IMPROVEMENTS IN PROCESS FOR MAKING PAPER STOCK OR PULP
Year: 1886

page_text: "
I, JOHN DAVIS TOMPKINS of the Town of Nassau in the County of Rensselaer
and State of New York, U.S.A., Manufacturer, do hereby declare the nature of
iny invention for
IMPROVEMENTS IN PROCESS FOR MAKING PAPER STOCK OR
PULP" and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
My invention relates to an Improvement in process for the manufacture of Paper
Stock, or Pulp, from Wood, Straw, Grasses, or any other known substances, or
materials heretofore employed, without any waste of the essential fiber of the
material; and without any rehandling of the same after its first introduction into
the apparatus provided; and without the aid, or use of any other apparatus or
mechanism and power, other than the apparatus first receiving the material, and
the pumps and power for operating the same.
To carry my invention into effect, I provide an apparatus consisting of a digester
having oppositely located liquid-chambers which are each seperated from the
digesting chamber by a perforated wall, or diaphragm, a system of pipes, provided
each with proper valves, and pumps for the introduction and circulation of the
different treating waters and liquors through said chambers, and steam pipes, also
provided with suitable valves, whereby the different treating liquids and liquors
employed for cooking the material and disintegrating the fibers, and for bleaching
and washing the saine, will be successively circulated (in the respective times of
treatinent) through the material within the digesting chamber, in alternating
reversed directions, until each kind of liquid, or liquor, employed has acted
sufficiently on the respective portions of the material intended to be affected to the
extent required by each.
The prefered form of the apparatus I propose to employ, for the purpose of
carrying my new process into practice, is illustrated in the accompanying drawings,
n which:
Figure 1, is a sectional elevation of the apparatus, illustrating the digester and
he system of pipes and pumps employed; and Figure 2 is a plan view of the
ame.
In the drawings, A, represents the shell of the digester, and A', is the digesting-
hamber. B. B are oppositely located perforated walls, or diaphragms, which
eperate this digesting chamber from the liquid-chambers C. C₁ at the opposite
uds of shell A.
'

page_text: D, is a man-hole provided in the upper end of the digester, and is closed by
plate d, in the usual manner. D' is a discharge pipe, from the digester, and is
provided with a suitable valve d¹..
E. and F. are rotary force pumps of any suitable known kind, and are each con-
nected with a system of pipes, and are operated by any suitable power. Pump E,
is connected with the upper liquid-chamber, C, by means of draught-pipe e, and
with the lower liquid-chamber C. by discharge pipe e'; and pump F is connected
with lower liquid chamber C by draught pipe f. and with the upper liquid
chamber C, by discharge pipe f₁. These pipes are each provided with suitable
valves, and and respectively, which may be opened and clossed at will.
Connected with draught pipe e, are a series of supply pipes H, I, J, and K,
provided, each, with a suitable valve h. One of these pipes, as H, connects, from
a hot-water tank, to draught pipe c; another, as pipe I, connects, from a cold water
tank to the same draught-pipe e; and another as pipe J, connects, from an alkaline-
liquor tank to the same pipe e; and the other, K, connects from the bleaching-
liquor tank to the same pipe. By opening valve h of any one of the above
described pipes, and closing the valves of the others, and valve i of pipe e, and
opening valve ¹, of pipe e¹ the liquid, or liquor, to be employed, will be introduced
into the digesting chamber, through chamber C, from its corrosponding tank.
Connected with discharge-pipe f1 are a series of branch discharge pipes L,
M, and N, provided, each, with a suitable valve ¹ which is opened and closed at
will. One of these pipes, as pipe L, is for the discharge of hot water from the
digesting-chamber into a suitable tank; another, as pipe, M is, for the discharge of
the alkalin-liquor from the digesting chamber into a proper tank, prior to its
evaporation and burning of the residuum, for reclaiming the alkali; and the
other, pipe N, is for the discharge of the bleaching-liquor into any proper tank,
for its reuse in the subsiquent treatment of the other charges of material to
be made.
