WO1987006637A1 - Appareil de formation d'une bande de papier - Google Patents

Appareil de formation d'une bande de papier Download PDF

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Publication number
WO1987006637A1
WO1987006637A1 PCT/US1986/000975 US8600975W WO8706637A1 WO 1987006637 A1 WO1987006637 A1 WO 1987006637A1 US 8600975 W US8600975 W US 8600975W WO 8706637 A1 WO8706637 A1 WO 8706637A1
Authority
WO
WIPO (PCT)
Prior art keywords
wire
stock
web
forming section
forming
Prior art date
Application number
PCT/US1986/000975
Other languages
English (en)
Inventor
Merle W. North
Original Assignee
Beloit Corporation
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 Corporation filed Critical Beloit Corporation
Priority to JP50302586A priority Critical patent/JPH01502388A/ja
Priority to PCT/US1986/000975 priority patent/WO1987006637A1/fr
Priority to CA000532958A priority patent/CA1278207C/fr
Publication of WO1987006637A1 publication Critical patent/WO1987006637A1/fr
Priority to US07/127,525 priority patent/US4894120A/en

Links

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

  • This invention relates to a forming apparatus for forming a web from stock. More particularly, this invention relates to a forming apparatus for forming a web of paper in the forming section of a papermaking machine.
  • Paper webs formed as a result of the foregoing fourdriner forming process resulted in a finished paper product exhibiting a certain two-si dedness in that the water, during formation, had been drained in one direction only.
  • Such two-si dedness presented a finished sheet having different surface charac ⁇ teristics on each side of the sheet thereby causing printing probl ems .
  • twin wire formers have been pro ⁇ posed which have enabled the dewatering of a web in both directions simultaneously.
  • Such twin wire formers have greatly increased the quality of the resultant paper product by providing a web having fairly uniform surface character ⁇ istics on both sides thereof.
  • twin wire formers are disposed as retro ⁇ fits above an existing fourdrinier forming section.
  • the jet from the headbox is deposited on the moving fourdrinier wire and usually travels a considerable - distance prior to entering the forming section defined by the cooperating bottom and top wire.
  • the web is subjected only to bottom drainage.
  • bottom drainage has resulted in certain inherent character ⁇ istics of the resultant paper web and these characteristics have, to a large degree, been undesirable.
  • twin wire formers it is difficult to apply a gradual dewatering action to the stock so that the resultant web maintains therein, most of the fines that were suspended in the stock.
  • Another objective of the present invention is the pro ⁇ vision of a forming apparatus in which the stock is subjected simultaneously to a gradual increase in dewatering action be ⁇ tween the first and second ends of the forming section.
  • Another objective of the present invention is the pro ⁇ vision of a forming apparatus in which the jet of stock is ejected directly into the forming section defined between a first and a second forming wire.
  • Another objective of the present invention is the pro ⁇ vision of a forming apparatus in which the jet of stock is directed slightly towards the lower forming wire.
  • Another objective of the present invention is the pro ⁇ vision of a forming apparatus including a first and second co ⁇ operating wire with a suction shoe disposed below the first wire and adjacent to the first end of the forming section for dewatering the web downwardly.
  • Another objective of the present invention is the pro ⁇ vision of a dewatering shoe having a large radius of curvature such that a first portion of water is removed through the first wire and a second portion of water is removed upwardly through the second wire.
  • Another objective of the present invention is the pro ⁇ vision of a forming apparatus including a suction slot for removing the second portion of water..
  • Another objective of the present invention is the pro ⁇ vision of a suction roll disposed below the first wire with the roll having a radius of curvature which is less than the radius of curvature of the suction shoe such that a third portion of water is removed from the stock through the second wire.
  • Another objective of the present invention is the pro ⁇ vision of a forming apparatus in which the roll is a grooved roll .
