FI130435B - Device and method for transferring a strip of a web - Google Patents

Abstract

The invention relates to a device and a method for transferring a strip (1) of a web (2) from a first clothing (14) to a second clothing (13). It is characterized in that the strip (1) is guided between the first (14) and second clothing (13) in a first area (9) whereby the transfer of the strip (1) to the second clothing (13) takes place. This makes automatic web transfer possible with significantly reduced space requirements and lower equipment complexity.

Description

DEVICE AND METHOD FOR TRANSFERRING A STRIP OF A WEB

The invention relates to a method for transferring a strip of a web from a first clothing to a second clothing of a machine designed for producing a fibrous web. The invention also relates to a device for transferring a strip of web in a machine for producing a fibrous web with a first clothing and a second clothing, and with a first zone for the transfer of said strip from the first clothing to the second clothing, wherein in the first zone the strip is guided between the first clothing and the second clothing.

Generally, the web is guided along various clothings in a machine for producing a fibrous web for achieving a desired effect. In terms of the transfer of the web, there is a distinction between an open and a closed draw. A closed draw is characterized by the fact that the web supported by a clothing, such as felt, wire, belt or the like, is directly fed to the next clothing. Due to the continuous support and guidance of the web by the clothing, the closed draw is particularly effective and unproblematic when starting up the machine, i.e. when the web is fed through the machine for the first time. The same issues as during startup are also apparent when feeding the web back in after a web break. In the case of an open draw between two clothings, on the other hand, the web must overcome the open area between clothings without being supported by a clothing.

Accordingly, the start-up or transfer tends to be problematic, since it requires for the web to overcome an open area between the clothings without support and guidance.

Machines for pulp drying process a fibrous web that consists mainly of pulp and typically has a sheet weight of more than 450 g/m? at the production plant. The transition of the web from a first clothing, e.g. the pick-up felt, of a press unit such as a combi-press on to a second clothing, e.g. the felt of a shoe press unit, generally takes place by way of an open draw. Upon startup of the machine or renewed transfer, the web must be manually transferred across the open area from the first clothing to the second clothing.

S For this purpose, a strip is usually cut from the web in the machine direction, for instance

N by ways of a fluid cutting jet directed against the web, which separates it into a strip and

S into the remainder of the web. This strip is manually transferred to the subseguent 2 clothing by a person, i.e. the strip is manually guided inside the machine. Since = 30 manipulation inside the machine in the area of incoming roll nips poses a hazard to life a and limb, technical solutions are reguired to avoid such risks. The machine typically runs & at a speed of 50-200 m/min. After the strip has been successfully transferred, the strip

N is spread out, i.e. the width of the strip as cut from the web is widened, e.g. by moving

N the fluid cutting jet cross machine direction, meaning that the strip encompasses the entire web at the end of this process, after the strip has been transferred, the entire web has thus been transferred.

It should be noted that the strength of a cellulose web increases with increasing proportion of dry content. Accordingly, the pulp web typically has a dry content of <20% prior to mechanical press dewatering, a dry content of typically <60% after mechanical press dewatering, and a dry content of typically >80% after the thermal drying section.

Due to the lower dryness and the associated lower strength of the web in the press area, the transfer task is more difficult than if the web is transferred after thermal drying; this is due to the higher dryness and thus the higher web strength.

Figure 1 of WO 00/31336 shows the typical state of the art of the wet end of a pulp drying machine. This arrangement tends to be insufficient to meet the demands of higher machine speeds. In particular, the transfer of the strip and its spreading across open areas is a highly complicated process that is prone to failure.

The aim of the invention is a closed draw transfer without manual intervention, and an improvement in industrial safety. Further, the device according to the invention is to have minimal space requirements, with a lower overall level of device complexity.

According to the invention, this is achieved by guiding the strip in a first area between the first and the second clothing and transferring the strip from the first clothing to the second clothing, with the first clothing being lifted off after the first area while the strip is guided to a second area with the second clothing and in the second area, the strip is guided between the second clothing and a third clothing. The machine for producing the fibrous web is primarily designed for drying pulp. For the transfer, the strip and the web are jointly passed through at least one press nip of a suction press roll on the first clothing, which is preferably made of felt. At least one further roll presses against the suction press roll, causing mechanical dewatering of the strip and the web to occur in the press nip formed between the suction press roll and the additional roll. The press nip is preferably double felted, i.e. the additional roll pressing against the suction press

N roll is also wrapped in a clothing, which is preferably also made of felt. In the press nip,

N the strip and the web are therefore pressed between two clothings, which are preferably

S made of felt, wherein one roll of the press nip is implemented as a suction press roll. 2 After the press nip, the clothing of the additional roll is lifted off to avoid rewetting. After = 30 guiding the strip alongside the web through at least one press nip on the first clothing, a the strip keeps travelling on the first clothing, with the remaining web following the & clothing of the additional roll to the reject area or to the reject container of the machine.

