EP0405154A1 - Formiervorrichtung für Papiermaschine - Google Patents

Formiervorrichtung für Papiermaschine Download PDF

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Publication number
EP0405154A1
EP0405154A1 EP90110145A EP90110145A EP0405154A1 EP 0405154 A1 EP0405154 A1 EP 0405154A1 EP 90110145 A EP90110145 A EP 90110145A EP 90110145 A EP90110145 A EP 90110145A EP 0405154 A1 EP0405154 A1 EP 0405154A1
Authority
EP
European Patent Office
Prior art keywords
moist paper
paper
roll
dewatering
wire
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.)
Withdrawn
Application number
EP90110145A
Other languages
English (en)
French (fr)
Inventor
Akihito C/O Mihara Machinery Works Nagano
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.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Heavy Industries Ltd
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 Mitsubishi Heavy Industries Ltd filed Critical Mitsubishi Heavy Industries Ltd
Publication of EP0405154A1 publication Critical patent/EP0405154A1/de
Withdrawn legal-status Critical Current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
    • 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
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/02—Complete machines for making continuous webs of paper of the Fourdrinier type

Definitions

  • the present invention relates to a moist paper forming device applied to a paper machine.
  • FIG. 4 there is illustrated a typical example of a prior art twin wire device includ­ing an upper wire unit.
  • a stock 2 ejected from a head box 1 is settled down on a lower wire 3 assuming a looped configuration and dewatered downwards by means of an initial dehydrator 4 disposed under the lower wire 3, whereby the stock 2 is changed into a sheet of moist paper 2a. Thereafter, the moist paper 2a is dewatered both upwards and downwards by means of an upper and lower dehydrators 5 and 6 while being sandwiched in between the lower wire 3 and an upper looped wire 9 which constitutes a throat part for holding the stock 2 in combination with introduction rolls 16.
  • the upper wire 9 separates from the moist paper formed on the lower wire 3, while the moist paper is further dewatered downwards by means of a water content adjuster 7 provided downwardly of the lower wire 3.
  • the moist paper is separated from the lower wire by a suction pick-up roll 8 and shifted to a press part subsequent thereto.
  • FIG. 5 there is given one example of the prior art upper and lower hydrators 5 and 6 shown in FIG. 4.
  • the stock 2 depicted in FIG. 4 is dehydrated downwards by low vacuum boxes 22 and lead-in shoes 27 of an initial dehydrating unit 4 and adjusted to exhibit a mat concentration of approximately 1.5%, thereby changing the stock into the moist paper 2a.
  • the moist paper 2a is sandwiched in between the upper and lower wires 9 and 3 at an inlet part of a lower shoe box 10 depicted in FIG. 5 and undergoes pulse dewatering pressures from a plurality of shoe blades 21 and a lead-in shoe 17 of the lower shoe box 10, whereby the moist paper 2a is dewatered to form a paper layer.
  • the dehydration water accumulated in an upper part of the shoe box 10 is led in an auto-slice 18.
  • the upper wire 9, the stock and the lower wire 3 are wound at a curvature opposite to a curvature of the shoe box 10 with the aid of a central roll 12 located in rear of the auto-slice 18.
  • the stock is subjected to a surface pressure and centrifugal force, thus dewatering the stock downwards.
  • the upward water sucked out of the stock at a separation unit of the central roll 12 and the upper wire 9 is received by a save-all 23.
  • the stock is de­watered between a Fourdrinier part and the upper and lower wires, and a moist paper web formed with a paper layer is carried to the lower wire by use of a sheet transfer box 14 of the upper and lower wire separation unit.
  • a rate of the upward dehydration drops down with a rise in the sheet making velocity.
  • Typical paper properties such as a paper formation, a difference between frontside and backside of a paper and a paper thicknesswise strength strongly correlates to the rate of upward dehydration. In order to satisfy those properties, it is required that a proper rate of upward dehydration be held. Hence, as in the prior art moist paper forming device, it is undesirable that the rate of upward dehydration has a dependency on the velocity.