  • Another objective of the present invention is the pro ⁇ vision ⁇ f a forming apparatus in which the roll is disposed above the second wire such that the third portion of water is removed through the first wire.
  • the present invention relates to a forming apparatus and method for forming a web of paper from paper stock.
  • the apparatus includes a frame means and a plurality of guide rolls rotatably connected to the frame means.
  • a first continuous forming wire extends around, and is guided by, the first plurality of rolls.
  • the second plurality of guide rolls is rotatably connected to the frame means and a second continuous wire extends around, a.nd is guided by, the second plurality of rolls.
  • the first and second wires cooperate together to define therebetween a forming section in which the web is formed, the forming sec ⁇ tion having a first and a second end.
  • a headbox is disposed adjacent to the first end of the forming section such that the stock is ejected from the headbox towards the first end of the forming section so that the stock moves together with, and between, the wires and along the forming section in a direction from the first towards the second end of the forming section.
  • a dewatering shoe is disposed adjacent to the first end of the forming section for dewatering the web. The de ⁇ watering shoe defines a curved surface which abuts against the first wire.
  • the curved surface has a center of curvature which is disposed on the opposite side of the first wire rela ⁇ tive to the second wire such that the first portion of water is removed from the stock through the first wire and a second portion of water is removed from the stock through the second wire due to the centrifugal force of the stock moving along the curved surface.
  • a suction slot is dis ⁇ posed adjacent to the second wire for collecting the second portion of water.
  • a roll means is disposed between the suction slot collector means and the second end of the forming section.
  • the roll means has a radius of curvature which is less than the radius of curvature of the dewatering means so that a third portion of water is removed from the stock as the stock passes around the roll means such that the dewatering of the stock from the first toward the second end of the forming section gradually increases so that the removal of fines from the stock is minimized and two-sided- ness of the resultant web is inhibited.
  • the roll means is a suction roll whereas in a second embodiment of the present invention, the roll means is a polymeric-covered, grooved roll .
  • the roll means is disposed beneath the first wire such that as ' the second wire passes around the roll means, the third portion of water is removed from the stock through the first wire.
  • Figure 1 is a side elevational view of the forming apparatus of the present nvention.
  • Figure 2 is an enlarged side elevational view of a portion of the apparatus shown in figure 1.
  • Figure 3 is an enlarged side elevational view of a further embodiment of the present invention.
  • Figure 4 is an enlarged side elevational view of yet another embodiment of the present invention showing the roll disposed above the second wire.
  • Figure 1 shows a forming apparatus generally designated 10 for forming a web W from stock contained within a headbox 12.
  • the apparatus 10 includes a frame means generally designated 14 and a first plurality of guide rolls, 16,17,18,19,20,21 ,22,23, 24,25 and 26 which are rotatably connected to the frame means 14.
  • a first continuous forming wire 28 extends around the guide rolls 16 to 26.
  • a second plurality of guide rolls, 30, 3.1 ,32,33 and 34 are rotatably connected to the frame means 14.
  • a second continuous forming wire 36 extends around, and is guided by, the second plurality of rolls 30 to 34. The first and second wires 28 and 36 cooperate together to define there ⁇ between, a forming section 38 in which the web W is formed.
  • the forming section 38 has -a first and second end 40 and 42 respectively.
  • the headbox 12 is disposed adjacent to the first end 40 of the forming section 38 such that stock is ejected from the headbox 12 toward the first end 40 of the forming section 38 so that stock travels between the first and second wires 28 and 36 and along the forming section 38.
  • the headbox 12 is a hydraulic headbox which delivers a uniform jet of stock.
  • the headbox 12 is preferably disposed less than 13 inches (33 centimeters) from the first end 40 of the forming section 38.
