MODERN PAPER-MAKING
♦The modern mill♦
Though the steady march of progress and invention has given to the
modern paper-maker marvelous machines by which the output is increased
a thousand-fold over that of the old, slow methods, he still has many
of the same difficulties to overcome that confronted his predecessor.
While the use of wood pulp has greatly changed the conditions as
regards the cheaper grades of this staple, the ragman is to-day
almost as important to the manufacturer of the higher grades as he
was one hundred years ago, when the saving of rags was inculcated as
a domestic virtue and a patriotic duty. Methods have changed, but the
material remains the same. In a complete modern mill, making writing
and other high-grade papers, the process begins with unsightly rags as
the material from which to form the white sheets that are to receive
upon their spotless polished surface the thoughts of philosophers
and statesmen, the tender messages of affection, the counsels and
admonitions of ministers, the decisions of grave and learned judges,
and all the
“Wisdom of things, mysterious, divine,” that
“Illustriously doth on paper shine,”
as was duly set forth in rhyme by the “Boston News Letter” in 1769.
“The bell cart will go through Boston about the end of next month,”
it announced, and appealed to the inhabitants of that modern seat of
learning and philosophy to save their rags for the occasion, and thus
encourage the industry.
♦The methods of to-day♦
The rags do not come to the mammoth factories of to-day in “bell
carts,” but by the carload, in huge bales, gathered from all sections
of this great Republic, as well as from lands beyond the eastern and
the western oceans. The square, compact, steam-compressed bundles are
carried by elevators well up toward the top of the building, where
they await the knife of the “opener.” When they have been opened,
the “feeder” throws the contents by armfuls into the “thrasher.” The
novice or layman, ignorant of the state in which rags come to the
mill, will find their condition a most unpleasant surprise, especially
disagreeable to his olfactory nerves. Yet the unsavory revelation
comes with more force a little farther on, in the “assorting-room.”
♦The thrasher♦ The “thrasher” is a great cylindrical receptacle,
revolving rapidly, which is supplied with long wooden beaters or arms,
passing through a wooden cylinder, and driven by power. ♦The sorting
room♦ When the rags have been tossed in, there ensues a great pounding
and thrashing, and the dust is carried off in suction air-tubes, while
the whipped rags are discharged and carried to the “sorting” and
“shredding” room. Here the rags are assorted as to size, condition,
and the presence of buttons, hooks and eyes, or other material that
must be removed. Then those that need further attention are passed on
to the “shredders,” these as well as the “sorters” being women. The
“shredders” stand along a narrow counter; in front of each one there
is fastened a long scythe-blade, with its back toward the operator and
its point extending upward, the shank being firmly fixed to the table
or operating board. Here buttons, hard seams, and all similar intruders
are disposed of, and the larger pieces of rags are cut into numerous
small ones on the scythe-blades. The rags thus prepared are tossed by
the women into receptacles in the tables. The work in this room is
the most disagreeable and unwholesome of any in the entire process of
manufacture, and this despite the fact that these rags, too, have been
thrashed, and freed from an amount of dust and dirt beyond ordinary
belief.
♦The higher grades♦
While watching the operations carried on here, it is impossible to
repress the wish that rags might be bought otherwise than by the pound,
for, unfortunately, filth, dust, and dirt weigh, and to wash rags only
reduces the weight. While this is a true reflection of the condition in
the average mill, it is pleasant to know, however, there are others of
the higher class that are decided exceptions, as far as dust and dirt
are concerned. Such are the mills making high-grade ledger and bond
papers, as well as the mill manufacturing the paper that is used for
the printing of our “greenbacks,” to which further reference will be
made later. In these exceptional mills everything is neat and perfectly
clean, all the stock used being new and fresh from the cotton or linen
mills, or from factories producing cloth goods, like shirt and corset
factories, and others of the same sort. The sorting and shredding room
is always large and light, with windows on all sides, and is well
ventilated, offering a decided contrast in many respects to the less
cleanly mills first referred to, where the women must wear bonnets or
hoods for the protection of the hair. In either case the process is
certainly an improvement over the old plan of leaving the rags to decay
in a cellar to expedite the removal of the glutinous matter.
♦The cutter♦
From the “sorting” and “shredding” room the rags are conveyed to the
“cutter,” where they are cut and chopped by revolving knives, leaving
them in small pieces and much freer from dust and grit. Various
ingenious devices are employed for removing metal and other hard and
injurious matter, magnetic brushes serving this purpose in some mills.