  • a conceivable method is that a vacuum dewatering box 24 is, as illustrated in FIG. 6, provided within a wire loop shaped by the lower wire 3 in front of the central roll 12. This arrangement, however, presents a problem of causing an increment in the rate of downward dehydration.
  • a vacuum dewatering box 32 formed with a plurality of slots 31 in place of the central roll 12.
  • This arrangement needs the formation of slots the number of which corresponds to a dewatering capability of the central roll, and hence a vacuum dewatering section becomes considerably long.
  • the water is sucked just in the upper direction, and a vacuum value is required to increase.
  • the vacuum dehydrator 32 as an upper dewatering device.
  • a life-span of the upper wire 9 is diminished.
  • a phenomenon concomitant with the placement for effecting dehydration just in the upper direction is that the slots are jammed with fibers when the mat concentra­tion gradually increases. This problem is serious.
  • a moist paper forming device for a paper machine, comprising: a lower wire, continu­ously formed in a looped configuration and having its upper part onto which a stock is continuously fed, for carrying the stock while dewatering the stock downwards; an upper wire relatively provided on the way of the lower wire; an introduction roll disposed to constitute a throat part for seizing a sheet of thus formed moist paper between the upper and lower wires; a shoe box incorporating a plurality of upwardly convex and curvilinearly arranged shoe blades, starting from the throat part in a loop shap­ed by the lower wire, for dewatering the moist paper so that the upper and lower wires and the moist paper travel while being wound thereon; and an auto-slice for scraping the water emerging when the moist paper undergoes upward dehydration by the shoe blades, characterized by further comprising: a dewatering roll disposed on a rear stream side of the shoe box and wound with
  • the upper and lower wires and the moist paper which have been deflected by the central roll move in a substantially horizontal direc­tion or in an upper direction.
  • the vacuum dewatering unit for moving the moist paper to the lower wire involves the use of a suction couch roll.
  • the pressure generated becomes greater according as a filtration resistance is larger with respect to the roll diameter and the wire tension.
  • a filtration pheno­menon is dominant, wherein the mats are formed sequentially from a part more vicinal to the forming wire and have higher density on undergoing compressive forces. More specifically, the mats formed earlier have greater filtra­tion resistances.
  • the underside mats of the moist paper formed as a result of effecting the downward dehydration by the lower wire are denser than those disposed thereabove and exhibit larger filtration resistances.
  • the upward dehydration is carried out, i.e., toward the upper mats having smaller filtration resistances by use of the shoe box disposed within the lower loop and incorporating a plurality of upwardly convex and curvilinearly arranged shoe blades in cooperation with the dewatering roll wound with upper and lower wires and the moist paper at a curvature prescribed in the same direction as that of a curvature of the shoe blades.
  • a good deal of dehydration quantity can be obtained with less dewatering pressures. Therefore, the mat concentra­tion well increases at that time. In consequence, the mat concentration when entering the central roll remains sufficiently high even when the sheet making velocity increases, thereby making it possible to prevent the "crushing" phenomenon from being developed at the central roll.
  • FIG. 1 A first embodiment of the present invention will hereinafter be described with reference to FIG. 1.
  • FIG. 1 the same components as those of prior art moist paper forming devices depicted in FIGS. 4 and 5 are marked with the like symbols, and the description is therefore omitted herein.
  • a lower shoe box 10 incorporating a plurality of shoe blades 21 and a lead-in shoe 17.
  • the plurality of shoe blades 21 are upwardly convex and curvilinearly arranged.
  • An auto-slice 18 is so provided in a loop shaped by the upper wire 9 as to face the lower shoe box 10.
  • a de­watering roll 50 Disposed within the loop shaped by the lower wire 3 on a downstream side of the shoe box 10 is a de­watering roll 50 would with the upper and lower wires 9 and 3 and a sheet of moist paper 2a at a curvature pre­scribed in the same direction as that of a curvature of the shoe blades 21.