Pressure is exerted on the treating liquid, or liquor, with the material, within
the digesting chamber, by means of live steam pipo O, and its branches 0¹,
02, and 0. Connecting from any suitable steain generator, to the oppositely
located chambers C and C. These steam pipes are provided with suitable
valves n, n operated at will.
A pipe P, for leading the condensed steam to any suitable water, or other tank,
to be heated, is provided, and has suitable valves for regulating the discharges from
the same from upper liquid-chamber C¹.
A pipe Q, provided with a suitable valve, also connects from the upper end of
chamber C, to the bleaching-liquor receiving tank, for leading the chlorine gas,
or othe bleaching gas, to said tank for its re-use in treating other charges of
material.
A waste liquor discharge pipe G, provided with a suitable valve g is provided at
the lower side of chamber C, for the discharge of the waste liquor from the material
treated.
Connected with the digesting-chamber A at any suitable point, is a sample
tester T, of any suitable form of construction, by means of which samples of the
material being treated may be examined from time to time for determining the
progress of the operations.
The above described devices and elements are the essential parts of the apparatus
I propose to employ as being best suited for carrying my new process into effect.
It should be understood that the sizes and the proportions, and the situations of
the several pipes and pumps, in relation to each other and the vessel can be changed
as may be prefered for economy and most convienient for operations. And it should
also be understood that the perforations in the walls B, E seperating the respective
chambers C and C¹ from the digesting chamber A¹ should be small, and that they
may be little larger or smaller than one eighth of an inch, diameter, accordingly as
the nature of the material, whether, wood, straw, grasses or other substances to
be treated, may require. These perforations are countersunk on the sides of the

page_text: respective diaphragms facing the respective liquid-chambers C, C', so that the
smaller arears of these counter-sunk perforations will face towards the digesting-
chamber.
Having described my prefered form of apparatus, I will now proceed to describe
the several successive and progressive steps in my new process.
The material previously cut, or reduced to a uniform length, in particles, of about
from one to two inches, is introduced into the digesting chamber through man-
hole D; and while being introduced hot-water is showered down on the material
from the upper perforated diaphragm C¹, by means of pumps E and F operating for
drawing the hot-water from its tank through the pipes H, and e, and discharging
the same through pipe el, into chamber C, and from thence by pump F, drawing
through pipe f, and discharging the same through pipe f¹, into upper chamber C¹,-
the proper valves being opened, while all the others are closed. This simultanious
introduction and showering down of the material will be continued until the
digesting-chamber has been filled up to the top, or apex, of the perforated
diaphragm B¹.
The first step in this process will now be commenced. The water within the
digesting-chamber, with the material, will be heated to about boiling temper-
ture, and be so maintained for effecting the water cooking of the material,
while the water will be circulated through the mass in one direction, say, down-
ward, for from five to ten minutes more or less, when the circulation of the water
will be reversed to an opposite direction, upwards, for about the same length of
time, and then, again changed to a downward direction for about a like time, and
then to an upward direction, and so on, alternatily, in reversed directions with the
times of circulations, in each direction, about from five, to ten minutes, more or less,
according to the nature of the material being treated. This water cooking, under
reversed directions of circulation of the cooking water, will be continued from one
to three hours, inore or less, accordingly as the nature of the material will require,
for effecting a complete desolving of all the water-soluable portions of the acids,
gums and natural coloring matters in the lignire associated with the pure cellulose,
or fiber, in the material treated.
These alternate reversed circulations of the cooking water, through the mass
treated, will be effected, by operating, for a time, pump F, so that the water will bo
drawn from lower chamber C, through pipe f, and discharged into upper chamber C¹¹
through pipe f¹, when the circulation will be downward; this pump F will then
be stopped and pump E, will be operated to draw the water from upper chamber C¹,
through pipe e, and discharge the same into lower chamber C, through pipe e¹,
when the circulation of the cooking water will be in direction upward through the
mass of material, in the digesting-chamber; and by alternate operations of these
pumps E, and F, and their co-acting pipes, the circulations will be reversed from
time to time at will.
