EP0369296A2 - Doppelsieb-Papiermaschine - Google Patents

Doppelsieb-Papiermaschine Download PDF

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Publication number
EP0369296A2
EP0369296A2 EP89120612A EP89120612A EP0369296A2 EP 0369296 A2 EP0369296 A2 EP 0369296A2 EP 89120612 A EP89120612 A EP 89120612A EP 89120612 A EP89120612 A EP 89120612A EP 0369296 A2 EP0369296 A2 EP 0369296A2
Authority
EP
European Patent Office
Prior art keywords
wire
dewatering
shoe
loop
paper machine
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Withdrawn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
EP89120612A
Other languages
English (en)
French (fr)
Other versions
EP0369296A3 (de
Inventor
Akihito C/O Mihara Machinery Works Nagano
Hiromu C/O Mihara Machinery Works Masuda
Hiroshi Hiroshima Tech. Inst. Mitsubishi Iwata
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 EP0369296A2 publication Critical patent/EP0369296A2/de
Publication of EP0369296A3 publication Critical patent/EP0369296A3/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Withdrawn legal-status Critical Current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
    • 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

Definitions

  • the present invention relates to a paper machine twin-wire former for performing formation of a wet paper sheet between two wires.
  • twin-wire former In a twin-wire former, two wires respectively form loops, and while they are traveling with stock pinched therebetween, moisture is removed from the stock by means of various dewatering instruments, hence gradually a fiber mat grows and a web is formed.
  • the twin-wire former is characterized in that by eliminating a free surface of stock which was present in the paper machine in the prior art, speed-up of a paper machine has been made possible.
  • Stock 1 jetted upwards from a head-box 5 is pinched between two wires consisting of a top wire 3 and a bottom wire 4 which are guided by a forming roll 6 and a breast roll 7, respectively, and it travels along an approximate curved line R on a plurality of shoe blades 2 spaced from one another on the side of the bottom wire 4 which blades are disposed on a curve having a certain radius of curvature R.
  • the stock 1 is subjected to dewatering at an equal rate almost simultaneously on the both surfaces due to the collision energy generated when the stock 1 has collided against the wire 3 and 4, a squeezing effect caused by wire tensions when the stock is pinched between the converging wires 3 and 4, pressure pulses generated by a scraping action of the shoe blades 2 and centrifugal forces, thus a fiber mat grows gradually, and a web is formed successively.
  • a water deflector 8 and a vacuum deflector 9 are held in contact with the top wire 3, and they are devices for removing water discharged from the top wire 3.
  • twin-wire former of shoe type performs initial wet paper sheet formation by making use of pulse-shaped pressure generated by shoe blades provided intermittently as spaced from one another.
  • a yield is poor due to the fact that dewatering is effected simulta­neously at an equal rate to the both sides, also a portion where inter-fiber coupling is little (gap clearance) is formed at the central part of the paper thickness of the finally formed mat, and so, there was a shortcoming that a mechanical strength in the direction of paper thickness (hereinafter called "inter-layer strength”) is low as compared to a system in which dewatering is effected only to one side.
  • the portions where contact points between fibers are few are few as compared to the case of the twin-wire former, and moreover, the portion having a maximum clearance is present at the location close to the paper sheet surface rather than at the central part of the paper thickness. Accordingly, a coupling strength of fibers in the direction of paper thickness is large.
  • the gap clearances close to the surface have the advantage that the press effect is big.
  • a paper machine twin-wire former in which paper stock jetted from a head-box is immediately pinched between two dewatering wires respectively forming loops and formation of a wet paper sheet is performed between the wires, and which former comprises a stationary shoes disposed within the loop of a first wire, supporting the first wire and suppressing dewatering to the side of the first wire, and a dewatering instrument disposed within a second wire loop opposed to the loop of the first wire, supporting the second wire and performing suction dewater­ing to the side of the second wire.
  • a dewatering ratio (a ratio of a removed water to a flow rate of stock jetted from a head-box) to one side exceeds 70%
  • an inter-layer strength would be also improved in proportion to increase of the dewatering ratio, and if the dewatering ratio becomes about 90% or more, an inter-layer strength at almost the same level as a perfectly one-side dewatered paper sheet such as made by the Fourdrinier type wire former, can be obtained.
  • the present invention since within the loop of the first wire is disposed a stationary shoe supporting the first wire and suppressing dewatering to the side of the first wire, dewatering in an early period is effected only to the side of the loop of the second wire opposed to the loop of the first wire.
  • suction dewatering to the side of the loop of the second wire is effected by a dewatering instrument disposed within the loop of the second wire.
  • dewatering is effected as one-side dewatering (assymmetric), thus one-side dewatering is effected up to the dewatering ratio at which the above-mentioned inter-layer strength is improved, and thereby a strength in the thicknesswise direction is improved.