♦The devil♦ When the “cutter” has finished its work, the still very
dirty rags go for a further cleansing to the “devil,” or “whipper,”
a hollow cone with spikes projecting within, against which work the
spikes of a drum, dashing the rags about at great speed. Human lives
are often freed of their baser elements and restored to purity and
beauty through the chastening influences of tribulation or adversity;
in like manner the “whipper” carries the rags forward a step in the
process of purification that is necessary before they can be brought to
their highest usefulness. But the cleansing process, which is only a
preparation for what is to follow, does not end with the “whipper,” the
latter having served merely to loosen, not to dislodge, a great deal
of dust and dirt. ♦The duster♦ The final operation in the preliminary
cleaning is performed by the “duster” proper, which is a conical
revolving sieve. As the mass of rags is tossed and shaken about the
loosened dust is carried away by the suction of the air, which draws
the dust particles into tubes furnished with suction fans. In most
modern mills the rags are carried forward from the “duster” on an
endless belt, and a careful watch is kept upon them as they emerge to
detect the presence of unchopped pieces, buttons, or other foreign
substances. The journey of the rags over this endless belt or conveyor
terminates in a receiving-room, in the floor of which there are several
openings, and immediately below these the mouths of the “digesters,”
which are in a room beneath. ♦The digester♦ The “digesters,” as they
are suggestively and appropriately termed, are huge revolving boilers,
usually upright, which often have as great a diameter as eight feet,
with a height of twenty-two feet, and whose digestive capacity is
upward of five tons of rags each. ♦Cooking of rags♦ The rags that are
to be “cooked” are fed into the “digesters” through the openings in the
floor, and the great movable manhole plates are then put in place and
closed, hermetically sealing the openings or mouths through which the
boilers have been fed, these having first been charged with a mixed
solution of lime and soda, and with live hot steam in lieu of gastric
juice as a digesting fluid and force. In some mills the boilers are
placed in a horizontal position, while in others they are in the form
of a large ball or globe, in either case being operated in the manner
described; those of upright form, however, are most commonly in use.
The rags are boiled under steam pressure of about forty pounds to the
square inch, and the cooking is continued from twelve to fourteen hours.
[Illustration: THE MODERN FOURDRINIER MACHINE--PAGE 73]
♦The washers or Hollanders♦
It is here that the process of cleaning begins in earnest; and as the
mass of rags is tumbled about in its scalding bath of steam-heated
lime-water, or “milk of lime,” the coloring and glutinous matters,
as well as all other impurities, are loosened from the fibers, which
are in the end so cleansed and purified as to come forth unstained
and of virgin purity. Having been sufficiently boiled and digested,
the mushy material, still looking dark and forbidding, is emptied
onto the floor below or into receptacles placed directly beneath the
boilers, where the color and dirt are allowed to drain off. The mass
is then conveyed to the “washers,” great tub-like receptacles, which
are shown among the illustrations, and which are known as “Hollanders,”
from the fact that these rag engines were invented in Holland, about
the year 1750 A. D. They are oval-shaped tubs, about twenty feet long,
nine feet wide, and three feet high, varying somewhat according to
the conditions. Each tub is divided for two-thirds of its length by
an upright partition, or “mid-feather,” as it is called, which makes
a narrow course around the vat. On one side of the partition the tub
is raised in a half-circle, close to which revolves an iron roll about
three or four feet in diameter, and covered with knives; in the bottom
of the tub, and directly under the revolving roll, is another set of
knives called a “bed-plate,” which is stationary, and against which the
roll can be lowered. But not to anticipate. When the emptyings from
the boiler have been thrown into the “washer” a continuous stream of
water is turned in at one end, the knife-roll having been adjusted so
as to open up the rags as they are set in motion. These then begin a
lively chase around the edge of the vat, through the racecourse formed
by the “mid-feather,” and under the rag-opening knives, where the water
is given a chance to wash out all impurities; then on up the incline
over the “back fall,” so-called from the elevation in the tub. A
cylinder of wire cloth, partly immersed in the moving mass, holds back
the now rapidly whitening fibers, while the dirty water escapes into
buckets inside the wire cloth drum, and is discharged into and through
an escape-spout. The heavy particles of dirt settle into what is termed
a “sand-trap” at the bottom of the tub.
♦Bleaching material♦
As the water clears, the roll is lowered closer and closer to the
bottom of the bed-plate, in order to open up the fibers more thoroughly
for the free circulation of the water among them. When the several
agencies of the “washer” have accomplished their purpose, and the
water runs clear and unsullied, a bleaching material is put into the
mass, which in the course of from two to six hours becomes as white as
milk. The dirty offscourings of all ragdom, first seen in the original
bales, and gathered from the four quarters of the globe, have endured
many buffetings, many bruisings and tribulations, and having been
washed come forth pure, sweet, and clean. From the washers the rags
are precipitated through a trap into drainers, which are chambers made
of stone and brick, with a false bottom, through which the water is
allowed to drain. This rag pulp, now called half stock, is kept in this
receptacle until the water and liquor are thoroughly drained off, when
it becomes a white and compact mass of fibers.
♦The drainers♦
The rags should stand in the drainers for at least one week, though
better results are obtained if they are left for a period two or
three times as long, as the fibers become more subdued. The process
of paper-making, as it has already been described, applies more
particularly to papers made from rags. To-day a very large proportion
of the cheaper papers are made from wood, either entirely or in part,
and these wood-made papers are subjected to a different treatment, to
which further reference will be made in this chapter.
