Improvements in Suction Devices for Paper Making and Pulp Drying Machines.
Year: 1895

page_text: Date of Application, 3rd Sept., 1895-Accepted, 4th Apr., 1896
COMPLETE SPECIFICATION.
Improvements in Suction Devices for Paper Making and
Pulp Drying Machines.
I, HENRY FAIRBANKS, of St. Johnsbury, Vermont, United States of America,
Manufacturer, 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 suction devices for paper making machines.
In paper machines and pulp drying machines, where the layer of wet pulp is
carried upon an endless apron of wire cloth or felt, it is customary to have this
moving apron, which is loaded with the pulp layer, slide over the perforated or
open tops of narrow boxes partially exhausted of air, for the purpose of drawing
some of the water from the pulp, and leaving less to be pressed out in the further
treatment. The atmospheric pressure upon the apron makes it drag heavily over
these suction boxes, and it is thereby subjected to very severe strain and wear.
To avoid this, rotary suction boxes have been tried, but the apron moving over
these is in contact with only a very small part of the cylindrical surface, and they
have not proved efficient, and closed suction boxes with flat travelling tops as have
hitherto been described have not come into use.
My invention consists in providing a series of suction boxes, each as long as the
apron is wide, driven by power, moving with the apron, together forming a large
flat exhausted surface on which this apron rests, and upon which the weight of the
atmosphere may press it without causing any wear or strain, since all sliding
friction is avoided. Moving with the apron as far as required, they then drop
away from it, and return underneath, to their starting point. These boxes are
preferably semi-cylindrical, with closed ends, and having a flat top, in the plane of
the diameter of the semi-cylinder, formed of perforated sheet metal. These boxes
are attached at the ends to the links of two endless chains carried by properly
formed sprocket wheels, which links also carry rollers by which the boxes while
in contact with the apron above, are supported, and ride upon tracks, returning
underneath the same. Each box is connected by a flexible hose pipe with one of
a series of holes through a rotary disk, which has as many holes as there are
suction boxes, and in the rotation of the disk, these holes register with a small
exhaust chamber, through which the boxes that for the time are in contact with
the apron above them, are brought into internal communication with a strong air
pump. A series of gear wheels give equal motion to the sprocket wheels at the
two sides of the machines, and also to the rotary disk in the middle, which is
speeded so as to make its rotation agree with the revolution of the whole series
of suction boxes, so as to keep the flexible hose pipes from crossing.
In the accompanying drawing
Figure 1 is a partial. side elevation, showing the relation of the boxes, to the
links supporting them, and the rollers and the sprocket wheels carrying them.
Figure 2 shows in perspective the principal parts of the suction devices, the
sides being removed.
Figure 3 is a longitudinal section showing the boxes, the rotary disk, and the
flexible hose connections between them.
Figure 4 is a perspective view showing a single box with its connections.
Figure 5 is a side elevation, showing the arrangement of two similar series of
such boxes, placed so that the pulp resting over the edges of the boxes of one

