Improvements in Pulp Drying or Paper Making Machines.
Year: 1893

page_text: Date of Application; 14th Feb., 1893-Accepted, 18th Mar., 1893
COMPLETE SPECIFICATION.
[Communicated from abroad by HENRY FAIRBANKS, of St. Johnsburg, Caledonia
County, Vermont, United States of America, Manufacturer.]
Improvements in Pulp Drying or Paper Making Machines.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 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:-
This invention relates to paper-making machinery, and more especially to the
ordinary wet machine used for removing the water of suspension from paper pulp,"
in which the thin pulp, as it comes from the grinder or beating engine, is made to
deposit its fibres upon the surface of a mold-roll from which the soft layer is
taken upon a felt
aproo, dried on the way, and finally rolled upon a press-roll, or
taken off as paper.
In a machine constructed according to this invention the hollow couch-roll is
arranged in fixed bearings, the cylindrical surface of the said roll is perforated,
and the interior thereof is connected with a large volume exhaust. The mold-roll
is arranged to move towards the couch, driven by power, and preferably exhausted;
the felt apron passes over a large suction-box, of which a travelling porous belt
forms the top, said box being also connected with the exhaust; and the hollow
under press-roll, over which the felt passes, is perforated and preferably connected
with the exhaust.
This special or large volume exhaust for the mold-roll, couch-rolls, suction-box
and press-rolls, either or all, consists of an exhausting fan or fans, connected by
suitable tubes or passage ways with the interiors of said parts, and adapted to
induce, through their permeable surfaces, air-currents of moderate tension, but of
great volume and remarkable efficiency.
In the use of such exhausting-fans I depart considerably from the usual methods
of utilizing such devices, in that I do not attempt to tightly close all openings in
the rolls, boxes, or other chambers to be exhausted, other than the perforations in
their surfaces on which the pulp is carried; but, on the contrary, by leaving
certain portions of the rolls, boxes, and the like, wholly or partially uncovered, or
by other means, expressly provide air-inlets for the admission of air to their
interiors without passing it through the pulp-layer; and I provide an exhaust or
sufficient power and volume to maintain a strong suction current inwardly, not only
through the pulp carrying surfaces, but also through such inlets; thus not only
drawing in the water rapidly from the pulp-layer, but blowing or sweeping it off in
the form of spray or mist from the inside of the straining surfaces.
In the accompanying drawings:
Figure 1 is a side elevation, partly in vertical section, of a machine embodying
the
present invention.
Figures 2 and 3 are transverse sections on the lines x x and y y respectively, of
Figure 1.
Figure 4 is an elevation of the pulp-vat or tank, with a part broken away to show
the yielding bearing of the mold-rolls.
2-2, of
Figure 5 is a vertical section of the vat and felt apron taken on the line
Figure 4, with part of the shell and packing broken away to show such yielding
bearing.
Figure 6 is a transverse section through the suction-box, in the plane of its
exhaust outlet Y. Figure 1.

page_text: Figure 7, is a detail illustrating the perforated under press-roll, with its exhaust-
pipe and driving pulleys.
In the common wet machine the mold-roll is arranged in fixed bearings, and the
couch-roll carrying the felt rests its weight upon the mold roll, the felt carrying it
by its surface friction. In this construction the pressure is too great and unequal,
the felt sometimes lifting, and the movement is at the expense of great strain and
wear of the felt.
According to this invention the couch roll C is in. fixed bearings and the axis
of the mold-roll B runs in bearings just inside the ends of the pulp-vat A, which
bearings are in levers D, Figures 1 and 5, arranged to swing, on a stud at one end,
directly towards the couch-roll, while the free end of each lever is connected by a
link. E to an adjustable spring F, on the upper edge of the pulp-vat. This
arrangement allows the mold-roll to be held with constant, light pressure in
yielding contact with the felt G under the couch-roll. The swinging levers D,
carrying the axis of the mold-roll B, are enclosed within a circular extension a of
the mold-roll, formed or fixed on the inner wall of the vat and of a diameter
equal to that of the mold-roll.