  • the above-described dewatering by means of a stationary shoe is effected up to a mat concentration of about 2 - 3%, and thereafter de­watering is effected on the same side as the dewatering by the stationary shoe, by a suction dewatering action of a dewatering instrument against a filtering resistance of a formed mat to form a dry/wet boundary line.
  • This preferred embodiment comprises a top wire 3 and a bottom wire 4 respectively forming loops, and stock is jetted from a head-box 5 to between a breast roll 7 for guiding the top wire 3 and a homing roll 6 for guid­ing the bottom wire 4, and this stock is adapted to be pinched by the both wires 3 and 4.
  • a dewatering suppression shoe 4 is disposed within the loop of the top wire 3 contiguously to the breast roll 7. As shown in Fig. 2, this shoe 40 is com­posed of a plurality of serrated shoe members 40′ each having a land portion 40′a for supporting the wire and an inclined portion 40′b which forms a wedge-shaped hollow space between the wire surface and its surface on the wire inlet side of each land portion 40a.
  • a first vacuum roll 11 and a transfer box 50 are provided sequentially on the downstream side of the preceding members, and further, on the downstream side of the transfer box 50 is provided a second vacuum roll 30.
  • a return roll 60 for the top wire 3 On the other hand, at a middle position between the aforementioned transfer box 50 and the second vacuum roll 30 is provided a return roll 60 for the top wire 3, and in addition, on the downstream side of the second vacuum roll 30 is provided a suction pick-up roll 12 for sucking a wet paper sheet.
  • Reference numeral 70 designates a save-all disposed within the loop of the bottom wire 4 at the position of the above-described dewatering suction shoe 40. The side of the top wire 3 of the above-described portion of the suction box 10, the first vacuum roll 11 and the transfer box 50, is exposed to the atmosphere.
  • paper stock jetted from a head-box 5 for feeding the paper stock is immediately pinched between two wires, that is, the top wire 3 and the bottom wire 4, and when the paper stock passes the land portion 40′a of the shoe member 40′ in the dewatering suppression shoe 40, due to a reaction force of the wire tension, a pressure is exerted upon the stock between the two wires, and water is squeezed out to the both sides of the two wires.
  • suction boxes 10 and a first vacuum roll 11 are disposed on the downstream side, and by means of these suction boxes 10 and first vacuum roll 11, most of the water contained in the stock is removed to the side of the bottom wire 4.
  • suction boxes 10 and first vacuum roll 11 are disposed on the downstream side.
  • most of the water contained in the stock is removed to the side of the bottom wire 4.
  • a centrifugal force on the rotating vacuum roll a part of dewatering is effected to the side of the top wire 3, and thereby a wet/dry boundary line is formed.
  • dewatering is further ef­fected to the side of the bottom wire by means of the transfer box 50 and the second vacuum roll 30, a web having a mat concentration raised up to 18 - 20% is formed, and the web leaves the bottom wire 4 as sucked by the suction pick-up roll 12 and is conveyed to a press part in the next step of the process.
  • a mass per unit area and a stock concentra­tion are different depending upon the paper sheet to be made, it is desirable to change the arrangement of the dewatering instruments in the former depending upon these paper making conditions.
  • the serrated shoe member 40′ of the dewatering suppression shoe 40 is preferably an ex­tractible blade type member, and in this case as the de­watering ratio can be changes over the range of 50 - 95% by extracting and inserting the shoe member 40′, paper sheet qualities such as an inter-layer strength, two-­facedness, etc. would become controllable.
  • the pressure generated by the configuration, a pitch, etc. of a shoe is different depending upon a stock con­centration, a paper making speed, and so on, it is possible to control the pressure by arraying a plurality of ser­rated shoe members 40′ of different configurations along the direction of flow of the machine.
  • a dewatering suppression shoe in place of the shoe illus­trated in Fig. 2, modified shoes shown in Figs. 3, 4 and 5 can be employed.
  • Fig. 3 shows a serrated shoe member 140 not having land portions
  • Fig. 4 shows a smooth shoe 240 having a given curvature.
  • the radius of curvature R could be constant, it is more desirable to make the radius of curvature successively smaller as the location shifts towards the downstream.
  • Fig. 5 shows a shoe 340 having a plurality of circular-arc-shaped protrusions.
  • the illustrated embodiment of the present invention can present the following advan­tages owing to the combination of the dewatering suppres­sion shoe 40 in the initial dewatering section and the succeeding suction dewatering instruments consisting of the suction boxes 10, the first vacuum roll 11 and the like:
  • FIG. 6 A second preferred embodiment of the present invention is shown in Fig. 6.
  • This modified embodiment is basically composed by arraying the first preferred embodiment on an existing Fourdrinier paper making machine, and so, component parts identical to those of the first preferred embodiment are given like reference numerals.
  • a berm de­flector 9 is provided on the downstream side of the first vacuum roll 11 to control a dewatering ratio, and within the loop of the bottom wire 4 are additionally provided suction box 55.
  • an inter-layer strength of a produced paper sheet can be raised up to the same level as that obtained by a Fourdrinier paper machine despite of being a twin-wire former.

