Note: Descriptions are shown in the official language in which they were submitted.
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SHOE PRESS MECHANISM OF PAPER MACHINE
BACKGROUND OF THE INVENTION
The present invention relates to a shoe press
mechanism of a paper machine, and more specifically to a
shoe press mechanism of a paper machine that can stably
make paper and lengthen the life span of an annular belt
by tightening the annular belt which runs while the inner
periphery thereof comes in slide contact with a press shoe.
In a shoe press mechanism, a press roll is disposed
so as to face a press shoe, and a nip portion is formed by
the press roll and the press shoe. An annular belt is
disposed so that the inner periphery of the annular belt
comes in slide contact with the press shoe. The annular
belt is pressed against the press roll by the press shoe
with a feeding felt . Then, as the press roll is rotated,
the annular belt is pulled by the contact frictional force
against the feeding felt. Accordingly, the annular belt
takes around the press shoe.
A shoe press mechanism, in which a tube-shaped guide
shell having a finished outer surface is disposed at the
inside of the annular belt to support the annular belt,
has been known as the conventional shoe press mechanism
having the above-mentioned structure (for example, see
Patent Document 1). The diameter of the guide shell is
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set smaller than that of the annular belt, and a gap is
formed between the annular belt and the guide shell. in
addition, a belt cover is disposed on the outside of the
annular belt so as to prevent the oscillation caused by
the running of the annular belt.
Furthermore, the press shoe is disposed on a
supporter so as to be freely oscillated, and a tube-shaped
press jacket is provided so as to surround the press shoe
and the supporter. In addition, mounting-aid strips are
fixed parallel to the supporter in the inside of the press
jacket (for example, see Patent Document 2).
[Patent Document 1] JP-A-56=37395
[Patent Document 2] JP-A-2-104791
The annular belt (that is, press jacket) is disposed
so as to surround the press shoe. Accordingly, as the
press roll is rotated, the annular belt runs so as to
circulate while the inner periphery of the annular belt
comes in slide contact with the press shoe. The annular
belt is an endless belt that includes a base member, a
reinforcing member, and a resin layer covering the base
member and the reinforcing member. The base member and
the reinforcing member are made of material, which hardly
elongate, such as polyamide and polyethylene terephthalate
(PET). The annular belt is heated at 20 to 70 °C during
the papermaking, and is pressed by the press roll and the
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press shoe at a pressure in the range of 100 to 1500 KN/m.
Further, pressure air is supplied to the inside of the
annular belt.
For this reason, as the papermaking operation is
performed, the annular belt tends to elongate in the MD
direction (Machine Direction) (that is, in the running
direction of a wet paper web) and in the CMD direction
(Cross Machine Direction) (that is, in the width
direction). In addition, the annular belt is pulled in
the MD direction by the rotation of the press roll, and
then is turned therearound. Accordingly, tensile force is
applied to the annular belt in the MD direction, and then
the annular belt elongates.
Actually, during the papermaking operation, the
vicinity of the middle portion of the annular belt in the
CMD direction (in the width direction) tends to more
easily elongate compared to the both end portions thereof.
This tendency is caused by the following reasons. The
reasons includes the variation in the width direction (in
the CD direction) of the pressure applied to the annular
belt by the press roll and the press shoe of CCR (crown
control roll), which have larger diameters at the middle
portions than those of both ends; temperature factors such
as the variation of the temperature of the wet paper web
in the press mechanism of the previous step and the
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variation of the heating temperature of the wet paper web
by a steam box, which is provided to improve the
permeability of the annular belt; and a dynamic friction
factor caused by the variation of the amount of
lubricating oil to be supplied to the annular belt.
As described above, the annular belt tends to
elongate in the MD direction during the papermaking
operation and thus the entire length thereof increases,
and the vicinity of the middle portion of the annular belt
in the CMD direction (in the width direction) tends to
elongate locally. All of the guide shell and the
mounting-aid strips, which are provided to guide the
annular belt or the press jacket by coming in slide
contact with the inner periphery of the annular belt or
the press jacket, are fixed to the supporter, and do not
have a function to adjust the tension of the annular belt
in accordance with the elongation of the annular belt or
the press jacket.