N The suction press roll must be equipped with at least one suction zone for suctioning of

N the first clothing. Advantageously, the suction press roll after the press nip through which the strip and web are guided together, permits suctioning of the first clothing at least in the region of the strip, which holds the strip, which is firstly guided on the first clothing,

on the suction press roll and secondly minimizing any rewetting after the mechanical pressing. The described arrangement particularly is a combi-press in a machine for pulp drying, with a suction press roll which is wrapped by a first, typically felt, clothing, so that at least one, typically two press nips are arranged against the suction press roll. The press nips are double felted, and the strip is guided on the first clothing after the first press nip for transfer, and the remainder web is fed to the reject area after the first press nip. The strip that is guided on the first clothing is typically transferred to a high-pressure press such as a shoe press after the combi-press. For this purpose, the first clothing and the strip guided thereon are guided into a first area, which is characterized in terms of length in that the first area begins at the point where the first clothing runs onto a second clothing, and ends where the first clothing is lifted from the second clothing, with the strip then continuing to be guided by the second clothing. The strip is thus in contact with the first clothing and the second clothing in the first area, and it is then transferred from the first clothing to the second clothing in the sense of a closed draw in this area.

The first area is further characterized in that the strip does not run through a press nip here, i.e. the only pressure forces acting on the strip in the first area arise as a result of the tension of the first or second clothing and the local curvature in the first area. The strip is guided on the second clothing to a second area, which is characterized in that the second area begins at the point where the second clothing runs onto a third clothing.

The second clothing is typically a felt. The third clothing is also typically a felt, whereby it may also be implemented as an impermeable belt. According to the invention, the second and third clothing form the clothings of the high-pressure press or rather the shoe press.

A preferred embodiment of this method is characterized in that a jet of a pneumatic nozzle acts at least briefly on the first clothing as it is lifted off after the first area, with the jet acting in a cross-machine region of the first clothing, where the strip is guided on

S the first clothing in the first area. According to the invention, the strip is auided by the

S second clothing after the first area, whereby the first clothing is lifted off the second

O clothing at the end of the first area. The jet of the pneumatic nozzle acts on the first 0 30 clothing already shortly after the end of the first area, so that, when seen in a cross-

I machine direction, the jet of the pneumatic nozzle acts in a cross machine region of the a first clothing, where the strip is guided on the first clothing in the first area. The jet of the & pneumatic nozzle supports the transfer of the strip to the second clothing during the

S transfer, i.e. a strip that may incorrectly be dragged along from the first area on the first clothing is detached from the first clothing by the jet, whereby the effect and orientation of the jet cause the strip be removed from the first clothing to be deposited on the second clothing.

A preferred embodiment of the method is characterized in that a jet of a water nozzle acts on the second clothing ahead of the first area, whereby the jet acts in a cross- machine region of the second clothing, where the strip is guided on the second clothing after the first area. The jet of the water nozzle is preferably directed towards the running side of the second clothing, whereby said running side is located opposite to the web side of the clothing, where the fibrous web is located. The water nozzle may for instance be arranged just before the roll that feeds the second clothing to the first area, whereby the roll is designed as a grooved or perforated roll. The jet from the water nozzle saturates the second clothing with water in the effective area of the jet, which increases the smoothness of the second clothing on the web side or rather lowers its permeability.

In accordance with the well-known “glass plate effect’, the strip will tends to follow the second clothing in the first area, and pass from the less “smooth” or rather more permeable first clothing to the more “smooth” or rather less permeable second clothing.

A preferred embodiment of the method is characterized in that the strip and the web are guided together at least with the first clothing through at least one press nip, whereby the strip is suctioned by the first clothing in the area between the press nip and in front of the first area. The machine for producing the fibrous web is especially for drying pulp, whereby the first clothing, which is preferably made of felt, is guided around a suction press roll. At least one further roll presses against the suction press roll.

