Metso Paper Inc.

Valmet Corporation

Metso Automation Oy

Jarkko Nurmi

Hans Sundqvist

Jarkko Veijola

Jari Almi

Kari Juppi

Antti Komulainen

Juha Lipponen

Petri Norri

Henrik Pettersson

The narrow-scale moisture profile of a paper web is controlled by profiling nozzles () of a profiling device () which cover part of the width of the web and desired variations of the moisture profile are corrected by the profiling nozzles (). Coating quantity profile of a paper web may also be controlled. The narrow-scale coating quantity profile is controlled by profiling nozzles () of a profiling device () which cover part of the width of the web and desired variations of the coating quantity profile are corrected by the profiling nozzles (). The device () for controlling the moisture profile or the coating quantity profile of a paper web has profiling nozzles () for controlling narrow-scale moisture profile variation, which cover a desired part of the width of the web, to correct desired variations occurring in the profile in the width direction of the web.

Method and device for controlling the moisture or coating quantity profile in a paper web

The invention relates to an air impingement system arranged outside the jacket of an air impingement roll in the drying section of a paper machine or the like for heating and drying a web travelling around the said air impingement roll. The air impingement system comprises a mainly closed hood, which has control means for directing air onto the paper web. From the hood, air is directed by blowing with at least one fan to the blower nozzles and back again into the said hood as a circulation air process, and the system incorporates at least one heating device for heating the air. The air impingement system's hood and its said equipment are used in conjunction with an air impingement roll, which is of the size of approximately 1.5&#x2013;2 m in diameter. The hood of the air impingement roll is at maximum 5 m high, preferably only 1.5&#x2013;2.5 m high.

Impingement system in the drying section of a paper machine or the like

A method of blowing drying gas against a paper web, and an impingement dryer of a paper machine. Drying gas is blown with an impingement dryer comprising several profiling chambers in the cross-direction of a paper machine, the cross-profile of the paper web being controlled with the drying gas blown from the profiling chambers. Each profiling chamber blows drying gas to its own effect range. The impingement dryer further comprises a return air chamber and return air ducts such that drying gas blown against the paper web from the profiling chambers is returned into the return air chamber through the return air ducts in such a way that some of the effect of the drying gas blown from the profiling chamber is at least partly prevented from reaching the effective area of the adjacent profiling chamber.

Method and apparatus for blowing drying gas in a paper machine

A method and device effect controlled uniform temperature drying of a wet web, such as a paper web substantially immediately after formation in a paper machine, without damaging the supporting fabric carrying the web. The web has a central region and first and second border regions. The wet web to be dried is conveyed on a conventional supporting fabric/wire in a first direction generally parallel to the web border regions, and in a hood drying air is blown against the web from the opposite side thereof as the supporting fabric so that the drying air picks up moisture and becomes moistened air. The moistened air is discharged from the volume adjacent the hood, for example is discharged from at least one hood positioned at and encompassing an impingement surface over which the web and supporting fabric pass. Air supplied for blowing against the web is heated to raise its ability to retain moisture. Drying air with a first temperature and first velocity is directed against a central region of the web, and drying air with a second temperature, lower than the first temperature, and second velocity, higher than the first velocity, is directed against the web in the border regions. The hood may be divided into at least one central block and first and second border blocks, corresponding to the central region and first and second border regions of the web. A first plurality of air nozzles may be disposed within the hood central block, and second and third plurality of air nozzles disposed in the hood first and second border blocks, with a different fan and heater supplying air to each of the plurality of air nozzles.

Method and apparatus for controlling the temperature in a paper machine

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Turku, Finland

Jarkko Nurmi