Accordingly, when the looseness occurs due to the
elongation of the annular belt or the press jacket, the
annular belt or the press jacket meanders or wrinkles are
occur locally on the annular belt or the press jacket. In
the extreme case, since a crack or abrasion of the resin
occurs, the annular belt may be broken down or it may be
difficult to make paper. In this case, it is necessary
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that the replacement of the annular belt taking a long
time be performed. The life span of the annular belt is
reduced due to the problem, and thus the efficiency of the
papermaking operation deteriorates. As a result, since
the cost of paper products increases, improvement of the
papermaking efficiency is radically required.
SUMMARY OF THE INVENTION
The invention is made in consideration -of the above-
mentioned problems, and it is an object of the invention
to a press shoe mechanism of a paper machine that can
easily adjust the tension of an annular belt and correct
the elongation of the annular belt occurring in the MD and
CMD directions during the papermaking operation, thereby
causing the annular belt to stably run with an adequate
tension.
In order to achieve the above-mentioned object, a
shoe press mechanism of a paper machine according to the
invention is characterized in the following (1), (2), and
(3) .
(1) A shoe press mechanism of a paper machine
includes a press roll; a supporter of which both ends are
fixed to a machine casing; a press shoe that is provided
to the supporter so as to move in the direction of
approaching or being separated from the press roll; a pair
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of supporting disks which is provided on both sides of the
press shoe so as to be rotatably supported by the
supporter, respectively; an annular belt which is disposed
so as to include the press shoe therein, of which both
ends are fixed to the pair of supporting disks, and which
runs while the inner periphery thereof comes in slide
contact with the press shoe; and an adjusting stay bar of
which both ends are fixed to the supporter so as to be
parallel to an axis of the annular belt. In this case, a
wet paper web to be fed by a feeding felt is nipped by the
press roll and the press shoe together with the annular
belt. Further, a mounting position of the adjusting stay
bar with respect to the supporter is adjustable, and the
tension of the annular belt is adjusted by adjusting the
mounting position.
(2) In the shoe press mechanism of a paper machine
of (1),
the adjusting stay bar is a straight bar, and the
mounting position thereof is adjusted in the radial
direction of the annular belt.
(3) In the shoe press mechanism of a paper machine
of (1),
the middle portion of the adjusting stay bar in the
axial direction is curved like a bow, and
the tension of the annular belt is adjusted in order
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to tighten the middle portion of the annular belt in the
width direction thereof by adjusting a rotational phase of
the adjusting stay bar with respect to the supporter, and
then by fixing the adjusting stay bar to the supporter.
According to the shoe press mechanism of a paper
machine having the structure disclosed in (1), a mounting
position of the adjusting stay bar with respect to the
supporter can be adjusted, and the tension of the annular
belt can be adjusted by adjusting the mounting position.
Accordingly, it is possible to constantly apply adequate
tension to the annular belt by adjusting the mounting
position of the adjusting stay bar in accordance with the
elongation of the annular belt. As a result, the life
span of the annular belt is lengthened and it is possible
to stably make the paper for a long time by solving
problems, for example, the occurrence of the meandering,
wrinkles or cracks of the annular belt caused by the
looseness of the annular belt.
According to the shoe press mechanism of a paper
machine having the structure described in (2), the
position of the straight adjusting stay bar can be
adjusted in the radial direction of the annular belt.
Accordingly, when the annular belt elongates in the MD
direction and thus the entire length thereof increases, it
is possible to tighten the annular belt in the MD
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direction, corresponding to its elongation and to apply
adequate tension to the annular belt, by causing the
adjusting stay bar to move outward in the radial direction
in order to adjust the position thereof.
According to the shoe press mechanism of a paper
machine having the structure described in (3), the middle
portion of the adjusting stay bar in the axial direction
thereof is curved like a bow. Accordingly, when the
middle portion of the annular belt in the width direction
elongates locally, the middle portion of the adjusting
stay bar in the axial direction thereof protrudes outward
in the radial direction by adjusting the rotational phase
of the adjusting stay bar with respect to the supporter,
and then the adjusting stay bar is fixed. As a result, it
is possible to adjust the tension of the annular belt in
the MD and CMD directions in order to the middle portion
of the annular belt in the width direction thereof.
According to the press shoe of the paper machine,
entire elongation of the annular belt and local elongation
occurring in the middle portion of the annular belt in the
width direction thereof disappears, and it is possible to
apply adequate tension to the annular belt by adjusting
the mounting position of the adjusting stay bar with
respect to the supporter, and by adjusting the rotational
phase of the adjusting stay bar with respect to the
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supporter. As a result, the life span of the annular belt
is lengthened and it is possible to stably make the paper
for a long time.