:
The second step in this process will now be had-the water cooking being
completed which consists in straining the cooking water, through the treated
mass of material, in an upward direction from the lower chamber C, so as to leave
the desolved portions of the lignire, neighboring the perforated diaphragm, at the
lower end of the digesting chamber, and below the lower portion of the mass, or
the main body of the material, that this desolved matter may be deposited near to
the waste discharge pipe, for its first discharge from the digester. This is effected
by operating pump E, to produce an upward circulation of the cooking water,―in
its entire volumn-at least once upward through the digesting chamber, when the
purer and more limped water will readily, strain through the mass, while the thick
substance, in with the water, will be stopped by the body of the undesolved
material and be lodged below, or below the main body portion of the same.
operator will now open vent V. and valve g of pipe G, when the thickened fluid
substance, consisting of the desolved matters and water, mixed, will be discharged
from chamber C, and the lower end of the digesting chamber, and be followed by
the more pure water, from above, which will run down through the mass and tota
The

page_text: degree wash out all the desolved matters that might have had lodgement in the
lowermost portion of the mass of treated material. When the matereal has been
drained from the cooking water, pipe G, will be closed.
The third step in this process will now be had. This consists in washing and
rennsing the resultant cooked material, free from all the desolved matters which
may have adhereance to the particles of the same, after the discharge of the
"cooking water.
This washing consists in circulating hot pure-water, through the mass of water
cooked material, in reversed directions, alternately upward and downward, for a
'fiew minutes in each direction, and until the material has washed from it all the
desolved matters and coloring matters. One or more charges of this hot pure
water may be circulated through the material in reversed directions to complete
the washing and rennsing of the same.
This washing water will be introduced and circulated by means of pumps E
and F and their respective co-acting pipes, operated alternately, as described for
introducing and circulating the cooking water in reversed directions.
The fourth step in this process will now be had, after the washing water has
been drained from the material. And it consists in circulating, through the
washed water-cooked material, alkaline-cooking liquor, under pressure of steam, in
reversed directions, alternatly downward and upward. These circulations are
made in each direction, for from ten to thirty minutes, by operating pumps E
and F and their co-acting pipes alternately, and substantially in the same manner
as when the cooking water is circulated through the material, in the first step in
this process. This cooking of the water cooked material with reversed circulations
of the alkaline liquor will be continued for from two to five hours accordingly as
may be required by reason of the nature of the material treated, and until the
alkali liquor has desolved all the lignine remaining associated with the pure
cellulose, or fiber, after the water cooking, and the material has been fully
disintegrated and reduced to fine fiber.
The fifth step in this process, consisting in seperating the desolved and thicker
matters from the spent alkaline liquor, and depositing the same at the lower side
of the mass of reduced fiber, will now be proceeded with. This is done by
circulating the liquor upwardly (by means of pump E. and its pipes e. e¹) for about
twenty minutes, more or less, before the liquor is discharged from the digesting
chamber. In this upward circulation, the liquor will first carry the fiber up
against the upper perforated wall B¹, and to a degree pack the same, sufficiently,
to serve as a strainer, when the fiber will permit the ready passage of the thiner
portion of the liquor while it will prevent the desolved thickening substances, with
the liquor, from having a ready passage through the same, so that these desolved
substances will, in their greatest portion, become lodged at the lower side of the
mass, and in situation for being readily discharged from the digesting chamber
without the least liability of becoming mixed with the reduced fiber. When this
seperation and deposit of the thicker desolved substances is made as above
described, the circulation will be stoped and the liquor will be discharged from the
digesting chamber through pipe G, and be carried by any proper conductor to a
suitable tank, preparatory to its being evaporated, and the alkali therein reclaimed,
for reuse, by burning the residuum, as has heretofore been practiced,
The operator will now proced with the sixth step in this process, which consists
of washing and rennsing from the reduced fiber all traces of alkali. This will be
effected by circulating hot pure water, in reversed directions, alternatly upwardly
and downwardly through the mass of fiber substantially the same as in the washing
of the water cooked material; the water being introduced and circulated by means
of pump E and pipes e e¹ as befor described, in the first washing by, being
circulated for a few minutes, in each direction, for about thirty minutes, in the
aggregate, when the water will be discharged, and replaced by a charge of fresh
pure hot water for a second washing and rennsing by reversed directions of
.circulation of the same through the mass of fiber. When all traces of alkali has

page_text: been washed from the disintegrated fiber, the water will be discharged and drained
from the same, through pipe G.