One end of the mold-roll is closed, the other open. The open end revolves, in
close. proximity to the edge of this extended shell a and the packing-strip B',
secured to either of them, laps over the crevice between their adjacent cylindrical
edges, so that the interiors of the mold-roll and of the shell a form substantially
one chamber, although the shell a may be stationary. The packing B₁ prevents
the entrance of too much air into the mould-roll where the edges of the roll
meet the edges of the shell a. Said packing does not interfere with the slight
movements of the mold-roll to and from the couch. An exhaust pipe H leads out
from within the shell a to the exhausting fan Z; said pipe may enter the shell a
near the top, while the water drawn through the surface of the roll flows away
through a pipe I, near the bottom, said pipe being carried down and arranged to
dip in water, so that the flow from it will not be reversed by the exhaust.
When in operation, as shown in Figure 1, a portion of the permeable,
cylindrical surface of the mold-roll is submerged in the pulp, a second portion
is covered by the film of pulp taken up. and on its way to the apron; a third
portion is covered by the apron in contact with the pulp, which it takes off and
carries over the couch-roll; and a fourth portion, to wit, that between its line of
contact with the couch-roll and the point where it enters the pulp, is uncovered
and exposed to the free entrance of the air-current created by the exhaust. A
sufficient amount of air to fully supply the exhaust is however not admitted through
this portion of the roll, and a strong inward current is still maintained through
the portion of the roll carrying the pulp and that in contact with the felt.
A strong inward suction is also exerted upon the portion submerged in the pulp.
The effect of this exhaust throughout the roll is to materially aid in the deposit
of pulp upon the submerged surface of the roll, and to draw in water rapidly from
the pulp-layer so deposited. The water runs off freely through the outlet pro-
vided, or is drawn out through the exhaust passages in the form of spray or mist.
Under this system a much smaller cylinder than is usually required for the mold-
roll becomes equally effective in taking up a heavy, even web.
At the end of the mold-roll opposite the exhaust outlet Figure 3, we put upon
the outer end of the pulp-vat a hollow projection or bracket J, furnishing a bearing
for a short arbor K, in the line of the usual position of the axis of the mold-roll.
The inner end of said arbor carries the first fork of a common double universal-
joint L, of which the last fork is the end of the axis of the mold-roll; so that said
arbor and axis, while not rigidly connected, must rotate together. The outer end
of said arbor carries a gear-wheel M, of the same diameter as the mold-roll and
gearing it to the couch-roll, so that said rolls rotate with equal and coincident
peripheral travel. The couch-roll is connected with the press-roll P, over which.
the felt passes, by a belt or by two sets of bevel gears, not shown, in such a manner

page_text: that said press-roll rotates at the same speed as the mold-roll and couch, and the
felt is relieved from strain.
By reason of the drying action of the exhaust through the mold-roll upon the
pulp layer the pulp taken up is thicker before it reaches the apron than in the
ordinary machines, and therefore lies more upon the surface of the felt, so that less
washing of the felt is necessary to keep it clean, and it lasts much longer.
The couch-roll C of this machine carries the felt G, as usual. The roll being in
fixed bearings the tension upon the felt is constant. Its cylindrical surface is
perforated and its hollow interior connected with the exhaust. I usually cover the
surface of the roll with one or two thicknesses of porous cloth, through which
light covering the strong exhaust current readily passes, spraying the water drawn
through the felt from the pulp and carrying it rapidly away from the inner surface
of the roll, both that part of said surface which is under the felt and that part
which is not. Said cloth covering being partially dried during that part of the
roll's revolution when the felt does not rest upon it, is in condition when it again
meets the felt to absorb the water rapidly from the felt and the pulp layer thereon.
Sufficient air passes through the said covering and the part of the roll which is
free from the felt to partially but not fully supply the exhaust, so that a
considerable portion of the inward current must pass through the felt and pulp.
I also perforate the peripheral surface of the hollow under press-roll P,
Figures 1 and 7, which carries the felt apron at the other end of the machine. It
is also connected with the exhaust, and the water pressed or drawn down from the
pulp through the felt passes freely into the interior of the roll, thus making the
pulp more dry as it winds upon the upper press-roll Q. Air to supply the exhaust
current in addition to what passes through the felt, enters that portion of the roll
not covered by the felt.
