EP0055206B1 - Pressenteil zum im wesentlichen gleichmässigen Pressen der beiden Seiten einer Papierbahn - Google Patents

Pressenteil zum im wesentlichen gleichmässigen Pressen der beiden Seiten einer Papierbahn Download PDF

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Publication number
EP0055206B1
EP0055206B1 EP81630083A EP81630083A EP0055206B1 EP 0055206 B1 EP0055206 B1 EP 0055206B1 EP 81630083 A EP81630083 A EP 81630083A EP 81630083 A EP81630083 A EP 81630083A EP 0055206 B1 EP0055206 B1 EP 0055206B1
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EP
European Patent Office
Prior art keywords
nip
web
roll
press
dewatering
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.)
Expired
Application number
EP81630083A
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English (en)
French (fr)
Other versions
EP0055206A1 (de
Inventor
Donald Alexander Ely
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.)
Beloit Corp
Original Assignee
Beloit Corp
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 Beloit Corp filed Critical Beloit Corp
Publication of EP0055206A1 publication Critical patent/EP0055206A1/de
Application granted granted Critical
Publication of EP0055206B1 publication Critical patent/EP0055206B1/de
Expired 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
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/48—Suction apparatus
    • 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
    • D21F3/04—Arrangements thereof

Definitions

  • This invention relates to a papermaking machine dewatering press section for substantially equally pressing and dewatering both faces of a freshly felted paper web, comprising:
  • a dewatering press section for a papermaking machine of this type is known from US-A-4 188 262.
  • US-A-4 188 262 Although the art of pressing and dewatering a paper web is already rather highly developed, as exemplified by US-A-4 188 262, there is still substantial room for improvement.
  • the Fig. 1 embodiment of US-A-4 188 262 has disadvantages as regards equal pressing and felting of the opposite faces of the web, the web being dewatered after passage through a double felted nip, in the two successive nips through the same face and being thereafter compacted.
  • the Fig. 2 embodiment of US-A-4 188 262 is more advantageous as regards equal pressing and felting of the opposite web faces but has other essential drawbacks.
  • a four roll stack defining three press nips is followed by a further pair of rolls defining an additional press nip.
  • one of the felts passes through successive nips on the same roll and the web must be transferred after the first nip from one felt to another. This may cause damaging of the web after passage through the first nip.
  • the bottom side of the web is exposed to only one felted nip before the fourth nip. This is disadvantageous because it does not provide for appropriate compacting of the bottom side of a web which has different characteristics when formed in a single wire machine.
  • the web is unsupported by a felt or roll between the third and fourth nip. This "open draw" is a further disadvantage because it may cause web flutter and, ultimately, a break in the web.
  • the object of the present invention is to overcome the disadvantages, drawbacks, inefficiencies, shortcomings and problems inherent in prior press sections and their operation, and to provide a new and improved press section which will attain substantially equal ink, size or coating receptivity or absorption, i.e. compaction, on both faces of a paper sheet resulting from a freshly felted paper sheet web, in a simplified manner, in compact space, free from open draws in the press section, conserves operating energy, and provides for equal pressing and felting of both faces of the web.
  • the papermaking machine dewatering press section is characterized in that the double felted first nip is provided by press rolls arranged in the direction of web movement forwardly of said four roll stack, and the first nip in said stack is the single felted second nip which is formed between a grooved roll and a porous covered roll, the second nip in said stack is the unfelted third nip which is formed between the porous covered roll and a smooth hard surface roll and the third nip in said stack is the single felted fourth nip which is formed between the smooth hard surface roll and a further grooved roll.
  • Opposite faces of the web are equally dewatered and compacted in a compact space machine free from open draws.
  • the double felted press nip forwardly of the four roll stack and providing the four roll stack with a first single felted nip, the bottom face or wire face of the web may be dewatered in two successive nips. None of the felts passes through two successive nips on a single roll of the four roll stack. It is accordingly not necessary to transfer in the four roll stack the web from one felt to another, thus reducing the risk of damaging the web.
  • the porous covered roll takes over the web after passage through the first nip in the four roll stack and releases the web to the smooth hard surface roll after passing through the unfelted nip formed therebetween.
  • a paper making machine dewatering press section 5 includes a pickoff device 8 adapted to be located adjacent downstream from paper web forming means and operating to lift a freshly formed, i.e. felted, paper sheet web W from a forming belt, wire or fabric 8 for further processing in the press section.
  • the pickoff device 7 comprises a pickoff roll 9 equipped with a suction gland 10 and running in engagement with the upper face of an endless belt dewatering felt 11 which is pressed against the web W on the forming fabric 8 at the nip of the roll 9 with the fabric. Suction from the gland 10 causes the web W to separate from the generally upwardly facing forming fabric 8 and adhere to the generally downwardly facing surface of the dewatering felt 11 which carries the web onward to a first press roll means 12.
