Note: Descriptions are shown in the official language in which they were submitted.
IMPROVED F~AME CONSTRUCTION AND MET~OD IN A _APER
MA~HINE PRESS SECTION FOR FACILIT~TING REPLACF.MENT
OF PRESS ROLLS AND FAB~ICS
The present invention relates to a method in a
compact press section of a paper machine which includes
a compact press roll combination, the rolls of which
form at least two press nips with each other through
which a paper web runs, by which method the fabrics in
the press section and/or the press rolls of the compact
press roll combination can be easily replaced. The
method is applied in a frame construction for the press
section which includes, in the direction of the run of
the paper web, a front frame situated before the roll
combination and a rear frame situated after the roll
combination, in which method the space above the roll
combination and between the front frame and rear frame
is opened by pivoting an intermediate frame arrangement
into an open position to form an open space which can be
used either directly or indirectly to facilitate
raplacement of at least the pick-up fabric, or
equivalent, and of the upper fabric, if any, of the
press and/or the replacement of one or more press rolls
of the roll combination.
The invention also relates to a frame construction
in a compact paper machine press section suitable for
use in the practice of the method. The Erame
construction is for a press section which includes a
compack press roll combination whose press rolls form at
least two and preferably three or more press nips with
each other, between which a paper web is adapted to run
in a lonyitudinal machine direction, preferably as a
closed draw, and press fabrics passing through the nips.
The press section comprises, in the direction of web
run, a front frame situated before the compact press
roll combination and a rear frame separate from the
front frame and situated after the roll combination.
The front and rear frames are interconnected by means of
an intermediate frame arranyement situated above the
,
roll combination and which is movable from a closed
position to an open position by actuating means to
create an open space above the press roll combination
so that a~ least one of the press roll and press fabrics
can be removed and replaced through the open space when
the intermediate frame arrangement is in the open
pOSitiOI~.
In the frame construction of conventional compact
press sections of paper machines, such as in the SYM-
PRESS* paper machine press section available from Valmet
Oy of Finland, front and rear frames are provided before
and after the compact press roll combination which are
permanently connected to each other by horizontal beams
located at both the operating and service sides of the
paper machine. As used herein, "front frame" means the
frame part that is situated before the compact press
roll combination in the direction of web run through the
press section and on which the upper press roll,
conventionally a suction roll, of the first press nip is
usually mounted. Correspondingly, "rear frame" means
the frame part which is situated after the press roll
combination.
Conventional frame constructions for compact paper
machine press sections present difficulties in
connection with the replacement of the press fabrics and
press rolls. These problems have become more serious as
the widths of the paper machines have increased since
the press rolls are longer and heavier. Moreover,
additional problems have been created by the increasing
use of press fabrics formed oE plastic materials. When
~ormed of plastic, the press fabrics tend to be
substantially rigid in the transverse direction which
prevents the press fabrics from being compressed into a
small volume, since this would cause the fabrics to
become wrinkled and therefore not usable.
* Trademark
.
In an attempt to overcome the problems described above,
Beloit Corporation of 8eloit, Wisconsin bas suggested a frame con~
struction, designated as its "flip-top~ construction, wherein either
the top part of the front frame or the top part o~ the rear frame can
be opened by rotating it about a pivot shaft whose axis is parallel
to the transverse direction of the paper machine and which is situ-
ated above the press rolls. As a consequence of this construction,
the two top parts of the frames cannot be opened at the same time.
In order to replace the pick-up fabric of a press section
incorporating a "flip-top" frame construction, which fabric usually
functions as the press fabric in the first and second press nips, the
top part of the front frame is opened. During this procedure, how-
ever, the top part of the rear frame must be locked since the top
part of the front frame, when opened, is supported on the top part of
the rear frame. In a corresponding manner, the top part of the rear
frame can be opened, such a~ in connection with the replacement of
the press fabric in the third press nip, only when the top part of
tbe front frame is closed and locked in position. The lower fabric
of the first nip, which runs mainly in the basement space, is re-
placed by means of conventional arrangements.