The seventh step in this process will now be had, which consists in introducing
into the digesting chamber a suitable bleaching liquor, preferably, chlorine liquor,
and circulating the same through the clean pure fiber in reversed directions,
alternatly upwards and downwards, for, from one to three hours as may be
required for bleaching the fiber to the extent required. Each of these reversed
circulations will be continued for, from ten to twenty minutes, more or less. This
treatment can be had either with, or without pressure of steam, as may be prefered,
or as the nature of the fiber may require. When the bleaching has been completed
the circulation of the liquor will be stoped, and live steam will be introduced into
the digesting chamber from below, and the valve of chlorine gas pipe Q will bo
opened, when the chlorine gas, or other bleaching gas, will be driven out from the
digesting chamber and be discharged into the tank, containing water, or chlorine,
or bleaching liquor, and be there preserved for reuse for treatment of other charges
of reduced fiber. The chlorine, or bleaching liquor, will now be discharged from
the digesting chamber, by means of pump F and pipes f, f¹, and pipe K into a
suitible tank to be there held for subsiquent reuse.
The eighth step in this process will now be had. This consists of washing and
rennsing the bleached reduced fiber, for the removal of all trace of the bleaching
materiel. This is effected by filling the digesting chamber with pure water-hot,
or warm, in the first washing, and circulating the same in reversed directions,
alternately upwards and downwards for a few minutes in each direction, for about
thirty minutes in the aggregate, when this charge of washing water will be replaced
by another charge of. pure water which will also be circulated alternately upwards
and downwards through the fiber the same as before. A third washing can be had
in the same manner, if prefered, so that no trace of chlorine will be left in the
bleached fiber.
The bleached product will now be discharged through discharge pipe D' into
any suitable tank, or vessel, preparatory to its being converted into paper; or pre-
paratory to its being made into sheets and dried as sheet pulp, or preparatry to
being dried in the form of kernels, or otherwise. Or this product can be colored
while within the digesting chamber, before its discharge, by circulating colored
liquor through the mass, in reversed directions, as are the other liquors, as before
described.
In the water-cooking part of this process, the reversed circulations of the
cooking water through the mass of raw material prevents any portions of the
material from becoming compacted, or matted together, as eich direction of circu-
lation of the water will be reverse to that of the preceeding, and the water will,
when moving in one direction, carry, or move the particles of fiber in an opposite
direction from that it before moved in, so that all liability of packing or matting.
the material will be removed, and thereby, the particles be in best situation and
condition of exposure to the action of the circulating water, so that each particle
in the whole inass will be effected simultaniously and uniformly the same as all
the other particles, and the entire mass of material will be uniformly acted on in
all its portions without any one portion being overcooked or under-cooked, as in the
old processes of cooking in open tubs, or in closed digesters with the cooking water
circulated continiously downwardly, or in digesters which are rotated, as under all
these old processes the particles of material are not changed in their situations in
relation to each other, while some portions are not submerged, but float on the
surface of the water, and other portions are compacted, so that the cooking water
will not readily circulate through the same. By this process of cooking the raw
material with water about boiling, instead under pressure, none of the coloring
matter, natural in the material, will become cooked into the cellulose, or fiber,
which is of great advantage, as the final product will not require to be so long
treated with the leaching liquor, and that liquor will not be required to be made
with the strength it would, was the coloring matter cooked into the fiber, Another

page_text: advantage is, by this water cooking, from (30) thirty to (50) fifty per-cent of the
lignine, associated with the cellulose, will be disolved, and seperated from the pure
cellulose or fiber, and thereby leave less amount to be desolved in the subsiquent
alkaline cooking, and also leave the undesolved portions in the best condition for
such subsiquent cooking. And with the fiber partly disintegrated, so that the alkali-
liquor will not be required to be used with the degree of strength, as heretofore, while
the complete desolving of the gums, acids and other portions of the lignine will
be affected in a much shorter time than when this water cooking is dispensed with,
as in some of the older processes.
