IMPROVEMENTS IN THE PREPARATION OF WOOD OR OTHER LIGNEOUS OR VEGETABLE MATTER FOR THE 'MANUFACTURE OF PAPER, CARDBOARD, AND OTHER ANALOGOUS PRODUCTS
Year: 1873

page_text: LETTERS PATENT to Bristow Hunt, of Serle Street, Lincoln's Inn,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN THE PREPARATION OF WOOD OR OTHER LIGNEOUS OR
VEGETABLE MATTER FOR THE 'MANUFACTURE OF PAPER, CARDBOARD, AND
OTHER ANALOGOUS PRODUCTS."-A communication from abroad.by
Oswald Moth and Heinrich Voelton of Dania Elmanca
.
PROVISIONAL SPECIFICATION left by the said Bristow Hunt at the
Office of the Commissioners of Patents, with his Petition, on the
19th April 1873.
I, BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN THE PREPARATION OF WOOD OR OTHER. LIGNEOUS
OR VEGETABLE MATTER FOR THE MANUFACTURE OF PAPER, CARDBOARD, AND OTHER,

page_text: .
ANALOGOUS PRODUCTS," (a communication to me from abroad by Oswald
Meyh and Heinrich Voelter, of Paris, France), to be as follows:-
This Invention consists,-
Firstly. In exposing the wood in shreds during a suitable time to the
action of steam or other vapour or mixture of vapours superheated to a
convenient number of atmospheres in a suitable vessel, and then (a) to
transform it immediately by any known process, preferably by a mill or
other suitable arrangement, into a pulp or mass suitable for the
manufacture of paper, pasteboard, or other analogous product; or
before this transformation (d) to treat it by the aid of a vacuum, and
at suitable pressure at a high temperature to dissolving agents (either
fluids or in the form of gas) which are employed mixed (eventually)
alternately or even in an intermittent manner, and which may be
followed by steam for washing the same if desired. (c) to treat the same
(also by the aid of a vacuum and at a suitable pressure at a high
temperature) with agents, either fluid or in the form of gas, which will
bleach the same, and to transform it then only into pulp for paper or
pasteboard.
Secondly. In exposing the wood reduced to shreds, or straw, or
other vegetable fibrous matter of any kind suitable for the manu-
facture of paper, to the action of steam or vapour, and then (a) either
to transform it at once (by one of the methods above mentioned)
into pulp for paper or pasteboard; or before this transformation (6) to
proceed as before indicated under the heading "Firstly (6)," and then
(c) to treat it with dissolving agents (that is to say, agents which will
bleach it) and then only to transform it into pulp for the manufacture of
paper and pasteboard.
Thirdly. In treating other fibrous vegetable matters "half stuff" or
"whole stuff," threads, woven fabrics, and so forth, as above indicated
by dissolving and bleaching agents, and then to work them. What the
Inventors therefore desire to protect by Letters Patent is, the process
which consists in treating wood in shreds, or in the reduced state, and
other suitable fibrous vegetable materials in any form, with substances in
the form of steam or vapour, or in the form of gas, such as ammoniacal
or other gas for example, that is to say, to soften or disaggregate them
more or less by means of a lye, and to bleach them by employing for the

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Bristow Hunt in the Great Seal Patent Office on
the 18th October 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BRISTOW
HUNT, of Serle Street, Lincoln's Inn, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of April, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors
give and grant unto me, the said Bristow Hunt, Her special licence
that I, the said Bristow Hunt, my executors, administrators, and
assigns, or such others as I, the said Bristow Hunt, 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 PREPARATION OF WOOD OR OTHER LIGNEOUS OR VEGETABLE MATTER FOR THE
MANUFACTURE OF PAPER, CARDBOARD, AND OTHER ANALOGOUS PRODUCTS," (a
communication to me from abroad by Oswald Mejh and Heinrich
Voelter, of Paris, France), upon the condition (amongst others) that I,
the said Bristow Hunt, 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 Bristow Hunt, do hereby declaro
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
.