♦The beaters♦
From the drainer the mass is carted to the beating engine, or “beater,”
which is very similar in construction to the washer just described. The
knives on the roll in the beater are grouped three together instead
of two, and are placed nearer the bottom or bed-plate in order to
separate more thoroughly the fibers. In the beater are performed many
and varying manipulations, designed not only to secure a more perfect
product, but also to produce different varieties of paper. It is the
theory of the beating process that the fibers are not cut, but are
drawn out to their utmost extent. In watching the operations of the
“beater,” one notices on the surface of the slowly revolving mass of
fibers, floating bluing, such as the thrifty housewife uses to whiten
fine fabrics. This familiar agency of the laundry is introduced into
the solution of fibers with the same end in view that is sought in the
washtub--to give the clear white color that is so desirable. Many of
the inventions and discoveries by which the world has profited largely
have been due primarily to some fortunate accident, and according to
a pretty story upon which paper-makers have set the seal of their
belief for more than one hundred and fifty years, the use of bluing
was brought about in the same way. ♦The bluing story♦ About the year
1746, so runs the story, a Mrs. Buttonshaw, the wife of an English
paper-maker, accidentally dropped into a tub of pulp the bag of bluing,
or its contents, which she was about to use in a washing of fine
linen. Frightened at what she had done, and considering it the part
of wisdom to keep silence, she discreetly held her peace and awaited
results. But when her husband had expressed great wonder and admiration
over the paper made from that particular pulp, and had sold it in
London at an advance of several shillings over the price of his other
paper, which had not met with any such accident, she realized that the
time for silence had passed. Her account of the happy accident led her
grateful husband to purchase a costly scarlet cloak for her on his next
visit to London town. This accident brought about another result which
was to prove of inestimable value to the future paper-maker--the use of
bluing in paper when especial whiteness is desired.
♦Engine-sizing♦
Important as the bluing or coloring is, however, it is only one of the
numerous operations or manipulations that take place in the beater.
Many of these, such as engine-sizing and body-coloring, require skill
and constant watchfulness. Here, too, if anywhere, adulteration takes
place. It is sometimes necessary to secure a fine-appearing paper
at small cost, and it is profitable to add to its weight. In such
cases, a process of “loading” takes place here, and clay or cheap,
heavy fibers are added. Clay is of value not only to increase the
weight, but also to render the paper more opaque, so as to prevent
type or illustrations from showing through, while at the same time it
makes possible a smoother surface by filling the pores in the paper.
But while it adds to the weight, clay must, of necessity, weaken the
paper. In engine-sizing, which is done in the beater, the size is
thoroughly incorporated with the fibers as these revolve or flow around
the engine. This sizing renders the paper more nearly impervious to
moisture. The difference between a paper that is sized, and that has
a repellent surface which prevents the ink from settling into it when
it is written upon, and an ordinary blotting-paper with its absorbent
surface, is due entirely to the fact that the former is most carefully
treated with sizing, both in the beating engine and in the size tub
or vat referred to later, whereas in the latter paper it is omitted.
♦Body-coloring♦ If the paper is to be tinted or body-colored, colors
made from aniline are generally used. Only in the highest grade of
writing-paper, and in some few papers that demand colors fast to the
light, is any other order of coloring matter employed. As may be
easily imagined, considerable skill is required to secure exactly the
desired tint, and to get the coloring matter so evenly mixed that each
small fiber shall receive its proper tint, thus insuring that the paper
when finished shall be of uniform color and not present a mottled
appearance.
♦Machine for making continuous web♦
When the operations of the beating engine have been completed, a most
interesting process begins, which marks a vast advance over the earlier
method of forming the sheets of paper with mold and deckel, straining
off the water, and shaking the frame with a quick motion to mat the
fibers together. The patient striving toward something better, which
has marked all the centuries since man first learned to carve his
rude records, finds its consummation in the process of making paper
in a continuous web. This result is accomplished by a machine first
invented by Louis Robert, a workman in a mill at Enonnes, France, who
obtained a French patent, with a bounty of eight thousand francs for
its development. This he later sold to M. Didot, the proprietor of the
mill, and the latter crossed the Channel into England, where, with the
aid of a skilled mechanic, the machine was in a measure perfected,
and then sold to Henry and Sealy Fourdrinier. They, with the further
aid of Bryan Donkin, their employe and expert engineer, made many
additional improvements, and sunk in the enterprise some sixty thousand
pounds sterling, for which their only reward was blighted hopes and
embittered lives. In 1847 the London “Times” made a fruitless appeal
on behalf of the surviving brother, who was eighty years of age,
and in great poverty. It is seldom that the world voluntarily makes
return to those who have bestowed upon it great material or moral
benefits, though it is ever ready to expend its treasure for engines
of destruction, and to magnify and reward those who have been most
successful in destroying human life.
♦First machine mill♦
The first “machine” mill was started at Frogmore, Hertz, England, in
1803, which was the year of the great Louisiana Purchase by the United
States, and it is not difficult to say which event has been productive
of the greater and more beneficial results to this nation. Through this
invention and its improvements the modern newspaper and magazine, with
their tens and hundreds of thousands of copies daily, have been made
possible, and men of all classes have been brought in touch with the
best thought of the day. Whatever makes for greater intelligence and
enlightenment throughout a nation makes for the greater stability of
the national life, and gives new emphasis to Bulwer’s words:
“Take away the sword;
States can be saved without it--bring the pen.”
