Metso Paper Inc.

Reijo Jokinen

Kari Juppi

Antti Komulainen

Matti Kurki

Raimo Virta

Hannu Kokkala

Jorma Laapotti

Samppa J Salminen

Juha Lipponen

Juha Leimu

Markku Lyytinen

Martti Salminen

Seppo Y&ouml;maa

The invention relates to a sealing arrangement () against a moving fabric () in a paper machine or the like. The sealing arrangement includes a stiff sealing element () placed on the fabric's () side on the entire width in connection with a paper sheet () supported by the fabric (). The sealing element has been arranged on a support so that the location of the sealing element with respect to the fabric () can be adjusted nearer to or, correspondingly, further from the fabric. As a sealing element there is at least a single-chambered labyrinth sealing ().

Sealing arrangement against a moving fabric

A method and an apparatus for web threading in a drying section of a paper machine or the like. A leader () and a so called run-down strip are formed by cutting in the web coming to the drying cylinder in the drying section. An underpressure box () is arranged at the opening gap between the drying cylinder () and the drying wire, on that side of the wire which is away from the web, whereby this box can direct against the web an underpressure which is controllable in the machine's cross direction. The underpressure box creates an underpressure region (') between the leader and the underpressure box, the region having an underpressure pat the detachment point, i.e. in the area where the wire is detached from said drying cylinder (), which underpressure is sufficient to detach the leader from said drying cylinder. A protection zone is created between the underpressure region created at the leader and the run-down strip, which protection zone has a barrier () in order to maintain the underpressure pin the underpressure region.

Method and apparatus for web threading in a drying section of a paper machine or similar

A web () running from an opening nip (K) between a cylinder () and a supporting fabric () toward a roll (), is supported by a negative pressure created by a blow box (). In an intensified negative pressure region ('), i.e. close to the disengaging point () between the supporting fabric and the cylinder, the pressure is greater than at a distance from this disengaging point. The negative pressure is controlled according to parameters which act on the runability of the web and which can be varied, such as web velocity, web solid contents, pulp composition, paper or paper board quality, web grammage, a characteristic of the web, such as porosity, traction acting in the web, or web tension, cylinder temperature, and/or the running situation, such as a web break, a threading situation, or a normal run, so the desired runability is maintained between the cylinder and the roll.

Method and apparatus in the drying section of a paper machine or the like

The blowing device comprises a blow box ( ) which is arranged at the opening nip ( ) between the wire and the cylinder and which is provided with at least two nozzles ( ) or the like arranged close to the wire or the like. The first nozzle ( ) is arranged at the opening nip ( ) between the wire and the cylinder, for blowing air away from the gap ( ) between the wire and the blowing device. The second nozzle ( ) is arranged at a distance from said opening nip, in the wire travel direction. The air jets discharged from the nozzles maintain a negative pressure in the space between the blowing device and the wire. In the blowing device, at a short distance from the opening nip, there is further arranged a throttling means ( ) projecting toward the wire, the throttling means dividing the negative pressure space formed between the first nozzle and the second nozzle into an intensified negative pressure region ( &prime;) bordering to the location of the opening nip and into a second lower negative pressure region ( ).

Blowing apparatus in a paper machine or the like

A sealing nozzle is positioned in a blow box used in the drying section of a paper machine. The blow box is mounted on that side of the supporting fabric, which is away from the web at the opening gap between the supporting fabric and the cylinder and at a distance &ldquo;D&rdquo; from the supporting fabric. A passage is formed between the blow box and the supporting fabric, the passage having a negative pressure region having a border with a region outside the negative pressure region. The sealing nozzle is positioned in a wall of the blow box facing the passage at a distance &ldquo;d&rdquo; from the supporting fabric. The sealing nozzle includes: a pivotal sealing member mounted at the border, and a transverse support element, the sealing member pivotal about the transverse support element; and a separate nozzle part having at least one nozzle opening (e. g. a substantially transverse slit) and disposed in the negative pressure region in front of the pivotal sealing member, the separate nozzle part positioned so that the at least one nozzle opening blows air along a surface of the sealing member from the negative pressure region to the region outside the negative pressure region.

Sealing nozzle arranged in a blow box used in the drying section of a paper machine

A blow box used in the drying section of a papermaking machine and a method for sealing a pocket provided with a blow box, and a blow nozzle. The blow box is arranged to eject air away from the space between a wire and the blow box and/or maintain an underpressure zone in this space. In the interface between the desired underpressure zone and an outside volume, the blow box is provided with a sealing element, such as a blow nozzle, protruding towards the wire to a certain distance &ldquo;d&rdquo; seen from the wire, for forming a seal between the underpressure zone and the area remaining outside the underpressure zone. The sealing element is connected to the blow box so that the element may be moved away from the wire to a distance &ldquo;D&rdquo; by a push and/or by an actuator, the distance &ldquo;D&rdquo; being greater than the distance &ldquo;d&rdquo;.

Blow box for the drying section of a papermaking machine, method for sealing a pocket with a blow box in the drying section of a papermaking machine, and arrangement in a papermaking machine

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Raisio, Finland

Reijo Jokinen