Another feature of this invention is a large suction-box S, Figures 1, 2 and 6,
of special and novel construction connected with the exhaust by a suitable pipe Y,
and applied to the under surface of the pulp-bearing felt, so as to still more
rapidly dry the web of pulp.
While the details of construction may be varied in its essential parts the suction
box consists of a box extending under the felt from one side thereof to the other,
and as long in the direction of the length of the felt as may be required, preferably
about three feet; closed except the top, which is covered by a section of a travelling,
porous belt T, arranged to move with the felt which rests upon it. The belt T may
pass over rollers R, forming the ends of the box, and in that case may return
under the bottom of the box, the end rollers running close to the bottom and sides
and forming the only air-stop needed. But I prefer the construction shown in
which the belt T returns inside the box S, its edges, being secured to flexible, flat-
linked, riveted chains U, which runs close to the sides of the box, being held apart
by a series of transverse bars V, under the belt, which enter corresponding grooves
in the end rollers, so that an accurate movement of the belt is secured. The ends
of the box approach close to the belt, but sufficient air can enter at these points or
between the chain edges and the sides of the box to provide a sufficient supply of
air for the exhaust in addition to what passes through the felt.
To direct and control this current any suitable packing may be employed. The
rubber cloth strips W, at the edges of the belt, which may be wider as the web of
the paper is narrower, may just touch the sides of the box and act as a packing.
The packing should not be so close as to prevent the entrance of a proper amount
of air, and still close enough to ensure the passage of a certain amount of current
through the felt and the pulp thereon, the highest efficiency of the apparatus being
secured, as in the case of the mold-roll, couch-roll and press-roll, by the proper
adjustment of the quantity of air drawn through the pulp relatively to that
admitted through other inlets. If the described air-inlets to the suction-box are
insufficient, others may be provided, so placed that the currents entering them will
strike the under surface of the porous belt. The axis of one of the rollers R,
extends through the side of the box and carries'a gear wheel or a pulley by which

page_text: it is so connected by a shaft or a belt R', Figure 1, to the rolls carrying the felt
apron G, that said apron and the belt T, in the suction box, move together without
any sliding friction between them. The belt T moves so easily that the apron
resting upon it would carry it, but driving it by power relieves the apron of all
possible strain from this source. The transverse bars V, which support the belt T
against the pressure of the atmosphere while under the apron, slide upon smooth
tracks X secured to the inner sides of the box, parallel with its top, or said bars
and the chains U may be supported by other means. The suction-box described will
work as well under a wire apron as under the felt apron of this machine, and will
be equally valuable.
The large volume fan-exhaust described is of very great importance in securing
the rapid removal of water from the pulp, and we apply it to the mold-roll, the
suction-couch, the large suction-box and the under press roll or either of them, and
preferably by branch pipes leading to each of the said enclosures from the fan as
shown in Figure 1. The exhausting devices that have heretofore been commonly
used, based merely on the idea of introducing a vacuum under the pulp, are
effective in a very small way if no air leaks in, but the necessary leakage into the
enclosures so operated upon greatly reduces the degree of exhaustion effected and
destroys the efficiency of the apparatus.
My improvements involve the substitution of the large volume, ventilated fan-
exhaust current, maintained through the entire permeable surface of the rolls and
under, as well as through, the felt passing over the rolls and suction box, for the
high pressure exhaust attempted by the use of air pumps or other means.
Parts of this improved machine may be used without using the whole. The
counter-balanced mold-roll, rising to its work, may be used where a suction-couch
takes the place of a felt in transferring the web of pulp to the press-roll, or when
in a paper machine a felt passes over several mold rolls; any mold-roll and couch-
roll may be geared and driven by power, the one in adjustable bearings being
connected to its gear wheel through a universal joint; either roll may be connected
with an exhaust constructed on our system, while the others are not; and the
suction-box described may be used without the suction-rolls, or the rolls without
the box.
I believe that these several improvements, as thus specified, constitute a marked
advance in the means of treating webs of pulp, and will materially reduce the
percentage of moisture therein, as compared with the product of apparatus hereto-
fore known..
Having now particularly described and ascertained the nature of this 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 :-
1. In a pulp-drying or paper-making machine, the couch roll and fixed bearings
in which it is mounted, in combination with the mold-roll and yielding bearings in
which it is mounted, for the purpose herein set forth.
