Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2~31~2
The invention relates to cutting apparatus for
cuttiny thin web materials, and in particular, to a cutter
for cutting a web of paper moving at high speed, and a
method of cutting this web mat:erial.
BACKGROUND OF THE INVENTION
The cutting of paper during manufacture in a paper
making machine presents a series of problems. The web of
paper will be moving through the machine at high speeds,
and cuts may be required which are longitudinal and also
more importantly which are diagonal to the axis of the web.
During the manufacture of paper, the wet fibre sheet
(pulp or paper) is fed around drying rollers or dryers, by
means of blankets which squeeze the paper/pulp on to the
dryers. The dryers are heated, and the pulp is rapidly
dried. There may be a multitude of such drying rolls and
webs in the machine, and it is necessary to run the machine
~ontinuously without stopping, as long as there is ~ibre
being fed from the upstream end. The web of paper becomes
- progressively longPr, as it passes from the upstream end to
the downstream end of the line, and thus the dryers must be
run progressively faster and faster, from the upstream end
to the downstream end.
At the downstream end, the dried paper web which is
then moving at high speed is then fed onto a stack of
vertical rolls known as a calender (not shown) and from
there to a wind-up station or reel to form rolls of paper
around reel bars (not shown). The rolls are. then removed
for finishing and delivery to customers.
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It is well known that the web o~ paper at the
downstream end, just prior to the calender and reel is
fragile, and in practice breakages in the web before, or at
-this point are relatively frequent.
The web, which may for example be thirty feet wida,
must then be, as it were, re--threaded onto the calender
stack and re-threaded again onto the reel.
With a full width web, this is simply impractical.
In fact, the practice is to cut what is called a "tail"
which may be about three inches wide, on one side of the
web, and the tail is then re-threaded, typically for
example by an air blast, into the afor~mentioned calender
and reel sections (the downstream wind-up rolls). The tail
will then carry the rest of the web on its desired path.
The web will usually break between the last of the
dryers, and the aforementioned wind-up sections of the
line. Accordingly, the tail ut may be made one or two
dry~rs back up the line from its downstream end, at a
position where the web of paper is still securely stretched
between two sets of dryers. The cutting of this tail,
first of ~11 involves the making of a first longitudinal
cut parallel to the edge of the web to create the tail, and
then a second transverse cut back over to the first edge o~
the webO
These cuts are, of course, made while the web is
still moving at high speed and con equently, the transverse
cut, in fact, produces a cut which is diagonal to the axis
of the web.
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In the past, this has been done b~ various mechanical
devices such as fixed knife blades, and rotating knif0
blades and the like. carriages have been provided to move
the knife blades from one sid~e of the web to the other and
back again in various ways. These solutions however have
not been entirely satisfactory. A principal problem is the
fact that paper is a relatively abrasive material, and when
a knife blade is held in a web of paper moving at high
speed it rapidly becomes dull. The tail cutting operation
may have to be performed several times in a single shift,
and the kni~e used must be re-sharpened between each
cutting operation, in order to maintain continuity of
production.
Howev~r, any knife blade whether fixed or rotary is
inherently unsuitable for making a diagonal cut in a moving
web of paper. Since the knife blade must be held with its
edge lying along the longitudinal axis of the web, then
when the knife blade is moved sideways transversely, the
side surface of the blade will be pressed against the web
and it will tend to tear rather than cut. This problem is,
of course, greatly aggravated when using a rotary knife
blade, since it presents, relatively speaking, a far
greater width, when moved transversely across the moving
web o~ paper than a ~ixed knife blade.
It is highly desirable to provide some form of
cutting method having a device which produces a point cut
pre~erably without mechanical contact, so that when the
device is moved transversely, it does not present a side
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face to int~rfere with the web.
In th~ past, high pre~sure jet cutting d~vices have
been used in other applications. However these jet devices
have never been successfully applied to tail-cutting4 One
of the problems is that it i5 necessary to traverse the
cutting device over a distance of thirty feet or more,
i.e., the width of the web. llhe space where the cutting
device must be traversed is located between two sets of
dryers in the line and spac~ i5 relatively limited. In the
past, most known jet cutting systems developed the high
pressure jet cutting fluid at a location to one side of the
machine, and then ~ed the high pressure fluid to a nozzle,
by means of rigid high pressure hoses. Hoses capable of
handling these high pressures and temperatures were,
generally speaking, too rigid and massive and were
unsuitable for this type of application. In addition
~elatively large line losses were encountered leading to
substantial inefficiencies.