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  • Paper (AREA)
EP19890120612 1988-11-14 1989-11-07 Doppelsieb-Papiermaschine Withdrawn EP0369296A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP28587188A JPH02133689A (ja) 1988-11-14 1988-11-14 抄紙機ツインワイヤホーマ
JP285871/88 1988-11-14

Publications (2)

Publication Number Publication Date
EP0369296A2 true EP0369296A2 (de) 1990-05-23
EP0369296A3 EP0369296A3 (de) 1991-12-04

Family

ID=17697115

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890120612 Withdrawn EP0369296A3 (de) 1988-11-14 1989-11-07 Doppelsieb-Papiermaschine

Country Status (3)

Country Link
EP (1) EP0369296A3 (de)
JP (1) JPH02133689A (de)
FI (1) FI895367A0 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4102065A1 (de) * 1991-01-24 1992-07-30 Escher Wyss Gmbh Doppelsiebformer
DE4332162A1 (de) * 1993-09-22 1994-02-03 Voith Gmbh J M Doppelsiebformer einer Papiermaschine
EP0471469B1 (de) * 1990-07-30 1996-05-08 Mitsubishi Jukogyo Kabushiki Kaisha Blattbildende Vorrichtung für eine Papiermaschine
EP0872590A2 (de) * 1997-04-15 1998-10-21 Mitsubishi Heavy Industries, Ltd. Entwässerungsvorrichtung für einen Doppelsiebformer in einer Papiermaschine
WO2002072950A1 (de) * 2001-03-13 2002-09-19 Voith Paper Patent Gmbh Doppelsiebformer
AT506986B1 (de) * 2008-06-19 2012-09-15 Metso Paper Inc Verfahren in verbindung mit einer papiermaschine und eine papiermaschine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5248392A (en) * 1990-07-30 1993-09-28 Mitsubishi Jukogyo Kabushiki Kaisha Sheet-forming apparatus for a twin wire paper machine with positive pulse shoe blades
JP3181202B2 (ja) * 1995-03-27 2001-07-03 三菱重工業株式会社 抄紙機ツインワイヤフォーマの脱水機器
CA2342023C (en) * 2000-04-10 2007-07-03 Randox Laboratories Ltd. Paramagnetic particle detection

