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
• • 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
  • D21F1/36—Guiding mechanisms
  • D21F1/40—Rolls
• • 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
  • D21F3/08—Pressure rolls
  • D21F3/086—Pressure rolls having a grooved surface
• • 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
  • D21F9/04—Complete machines for making continuous webs of paper of the cylinder type
  • D21F9/046—Complete machines for making continuous webs of paper of the cylinder type with non-immersed cylinder

Definitions

• the invention relates to a device according to the preamble of claim 1.
• a device is known from DS-AS 28 10 692.
• a support element is arranged there behind a guide roller, which can be designed as a suction box.
• This support element protrudes with an acute-angled edge into the wedge-shaped space between the roller jacket and the sieve belt.
• Its outer surface facing the roller shell can be regarded as a water guiding surface.
• a similar known device with a water guiding element is described in US Pat. No. 3,065,789.
• register rollers of a Fourdrinier paper machine Such a register roller always has a solid roller shell and is only touched by the linear sieve belt, but not wrapped around it.
• the US-PS is based on the fact that a vacuum is created in the wedge-shaped space between such a register roller and the running screen belt, the level of which depends on the intensity of the dewatering of the paper web. It is found that with increasing screen speed, the vacuum can become so high that the dewatering is too intensive.
• the water guiding element provided there is therefore used, in addition to guiding the water, above all to adjust the intensity of the drainage. For this purpose, it can be adjusted parallel to the direction of wire travel, the distance between the acute-angled edge and the discharge line of the wire belt changing from the register roller. Otherwise, the known water guiding element has a bar guiding the sieve belt.
• the invention has the case that the dewatering of the paper web takes place in the area of the wrapping of the guide roller.
• the water extracted from the paper web first penetrates into the recesses provided on the roll jacket of the guide roll. Behind the discharge line of the screen belt of the guide orphan, at least some of this water is then thrown out of the guide roller again. It is difficult to remove this water to lead. This is because there is a tendency that part of this water continues to run with the sieve belt and another part with. the guide roller. Attempts have been made to overcome these difficulties by designing the guide roller as a suction roller. However, the water was heavily nebulized. The difficulties mentioned increase with the speed of the paper machine.
• the invention has for its object to improve the device specified in the preamble of claim 1 to the extent that the water emerging from the guide roller can be discharged without problems even at the highest paper machine speeds.
• the water to be discharged forms a very compact jet which can easily be guided into a collecting heater or the like.
• the effect of the arrangement according to the invention is based on the fact that the guidance of the water particles begins immediately after the point of drainage before any significant nebulization occurs, that is, before air can enter the wedge-shaped space.
• the advantages mentioned can be used in many paper machines in that the overall dimensions of the paper machine become smaller, in particular the overall height. This not only reduces the manufacturing costs for the paper machine, but also the building costs.
• the guide roller of the arrangement according to the invention can e.g. take the place of a breast roll of a paper machine, e.g. on the headbox of a tissue paper machine.
• it can be designed as a suction roll or as a self-winding roller. In all of these cases, the guide roller is only wrapped by a single screen belt.
• twin wire formers the guide roller of the arrangement according to the invention taking the place of the so-called forming roller. This is wrapped in two sieve belts, between which the paper web to be dewatered is located.
• Twin wire formers of various types that are suitable for this are known per se, e.g. from DE-PS 21 05 613 or from the magazine "Wochenblatt für Textilfabrikation" 1980, page 898.
• the guide roller is designed in the manner of a suction roller. It is important that the box arranged in the interior of the roll shell is arranged relative to the pointed edge of the water guiding element in such a way as is specified in feature c) of claim 4. Surprisingly, it has been shown that when this arrangement is operated, a vacuum is created in the box itself. This vacuum can improve the effect of the arrangement according to the invention in various applications; ie the removal of the white water is now completely problem-free. In other words, claim 5 states that the guide roller has no suction connections. In special cases, however, the vacuum generated by the arrangement according to the invention may not be sufficient. In this case, the vacuum can be increased with the aid of a suction device. It is also possible that in addition to the box specified in claim 4, in which a vacuum is automatically set, a further suction box is arranged. In all cases, thanks to the invention, it is necessary to apply less negative pressure than previously. Energy savings are thus achieved.
• Figure 1 is a partial longitudinal section through a twin wire former.
• FIG. 2 shows a schematic partial longitudinal section through the initial part of the wire section of a tissue paper machine
• Fig. 3 shows a partial longitudinal section through a twin wire former deviating from Fig. 1.