page_text: following statement. in writing, and on reference being had. to the
accompanying Sheet of Drawings, that is to say:-
This Invention relating to the preparation of wood or other ligneous
or vegetable matter for the manufacture of paper, cardboard, and other
analogous products, consists in exposing shreds or fibres of wood during.
several hours in a suitable steam tight reservoir to the action of steam at
a pressure of three or four atmospheres, and then submitting them after
this process to a subsequent treatment. By this process of absorption
and inasmuch as the steam penetrates into the interior of the wood. and
dissolves a mass of glutinous substances, the wood becomes altogether
soft and presents to the fibring machine (Voelter's system) a matter.
which possesses in an extraordinary manner the property of being felted,
but which is more or less of a brownish color. This matter (especially
if it is from pine wood) without the addition of rags, form a very useful
paper and cardboard, and besides requires for its manufacture less
motive power than if the wood had not been submitted to the process
of' absorption..
There is annexed hereunto a Drawing of a spherical reservoir shown:
in longitudinal section at Figure 1, and in end view at Figure 2. It:
may however be made in any other form, and should be sufficiently
strong and provided with suitable man-holes T and T for the introduction.
and removal of the matters to be treated by the steam, which latter is;
produced in a suitable generator and admitted into the reservoir by the
tap or valve R. This reservoir is provided with another tap R¹, by
which the water of condensation which is produced may be discharged,
that is to say, with the extractive matters. Also if the reservoir is of a
weaker construction than the steam boiler or generator, it should have a
manometer M and a safety valve S suitably weighted. It is preferable
also to apply to the reservoir a perforated double bottom F above the
discharge tap R¹ for the water of condensation and extractive matters,
especially if treating matters of small volume.
An absorption reservoir arranged as here described may as above
stated be made of any form, provided that it possesses a suitable strength
and is of a size proportioned to the work to be done. It may also be
horizontal or vertical, and may consist also of a boiler for cooking rags,
which is supplied with steam like that ordinarily employed in paper

page_text: manufactories, that is to say, arranged so as to revolve, if such boiler is
not constructed after the primitive system of "Donkin," wherein the only
part which revolves is an interior perforated drum, which contains the
material to be boiled, whilst the exterior boiler properly so called is
immovable.
If desirable instead of a separato steam generator the absorption
boiler may be constructed of one piece with the generator, provided that
the latter is sufficiently high and arranged as shewn in the vertical
section, Figure 3, so as to receive the matters to be operated on at a small
distance above the highest level x, x¹, of the water employed, and in tho
space reserved for the steam generator a false bottom may be employed,
and above that a double perforated bottom f¹, and also a steam pipe g
which forms a communication between the two compartments. A.
regulating tap worked from the outside is mounted on this pipe.
. It is necessary for the removal (cither into another vessel or directly
into the air) of the steam which remains after the expiration of the time
necessary for the absorption to admit a current of air into the apparatus ;
this end may be obtained by opening dampers on the opposite sides or
ends; this current of air is necessary in order that the acid vapours may
cscape as long as the apparatus (which is ordinarily of iron) remains hot,
and not strike upon the walls of the apparatus and oxidize them.
It should be mentioned that there is still the absorption of wood which
has been previously reduced in any manner, either by planing, rasping,
or otherwise wood, chips, or sawdust, which answers the purpose well;
the result obtained is also (according to the degree of this previous
reduction after the absorption in the " cylinder mill" for the "half
stuff," and then in the "refiner" of the "Voelter" machine) a very
useful paper pulp because it is most susceptible of being felted than that
which has hitherto been obtained from these materials. After this
powerful solution by steam of a part of the glutinous matters of wood,
there remains caustic lye (though weak), lye of soda or of oxide of
sodium, and even of milk of lime, which have a considerable effect, that
is to say, that they act on the substances which still adhere to the
cellulose, which not only causes a considerable improvement in the
quality of the paper pulp obtained therefrom, but also the trans-
formation of the wood into paper material is facilitated. In this manner