It will be understood that after the material has been treated to the water
cooking operation above described, and the desolved portions have been removed,
the bulk of the mass of material will be greatly lessened, and will not fill the
digesting chamber to the extent as did the raw material, first introduced; and
consequently there will be less material in the digester to be acted on by the
alkaline liquor; while at the same time the material will have more room in which
to move when the circulating liquor is operating with the particles composing the
mass. By the reversed circulations of the alkaline liquor all the particles of the
partly disolved and disintegrated material will be in constant state of movement,
and fully submerged throughout all the cooking; and the liquor, in its strength,
will be brought in active contact with every particle of the material and be made
to act simultaniously and uniformly on all the particles, and begin and complete
the disolving of the soluable portions of the lignine and disintegration of the
cellulose, uniformly, the same, in all the particles, so that no portion will remain
uncooked when other portions are cooked, and no portion will be over-cooked when
the cooking of the other portions is properly completed.
In the old processes of alkaline cooking, the material was more or less compacted
in some of the portions of its mass, while other portions were loose and floating on
the upper surface of the liquor, and, both, the compacted and floating portions
were less effectively acted on by the liquor than those other portions which were
between these more compact and loose and floating portions, and consequently
the intermediate portions of the mass would become properly cooked long before
the compacted and floating portions, and before the latter would be properly cooked,
these intermediate portions would be overcooked at the expense of a considerable
loss of fiber or stock, or a deterioation of the same, or would necescitate the transfer
of the stock from the digester, before all its portions were reduced, and a seiveing
of the same for seperating the uncooked portions from the cooked and disintegrated
portions, that the former might be again subjected to second cooking, or to the
action of a beating machine, or be thrown away. These disadvantagious results,
together with the greater strength of the liquor employed and the great length of
time required for treatment, in the old processes, are all obviated by my-improved
process of alkali-cooking, in which by the reversed circulations of a weaker alkaline
liquor, for a shorter time, is made to seperate all the lignine from the pure cellulose
and reduce the material treated to finely disintegrated fiber or paper stock.
In the old processes, the substances disolved, in the process of the cooking of
the material, were always left mixed in with the disintegrated and partly
disintegrated fiber after the cooking, and hence necessitated the transfer of the
mixed mass to other apparatuses or machines for a complete removal of these
desolved substances. All this is obviated by that part of this process, in which,
the upward circulation of the cooking-water, or liquors, through the material,
operates to prevent such mixing, and to deposit these disolved substances in the
lower portion of the digester, and below the lower portion of the treated mass, 80
as to be readily discharged from the digester and first run off, to be followed by
the purer water or clearer liquor from above, for washing down whatever disolved
matters which may be left adhereing to the particles in the lower portion of the
mass, so that in the subsiquent washings and rennsings there will be required
a less amount of water and less time to perfectly cleanse the fiber from all desolved
substances.

page_text: By washing the respective resultant product from each prior treatment, by
circulating pure water in reversed directions through the body of the same while
within the digesting chamber, I dispense with the expense and use of washing
engines and apparatuses, and the labor and expense of transfers of the material, and
by the use of less water in a far shorter time, effect a full and uniform removal of
all the desolved substances and all traces of the chemicals employed in the former
treatments.
In this process of circulating the bleaching liquor in reversed directions through
the body of the cleansed and pure fiber, or stock, within the digesting chamber,
I am enabled, properly and rapidly, to bleach the same to the degree prefered, or
fully bleach the same in the short time of a few hours, and thereby dispense with
the use of spiceal bleaching apparatuses, and the labor and expense, heretofore
attending the transfer, handling and operations with the fiber, and am enabled
with a bleaching liquor of less strength to uniformly bleach all the particles of the
stock, or pulp, in a much less time than heretofore required, for the reason, that,
evry particle of fiber will be submerged and enveloped by the bleaching liquor
while it is being circulated between the particles, and the bleaching agent, having
affinity for the water, will be quickly and positively carried into the body of each
fiber, and act interiorally as well as exteriorally on the same, simultaniously with
all the other particles.
3
When the respective treatments, of the material, are in progress, the operator,
or attendant, will by taking samples of the material, from time to time from the
digesting chamber, through tester T, observe the progress of each treatment, and
assertain by proper examination of each sample, the condition of the material
being treated, and when the operations have progressed to completion in each step.
