CN108368678B

CN108368678B - Apparatus and method for transferring a web inside a paper machine

Info

Publication number: CN108368678B
Application number: CN201680070954.7A
Authority: CN
Inventors: 弗兰克-约亨·奥特; 理查德·霍恩; 瓦伦丁·索夫卡; 贝恩德-乌韦·施特尔纳
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2015-12-04
Filing date: 2016-11-07
Publication date: 2020-03-27
Anticipated expiration: 2036-11-07
Also published as: EP3384086B1; CN108368678A; WO2017092969A1; EP3384086A1; DE102015224280A1

Abstract

The invention relates to a device and a method for transferring a web from a first treatment unit (11) having a first, encircling clothing (8) to a second treatment unit (13) having a second, encircling clothing (9) in the interior of a paper or board machine, the web (2) resting on the first clothing in a first web travel path (15), the web (2) being transferred onto the second clothing and guided in a second web travel path (17), wherein a deflecting roller (7) designed as a suction roller is provided, which is suitable for lifting the web (2) off the first clothing (8) and deflecting it in the direction of the second clothing (9). For reliable design transfer, provision is made for: a web separation element (4) is arranged in the web running direction after a turning roll (7) configured as a suction roll.

Description

Apparatus and method for transferring a web inside a paper machine

Technical Field

The invention relates to a device for transferring a web from a first treatment unit having a first, revolving screen to a second treatment unit having a second, revolving screen within a paper or board machine, the web resting on the first screen in a first web travel path, the web being transferred to the second screen and guided in the second web travel path, wherein a deflecting roller configured as a suction roller is provided, which is suitable for lifting the web from the first screen and deflecting the web in the direction of the second screen.

The invention further relates to a method for transferring a web from a first treatment unit having a first, revolving screen to a second treatment unit having a second, revolving screen within a paper or board machine, the web resting on the first screen in a first web travel path, the web being transferred to the second screen and guided in a second web travel path, wherein a deflecting roller designed as a suction roller lifts the web from the first screen and deflects it in the direction of the second screen.

Background

These transfer points in a paper or board machine are well known to the person skilled in the art. These transfer points can be located both in the wet area and in the drying area, i.e. for example in the press, screen or drying unit. Turning rolls constructed as suction rolls have been the state of the art for many years. The term "stretched web" is understood to mean a dewatering, felt or drying web. In addition, within the scope of the present application, all paper machine fabrics (known as fabrics in english) and all types of supporting belts should be assigned to the clothing.

Exemplary of this, referred to as prior art, is DE 19636791 a1, whose fig. 1 is again accommodated in fig. 3 within the present application, in order to better illustrate the prior art. In this fig. 3, the pressing member is designated as a whole by the numeral 10. The paper web 64 is lifted from the screen cloth 14 of the screen cloth part 12 arranged upstream, which screen cloth is guided via the screen

cloth guide rollers

16, 18, by a deflecting roller or pickup roller 32 with suction support and reaches the press nip 34 on the upper felt 30. The upper felt 30 is guided upwardly away by the felt guide rollers 40 after exiting the press nip 34.

In addition, a lower felt 42 is guided through the press nip 34, which lower felt is guided via felt

guide rollers

44, 46 and 48. After the nip 34, the paper web 64 is transferred by means of the suction roll 60 onto the drying wire 58 and conveyed in the direction of the arrow 62 into the drying section arranged behind.

It is to be understood that depending on the design of the paper machine, a plurality of press nips can also be provided one after the other.

After the press nip 34 and after the suction roll 60 carrying the paper web 64 onto the drying wire 58, seen in the web running direction, a device, which is designated as a whole by the numeral 20, is arranged on the inner side of the lower felt 42. The apparatus 20 comprises a blowing device in the form of a blow box 22, which is arranged in front of the following felt guide roll 46 and has a slit-like blow opening 24, via which compressed air can be blown through the lower felt 42 in order to cause the paper web residue to be lifted from the lower felt 42 at the start of the paper machine or in the event of a web break and to be conducted out in the direction of the arrow 28 into a pulper 54 arranged below, as indicated by the web discharge section marked with the numeral 56.

The suction roll 60 is pivotable and can thus be pivoted to the lower felt 42 in order to divert the paper web onto the drying wire 58 with suction support.

During a production run, the suction roll 60 is thus in a position pivoted on the lower felt 42, so that the paper web is transferred directly onto the drying wire 58.

It has been found, however, that even though the device of DE 19636791 a1 works well, it sometimes happens that the web does not always break as specified or is separated by means of a blowing device when being changed over to a drying wire (referred to as "second wire-stretch" in this application). This means that the web discharge section provided, which should have been displaced into the pulper on the first web path of travel, is again drawn upwards into the second web path of travel together and causes problems in this. Paper waste or larger thickenings may form, which leads to web breaks.

Disclosure of Invention

The task of the invention is that: so that a more functionally reliable transfer of the web from the first web travel path to the second web travel path is achieved.

In the context of the apparatus mentioned, this task is solved in that a web separation element is arranged in the web travel direction after the turning roll configured as a suction roll.

The web separation element, when activating the deflecting roller configured as a suction roller, causes, for example, a web which has been pulled up again on the first web travel path in the direction of the pulper to be separated and not carried over to the second web travel path. It has been found that the web can be moved during the change from the first to the second web travel path in such a way that the web run-off is guided through the separating element and the web is forced to separate there. This results in only the very short end of the beginning of the new web being switched, if necessary folded, to the second web travel path. However, this very short fold does not have a negative effect on the transport function.

In order to keep the maximum web bending length as small as possible, it is advantageous if the separating element is arranged between 200mm and 600mm after the suction roll in the web travel direction of the first web travel path.

A compromise is thus found which on the one hand provides sufficient space for pivoting the suction roll and on the other hand remains as short as possible for the separated web end or the new web start of the second web travel path.

Advantageously, the separating element is formed by a blade.

The blade occupies a minimum space here and is a particularly inexpensive component. After being placed in the correct place, the blade does not even need to be moved when cutting the web. The blades can be fitted firmly because the web is guided by the blades and cut during the turning process. The blade can have a smooth or serrated cutting edge. It has been shown in many cases that curved or inclined cutting edges can also be of interest, since a diverted web whose width can be up to 10 m wide is first cut in this way at a first point and the cutting can then continue to the edge without problems.

Preferably, the distance between the blade and the first screen is 15mm to 40 mm. In the run phase of papermaking, where the web is guided via the first web travel path, for example into the pulper, due to a take-off or web break, there is no risk of the web becoming entangled, since its spacing from the blade is sufficiently large. In this case, it is advantageously provided that the blades are arranged perpendicular to the screen, so that no regions are formed in which paper dust can accumulate. Furthermore, the blade is substantially perpendicular to the web even when cutting.

It is particularly advantageous if the holder on which the blade is fitted comprises a splash protection wall.

The holder of the blade thus assumes a second function and prevents splashing from the moist web or the moist felt onto other components of the paper machine.

Preferably, the blade is fitted on the holder in a replaceable manner.

Each cutting edge of the blade eventually wears. To simplify the exchange of the blade, the blade is mounted on the holder in an easily detachable manner. The connecting element should be as accessible as possible from the edge of the paper machine in order to make the replacement as simple as possible for personnel.

In terms of method, this object is achieved with the method according to the invention for transferring a web from a first processing unit with a circulating first fabric to a second processing unit with a circulating second fabric inside a paper or board machine by: the turning is performed in such a way that the web is brought into contact with and separated by the separating element.

The web travelling on the first web travel path is thus changed over to the second web travel path by means of a turn roll configured as a suction roll. The web section that has advanced on the first web travel path, for example in the direction of the pulper, is again pulled high and, by its contact with the separating element, is subjected to cutting preferably over the entire web width. This inventive approach is surprisingly simple.

As already explained in the device according to the invention for transferring a web from a first processing unit with a circulating first clothing to a second processing unit with a circulating second clothing in the interior of a paper or board machine, it is sufficient if the separating element is preferably constructed by a simple, preferably stationary blade in the method.

In the method, the web is preferably guided on the first paper web travel path when it has to be led out downwards into the pulper. This is the case when the web has to be introduced only and has been cut, or when the web breaks before the transfer point. Thereby, the web following at speeds of up to 2000 m/min does not accumulate in the paper machine unit and does not have to be removed again in a cumbersome manner.

During the production process of the paper machine unit, the web is usually diverted upwards and guided further via a second web travel path.

Drawings

The invention will be explained in more detail below with the aid of embodiments and with reference to the drawings. Wherein:

fig. 1 shows a schematic side view of an apparatus for transferring a web according to the invention;

fig. 2a and 2b show two schematic side views of an apparatus for transferring a web, the purpose of which is to show what happens when there are no characterizing features according to the invention;

fig. 3 shows a prior art diagram for the described part of the prior art.

Detailed Description

Fig. 1, 2a and 2b use the same reference numerals for the same components. However, fig. 1, i.e. a diagrammatic representation of a transfer apparatus according to the invention, can be explained more easily when first the present situation of such a transfer apparatus without features that are important for the invention is explained in connection with fig. 2a and 2 b.

On the right-hand side in fig. 2a, the first stretching wire 8 guided by the two guide rollers 21 is seen. In this case, it refers to a felt, for example, which surrounds the felt guide roller 21. The web 2 lying on the clothing 8 is moved from a first processing unit 13, for example a press, on a first web travel path 15 and is fed downwards to a pulper, not shown. This web travel path 15 is provided for the web 2 when, for example, a fault occurs in the first processing unit 13, or when the web 2 is reintroduced and must first have been cut before being conveyed.

In order to divert and discharge the web onto a stretching wire 9, for example a dryer wire, a deflecting roller 7 configured as a suction roller is provided.