page_text: a product may be obtained much better (although rather dearer) than
that obtained by the processes hitherto employed. The influence of the
steam and of the lixiviation which takes place afterwards with a con-
siderable economy of alkali, is applicable to all other fibrous materials,
principally those which are crude and not yet submitted to treatment
with lyes, such for example as straw, exparto, flax, hemp, cotton, &c., and
for half products, and whole products, such as thread, woven fabrics,
and so on.
I would further remark that according to the Inventor's experience.
wood, which (either in its natural state or reduced to pieces) has been
treated with steam at a high pressure, and is consequently softened in
its structure may be transformed into cellulose which can be bleached,
and that by subsequent admission of other solvent matters; this applics
also to wood which should not be bleached in the following manner :-By
this treatment with high-pressure steam there is obtained not only a com-
plete softening of the wood, but also a complete removal of the air which
is in the apparatus and in the pores of the wood. By the aid of this
vacuum it is possible to conduct solvent liquid (caustic lye of soda, for
instance, of a suitable concentration) with greater surety into all the
crevices of the wood, or, at the moment when the process of absorption
is nearly completed the tap for the admission of steam must be shut,
which allows the water of condensation to escape; a third tap must then
be opened which is in communication by a conduit with a vessel the
capacity of which is rather in excess of that of the absorption vessel,
and which is filled with a caustic lye of soda, cither cold or hot.
When by the exterior cooling of the absorption vessel (which is
separated hermetically from the rest) the volume of the steam which
remains therein diminishes at once, the caustic lye of soda which
has been held in readiness is carried into the absorption, effecting the
condensation of the steam and establishing a vacuum, which in pro-
portion as it is formed is filled with the said lye. As soon as the tem-
perature of the caustic lye of soda falls below that of boiling water the
condensation of steam is complete, and the vacuum which is obtained
allows the liquid to penetrate into the remotest pores of the wood which
has already been previously softened.
In order that the solvent qualities of the caustic lye of soda or other
similar liquids may have a good effect the latter should be heated by

page_text: the admission of steam at a pressure of several atmospheres. When this
has been sufficiently effected the passage of the steam must be closed and
the lye (which may serve for several times) is allowed to flow, and causes
by the exposure to the air of the absorption vessel an evaporation of the
wood impregnated with the lye, and heated according to the pressure
of the steam employed considerably above one hundred degrees. By
this means an essential concentration of the lye which adheres to the
wood takes place, which has this advantage, that it is possible to
work, even at the commencement with much weaker lyes, and conse-
quently with less expenditure of caustic soda. The shreds of wood which
have been saturated in this manner with the caustic lye of soda, &c.,
is transformed either immediately in a suitable manner (by tearing,
grinding, crushing, or otherwise) in ligneous matter, and washed at the
same time, or it is submitted to another absorption as above described,
and by effecting this absorption in an intermittent manner the washing
is performed separately, obtaining a cellulose tinged with brown which
can then be submitted to a bleaching process by means of chloride of
lime or other agent.
When treating wood which has been previously reduced into small
picces, or such matters as lie very close together during the operation, it is
necessary to have a rotary boiling apparatus on the "Donkin" system as
above mentioned, in the outer envelope of which the extractive matters
can separate themselves. If the absorption vessel is lined with lead
there is nothing to prevent (after the washing by means of the vacuum
and the employment of the lye) the chloride of lime being admitted into
the vessel and removed therefrom after the necessary duration of time,
and then, if desired, introducing steam again for washing. But as the
effect of the steam at a high temperature is excessively favourable other
matters may also be employed in the form of vapour or gas instead of
liquid, which matters serve to separate the substances to be disintegrated
and for bleaching. At first instead of the caustic lyc of soda, which is
now most usually employed, and the regeneration of which is very
costly, an alkali was discovered in the form of gas (ammonia), and by
experiment the anticipated result was established.
The wood, whether it has been submitted to absorption or not and
reduced to small pieces, or in its natural state, is placed in the absorption
vessel constructed as above described, and treated at a high temperature