  • the headbox 12 is dis ⁇ posed 12 inches or less from the first end 40 of the forming section 38.
  • the jet of stock impinges onto the first wire 28 prior to the second wire 36 and, in the preferred embodiment o the present invention, the jet is arranged to impinge onto the first wire 28 at an angle within the range 1 to 5 degrees rela ⁇ tive to the forming section 38 adjacent to the first end 4 Q of the forming section 38.
  • Figure 2 is an enlarged side view of the forming section
  • the dewatering means 44 is disposed adjacent to the first wire 28 with the first wire 28 and the formed web W disposed between the dewatering means 44 and the second wire 36.
  • the dewatering means 44 defines a curved surface 46 which has a center of curvature 46R.
  • the surface 46 has a radius of curvature in the order of 200 inches (508 centimeters) with such center of curvature 46R being disposed on the opposite side of the web W relative to the second wire 36.
  • the curved surface 46 defines a plurality of drainage holes 48,49,50 and 51 such that water within the web W drains through the first wire 28 and through the holes 48 to 51 for effecting initial dewatering of the formed web W.
  • a partial vacuum which is connected to the dewatering means 44.
  • a partial vacuum of between 10 to 20 in ⁇ hes of water is applied to the dewatering means 44.
  • a roll means 17 is a suction roll which is disposed between the collector means 52 and the second end 42 of the forming section 38.
  • the roll means 17 has a radius of curva ⁇ ture which is less than the radius of curvature of the de ⁇ watering means 44.
  • the roll means 17 is disposed on the same side of the first wire 28 as the dewatering means 44. That is, the roll means 17 is disposed under the first wire 28 such ti ⁇ a.t when the first wire 28 moves around the roll means 17, a third portion of water is removed from the stock through the second wire 36 as the stock passes around the roll means 17.
  • Figure 3 shows an alternative embodiment of the present invention in which a polymeric-covered, grooved roll 17A is substituted for the suction roll 17 of the first embodiment.
  • a polymeric-covered, grooved roll 17A results in a reduction of cost as grooved rolls are less costly to manufacture than suction rolls. How ⁇ ever, such substitution does not greatly reduce the efficiency of the present forming apparatus.
  • a radius top suction box 54 is shown below the first wire and between the collector means and the roll means for further reducing the moisture content of the formed web by removing water through the fi rst wi re .
  • Figure 4 shows yet a further embodiment of the present invention in which the roll means 17B, which may be a grooved roll , is disposed above the second wire 36B so that as the second wire 36B passes around the roll means 17B the third portion of water is removed from the stock through the first wire 28B.
  • the roll means 17B which may be a grooved roll
  • a jet of stock is directed from the headbox 12 towards the first end 40 of the forming section 38.
  • the stock disposed between the first and second wires 28 and 36 respectively, moves towards the suction shoe 44 which is disposed below the first wire 28.
  • the partial vacuum within the suction shoe 44 causes a gentle dewatering of the stock disposed between the first and second wire.
  • a second portion of water will be removed from the moving stock through the second wire 36 due to the centrifugal force of the stock moving around the curved surface 46.
  • Such second portion of water is removed through the second wire 36 by means of the collector means, or vacuum slot 52.
  • the formed web disposed between the first and second wires 28 and 36 passes around the roll means, or suction roll 17 which is disposed below the first wire 28.
  • the suction roll applies a greater suction to the moving wires and stock than the suction applied by the suction shoe 44 so that some of the remaining water within the formed web is drawn through the first wire 28 towards the suction roll 17.
  • the suction roll 17 has a radius of curvature which is less than the radius of curvature of the suction shoe 44, therefore, as the stock passes around the suction roll 17, some of the water within the stock is thrown by centrifugal force upwardly through the second wire 36. Therefore, the third portion of water rem ⁇ ved.
  • figure 4 shows the roll means 17B which may be a grooved roll similar to the grooved roll 17A of figure 3, but with the roll means 17B disposed above the second wire 36B.