2. In a pulp-drying or paper-making machine, a hollow permeable mold-roll and
couch-roll, and mechanism adapted to raise the mold-roll into yielding contact with
the conch-roll, in combination with a short arbor, substantially a prolongation of
the axis of the mold-roll, but, in fixed bearings, and carrying the drive-wheel,
and with an universal joint connecting said arbor and axis, for the purpose set
forth.
3. In a pulp drying or paper-making machine, a hollow perforated suction couch-
roll and fixed bearings in which it is mounted, and a hollow permeable mold-roll
with yielding bearings in which it is mounted, in combination with a travelling
apron passing between and pressed by said rolls, and with an exhausting apparatus
connected with the interior of said couch-roll by an exhaust passage, substantially
as set forth.
4. In a pulp drying or paper-making machine, the combination of moving,
permeable surfaces of suitable material adapted to receive, support or carry the

page_text: film of pulp, enclosed chambers within or beneath such moving, permeable surfaces,
air-tubes or passages leading from such chambers to a rotary exhausting fan
mounted at the end of such air passages and adapted to produce and maintain an
exhaust air current of large volume inwardly through such permeable surfaces and
the film of pulp thereon; suitable vents being also provided to permit the ingress
of air to said enclosures without passing it through said pulp, substantially as
described.
5. In a pulp drying or paper-making machine, a pulp vat, a pulp carrying apron,
a hollow, rotating mold-roll mounted in the pulp-vat and adapted to be partially
submerged in the pulp therein, said roll having its ends closed, its whole interior
formed substantially in one chamber, and having a pervious cylindrical surface
adapted to permit free ingress of air and water, in combination with a rotary
exhausting fan connected by a suitable tube or passage with the interior of said
roll and adapted to maintain a suction-air-current of large volume inwardly through
the unsubmerged portion of the surface of said roll and a flow of water inwardly
through the submerged portion thereof, substantially as described.
6. In a pulp-drying or paper-making machine, in combination with the endless
travelling apron carrying the layer of pulp, a hollow roll over which the apron
passes, said roll having its ends closed, its cylindrical surface perforated or other-
wise made permeable to air and water, and so adjusted that when in operation a
portion of its said surface will be covered by the pulp-carrying apron, and the
remaining portion wholly or partially uncovered and exposed to the free inflow of
the air-current through its said permeable surface, and a rotary exhausting fan
connected by suitable passages with the interior of said roll and adapted to maintain
a continuous exhaust air-current inwardly through the permeable surface of said roll
and through and beneath said apron, and the pulp layer thereon, substantially as
set forth.
7. In a pulp-drying or paper-making machine, the combination of the moving
endless apron carrying the web of pulp a suction box over the top of which the
apron passes and provided with suitable air-inlets admitting the air into its interior
transverse rollers journalled in the ends of said box, a permeable endless travelling
belt mounted on said rollers and moving over the top of said box beneath and in
continuous supporting contact with the pulp-carrying apron, and a rotary exhausting
fan connected by suitable passages with the interior of said box and adapted to
maintain an exhaust air-current of large volume inwardly through and beneath said
belt and apron and the web of pulp thereon, substantially as set forth.
8. In a pulp-drying or paper-making machine having a suction-box with a
travelling top, the combination of transverse supporting bars across the belt which
forms the top of said box, link-work at the edges of this belt, and carrying rolls at
the ends of the box, to which rolls the said links and bars are fitted, adapting the
said top of the box to be carried forward, coincidently with the pulp-carrying
apron by the movement of the turning rolls, and to support this apron against the
pressure of the atmosphere, substantially as herein set forth.
9. In a pulp-drying or paper-making machine, in combination with the pulp
carrying apron, a suction box of which the upper side is a permeable endless belt
located beneath the pulp-carrying surface of the apron, and in contact with it, with
means for supporting the flat surface of the belt forming this upper side, and end
rollers over which it passes, having their bearings in the sides of the box, and
driven by power supplied to one or both of these rollers whereby the belt is driven
at the same speed as the apron resting upon it, substantially as set forth.
Dated thin 14th
fnb 1002
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.