US20030015306A1 - Extended-nip press - Google Patents

Extended-nip press Download PDF

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Publication number
US20030015306A1
US20030015306A1 US10/186,421 US18642102A US2003015306A1 US 20030015306 A1 US20030015306 A1 US 20030015306A1 US 18642102 A US18642102 A US 18642102A US 2003015306 A1 US2003015306 A1 US 2003015306A1
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US
United States
Prior art keywords
piston
cylinder
press
extended
roll
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/186,421
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English (en)
Inventor
Erkki Aho
Aki Laari
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vaahto Paper Technology Oy
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Assigned to VAAHTO OY reassignment VAAHTO OY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AHO, ERKKI, LAARI, AKI
Publication of US20030015306A1 publication Critical patent/US20030015306A1/en
Abandoned legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00—Press section of machines for making continuous webs of paper
    • D21F3/02—Wet presses
    • D21F3/0209—Wet presses with extended press nip
    • D21F3/0218—Shoe presses

Definitions

  • the present invention relates to an extended-nip press according to the preamble of the appended base claim.
  • an extended-nip press comprises a press roll cooperating with a backing roll.
  • the press roll comprises a rotating endless-loop blanket of a flexible, liquid-impervious material, a rigid and advantageously stationary roll support beam that extends axially through the interior of the endless blanket, at least one press shoe resting on the roll support beam and having a concave top face, and loading means for loading the shoe so as to press the concave top face thereof against the flexible endless blanket in order to form a press nip zone in cooperation with the backing roll, whereby the loading means comprise a plurality of loading units adapted to operate as a linear array in the axial direction of the press roll, each one of the loading unit comprising a functionally cooperating piston-cylinder unit.
  • a conventional arrangement for transmitting the frictional forces from the shoe to the frame of the extended-nip press is such that on the trailing edge of the shoe is provided a plurality of support members backing the shoe and giving the shoe a support against friction forces imposed on the shoe.
  • patent publication FI 89286 is disclosed an extended-nip press having a support bearing assembly adapted to the outgoing side of the shoe for receiving the frictional forces imposed on the shoe, the support bearing assembly including at least one stationary support member connected to a support beam.
  • the disadvantages of this arrangement have arisen from the horizontal support of the shoe that may be problematic in regard to the position adjustment of the shoe by possibly restricting the degree of freedom in the range of positions adjustable for the shoe.
  • these kinds of constructions have frequently been complicated which in turn is reflected in high manufacturing and service costs of the embodiment.
  • smoothness of shoe loading has been problematic so that the shoe tends to stick at its trailing edge and service end.
  • the extended-nip press according to the invention is principally characterized by what is stated in the characterizing parts of the appended base claim.
  • the extended-nip press according to the present invention is characterized in that the piston of at least one piston-cylinder unit comprises a first end which is adapted to enter the bore of the cylinder and to tilt relative to the center axis of the cylinder.
  • the piston of said piston-cylinder unit further comprises a second end which is adapted to enter the piston mount and to tilt relative to the center axis of the piston mount.
  • the extended-nip press according to the invention is still further characterized in that the cylinder of said piston-cylinder unit is adapted movable between glide rails aligned in the axial direction of the press roll and connected so as to load the endless-loop blanket when a pressurized medium is introduced into the cylinder displacement space formed between the piston and the cylinder.
  • the above-mentioned first end of the piston is made at least partially globular.
  • Such rounding of the piston's first end allows the cylinder to tilt relative to the piston.
  • the second end of the piston is adapted into the piston mount by means of a spherical sliding bearing that allows the piston to tilt relative to the mount.
  • the first end of the piston is globular and the second end of the piston is adapted to rest in the piston mount on a spherical sliding bearing, the cylinder can move relative to the piston mount irrespective of the tilting of the piston without a change (e.g., by tilting) in the cylinder alignment.
  • the above-described piston construction is advantageous in that structural changes due to thermal expansion cannot tilt the cylinder which remains oriented upright in spite of the tilting of the piston in the cylinder bore.
  • the above-mentioned glide rails extend in a substantially contiguous fashion on both sides of the linear array of the piston-cylinder units. This arrangement provides a continuous glide surface that prevents the cylinder from moving in the machine direction, yet allowing the cylinder to move in the axial direction of the press, that is, in the cross-machine direction.
  • key elements are adapted between at least one piston-cylinder unit and at least one of the glide rails in order to prevent said at least one piston-cylinder unit from moving in the axial direction of the extended-nip press.
  • Such advantageous keyed guidance of a cylinder or plural cylinders located close to the center of the press allows thermal expansion of the shoe in either direction from the center line of the press during operation without causing problems from thermal expansion to the operation of the press.
  • the unkeyed cylinders remain free to follow the movements of the thermally expanding/contracting shoe.
  • the shoe is connected to at least one of the loading units in a fashion that allows the frictional forces imposed on the shoe to be transmitted to the loading unit.
  • the frictional forces imposed on the shoe can be transmitted to the loading unit, e.g., using such a structure wherein the cylinder end loading the shoe is made at least partially spherical.
  • the frictional force received by the cylinder from the shoe is advantageously transmitted to the roll support beam by providing at least one of the piston-cylinder units with a force-transmitting surface facing the glide rail so as to transmit the frictional forces imposed on the shoe to the roll support beam of the extended-nip press.
  • the frictional force imposed on the shoe is transmitted to the roll support beam via at least one piston-cylinder unit loading the shoe.
  • the linear array of loading units advantageously their cylinders are adapted abut each other at least partially.
  • the adjacent cylinders support each other so as to prevent the cylinders from tilting in the axial direction of press.
  • One of the greatest benefits of the extended-nip press according to the invention is its simple, yet extremely functional construction allowing the press to be fabricated at a reasonable cost, whereby both its maintenance and servicing is easy and fast. Furthermore, the extended-nip press according to the present invention is very durable in use.
  • An additional benefit of the extended-nip press according to the present invention is its capability of transmitting the frictional forces imposed on the shoe to the press frame, particularly to the roll support beam.
