Improvements in the Treatment of Vegetable Substances for the Manufacture of Paper Stock, Pulp, or Fibre.
Year: 1888

page_text: 410111
baby
United States of America.]
Improvements in the Treatment of Vegetable Substances for the
Manufacture of Paper Stock, Pulp, or Fibre.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co. Patent Agents,
Southampton Buildings in the County of Middlesex, 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 :-
My process relates to the treatment of various kinds of wood such as Pine, Spruce,
Hemlock Linden, Fir, Poplar and other wood; and of straw, such as Rye, Wheat,
Barley and Oats and of various grasses containing fibre, and of plants such
as Flax, Jute, Manilla &c., which contain fibre suitable for making paper stock, and
also for the treatment of Hulls, Seeds, or for separation of cotton fibre from the
same.
My process consists primarily, in circulating within a steam-tight vessel and
through the vegetable material contained therein, a chemical liquor, of which liquor
a portion will circulate from the lower end of the vessel or digester, upwardly to
about the middle of length of the same and another portion will be circulated
downwardly after being drawn from a point at near the middle of length of the
vessel, and then be introduced into a chamber at the upper end of the digesting
vessel, to be sprayed down upon the mass so as to percolate uniformly through the
material to about the middle of length of the saine-when it will be again drawn from
the vessel, and be returned as before; and secondarily it consists in circulating a
chemical cooking liquor through a steam heating chamber or chambers, and thence
through the mass of material being treated therein, in two directions, by which one
portion of the liquor after being heated will circulate upwardly through the lower
half portion of the mass, and another portion be circulated downwardly through
the upper half portion of the same; further, it consists in subjecting vegetable
substances to the action of the chemical cooking liquor, which is being continuously
heated by its having continuous passage through suitable steam heating chambers
or devices and thence being discharged into the mass of material and circulated in
two directions, with one portion of the liquor having a continuous circulation
upwardly through the mass from the lower end of the same, to about the midway in
its length, and another portion through the upper half of the mass, from above and
toward the middle of length of the vessel.

page_text: In the practice of my process I preferably employ a cylindrical shaped vessel
constructed of Iron or Steel with its parts suitably united by rivets, the same as in
a steam boiler, so as to sustain a pressure from twenty to one hundred and fifty
pounds per square inch, accordingly as the materials to be treated, may require for
their complete reduction to fibre.
This vessel I prefer to stand in an upright position though in some cases it may
be horizontal yet for general purposes I would construct the vessel with the length
of about twenty-four feet and with a diameter of from six to seven feet. This vessel
has within it, at near its lower end, a perforated bottom or strainer and a second
strainer in its upper end.
Between the ends of the chamber of this digester and extending from one to three
feet in each direction from the middle of its length is an annular liquor chamber
formed between the outer shell of the digester and an interior perforated wall-
which is set at a distance of from one to three inches from the former.
Within this digester are employed a system of liquor circulating pipes and a suitable
pump by which the liquor is drawn from this annular chamber and is discharged,
with one portion forced from the outlet of the pulp, into the lower end of digester
to circulate upwardly through the lower half of the mass of material being treated,
while another portion will be forced upwardly through a suitable pipe and discharged
into a chamber above, to be sprayed downwardly on the material below so as to
thoroughly saturate the same, and then percolate downwardly to the liquor line in
the chamber of the vessel where it will be mixed with the liquor from the portion
circulated upwardly, and with the same, escape into the narrow annular chamber
(at the middle of the digesting vessel) to be again drawn by the pump to be circulated
in both directions as above stated.
In some cases I place within the lower end of the chamber of the digesting
vessel a liquor heating apparatus consisting of a steam chamber, contained within
suitable walls of its own, and provided with a series of tubes through which the
cooking liquor can be made to circulate upwardly from below, to a distance below the
perforated bottom or strainer.
In some cases, I use within the digester a second liquor heating device, consisting
of a steam chamber, surrounding a series of pipes, through which the cooking liquor
will pass from above to the material below, in small streams, so as to spray the
material and then percolate downwardly through the same to mingle with the liquor
rising upwardly through the mass from below. When the vegetable material to be
treated is wood, such as Pine, Spruce, Poplar, Linden &c. I reduce the same to small
pieces by any suitable machine adapted to cut the same into chips. These chips are
preferably dried before introduced within the vessel. After the vessel has been filled
with these chips of wood, the chemical liquor will be introduced in quantity sufficient
to fill up the vessel to a little past the point from which the draft pipe will draw the
liquor from the annular chamber at the middle of length of the digesting vessel. The
man-hole will then be tightly closed so as to prevent the escape of any steam from
the vessel while the charge of material is being treated. The cooking liquor is then
circulated by means of the pump or pumps, with one portion of the liquor entering
the mass of material from below, to be circulated upwardly through the same, by the
force of the pump or pumps while another portion of the liquor will be introduced'
into the liquor chamber above the charge and be sprayed down upon the same
through small perforations made in the spraying device and thereby saturate the
upper half portion of the material by percolating downwardly through the same to
the liquor line, at about the middle of length of the digesting chamber. Under these
conditions of circulation of the cooking liquor the lower half portion of the charge
will be continuously submerged, while the upper half portion of the same will be
continuously saturated and these two portions the one submerging the lower half
portion and the other saturating the upper half portion will move gradually toward
each other and meet at near the middle of length of the charge and be together
drawn out into a narrow annular chamber at about the middle of the mass and thence
through a draft pipe to the pump or pumps to be again returned-with one portion

