Valmet Corporation

Valmet Paper Machinery Inc.

Metso Paper Inc.

Valmet Technologies, Inc.

Michael H Odell

Jyrki Huovila

Jyrki Jaakkola

Petri Nyberg

Jouko Aula

Mauri Koivuranta

Pekka Evasoja

Ari Linsuri

Lauri Verkasalo

Juhani Niskanen

Kari Juppi

Antti Komulainen

Antti Poikolainen

Ari Puurtinen

Petter Honkalampi

Hannu Korhonen

Erkki Ilmoniemi

Martti Salminen

Antti Suonper&auml;

Markku Lummila

Erkki Partanen

Sami Anttilainen

Jeffrey C Irwin

Riikka Antikainen

Martti J Salminen

An arrangement and method for improving runnability, and dryer section length, by using a vertical impingement dryer before a first dryer cylinder of a group of dryer cylinders. After a pressing section, the web is dried with a pre-impingement dryer, closely followed by a vertical impingement dryer, which is closely following by the first dryer cylinder. The pre-impingement dryer and vertical impingement dryer of the first dryer cylinder to have a drying temperature of approximately 80&#xb0; C. with no undesirable sticking to the dryer cylinder. The pre-impingement dryer can be arranged to dry a first side of the web, and a vertical impingement dryer after the first dryer cylinder is arranged to dry a second side of the web. The impingement drying takes place directly against the web without an intervening fabric.

Arrangement in a paper machine

Fibrous stock is supplied by a paper or board machine headbox () between looped forming wires (). Water is removed in a first dewatering zone (Z) formed with a fixed forming shoe () having a curved surface against which a wire () is supported while the opposite wire () is unsupported in the area of the shoe (). Water is removed in a second dewatering zone (Z) formed by fixed dewatering blades () on the other side of the wires () and supported against the stock therebetween () and on the opposite side of the wires () by dewatering blades (), loaded in a controlled manner against the fixed dewatering blades () at gaps () between these so that pulsating dewatering is caused in the second zone (Z). The wires () are guided so the shoe () causes essentially non-pulsating dewatering in the stock.

Forming of a paper or board web in a twin-wire former or in a twin-wire section of a former

A twin-wire former in a paper machine has two forming wire loops ( ), which define between themselves a twin-wire zone. At least one dewatering box ( ) is located inside one of the wire loops ( ) to remove water through the wire from a web (W) being formed. At least one loading blade ( ) is located opposite the dewatering box ( ) inside the other wire loop ( ) in contact with the other wire. The dewatering box ( ) includes at least three successive dewatering zones ( ) in which every second zone ( ) has a vacuum (p) and every second zone ( ) is vacuum-free. The at least one loading blade ( ) is placed inside one of the wire loops ( ) at a location where it is opposed by a respective vacuum-free zone ( ), which is preceded and followed by a vacuum zone ( ).

Twin-wire former

The invention concerns the short circulation of a paper or board machine and in particular a simplified process arrangement for the short circulation, which arrangement comprises a metering system ( ) for the stock (M) or stocks, pumps ( ), a headbox ( ), and a wire part ( ) as well as a pipe system interconnecting the devices, with means of regulation, and in which arrangement a high-consistency stock ( ) is fed into the headbox ( ), and the white water ( ) recovered from the wire part ( ) is fed by means of a diluting pump ( ) into the headbox ( ) so that diluting of the stock suspension is carried out in the headbox.

Process arrangement for short circulation

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.

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

A twin-wire former of a paper machine, for high speed paper machines whose web running speed is of an order of from about 1600 m/min to about 2500 m/min. The former includes a carrying wire guided in a loop and a covering wire guided in a loop to define a twin-wire zone and an inlet or forming gap between the wires. A pulp suspension layer or a pulp suspension jet is fed into the inlet or forming gap through a discharge duct of a headbox. The former also includes, as a combination, a first forming-suction roll arranged proximate the forming gap in a loop of one of the wires and a second forming-suction roll arranged inside the loop of the wire opposite to the wire inside whose loop the first forming roll is arranged. The forming-suction rolls have suction zones over which the twin-wire zone is curved on certain sectors. In the suction zones, the vacuum levels are arranged adjustable independently from one another, and possibly relative to one another, so as to minimize the unequalsidedness of the web. After the second forming-suction roll, there is a pressure pulsation unit in the twin-wire zone.

