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Headbox and sheet forming unit with headbox

A headbox, sheet technology, used in textiles and paper, paper machines, wet end of paper machines, etc., to optimize the distribution of fibers and filler materials

Active Publication Date: 2016-03-16
VOITH PATENT GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] The known measures are not sufficient to suppress or reduce reflocculation on the desired scale at higher material densities of fibrous material suspensions, for example above 1.0 percent, in particular above 1.2 percent

Method used

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  • Headbox and sheet forming unit with headbox
  • Headbox and sheet forming unit with headbox
  • Headbox and sheet forming unit with headbox

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0063] A single hydraulic unit E of the turbulence generating device 6 H It is designed as an outlet pipe with a square cross-section. The side lengths t1 and t2 are 25 mm. The wall thickness d is 1 mm. Divide area B T Generated by:

[0064] B T =t1·t2=625mm

[0065] The length L of the nozzle 4 corresponds to

[0066] L = k · B T

[0067] Between 250mm and 500mm. This length range makes possible a sufficiently short residence time while simultaneously maintaining a sufficiently high jet quality.

[0068] The outlet ratio z yields a value of 0.84 for the k=10 embodiment.

[0069] The solution according to the invention is suitable for designing the headbox 1 with or without a membrane. The important thing here is to depend on the division area B T The length L of the nozzle 4 is properly selected, and the divided area corresponds to the part of a single hydraulic un...

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PUM

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Abstract

The invention relates to a headbox (1) comprising at least one feeding device (5) feeding at least one fibrous material suspension (FS), a nozzle (4) having an outlet gap (11) for dispensing the fibrous material suspension (FS) in a free jet and a turbulence-generating device (6) arranged directly upstream of the nozzle (4) in the flow direction. During operation of the headbox (1), the at least one fibrous material suspension (FS) is guided in partial flows through a plurality of turbulence-generating channels (7, 7.xy, 7.11 -7.4n), at least one region forming a fluidization region (12, 12.11 -12.31) being provided inside each individual turbulence-generating channel (7, 7.xy, 7.11 -7.4n). The headbox (1) according to the invention is characterized in that the nozzle (4) has a length (L) which is a function of the size of the proportional surface of the cross-sectional surface at the inlet of the nozzle, which proportional surface is associated with an individual turbulence-generating channel and represents a dividing surface (BT): L = k ° vBT, wherein L is the length of the nozzle (4); k is a constant, with 10 = k = 20; and BT is the dividing surface.

Description

technical field [0001] The invention relates to a headbox for use in a machine for producing a fibrous web, in particular a paper web, a cardboard web or a tissue web, from at least one suspension of fibrous material, comprising: at least one input at least one An input device for a fibrous material suspension; a nozzle with an outlet slit for discharging the fibrous material suspension in a free jet and a turbulence generating device directly preceding the nozzle in the direction of flow, in which at least one A fibrous material suspension can be conducted in a split-flow manner through a plurality of turbulence-generating channels, wherein at least one region forming a fluidization region is arranged within the individual turbulence-generating channels. [0002] The invention also relates to a sheet forming unit for a machine for producing fibrous webs, in particular paper webs, cardboard webs or tissue webs, comprising a headbox and a forming unit downstream of the headbox ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21F1/02
CPCD21F1/02D21F1/026D21F1/028
Inventor 汉斯·洛泽马库斯·豪斯勒沃尔夫冈·鲁夫
Owner VOITH PATENT GMBH