♦The power of the pen♦
If to-day the power of the pen over the sword is greater than
it has ever been before, its increased and increasing influence
must be credited in large measure to the inventive genius and the
public-spirited enterprise that has made possible the great output
of our modern paper-mills. So thoroughly did these forces do their
work in the beginning, that in the century that has elapsed since the
Fourdrinier brothers sacrificed themselves and their means in the
perfecting of their machine, there have been really no changes in the
fundamental principle. Those that have been made have been in the
nature of further development and improvement, such as increasing the
speed and widening the web, thereby multiplying the product many fold.
[Illustration: THE FIRST PRESS ROLLS--PAGE 75]
♦The Jordan engine♦
But to resume the interesting journey of the rags, which had reached
a state of purification and perfection as pulp, and which we left in
the beaters. In some grades of paper the perfected and prepared
pulp is taken from the beaters and passed through what is known as a
“refining” or “Jordan” engine; this for the purpose of more thoroughly
separating the fibers and reducing them to extreme fineness. The
refining engines, are, however, used only in the manufacture of certain
grades of paper. ♦The stuff chest♦ The pulp is next taken from the
beater or refining engine, as the case may be, to what is called a
“stuff-chest,” an inclosed vat partly filled with water, in which a
contrivance for shaking and shifting, properly called an “agitator,”
keeps the fibers in suspension.
♦The screen♦
From the stuff-chest the mixture is pumped into what is known as
the “mixing” or “regulating” box. Here the stream first passes
over the “sand-tables” in a continuous flow. These are composed of
little troughs with cross-pieces, and are covered at the bottom with
long-haired felt, to catch any sand or dirt that may still adhere after
the numerous operations to which the pulp has been subjected. The flow
is then forced through the “screen,” which is a horizontal piece of
metal pierced with slots. For very fine paper, these slots are so small
as to be only one one-hundredth of an inch in width. They are usually
about a quarter of an inch apart. Through these tiny apertures the
fibers must find their way, leaving behind in their difficult passage
all lumps, dirt, or knotted fibers which would mar the perfection of
the product toward which they are tending. A vibrating motion is given
to the screen as the flow passes over it, or revolving strainers may be
used.
♦The flow onto machine♦
When the screen has finished its work, the water carrying the pulp in
solution flows in an even stream, whose volume varies according to the
width of the web of paper to be produced, through a discharge-cock
onto the Fourdrinier or cylinder machine, as the case may be, each of
which will be duly described. This stream has a filmy appearance, and
is of diverse color, depending upon the shade of paper to be produced.
From its consistency, which is about that of milk, it is difficult to
imagine that it floats separate particles of fiber in such quantities
as, when gathered on the wire cloth and passed to a felt blanket and
then pressed between rollers, to form in a second of time a broad web
of embryo paper sufficiently strong and firm to take definite form.
Man’s mastery of the process by which this startling and wonderful
change is effected has come as one of the rewards of his long and
patient study.
The Fourdrinier machine, which preserves at least the name of the
enterprising developers of the invention, takes up the work that was
formerly done by the molder. The wire cloth upon which the fibers
are discharged as described is an endless belt, the full width of
the paper machine. Upon this the fibers spread out evenly, being
aided by a fan-shaped rubber or oil cloth, which delivers the smooth
stream under a gate regulated to insure perfect evenness and to fix
uniformly the fibers of the web now commencing its final formation.
♦Deckel-straps♦ Deckel-straps of india-rubber are fastened on both
sides of the wire screen, and move with it, thus holding the watery
pulp in place. The deckel-straps are adjustable, and fix or regulate
the width of the paper. These and the gate, or “slicer,” are attached
to what is termed the deckel-frame, which corresponds to the deckel
used by paper-makers in the days when the manufacture was carried on by
hand. ♦Endless wire cloth♦ As the stream flows onto the endless belt
of wire cloth, the water which has borne the fibers filters into the
trough beneath. Being charged with very fine fibers, size, coloring
matter, and other similar ingredients, it is carried back into the
pulp-chest, to save these materials, as well as to contribute again
to the extra supply of water needed. ♦The save-all♦ For this reason
the trough into which it falls from the revolving “wire” is called the
“save-all.” A shaking motion is imparted to the “wire” from the frame
upon which rest the rolls that keep it in its never-ending round. This
aids in draining away the water, and mats or interlaces the fibers
together. At the end of the “save-all,” where the fibers are to leave
the “wire” for the next stage of their journey, suction-boxes are
placed, provided with an air-pump to take up the surplus water that
has not yet found its way through the meshes. ♦The dandy roll♦ Between
these suction-boxes above the wire is a wire-covered roll, which
impresses the newly formed sheet; this impression cylinder is called a
“dandy roll,” and it is from this that the web receives the markings
or impressions that characterize different papers. All watermarks,
patterns, and designs which it is desired to have appear in the paper
are put upon this roll, and here impressed upon the soft sheet, which
is clarified and left transparent at the points of contact. Thus the
impression is permanently fixed in the fiber, so that it can be
seen at any time by holding the sheet to the light. The power of
suggestiveness is a quality which is highly esteemed wherever it is
found, and which frequently furnishes a standard of judgment. Judged
by such a criterion, the impression cylinder, or “dandy roll,” has an
added value, for in all probability its operation suggested the idea of
printing from cylinders, as in our present web or perfecting presses.
♦The press-rolls♦
The matted pulp, now having sufficient body, passes on between two
rolls covered with felt, which deliver the web of damp paper upon an
endless belt of moist felt, while the “wire” passes under and back to
continue a fresh supply. The paper is as yet too fragile to travel
alone, and the web felt carries it between two metal rolls called the
first press-rolls. These squeeze out more water, give a greater degree
of compactness to the fibers, smooth the upper surface, and finally
deliver the web of paper to a second felt apron, which carries it
under and to the back of the second press-rolls. In this way the under
surface comes to the top, and is in its turn subjected to the smoothing
process. A delicate scraper or blade, the length of the press-rolls,
is so placed on each roll that should the endless web from any cause
be broken, the blade may operate with sufficient force to prevent the
wet paper from clinging to the rolls and winding about them. From this
point the paper travels alone, having become firm and strong enough
to sustain its own weight; passing above the second press-rolls, it
resumes its onward journey around the drying cylinders, passing over
and under and over and under. ♦The dryers♦ The drying cylinders are
hollow and heated by steam, their temperature being regulated according
to requirements. These driers, made from iron or steel, are usually
from three to four feet in diameter, and vary in length according to
the width of the machine. There are from twelve to fifty of these
cylinders, their number depending upon the character and weight of the
paper to be produced, very heavy sheets requiring many more drying
cylinders than sheets of lighter weight.
♦Tensile strength♦
Strange, almost phenomenal, conditions come about in the transformation
from filmy pulp to finished paper. A sheet which, though formed, is
at the first press-roll too fragile to carry its own weight, becomes
possessed of a final strength and power that is almost incredible. The
myriad of minute fibers composing the sheet, upon drying uniformly,
possesses great aggregate strength. A sheet of paper yields readily to
tearing, but the same sheet, when a perfectly even tension is applied,
will demonstrate that it is possessed of wonderful resisting power.
In evidence may be cited an instance that seems almost beyond belief.
Through some curious mishap a web of heavy paper, in fact, bristol
board, which had been thoroughly formed, was suddenly superheated and
then cooled while still on the driers. This was caused by a difference
in temperature of the driers and resulted in the sudden contraction of
the web of bristol; the strain on the machine was so great that not
only were the driving-cogs broken on two of the driers around which
the paper was at the moment passing, but the driers themselves were
actually lifted out of place, showing a resisting power in the paper
of at least several tons. ♦The calenders♦ The paper now passes to the
upright stack of rolls shown in the illustrations, which are known
as “calenders.” The word is derived from calendra; a corruption of
cylindrus, a roller or cylinder, they are simply rollers revolving in
contact, and heated from the interior by steam. These calenders are
used for giving to the paper a smooth and even surface, and are also
employed in the smoothing and finishing of cloth. ♦Speed of machines♦
The speed with which the paper passes through these cylinders is
remarkable, from one hundred to five hundred feet running through and
over the machine in a minute; and in some of the most recent mills the
web is as wide as one hundred and fifty-six inches (thirteen feet);
this is very nearly double the average machine width of a few years
ago, while the speed has increased in proportionate ratio; only a very
few years ago the maximum speed was from two hundred and fifty to three
hundred feet per minute; at this writing (1900) there are machines
in operation which run as high as five hundred feet per minute. But
great as has been the increase in the production of paper, the demand
has kept pace steadily. The wonderful product of the rag-bag holds an
invincible position in the world’s economy.
[Illustration: THE SIZE-TUB--PAGE 81]
♦Five miles in a roll♦
For machine-finished book and print papers, as well as for other
cheaper grades, the process ends with the calenders, after which the
paper is slit into required widths by disk-knives, which are revolving,
and so cut continuously. Paper intended for web newspaper presses is
taken off in continuous rolls of the widths required, varying from
seventeen to seventy-six inches, according to the size of the paper to
be printed. These reels contain from fifteen to twenty-five thousand
lineal feet of paper, or from three to five miles. The amount of paper
used in disseminating the news of the day is enormous; sometimes one
or two mills are required to manufacture the supply for a single
metropolitan daily, while one New York newspaper claims to have used
four hundred and fifty tons of paper in one Christmas edition, which is
about four times the amount of its regular daily consumption.
After having been slit into the proper widths by the revolving knives,
ordinary flat and book papers are cut into sheets by a straight knife
revolving at proper intervals on a horizontal drum. The paper, in
sheets, is carried by a traveling apron onto a receiving table at
the end of the machine, where the sheets as they fall are carefully
examined by experts, usually women, who remove any that may be
imperfect.
♦The immensity of modern machines♦
The entire length of a paper machine, from the screens to the
calenders, is about one hundred and twenty-five feet, while the
height varies, the average being about ten feet. The machines, while
necessarily of the finest adjustment, are ponderous and heavy, weighing
in some cases as much as four hundred tons, this being the weight of
the machine itself, exclusive of its foundations. The machine-room is
of necessity well lighted and thoroughly ventilated, and should be kept
clean throughout, as cleanliness is an essential factor in the making
of good paper.
♦Deckel edging♦
While the same general process applies to all classes of paper made,
the particular character of any paper that is to be produced determines
exactly the details of the process through which it shall pass, and
regulates the deviations to be made from the general operations in
order to secure special results. For example, some papers are wanted
with a rough or “antique” finish, as it is called; in such cases
calendering is omitted. Another special process is that by which the
paper is made with a ragged or “deckel edge”; this result is obtained
in some mills by playing a stream of water upon the edge of the pulp,
crushing and thinning it, and thus giving it a jagged appearance. At
the present time this “deckel-edge” paper is being quite extensively
used in high-class bookwork.
In the case of writing-papers, as has already been stated in the
description of the beating engines, a vegetable sizing made from
resinous matter is introduced into the paper pulp while it is still
in solution, and mixes with it thoroughly, thus filling more or less
completely the pores of the pulp fibers. This is found sufficient for
all ordinary book-papers, for papers that are to be printed upon in
the usual way, and for the cheapest grades of writing-paper, where
the requirements are not very exacting, and where a curtailment of
expense is necessary. For the higher grades of writing-paper, however,
a distinctly separate and additional process is required. ♦Tub sizing♦
These papers while on the machine in web form are passed through a vat
which is called the size-tub, and which is filled with a liquid sizing
made of gelatine from clippings of the horns, hides, and hoofs of
cattle, this gelatine or glue being mixed with dissolved alum and made
fluid in the vat. Papers which are treated in this way are known as
“animal,” or “tub-sized.”
♦Loft drying♦
We have duly described machine-dried papers, but these higher grades
of writing-papers are dried by what is known as loft, or pole-dried
process. Such paper is permitted to dry very slowly in a loft specially
constructed for the purpose, where it is hung on poles several days,
during which time the loft is kept at a temperature of about 100°
Fahrenheit.
Another detail of considerable importance is that of the “finish” or
surface of the paper. When paper with a particularly high or glossy
surface is desired it is subjected to a separate process after leaving
the paper machine, known as supercalendering.
♦Supercalendering♦
“Supercalendering” is effected by passing the web through the stack
of rolls shown in the illustration, which are similar to the machine
calenders already described. These rolls are composed of metal
cylinders, alternating with rolls made of solidified paper or cotton,
turned exactly true, the top and bottom rolls being of metal and
heavier than the others; a stack of supercalenders is necessarily
composed of an odd number of rolls, as seven, nine, or eleven. The
paper passes and repasses through these calenders until the requisite
degree of smoothness and polish has been acquired. ♦Electricity in
paper♦ The friction in this machine produces so much electricity
that ground wires are often used to carry it off, in order that the
paper may not become so highly charged as to attract dust or cause
the sheets to cling together. When the fine polish has been imparted,
the rolls of paper go to the cutting machines, which are automatic in
action, cutting regular sheets of the required length as the paper
is fed to them in a continuous web. In the manufacture of some high
grades of paper, such as linens and bonds, where an especially fine,
smooth surface is required, the sheets after being cut are arranged in
piles of from twelve to fifteen sheets, plates of zinc are inserted
alternately between them, and they are subjected to powerful hydraulic
pressure. ♦Plating♦ This process is termed “plating,” and is, of
course, very much more expensive than the process of supercalendering
described above.
♦Sorting♦
From the cutters, the sheets are carried to the inspectors, who are
seated in a row along an extended board table, before two divisions
with partitions ten or twelve inches high, affording spaces for the
sheets before and after sorting. The work of inspection is performed by
women, who detect almost instantly any blemish or imperfection in the
finished product as it passes through their hands. If the paper is to
be ruled for writing purposes, it is then taken to the ruling machines,
where it is passed under revolving disks or pens, set at regular
intervals. These convey the ruling ink to the paper as it passes on
through the machine, and thus form true and continuous lines. ♦Ruling
and folding♦ If the paper is to be folded after ruling, as in the
case of fine note-papers, the sheets pass on from the ruling machine
to the folding machines, which are entirely automatic in their action.
The paper is stacked at the back of the first folding guide, and is
fed in by the action of small rubber rollers, which loosen each sheet
from the one beneath, and push it forward until it is caught by the
folding apparatus. Man’s mechanical ingenuity has given to the machines
of his invention something that seems almost like human intelligence,
and in the case of the folding machine, the action is so regular
and perfect that there seems to be no need of an attendant, save to
furnish a constant supply of sheets. The folding completed, cutting
machines are again brought into requisition, to cut and trim the
sheets to the size of folded note or letter paper, which is the final
operation before they are sent out into the world on their mission
of usefulness. The finished paper may or may not have passed through
the ruling and folding process, but in either case it goes from the
cutters to the wrappers and packers, and then to the shipping-clerks,
all of whom perform the duties indicated by their names. The wonderful
transformation wrought by the magic wand of science and human
invention is complete, and what came into the factory as great bales of
offensive rags, disgusting to sight and smell, goes forth as delicate,
beautiful, perfected paper, redeemed from filth, and glorified into a
high and noble use. ♦Beauty of perfected paper♦ Purity and beauty have
come from what was foul and unwholesome; the highly useful has been
summoned forth from the seemingly useless; a product that is one of the
essential factors in the world’s progress, and that promises to serve
an ever-increasing purpose, has been developed from a material that
apparently held not the slightest promise. Well might the “Boston News
Letter” of 1769 exclaim in quaint old rhyme:
“Rags are as beauties which concealed lie,
But when in paper, charming to the eye!
Pray save your rags, new beauties to discover,
For of paper truly every one’s a lover;
By the pen and press such knowledge is displayed
As would not exist if paper was not made.”
And well may man pride himself on this achievement, this marvelous
transformation, which represents the fruitage of centuries of striving
and endeavor!
[Illustration: BLOWPIPES COOLING CALENDER ROLLS]
♦Wood pulp♦
Up to this point the reference has been almost entirely to paper
made from rags, but radical improvements have been made, caused by
the introduction of wood pulp, and these are of such importance that
the account would not be complete without some mention of them. These
changes are mainly in the methods of manipulating the wood to obtain
the pulp, for when that is ready, the process, from and including the
“washers” and “beaters,” is very similar to that already described. All
papers, whether made from rags or wood, depend upon vegetable fiber
for their substance and fundamental base, and it is found that the
different fibers used in paper-making, when finally subdued, do not
differ, in fact, whether obtained from rags or from the tree growing in
the forest. In the latter case the raw wood is subjected to chemical
treatment which destroys all resinous and foreign matters, leaving
merely the cellular tissue, which, it is found, does not differ in
substance from the cell tissue obtained after treating rags. In either
case, this cellular tissue, through the treatment to which the raw
material is subjected, becomes perfectly plastic or moldable, and while
the paper made from one differs slightly in certain characteristics
from the paper made from the other, they are nevertheless very similar,
and it might be safe to predict that further perfecting of processes
will eventually make them practically alike.
♦Mechanical wood♦
The woods used for this purpose are principally poplar and spruce, and
there are three classes of the wood pulp: (1) mechanical wood, (2)
soda process wood, and (3) sulphite wood pulp. The first method was
invented in Germany in 1844. The logs are hewn in the forest, roughly
barked, and shipped to the factory, where the first operation is to
cut them up by steam saws into blocks about two feet in length. Any
bark that may still cling to the log is removed by a rapidly revolving
corrugated wheel of steel, while the larger blocks are split by a steam
splitter. The next stage of their journey takes these blocks to a great
millstone, set perpendicularly instead of horizontally. Here a very
strong and ingenious machine receives one block at a time, and with an
automatically elastic pressure holds it sidewise against the millstone,
which, like the mills of the gods, “grinds exceeding fine,” and with
the aid of constantly flowing water rapidly reduces these blocks to a
pulpy form. This pulp is carried into tanks, from which it is passed
between rollers, which leave it in thick, damp sheets, which are folded
up evenly for shipment, or for storage for future use. If a paper-mill
is operated in connection with the pulp-mill, the wood pulp is not
necessarily rolled out in sheets, but is pumped directly from the tanks
to the beaters.
In the preparation of pulp by the other processes, the blocks are first
thrown into a chipping machine with great wheels, whose short, slanting
knives quickly cut the blocks into small chips.
♦The soda process♦
In the soda process, invented by M. Meliner in France in 1865, the
chips from spruce and poplar logs are boiled under pressure in a strong
solution of caustic soda.
♦The sulphite process♦
When sulphite wood pulp is to be prepared, the chips are conveyed from
the chipper into hoppers in the upper part of the building. Here they
are thrown into great upright iron boilers or digesters charged with
lime-water and fed with the fumes of sulphur, which is burned for the
purpose in a furnace adjoining the building, and which thus forms acid
sulphide of lime. The sulphite process was originally invented by a
celebrated Philadelphia chemist, but was perfected in Europe.
The “cooking,” or boiling, to which the wood is subjected in both the
soda and sulphite processes, effects a complete separation of all
resinous and foreign substances from the fine and true cell tissue, or
cellulose, which is left a pure fiber, ready for use as described. In
the case of all fibers, whether rag or wood, painstaking work counts,
and the excellence of the paper is largely dependent upon the time and
care given to the reduction of the pulp from the original raw material.
♦Components of print-paper♦
Chemical wood pulp of the best quality makes an excellent product,
and is largely used for both print and book paper; it is frequently
mixed with rag pulp, making a paper that can scarcely be distinguished
from that made entirely from fine rags, though it is not of the proper
firmness for the best flat or writing papers. All ordinary newspapers,
as well as some of the cheaper grades of book and wrapping paper, are
made entirely from wood, the sulphite or soda process supplying the
fiber and ground wood being used as a filler. In the average newspaper
of to-day’s issue, twenty-five per cent of sulphite fiber is sufficient
to carry seventy-five per cent of the ground wood filler. The value of
the idea is an economical one entirely, as the ground wood employed
costs less than any other of the component parts of a print-paper sheet.