A roll and blade gap former for a paper machine having first and second wires guided in a respective loop and defining a twin-wire forming zone, a forming gap in which the first and second wires converge before the twin-wire zone, a headbox including a slice channel having a slice opening through which a stock suspension jet is fed into the forming gap to form a web between the wires, and drainage and forming elements arranged in the twin-wire zone for removing water from the web. To provide an improvement in the control of the Z-direction properties of the web, the former includes turbulence generating vanes arranged in the slice channel in the headbox to cause turbulence in the stock suspension jet upon its discharge from the slice opening into the forming gap and a first forming roll arranged in the twin-wire zone and which constitutes the first drainage and forming elements in the twin-wire zone after the forming gap. A run of the twin-wire zone after the forming gap is curved over a wrap angle sector of the first forming roll which is less than about 25.degree.. The forming and draining elements produce a pulsating pressure effect on the web after the curved run of the twin-wire zone over the wrap angle sector of the first forming roll. A method for controlling the anisotropy of web formed in a roll and blade former is also described.

Controlling web anistropy in a roll and blade twin-wire gap former

A former section provided with a twin-wire zone in a paper machine including a carrying wire and a covering wire which form the twin-wire zone therebetween them, and web-forming and draining members arranged in the twin-wire zone. In an initial part of the twin-wire zone, a stationary unit of forming ribs is arranged inside a loop of one of the wires and includes transverse forming ribs extending across the entire width of the wires and placed at a distance from one another to define gaps therebetween. A loading unit is placed opposite to these forming ribs inside the loop of the opposite wire and includes spring blades which are loaded against that wire. The dragging and loading areas of these spring blades are placed substantially in the middle areas of the gaps between the forming ribs in the stationary unit of forming ribs to prevent crushing of the web between the forming ribs in the stationary unit of forming ribs.

Web former in a paper machine

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

The invention is related to a twin-wire web former in a paper machine having a covering wire and a carrying wire which form a twin-wire forming zone with one another. A discharge opening of a headbox feeds a pulp suspension jet into the forming gap defined between said wires. The forming gap is immediately followed immediately by a forming shoe provided with a curved guide deck. A draining unit or units is/are provided after the forming shoe, before the first forming roll. The draining unit/units comprise(s) a press/support unit which guides the wire placed in contact with it as a straight run. The draining unit or units further comprise(s) a draining equipment provided with suction and foil equipment and placed opposite to the press/support unit, which draining equipment removes a substantial amount of water out of the web.

Twin-wire web former in a paper machine

The invention relates to a twin-wire web former for a paper machine wherein a covering wire and a carrying wire form a twin-wire forming zone between them. A method for dewatering a web is also disclosed. In the invention, water is drained out of a web running through the twin-wire zone through both of the wires. After the twin-wire zone, the web is separated from the covering wire and is transferred on the carrying wire to a pick-up point. In hybrid formers, after an initial single-wire forming zone preceding the twin-wire zone, and in gap formers, after a curved forming zone placed directly after a forming gap, there is a forming shoe provided with a ribbed deck and arranged inside one of the wire loops. This forming shoe is followed by dewatering and web forming units which include forming ribs and are placed inside both of the wire loops. At least one of the dewatering and web forming units is loaded by means of a pressure-hose arrangement.

Web former for a paper machine

A multi-layer headbox including at least two inlet headers for stock through which separate stocks are passed into a system of distributor pipes and further through a turbulence generator into a slice cone narrowing in the stock flow direction. Flaps are placed in the slice cone and one end of the flaps is attached to the turbulence generator. The flaps have at least two flap faces between which a step is formed. The step is arranged on the flap in an area in which the flap, and the flow duct, is curved and its the function is to dissipate any secondary vortices that might form on the curved flap face.

Multi-layer headbox

Web former for a paper machine with spring blade loading device

A method and device for the regulation of a pulp suspension flow in a multi-layer headbox and a multi-layer headbox for a paper machine/board machine. For the formation of different layers in the web, at least two pulp suspensions having different pulp concepts flow through the multi-layer headbox. The flow of a pulp suspension that forms one of the layers in the web is regulated by regulating the component flows that constitute this flow and regulating the concentration of the component flows independently from one another. In this manner, i.e., by regulating only this the particular layer, the total flow of the pulp suspension leaving the headbox is regulated.

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Jyvaskyla, Finland

Michael H Odell