page_text: series shall in the movement of the apron come over the middle of those of the
other series, a levelling or dandy roll being applied to the surface of pulp as it
passes from one series to the other.
In all the figures, similar letters of reference are used to designate similar
parts.
The semi-cylindrical boxes i are closed at the ends, and are perforated at their
tops m. Each end of the said boxes is attached to a link, and at each joint of
these links is a roller r, on the inner side of the endless chain, and on the outer
side a projection or short stud fitting the forks f, f, of the sprocket wheels e. The
sprocket wheel c, and gear wheel a, are upon a short arbor on one side of the
machine, as are the corresponding wheels upon the other side of the machine, there
being no shaft across the machine to connect them together as the space must be
left clear for the movement of the flexible hose.
The gear wheels at each side of the machine are connected together by the
shaft o, of the gear wheels o, o, or by the shaft of the wheel d, the speed of the
wheel e, being reduced through the wheels b, and c, to d, which moves slower in
proportion as the number of the suction boxes in the whole series is greater than
the number of forks f, f in the sprocket wheel e, that is, slower in proportion as
the revolution of the whole series of boxes is slower than the rotation of the
wheels a. Motion is communicated to the whole series of gear wheels by a
connecting wheel not shown, which being properly geared causes the surface of the
boxes to move at the same speed as the apron which rests upon them, and relieves
this apron from the strain incident to carrying them.
The rollers r, r, carrying the endless chains to which the boxes are attached, roll
upon and are supported by the tracks q, q, which are level across the top, but bend
down at the ends, so that when a box begins to turn down, as at h, in the
movement indicated by the arrow p, the rising edge is not thrown above the
level of the apron 2.
The flexible hose pipes k, k, are made of material that will not collapse under
atmospheric pressure, and connect the boxes with corresponding holes n, n, in the
disk j, as shown in Figure 4. This disk j, is attached to the shaft a, of the gear
wheel d, and its flat side is in practically air-tight connection with the stationary
plate w, carrying the small, are shaped exhaust air chamber y, which fits the disk j,
and brings a certain number of the openings n, n, near the edge of the disk j, into
communication with the exhaust pipe s, leading to the air-pump, or other strong
exhauster.
In this manner a predetermined number of the boxes in the middle of the top of
the series, and in contact with the apron, are subjected to a strong exhaust current.
The boxes when moving in contact with the apron are close together, their edges
formed with strips of elastic material meet each other so that the exhaust action
upon the pulp on the belt resting upon them is practically continuous through the
scries. But if it proves to be less at the lines where the boxes meet, the machine
may be speeded so that the boxes will travel a little faster than the apron, helping
in its movement, and providing that no part of the pulp shall miss the full action
of the exhaust. This equalizing of exhaust action will be effected still more
completely by providing two series of suction boxes arranged as shown in Figure 5,
where the pulp that has been over the middle of each box of the right hand series,
as at u, will come over the meeting edges of the boxes of the left hand group
at u¹.
In case the pulp carrying apron moves uniformly with the boxes, and there is
but a single series of these, coarse perforations in their flat tops will give corre-
sponding water marks in the paper, and these may be arranged to form any desired
figures, but fine uniform perforations, or wire cloth over the perforated sheets will
give uniform paper. The dandy-roll z, between the two series or at the end of one
will help to lay the surface of the paper.
To adapt the device to use upon paper narrower than the full width of the
apron, each box is provided with sliding heads controlled by a long screw having a

page_text: right and thread at one end and a left hand one at the other, in the manner
common in suction boxes, which being common requires no illustration.
Having described what we consider the best way of carrying out our invention,
it will be apparent that the details of this machine may be much varied without
altogether destroying its efficiency. The shape of the travelling suction boxes,
the method of mounting and propelling them may be different, the gearing need
not be the same, and the connection with the exhaust may be otherwise arranged. By
forming the boxes with suitable valve seats they might be made to register directly
with properly shaped opening in an exhaust chamber, without the intervention of
the flexible hose pipes and rotary disk. Such a series might be carried by the
travelling apron and the gearing dispensed with. But a mechanic will easily see
the advantages of the full plan which we have adopted.
Having now particularly described and ascertained the nature of my said inven-.
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a paper machine or a pulp drying machine, the combination of an endless
apron adapted to carry wet pulp, with a series of travelling suction boxes
successively carried beneath, and in working contact under said apron, and with
means for exhausting the same, substantially as and for the purpose herein.
specified.
2. In a paper machine or a pulp drying machine, the combination of an endless
apron carrying wet pulp, with partially exhausted travelling suction boxes carried
successively beneath and in supporting contact under said apron, and with the
endless chains conuecting them in series, and the tracks upon which they ride,.
directing their motion as herein described.
3. In a paper machine or a pulp drying machine, the combination of an endless
apron adapted to carry wet pulp, with partially exhausted travelling suction boxes
carried successively beneath and in working contact under said apron, and with the
endless chains connecting them in series, and the sprocket wheels and gear con-.
nections whereby they are carried forward with the same movement as the apron
resting upon them substantially as and for the purpose specified.
4. In a paper machine or a pulp drying machine, the combination of an endless
apron adapted to carry wet pulp, with a series of open top boxes, means for moving
them beneath and in contact with said apron, the exhaust chamber y communicating
with said boxes and the exhaust pipe, as herein fully described.
5. In a paper machine or a pulp drying machine, the combination of the endless
apron, adapted to carry wet pulp, upon one side, with the suction boxes i, i, in
working contact with the other side of the said apron, the flexible hose pipes k, k,
the disk j, on a shaft geared to move with the series of boxes, the exhaust
chamber with which the flexible hose from the boxes communicates, and the
exhaust pipe s, constructed and arranged substantially as set forth.
y
6. In a paper machine or a pulp drying machine, the combination of the endless
apron v, adapted to carry wet pulp with the open top boxes i, i, upon which this
apron rests, the flexible hose pipes k, k, connecting these boxes to the openings n,,.
of the disk j, and the exhaust chamber y, and with the supporting track the
links 1, 1, the sprocket wheels e, and the gear wheels a, b, c, and d, constructed and
arranged for joint action substantially as and for the purpose herein described.
Dated this 3rd day of September 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.