Advantageously, the suction press roll allows suction of the first clothing at least after the press nip, through which the strip and the web are guided together. This firstly improves the holding of the strip, which is guided on the first clothing, on the suction pressing roll, while secondly minimizing any rewetting after the mechanical pressing.

Another advantageous embodiment of the method is characterized in that at least the strip in the first area is suctioned by the second clothing. In this embodiment, the first area is characterized in that it begins at the point where the first clothing runs onto the o second clothing, and ends where the first clothing is lifted off, with the strip then

O continuing to be guided by the second clothing. Thus, the strip is transferred from the

O first clothing to the second clothing in the first area in the sense of a closed draw. The 0 30 transfer of the strip from the first clothing to the second clothing and the fixing of the strip

I to the second clothing is improved according to the invention in that the second clothing 2 is suctioned at least in the area of the strip. Suctioning of the second clothing primarily & in the area of the strip during its transfer, and thus directing the available vacuum onto

S this area, is particularly advantageous. After the strip has been transferred and spread out, the second clothing may also be suctioned in the area of the entire web, whereby the entire web is fixed, and wrinkling and blistering of the web on the second clothing is prevented.

Another advantageous embodiment of the method is characterized in that at least the strip itself is at least partially suctioned by the second clothing in the section between the first and second area. The first area is characterized in that it begins at the point where the first clothing runs onto the second clothing, and ends where the first clothing 5 is lifted off, with the strip then continuing to be guided by the second clothing. The strip is guided on the second clothing to a second area, whereby the second area is characterized in that it begins at the point where the second clothing runs onto a third clothing. According to the invention, the fixing of the strip on the second clothing in the section between the first and second area is improved in that the second clothing is suctioned at least in the area of the strip. Suctioning of the second clothing primarily in the area of the strip during its transfer, and thus directing the available vacuum onto this area, is particularly advantageous. After the strip has been transferred and spread out, the second clothing may also be suctioned in the area of the entire web, whereby the entire web is fixed, and wrinkling of the web on the second clothing is prevented.

Suctioning in the area between the first area and the second area may be implemented by means of a suction box.

An advantageous embodiment of the method is characterized in that the second clothing is guided over a suction box in the area between the first and the second area, and the second clothing is suctioned by the suction box. The suctioning of the second clothing by the suction box takes place during the transfer of the strip, preferably in the area of the strip, so as to fix the strip on the second clothing. The available vacuum thus is directed to this area. After the strip has been transferred and spread out, the second clothing may also be suctioned by a suction box in the area of the entire web, whereby the entire web is fixed, and wrinkling of the web on the second clothing is prevented.

An advantageous embodiment of the method is characterized in that the second clothing is indirectly suctioned by a suction box in the first area. This may for instance take place

S by guiding the second clothing over a roll, which is implemented as a grooved roll and > suctioning the grooves of the roll directly with the suction box, which is located outside = the roll, and thus the second clothing indirectly. This may for instance also take place by

N 30 guiding the second clothing over a roll designed as a perforated roll and suctioning the = perforated roll directly with the suction box which is located outside the roll, and thus the 3 second clothing indirectly. In the case of the grooved roll, the suction may be directed

O to the area of the strip or else to the entire area by designing the suction box in such a

O way that the grooves are suctioned in the area of the strip or that of the entire web. In the case of the perforated roll, an internal structure such as chambers may be provided so as to direct suction to the area of the strip or to that of the entire web and also the suction box may be designed for zonal suction in this case. The suction box for indirect suctioning of the second clothing can either be designed in such a manner that the suction box only suctions the second clothing indirectly. Otherwise, the suction box can be designed in such a manner that indirect and direct suctioning of the second clothing take place when the second clothing is guided over the suction box. The indirect suctioning of the second clothing has the advantage that a much more compact design is possible, while simultaneous indirect and direct suction of the second clothing means that only the suction box is connected to the vacuum or underpressure system of the machine, and the suction effect may be extended to both suction box and roll. Generally, the roll does not require a direct connection to the vacuum or underpressure system of the machine. The roll according to the invention, implemented as a grooved roll or as a perforated roll suctioned over its entire circumference, can be particularly compact.