The "flip-top" frame construction described above can be
characterized as a type of "drawbridge" which is openable at an
articulated joint which is situated in the middle of the drawbridge
directly above the conpact roll combination and wherein only one-half
of the bridge can be opaned at any one time.
In applicant'a US-p~tent 4608~25
a method and press aection foc applying the
method are disclosed in which a space sit~lated above the press roll
combination and between the front and rear framea is opened or open-
able by pivoting an intermediate frame into an open position. The
-3-
pivoting is performed around an articulated joint
associated with the rear frame at the side of the roll
combination and the open space is utilized, directly or
indirectly, in the replacement of at least the pick-up
fabric and the upper fabric of the press and/or in the
replacement of one or more press rolls of the roll
combination.
The present invention is directed towards the
provision of an improvement in the method and apparatus
disclosed in applicant's U.S. Patent No. 4,608,125, and
to provide an alternative method and press section frame
construction for applying the method. The present
invention is also directed towards the provision of a
frame construction of a press section which can be
opened in a more simple and rapid manner than that of
the Beloit "flip-top" construction.
In accordance with one aspect of the present
invention, the intermediate frame arrangement in the
paper machine press section described above comprises a
front intermediate frame pivotally mounted to the front
frame by first pivot means having an axis transverse to
the longitudinal machine direction, a rear intermediate
frame pivotally mounted to the rear frame by second
pivot means having an axis transverse to the
longitudinal machine direction, intermediate frame part
located between the front intermediate frame and the
rear intermediate frame, and means for attaching the
front and rear intermediate frames to the intermediate
frame part when the intermediate frame arrangement is in
its closed position.
First actuating means is coupled to the front
intermediate frame for pivoting the same between closed
and open positions and second actuating means is coupled
to the rear intermediate frame for pivoting the same
between closed and open positions, whereby the front and
rear intermediate frames are separately openable and
closeable independent of each other.
In another aspect of the present invention, there --
is provided a method for replacing one or more press
;
rolls and/or press fabrics in a paper machine press
section having a compact press roll combination
including thx~e press rolls which form at least two
press nips with each other between which a web is
adapted to run in a longitudinal machine direction and
press fabrics passing through the press nips, the press
section further including a frame construction on which
the press rolls are mounted including a front frame
situated before the roll combination in the direction of
web run through the press section and a rear frame
situated after the roll combination in the direction of
web run through the press section, the frame
construction having a service side and an operating
side. The method comprising the steps of providing an
openable space above the compact press roll combination
by arranying an intermediate frame arrangement between
the front and rear frames, the intermediate frame
arrangement including a front intermediate frame having
inner and outer ends and pivotally mounted to the front
frame at the inner end thereof by first pivot means
having an a~is transverse to the longitudinal machine
direction, a rear intermediate frame having inner and
outer ends and pivotally mounted to the rear frame at
the inner end thereof by second pivot means having an
axis transverse to the longitudinal machine direction,
and an intermediate frame part to which the outer ends
of the front and rear intermediate frames are attachable
to close the space, the front and rear intermediate
frames being pivotable to open positions independently
of each other to open the space; opening the space by
pivoting at least one of the front and rear intermediate
frames; and removing and replacing one or more press
rolls and/or press fabrics through the open space above
the roll combination.
The present invention differs from the method and
frame construction disclosed in applicant's U.S. Patent
No. ~,608,125, in that in accordance with the present
invention, the intermediate frame comprises two pivoting
parts, one of which is pivotally connected to the front
~ 6
frame and the other of which is pivotally connected to
the rear frame, and wherein the intermediate frame can
be attachad in the closed position by suitable means,
such as locking members, situated at the outer ends of
the pivoting intermediate frame parts, such locking
members being coupleable onto a suitable stationary
frame part which preferably ~omprises components
associated with the frames in which the journal bearings
of the center roll of the press are mounted.
Comparing the present invention to the "flip-top"
construction of ~eloit Corporation, the present
invention can be characterized as a "drawbridge"
construction which is openable about articulated joints
placed at both ends of the drawbridge so that, if
necessary, both halves of the drawbridge can be opened
at the same time into the open position thereby
rendering the construction simpler in construction and
use and openable in a more rapid manner.
A more complete appreciation of the present
invention and many of the attendant advantages thereof
will be readily understood by reference to the following
detailed description when considered in connection with
the accompan~ing drawings in which:
FIG. 1 is a side elevation view of a press section
of a paper machine in accordance with one embodiment of
the invention and illustrating the intermediate frame
arrangement in the closed position;
FIG. 2 is a side elevation view of the press
section illustrated in FIG. 1 illustrating the
replacement of press rolls while the intermediate frame
arrangement is in its open position; and
FIG. 3 is a side elevation view of the press
section illustrated in FIGS. 1 and 2 and illustrating
the replacement of the pick-up and press felts of the
prsss section.
Referring now to the drawings wherein like
re~erence characters designate identical or
- correspondlng parts throughout the several views, the
press section shown in FIGS. 1, 2 and 3 comprises a
6a
closed press roll combination including rolls 13, 16,
21 and 31 which together form three successive pxess
nips N1, N2 and N3 between them. The press section also
includes a fourth, separate press nip N4 Eormed between
press rolls 33 and 43 (FIGS. 2 and 3).
' l
,
The press section includes first and second fabrics (uYually felt~)
10 and 20 which run through the first press nip Nl. The first
fabric 10 acts as a pick~up fabric and al.~o as a prass fabric in the
second press nip N2. A third press fabric 30 runs through the
third press nip N3 and a fourth pres~ fabric 40 comprises a lower
press fabric and passes through the fourth press nip 4.
A pick-up coll 11 is ituated within the loop of the fir~t
fabric 10. Pick-up roll 11 ha~ a suction zone whlch acts to transfer
the web fro~ the forming fabric 27 onto the run between rolls 11 and
13. Fabric 10 is guided by guide rolls 120 The run of second fabrlc
20 is guided by guide rolls 22 while the run of the third fabric 30
is guided by guide rolls 32. The fourth fabric 40 acts to shift the
web W from the point facing the transfer roll 18 into the last press
nip N4 and is guided by suction-transfer rolls 41 and 42 as well as
by guide rolls 42'.
The run of the web W from the pick-up point P through the
press section iB a~ follow~. The suction sector of the pick-op roll
11 detaches tbe web W fro~ the wire 27 and attache~ it onto the
bottom face of the fabric 10 on which the web W passes through the
twin-fabLic nip Nl. The lower roll 21 of nip Nl is provided with
a hollow face 21'. After the nip Nl, the web W follows the f~sst
fabric under the effect of suction ~ector 13a of suction roll 13. In
the second nip N2, the web W ls transPerred onto the smooth face
16' of center roll 16 on whlch it is carried lnto the third nip N3
after which the web W follows the center roll 16 and is then guided
by transfer roll 18 onto the fabric 40 within the suctlon sector of
the suct.ion roll 41 and further onto the other suction roll 42. The
web i8 supported by the fabric 40 as lt enters the last nip N4.
-7-
~ 7~
The construction and operation of the press section
described above are generally known and are desGribed herein merely
by way of background for the inventlon and as an example of one type
of compact press ~ection with whlcb the pre~ent invention can be
utillzed.
The method and frame construction of the invention can also
be applied in a compact pre~s section in which the web ha~ open draws
and it is understood tbat the press rolls can be mounted and in-
stalled in a manner different from that shown in the drawings.
The frame construction of the pres~ section inclQdes a front
frame 50 to the top portion of which an auxiliary frame 51 is pivot-
ally mounted by means of articulated joint3 52 having a horizontal
pivot axi~. The guide rolls of the fir~t fabric 10 are mounted on
the auxiliary frame 51. One of the guide rolls i8 mounted on a ten-
sioning device 54 in order to provide suitable tensioning of fabric
lOo The front frame 50 is provided with intermediate pieces 35 and
55 which can be opened for replacing the first fabric 10.
In accordance with the invantion, the frame construction in-
cludes a rear frame 70 to the front side of which a rear intermediate
frame 60b ls pivotally connected by means of a projecting part 71 ~o
as to pivot about horizontal pivot ~hat~ 62b. The rear intermediate
rame ~Ob i9 situated partly above the compact roll arrangement 13,
16, 21 and 31. The center roll 16 of the press i~ journalled about a
fixed axis of rotation on lt~ own frame part 19.
As seen ln FIGS. 2 and 3, both the operation and secvice
~ides of the front frame 50, the auxillary frama 51, and the lower
frame are lnterconnected by cantilever beams 110, 111 and 114 which
are ~upported at one end by traction member~ (not shown) on the lower
beam. The plane of the Eloor of the paper machine building is desig-
nated 501.
-8-
As ~een in FIG. 1, the intermediate frame arrangement 60 com-
prise~ two part~, namely a front intermediate frame 60a and the rear
lntermediate rame 60b. The front intermediate frame 60a i8 pivot-
ally linked to the front frame 50 by mean~ of hori~ontal articulated
joints 62a. The front intermediate frame 60a i~ pivoted around the
horizontal shafts 62a by actuating means 64a'. The front intermedi-
ate frame 60a comprises substantially V- or L- ~haped lateral part~
which are attached by means of a connecting part 65a to an intermedi-
ate part 60c of the inte~mediate frame srrangement 60. The intermedi-
ate part 60c is itself attached to bearing housings 17 fixedly mount-
ed to the frame part 19 of the center roll 16 of the press. Inter-
mediate frame parts l4 are attached to the front intermediate frame
60a by means of horizontal articulated jointq lS and the suction roll
13 o~ the press is mounted on the intermediate frame parts 14. The
intermediate frame parts 14 can be pivoted relative the front inter-
mediate frame 60a by means of power units 14a which also serve to
apply a load in nips Nl and N2.
- Still referring to E'IG. 1, the rear intermediate fra~e 60b
of the intermediate ~rame 60 i8 pivotally linked to the projecting
partJ 71 of the rear frame 70 by mean~ of horizontal artlculated
joints 62b and can be opened and clo~ed by actuating means 64b. The
press roll 31 is journalled on the rear intermediate frame 60b by
means of the frame part 67b to form the third press nip N3 with
center roll 16. The pre3s roll 31 can be ~hifted to the open posi-
tion 31' relative to the rear intermediate frame 60b by power units
58b which also serve to apply a load in nip N3. The side beams of
the rear intermediate frame 60b are substantially ~-shaped (when
viewed from the slde) and are attached to the ~tationary intermediate
frame part 60c of the intermediate ~rame 60 at their endq opposite to
the points of articulation 62b by mean~ of a connecting part 65b when
the intermediate fra~e 60 is in the closed position.
The intermediate frame arrangement 60 described above and
shown in FIG. 1 thu4 comprise~ two frame parts 60a and 60b in addi-
tion to a stationary part 60c which inte~connects the ~ame and can be
opened and closed for the purposes described above.
Replacement of the rolls of the pre~s section in accordance
with the method of the invention is illustrated in FIG. 2. The upper
au~iliary frame 51 of the front frame 5~ is pivoted around the pivot
qhaf~s 52 into the open position 51' by opening the ioints 53a, 53b.
The auxiliary frame 51 may also be stationary in wbich case it be-
comes cantilevered when the fabric 10 is replaced. In the case where
the auxiliary frame 51 is pivotable as shown in FIG. 2, it does not
have to be pivoted during replacement of a roll. Prior to replacing
the roll, the ~abric within the loop of which the roll to be replaced
is situated is removed. As shown in FIG. 2, lifting ropes 95 are
attached to the journals of the suction roll 11' to enable the 9UC-
tion roll to be liEted on the hooks 90 of a traverse crane. The
suction pick-up roll 11' i8 then replaced in a conventional mlnner.
Beore press roll~ 13, 16, 21 and 31 are lifted, the joints
65a and 65b o~ the intermediate frame 60a, 60b are opened and the
intermediate frames 60a, 60b pivoted from the closed position shown
in FIG. 1 to the vertical-open position 60a', 60b' shown schematic-
ally in FIGS. 2 and 3. In this manner a free space T having an open
top is created through which the lifting of the press rolls 13, 21,
16 and 31 can ~e accomplished.