  • a save-all 51 and a vacuum dehydrator 52 are located vis-a-vis with the dewatering roll 50.
  • a central roll 12 Disposed on the downstream side of the dewatering roll 50 is a central roll 12 wound with the upper and lower wires 9 and 3 and the moist paper 2a at a curvature prescribed in an oppo­site direction to that of the dewatering roll 50.
  • a water content adjuster 7 and a suction couch roll 60 are provided in the loop shaped by the lower wire 3 in the section of that hori­zontal movement.
  • the numeral 8 represents a suction pick-up roll, and 15 designates a roll for sepa­rating the upper roll 9.
  • the moist paper 2a dewatered downwards by the lower wire 3 is sandwiched in between the upper and lower wires 9 and 3 on the lead-in shoe 17 and dewatered upwards with wire tensions.
  • the moist paper 2a is further dewatered mainly upwards by the upwardly convex and curvilinearly arranged shoe blades 21 of the shoe box 10.
  • the dewatered water is collected by the auto-slice 18 and discharged outside the system.
  • the moist paper 2a is dewatered upwards by means of the dewatering roll 50 wound with the upper and lower wires 9 and 3 and the moist paper 2a at a cur­vature prescribed in the same direction as that of the curvature of the shoe blades 21.
  • the scattered water enters the save-all 51 and is led to the outside of the system.
  • the hydration is effected by a vacuum dehydrator 52, and a vacuum value thereof is controlled to obtain an optimum upward de­watering ratio while observing the paper quality.
  • a vacuum dehydrator 52 In order to prevent clogging in the slots of the vacuum dehydrator 52, as illustrated in the Figure, an embracing angle of the dewatering roll 50 is set large, and a spac­ing from the central roll 12 is secured, and a discharge port of the vacuum dehydrator 52 is located lower than the slots. With this arrangement, the clogging can be prevented. Note that an amount of dehydration by the vacuum dehydrator 50 is small, and a vacuum width equiva­lent to approximately 3 slots at the maximum suffices.
  • the upper and lower webs and the moist paper 2a are wound on the central roll 12 at a curvature prescribed in an opposite direction to that of the dewatering roll 50, while the moist paper 2a is subjected to the downward dewatering action of the central roll 12.
  • the mat concentration of the moist paper wound on the central roll is to increase because of having performed the upward dehydration of the moist paper 2a up to the central roll 12, thereby steering clear of the "crushing" phenomenon at the central roll 12.
  • the moist paper web 2a is deflected upwardly in a horizontal direc­tion where the downward dehydration is carried out by the central roll 12 and further dewatered by the water content adjuster 7.
  • the moist paper web 2a is transferred to the lower wire on the suction couch roll 60 and further to the next press part after being separated from the lower wire by the suction pick-up roll 8.
  • the moist paper 2a is dewatered upwards by the dewatering roll 50 as well as by the shoe box 10 and then dewatered downwards by the central roll 12. Since the mat concentration of the moist paper 2a has already increased, the occurrence of the "crushing" phenomenon at the central roll 12 can be prevented.
  • the transfer of the moist paper 2a to the lower wire 3 is made at the final stage of dehydration by the moist paper forming device, and hence the moist paper has a high concentration. Almost no adhesion of fibers to the upper wire 9 can be seen, resulting in a remarkably small amount of contamination on the upper wire 9. In addition, a frequency at which the paper is cut off can be reduced.
  • FIG. 2 A descriptive emphasis will next be placed on a second embodiment of the present invention with reference to FIG. 2.
  • the components employed and the dewatering functions in the second embodiment are much the same as those in the first embodiment.
  • a characteristic arrange­ment is that the deflection at the central roll 12 is set large; and the upper wire 9, the lower wire 3 and the moist paper 2a are moved upwardly by a sheet transfer box 14 disposed on the downstream side of the central roll 12 for returning the level to a height of the existing wire.
  • a sheet transfer box 14 disposed on the downstream side of the central roll 12 for returning the level to a height of the existing wire.
  • the present invention exhibits the following effects.

