EP1637648B1 - Press section of a machine for producing a paper or board web - Google Patents

Abstract

In a sheet producing machine comprising a press part (1) with presses (4.1 to 4.6), an upstream sheet forming sieve part (2), a downstream drying part (3), a seating (7) with a longitudinally extending support construction (SC) on each of the drive and guide sides, rollers (4.1 to 4.6; 5.4 to 5.19) mounted in the SC's and felt bands (6.1 to 6.4) wound around the rollers and having open and closed transverse seams, each SC extends over at least two rollers in the press part in the longitudinal direction and is a single piece in the longitudinal direction and the two SC's are free of removable distancing pieces.

Description

The invention relates to a machine for producing a web of paper or cardboard.

A paper machine comprises as essential assemblies a headbox, a wire section on which the web is formed, a downstream press section and an adjoining dryer section with a roll apparatus.

The press section has a plurality of rollers, which are arranged in different configurations relative to each other and form one or more press nips with each other. An essential part of the press section are felt belts, which are passed together with the still moist paper web through the press nips and absorb water there. The water stored in the felt is released again elsewhere.

Like all other components of the paper machine, the press section has a stiffening. This includes on the drive side as well as on the Führe rseite each a support structure. The rollers mentioned are stored in the supporting structures.

The felt belts are heavily exposed to wear. They must therefore be frequently replaced. The removal of the worn felt tape is this problem, since the band can be cut. It is different with the putting on of a new felt tape. The felt is available as an endless belt. In order to mount it on a plurality of rollers, a part of one of the two supporting structures, a so-called spacer, must be taken out of this supporting structure so that the rollers in the other supporting structure are temporarily cantilevered - so-called cantilever principle.

After mounting the felt belt, the spacer is re-inserted into the relevant supporting structure so that the machine can be put into operation again with a new felt belt or with new felt belts.

The whole process is time consuming. Longer production breaks are necessary. In addition, a cantilever construction claimed a large amount of space on the drive side. A very decisive disadvantage, however, is that the stability of the strangulation is weakened by the separation points with their spacers or with swing-out straps, as they can not be performed as stable because of the need for a simple and quick change possibility, as the rest of the feces. The operating speeds of modern paper machines are known to be high, and the working widths are known to be large. This increases the risk of self-oscillation of the stiffening. This has a negative effect on the operation of the paper machine and on the quality properties of the paper web. The entire leader-side restraint must be designed according to the requirements of the Filzwechsels. The provision of spacers leads to a construction of the stiffening parts, which does not guarantee optimal rigidity.

Also, the leadership of the felt belts is not arbitrary, but depends on the requirements of the feeding. Tension rollers must have a large stroke, which in turn requires space. To pull in the felt tapes must be pre-draped, which brings with it the risk of damaging edges and corners of the stench.

A machine according to the preamble of claim 1 is known from US-A-5,256,256 or the EP-A-0287543 known.

The invention has for its object to make a machine of the type mentioned in such a way that the stench has no weaknesses, as in the cantilever design, and that they can thus be more stable than before. As a result, the machine should become self-oscillating free of problems. Pulling in coverings should be faster than previously possible.

This object is solved by the features of claim 1. Accordingly, the felt belts are provided with openable and closable cross seams. The felt belt, which is ready to be pulled into the press section, is therefore initially not an endless belt. This means that the single felt belt can be looped around the respective group of rolls - press rolls, guide rolls and so on - in a completely closed state without any spacers. Then, the two ends are joined together and connected by a seam. The laying of a seam is unproblematic and easy and quick to perform in the current state of the art.

As the chair is free of removable spacers, it is also free of weak points. Overall, it can be structurally designed solely on the basis of the necessary rigidity, so that vibrations due to natural frequency can be avoided. It eliminates any components that are necessary in the cantilever design, namely cantilever beam, bending beams. Accordingly, the space requirement on the drive side can also be reduced.

The further measure according to the invention is to dimension the two supporting structures - one on the drive side and one on the leader side of the press section - in the longitudinal direction such that they extend without interruption over at least some of the presses, or extend over the entire press section. Each support structure is thus completely or largely in one piece in the longitudinal direction. It is to be understood by the one-piece, that they may well be composed of two or more components, provided that the components are assembled with the necessary robustness, so that the necessary rigidity arises as if the support structure consist of only a single component.

The two lateral support structures of the chair can be divided in the vertical direction. However, it is expedient to provide a one-piece construction also in the vertical direction. The most important thing, however, is that the single, longitudinally extending support structure effectively extends as a bridge across the entire press section.

Of course, the press section can also comprise a compact press arrangement with a central roll, on which two or more press nips are formed.

In addition, not the entire press section must be constructed on the principle of cantilever freedom. Rather, for example, a press can be provided, which is stored according to the cantilever principle and accordingly provided with an endless belt.

• Für Neuanlagen sind keine Hilfsträger für den Bespannungswechsel mehr notwendig.
• Es treten keine Cantileverkräfte auf, die ins Gebäude eingeleitet werden müssen.
• Der Raumbedarf auf der Triebseite ist geringer und die Gebäudekosten sind demgemäß niedrig.
• Die Bespannung lässt sich leicht und schnell wechseln, da keine Zwischenstücke demontiert werden müssen.
• Leitwalzen müssen zum Zwecke des Filzwechsels nicht versetzt werden - im Gegensatz zur konventionellen Bauweise; es entfallen die bisher notwendigen Hubwerke.
• Bei der Konstruktion der führerseitigen Stuhlungsteile (Tragkonstruktionen) können die Bedürfnisse des Filzwechsels außer Betracht bleiben. Deshalb kann die Stuhlung auf der Führerseite massiver und steifer gestaltet werden.
• Die Pressenstuhlung und die Trockenpartiestuhlung lassen sich durch relativ tiefliegende und steife Verbindungstraversen miteinander verbinden.
• Die dynamische Stabilität der Stuhlung ist größer, was zu einer höheren ersten Eigenfrequenz in Maschinenrichtung führt.
• Die konstruktiven Lösungen der Filzführung, insbesondere der Oberfilzführung, sind nicht mehr durch Trennfugen in der Stuhlung bestimmt. Sie können stattdessen prozessoptimiert gestaltet werden. Dies betrifft vor allem den Bereich der Filzkonditionierung und der Filzspannung.
• Filzleitwalzen des zweiten Oberfilzes können direkt an den Ständer zum ersten Trockenzylinder angeschraubt werden.
• Es sind keine oder weniger Querverrohrungen zwischen Triebseite und Führerseite notwendig, so wie bisher; stattdessen können Versorgungsleitungen für Öl, Wasser, Luft nunmehr direkt auf der Führerseite vom Maschinenkeller hochgeführt werden; desgleichen lassen sich Öl- und Wasserabläufe direkt in den Keller hinabführen; ein Abkoppeln von Ölabläufen beim Filzwechsel entfällt.
• Die Lagerbefestigungen der Leitwalzenlager lassen sich allein nach statischen Gesichtspunkten auswählen, ohne Rücksichtnahme auf Gesichtspunkte des Filzwechsels.

The advantages of the invention can be summarized as follows:

• For new plants, no subcarrier for the change of clothing more necessary.
• There are no cantilever forces that need to be injected into the building.
• The space requirement on the drive side is lower and the building costs are accordingly low.
• The covering can be easily and quickly changed, since no intermediate pieces must be dismantled.
• Guide rollers do not need to be offset for the purpose of filament change - in contrast to conventional construction; it eliminates the previously necessary hoists.
• In the design of the leader-side stirrup parts (supporting structures), the needs of Filzwechsels can be disregarded. Therefore, the stiffening on the driver's side can be made more massive and stiffer.
• The press chair and the dry party chair can be interconnected by relatively low-lying and rigid connecting beams.
• The dynamic stability of the stiffening is greater, resulting in a higher first natural frequency in the machine direction.
• The constructive solutions of the felt guide, in particular the upper felt guide, are no longer determined by joints in the stiffening. They can instead be designed to be process-optimized. This applies above all to the area of felt conditioning and felt tension.
• Filzleitwalzen the second upper felt can be screwed directly to the stand to the first drying cylinder.
• There are no or less cross-tubes between drive side and driver's side necessary, as before; instead supply lines for oil, water and air can now be run directly on the driver's side of the machine cellar; likewise, oil and water drains can be led down directly into the cellar; a decoupling of oil flows in the Filangebchsel deleted.
• The bearing fixtures of the guide roller bearings can be selected solely on the basis of static considerations, without consideration for aspects of the Filzwechsels.

Figur 1

zeigt auf einer Seitenansicht eine Pressenpartie einer Papiermaschine gemäß der Erfindung, mit einer vorgeschalteten Siebpartie und einer nachgeschalteten Trockenpartie.