  • the dewatering felt 11 runs together with an endless upwardly facing second porous dewatering felt with the web W engaged therebetween through a first pressing and dewatering nip N-1 provided by and between a suction roll 14 and a grooved roll 15.
  • the suction roll 14 is on the lower side of the nip N-1 and the grooved roll 15 on the upper side of the nip N-1, so that although in the nip itself substantially equal dewatering results through both faces of the web W, the suction provided by a suction device 17 in the roll 14 effects separation of the web W from the upper felt 11 so that the web W can travel onwardly in machine direction carried on top of the lower felt 13.
  • the upper press roll 15 may embody a structure substantially according to U.S. Patent 3 198 697, that is the perimeter of the roll is provided with a set of axially spaced annular grooves 18.
  • second press roll means 19 comprising a four roll stack providing a second nip N-2, a third nip N-3 and a fourth nip N-4, through which the web runs successively.
  • the nip N-2 is provided by an upper porous covered press roll 20 and a lower grooved roll 21.
  • the dewatering felt 13 engages the grooved roll 21 and the lower face of the web W
  • the porous covered roll 20 engages the other or upper face of the web.
  • the grooved roll 21 is similar to the grooved roll 15, having an axially spaced set of circumferential annular grooves 22 (Fig. 2).
  • the grooves 22 avoid any tendency towards vacuum retention of the web W on the felt 13, so that the web easily releases from the web 13 at the exit from the nip N-2 for travel on the perimeter of the roll 20 to the nip N-3.
  • the press roll 20 has a porous elastomer cover 23.
  • the cover 23 may be about 1" thick and formed from a suitable elastomer in a 5 to 30 P & J hardness range, which enables the pressing perimeter of the roll 20 to yield slightly under web pressing nipping pressure to minimize crushing the paper web fibers.
  • the degree of hardness of the cover 23 can at least to some extent be determined by the degree of porosity of the cover, that is the size and number of porosity voids 24 in the material of the cover. As noted in Fig.
  • some of the pores 24 open outwardly at the nipping perimeter of the roll 20 and facilitate operation of the roll 20 by capturing water pressed from the web W and thus facilitating release of the web from the roll 20 after the web passes through the nip N-3.
  • a doctor 25 acts on the free offrunning perimeter of the roll 22 beyond the nip N-3.
  • a felt wick 27 may engage the perimeter of the roll 20 either before or after the doctor 25, but preferably after, for applying a web release agent supplied from supply means 28 with which the wick communicates.
  • a suitable spray device may be used, if preferred. It will be appreciated, of course, that the pressing perimeter porosity of the cover 23 should be of a character to avoid marring the surface of the web W in contact with the roll at the nips N2 and N3.
  • the web W which has travelled from the nip N-2 on the perimeter of the roll 20, is pressed between the perimeter of the roll 20 and the nipping perimeter of a hard surfaced roll 29.
  • the roll 29 may have a plastic cover, it should be of bone hardness and which according to paper machine standards is equivalent to about 0 P & J hardness. Since the nipping perimeter of the roll 29 is smooth, the softer porous perimeter of the roll 20 will easily release the web W from the perimeter of the roll 20 to follow the perimeter of the roll 29 on the offrunning side of the nip N-3. Such release may, of course, be further facilitated by treating the surface of the roll 20 with a release agent, as by means of the wick 27.
  • the roll 29 may be driven rotatably by suitable drive means 30 and cause driving of the other rolls in the stack in the press means 19.
  • the web W is engaged on its lower face directly by the perimeter of the roll 29, and on its upper face by a third endless belt dewatering felt 31 which runs through the nip N-4 with the web W and in engagement with the perimeter of a grooved press roll 32 of substantially the same type as the press rolls 15 and 21, and having a set of axially spaced annular peripheral grooves 32 (Figs. 1 and 4).
  • a third endless belt dewatering felt 31 which runs through the nip N-4 with the web W and in engagement with the perimeter of a grooved press roll 32 of substantially the same type as the press rolls 15 and 21, and having a set of axially spaced annular peripheral grooves 32 (Figs. 1 and 4).
  • the web now substantially dewatered and densified leaves the roll 29 and the felt 31 and travels on, as for example, past a guide roller 34 as a sheet W/S which is possessed of substantially equal ink, size or coating receptivity or absorption characteristics.
  • a doctor blade 35 on the perimeter of the roll 29 adjacent to the offrunning side of the nip N-4 will effect separation of the advancing leading end, which can then be directed about the guide roller 34 and onward to a calender, winder, or the like.
  • the doctor 35 is adapted to maintain the perimeter of the roll substantially dean.
  • the substantially equal surface characteristics of the paper sheet W/S leaving the press section 5 results from the substantially equal dewatering and pressing treatment applied to each of the web faces in progressing through the press section.
  • dewatering is effected through both of the web faces, that is, water is caused to leave through both of the faces and thus fines in the web migrate substantially equally from the core of the web toward each face.
  • nip N-2 dewatering is effected through the lower face of the web W as indicated by the directional arrow in Fig. 2, while the upper face is compacted by the perimeter of the roll 20.
  • the web W On traveling through the nip N-3, the web W is substantially equally compacted by the direct nipping engagement of the rolls 20 and 29 with the opposite faces, as exemplified in Fig. 3 by the double headed arrow.
  • each face of the web has substantially equal concentration of fines so that the desirable equal receptivity or absorption characteristics are attained.