  • a still further benefit of the extended-nip press according to the present invention is that it is not sensitive to malfunction or incorrect loading situations that may be induced by thermal expansion of the shoe during operation.
  • FIG. 1 is a diagrammatic cross-sectional view of an extended-nip press as seen from the end of the press;
  • FIG. 2 is a diagrammatic cross-sectional view of an alternative embodiment of an extended-nip press as seen from the long side of the press, that is, a view taken in the machine direction of the press;
  • FIG. 3 is a sectional view taken along plane A-A denoted in FIG. 2.
  • FIG. 1 shows in a diagrammatic view exemplary embodiment of the construction of an extended-nip press as seen from the end of the press, that is, in a view in the cross-machine direction of the press.
  • the extended-nip press shown therein comprises an upper backing roll 1 and a lower press roll 2 that define therebetween a press zone, later called a press nip N.
  • the backing roll 1 may be a heated roll or an unheated roll.
  • the press roll 2 comprises an endless-loop blanket 3 made from a flexible and liquid-impervious material with a rigid, stationary roll support beam 4 extending axially through the interior of the endless-loop blanket.
  • the press roll 2 comprises a plurality of loading means 5 that urge the blanket 3 toward the backing roll for forming the above-mentioned nip N in order to remove water from a web W passed through the nip.
  • web refers to a paper or paperboard web.
  • the travel direction of the web passed into the nip is denoted by an arrow in the diagram.
  • the loading means 5 include a loading unit 6 which is connected to a roll support beam 4 and a shoe 8 that in turn is connected to the loading element via a saddle element 7 and is aligned parallel to the center axis of the press roll.
  • the shoe element 8 is connected to the saddle element by a key 9 inserted into both a keyway 10 made on the surface of the shoe element facing the saddle element and a keyway 11 made on the surface of the saddle element facing the shoe element.
  • the key 9 transmits the frictional forces imposed on the shoe to the saddle element.
  • the loading means 6 comprise a linear array of loading units aligned in a row in the axial direction of the press roll 2 , one of the loading units being illustrated in FIG. 1.
  • Each one of the loading units comprises a cylinder 12 and a piston 13 adapted to enter partially into the bore of the cylinder so that at least the first end 14 of the piston enters the displacement space 15 formed in the bore of the cylinder.
  • the first end 14 of the piston includes a seal element 16 serving to seal the side wall of the piston over the gap to the wall of the pressurized-medium receiving cylinder displacement space.
  • a seal element 16 serving to seal the side wall of the piston over the gap to the wall of the pressurized-medium receiving cylinder displacement space.
  • the first end of the piston is partially rounded into a globular shape at its periphery thus allowing the piston to tilt relative to the cylinder when so required.
  • the other end 18 of the piston 13 is adapted by means of a spherical sliding bearing 20 into a piston mount 19 fitted on the roll support beam 4 .
  • the spherical sliding bearing facilitates the tilting of the piston relative the piston mount.
  • the cylinder-piston combination forms a functionally cooperative piston-cylinder combination, whereby the introduction of a pressurized medium, such as hydraulic oil, via a passageway 17 of the pressurized medium into the cylinder displacement space can be-used for elevating the operating pressure of the cylinder displacement space so as to move the piston relative to the cylinder.
  • a pressurized medium such as hydraulic oil
  • the means for passing a pressurized medium to the pressurized-medium passageway as well as the means for elevating the pressure of the pressurized medium or for controlling the flow thereof are well known to a person skilled in the art, they are omitted from the diagram.
  • introduction of the pressurized medium into the cylinder displacement space will cause the cylinder to move outwardly relative to the piston so as to load the shoe.
  • each cylinder 12 on the incoming and outgoing sides of the press are adapted glide rails 21 serving to support the cylinder in the machine direction of the press.
  • the glide rails are connected by screws to the roll support beam 4 . Being thus supported to the glide rails, the cylinder cannot tilt in the machine direction when the cylinder is being actuated by the pressurized medium introduced into the cylinder displacement space.
  • the surface of the cylinder remaining on the outgoing side of the press is provided with a force-receiving surface 22 adapted to rest against the glide rail so as to transmit the frictional forces imposed on the shoe via the glide rail to the roll support beam.
  • An additional feature of the cylinder is that its top surface is substantially spherical as drawn in the diagram.
  • the saddle element 7 is a planar component with its underside, that is, the surface facing the loading element, machined to incorporate a concave recess that after the saddle element is connected to the loading unit allows the spherical end surface of the loading unit and this concave recess of the saddle element to form a ball joint allowing the shoe element connected to the saddle element to rotate relative to the loading unit. Also the frictional forces imposed on the shoe are transmitted via this spherical end surface of the loading unit from the saddle element to the loading unit.
  • the shoe element 8 shown in FIG. 1 is made from a suitable metal such as aluminum.
  • the top surface of the shoe element opposed to the backing roll has a concave cross section.
  • the concave top surface may also be contoured to include a hydrodynamic pressure pocket.
  • the pressure pocket may be designed to perform as a hydrostatic pressure pocket, whereby the shoe would additionally comprise at least one line connection for feeding cooling/lubricating oil into the pressure pocket.
  • the endless-loop blanket assumes a shape that is determined by the concave face of the shoe and by the curvature of the backing roll adapted to cooperate with the press roll, whereby the blanket together with the backing roll defines a press zone through which the paper or paperboard web can be passed to remove water from the web.
  • an extended-nip press includes other parts and elements omitted from the diagrams for greater clarity. These means are, e.g., means for feeding coolant and lubricant onto the top surface of the shoe, means for feeding pressurized medium into the cylinder acting as the loading element, etc. Furthermore, an extended-nip press may be implemented in an inverted fashion, whereby the press roll is located above the backing roll.
  • FIG. 2 shows diagrammatically a partially cross-sectional view of an extended-nip press as seen from the long side of the press.
  • FIG. 3 is shown a sectional view taken along plane A-A denoted in FIG. 2.
  • the reference numerals used in FIGS. 2 and 3 are principally the same as those of FIG. 1.
  • the contiguous shoe 8 is loaded by nine loading units 6 to press the endless-loop blanket 3 against backing roll 1 .
  • the number of loading units in an extended-nip press may be varied so as to be a larger or a smaller number than used in the exemplifying embodiment. In practice, the number of loading units required is dictated by the width of the press and the desired control precision of the cross-machine nip pressure profile.
  • the cylinders placed in the row are arranged to partially abut each other. Due to this arrangement, the adjacent cylinders support each other so as to prevent the cylinders from tilting in the axial direction of the extended-nip press.
  • At least one of the glide rails may be contoured to have a recess at the location of the loading unit to be clamped.

