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Headbox, sheet-forming unit having a headbox and method for operating a sheet-forming unit

A headbox and turbulent flow technology, applied in the direction of textiles and papermaking, paper machine, paper machine wet end, etc., can solve the problems of unsuitable single fiber suspension residence time, compression, etc., to optimize the distribution of fibers and fillers or Effect of shaped, compact construction

Inactive Publication Date: 2012-07-11
VOITH PATENT GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] However, all known measures are not suitable for compressing the residence time of the individual fiber suspension below its reflocculation time, especially at higher substance concentrations

Method used

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  • Headbox, sheet-forming unit having a headbox and method for operating a sheet-forming unit
  • Headbox, sheet-forming unit having a headbox and method for operating a sheet-forming unit
  • Headbox, sheet-forming unit having a headbox and method for operating a sheet-forming unit

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Embodiment Construction

[0045] figure 2 In the simplified schematic diagram, the influence of the substance concentration SK in the fiber suspension FS on the composition is explained based on the graph. For this reason, the floc structure FL in the free bundle is plotted against the substance concentration SK in the form of the size of the formed floc. This shows the relationship between the high substance concentration SK and the uneven and coarse composition in the arrangement of the fibers and the filler due to the increased fiber flocculation, that is, in the case of the conventional known headbox Next, there is a tendency for larger flocs in the fiber suspension in the free bundle F in the outlet gap of the headbox. It is also obvious that in a fiber suspension with a lower substance concentration, here is 1.2% substance concentration characteristic value SK X Below, the floc formation is low, that is, only smaller flocs are observed in the free jet F at the exit gap of the headbox. figure 2 O...

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PUM

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Abstract

The invention relates to a headbox (1) for a machine for producing fibrous material webs from at least one fibrous material suspension (FS), comprising at least one feed device (4) feeding the at least one fibrous material suspension (FS), a nozzle (9) having an outlet gap (12) for dispensing the fibrous material suspension (FS) in a free jet (F), and a turbulence-generating device (7) arranged directly upstream of the nozzle (9) in the flow direction. During operation of the headbox (1), the at least one fibrous material suspension (FS) is guided in the turbulence-generating device in sub-flows through a plurality of turbulence-generating channels (8; 8.1-8.n; 8.11-8.nn). Within the individual turbulence-generating channel (8; 8.1-8.n; 8.11-8.nn) of the turbulence-generating device (7), at least one region forming a fluidisation region (15) is provided, in which a pressure loss (deltap) can be generated in the sub-flow of the fibrous material suspension (FS) guided through said region. The headbox (1) according to the invention is characterised in that the nozzle (9) and the turbulence-generating device (7) arranged directly upstream of the nozzle (9) are designed and dimensioned such that they are suitable for setting a dwell time (TV) of <= 200 ms of the fibrous material suspension (FS) flowing through the same from a final fluidisation region (15) of an individual turbulence-generating channel (8; 8.1-8.n; 8.11-8.nn) of the turbulence-generating device (7) before inlet (14) into the nozzle (9) as far as the outlet gap (12) of the nozzle (9), and a pressure loss (deltap) of >= 50 mbar in the final fluidisation region (15) upstream of the inlet (14) into the nozzle (9).

Description

Technical field [0001] The present invention relates to a headbox for a machine for making a fiber web from at least one fiber suspension, in particular a paper web, cardboard web or tissue paper web, with at least one fiber Suspension feeding equipment, nozzles with outlet slits for giving fiber suspension in free bundles, and turbulence generating devices directly upstream of the nozzles in the direction of flow, in which the turbulence generating devices flow During the operation of the headbox, at least one fiber suspension is guided into several sub-flows through multiple turbulence generating channels, wherein at least one area forming a fluidized area is provided in a single turbulence generating channel of the turbulence generating device, wherein Pressure loss can occur in the substream of the fiber suspension that is guided through this area. [0002] The invention also relates to a web forming unit for a machine for manufacturing fiber webs, in particular paper webs, c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21F1/02D21F9/00D21F9/02
CPCD21F1/026D21F9/02D21F1/028D21F1/02D21F9/003
Inventor H.洛瑟M.豪斯勒V.施密特-罗尔W.拉夫
Owner VOITH PATENT GMBH
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