The suction roll 13 of the compact press ~ection is
suspended from lifting cables 96 which are attach0d to the lifting
hook 91. Suction roll 13 i~ lifted upwardly and shifted to the side
--10--
of the press aection whlle at the same time turning it in space ~r.
Subsequently, the lower roll 21 of the first nip Nl is lifted in
the same way by mean~ o li~ting cables 96'. The suction roll 13 may
be lifted either by its axle journals by means of a pair of lifting
ropP~ or by a center~ ting technique by means of lifting lines.
When intermediate frames 60a, 60b are in the open positions
60a', 60b', the press roll 31 o~ the third press nip N3 can also be
replaced, alao by center-lifting, by means of lifting ropes or line
98 attached to lifting hooks 93. Prior to replacing roll 31, roll
32c is shifted along the path designated a2 to a temporary holding
s1te 32a'. A~ter the third Pabric 30 has been removed or the tension-
ing roll for fabric 30 shifted to the holding site 32a', a free space
Tl is opened above the Pourth press nip N4. Space Tl is opened
at lts upper end so that the press rolls 33 and 43 can be li~ted by
center-lifting. In accordance with FIG. 2, the press roll 33 is
lifted by lifting lines 99 attached to lifting hooks 94 while the
lower roll 43 is lifted by lifting lines 99'.
The term acenter-lifting~ as used above means that the rolls
are suspended from a single crane hook supported by lifting lines
which support the roll in a downwardly opening inverted V-shape sym-
metrically at both sides of the vertical central plane. The center-
lifting technlque has the advantage that the roll can be pivoted in
the horizontal plane around its vertical central axla which facili-
tates the shiPting of the rolls even in crowded conditions. On tbe
other hand, where a roll i~ lifted by its axle journals, the longi-
tudinal dlrection oP the roll usually remains fixed ~ince the opera-
tion oP two cranes in cooperation is a difPicult and dangerous
procedure.
The replacement or ~ervicing of roll~ 11, 13, 21, 31, 33 and
43 ha~ been dascribed abo~e in ~onnection with FIG. 2. In prac~ice,
however, it i8 usually the case that only a 3ingle roll requires re
placement or serviclng at any one time ln which ca~e only ~he neces-
~ary fabrlcs are removed and the neces~ary frame parts opened.
Re~erring to FIG. 3, the replacement of all of the fabrics
10, 20, 30 and 40, i~ illustrated. It i8 understood, however, that
it is not alway~ the caRe that all of the fabrics are replaced a~ the
same time. In the replacement of the firqt fabric 10, the auxiliary
frame 51 of the front fra~e 50 is pivoted about shaft 52 to the open
position Sl' or, in the case where the auxiliary frame 51 is station-
ary, it is cantilevered and the tensioning roll for fabric 10 support-
ed on the part 5g of auxiliary frame 51 is shifted to the holding
site 12a' along the path designated by arrow al.
In the replacement of the first fabric 10, the suction roll
13 is shifted to the side position 13' by pivoting the intermediate
frame 60a to the vertical-open po~ition 60a' and the lntermediate
pieces 35 and 55 of the front frame 50 at the service side of the
machine are opened so that open gaps V are formed in the frame
through which gaps the felt loop 10' i~ passed. In the replacement
of the second fabric 20, the suctlon roll 13 is shifted to the side
position 13', the press roll 21 i8 moved to the lower posltlon, and
the intermediate pieces 25 and the frame 26 are opened.
In the replacement of the third fabric 30, the intermediate
pieces 72 and 73 are opened and the tensioning roll for fabric 30 is
shifted along the path a3 to the holding site 32a' located above
the rear frame 74. The intermediate frame 60b i~ pivoted into the
open position 60b' while at the same time the press roll 31 and the
-12-
guide rolls 32c and 32d (EIG. 1) are also pivoted into
the inner positions whereby the open space T is forme~
to acilitate replacement of fabric 30.