Landscapes

  • Paper (AREA)
  • Press Drives And Press Lines (AREA)
  • Rolls And Other Rotary Bodies (AREA)
US10/186,421 2001-07-05 2002-07-02 Extended-nip press Abandoned US20030015306A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20011471 2001-07-05
FI20011471A FI116227B (sv) 2001-07-05 2001-07-05 Långnypspress

Publications (1)

Publication Number Publication Date
US20030015306A1 true US20030015306A1 (en) 2003-01-23

Family

ID=8561596

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/186,421 Abandoned US20030015306A1 (en) 2001-07-05 2002-07-02 Extended-nip press

Country Status (4)

Country Link
US (1) US20030015306A1 (sv)
EP (1) EP1273700A1 (sv)
CN (1) CN1396337A (sv)
FI (1) FI116227B (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050274476A1 (en) * 2004-06-11 2005-12-15 Roland Bengtsson Shoe press

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE526787C2 (sv) * 2003-10-21 2005-11-01 Metso Paper Karlstad Ab Elastiskt derformerbar stödkropp för en anordning med förlängt nyp för behandling av fiberbana och användning av sådan stödkropp
FI118088B (sv) * 2004-02-19 2007-06-29 Vaahto Oy Anordning för belastning av en skopress
FI126727B (sv) * 2012-10-19 2017-04-28 Valmet Technologies Inc Skovals, långnypspress och fiberbanmaskin

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4423212C1 (de) * 1994-07-01 1996-03-07 Escher Wyss Gmbh Walzenanordnung
CA2259768C (en) * 1998-01-30 2004-05-11 Valmet Corporation Shoe press
EP1198639B1 (en) * 1999-05-06 2004-10-13 Metso Paper, Inc. Shoe press

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050274476A1 (en) * 2004-06-11 2005-12-15 Roland Bengtsson Shoe press
US7387710B2 (en) * 2004-06-11 2008-06-17 Metso Paper, Inc. Shoe press

Also Published As

Publication number Publication date
FI20011471A0 (sv) 2001-07-05
FI116227B (sv) 2005-10-14
FI20011471A (sv) 2003-01-06
EP1273700A1 (en) 2003-01-08
CN1396337A (zh) 2003-02-12

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Legal Events

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AS Assignment

Owner name: VAAHTO OY, FINLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:AHO, ERKKI;LAARI, AKI;REEL/FRAME:013346/0634

Effective date: 20020708

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION