Valmet Corporation

Metso Paper Inc.

Juha Kaihovirta

Antti Kuhasalo

Juha Lipponen

Allan Liedes

Martti Salminen

Jari Vainio

Ismo Koponen

Iimari Rintasalo

Antti Komulainen

Kari Juppi

Pasi Ahonen

Matti Luontama

Jorma Laapotti

Reima Kerttula

Raimo Virta

Heikki Ilvespaa

Pekka Pakarinen

Matti Kurki

Taisto Huhtelin

Nenad Milosavljevic

Pekka Saarikivi

Ville Korhonen

Jaakko Kallioniemi

Harri V&auml;h&auml;talo

An apparatus for a dryer section of a paper or board machine has a drying group (R) and an impingement drying unit () which is placed above and/or below a row (DSR) of drying cylinders (). A drying fabric () supported paper or board web () is conducted past the impingement drying unit () having at least one impingement surface (IP, IP) the side profile of which is straight, changeably curved in its radius of curvature, in the shape of a broken line or a selectable combination of these, and that the impingement surface or a tangent line to the impingement surface or a line passing via the beginning and the end of the impingement surface or an extension of the line forms on the impingement side an angle with a horizontal plane parallel to the machine level, which angle is &#x2266;120&#xb0;, advantageously 120&#xb0;&#x2013;60&#xb0;, most advantageously about 90&#xb0;.

Impingement drying unit and a dryer section

A method and an equipment for regulation of the initial part of the dryer section in a paper machine. Moisture is removed from the paper web in the press section ( ) and the paper web is dried in the dryer section (R). The paper web is dried against heated faces of drying cylinders ( ). The surface temperatures of the first drying cylinders ( ) in the dryer section (R) are measured. The dry solids content/moisture content of the paper web (W) and the temperature of the paper web (W) before said first drying cylinders ( ) are measured. In view of producing the desired running situation, based on the measurement results obtained, the surface temperatures of said first drying cylinders ( ) and/or the dry solids content/moisture content and/or the temperature of the paper web (W) before said first drying cylinders ( ) is/are regulated.

Method and equipment for regulation of the initial part of the dryer section in a paper machine

The invention concerns a method and a device in the dryer section of a paper/board machine. In the dryer section a normal single-wire draw is applied at least partly, in which method the web (W) is passed through the dryer group on support of a drying wire (H). The drying wire (H) presses the web (W) on the drying cylinders (K , K . . . ) against the heated cylinder faces, and on the reversing cylinders or rolls (S , S . . . ) between the drying cylinders ( ) the web (W) remains at the side of the outside curve. There is one integrated device, through which a support suction and/or blowing is produced in order to improve the runability of the web (W) and to keep the web (W) in contact with the face of the wire, and through which same device, additionally, impingement blowing is produced in order to dry the web (W) and/or to control its tendency of curling.

Method and device in the dryer section of a paper/board machine

A dryer section of a paper machine which is provided with at least one intermediate calendering nip and includes several successively arranged wire groups. The dryer section primarily or exclusively has groups with single-wire draw in which heated drying cylinders are arranged in an upper row and reversing suction cylinders or reversing suction rolls are arranged in a lower row below the upper row. The groups with single-wire draw also have a drying wire which runs along a meandering path over the drying cylinders and reversing suction cylinders or rolls so that the reversing suction cylinders remain inside the loop of the drying wire. A calender roll is arranged in opposed relationship to a drying cylinder in one or more of the single-wire draw groups in a sector which the first face of the web is exposed to thereby define a calendering nip therewith.

Dryer sections with intermediate calendering in a paper machine

A method for controlling the curl of paper in which steam treatment and/or moistening of the paper web is/are carried out after the calendering process being performed in the calender. In processes in which calendering is not employed, the curl is controlled in connection with a machine reel-up or in process steps carried out after the machine reel-up. A paper or board machine applying the method includes a headbox, a former, a press, a dryer section and steam boxes, moistening devices, an IR dryer and/or equivalent curl control devices. The steam boxes, moistening devices, IR dryers and/or equivalent curl control devices for the control of the curl are arranged after the calender or, if no calender is employed, in connection with a machine reel-up or a finishing process carried out after the machine reel-up.

Method for controlling the curl of paper and a paper or board machine

A drying unit in a dryer section of a paper or board machine including a drying wire guided in a loop, a large-diameter impingement-drying and/or through-drying cylinder arranged inside the drying-wire loop and smaller diameter smooth-faced heated contact-drying cylinders arranged on top of the large cylinder and/or in the vicinity thereof and at both sides thereof. The impingement-drying and/or through-drying cylinder is placed in a space below the floor level of the paper machine hall and provided with an openable and closable blow hood so that the removal of broke out of connection with the hood takes place substantially by the force of gravity. The central axes of the contact-drying cylinders placed in the vicinity of the large cylinder are placed in the vicinity of, or above, the floor level of the paper machine hall. A curve sector of the paper web on the outer face of the drying wire over the large cylinder greater than about 180.degree..

Drying unit and dryer section that makes use of such units

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 dry end of a paper machine and a method for drying paper in which a paper web to be dried is passed from a press section of the paper machine into a forward dryer section including only single-wire groups with normal single-wire draw. The web is dried from the side of its bottom face in the dryer groups in the forward dryer section. From the forward dryer section, the web is passed into a finishing section in which the web is coated/surface-sized by a coating/surface-sizing device and then dried in an after-dryer by passing through at least one dryer group that applies a normal single-wire draw. Thereafter, the web is calendered and passed to a reeling station. Curling of the web is controlled by the operation or construction of components and/or by assemblies and combinations formed out of these components provided in connection with the forward dryer section and/or the finishing section.

Method for drying paper and a dry end of a paper machine

An after-dryer and method for drying a surface-treated paper web in an after-dryer of a paper machine in which the web is first finished in a finishing section, i.e., surface-sized or coated, by a finishing device and then dried. In the after-dryer, the paper web is dried in at least one dryer group that makes use of single-wire draw and at the same time, the paper web is dried by an impingement-drying equipment arranged in connection with at least one cylinder or roll in the single-wire dryer group.

Method for drying a surface-treated paper web in an after-dryer of a

A dryer section of a paper machine which is provided with at least one intermediate calendering nip and includes several successively arranged wire groups. The dryer section primarily or exclusively has groups with single-wire draw in which heated drying cylinders are arranged in an upper row and reversing suction cylinders or reversing suction rolls are arranged in a lower row below the upper row. The groups with single-wire draw also have a drying wire which runs along a meandering path over the drying cylinders and reversing suction cylinders or rolls so that the reversing suction cylinders remain inside the loop of the drying wire. Two calender rolls are arranged to form the calendering nip through which a paper web to be dried is passed, and thus calendered inside the dryer section, immediately preceding or following or within one or more of the dryer groups of the dryer section.

A dryer section of a paper machine which is provided with at least one intermediate calendering nip and includes several successively arranged wire groups. The dryer section primarily or exclusively has groups with single-wire draw in which heated drying cylinders are arranged in an upper row and reversing suction cylinders or reversing suction rolls are arranged in a lower row below the upper row. The groups with single-wire draw also have a drying wire which runs along a meandering path over the drying cylinders and reversing suction cylinders or rolls so that the reversing suction cylinders remain inside the loop of the drying wire. In one representative embodiment, at a drying cylinder situated inside the group with single-wire draw or in connection with the last drying cylinder in the group, a free space is arranged in which a calender roll is arranged to form the calendering nip together with the drying cylinder in the group with single-wire draw through which a paper web to be dried is passed and, thus, calendered inside the dryer section.

A method and device for enhancing the run of a web in a paper machine in which water is removed from the web by pressing the web in at least one press nip and after pressing, the web is dried in at least one dryer group applying impingement drying. The web is guided along a substantially linear path or by using a large curve radius in the dryer group applying impingement drying. In the drying stage, after the impingement drying, the web is dried in at least one dryer group having normal single-wire draw. The web is passed from the pressing stage to the drying stage as a closed draw and more particularly, from the pressing stage to the area with single-wire draw in the drying stage so that the web is constantly supported against at least one support face.

Method and device for enhancing the run of a paper web in a paper machine

A method for cutting the leader of the web in a paper or board machine in the dryer section of the machine by a jet of pressurized water. The web is placed against the drying wire when it is being cut, and the jet is directed at the web from the free side of the web. The water jet pressure used is from about 40 bar to about 400 bar, preferably from about 100 bar to about 350 bar, which is produced by an ordinary pressure washer.

Dryer section in a paper or board machine including an arrangement for

Method and arrangement for cutting a leader of the web in a paper or

An arrangement for cutting the leader of the web in a paper or board machine in the dryer section of the machine by a jet of pressurized water. The web is placed against the drying wire when it is being cut, and the jet is directed at the web from the free side of the web. The water jet pressure used is from about 40 bar to about 400 bar, preferably from about 100 bar to about 350 bar, which is produced by an ordinary pressure washer.

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Jyvaskyla, Finland

Juha Kaihovirta