Method and apparatus in a paper or board machine for confining pulp flow from the headbox

Abstract

A method in a paper or board machine for confining a pulp flow coming from the headbox (1), in which by at least one deckle part (2) being above the wire in the operating position the pulp flow coming from the headbox is confined in the lateral direction in the edge area of the wire (3). In the method, by a support part (50) impervious to liquid being below the wire (3) together with the deckle part (2) into connection with which liquid is brought, a pressure effect is provided which furthers the sealing between the deckle board (2) and the wire (3) and intensifies the lubrication of at least one sealing surface of the deckle (2). The invention also relates to an apparatus.

Description

BACKGROUND OF INVENTION [0001]The invention relates to a method according to the preamble of claim 1 in a paper or board machine for confining a pulp flow coming from the headbox, in which by at least one deckle part being above the wire in the operating position the pulp flow coming from the headbox is confined in the lateral direction in the edge area of the wire.[0002]The invention also relates to an apparatus according to the preamble of claim 11 in a paper or board machine for confining a pulp flow coming from the headbox, which apparatus comprises at least one deckle part being above the wire which in the operating position is arranged to confine the pulp flow coming from the headbox in the lateral direction in the edge area of the wire.[0003]The apparatus being the object of the invention is typically referred to as a deckle. Its function is to confine the flow of stock discharged from a slice of the headbox onto the wire in the lateral direction on the edges of the wire. The...

AI Technical Summary

Benefits of technology

[0005]The method according to the invention is mainly characterised in that, in the method, by a support part impervious to liquid being below the wire together with a deckle into connection with which liquid is brought, a pressure effect is provided which furthers the sealing between the deckle board and the wire and intensifies the lubrication of at least one sealing surface of the deckle.

[0007]The apparatus according to the invention is mainly characterised by a combination which comprises a support part impervious to liquid being below the wire and a deckle part into connection with which liquid is brought such that a pressure effect is provided which furthers the sealing between the deckle board and the wire and intensifies the lubrication of at least one sealing surface of the deckle.

[0009]The arrangement according to the invention has numerous significant advantages. By the support part impervious to liquid being below the wire together with the deckle into connection with which liquid is brought, a pressure effect is provided which furthers the sealing between the deckle board and the wire and intensifies the lubrication of at least one sealing surface of the deckle. Then, it has been possible to reduce or even completely prevent the formation of edge undulations and to reduce the range of basis weight variation in the edge area of the machine. Correspondingly, it has been possible to make the width of the edge area of reduced basis weight narrower. The runnability of the machine is improved and the width of the pulp web can be increased, whereby productivity is improved. The mechanical adjustments of the deckle do not change in connection with maintenance and wire change situations. The number of adjustment points has been substantially reduced, whereby the number of adjustments to be carried out by personnel is minimised. The arrangement enables an automation system to control the flow volumes of water in connection with the deckle on a quality-specific basis in accordance with speed. The fastening of the apparatus in the headbox is easy and it can also be automated. The deckle is easy to detach during a wire change from the tending side of the machine. The structure permits different water supply requirements at different points of the deckle. The structure of the deckle is sturdy. The deckle remains straight and does not get twisted and / or curved.

Problems solved by technology

After the stock has advanced through some distance on the wire in the machine direction and a sufficient volume of water has been removed from it, this problem disappears.

A problem of known prior-art arrangements is, inter alia, that the sealing effect and the lubrication properties of the deckle have proven deficient in practice and this has had an impact on the pulp as susceptibility to the formation of undulations, among others.

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