There are other applications in the paper-making
industry as well as in other industries, where jet cutting
devices are used as slitters, making straight longitudinal
cuts along the web axis. The systsms, of course, do not
encounter the type of problems described above. Nozzles
may be placed in a fixed location. High pressure fluid may
be supplied to the nozzles by suitable rigid metallic
;~;! plping, and a high pressure source such as a pump or
intensifier may be located to one side of the machine, in a
fixed location. Such systems were however incapable of
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2~3 ~802
making d.iagonal cuts in a moving web, and were in no way
comparable to the present invention.
The particular operation described above, namely the
cutting of a tail on a moving web of paper, presents these
- various problems in a particularly acute form. However,
-: generally.similar problems occur in the paper-making
industry, or in any other web processing industry, in any
:
; situation where it is attempted to cut a web moving at high
speed, wherein the cutting device moves diagonal to the web
axis. The invention is not to be confined solely to the
~ cutting of a tail for re-threading purposes, but is of
.; application to any situation where it is desired to form a
: diagonal cut or cuts in a web of material moving at high
speed.
~; BRIEF SUMMARY OF THE INVENTION
With a view to solving the various problems noted
above, the invention provides an apparatus for cutting a
moving web of thin material, said web passing around
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upstream and downstream rolls adjacent to one another, said
apparatus comprising conveyor means adapted to be
.~: positionDd between said upstream and downstream rolls,
carriage means movably mounted on saicl conveyor means
and adapted to be moved therealong, and power-operated
.~ movement means for moving the same, pressure intensifier
means mount:e~cl on said carriage means, whereby said
intensifier means may be moved by said carriage means
relative to said web, flexible jet fluid supply conduit
means connected to said intensifi~r means for supplying a
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jet fluid thereto at a predetermilled first pressure,
flexible power conduit means connected to said intensifier
means for supplying a power fluid thereto at a
predetermined second pressure, operation of said
intensifi2r means by said power fluid intensifying the
pressure of said jet fluid from said first pressur~ to a
predetermined third pressure, and jet nozzle means
connected to said intensifier means, and located at a point
closely overlying said web, and adapted to discharge said
jet fluid at said predetermined third pressure, whereby to
cut said web.
More particularly, it is an objective o~ the
invention to provide an apparatus having the foregoing
advantages, and including elongated housing means defining
a top wall, a rear wall, and a bottom wall, and wherein
said conveyor rail means are mounted on said top and bottom
~r walls, and wherein said jet fluid supply hose means and
said power ~luid power hose means are located within said
housing means.
More particularly, it is an objective of the
invention to provide an apparatus having the ~oregoing
advantages, and including an elongated flexible
hose support means located within said housing means, and
wherein said jet fluid supply hose means and said
power hose means are located within said flexible
hose support means, ~or movement in response to movement o~
said carriage means.
More particularly, it i5 an objective o~ the
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invention to provide an apparatus hav:ing the ~oregoing
advantages wherein said flexible hose support means is
secured approximately mid-way between the ends of said
housing means, on said bottom wall thereof, and wherein
said flexible hose support means extends along said botto~
wall, and upwardly towards sa:id top wall, and defines lower
and upper support portions, spaced apart from one another,
and a U-shaped bend portion extending therebetween.
More particularly, it is an objective of the
invention to provide an apparatus having the foregoing
advantages, and including carriage movement means,
connected to said carriage means, control guide means
at either end of said conveyor means, around which said
carriage drive means is guided, power operated means for
- moving said carriage drive means, whereby to move said
carriage means ~rom along said conveyor means in both
-; directions, and carriage drive support means on said
carriage means, engageable with said carriage drive means,
whereby to support the same intermediate said carriage
guide means.
~ Xt is a further and related sbjective of the
;~ invention to provide an apparatus having the foregoing
advantages and further including plate means located
~; adjacent to said jet nozzle means, and oriented at a
predetermined angle, whereby ts lie closely adjacent to
said web, and including openings in said plate means and
suction means adapted to withdraw air from the space
between said web and said plate means.