page_text: forced to circulate upwardly through the lower half, and the other to be circulated
downwardly through the upper half as above described. The action of the pump or
pumps being continued, this dual circulation, with one portion flowing downwardly and
another portion flowing upwardly through the mass, will be continued until the
material has been completely disintegrated or reduced.
When straws, grasses or other small plants are to be treated, I prefer to reduce the
same to small pieces by means of suitable machines and then introduce the same into
the chamber of the digesting vessel together with the chemical cooking liquor sub-
stantially the same as with wood chips. This cooking liquor will then be circulated
in substantially the same manner through the mass of cut straw or grass, as through
the wood chips, until all the soluble portions of the same become dissolved and the
disintegrated fibres have become loosened.
In the reduction of Pine, Spruce and similar woods containing pitch, I prefer to
use in this process a chemical cooking liquor made from caustic soda with a degree
of strength of about from 8 to 10 degrees Beaumé, at 60 degrees Fahrenheit which
liquor is made to have a dual circulation through the Pine or Spruce chips, with one
portion circulating upwardly, through the lower half of the mass of material, and
another portion downwardly, through the upper half portion of the same, as above
described, for from about 8 to 10 hours, and under a pressure of steam heat of about
from 100 to 120 pounds per square inch.
With poplar, Linden, Willow and similar woods, I make this liquor with a strength
of about from 5 to 8 degrees Beaumé, at 60 degrees Fahrenheit, and circulate
the same as above described under a pressure of from 80 to 120 pounds per square
inch.
For the reduction of flax or tow or linen or rags 1 employ this cooking liquor at
about 4 degrees Beaumé, at 60 degrees Fahrenheit, for about 3 hours. Old Manilla
rope, Jute butts, grasses &c. may be treated with this alkaline liquor at from 2 to 4
degrees strength, at about 60 degrees Fahrenheit, with a circulation of about 3 hours
under a pressure of from 60 to 100 pounds per square inch. For Rye, Wheat and
other straws I would use a liquor of strength from to 3 degrees strength Beaumé,
at 60 degrees temperature Fahrenheit, with a circulation of from 1 to 3 hours under
a pressure of from 30 to 60 pounds per inch.
It should be understood that under the higher pressure at which the cooking
liquor is circulated a less strength of liquor may be used, and that when the strength
of the liquor is increased, the heat pressure of the same and time of its circulation
may be reduced; and that with weaker liquor and lower pressure the time of its
circulation should be lengthened.
Care should be, in all cases taken that when the stronger liquors are used, the
times of circulation of the same should be lessened, so that when the lignine is
dissolved the fibre will not be injured.
The accompanying drawing illustrates a digesting vessel which can be employed
for the practice of this process, and shows this vessel to be formed by the shell A
(which can be made of iron or steel, with its parts suitably riveted together in a steam
tight manner) and provided with a man-hole a and cover at the upper end. The
digesting chamber B is shown to be situated between the lower perforated bottom b
and the upper perforated piece 6. The drawing shows below the lower perforated
bottom a liquor heating device C which is heated by steam and contains a pipe c
through which the cooking liquor is upwardly circulated from below. The drawing
also shows a liquor heating device D heated by steam in the upper end of the digest-
ing chamber and above the upper perforated plate 62 and containing the liquor pipes d
through which the cooking liquor will be introduced into the digesting chamber from
above. The drawing also shows at near the middle of length of this digesting vessel,
an annular chamber E having its internal wall perforated for the passage of the
cooking liquor from the digesting chamber B, to the draft pipe G. The drawing also
shows this chamber E to be connected by draft pipe G with the inlet of the pump F;
and that two discharge pipes I and J connect the outlet of the pump with the
digester, the former discharging into the lower end of the digester, from which