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  • Paper (AREA)

Abstract

Est décrit un appareil de formation (10) destiné à former une bande de papier à partir d'une masse de matière brute. L'appareil (10) comprend un bâti (14) et une première et une seconde pluralités de cylindres de guidage (16-26 et 30-34) montés de manière rotative sur le bâti (14). Une première et une seconde toiles de formation (28, 36) s'étendent respectivement autour des première et seconde pluralités de cylindres de guidage, les première et seconde toiles (28, 36) coopérant pour définir entre elles une section de formation (38) ayant une première et une seconde extrémités (40, 42). Un bac de tête (12) est disposé adjacent à la première extrémité (40) de la section de formation (38). Un patin aspirant (44) est disposé adjacent à la première extrémité (40) de la section de formation pour effectuer une déshydratation initiale de la bande de papier. Le patin aspirant (44) présente une surface courbe (46) qui s'appuie contre la première toile (28) pour extraire une première quantité d'eau au travers de la première toile (28) et une seconde quantité d'eau au travers de la seconde toile (36). Une fente à vide (52) récupère la seconde quantité d'eau et un cylindre (17) est disposé entre la fente à vide (52) et la seconde extrémité (42) de la section de formation (38) pour extraire une troisième quantité d'eau de la bande formée, ce qui se traduit par une augmentation progressive de la déshydratation depuis la première extrémité vers la deuxième extrémité de la section de formation (38), ce qui permet de réduire au minimum l'opération d'extraction des fines de la matière brute et d'empêcher la formation de deux faces sur la bande résultante.
PCT/US1986/000975 1986-04-30 1986-04-30 Appareil de formation d'une bande de papier WO1987006637A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP50302586A JPH01502388A (ja) 1986-04-30 1986-04-30 ウェブ形成装置
PCT/US1986/000975 WO1987006637A1 (fr) 1986-04-30 1986-04-30 Appareil de formation d'une bande de papier
CA000532958A CA1278207C (fr) 1986-04-30 1987-03-25 Dispositif de fabrication du papier
US07/127,525 US4894120A (en) 1986-04-30 1987-12-02 Twin wire forming apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1986/000975 WO1987006637A1 (fr) 1986-04-30 1986-04-30 Appareil de formation d'une bande de papier

Publications (1)

Publication Number Publication Date
WO1987006637A1 true WO1987006637A1 (fr) 1987-11-05

Family

ID=22195486

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1986/000975 WO1987006637A1 (fr) 1986-04-30 1986-04-30 Appareil de formation d'une bande de papier

Country Status (2)

Country Link
JP (1) JPH01502388A (fr)
WO (1) WO1987006637A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989011000A1 (fr) * 1988-05-06 1989-11-16 J.M. Voith Gmbh Formeur a deux toiles et procede pour fabriquer une bande continue de matiere fibreuse
AT399356B (de) * 1991-05-29 1995-04-25 Voith Gmbh J M Doppelsiebformer für eine papiermaschine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3726758A (en) * 1971-07-08 1973-04-10 J Parker Twin-wire web forming system with dewatering by centrifugal forces
DE3501312A1 (de) * 1984-01-20 1985-07-25 Valmet Oy, Helsinki Verfahren und vorrichtung zur bildung einer papierbahn
EP0160615A2 (fr) * 1984-05-03 1985-11-06 Beloit Corporation Section de formage à double toile

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3726758A (en) * 1971-07-08 1973-04-10 J Parker Twin-wire web forming system with dewatering by centrifugal forces
DE3501312A1 (de) * 1984-01-20 1985-07-25 Valmet Oy, Helsinki Verfahren und vorrichtung zur bildung einer papierbahn
EP0160615A2 (fr) * 1984-05-03 1985-11-06 Beloit Corporation Section de formage à double toile

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989011000A1 (fr) * 1988-05-06 1989-11-16 J.M. Voith Gmbh Formeur a deux toiles et procede pour fabriquer une bande continue de matiere fibreuse
US5141600A (en) * 1988-05-06 1992-08-25 J. M. Voith Gmbh Twin-wire former
AT399356B (de) * 1991-05-29 1995-04-25 Voith Gmbh J M Doppelsiebformer für eine papiermaschine

Also Published As

Publication number Publication date
JPH01502388A (ja) 1989-08-17

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