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2031~3~2
The v~rious features of novelty which characterize
the invention are poi.nted out with more particularity in
the claims annexed to and ~orming a part of this
disclosure. For a better understanding of the invention,
its operating advantages and specific objects attained by
its use, reference should be had to the accompanying
drawings and descriptive matter in which there are
illustrated and described preferred embodiments of the
invention.
IN THE DRAWINGS
Figure 1 is a perspective illustration partially cut
away, of upstream and downstream dryer rolls, carrying a
~ web, with the jet cutting apparatus of the invention, shown
-~ positioned between the two rolls;
Figure 2 is a section along the line 2-2 of Figure 1;
Figure 3 is a front elevational view of the apparatus
i .of Figure 1I with portions omitted for the sake of clarity,
:.
-'~ and showing a portion of the apparatus in a first or
retracted position;
-. 20 Figure 4 is a front elevational view corresponding to
Figure 1 showing a portion of the apparatus with the
carriage in a second or extended position;
Figure 5 is a perspective illustration of the
intensifier portion of the apparatus;
Figure 6 is a perspective illustration of an
alternate embodiment o the invention showin~ a modified
form of the plate portion and jet nozzle of the
intensifier, and,
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Figur~ 7 is a schema-tic plan view o~ a web of paper
showing the cuts made by the invention.
- DESCRIPTION OF A SPECIF'IC EMB5)DIMEMT
As described above, the invention relates generally
to the cutting o~ thin web mat:erial, and in particular, to
the cutting o~ such thin web materials which are in motion
at high speed such as thin paper webs in paper making
machines.
The particular embodiment illustrated is designed and
intended for the cutting of what is called a "tail" on a
web o~ paper moving at high speed through successive dryer
rolls in a paper making machine.
While it is not necessary ~or the purposes of this
description to describe all of the features of a paper
making machine, essentially, a paper making machine
consists o~ a large number of rolls, some of which are
heated for the purposes of drying the fibre. The fibre is
.
pressed against the rolls by a series of endless belts or
blankets. The rolls may be of considerable width, up to
thirty feet or more in many cases.
As the paper pulp moves from the upstream end to the
downstream end o~ the line of rolls, it progressively dries
out and becomes thinner and longer. Thus, the downstream
dryer rolls will be rotating at a much greater speed than
the upstream rolls, and in fact, the velocity o~ the web
around the last two or three dryer rolls may reach several
thousand feet per minute. As the paper web exits from the
last drying roll, it then passes to a calender and reel
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section.
During operation, it is well known that the web of
paper may become broksn or torn, often between the last
drying roll and the aforementioned calender and reel
sections, and in fact, this may happen several times per
day.
Due to its width, it is impractical to re-thread the
torn end of the web directly into the calender and
reel section. The practice for many years has been to cut
the web between two of the drying rolls upstream of the end
of the line, to provide what is called a "tail." A tail is
a strip of the web approximately three inches wide along
~,',7 one edge of the web. This was done by making a cut with an
implement such as a knife. The knife blade must be held
stationary about three inches from one edge of the web
while the tail is cut. Then the knife blade must be moved
back across the web, to the other edge of the web. Since
; the web is of course moving during this cutting operation,
the end result will be a single longitudinal cut parallel
to one edge, and a second diagonal cut across the web to
the other edge.
The tail is then more readily fed onto the calender
and reel section, usually by means of an air blast, and the
web will then re-thread itself through the calender and
reel stations.
During this operation, the major portion of the web
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` o* paper between the last roll and the calender and
reel section is simply discarded and in fact, is returned
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203~02
to the upstream end of the line and reprocessed as pulp.
Referring now to Fiyure 1, the invention is there
illustrated, being located between two dryer rolls of a
conventional paper making machine. The two rolls are
indicated as R1 and R2; R2 being downstream from R1. The
web of paper is passing from roll R1 upwardly, around roll
R2, in the direction of the arrow "a".
The entire device may also be located such, that it
would be positioned between roll R1 and previous upstream
roll (not shown), with the paper running in a downward
direction. The autting apparatus in accordance with the
invention is indicated by the general reference 10, and
~ comprises an elongated hollow support bar 12, and a
- carriage 14.
Hydraulic power is provided by means of th~
power fluid pump 16 driven, for example, by a prime mover :~
such as electri¢al motor 18.
~ A pressure intensifier 20, is mounted on the carriage
; 14, and develops a high pressure water jet at the nozzle
indicated generally as 22.