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  • Paper (AREA)

Claims (6)

1. Enwässerungspreßabschnitt für eine Papierherstellungsmaschine zum im wesentlichen gleichen Pressen und Entwässern beider Seiten einer frisch gefilzten Papierbahn, mit:
mehreren porösen Entwässerungsfilzen (11, 13, 31), mehreren Preßwalzen (14, 15, 20, 21, 29, 32), die aufgrund ihrer Anordnung bilden:
einen doppelt befilzten ersten Entwässerungspreßspalt (N-1), durch den die Bahn (W) in Berührung zwischen zwei der porösen Entwässerungsfilze (11, 13) hindurchgeht, so daß die Bahn (W) über ihre beiden Seiten in dem Spalt (N-1) entwässert wird,
eine einfach befilzten zweiten Entwässerungsspalt (N-2), durch den die Bahn (W) hindurchgeht, wobei eine ihrer Seiten mit einem (13) der porösen Entwässerungsfilze (11, 13, 31) in Berührung ist und ihre entgegengesetzte Seite in direkter verdichtender Berührung mit einer (20) der Preßwalzen (14, 15, 20, 21, 29, 32) ist,
wobei die Bahn (W) über eine ihrer Seiten in dem zweiten Spalt (N-2) entwässert wird,
einen umbefilzten dritten Preßspalt (N-3), durch den die Bahn (W) hindurchgeht, wobei beide Seiten in direkter Berührung mit zwei (20, 29) der Preßwalzen (14, 15, 20, 21, 29, 32) sind,
einen einfach befilzten vierten Entwässerungsspalt (N-4), durch den die Bahn (W) hindurchgeht, wobei ihre entgegengesetzte Seite mit einem (31) der porösen Entwässerungsfilze (11, 13, 31) in Berührung ist und ihre eine Seite in direkter verdichtender Berührung mit einer (29) der Preßwalzen (14, 15, 20, 21, 29, 32) ist, wobei die Bahn (W) über die entgegengesetzte Seite in dem vierten Spalt (N-4) entwässert wird,
wobei drei der Preßspalte (N-1 bis N-4) durch ein Vierwalzenwerk (19) gebildet sind und einer der Spalte zwischen Preßwalzen gebildet ist, die von dem Vierwalzenwerk (19) getrennt sind,
dadurch gekennzeichnet, daß der doppelt befilzte erste Spalt (N-1) durch Preßwalzen (14, 15) gebildet ist, die in der Richtung der Bahnbewegung vorderhalb des Vierwalzenwerks (19) angeordnet sind, daß der erste Spalt in dem Vierwalzenwerk der einfach befilzte zweite Spalt (N-2) ist, der zwischen einer Rillenwalze (21) und einer porösen umhüllten Walze (20) gebildet ist, daß der zweite Spalt in dem Vierwalzenwerk der unbefilzte dritte Spalt (N-3) ist, der zwischen der porösen umhüllten Walze (20) und einer an der Oberfläche glatten und harten Walze (29) gebildet ist, und daß der dritte Spalt in dem Vierwalzenwerk der einfach befilzte vierte Spalt (N-4) ist, der zwischen der an der Oberfläche glatten und harten Walze (29) und einer weiteren Rillenwalze (32) gebildet ist.
2. Preßabschnitt nach Anspruch 1, dadurch gekennzeichnet, daß der doppelt befilzte erste Preßspalt (N-1) zwischen zwei Preßwalzen (14, 15) gebildet ist, die eine Saugwalze (14) und eine Rillenwalze (15), welche gegeneinander gepreßt sind, aufweisen.
3. Preßabschnitt nach Anspruch 1 oder 2, wobei eine Abnehmvorrichtung (7) stromabwärts neben der Papierbahnbildungseinrichtung angeordnet ist und eine Saugwalze (9) zum Abnehmen der frisch gebildeten Papierbahn (W) von einem Seibband (8) aufweist, dadurch gekennzeichnet, daß die Abnehmsaugwalze (9) in der Schleife angeordnet ist, welche durch einen ersten (11) der Filze (11, 13, 31) gebildet ist, und zum Übergeben der Bahn (W) von dem Siebband (8) auf einen nach unten weisenden Teil des ersten Filzes (11) dient, der mit der Bahn durch den ersten Spalt (N-1) hindurchgeht, wobei ein zweiter (13) der Filze (11, 13, 31) ebenfalls durch den ersten Spalt (N-1) hindurchgeht und die Bahn auf seiner Oberseite durch den zweiten Spalt (N-2) transportiert, wobei der erste Filz (11) nach dem ersten Spalt (N-1) von der Bahn (W) getrennt wird und wobei der zweite Filz (13) nach dem zweiten Spalt (N-2) von der Bahn (W) getrennt wird.
4. Preßabschnitt nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß Einrichtungen (28, 27) vorgesehen sind zum Behandeln der Oberfläche der porösen umhüllten Walze (20) mit einem Trennmittel.
5. Preßabschnitt nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die an der Oberfläche glatte und harte Walze (29) eine angetriebene Walze des Vierwalzenwerks ist.
6. Preßabschnitt nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die poröse umhüllte Walze (20) an ihrem Umfang offene Poren hat.
EP81630083A 1980-12-18 1981-12-18 Pressenteil zum im wesentlichen gleichmässigen Pressen der beiden Seiten einer Papierbahn Expired EP0055206B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US217657 1980-12-08
US21765780A 1980-12-18 1980-12-18