Fig. 2b now shows that a deflecting roller 7, which is designed as a suction roller, can be pivoted in rotation at web speed to the web 2 supported by the first clothing. As soon as the negative pressure is activated, the web 2 is deflected in the direction of the second clothing 9. It is planned here that the web breaks at that time, so that a new web start starts the run of the second web travel path 17. However, this does not always operate as specified. In contrast, the situation shown in fig. 2b appears to be that the web does not completely break, but that the part of the web that has gone in the direction of the pulper is again lifted and carried on the second web travel path in the direction of the second treatment unit, for example a drying element. This may lead to serious failures.

The solution according to the invention is thus provided as shown in fig. 1. In the web travel direction of the first web travel path 15, a web separation element 4 is arranged immediately after the turning roll 7 configured as a suction roll. In this embodiment, it refers to a blade 4' of the same width as the web, with the cutting edge facing the first clothing 8. The blades 4' are arranged perpendicular to the screen at a distance of 15mm to 40mm from the screen. A spacing of 200mm to 600mm after the deflecting roller 7, which is designed as a suction roller, has proven to be advantageous for separating the elements 4. After the blades, the web 2 travels into a pulper 19 after a short support by the stretching wire 8.

If the web 2 is now dispatched onto the second web travel path 17 by means of the deflecting roller 7 configured as a suction roller as already explained in the description of fig. 2a and 2b, the web is in direct contact with the blade 4' and is separated.

The blade 4' is detachably mounted on the holder 6 in order to be able to easily replace it when worn. In this embodiment, however, the holder also assumes the function of splash protection and is configured as a splash wall 6'. Thus, other machine parts are protected from moisture from the web 2 or from the first clothing 8.

List of reference numerals

Apparatus for transferring a web

2 Web Material

3 returning web

4 Web separating element

4' blade

5 web discharge section

6 holding member

6' splash wall

7 deflecting roller designed as a suction roller

8 first stretching net and felt

9 second stretching and drying net

11 first processing unit (e.g. extrusion member)

13 second treatment unit (e.g. drying unit)

15 first web travel path

17 second web travel path

19 pulper

21 guide roller

Prior art in FIG. 3 according to DE 19636791A 1

10 paper machine units, e.g. press sections

12 Screen member

14 net

16 screen mesh guide roller

18 screen guide roller

20 device

22 blast box

24 blowing opening

30 felt

32 deflecting or pick-up roller

34 extrusion gap

40 felt guide roller

42 lower felt (corresponding to the first stretching net 8)

44 felt guide roller

46 felt guide roller

48 felt guide roller

Pulper 54 (corresponding to pulper 19)

56 Web discharge section

58 drying net (corresponding to the second stretching net 9)

60 suction roll (corresponding to the deflecting roll 7 configured as a suction roll)

62 direction

64 paper web (corresponding to web 2)

Claims

1. Device for transferring a web inside a paper or board machine from a first processing unit (11) with a circulating first clothing (8) against a second processing unit (13) with a circulating second clothing (9), the web (2) resting on the first clothing in a first web travel path (15), the web (2) being transferred onto the second clothing and guided in a second web travel path (17),

wherein a deflecting roller (7) is provided, which is designed as a suction roller and is suitable for lifting the web (2) from the first clothing (8) and deflecting it in the direction of the second clothing (9),

it is characterized in that the preparation method is characterized in that,

a web separation element (4) is arranged in the web running direction after the turning roll (7) configured as a suction roll, which is configured such that the web comes into contact with and is separated by the separation element by turning.

2. An apparatus according to claim 1, characterized in that a separating element (4) is arranged between 200mm and 600mm behind the turning roll (7) configured as a suction roll in the web travelling direction of the first web travelling path (15).

3. The device according to claim 1 or 2, characterized in that the separating element (4) is formed by a blade (4').

4. A device according to claim 3, characterized in that the blade (4') is spaced from the first clothing (8) by 15 to 40 mm.

5. Device according to claim 3, characterized in that the blade is fitted on a holder (6) comprising a splashproof protection wall (6').

6. Device according to claim 3, characterized in that the blade (4') is fitted in a replaceable manner on the holder (6).

7. Method for transferring a web (2) from a first processing unit (11) having a circulating first clothing (8) to a second processing unit (13) having a circulating second clothing (9) inside a paper or board machine, the web (2) resting on the first clothing in a first web travel path (15), the web (2) being transferred to the second clothing and guided in a second web travel path (17),

wherein a deflecting roller (7) configured as a suction roller lifts the web (2) from the first clothing (8) and deflects it in the direction of the second clothing (9),

it is characterized in that the preparation method is characterized in that,

the web (2) is brought into contact with and separated by a separating element (4) by turning.

8. A method according to claim 7, characterized in that the separating element (4) cuts the web (2) across the entire width.

9. Method according to claim 7 or 8, characterized in that the separating element (4) is formed by a blade (4').

10. A method according to claim 7 or 8, characterised in that the first web travel path (15) is used by the web during the start-up process of a paper machine unit or web breaks.

11. A method according to claim 7 or 8, characterised in that the second web travel path (17) is used by the web during the production process of a paper machine unit.