U.S. patent application number 10/356223 was filed with the patent office on 2004-08-05 for apparatus for removing liquid from a press roll sleeve or belt on a paper making machine.
Invention is credited to Watson, Robert Bradley.
Application Number | 20040149414 10/356223 |
Document ID | / |
Family ID | 32770751 |
Filed Date | 2004-08-05 |
United States Patent
Application |
20040149414 |
Kind Code |
A1 |
Watson, Robert Bradley |
August 5, 2004 |
Apparatus for removing liquid from a press roll sleeve or belt on a
paper making machine
Abstract
A blade (20) for wiping water from a sleeve (26) mounted on a
press roll (14) in a paper making machine is adjustably mounted on
the machine for movement toward and away from the sleeve (26). The
wiper blade (20) is positionable against the surface of the sleeve
(26) to wipe water therefrom adjacent and upstream from the nip
between the sleeve (26) and a mating press roll (12).
Inventors: |
Watson, Robert Bradley;
(Natchitoches, LA) |
Correspondence
Address: |
WEYERHAEUSER COMPANY
INTELLECTUAL PROPERTY DEPT., CH 1J27
P.O. BOX 9777
FEDERAL WAY
WA
98063
US
|
Family ID: |
32770751 |
Appl. No.: |
10/356223 |
Filed: |
January 31, 2003 |
Current U.S.
Class: |
162/282 ;
162/281; 162/DIG.7 |
Current CPC
Class: |
D21G 3/005 20130101 |
Class at
Publication: |
162/282 ;
162/281; 162/DIG.007 |
International
Class: |
D21G 003/00 |
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A press roll system in a paper making machine comprising: a
press roll mounted in a framework; a surface-patterned sleeve on
the press roll; a wiper blade mounted on said framework, said wiper
blade having a blade edge positionable against the surface of said
sleeve; and, a trough positioned beneath said wiper blade.
2. The system of claim 1, wherein said press roll defines a nip
region, said wiper blade being positioned upstream of the nip
region.
3. The system of claim 1 wherein said blade is mounted for swinging
movement between a first position wherein said blade edge is
positioned in contact with the surface of said sleeve and a second
position wherein said blade edge is spaced from said surface.
4. The system of claim 1 wherein said wiper blade is mounted for
movement toward and away from said sleeve.
5. The system of claim 1 wherein said sleeve and said blade
comprise the same material.
6. The system of claim 8 wherein said material comprises
polyethylene.
7. The system of claim 1 wherein said surface-patterned sleeve
includes at least one of a surface groove pattern and hole pattern.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to paper making machines and,
more particularly, to press rolls employed in paper making machines
and, most particularly, to an apparatus for removing water from the
shoe press sleeve or belt in the press section of a paper making
machine.
BACKGROUND OF THE INVENTION
[0002] Paper, linerboard, and other sheet products produced from
cellulose fibers are produced in a paper making machine by
depositing an aqueous slurry of cellulose fiber containing various
additives from a head box on a fabric screen to form a cellulose
mat. Water is extracted from the slurry via vacuum boxes positioned
below the fabric leaving a mat or sheet of cellulose fibers on the
fabric. The mat is then transferred to a continuous press felt. The
felt and mat are then run to a first pair of nip rolls, commonly
referred to as a top press roll and a bottom press roll. Additional
water is extracted from the mat as it passes between the top and
bottom press rolls. A polyethylene sleeve or belt is mounted on one
of the press rolls, typically the top press roll. Circumferential
grooves are provided in the sleeve to allow the water being
squeezed from the mat to travel laterally and thus extract it from
the mat. Some of this water is removed from the grooves by the
centrifugal force created by the spinning top press roll.
[0003] However, it has been observed that water may still puddle
ahead of the nip between the press rolls. The presence of this
water detracts from the performance of the press rolls. It is
therefore desirable to reduce or eliminate the puddling that occurs
ahead of the nip between the press rolls. Heretofore, however, the
origin of the water that puddles ahead of the nip and how to remove
that water have not been fully understood.