Referring now to Figures 2, 3 and 4~ the support bar
12 will be seen to comprise upper and lower elongated
plate members 30 and 32, a back wall 34 (Figure 1), and an
intermediate wall 36. The upper and lower walls, and the
` re~r wall and intermediate wall, together, form a hollow
box section o~ great rigidity, adapted to provide a solid
.: support for the device across the entire width of the web.
Suitable mounting means (not shown) will be connected to
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the bar 12 for mountiny at either end on appropriate
support structure (not shown).
Conveyor means are provided in the form of upper and
lower conveyor rails 38 and 40, formed alony the free edges
of upper and lower walls 30 and 32. A generally "U" shaped
channel member having walls 42, 44 and 46, is attached to
intermediate wall 36, and extends approximately one half
the length of the support bar 12, for reasons to be
described below.
The carriage means 14 comprises a carriage plate 48,
on which suitable wheels, such as whe~ls 50, are fastened
to register with conveyor rails 38 and 40. Rails 38 and 40
are "V" shaped in profile, and the wheels 50 are grooved to
ride along the rails. The intensifier 20 is fastened to
the plate 48 by any suitable means, represented by the
clamps 52.
. The plate 48 is provided at each end with a chain
attachment 54. Carriage drive means, namely 56 (Figures 3
and 4) are attached to the attachments 54. Chain 56 runs
: 20 around guide means, namely an idler sprocket 58 at one end
of the support bar 12, and at the other end, around a drive
sprocket 60, driven by a motor 62.
In order to assist in controlling and supporting the
upper run of the chain 56, support sprocket 64 is mounted
on wall 42 (Figure 2), having a chain retention device 66.
It will be appreciated that the intensi~ier 20
requires to be connected to a source of power fluid, and
may require a return, and also, a source of jet fluid.
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Since the carriage has to move from one end of the
support bar to the other, ~lexible supply hoses are
provided. In order to contain and control such flexible
hoses, a flexible hose jacket: 66 is provided, being secured
as at 68, to bottom wall 32. Flexible jacket 66 extends
along the bottom wall 32, ancl forms a 'IU'' bend, indicated
as 70, and an upper return portion 66a of the jacket 66
extends over wall 42. It is secured to a bracket 72, which
is in turn secured to plate 48.
As shown in Figures 3 and 4, the plate is shown in
two different positions. It will be appreciated that in
Figure 3, jacket portion 66a, i.e., the upper portion, is
much longer than the lower portion 66, whereas in Figure 4,
the upper portion 66a is much shorter than the lower
portion 66.
The hoses required to operate the intensifier
22 of this embodiment comprised power fluid supply and
return hoses 74 and 76, and a jet fluid supply hose 78.
Hoses 74, 76, and 78, are connected to respective
pipes, indicated as 74a, 76a, and 78a (Figures 1 and 3).
Conduits 74a and 76a axe connected to power fluid
pump 16, and a suitable power fluid reservoir may be
; provided (not shown) in a manner well known in the art.
Conduit 78a is connected preferably via a suitable
filter 79 to a supply of ~et fluid, typically water,
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~ ~ preferabiy via a suitable filter (not shown).~
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Connections are made, as indicated in phantom in
Figure 5, between the hoses 74, 76, and 7~, to
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rigid conduits 74b, 76b, and 78b (Figure 5) connected from
plate 48 to intensifier 20. '!
The portions of the conduits extending between the
plate 48 and the hoses 7~, 76 and 78 are shown merely in
phantom for the sake of clarity.
Intsnsifier 20 may be of a known design, having a
plurality, in this case four, working cylinders and a
corresponding number of intensifier cylinders. Working
pistons operating in the working cylinders are connected to
intensi~ier pistons in intansifier cylinders. The working
pistons are supplied with hydraulic fluid via a valve at a
first pressure, e.g., 2,000-3,000 psi.
The intensi~ier pistons are supplied with a jet ~luid
at a second pressure, e.g., 60-100 psi.
The intensi~ier pistons have a diameter less than
that of the working pistons. Power ~luid, in this case
hydraulic fluid, is supplied to the working pistons in
sequence, and the pressure of the hydraulic fluid is
conveyed to the jet fluid in the intensifier cylinder at an
intensified or third pressure.