Publications (2)

Publication Number Publication Date
EP0055206A1 EP0055206A1 (de) 1982-06-30
EP0055206B1 true EP0055206B1 (de) 1985-08-07

Family

ID=22811969

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81630083A Expired EP0055206B1 (de) 1980-12-18 1981-12-18 Pressenteil zum im wesentlichen gleichmässigen Pressen der beiden Seiten einer Papierbahn

Country Status (8)

Country Link
EP (1) EP0055206B1 (de)
JP (1) JPS5922838B2 (de)
KR (1) KR850001609B1 (de)
BR (1) BR8108279A (de)
DE (1) DE3171746D1 (de)
ES (1) ES8302824A1 (de)
FI (1) FI79731C (de)
IN (1) IN154483B (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI71370C (fi) * 1983-05-06 1986-12-19 Valmet Oy Slutet pressparti i pappersmaskin
FI72362C (fi) * 1983-10-03 1987-05-11 Tamfelt Oy Ab Foerfarande och medel foer att aostadkomma avlaegsnande av vatten i en press vid en pappersmaskin.
ES2105720T3 (es) * 1993-05-29 1997-10-16 Voith Gmbh J M Prensa para una maquina papelera para papeles finos.

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE273783C (de) *
GB697774A (en) * 1950-11-16 1953-09-30 Ralph Chalinor Heys Improvements in or relating to paper-making machines
US3198693A (en) * 1964-08-21 1965-08-03 Beloit Corp Scavenging means for grooved press rolls
US3268390A (en) * 1965-10-28 1966-08-23 Beloit Corp Grooved roll double-felted press for papermaking
US4188262A (en) * 1972-11-30 1980-02-12 Valmet Method for dewatering paper in a paper machine press section
GB1381360A (en) * 1972-12-12 1975-01-22 Valmet Oy Paper machine multi-roll press assemblies
FR2343858A1 (fr) * 1976-03-12 1977-10-07 Neyrpic Bmb Perfectionnement aux sections presses des machines a papier et voiles de fibres

Also Published As

Publication number Publication date
KR850001609B1 (ko) 1985-10-24
ES508018A0 (es) 1983-02-01
FI79731C (fi) 1990-02-12
DE3171746D1 (en) 1985-09-12
EP0055206A1 (de) 1982-06-30
FI79731B (fi) 1989-10-31
BR8108279A (pt) 1982-10-05
JPS57121695A (en) 1982-07-29
ES8302824A1 (es) 1983-02-01
JPS5922838B2 (ja) 1984-05-29
IN154483B (de) 1984-11-03
FI813825L (fi) 1982-06-19
KR830007957A (ko) 1983-11-09

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