page_text: . (that is to say at a pressure which corresponds with the latter) with the
vapour of hydrated ammonia (spirit of ammoniacal salt). Steam being
carried across, filled up to a certain height with ammonia, and becoming
consequently ammoniacal, vapour is employed exactly in the same
manner as steam in the other case, with this exception, that the former
after having produced its effect upon the wood by disaggregating, it is
conducted with the extractive matters and the water of condensation
into a second vessel, which is filled partly with milk of lime for cleansing
.it. Thence after having passed through any known refrigerator it is
recovered without serious loss as hydrated ammonia, and used over again.
The wood, which has been disaggregated at one operation with
ammonia in the form of vapour or by an intermittent treatment (in
certain cases, as for example for straw, by an alternate treatment with
liquid caustic soda) can when it is in small picces be reduced at once to
fibrous matter for bleaching, or before such reduction may be treated
with bleaching matter either in the form of gas by charging high-
pressure steam with chlorine gas or in the liquid state. This latter
treatment may also be employed in connection with the absorption
process when all the ammoniacal gas contained in the wood has been
.driven out.by pure steam and a vacuum produced to cause a very great
penetration of the chloride of lime into all the crevices of the wood.
.
There also as regards the preparation for bleaching, besides chlorine,
other matters in the form of gas, such as gases from acid of salt,
sulphurous acid, ozonized oxygen, sub-chlorous acid, &c., which acting
on the agglutinated parts dissolves a portion directly, another portion in
a different manner by oxydation, which reduces them to such a state
that they are readily taken hold of (according to the Inventors' experi-
ence) by alkaline liquids, even by those which are rendered more fluid.
If it be only mainly desired to free the wood from substances which
impart to the ligneous matter the quality of turning brown under the
action of light, it would be proper without previously employing steam,
by which principally pine wood assumes a brown colour, to treat it with
vapour of alcohol, or of cther, sulphurous substances from coal, benzine,
oil of turpentine, or other matters which extract these substances, in
such a manner as to obtain a matter of the primitive and natural colour
of the wood.

page_text: Having now described the nature and object of the said Invention for
"Improvements in the Preparation of Wood or other Ligneous or
Vegetable Matter for the Manufacture of Paper, Cardboard, and other
Analogous Products," together with the manner in which the same is to
be or may be performed or carried into practical effect, I would remark
in conclusion that this Invention (communicated to me by the above-
named Oswald Meyh and Heinrich Voelter) consists, --
Firstly. In exposing the wood in shreds during a suitable time to the
action of steam or other vapour, or mixture of vapours; superheated to a
convenient number of atmospheres in a suitable vessel, and then (a) to
transform it immediately by any known process, preferably by a mill or
other suitable arrangement, into a pulp or mass suitable for the manu-
facture of paper, pasteboard, or other analogous product; or before this
transformation (b) to treat it by the aid of a vacuum, and at suitable
pressure, at a high temperature to dissolving agents (either fluids or in
the form of gas) which are employed mixed (eventually) alternately or
even in an intermittent manner, and which may be followed by steam
for washing the same if desired. (c) to treat the same (also by the aid
of a vacuum and at a suitable pressure at a high temperature) with
agents, either fluids or in the form of gas, which will bleach the same,
and to transform it then only into pulp for paper or pasteboard.
Secondly. In exposing the wood reduced to shreds, or straw, or other
vegetable fibrous matter of any kind suitable for the manufacture of
paper to the action of steam or vapour, and then (a) either to transform
it at once (by one of the methods above mentioned) into pulp for paper
or pasteboard, or before this transformation (b) to proceed as before indi-
cated under the heading "Firstly (b)," and then (c) to treat it with
dissolving agents (that is to say agents which will bleach it), and then
only to transform it into pulp for the manufacture of paper and paste-
board.
Thirdly. In treating other fibrous vegetable matters, "half stuff," or
"whole stuff," threads, woven fabrics, and so forth, as above indicated,
by dissolving and bleaching agents, and then to work them.
What the Inventors therefore claim under the above recited Letters
Patent is, the process consisting in treating wood in shreds or in the
reduced state and other suitable fibrous vegetable materials in any form,

page_text: with substances in the form of steam or vapour or in the form of gas,
such as ammoniacal or other gas for example, that is to say, to soften or
disaggregate them more or less by means of a lye, and to bleach them
by employing for the two purposes indicated successively or inter-
mittently alkalies and chlorine in a fluid state and by the aid of a
таспи
In witness whereof, I, the said Bristow Hunt, have hereunto set my
hand and scal, this Seventeenth day of October, in the year of
our Lord One thousand eight hundred and seventy-three.