In the replacement of lower fabric 40 of the fourth
press nip N~, the intermediate pieces 72, 74, 75 and 45
as well as nip N~ are opened, whereby the replacement of
the fourth fabric 40 may be accomplished through the
open top space Tl.
The roll of felt 400 is pushed along a rail (not
shown) which is situated in the space between the
intermediate pieces 72 and 74 of the machine.
Referring to FIG. 3, the roll 100 of the first
fabric which is supported on a pole carried by lifting
wires 101 is carried to the service side of the paper
machine. A loop 10' is unwound from roll 100 which is
then passed through the spaces V and through the open
press nips Nl and N2 to its operating position around
the cantilever beam 111 whereupon the roll 12a' is
shifted to its operating position and then auxiliary
frame 51' pivoted into the closed position with its
joints 53a, 53b being fastened.
In the replacement of the second fabric 20, the
roll 200 of the second fabric wrapped around a pole
carried by wires 201 is brought to the side of the paper
machine whereupon a loop 20' is unwound from roll 200
and passed through the open spaces V and through the
opened first nip N1 to its operating position around the
cantilever beams. Preliminarily, the tensioning and
alignment rolls o~ the fabric 20 which are situated in
the basement space below the floor level 501 are shifted
to the upper position below roll 21 to the level of the
cantilever beams 114, such as by means of apparatus of
the type disclosed in Canadian Patent No. 1,1~3,376. At
this point, the pole supporting the roll 200 is shifted
on its carrying wires 201 towards the space T in the
position shown in FIG. 3 whereby the second fabric 20
becomes positioned in its operating position around the
cantilever beams 114 when the nip N2 is opened to a
sufficient extent.
.
14
In the replacement of the third fabric 30, a loop
30' is unwound from a roll 300 wound around a pole
carried by wires 3010 The loop 30' is passed through
the spaces V around the various rolls 31, etc., situated
around the cantilever beams 1~3.
In the replacement of the fourth fabric 40, a
technique similar to the replacement of fabric 20 is
utilized so that when the fourth nip N4 is in the open
position, a loop ~0' of fabric is passed from the roll
400 carried by wires 401 around the cantilever beams 115
in the manner shown in FIG. 3.
The operations carried out in connection with the
replacement of the various felts and rolls are disclosed
in U.S. Patent No. 4,608,125.
In the manner described above, the fabrics 10, 20,
30 and 40 can be replaced by a procedure which is more
advantageous than in the prior art so that during
replacement of the fabrics, adequate space is available
for the various operations, primarily as a result of the
frame parts 60a and 60b being openable to a position
most favorable for replacement of fabrics. The frame
parts 60a and 60b can be opened simultaneously or,
alternatively, only one of them can be opened at any
time, as required.
It is seen from FIG. 3 that at least partly due to
the method and frame construction of the present
invention, the rolls to be situated inside the loops of
the fabrics which are replaced can be situated in a very
small space close to each other so that the free loop to
be unwound from the fabric rolls and which is fitted
around the
.
7~
various rolls and cantilever beams can be made relatively small and
preferably substantially drop-shaped which facilitateQ the insertion
of the fabrics. Regarding the replacement of fabrics, the method in
accordance with the invention is advantageous where the fabrics are
made of pla~tic which cannot be wrinkled to a bundle in the lat~ral
direction.
A3 noted above, the invention can also be applied to press
sections of other configurations than that specifically shown and
described herein. For example, the invention can be applied to press
sectlons avialable from applicant's assignee, Valmet Oy of Finland,
under the trademarks SYM-PRESS I and SYM PRESS II, the former having
only two press nips, i.e., press nips Nl and N2, and no separate
nip N4, the latter having three nips Nl, N2 and N3 without any
separate nip N~. In 3uch cases, either the third and the fourth
fabrics or the fourth fabric, respectively, are omitted.
Obviously, numerous modifications and variations of the
pcesent invention are possible in the light of the above teachings.
It is therefore to be undarstood that within the scope of the claims
appended hereto, the invention may be practiced otherwise than as
specifically disclosed herein.
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