As described above, the invention is briefly
described. Furthermore, the detail of the invention will
be more clearly understood by describing a preferred
embodiment according to the invention to be described
below with reference to accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a longitudinal cross-sectional view
showing main parts of a shoe press mechanism according to
the invention.
Fig. 2 is a cross-sectional view taken along the
line II-II in Fig. 1.
Fig. 3 is a perspective view schematically showing
the main parts of the shoe press mechanism.
Fig. 4 is a side cross-sectional view showing a
state in which a radial position and rotational phase of
an adjusting stay bar are adjusted and then the adjusting
stay bars are fixed to a supporter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, a preferred embodiment according to the
invention will be described in detail with reference to
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drawings.
Fig. 1 is a longitudinal cross-sectional view
showing main parts of a shoe press mechanism according to
the invention, Fig. 2 is a cross-sectional view taken
along the line II-II in Fig. 1, Fig. 3 is a perspective
view schematically showing the main parts of the shoe
press mechanism, and Fig. 4 is a side cross-sectional view
showing a state in which a radial position and a
rotational phase of an adjusting stay bar are adjusted and
the adjusting stay bars are fixed to a supporter.
As shown Figs. 1 and 2, a shoe press mechanism 100
of a paper machine according to the invention includes a
shoe press 11, and a press roll 13 disposed so as to face
the shoe press 11. The shoe press 11 includes a supporter
15, a press shoe 19, a pair of supporting disks 21, an
annular belt 23, and a plurality of adjusting stay bars 25.
Both ends of the supporter 15 are fixed to a machine
casing (not shown) so that the supporter 15 is disposed
parallel to the press roll 13. A hydraulic chamber 27 is
formed on a surface (upper surface in Fig. 1) of the
supporter 15 facing the press roll 13. The press shoe 19
is fitted to the hydraulic chamber 27 so as to move in the
direction of approaching or being separated from the press
roll 13. Pressure oil is supplied from a pressure oil
supply device (not shown) to the hydraulic chamber 27 so
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that the press shoe 19 is pressed against the press roll
13 with a predetermined force.
A pair of supporting disks 21 is rotatably provided
in a pair of supporting members 17, which is fixed to both
ends of the supporter 15, respectively, by ball bearings
29. The ends of the annular belt 23 are fixed on the
outer peripheries of the pair of supporting disks 21 with
seal members 31 interposed therebetween, respectively.
That is, the supporter 15 and the press shoe 19 are
surrounded by the annular belt 23 and disposed at the
inside of the annular belt 23 so that the inner periphery
of the annular belt 23 comes in contact with the press
shoe 19. Accordingly, when pressure air is supplied from
a pressure air supply source (not shown) to the inside of
the annular belt 23, the annular belt 23 is expanded in a
cylindrical shape.
The plurality of adjusting stay bars 25 is fixed to
a pair of stays 33, which is fixed to the supporting
members 17, in the circumferential direction of the
annular belt 23 so as to be disposed in the vicinity of
the inner periphery of the annular belt 23. The adjusting
stay bars 25 come in slide contact with the inner
periphery of the annular belt 23 to support the annular
belt 23 from the inside thereof. In addition, a
lubricating oiI supply device 37 is provided in the stay
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33. The lubricating oil supply device supplies
lubricating oil on the inner periphery of the annular belt
23 during the running of the annular belt 23 in order to
reduce frictional resistance of the annular belt against
the press shoe 19. The lubricating oil lubricates the
annular belt 23, and then is drained through an oil drain
port 39 provided on the lower side of the supporter 15.
Both ends 13a of the press roll 13 are rotatably
supported by the machine casing and are coupled to a
driving unit (not shown) so that the press roll 13 is
driven by the driving unit so as to be rotated.
Next, the adjusting stay bars 25, and a mechanism
for fixing the adjusting stay bars 25 to the stays 33 will
be described. As shown in Figs. 3 and 4, an adjusting
stay bar 25A is formed in the form of a straight
cylindrical rod, and male thread portions 25a are formed
on both ends thereof, respectively. When the annular belt
23 elongates in the MD direction and thus the entire
length thereof increases, the adjusting stay bar is used
to adjust the tension of the annular belt 23. Mounting
holes 33a for the adjusting stay bar 25A are formed in the
pair of stays 33, and are formed in the shape of a slotted
hole elongating in the radial direction of the annular
belt 23, respectively.