SUMMARY OF THE INVENTION
[0004] It has now been recognized that despite removal of water
from the top press roll by centrifugal force, much water still
remains on the surface of the rolls and particularly in the
circumferential grooves in the sleeve. The present invention
removes this water from the surface and the grooves by providing a
means for wiping the surface of the grooved sleeve. This is
accomplished with a top press roll wiper blade mounted in a
bracket, which in turn is mounted on the paper making machine
framework. The wiper blade has an edge that is positioned in
contact with the surface of the sleeve upstream from the nip
between the top and bottom press rolls. As the top press roll spins
in the direction of the wiper blade and the nip, the wiper blade
removes water from the surface of the sleeve and, moreover, removes
water from the circumferential grooves in the sleeve. In a
preferred form of the invention, the wiper blade is mounted for
movement toward and away from the sleeve so as to allow for varying
the pressure of the wiper blade on the sleeve and for retracting it
from contact with the sleeve when it is not needed, or for repair
or replacement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated by reference
to the following detailed description, when taken in conjunction
with the accompanying drawings, wherein:
[0006] FIG. 1 is a schematic view of top and bottom press rolls in
a paper making machine along with a preferred form of the wiper
blades constructed in accordance with the present invention;
[0007] FIG. 2 is an enlarged side view of the wiper blade shown in
FIG. 1;
[0008] FIG. 3 is a top view of a segment of the wiper blade and
mounting mechanism shown in FIG. 2; and
[0009] FIG. 4 is an illustration of a top press roll, a wiper
blade, and a trough constructed in accordance with the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] Referring first to FIG. 1, the first set of press rolls 10
of a press section of a conventional paper making machine is shown
in phantom. The press section of a conventional paper making
machine may have more than one set of press rolls. The bottom press
roll 12 is usually mounted on the paper making machine framework
for rotation in a counterclockwise direction. The top press roll 14
is mounted for rotation in a clockwise direction. The top press
roll is conventionally mounted so that it can be moved up and down,
that is, toward and away, from the bottom press roll 12. A felt 18
forming part of the press carries a mat of cellulose fibers between
the nip 16 of the top and bottom press rolls. In this view, the
paper mat is omitted for purposes of simplicity. The top press roll
14 normally carries a sleeve (shown in FIG. 2 as 26) that carries a
plurality of circumferential grooves that assist in extracting
water from the mat of cellulose fibers being run through the nip 16
between the rolls 12 and 14. A wiper blade 20 constructed in
accordance with the present invention is mounted on a blade
mounting assembly 22, in turn mounted on framework 24 of the paper
making machine.
[0011] Referring now to FIGS. 2 and 3, the blade 20 is positioned
against the grooved sleeve 26 forming part of the top press roll
14. The blade 20 itself is an elongated member that is at least the
length of the sleeve 26. A cross-sectional profile shows the blade
coming to a sharp edge at the instance where it contacts the sleeve
26. The opposite edge of the blade is fixed to the mounting
assembly 22 as described further below. Although the blade is shown
as a straight edge, in other embodiments the blade edge may be
profiled to match the groove profile in the sleeve. For grooved
sleeves, the blade edge would then be provided with protrusions to
match the profile of the grooves. Groove profiles may be
trapezoidal, square, U-shaped, or any other profile. It is also to
be appreciated that other surface patterns besides grooves may be
machined on the sleeve. For example, a drilled pattern sleeve can
be used in place of a grooved sleeve. The blade assembly 22 has a
first section 30 that is pivotally attached to a second section 32.
Opposing flanges 34 and 36 extend from the first and second
sections 30 and 32, respectively, and are coupled together by a
pivot pin 38. The axis of the pivot pin 38 is substantially
parallel to the rotational axis of the top press roll 14. The blade
20 is secured in the first section 30 of the bracket by
conventional fasteners, such as bolts 40. The second section 32 of
the blade mounting assembly is affixed to an L-shaped bracket 42 by
a conventional fastener 44 such as a bolt. The L-shaped bracket 42
has an upright arm 42b and a generally horizontal arm 42a, which
rests on a horizontal surface 46 forming part of the main framework
24 of the paper making machine. The L-shaped bracket 42 is mounted
for movement toward and away from the press roll 14 in the
direction of arrows 48. A jack screw assembly 50 is employed to
adjust the position of the L-shaped bracket relative to the top
press roll 14. The screw 50a is rotatably mounted in flange 52
attached to framework 24. A threaded nut 50b is affixed to bracket
42. A lock nut 53 is employed to lock the screw 50a to the nut 52b.
The jack screw mechanism provides a gross positioning of the blade
mounting assembly 22 relative to the press roll 14.
[0012] The entire blade assembly and captive blade extend the
entire length of the top press roll 14. Only one end portion of the
blade 20 and mounting assembly 22 is shown in FIG. 3. Several of
the jack screw mechanisms 50 are placed at intervals along the
length of the blade mounting assembly. In a preferred installation,
it is preferred that the blade 20 be mounted less than about 90
degrees from the nip 16 of the top press roll 14.