The high pressure jet ~luid is discharged from the
intensifier through a rigid jet conduit 82 to a jet nozzle
84.
As best shown in Figure 5, the jet nozzle 84 is
located in a plate 86, supported on a support arm 88, which
is in turn mounted on the plate 48.
In an alternate embodiment, means may be provided to
- exhaust the air between the web, and the plate. Such
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~031~3~2
means, a~ shown generally as 22a in Figure 6, may comprisethe vacu-lm plate 90, mounted on side walls 92, which are,
in turn, mounted on a back place 94 and which define a
hollow interior. Vacuum plate 90 i5 located to extend from
upstream to downstream of the jet 84, having regard to the
direction of web travel.
Vacuum plate 90 is provided with a plurality of air
passageway means 96, through which air may be withdrawn.
Air is exhausted therethrough by means of a fan 98 and a
motor 100, and is vented to atmosphere through discharge
opening 102.
Electrical power is supplied to the fan motor 100
by any suitable cable connection means 104 supplied through
the hose support 66 and arm 88.
The design and construction of the intensifier is not
illustrated, sinca it is believed that such intensifiers
may be made in a variety of different designs. Examples of
the intensifiers of this general type may be seen in
various patents, such as U.S. Letters Patent 2,243,978
entitled Rotary Hydraulic Intensifier, and U.S. letters
patent 2,876,704 entitled Hydraulic Transformer.
In operation, during the normal running o~ the paper
making machine, the rollers R1 and R2 will be rotating at
high speed, and the web will be moving in the direction of
the arrow "a", at up to six thousand feet per minute for
example.
In this situation, during normal operation, the
carriage 14 will be stored at Point P1 (Figure 7) at one
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end of the support bar 12.
Upon the occurrence of a break in the web downstream
of roll R2, the motor 62 is operated to drive the carriage
14 along bar 12, to a po.int P2 close to the edge o~ the
web, as shown in Figure 7. This point P2, at which the
carriage 14 will stop, may be approximately three inches in
from the edge of the web. The motor 18, at this point,
operates pump 16, supplying hydraulic ~luid typically at a
first pressure, for example, 3,000 psi, to the intensifier
20.
At the same time, jet fluid, such as water, is
supplied via a hose 78 to the intensifier 20 at a second
pressure o~ between 60-100 psi. The operation of the
intensifier will cause a high pressure jet to be emitted
from nozzle 84, typically at a nominal third pressure of
around 15,000 to 20,000 psi~ -:
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Just so long as the carriage 14 remains stationary in
this position, the jet will cut a continuous longitudinal
cut, indicated as "C1" (Figure 7) to form the tail T on the
web W.
: The cut, and tail, will of course be much longer than
that shown in Figure 7.
When a sufficiently long tail has been cut to enable
it to be rethreaded downstream o~ roll R2, in a manner
known per se, the motor 62 is then operated so as to cause
carriage 14 to traverse across the web to the point P3,
as shown in Figura 7. Since the web ls moving at high
`~ speed, this traverse movement will produce a diagonal or
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oblique cut, indicated gener~lly as "c2". In practice, the
angle of the diagonal cut will be more gradual than that
indicated in Figure 7. This will then cause the entire web
to be rethreaded through the stations downstream of
: roll R2, so that winding up of the paper can then continue.
After a predetermined time delay, typically for
example, two seconds, at the point P3, the supply of
hydraulic fluid is shut off, and the supply of jet fluid is
cut off, thereby terminating the emission of the cutting
jet from nozzle 84. The carriage 14 is then traversed back
along the bar 12 back to the point P1, where it is "parked"
ready for the next operation.
- In the us~ oP the Figure 6 embodiment, air is
withdrawn from between the web W, and the nozzle 84. This
is achieved by operating the motor 100 and fan 98, while in
: the position P2, and while the intensifier and carriage are
being traversed across the web to the position P3.
: . The operation of the fan 9;8 will cause induction of
air through the opening means ~9~ around the nozzle 84. . :~
Such air will be ejected through the opening 102.
: ~his will tend to cause the web W to cling more
closely to the nozzle 84, and thus, produce a cleaner cut.
The foregoing is a description o~ a preferred
embodiment of the invention which is given here by way of
example only. The invention is not to be taken as limited
to any of the specific features as described, but
comprehends all such variations thereo~ as coming within
~ the scope of the appended claims~
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