Valmet Corporation

Valmet Paper Machinery Inc.

Metso Paper Inc.

Reima Kerttula

Jouko Yli-Kauppila

Jorma Laapotti

Heikki Ilvespaa

Mikko Karvinen

Juhani Pajula

Antti Kuhasalo

Seppo Elijoki

Juha Lipponen

Pekka Kivioja

Juha Kaihovirta

Allan Liedes

Ari Linsuri

Martti Salminen

Timo Nyberg

The invention concerns an integrated paper machine, which comprises, in the running direction of the web, a multi-layer headbox ( ), a gap former ( ), in which there is at least one pre-press (303, 304), a press section ( ), in whcih there is at least one extended-nip press ( ), a pre-dryer section ( ), in which the web (W) is dried by means of a high-capacity dryer unit, a dryer section ( ), in which there is at least one dryer group (R , R , R ) which makes use of single-wire draw, as well as a surface treatment device (P) for the web. Further, the paper machine is provided with a closed web draw at least to the end of the dryer section ( ).

Integrated paper machine

A method for producing surface-treated paper, in particular of fine paper, and a dry end of a paper machine that makes use of the method. A paper web that has been dewatered by pressing is dried in the forward dryer section, in which drying energy is applied to the paper web over the entire length of the forward dryer section asymmetrically in the z-direction from the side of the bottom face of the web. This step is carried out by a number of successive groups with single-wire draw that are open downward. In this manner, shrinkage of the web both in the machine direction and in the cross direction is reduced or at least partially prevented, which shrinkage tends to take place when the dry solids content becomes higher. Paper broke is removed from underneath the drying groups that are open downward substantially by the force of gravity onto the broke conveyor placed underneath. The paper web which has a tendency of curling because of the asymmetric forward-drying is passed to the finishing section where it is finished while it is moistened and/or worked plastically so that the tendencies of curling that arose in the web in the forward drying stage are substantially reduced.

Method for producing surface-treated paper

Dry end of a paper machine

A method and arrangement for evaporation drying of a paper web in which the web is dried in three successive stages I, II and III that are carried out in the direction of progress of the web as follows: in the first stage (I), the web is heated in a short section in the machine direction quickly to a temperature of 55.degree. C. to 85.degree. C. minimizing web breaks of the relatively moist and weak web, after the first stage (I), the main evaporation drying of the web is carried out so that the evaporation efficiency and the rate of increase in the dry solids content of the web are substantially higher than in the first stage or in the final stage (III), and the web temperature does not substantially rise while the drying proceeds, and in the final stage (III), the drying is continued with a decreasing evaporation efficiency and an average rate of increase in the dry solids content of the web in the machine direction which is lower than in the preceding stage (II) but higher than in a conventional cylinder drying with single-wire draw so that the paper quality is controlled at the same time.

Method for optimizing of evaporation drying of paper, runnability, and

A method for calendering a paper web, including the steps of passing the paper web through a calendering nip having a profile formed from a pair of calendering rolls, wherein at least one of the pair of calendering rolls includes a soft exterior face at least in the region of the nip, regulating the profile of the calendering nip to compensate for flaws in the paper web passing through the calendering nip including varying the properties of the soft exterior face locally in a direction transverse to the direction of the passing paper web concurrently with the passing step.

Method for calendering a paper web and a calendar that makes use of the

A method and device for drying a paper web in a dryer section having a number of successive dryer groups with a single-wire draw, and being situated after a press section of the paper machine. Each dryer group includes contact-drying cylinders arranged in a first row and reversing suction cylinders or equivalent suction rolls arranged in a second row, the rows being horizontal, diagonal or vertical rows. The paper web is dried by contact-drying cylinders from the side of its lower face across the entire length of the dryer section. The paper web is passed as a closed draw from one dryer group to the next group, and the paper web is guided, while it runs on the drying wire at the side of the outside curve, by the reversing suction cylinders having a curve radius selected in a range from about 250 mm to about 1000 mm. The paper web is kept in constant contact with the drying wire as it is placed at the side of the outside curve, against the effect of centrifugal forces by a pressure difference which preferably extends over the entire inner circumference of the reversing suction cylinders. In addition to the above, or as an alternative, the paper web is dried from the side of its upper face on a draw or draws of the paper web that is/are free from the wire and/or a flow of drying air is applied to the upper face of the paper web through the drying wire and/or on the draws of the paper web that are free from the wire.