The male thread portions 25a formed on both ends of
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the adjusting stay bar 25A are inserted into the mounting
holes 33a, respectively, and then the adjusting stay bar
is positioned in the slotted hole in the radial direction
(direction indicated by an arrow A or B) to adequately
apply tension to the annular belt 23. After that, the
adjusting stay bar is fixed to the stays 33 by nuts 35.
The adjusting stay bar 25A for adjusting the elongation of
the entire length of the annular belt 23 may be disposed
at least at one position among the plurality of adjusting
stay bars 25, which is disposed in the circumferential
direction of the annular belt 23 along the inner periphery
thereof. Furthermore, the position or the number of the
adjusting stay bar for adjusting the elongation of the
entire length of the annular belt is not especially
limited.
In addition, when the middle portion of the annular
belt 23 elongates in the width direction, an adjusting
stay bar 25B is used to adjust the tension of the annular
belt 23. The adjusting stay bar 25B is formed in the form
of a cylindrical rod of which middle portion is curved
like a bow, and male thread portions 25a are formed on
both ends thereof, respectively. Each of mounting holes
33b for the adjusting stay bar 25B, which is formed in the
stay 33, is formed in the shape of a circular hole having
the same diameter as each male thread portion 25a. The
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male thread portions 25a formed on both ends of the
adjusting stay bar 25B are inserted into the mounting
holes 33b, respectively, and then the adjusting stay bar
25B is rotated in the rotational direction indicated by an
arrow C or D to adjust a rotational phase of adjusting
stay bar. After that, the adjusting stay bar is fixed to
the stays 33 by nuts 35.
When the adjusting stay bar 25B is rotated in the
rotational direction indicated by an arrow C, the middle
portion of the adjusting stay bar 25B in the axial
direction thereof protrudes outward in the radial
direction. Accordingly, locally elongated in the width
direction, the middle portion of the annular belt 23 is
tightened, and thus adequate tension is applied to the
annular belt. The adjusting stay bar 25B for adjusting
the local elongation of the annular belt 23 may be
disposed at least at one position among the plurality of
adjusting stay bars 25, which is disposed in the
circumferential direction of the annular belt 23 along the
inner periphery thereof. Furthermore, the position or the
number of the adjusting stay bar for adjusting the local
elongation of the annular belt is not especially limited.
However, if the adjusting stay bar 25B is disposed in
front of the entrance side of the press shoe 19 in the
running direction of the annular belt 23, the annular belt
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23 is pre-tensioned by the adjusting stay bar 25B.
Accordingly, it is effective that the oscillation (that is,
the occurrence of the meandering or wrinkles of the
annular belt 23 caused by the elongation of the annular
belt 23) of the annular belt 23 can be controlled so as to
be fed between the press shoe 19 and the press roll 13.
The operation of the invention will be described. A
press mechanism (not shown) disposed in the upstream of
the shoe press mechanism 100 squeezes water from a wet
paper web, and the wet paper web is fed between the press
shoe 19 and the press roll 13 of the shoe press mechanism
100 together with a feeding felt (not shown). Pressure
oil is supplied to the hydraulic chamber 27, and then the
press shoe 19 is pressed against the press roll 13 with a
predetermined force. Accordingly, the wet paper web is
pressed by the press shoe 19 and the press roll ~13
together with the annular belt 23, and thus water is
further squeezed from the wet paper web. In this case,
when the torque of the press roll 13 is transmitted to the
feeding felt, the annular belt 23 not to be driven is
pulled by the contact frictional force against the feeding
felt. Accordingly, the annular belt is taken around the
pair of supporting disks 21, and then the annular belt 23
runs so as to circulate while the inner periphery of the
annular belt 23 comes in slide contact with the press shoe
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19.
In addition, the annular belt 23 is pressed by the
press shoe 19 and the press roll 13. Therefore, as the
papermaking operation is performed, the annular belt
elongates in the MD and CMD directions. The oscillation
of the annular belt 23, which is caused by the elongation
of the annular belt 23 during the running of the annular
belt, hinders the paper from being stably made to
deteriorate the quality of the wet paper web. Accordingly,
it is necessary that the tension be applied to the annular
belt 23 so as to cause the annular belt 23 to run stably.
