Metso Paper Inc.

Valmet Technologies, Inc.

Janne Lappi

Jarmo Kirvesmäki

Antti Poikolainen

Sami Anttilainen

Janne Laakso

Riikka Antikainen

Ilkka Kemiläinen

Hannu Turpeinen

Ilkka Kemilaeinen

Jarmo Kirvesmaeki

Jussi Vasara

A forming section has a lower wire loop (), which constitutes a single-wire section (T) following a breast roll (). A first dewatering zone (Z) has at least one stationary, first forming shoe () followed by a pulsating strip cover (). The first forming shoe has leading and trailing edges and underpressure affecting through holes of the cover. The holes are openings or slots substantially in the longitudinal direction of the machine, whereby non-pulsating dewatering is applied on the stock travelling on top of the lower wire. A pulp suspension jet is fed from a headbox () at an impact point after the shoe leading edge. The cover is straight at least in the area between the impact point of the pulp suspension jet and the trailing edge. The impact of the pulp suspension jet on the forming wire is thus better controlled in a better way, increasing production speed.

Forming section

A vane intended for a headbox of a paper machine or equivalent is moistened and enclosed in a vapor-proof package to ensure the straightness of the vane. At least a portion of the vane is made of a water-absorbing material, such as plastic or a composite. Advantageously, the vane contains moisture in an amount that corresponds to the equilibrium moisture content of the vane in headbox conditions. It is enclosed in a package, preferably a vacuum package, which retains the moisture of the vane until the vane is put into use.

Vane intended for a headbox of a paper machine and method for ensuring the straightness of a vane

A headbox apparatus of a paper machine or equivalent has a body (). Dilution water (arrow L) is conducted through at least two rows of ducts (aa. . . ) into each body mixing chambers (aa. . . ). Each mixing chamber (aa. . . ) is limited by vertical walls (T), a bottom wall (T) and a covering wall (T), and a partition wall (aa. . . ). The ducts (aa. . . ) on the inlet side of the mixing chamber extend into the mixing chamber (aa. . . ) at a distance (h) from the ducts (aaa. . . ) on the outlet side of the mixing chamber (aa. . . ), whereby an annular gap (D) is left between the aligned duct (aaaa. . . ) on the inlet side and the duct (aaaa. . . ) on the outlet side. Each mixing chamber (aa. . . ) is filled by dilution water which is conducted through the annular gap (D) to join the stock (m).

Apparatus in connection with a headbox of a paper machine or equivalent

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Jyväskylä, Finland

Janne Lappi