• Fig. 1 can be seen from a twin wire former, a lower wire 10 and an upper wire 11, which together wrap a guide roller 12 and immediately afterwards run over a water guide element 13, which is combined with a suction box 14.
• the guide roller 12, generally called “forming roller”, has a perforated roller jacket 15 and a suction box 16 with two suction chambers 17 and 18.
• the water guiding element 13, also called “jet guide shoe” is arranged in the wedge-shaped space that is between the roller jacket 15 and the sieve belts 10 and 11 running off the roller 12.
• the water guide element 13 protrudes with a pointed edge 20 in the aforementioned inter mediate space and has a facing the roller shell 15 What ser guide surface 21.
• the distance between the water guide surface 21 and the roller shell 15 is initially, ie te at the Spitzkan 20, quite small; it increases slightly but continuously in the direction of rotation of the roll shell. Finally, as shown in Fig. 1, it can pass into the cover wall of a white water tub 19.
• the common drain line of the two screen belts 10 and 11 from the roller jacket 15 is shown in FIG. 1 by point 22.
• the distance a between the drain line 22 and the pointed edge 20 of the jet guide shoe 13 is only about 15% of the outer diameter D of the forming roller 12. This ensures that the white water emerging from the bores of the roller jacket 15 as a compact jet 23 along the guide surface 21st flows and comes into the white water tank 19 without any significant mixing with air. This creates a vacuum in the chamber 18, even when it is not being sucked in from the outside. So you will generally only have to generate negative pressure in the first chamber 17 from the outside.
• the second longitudinal wall 28 of the second box 18 with its sealing strip 29 is arranged in the region of the pointed edge 20, as seen in the direction of rotation of the roll shell 15.
• the sealing strip 29 has an inlet edge 31 and an outlet edge 32.
• the sealing strip 29 is expediently arranged in such a way that the inlet edge 31 lies in front of the pointed edge 20 and the outlet edge 32 behind it, as seen in the circumferential direction of the roller shell 15.
• the jet guide shoe 13 also serves as a screen guide element.
• the screen guide surface will therefore preferably be equipped with a wear-resistant covering. This is not particularly emphasized in the drawing.
• the guide roller 42 is a breast roller, which is assigned to a headbox 40 and is wrapped only by a single screen 41.
• a beam guide shoe 43 which corresponds in its essential features to the beam guide shoe 13 of FIG. 1.
• the sieve 41 runs behind the jet guide shoe 43 together with the paper web formed and together with another sieve belt 44 on a Formie roller 39.
• a white water tub is designated 49.
• the breast roll 42 can have a perforated roll cover 45 and. have a suction box 46 arranged therein. Instead of the suction box, however, only one sealing strip 48 can also be arranged in the area between the drain line 52 and the pointed edge 50 of the jet guide shoe 43. This is in Flg. 2 indicated by dash-dotted lines. With such a sealing strip can be achieved in a similar manner as with the help of negative pressure that the white water located in the holes in the roll shell is only flung out a certain distance behind the drain line 52 from the roll shell 45.
• the guide roller 12 or 42 can also be provided with a non-perforated roller jacket. It is sufficient if the roller shell has depressions, for example blind bores, from the outside. It is only essential that a storage volume for the white water is provided in some way.
• the two screens 10 and 11 run in the direction from bottom to top over the forming roller 12. However, deviations can also be made from this.
• the arrangement according to FIG. 1 can be turned upside down. One would then only have to redesign the white water tank 19 in such a way that its outlet opening would again be arranged in the lower region. The effect of the beam guide shoe 13 is unchanged in this arrangement.
• the invention is also applicable in a papermachine roller press, in particular when larger amounts of water pass through a press nip (with or without paper) in recesses of a press roller and are spun off behind the press nip.
• FIG. 3 shows possibilities of how the twin wire former shown in FIG. 1 can be modified.
• the unchanged details are denoted by the same digits as in Fig.
• a honeycomb cover 35 is composed of strips standing upright, preferably straight strips that run in the circumferential direction, and zigzag strips between each other the straight bands.
• a honeycomb cover is known from DE-AS 21 4836I. From this document it is also known to provide openings in the belts which allow a honeycomb-to-honeycomb flow in the circumferential direction of the forming roller 12 '.
• Such a honeycomb cover is used according to a further concept of the invention (claim 11).
• Another advantageous embodiment of the invention consists in that the water guiding surface 21 'extends at least over a certain part of its extent in the circumferential direction approximately parallel to the lateral surface of the guide roller (e.g. 15', 35) (radius R).

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Publications (1)

Family

ID=6134430

Family Applications (1)

Country Status (5)

Cited By (4)

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Citations (9)

Family Cites Families (7)

• 1981
  • 1981-06-11 DE DE3123131A patent/DE3123131C2/de not_active Expired
• 1982
  • 1982-05-29 WO PCT/EP1982/000115 patent/WO1982004450A1/en active IP Right Grant
  • 1982-05-29 JP JP57501885A patent/JPS58500903A/ja active Granted
• 1983
  • 1983-01-17 FI FI830149A patent/FI80088C/fi not_active IP Right Cessation
  • 1983-02-10 SE SE8300705A patent/SE447918B/sv not_active IP Right Cessation

Patent Citations (9)

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