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2977277A (en) * 1957-07-15 1961-03-28 Pusey & Jones Corp Method and apparatus for making a web of fibrous material
FR2072936A5 (en) * 1969-12-06 1971-09-24 Walmsleys Bury Ltd Apparatus for fabricating laminated paper - or cardboard
US3855057A (en) * 1967-11-02 1974-12-17 Beloit Corp Paper formation utilizing a large diameter suction roll
DE2531839A1 (de) * 1974-07-18 1976-02-05 Valmet Oy Doppelsiebteil in einer papiermaschine
DE3329833A1 (de) * 1982-08-23 1984-03-01 A. Ahlström Oy, 29600 Noormarkku Vorrichtung zur beeinflussung einer auf einem sieb entwaesserten bahn
EP0177439A2 (de) * 1984-10-03 1986-04-09 Research Association of Pulp and Paper Technology Vorrichtung zum Formen einer Papierbahn

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2977277A (en) * 1957-07-15 1961-03-28 Pusey & Jones Corp Method and apparatus for making a web of fibrous material
US3855057A (en) * 1967-11-02 1974-12-17 Beloit Corp Paper formation utilizing a large diameter suction roll
FR2072936A5 (en) * 1969-12-06 1971-09-24 Walmsleys Bury Ltd Apparatus for fabricating laminated paper - or cardboard
DE2531839A1 (de) * 1974-07-18 1976-02-05 Valmet Oy Doppelsiebteil in einer papiermaschine
DE3329833A1 (de) * 1982-08-23 1984-03-01 A. Ahlström Oy, 29600 Noormarkku Vorrichtung zur beeinflussung einer auf einem sieb entwaesserten bahn
EP0177439A2 (de) * 1984-10-03 1986-04-09 Research Association of Pulp and Paper Technology Vorrichtung zum Formen einer Papierbahn

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0471469B1 (de) * 1990-07-30 1996-05-08 Mitsubishi Jukogyo Kabushiki Kaisha Blattbildende Vorrichtung für eine Papiermaschine
DE4102065A1 (de) * 1991-01-24 1992-07-30 Escher Wyss Gmbh Doppelsiebformer
DE4332162A1 (de) * 1993-09-22 1994-02-03 Voith Gmbh J M Doppelsiebformer einer Papiermaschine
DE4497054C1 (de) * 1993-09-22 1997-02-27 Voith Gmbh J M Doppelsiebformer einer Papiermaschine
DE4497054C2 (de) * 1993-09-22 1999-04-29 Voith Gmbh J M Doppelsiebformer einer Papiermaschine
EP0872590A2 (de) * 1997-04-15 1998-10-21 Mitsubishi Heavy Industries, Ltd. Entwässerungsvorrichtung für einen Doppelsiebformer in einer Papiermaschine
EP0872590A3 (de) * 1997-04-15 1999-06-02 Mitsubishi Heavy Industries, Ltd. Entwässerungsvorrichtung für einen Doppelsiebformer in einer Papiermaschine
US6309511B1 (en) 1997-04-15 2001-10-30 Mitsubishi Heavy Industries, Ltd. Dewatering instrument for a paper machine twin-wire former
WO2002072950A1 (de) * 2001-03-13 2002-09-19 Voith Paper Patent Gmbh Doppelsiebformer
US7067042B2 (en) 2001-03-13 2006-06-27 Voith Paper Patent Gmbh Twin wire former
AT506986B1 (de) * 2008-06-19 2012-09-15 Metso Paper Inc Verfahren in verbindung mit einer papiermaschine und eine papiermaschine

Also Published As

Publication number Publication date
JPH02133689A (ja) 1990-05-22
FI895367A0 (fi) 1989-11-10
EP0369296A3 (de) 1991-12-04

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