[0013] The blade mounting assembly 22 also has a pair of bladders
54 and 56 mounted between the first and second sections 30 and 32
and above and below the pivot pin 38. The bladders are coextensive
in length with the blade mounting assembly 22. Selective inflation
of the bladders 54 and 56 allows the first section 30 to be pivoted
to and fro so that the blade 20 can be moved toward and away from
contact with the surface of the sleeve 26 and so that variable
pressure can be applied by the leading edge blade of the wiper
blade 20 against the surface of the sleeve 26. In other
embodiments, the bladders 54 and 56 can be replaced with other
equally suitable biasing devices, including leaf or coil springs.
In a preferred embodiment, the blade mounting assembly is
constructed so as to allow movement of the blade toward and away
from the surface of the sleeve 26 of the top press roll 14 from one
to two inches. The blade load may be adjusted so that loads on the
order of 0.2 pounds per linear inch (PLI) (36 grams per cm) can be
applied by the blade against the surface of the press roll sleeve
26.
[0014] In a preferred embodiment, the sleeve 26 of the top press
roll is preferably comprised of polyethylene. The grooves in the
sleeve 26 are conventionally machined into the surface of the
polyethylene. It is also preferred that the blade 20 also be made
of polyethylene. Thus, when the blade is brought into contact with
the press roll sleeve 26, a minimum of frictional wear is created.
Without the wiper blade of the present invention, the sleeve
appears to be free of water. However, when the blade is positioned
against the sleeve, substantial amounts of water are removed.
Measurements have shown that on the order of an additional 66
gallons of water per minute are removed from a sleeve in the press
section of a paper making machine running at an overall output of
58 tons per hour of paper. This results in substantial overall
energy savings in the paper making process because the amount of
water that is removed from the sleeve is not required to be
evaporated from the fiber mat at a later stage.
[0015] Referring now to FIG. 4, one embodiment of the present
invention is illustrated, whereby a trough 50 is located below the
blade 20. The trough has a lower base 56 surrounded by peripheral
walls 58, thus forming a collection basin for water that may run
off from the outboard side of the blade 20. The water is indicated
by arrows 52. The trough 50 has sufficient width to also collect
water that may run off from the inboard side of the blade 20, said
water run off being indicated by arrow 54. Lengthwise, the trough
50 is at least as long as the blade 20. The trough 50 has
sufficient volume to contain the expected water collection from the
sleeve surface 26 and the sleeve grooves 26a. The trough 50 is
inclined, meaning that one end of the trough is at a higher
relative position than its opposite and lower end. At the lower
end, a pipe 60, or other suitable conduit, may be connected to
channel away the collected water from the roll. The trough 50 may
be positioned at any location below the blade 20. However, in one
embodiment, the trough is located below the machine framework 24.
In this manner, any water that is collected from the sleeve 26 and
the sleeve grooves 26a may be captured and discarded from the
process.
[0016] The invention may be incorporated into any paper making
process that produces paperboard, linerboard, and/or any other
sheet products produced from cellulose fibers that are formed into
a fiber mat. The process includes depositing an aqueous slurry of
cellulose fiber containing various additives from a head box onto a
fabric screen to form a cellulose fiber mat. Water is extracted
from the slurry via vacuum boxes positioned below the fabric screen
leaving a fiber mat or fiber sheet of cellulose fibers on the
fabric. Paper making machines having a press roll system often
include more than one pair of nip rolls. After forming, the fiber
mat or sheet is then transferred to a continuous press felt. The
felt and the mat are run through the press roll system to a first
pair of nip rolls. The nip rolls are also referred to as a top
press roll and a bottom press roll. As mentioned previously, the
press roll system can include a plurality of pairs of nip rolls.
Water is further extracted from the fiber mat or sheet as it passes
between the pairs of top and bottom press rolls. The present
invention can be incorporated into any one top or bottom press roll
or both and in one or more pairs of press rolls in the press roll
system. Any roll that is provided with a surface patterned sleeve
can be modified to incorporate the wiper blade in accordance with
the present invention. The water is removed from the fiber mat or
sheet by the wiper blade assembly in accordance with the invention,
thus producing a fiber mat of reduced water content before further
processing, meaning less water than would ordinarily be expected
will need to be evaporated from the fiber mat or sheet.
[0017] While the preferred embodiment of the invention has been
illustrated and described, it will be appreciated that various
changes can be made therein without departing from the spirit and
scope of the invention. For example, one of ordinary skill will
recognize that, alternatively or in addition, a grooved sleeve can
be mounted on the bottom press roll. A wiper blade constructed in
accordance with the present invention can be positioned to contact
such a sleeve upstream from the nip and remove water from the
sleeve so positioned.
* * * * *