It should be understood, that, if in lieu of alkalies, sulphides, or acids, are
employed for reducing and disintergrating the material, that liquors of these
substitutes will be circulated in alternating reversed directions, through the mass
of material in substantially the same manner and under like conditions as is the
alkaline liquor.
Although with most materials, the water cooking of the same, as above
described, is employed by mo because of the advantageous preparatory results
obtained before the alkaline treatement, yet in some cases, as when but a small
per-cent of the gums and other substances will be readily desolved by the water
cooking, I would dispense with the latter and subject such material, at first
instance, to the action of the alkaline liquor, or known equivilent disintergrating
and reducing liquor, under pressure, and high. temperature, and by circulation of
the same in alternating reversed directions; and would follow this treatment' with
the several other successive treatments in the order substantially as above described
as following the alkaline cooking.
I employ alkaline liquor made from either potash, soda, or any other kind of
alkali heretofore employed, and use it with a strength proportionate to the amount
of silica and other substances, natural in the material to be desolved, which can
be assertained by chemical analysis; and I determine the kind of alkali. I would
use for the liquor, by assertaining in the same analysis the kind and per-cent of
alkali wether potash, or soda, natural to and contained in the particular kind
of material to be reduced to pulp, and use that kind which, in character, is the
same as that of greatest percent found in the material, so that the kind of alkali
naturally in the material will not react against the kind in the treating liquor,
but will, on the contrary, contribute to maintain the strength of the latter and
thereby keep it effective in its operations.
When acids are employed, the interior surfaces of the digester should be lined
with some substance which will not be effected by the acids employed.
The resultant product from this process will be a finely disintegrated fiber,
which will be free from brittleness and be adapted for making strong paper of the
best quality for either printing or writing on, or other purposes.

page_text: Having now particularly described and assertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In the manufacture of paper stock, or pulp, the process of treating wood,
straw, grasses, or other vegetable substances to the action of pure water, at
about boiling temperature, circulated through the mass of material, within a
digesting chainber, in alternating reversed directions, substantially as described.
2. In the manufacture of paper stock or pulp from vegetable substances, or
materials, the process of seperating the desolved portions from the undisolved
portions of the said material, above described, the same consisting of circulating
the cooking water, or other liquors with which the material has been treated, in
an upwardly direction through the mass, or in a direction which will be away
from the discharge opening of the digesting chamber, substantially as described.
3. In the manufacture of paper stock, or pulp, from vegetable substances or
materials, the process of treating the material to the action of alkaline, or equivilent
disintegrating and desolving liquor, at high temperture and under pressure, with
said liquor circulated through the mass of material in alternating reversed directions,
substantially as above described.
4. In the manufacture of paper stock, or pulp, from vegetable substances or
materials, the process of cleansing the material from all the disolved substances,
or chemicals, or both, left with it from its prior treatment, the same consisting of
circulating pure water in alternating reversed directions through the mass of
material within the chamber, substantially as above described.
5. In the manufacture of paper stock, pulp, or fiber the process of bleaching
the same, consisting in treating the stock, pulp, or fiber, to the action of a
bleaching liquor, circulated through the mass in alternating reversed directions,
substantially as above described.
6. The process of reducing vegetable substances, or materials, consisting in first
cooking the same in pure water, at about boiling temperture, which is circulated
in alternating reversed directions through the material until the water soluable
portions are desolved, then treating the merteriel to pure water which is circulated
alternately in reversed direction for removal of the desolved substances, and then
subjecting the resultant product of the water-cooking to the action of an alkaline,
or other known equivilent disolving or disintegrating liquor, at high temperture
and under pressure, and circulated in alternating reversed directions through the
treated mass, substantially as above described.
7. In the manufacture of paper pulp or stock the continious process for treating
wood, straw, grasses, or other vegetable substances, or materials, above described,
the same consisting in the several progressive steps of treatment of the material by
water, alkaline, or equivilent liquor, and bleaching liquor, which are respectively
circulated with alterneting reversed directions, through the body of the treated
material, in the order and under the respective conditions substantially as above
set forth.