Valmet Corporation

Ari Linsuri

Jyrki Huovila

Jyrki Jaakkola

Lauri Verkasalo

Michael H Odell

Antti Poikolainen

Petri Nyberg

Erkki Partanen

Reima Kerttula

Pekka Kivioja

Heikki Ilvespaa

Timo Nyberg

Michaell Odell

Pasi Turpeinen

Heikki Ilvesp Aa

A stock feed system for a multi-layer headbox and a method in the operation of a multi-layer headbox in which into each inlet header of the multi-layer headbox, a stock concept is passed which has been produced out of the same fresh stock by adding the necessary chemicals and fillers to separated portions of the fresh stock. Into the stock feed system of the multi-layer headbox, at least one dilution-water line is passed.

Stock feed system for a multi-layer headbox and method in the operation of a multi-layer headbox

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 twin-wire gap former in a paper machine in which an outer wire and an inner wire are guided by guide rolls and by web forming members. The wires form a twin-wire zone which starts from a forming gap into which a slice part of a headbox feeds a stock suspension jet. The forming gap is followed by a curved portion of the twin-wire zone which is guided by a first forming roll placed inside the loop of one of the wires. The forming-gap arrangement includes two opposite tip plates which define a slice channel between them. The lip plates extend deep into the forming gap so that the free ends of the lip plates are placed in direct vicinity of the forming wires or in contact with the wires. On the curve sector of the twin-wire zone, which starts after the forming gap and which is guided by the first forming roll, inside the loop of one of the wires, a water drainage box is provided, at which box the edges of the sides that are placed against the inner face to the wire are substantially sealed. The water drainage box is connected to devices which regulate the pressure/pressures in the space or spaces placed in the interior of the box and are filled with water. Then, the drainage of water is controlled both in the forming gap and on the curve sector following after the forming gap.

Twin-wire gap former in a paper machine

A stock feed system for a multi-layer headbox in which a stock concept is passed into each inlet header in the multi-layer headbox. The stock concepts are produced out of the same fresh stock by adding chemicals and fillers to divided portions of that fresh stock. To this end, the system includes a single fresh-stock container, and stock lines into which the fillers, additives and equivalent are added in compliance with the requirements of each concept. The stock feed system also includes at least one fiber distributor for transferring long fibers out of the stock that is destined to form the surface layer of the paper into the stock that is destined to form a layer placed in the interior of the paper, preferably the middle layer. Fibers having a shorter length, compared with the average distribution of fibers in the basic stock derived from the stock container, are allowed to remain in the surface layer of the paper/board, and longer fibers, compared with the average distribution of fibers, are allowed to remain in the middle layer and/or are transferred into the middle layer.

Stock feed system for a multi-layer headbox and method in the operation

A method and device in the regulation of a headbox. The headbox includes a pulp inlet header, after the pulp inlet header, seen in the pulp flow direction, a distributor manifold whose pipes are opened into an intermediate chamber. The headbox comprises an attenuation chamber placed in connection with the intermediate chamber and, after the intermediate chamber, a turbulence generator having tubes which are opened, at their outlet end, into a discharge duct and, at their inlet end, into the intermediate chamber. In the method, into different positions along the width of the headbox, a pulp suspension flow is introduced, the concentration of this flow is adjustable by combining two component flows. In the method, in the regulation of the concentration of the flow passed into the pulp suspension, two component flows are combined by into the pulp suspension flow introducing an additional flow. The mixing ratio of the combined flow is regulated by adjusting the additional component flow. In the method, the additional component flow is passed into the pulp flow taken out of the inlet header.

Method and device in the regulation of a headbox

A hybrid former in a paper machine including a lower-wire loop in which there is an initial single-wire portion of a forming zone. In this initial portion, there are draining elements inside the lower-wire loop and thereafter wire-guide and draining elements. The former includes an upper-wire unit in which an upper wire is guided by guide rolls and by a breast roll onto a pulp layer formed on the single-wire portion of the lower wire. In a subsequent twin-wire portion following the single-wire portion, there is a draining and forming unit which includes at least one pressure-loaded press unit and at least one draining-chamber and support unit, which units are arranged inside opposite wire loops. In the units, there are sets of ribs which are pressure-loaded against each other. At the beginning of the twin-wire portion, inside the lower-wire loop, there is a revolving guide and forming roll which is in tangential contact with the lower wire or curves the twin-wire portion at a small angle which is in a range from about 0.degree. to about 5.degree.. The guide and forming roll is substantially immediately followed by the draining and forming unit which includes the sets of ribs. In the area of the draining and forming unit, water is drained primarily through the upper wire while aided by the negative pressures in the draining chamber or chambers in the unit.

Hybrid former with an MB unit in a paper machine

A twin-wire web former in a paper machine, having a single-wire initial portion, after which a twin-wire zone starts in the area of a ribbed deck of a first forming shoe placed inside one of the wire loops. After the first forming shoe, a pressure-loaded dewatering unit is arranged and which includes opposite sets of ribs and dewatering chambers. A first dewatering chamber in the dewatering unit is placed above the first forming shoe so as to remove water that drains from the area of the curved ribbed deck of the first forming shoe through its suction-deflector duct. The first dewatering chamber is followed by a second dewatering chamber, whose lower part is connected with a set of dewatering and guide ribs having gap spaces into which a drain duct of the second dewatering chamber opens. Against the set of dewatering and guide ribs, a set of loading ribs operates, which is placed inside the opposite wire loop and which operates by means of the medium pressure of loading hoses.

Twin wire web former in a paper machine

A method, device, and arrangement in a paper machine for regulating the control of the transverse profile or profiles of properties of a paper web produced therein. Water is removed from the paper web under compression between two forming wires by making use of dewatering and/or forming ribs. The deflection of the dewatering and/or forming ribs in the transverse direction of the web is regulated thereby affecting the retention profile of the paper web in the cross direction. By regulating the deflection of the dewatering and/or forming ribs, the transverse fiber-orientation profile and/or the filler profile of the paper web is influenced through the control of the transverse retention profile of the web.

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Muurame, Finland

Ari Linsuri