Figur 2

zeigt ein weiteres Ausführungsbeispiel einer kompakten Pressenpartie einer Papiermaschine gemäß der Erfindung ohne Cantilevermöglichkeit.

Figur 3

zeigt wiederum in Seitenansicht eine Ausführungsform ähnlich jener von Figur 1, jedoch gemäß dem Stande der Technik in Cantilever-Konstruktion.

The invention and the prior art are explained in more detail with reference to the drawings. The following is shown in detail:

FIG. 1

shows a side view of a press section of a paper machine according to the invention, with an upstream wire section and a downstream dryer section.

FIG. 2

shows a further embodiment of a compact press section of a paper machine according to the invention without Cantilevermöglichkeit.

FIG. 3

Figure 11 shows again in side view an embodiment similar to that of Figure 1, but according to the prior art in cantilever construction.

In Figure 1 can be seen a press section 1, which precedes a wire section 2 and a drying section 3 is connected downstream. Decisive here is the structure of the press section. 1

The press section 1 has a plurality of press rollers 4.1, 4.2, 4.4 and 4.6, and a number of guide rollers 5.1 to 5.19.

The press section 1 has a covering. This comprises three permeable felt belts 6.1 to 6.3 and a water-impermeable transfer belt 6.4.

The said elements are all carried by a chair 7. The chair includes, among other things, two supporting structures or supporting walls, one arranged on the driver's side and one on the driving side. On the design it depends according to the invention.

The two mentioned supporting structures are mounted in foundation rails, which in turn are supported by foundation beams 8.

In the upper area and at the end of the press section there is an example of a seam platform 9. This serves as a working platform for producing the seam for the felt belt 6.3.

The said two supporting structures of the chair 7 are each in one piece. Each of the supporting structures may be composed of two or more parts. However, the parts are so rigidly connected to each other, for example by screwing, that the support structure in question has the same rigidity as if it consisted of a single part.

Each support structure extends beyond the accumulation of press rolls and guide rolls in the machine longitudinal direction, and overlaps a part of the wire section 2 and a part of the dryer section 3.

All of the illustrated felt belts 6.1 to 6.3 are provided with a seam. The felt belts are thus initially no endless belts. They are led around for the purpose of drawing around the respective rollers and then connected at their two ends by a seam. The seam platform 9 is just one example of such a work platform. Other work platforms can be provided as needed.

The two supporting structures of the chair 7 are each mounted in a foundation beam 8. There are several sections of such foundation beams 8 which extend over the entire paper machine and abut against each other at separation points. In the area of the bearing of the supporting structures, there is no separation point in the foundation beam 8. In other words, each supporting structure is supported on a complete foundation beam section. In the present case, the foundation beam section 8 shown extends at least from the end of the wire section 2 to the beginning of the dryer section 3 - see the separation points 8.1, 8.2.

The machine shown here works in the usual way:

On the wire section 2, a paper web, not shown here, is produced. The first, upper press felt 6.1 removes the paper web from the screen 2.1, with the help of the guide roller 5.5, which is also a suction roller (so-called pickup roller). The paper web then passes through the first press nip, formed from the press rolls 4.1 and 4.2, together with the two press felts 6.1 and 6.2, between which it is wrapped sandwiched. It then passes to the suction roller. Here, the top felt separates 6.2 and migrates upward, while the paper web comes together with the bottom felt 6.1 to a guide roller 5.16. This is a suction reduction roller. The second top felt 6.3 then guides the paper web to the third press, formed from the press rolls 4.5 and 4.6. Then the paper web is removed at the end of the press section by another pickup roller 5.20 and passes through the dryer section 3. The transfer belt 6.4 is endless. Therefore, the belonging strangulation is cantileverbar. The transfer belt 6.4 may also be a seam felt, i. a felt belt, which is made endless only after drawing. In this case, the stenting would not be cantileverable.

FIG. 2 shows a further embodiment according to the invention of a press section 1 of a paper machine. You can still see the last part of an upstream wire section.

In this case, a paper web, not shown here, is guided from the screen 2.1 to the press section, where it is removed from a first guide roller 5.1, a so-called pickup roller, from the screen 2.1 and transferred to a first press felt 6.1.

The paper web passes through together with the upper press felt 6.1 and another below the paper web extending second press felt 6.4 the first press nip, formed from the press rollers 4.1 and 4.2. The press roll 4.1 is a central press roll, which forms a second press nip together with a further press roll 4.3. After passing through the second of the two press nips mentioned, the paper web follows the press roll 4.3. It then passes through a third press nip, formed from the press rolls 4.3 and 4.4. In this third press nip she encounters a third felt 6.2, which runs above the paper web.