Suction rolls connected directly to the vacuum or underpressure system tend to be suctioned axially through the hub, which requires a larger hub diameter and thus a larger bearing design. Such suction rolls that are suctioned through the bearing are complex in terms of mechanical engineering and require a certain minimum diameter for technical reasons. The roll according to the invention, designed as a grooved roll or as a perforated roll suctioned over its entire circumference, may be implemented with smaller minimum diameters.

Another advantageous embodiment of the method is characterized in that the strip, having been guided through the second area, is cut from the web and spread out; after spreading out, the entire web is then guided across the second area. The guiding of the strip through the second area entails the successful transfer of the strip, and the width of the strip cut from the web may thus be increased continuously, for instance by moving the fluid cutting jet that cuts the strip from the web cross machine direction. By moving the fluid cutting jet cross machine direction, the width of the strip may be increased until the strip covers the entire web. Accordingly, after the strip has been transferred and o spread out, the entire web is transferred to the second area. The spreading out process

O is then complete. In the case described, the transfer of the strip exiting a combination

O press and guided on a first clothing, preferably a felt, to a second clothing, also 0 30 preferably a felt, has been completed, whereby the strip is guided on the second clothing

I into a second area and further into a high pressure press, typically a shoe press, a together with a third clothing.

S

LO An advantageous embodiment of the method is characterized in that the length of the

O first area is reduced after spreading out. The first area and in particular its length are characterized in that the first area begins at the point where the first clothing runs onto the second clothing and ends where the first clothing is subsequently lifted off the second clothing. During the transfer, the strip continues to be guided by the second clothing. In the first area, the strip is thus transferred from the first clothing to the second clothing. The presence of the first area for transfer of the strip means that a length of the first area greater than zero and thus a closed guidance of the strip between the press nip, which the strip and the first clothing are guided through together, and the beginning of the second region. Accordingly, the strip is always in contact with or rather guided by a clothing between the press nip and the beginning of the second area. The transfer of the strip takes place closedly as a closed draw. After transfer of the strip to the second area and spreading out, the web is guided openly for a short section or rather the web passes into a short area between first and second clothing as an open draw. In order to implement a closed draw followed by an open draw after spreading out, the first clothing

Is guided across a subseguent roll after the first area, whereby the length of the first area if adjustable via the position of the subsequent roll. The wrapping of the grooved roll or the perforated roll suctioned over its entire circumference by the first clothing may be adjusted via the position of the subsequent roll. According to the invention, it is advantageous to realize a longer first area for transfer of the strip so as to achieve better fixation of the strip on the second clothing. For this purpose, the positioning of the subsequent roll is adjusted to ensure more extensive wrapping of the grooved roll or the perforated roll suctioned over its entire circumference by the first clothing. After spreading out, the positioning of the subsequent roll may be adjusted to shorter wrapping or alternatively no wrapping of the grooved roll or the perforated roll suctioned over its entire circumference by the first clothing. In case of no wrapping, a relative speed difference is feasible between the first and second clothing in the short open area, the open draw, with the speed of the first clothing being less than or equal to the speed of the second clothing when the pulp drying machine is in operation. Less extensive wrapping is advantageous with regard to any rewetting of the web by the first clothing in the first area. Minimal rewetting by the first clothing is achieved by minimizing the length of the first area, whereby a certain length is advantageous for transfer of the strip from

N the first clothing to the second clothing.

N x An advantageous embodiment of the method is characterized in that the web consists © 30 predominantly of cellulose and has a sheet weight of more than 450 g/m?. The invention

I is particularly suited for transferring a strip from the combination press into a high- a pressure press, in particular a shoe press, of a machine for drying cellulose. According & to the invention, the sheet weight of the strip to be transferred in this type of machine

S must be greater than 450 g/m?. However, it cannot be ruled out that the process of transferring the strip with a sheet weight <450 g/m? takes place on a machine for pulp drying, e.g. so as to minimize the proportion of rejects from the transfer. However, this does not contradict the applicability of the invention for transferring strips on a pulp drying machine in any way.

Another advantageous embodiment of the method is characterized in that the strip is cut across the entire width of the strip cross machine direction before the first area. On the one hand, a fluid cutting jet is used to cut a strip from the web in the machine direction separating the web into the strip and a remainder web. According to the invention, the strip is now cut transversely across the entire width of the strip in front of the first area, advantageously prior to the press nip. This may be performed by a cutting jet from a nozzle, with the cutting jet acting cross machine direction across the entire width of the strip. This cutting of the strip over its entire width interrupts the endless strip, whereby the strip is transferred to the second clothing upstream of the cut.