The conventional shoe press mechanism does not have a
function to adjust the tension of the annular belt 23.
Accordingly, when the oscillation of the annular belt 23
is caused by the elongation of the annular belt 23 during
the running of the annular belt and thus the papermaking
operation is hindered, there is no countermeasure except
for the replacement of the annular belt 23. In the shoe
press mechanism 100 of the invention, it is possible to
easily adjust the tension of the annular belt 23 according
to the following procedure.
That is, when the annular belt 23 elongates in the
MD direction and thus the entire length thereof increases,
as shown in Figs. 3 and 4, the male thread portions 25a of
the straight adjusting stay bar 25A move in the mounting
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holes 33a, which are formed in the shape of a slotted hole,
in the radial direction (direction indicated by the arrow
A or B) to apply the tension to the annular belt 23 and
then the adjusting stay bar is fixed to the stays 33 by
the nuts 35. The above-mentioned operation is performed
as follows: The both supporting disks 21 are separated,
and then the tension of the annular belt 23 is adjusted.
After that the both supporting disks 21 are mounted.
Furthermore, if operation holes are formed through the
supporting disks 21 so as to correspond to the positions
of the mounting holes 33a of the stays 33, respectively,
it is possible to adjust the tension of the annular belt
without the separation of the supporting disks 21 whenever
the tension thereof is adjusted.
In addition, when the middle portion of the annular
belt 23 in the width direction elongates locally, the
adjusting stay bar 25B of which middle portion in the
axial direction is curved like a bow is rotated in each
mounting hole 33b in the direction indicated by an arrow C
or D to adjust the rotational phase thereof so that the
middle portion of the adjusting stay bar 25B in the axial
direction protrudes outward in the radial direction.
Accordingly, locally elongated in the width direction, the
middle portion of the annular belt 23 is tightened. Then,
the adjusting stay bar 25B is fixed to the stays 33 by the
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nuts 35.
Furthermore, when the annular belt 23 elongates in
the MD and CMD directions, the fixing positions of the
adjusting stay bars 25 to the stays 33 are adjusted as
described above. Accordingly, it is possible to apply
adequate tension to the annular belt 23 in order to
tighten the annular belt 23. As a result, the Life span
of the annular belt 23 is lengthened, and it is possible
to stably make the paper.
According to the shoe press mechanism 100 of the
invention, since the mounting positions of the adjusting
stay bars 25 to the supporter 15 can be adjusted, it is
possible to adjust the tension of the annular belt 23 by
adjusting the mounting positions of the adjusting stay
bars 25. Accordingly, it is possible to constantly apply
adequate tension to the annular belt 23 by adjusting the
mounting positions of the adjusting stay bars 25 in
accordance with the elongation of the annular belt 23. As
a result, the life span of the annular belt 23 is
lengthened and it is possible to stably make the paper for
a long time by solving problems, for example, the
occurrence of the meandering, wrinkles or cracks of the
annular belt 23 caused by the looseness of the annular
belt 23.
Moreover, according to the shoe press mechanism 100
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of the invention, the position of the straight adjusting
stay bar 25A can be adjusted in the radial direction of
the annular belt 23. Accordingly, when the annular belt
23 elongates in the MD direction and thus the entire
length thereof increases, it is possible to apply adequate
tension to the annular belt 23 by causing the adjusting
stay bar 25A to move outward in the radial direction in
order to adjust the position thereof.
According to the shoe press mechanism 100 of the
invention, the middle portion of the adjusting stay bar
25B in the axial direction thereof is curved like a bow.
Accordingly, when the middle portion of the annular belt
23 in the width direction elongates locally, the middle
portion of the adjusting stay bar 25B in the axial
direction thereof protrudes outward in the radial
direction by adjusting the rotational phase of the
adjusting stay bar 25B with respect to the supporter 15,
and then the adjusting stay bar 25B is fixed. As a result,
it is possible to adjust the tension of the annular belt
23 in the MD and CMD directions in order to tighten the
middle portion of the annular belt 23 in the width
direction thereof.
The invention is not limited to the above-mention
embodiment, and can have adequate modifications. In
addition, the material, shape, size, dimension,
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configuration, arrangement, and the number of each
component in the above-mentioned embodiment are set as any
values to achieve the invention, and are not limited
thereto.
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