The first press felt 6.1 is guided around a number of further guide rollers 5.2 to 5.7 and the second press felt 6.4 around the guide rollers 5.14 and 5.15. The third press felt 6.2 is guided around guide rollers 5.8 to 5.13.

The paper web is removed from the press roller 4.3 over a free train of a dry felt, not shown here and guided to the dryer section, which is not shown here.

The seam of the two felts 6.1 and 6.2 is produced only after being pulled into the press section.

Those press rolls and guide rolls, which are looped around by the two felt belts 6.1 and 6.2, are located in a frame whose longitudinal members 7 are designed in one piece in the sense of the invention. The guide rollers 5.14 and 5.15, which are looped by the transfer belt 6.4, and the press rollers 4.2 and 4.3 are mounted in a stiffening part which is firmly connected to the foundation. At the end of the press section, the framing parts 7.1 and 7.2 are connected to each other. The framing parts can also be connected to each other at the beginning of the press section.

Figure 3 shows a conventional embodiment of a paper machine. Again, the press section 1, a part of the wire section 2 and a part of the dryer section 3 can be seen. The configuration of the rollers is essentially the same as in the embodiment according to the invention in Figure 1. However, the felt belts 6.1 to 6.3 and Transfer belt 6.4 from the beginning endless belts without seam. For this reason, the press section 1 is constructed here according to the cantilever principle. The stanchion 7 has on both sides - drive side and driver's side - each having a supporting structure, which is composed of several individual parts, namely the components 7.1 to 7.6. These components each have a bending beam associated with lifting device 20. It also recognizes spacers 21, which must be removed before installing the fabric, thus the felt belts 6.1 to 6.4.

The mentioned components are connected to each other. The joints lack the necessary rigidity.

The rigidity of the entire construction is unsatisfactory. There are inadmissible vibrations that affect the paper quality.

LIST OF REFERENCE NUMBERS

1

press section

2

Wire section

2.1

scree

3

drying section

4.1 - 4.6

press rolls

5.1 - 5.19

guide roll

6.1 - 6.4

felts

7

framing

7.1 - 7.6

framing parts

8th

foundation beams

8.1

separation points

9

seam platform

20

Bending beam with lifting device

21

spacers

Claims (6)

1. Machine for producing a web of paper or board;

   1.1 having a pressing section (1), comprising presses (4.1, 4.2; 4.3, 4.4; 4.5, 4.6);

   1.2 having a wire section (2) connected upstream of the pressing section (1) and forming the web;

   1.3 having a drying section (3) connected downstream of the pressing section (1) and drying the web;

   1.4 having framing (7) which, on the drive side and the operator's side, in each case comprises a loadbearing construction extending in the longitudinal direction;

   1.5 having a plurality of rolls (4.1 - 4.6, 5.1 - 5.19) which are mounted in the loadbearing constructions;

   1.6 having felts (6.1 - 6.4) or other fabrics which wrap around the rolls (4.1 - 4.6, 5.1 - 5.19);

   1.7 the felts (6.1 - 6.4) are provided with transverse seams that can be opened and closed;

   1.8 each of the two loadbearing constructions extends in the longitudinal direction of the machine at least over two presses of the pressing section (1) and is in one piece in the longitudinal direction;

   1.9 the two loadbearing constructions are free of spacers (21) that can be removed;

   characterized in that
   the respective loadbearing construction of the framing (7) extends over the entire pressing section (1) as a bridge (4.1, 4.2; 4.3, 4.4; 4.5, 4.6).
2. Machine according to Claim 1, characterized in that the loadbearing constructions are also in one piece in the vertical direction.
3. Machine according to Claim 1 or 2, characterized in that at least one press roll is mounted in accordance with the cantilever principle.
4. Machine according to one of Claims 1 to 3, characterized in that the press has a central press roll, on which at least two pressure nips are formed.
5. Machine according to one of Claims 1 to 4, characterized in that at least one seam platform (9) is located above the framing (7).
6. Machine according to one of Claims 1 to 5, characterized in that foundation beams (8) are provided, which are joined to one another from a plurality of sections in the longitudinal direction of the machine, forming parting lines (8.1, 8.2), and in that the foundation beams (8) are free of disconnecting points (8.1, 8.2) in that region in which they bear loadbearing constructions.

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