The invention also relates to a device for transfer of a strip of a web in a machine for producing a fibrous web, characterized in that the second clothing is guided over a grooved roll or perforated roll in the first area, and the second clothing is suctioned indirectly via a suction box in the first area within at least in the area of the strip, by direct suctioning of the grooves or perforations of the roll by the suction box. By implementing the roll as a grooved or perforated roll, the roll may be vacuumed via a suction box located outside the roll, the roll can be very compact implemantation.

An equally advantageous embodiment of the device is characterized in that the strip and the web are guided together with at least the first clothing through at least one press nip, whereby one roll is designed as a suction press roll, and said suction press roll forms part of the press nip, with the first clothing wrapping around the suction press roll, which is equipped with at least one suction zone for suctioning the first clothing in the area after the press nip, and whereby the second clothing is guided across a suction box after the first area, with the second clothing can be suctioned via the suction box at least in

S the area of the strip. During the transfer of the strip, suctioning of the first clothing after

N the press nip at least in the area of the strip via the suction press roll is advantageous.

S This allows the strip to be fixed on the first clothing after the press nip. Suctioning of the 2 first clothing after the press nip is also advantageous with regard to rewetting of the strip = 30 or the web. After the first area, suctioning of the second clothing, at least in the area of a the strip, improves fixation of the strip on the second clothing, whereby the second & clothing is guided across a suction box and suctioned by it. After spreading out of the

N strip, it is advantageous for both the suction press roll and the suction box to suction the

N entire width of the web.

A further advantageous embodiment of the device is characterized in that the first clothing after the first area is guided over a subsequent roll, with the length of the first area being directly adjustable by positioning of the subsequent roll, and a jet of a pneumatic nozzle is directed on the first clothing, which is lifted off after the first area, in an area of the first clothing, introduced in a cross machine direction, where the strip is guided in the first area on the first clothing. The transfer of the strip from the first clothing to the second clothing takes place in a closed manner by means of a closed draw, with the subsequent roll being positioned such that the first clothing at least partially wraps around the second clothing. After spreading out, the length of the first area is minimized or left open. In case of a minimal first area, the subsequent roll is positioned so as to ensure that the first clothing at least briefly wraps around or is in contact with the second clothing, thereby realizing a closed draw. If the first area is left open, the subsequent roll is positioned so as to ensure that the distance between the first clothing and the second clothing is minimized, whereby the web changes from the first clothing to the second clothing in an area of a short open draw. The pneumatic jet directed at the first clothing shortly after the first area ensures that a strip erroneously travelling along with the first clothing after the first area is lifted off the first clothing and deposited on the second clothing.

The invention is described further with reference to exemplary drawings below.

Fig. 1 shows a machine for producing a fibrous web in accordance with prior art.

Fig. 2 shows the device according to the invention for transferring a strip, with the strip being guided in a closed manner.

Fig. 3 shows the device according to the invention for transfer of a strip after transferring and spreading out of the strip with a short open draw of the web.

N 25 Fig. 4 shows the suction box according to the invention for the direct suctioning of a roll > and the indirect suctioning of the second clothing. <Q

Q Fig. 1 shows an overview of the sheet formation unit and the press section of a machine = 10 for producing a fibrous web in accordance with prior art. The sheet forming unit for a forming the web 2 is designed as a twin-wire dewatering unit with a press section

D 30 eguipped with a first press unit 6 and a subseguent press unit 7. Further subseguent

S units of the machine are not shown. Corresponding to the open draw between the first

N press unit 6 and the subseguent press unit 7, a strip 1 of the web 2 is first transferred and then spread out to the machine width. Also shown is an endless clothing 14 of the first press unit 6 and the endless clothing 13 and 15 of the subsequent press unit 7.

According to Fig. 1, the running direction of the web 2 is from left to right.