Paper machine and methods for drying a paper web

Dryer sections of a paper machine

Method for producing surface-treated paper and dry end of a paper machine

Methods for drying a paper web

A closed press section in a paper machine including a compact combination of press rolls, some of which define press nips with each other between which the web has a closed draw supported by the face of a fabric. The press section has a center roll in connection with which at least one press nip is formed. A closed loop of a transfer band is passed around the center roll. The web is transferred on an outer face of the transfer band after the last press nip in the compact combination of rolls as a closed and constantly supported draw onto a drying wire in a drying section following after the press section. The transfer band loop is preferably made of a fabric that substantially does not receive water and does not rewet the web. The web-adhesion properties of the outer face of the transfer band are chosen so that, after the last nip, the web follows the transfer band, and so that the web can be transferred as a fully closed draw onto the drying wire. In connection with the loop of the transfer band, means for conditioning/cleaning the band and/or safety devices are provided, by whose means an adequate operation of the transfer band is maintained.

Compact press section in a paper machine

A method and apparatus for lateral alignment of a cross-direction profile control of a web as required in a paper-making process. In the method, a certain cross-direction profile of a dried web, particularly the basis weight profile thereof, to be aligned is gauged. A profile measurement signal thus obtained is passed to a control system of the paper machine which provides a control signal suited to control adjustment devices of the cross-direction profile control provision. The web is provided with at least one marker line whose lateral shift or shifts is/are detected at the measurement point of the cross-direction profile of the dried web, or in the vicinity thereof. The detection of the lateral shift(s) is used to generate a measurement signal thereof which is employed to control the lateral alignment of the web profile adjustment provision. The information obtained from the detected lateral shift(s) then used in the control of the lateral alignment of the consistency profile control provision adapted in conjunction with the paper machine headbox. The marker agent used to make the marker line is injected to the stock at the inlet side of the stock feed channel to the paper machine headbox, most advantageously close to the control valve set of the consistency profile control provision.

Method and apparatus for lateral alignment of the cross-direction

An arrangement in a paper machine dryer section for separating moist dryer section from dry, useful spaces situated underneath the dryer section of the paper machine. Horizontal beams that support the frame of the dryer section of the paper machine are positioned above, or in the upper part of, the space underneath the dryer section. The horizontal beams are supported by vertical beams. The dryer section is surrounded by a hood placed above the floor level of the paper machine hall and which confines the moist spaces of the dryer section in its interior. Underneath the dryer section, a horizontal partition-wall construction is arranged to separate the moist hood spaces of the dryer section from dry, useful spaces situated underneath the moist hood spaces. Conveyor devices for disposing paper broke are arranged above the partition-wall construction. The dry, useful spaces are arranged to be storage spaces and/or installation spaces for one or more other suitable devices of the paper machine.

Arrangement for the space underneath a dryer section of a paper machine

The invention relates to a closed press section in a paper machine and comprises a compact combination of press rolls. Several of the rolls define press nips with each other, between which nips the web has a closed draw supported by the face of a fabric. The press section has a center roll in connection with which a press nip or press nips are provided. A closed loop of a transfer band is passed around the center roll. The web is transferred on an outer face of the transfer band after the last press nip in the compact combination of rolls as a closed and constantly supported draw onto a drying wire in a drying section following after the press section. The transfer band loop is made of a transfer band fabric that substantially does not receive water and does not rewet the web. The web-adhesion properties of the outer face of the transfer band fabric are chosen so that, after the last nip, the web follows the transfer band fabric, and so that the web can be transferred as a fully closed draw onto the drying wire. In connection with the loop of the transfer band fabric, means for conditioning of the band and/or safety devices are provided, by whose means an adequate operation of the transfer band fabric is maintained.

Compact press section with closed draw of the web in a paper machine

An inverted dryer group having a single-wire draw in a multi-cylinder dryer in a paper machine, including steam-heated drying cylinders arranged in a lower row and against which the drying wire of the cylinder group presses a web to be dried into direct contact. Reversing cylinders or rolls of the dryer group are arranged above gaps between the drying cylinders inside a loop of the drying wire. A support wire is placed in contact with the reversing cylinders or rolls over a turning sector of about 60.degree. to about 120.degree.. The support wire is guided by guide rolls arranged in gaps between the reversing cylinders as well as by other necessary rolls. The web is pressed against the drying wire on the turning sector by tension of the support wire.

Growing community of inventors

Muurame, Finland

Reima Kerttula