved portion in a
fibrous state applicable to the manufacture of fibres for spinning, or of
paper pulp, or to other purposes, according to the nature of the material
employed.
I also claim the use and application of sulphites or other salts of equivalent
chemical properties as above described in combination with a solution of
sulphurous acid in water as an agent in treating vegetable substances which
contain fibres when heated therewith at a pressure not exceeding that of the
atmosphere to a temperature sufficient to cause such acid solution to dissolve
the intercellular or cementing matter of such vegetable substances.
In witness whereof, 1, the said William Edward Newton, have here-
unto set my hand and seal, the Seventh day of August, in the year
of our Lord One thousand eight hundred and sixty-seven.
Witness,
J. W. MOFFATT,
G6, Chancery Lane.
W. E. NEWTON. (L.S.)