Fig. 2 shows the device according to the invention and illustrates the method for transferring the strip 1. The strip 1 in the first press unit 6 is cut from the web 2 in front of a press nip 5 and the strip 1 and the remainder web 2 are passed through the press nip 5 on the first clothing 14. The remainder web 2 is removed from the first clothing 14 after the press nip 5 and moved into a reject area or a reject container (not shown). The strip 1 is guided further around the suction press roll 4 on the first clothing 14, whereby the suction press roll 4 allows at least after the press nip 5 suctioning of the first clothing 14 at least in the region of the strip 1. The first clothing 14 and the strip 1 are joined with a second clothing 13 in a first area 9, whereby the second clothing 13 is guided over a roll 11, which is implemented as a grooved 11 or perforated roll 11. The roll 11 allows suctioning of the second clothing 13 at least in the area of the strip 1. At the end of the first area 9, the first clothing 14 is lifted off, with the strip 1 continues running on the second clothing 13. The length of the first area 9, or rather the point where the first clothing 14 is lifted from the second clothing 13, is determined by the position of a roll 18. In Figure 2, the roll 18 is shown in the position for transferring the strip 1 as a continuous circle and the position of the roll 18 after the transfer and spreading is shown as a dashed circle. During the transfer, the jet from the pneumatic nozzle 8 acts on the first clothing, at least in the area shortly after the first area 9 introducing in a cross machine region of the first clothing 14, where the strip 1 is guided on the first clothing 14 in the first area. Between the first 9 and second area 19, the clothing is guided over a suction box 12, whereby the second clothing 13 is suctioned at least in the area of the strip via the suction box 12. The suction box 12 further allows indirect suctioning of the second clothing 13 in the first area 9, whereby suction box 12 suctioning the roll 11, which is implemented as a grooved 11 or perforated roll 11, directly over its o circumference. The second area 19 is characterized by the placement of a third clothing

O 15 onto the second clothing 13 which is guiding the strip 1. A jet of a water nozzle 16

O may act on the second clothing 13, with the jet acting across machine area of the second 0 30 clothing 13, where strip 1 is guided on the second clothing 13 after the first area 9. The

T jet from the water nozzle 16 can saturate the second fabric in the effective area of the a jet, which increases the smoothness of the second clothing 13 on the web side or rather & lowers its permeability. The transfer of the strip 1 is completed by successful guidance

S of the strip 1 through the second area 19, with the strip subsequently being spread out and the entire web 2 having been transferred.

Fig. 3 shows the device according to the invention after transfer of the strip 1 and the spreading out with a short open draw of the web 2. After spreading out, the strip 1 takes on the entire width of the web 2, whereby the web 2 is guided through the press nip 5, and the entire web 2 is guided over the suction roll 4 on the first clothing 14. After the press nip 5, the web 2 may be suctioned through the first clothing 14 by way of the suction roll 4. The roller 18 is now in the operating position, characterized in that the first area 9 formed during the transfer of the strip 1, which is created by the second clothing 13 being wrapped by the first clothing 14, is minimized (not shown) or disbanded (as shown in Fig.3). A minimized first area 9 arises when the first clothing 14 and the second clothing 13 remain in contact and the web 2 is thus transferred from the first clothing 14 to the second clothing 13, which results in a closed draw. Once the first area 9 is disbanded, the first clothing 14 and the second clothing 13 are spaced apart, i.e. not in contact, and the web 2 is transferred openly from the first clothing 14 to the second clothing 13, thus realizing an open draw (as shown in Fig. 3). The advantage of an open draw is particularly the possibility of realizing different speeds between the first clothing 14 and the second clothing 13, whereby the speed of the clothings remains the same or increases in the machine direction according to the invention. After spreading out, the second clothing 13 either has the same or a higher speed than the first clothing 14. With increasing speed in the machine direction, a longitudinal stretching of the web may be compensated, with the result that blistering or streaking can be prevented. According to the invention, a water nozzle 16 may be used to support the transfer of the strip 1, whereby the water nozzle 16 is not anymore active after spreading out.

Fig. 4 shows the roll 11, which may be implemented as a grooved 11 or perforated roll 11, with the roll 11 being suctioned directly over its circumference via the suction box 12. The grooving 17 of the roll 11 or alternatively the perforated suction width 17 of the roll 11 is shown in Fig. 4. During the transfer of the strip 1, suctioning of the second clothing 13 is at least advantageous in the area of the strip 1. For this purpose, the suction box 12 may be designed with a separate edge zone 18 in order to concentrate o the suctioning on the area of the strip 1 during the transfer thereof. After spreading out,

O suctioning over the entire width of the web 2 may be advantageous in order to improve

O the fixation of the web 2 on the second clothing 13 and to prevent blistering and 0 30 streaking. = The present invention thus offers advantages over conventional transfer devices. In 3 addition to automatic web transfer without manual contact with the web and the

O associated improvement in industrial safety, the invention permits automatic transfer

O with a very small space reguirement and reduced overall mechanical engineering complexity.