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  • Paper (AREA)
EP90110145A 1989-06-06 1990-05-29 Formiervorrichtung für Papiermaschine Withdrawn EP0405154A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP142204/89 1989-06-06
JP1142204A JPH038889A (ja) 1989-06-06 1989-06-06 抄紙機の湿紙形成装置

Publications (1)

Publication Number Publication Date
EP0405154A1 true EP0405154A1 (de) 1991-01-02

Family

ID=15309811

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90110145A Withdrawn EP0405154A1 (de) 1989-06-06 1990-05-29 Formiervorrichtung für Papiermaschine

Country Status (4)

Country Link
EP (1) EP0405154A1 (de)
JP (1) JPH038889A (de)
KR (1) KR930003327B1 (de)
FI (1) FI902791A0 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4141607A1 (de) * 1991-12-17 1993-06-24 Voith Gmbh J M Doppelsiebformer
EP0576798A1 (de) * 1992-06-12 1994-01-05 Voith Sulzer Papiermaschinen GmbH Doppelsiebformer
WO1997042374A1 (en) * 1996-05-06 1997-11-13 Beloit Technologies, Inc. Pulp and linerboard former with improved dewatering
DE10116364A1 (de) * 2001-04-02 2002-10-10 Voith Paper Patent Gmbh Saugelement

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102236703B1 (ko) * 2020-07-17 2021-04-06 주식회사 아진피앤피 제지생산설비 초지공정의 지필형성부 구조체

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3138133A1 (de) * 1981-09-04 1983-03-24 Escher Wyss Gmbh, 7980 Ravensburg Entwaesserungseinheit fuer langsieb-papiermaschinen
DE3447509A1 (de) * 1983-12-30 1985-08-01 Mitsubishi Jukogyo K.K., Tokio/Tokyo Doppelsiebformpartie einer papiermaschine
AT382655B (de) * 1981-10-29 1987-03-25 Escher Wyss Gmbh Papiermaschine mit zwei beweglichen wasserdurchlaessigen entwaesserungsbaendern, z.b. sieben

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3138133A1 (de) * 1981-09-04 1983-03-24 Escher Wyss Gmbh, 7980 Ravensburg Entwaesserungseinheit fuer langsieb-papiermaschinen
AT382655B (de) * 1981-10-29 1987-03-25 Escher Wyss Gmbh Papiermaschine mit zwei beweglichen wasserdurchlaessigen entwaesserungsbaendern, z.b. sieben
DE3447509A1 (de) * 1983-12-30 1985-08-01 Mitsubishi Jukogyo K.K., Tokio/Tokyo Doppelsiebformpartie einer papiermaschine

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4141607A1 (de) * 1991-12-17 1993-06-24 Voith Gmbh J M Doppelsiebformer
US5507918A (en) * 1991-12-17 1996-04-16 J.M. Voith Gmbh Twin-wire former
EP0576798A1 (de) * 1992-06-12 1994-01-05 Voith Sulzer Papiermaschinen GmbH Doppelsiebformer
WO1997042374A1 (en) * 1996-05-06 1997-11-13 Beloit Technologies, Inc. Pulp and linerboard former with improved dewatering
US5783045A (en) * 1996-05-06 1998-07-21 Beloit Technologies, Inc. Pulp and linerboard former with improved dewatering
DE10116364A1 (de) * 2001-04-02 2002-10-10 Voith Paper Patent Gmbh Saugelement

Also Published As

Publication number Publication date
KR910001167A (ko) 1991-01-30
FI902791A0 (fi) 1990-06-05
JPH038889A (ja) 1991-01-16
KR930003327B1 (ko) 1993-04-26

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