page_text: the liquor will be forced up through the liquor pipes c in the lower heating
device C to be discharged from thence into the chamber below the perforated bottom b
and thence be forced to circulate upwardly through the mass of the material within ;
while the pipe J will discharge liquor into the upper end of the digesting vessel after
passing through the heating pipes in the upper heating apparatus D, when this liquor
will be sprayed down on the material below. The drawing indicates by arrows 1 the
direction of the draft of the liquor through pipe G to the pump; and by arrows 2 the
direction of circulation of the liquor is indicated, as passing from the pump through
pipe I, into the lower end of the digester from whence it is forced upwardly by the
pressure of the pump, through the pipes c of the lower heating device, then to be
discharged into the chamber below the perforated bottom 6 to pass upwardly through
the mass of material to the annular chainber E as indicated by arrows 3. Arrows 4
indicate the course of the passage of the liquor from the pump through pipe J, into
the pipe at the upper end of the digester from which it is discharged by the force of
the pump, after being heated by the heating device D as before described. Arrows 5
indicate the downward circulation of the liquor through the upper portion of the mass
of material, to the annular chamber E in which chamber this liquor will mingle with
the liquor circulated upwardly from below, the pump, through pipe J into the pipe
at the upper end of the digester, from which it is discharged by the force of the pump
after being heated by the heating device D as before described. Arrows 5 indicate
the downward circulation of the liquor through the upper portion of the mass of
material, to the annular chamber E in which chamber this liquor will mingle with
the liquor circulated upwardly from below, and be drawn, with the same again to the
pump, to be again forced into the digester to have a dual circulation through the
material in the same.
It should be understood that in the practise of this process it is not always necessary
that the digesting vessel contains within it, the liquor heating devices, as any suitable
liquor heating devices can be employed outside of the digester, and the liquor be
introduced and drawn from the same by means of suitable pumps, and forced into
the digester, with one portion entering the lower end thereof to circulate with a dual
circulation as above described.
It is also to be understood that the digesting vessel may be made with any suitable
form; and that one or more pumps can be used for effecting the dual circulation,
which is peculiar to this process.
The advantageous results obtained by this process are:
First. The mass of material to be treated, will be prevented from being packed down
on the perforated bottom, by reason of the upward circulation of the liquor opposing
the natural gravitation of the material toward said perforated bottom, thereby
preventing the packing of the former on the latter.
Second. By means of the dual circulation a less amount of liquor can be employed
than heretofore used in digesters for reduction of the same kinds of material.
Third. The vapours from the pitches, oils, gums and resins, natural with different
woods, plants and grasses, are permitted to rise above the liquor line, in the vessel and
become saponified, by the action of the alkaline liquor, while percolating downwardly
toward the said liquor line.
Fourth. The cooking liquor, being heated at each end of the digester before its
entrance into the mass of material from two directions, one from below and the other
from above, will carry with it the heat necessary to effect a uniform temperature of
the whole mass of material contained between the two ends of the digesting
chamber.
Fifth. By reason of the dual circulation, in this process, the cooking liquor is
made to carry with it the heat, to so uniformly cook all portions of the material, that
no part of the same will be either over-cooked or under-cooked.
Sixth. By this process all kinds of vegetable substances containing fibre, can be
successfully reduced by the use of a less volume of liquor than heretofore employed,
and this liquor be used with less strength, and the cooking be completed in less time
and under less pressure than heretofore required, so that the reduction of vegetable

page_text: materials under this process, will be effected more cheaply than heretofore, while the
product itself will be uniform in character and much stronger in fibre than those
fibres produced by the old processes from like material.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondent I declare that what I claim is
First. The process above described for treating vegetable substances for making
fibre or paper stock, the same consisting in subjecting vegetable materials, such as
woods, plants straws and grasses to the action of a highly heated chemical cooking
liquor within a steam-tight digesting vessel, in which one portion of the cooking liquor
will be circulated upwardly through the mass, to about the middle of length of the
same, and another portion be circulated downwardly, through the mass, to the same
point, substantially as described.
Second. The process, herein described, for reducing vegetable substances to fibre or
paper stock, the same consisting in massing the material within a steam-tight vessel
and forcing through this mass a highly heated chemical cooking liquor with a dual
circulation, in which one portion of the liquor will be circulated continuously upward,
through the lower half portion of the mass to about the middle of the same, while
another portion will be circulated downwardly, through the upper half portion sub-
stantially as described.
Third. The process, herein described, for converting vegetable substances into paper
stock or pulp, the same consisting in reducing vegetable substances to small pieces,
then introducing the same into a digesting vessel which is steam tight and subjecting
this mass of material to the action of the chemical cooking liquor which is circulated
continuously in two directions, with one portion being sprayed downwardly, on the
material below, to percolate through the same to about the middle of length of the
digesting chamber, and another portion circulating upwardly, through the lower
portion of the mass of material, and at the same time to the middle of the digesting
chamber, to mingle with the liquor from above, and then be drawn from the vessel to
be again reheated and made to circulate with a dual circulation continuously, as
described.
Fourth. The process, above described, for treating vegetable substances for reduction
of paper stock or fibre, the same consisting in confining within a steam-tight vessel,
the material to be reduced, then heating the cooking liquor to a degree sufficient to
dissolve the oils, gums and resins contained in the material, with one portion forced
upwardly through the lower half portion of the same, and another portion down-
wardly through the upper half portion, to be drawn together from the vessel and again
reheated and circulated, with this dual circulation continuously until the portions of
the material have become disintegrated, substantially as described.
Fifth. The process herein described, for treating vegetable substances for their
reduction into paper stock, the same consisting in submerging within a steam-tight
vessel, the lower half of the mass of the material and circulating the liquor upwardly
through the same, and saturating the upper half of the mass with the liquor by
circulating it downwardly, through the lower half of the same and applying heat
to the liquor sufficient to dissolve the gums, resins and oils and other soluble portions
of the material, while the liquor is being circulated with a dual circulation through the
same, substantially as above described.
Dated this 16th day of August 1888.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.