Claims (14)

Claims

1. A method for transferring a strip (1) of a web (2) from a first clothing (14) to a second clothing (13) of a machine (10) for producing a fibrous web, characterized in that the strip (1) is guided between the first clothing (14) and the second clothing (13) within a first area (9), where the strip (1) is transferred by a closed draw from the first clothing (14) to the second clothing (13) in the first area (9), with the first clothing (14) lifted off at the end of the first area (9) and the strip (1) continues with the second clothing (13), whereby the strip (1) is guided to a second area (19) on the second clothing (13), where the strip (1) is guided between the second clothing (13) and a third clothing (15) where after the transfer of the strip (1) to the second area (19) and after spreading out the strip (1) and transferring the entire web (2) the length of the first area (9) is reduced until the first clothing (14) and the second clothing (13) are spaced apart realizing an open draw transfer of the web (2) from the first clothing (14) to the second clothing (13).

2.A method according to claim 1, characterized in that a jet of a pneumatic nozzle (8) acts at least briefly on the first clothing (14) once it is lifted off after the first area (9), with the jet acting at cross machine area of the first clothing (14), where the strip is guided on the first clothing (14) in the first area (9).

3. A method according to claim 1, characterized in that the strip (1) and the web (2) are guided through at least one press nip (5) together with at least the first clothing (14), whereby the strip (1) is suctioned in the area between the press nip (5) and before the first area (9) through the first clothing (14).

4. A method according to claim 1, characterized in that at least the strip (1) in the first area (9) is suctioned through the second clothing (13). N

N 5. A method according to claim 1, characterized in that at least the strip (1) is at least S partially suctioned in the section between the first (9) and second area (19) through the S 30 second clothing (13). j

N 6. A method according to claim 5, characterized in that the second clothing (13) is guided O in the area between the first area (9) and the second area (19) over a suction box (12), and O the second clothing (13) is suctioned by the suction box (12).

7. A method according to claim 4, characterized in that the second clothing (13) in the first area (9) is suctioned indirectly through a suction box (12).

8. A method according to claim 7, characterized in that the second clothing (13) is guided over a roll (11) in the first area (9), whereby the roll (11) is a grooved (11) or perforated roll (11) and the suction box (12) is directly suctioning the grooves or perforations of the roll (11), thereby suctioning the second clothing (13) indirectly via the suction box (12).

9. A method according to claim 1, characterized in that after guidance of the strip (1) through the second area (19), the strip (1) cut out of the web (2) is spread out, and the entire web will be passed through the second area (19).

10. A method according to claim 1, characterized in that the web (2) consists predominantly of cellulose with a sheet weight in excess of 450 g/m?.

11. A method according to claim 1, characterized in that the strip (1) is cut across its entire width ahead of the first area (9) in cross machine direction.

12. A device for performing the method of one of the claims 1 to 11, characterized in that that the second clothing (13) is guided over a roll (11) in the first area (9), whereby said roll (11) is a grooved or perforated roll (11), and the second clothing (13) is indirectly suctionable in the first area (9) at least in the area of the strip (1) via a suction box (12) by directly suctioning the grooves of the roll (11) or by directly suctioning perforations of the roll (11) by the suction box (12).

13. A device according to claim 12, characterized in that the strip (1) and the web (2) are guided through at least one press nip (5) together with at least the first clothing (14) one — roll (4) as part of the press nip (5) being a suction press roll (4), whereby the first clothing (14) wraps around the suction pressing roll (4), and the suction press roll (4) having with at N least one suctioning zone for suctioning the first clothing (14) in the area after the press nip a (5), and that the second clothing (13) is guided over a suction box (12) after the first area x (9), whereby the second clothing (13) is suctionable via the suction box (12) at least in the © 30 area of the strip (1). = a

14. A device according to claim 12, characterized in that the first clothing (14) is guided & over a subsequent roll (18) after the first area (9), whereby the length of the first region (9) N is directly adjustable by adjusting the position of the roll (18) and wherein a jet of a N 35 pneumatic nozzle (8) is directed onto the first clothing (14) where the strip is lifted off after the first area (9), and the jet is introduced in the cross machine area at the first clothing (14), where the strip (1) is guided in the first area (9) on the first clothing (14).