The cylinder machine, to which reference was made earlier in the
chapter, was patented in 1809 by a prominent paper-maker of England,
Mr. John Dickinson. In this machine, a cylinder covered with wire cloth
revolves with its lower portion dipping into a vat of pulp, while by
suction a partial vacuum is maintained in the cylinder, causing the
pulp to cling to the wire until it is conveyed to a covered cylinder,
which takes it up and carries it forward in a manner similar to the
system already described. This machine is employed in making strawboard
and other heavy and cheap grades of paper.
♦Esparto♦
Generous Mother Nature, who supplies man’s wants in such bountiful
fashion, has furnished on her plains and in her forests an abundance
of material that may be transformed into this fine product of human
ingenuity. Esparto, a Spanish grass grown in South Africa, has entered
largely into the making of print-paper in England. Mixed with rags it
makes an excellent product, but the chemicals required to free it from
resin and gritty silica are expensive, while the cost of importation
has rendered its use in America impractical. Flax, hemp, manila,
jute and straw, and of course old paper that has been once used, are
extensively employed in this manufacture, the process beginning with
the chemical treatment and boiling that are found necessary in the
manipulation of rags. The successful use of these materials has met
demands that would not otherwise have been supplied. As a result, the
price has been so cheapened that the demand for paper has greatly
increased, and its use has been extended to many and various purposes,
which are mentioned in the following chapter, in an enumeration of the
various kinds of paper.
Many additional items of interest might be described in connection with
the methods of manufacturing paper, but as this work is intended for
the general reader, rather than for the manufacturer, those wishing
further information are referred to technical works on the subject.
♦Government bank-note paper♦
The best linen rags are used for the highest grades of writing and
bond papers, while ordinary note, letter, and flat papers are made
from cotton rags. In some mills, such as the government mill at
Dalton, Massachusetts, where government paper is made for bank-notes,
and in others where the finest ledger papers are manufactured, none
but new, clean linen rags are used. These come from the remnants
left in the making of linen goods. In the government mill where is
made the paper for our national currency, or “greenbacks,” there is
a special attachment on the machine for introducing into the paper
the silk threads that are always to be seen in our paper money. This
attachment is just above the “wire” on the machine, and consists of a
little conducting trough, through which flows, from a receptacle near
the machine, a stream of water holding the silk threads in solution.
The trough extends across the machine, and is provided at intervals
with openings, through which the short pieces of silk thread are
automatically released, and sprinkled continuously onto the web of pulp
as it passes beneath. ♦To prevent counterfeiting♦ The paper is thus
distinguished, and infringement and possible counterfeiting are made
extremely difficult by the fact that the government absolutely forbids
the making of paper by others under a similar process, as well as the
production of any paper containing these silk threads. The laws of
the United States pertaining to anything that borders on infringement
of our various money issues, both metal and currency, are most rigid;
anything approaching a similarity of impression is prohibited, and
a cut, stamp, or impression of any character that approaches in its
appearance any money issue of our government is considered a violation
of the law against counterfeiting, and is dealt with severely. The
government takes the same uncompromising position in regard to the
fabrics used in printing its paper-money issues, and it will be quickly
seen that the silk thread process above described is so great a
variation from anything required in the mercantile world that it would
be difficult to produce a paper at all similar without an ulterior
purpose being at once apparent. For this reason, the silk thread
interspersion is in reality a very effective medium in preventing
counterfeiting, not only on account of its peculiar appearance, but
also because of the elaborate methods necessary in its production.
In those mills making the finest grades of paper, much of the process
of thrashing, beating, dusting, and cleaning necessary in the ordinary
mill is omitted. The cleanliness and brightness which are reached only
at the “washer” and “beater” engines in the process of manufacturing
the lower grades of paper from cheaper rags, prevail at every step in
these higher grade mills.
♦Pure water necessary♦
One of the first requisites in making good paper, especially the
better grades, is an abundance of pure water, and spring-water, where
available, is preferred.
The effort has been made in the description given to cover the process
of making paper from the crudest rags. In enumerating the several
kinds of paper, in another chapter, brief reference will be made to
the varying methods required in their manufacture. In this chapter, no
attempt has been made to cover more than the principal divisions or
varieties of paper--writing, print, and wrapping papers.
♦The center of the industry♦
The United States, with characteristic enterprise, leads the world in
paper-making, supplying about one-third of all that is used on the
globe. The city of Holyoke, in Massachusetts, is the greatest paper
center in the world, turning out each working-day some two hundred
tons of paper, nearly one-half of which is “tub-sized,” “loft-dried”
writings. The region in the vicinity of Holyoke is dotted with
paper-mills, and within a few miles of the city is made about one-half
of all the “loft-dried” writings produced in the United States. The
tiny acorn planted two centuries ago has waxed with the years, gaining
strength and vigor with the increasing strength of the nation, till now
it has become a giant oak, whose branches extend to the lands beyond
the seas.
[Illustration: SLITTING AND WINDING--PAGE 78]