Multi-layer headbox with plastic and metal divider plate
AssigneeVoith Sulzer Papiermaschinen GmbH
InventorsHelmut Heinzmann, Wolfgang Ruf, Ulrich Begemann, Thomas Dietz, Frank Fey
Life of this patent
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Abstract
A multi-layer headbox for the production of a multi-layer web of paper has, for instance, three flow planes (I, II, III), each having a pulp feed device (1.1, 1.2, 1.3). In each flow plane a turbulence generator (3) is provided which opens into a nozzle (4). In it there are two plates (5.1, 5.2) which keep two neighboring streams of slurry separate from each other up to the region of the exit slot (8). Each plate is developed as a flexurally soft plate of plastic, the downstream end of which is metal and has a thickness S of at most 0.3 mm. The plastic and metal have a different in coefficients of thermal expansion of <10.sup.-7 1/K.
Claims22
A multi-layer headbox forming a part of a machine for the production of a multi-layer fiber web, the machine having a machine width for producing a web of the machine width, the headbox comprising:
- at least two flow regions defining flow planes each conducting a fiber slurry, each flow plane having at least one feed device for the fiber slurry.
- a section in each flow plane for producing microturbulence in the fiber slurry;
- a nozzle coupled downstream to the sections for producing microturbulence;
- each section for producing microturbulence opening into the nozzle, the nozzle having an exit slot having a width comprising the machine width;
- at least one plate in the nozzle that keeps two adjacent streams of slurry separate from each other up to a region of the exit slot;
- the plate comprising a flexible plate extending from a region near the sections for producing microturbulence to a region of the exit slot, the plate having a base body of plastic and a downstream end of metal, the plastic and metal having a difference in coefficients of thermal expansion of <10.sup.-7 1/K;
- and
- the downstream end of the plate having a thickness S of at most 0.1 mm to 0.3 mm.
A multi-layer headbox forming a part of a machine for the production of a multi-layer fiber web, the machine having a machine width for producing a web of the machine width, the headbox comprising:
- at least two flow regions defining flow planes each conducting a fiber slurry, each flow plane having at least one feed device for the fiber slurry;
- a section in each flow plane for producing microturbulence in the fiber slurry;
- a nozzle coupled downstream to the sections for producing microturbulence;
- each section for producing microturbulence opening into the nozzle, the nozzle having an exit slot having a width comprising the machine width;
- at least one plate in the nozzle that keeps two adjacent streams of slurry separate from each other up to a region of the exit slot;
- the plate being mounted for free movement at an upstream end around a shaft which extends over the machine width transverse to a direction of flow of the fiber slurry, the plate having a base body of plastic and a downstream end of metal, the elastic and metal having a difference in coefficients of thermal expansion of <10.sup.-7 1/K;
- and
- the downstream end of the plate having a thickness S of at most 0.1 mm to 0.3 mm.
A multi-layer headbox forming a part of a machine for the production of a multi-layer fiber web, the machine having a machine width for producing a web of the machine width, the headbox comprising:
- at least two flow regions defining flow planes each conducting a fiber slurry, each flow plane having at least one feed device for the fiber slurry;
- a section in each flow plane for producing microturbulence in the fiber slurry;
- a nozzle coupled downstream to the sections for producing microturbulence;
- each section for producing microturbulence opening into the nozzle, the nozzle having an exit slot having a width comprising the machine width;
- at least one plate in the nozzle that keeps two adjacent streams of slurry separate from each other up to a region of the exit slot;
- the plate comprising a flexible plate extending from a region near the sections for producing microturbulence to a region of the exit slot, the plate being flexible to equalize pressures of the slurry streams on either side of the plate thereby to minimize eddy currents in the slurry streams at a downstream end of the plate and reduce oscillation of the plate, the plate having a base body of plastic and the downstream end of metal, the plastic and metal having a difference in coefficients of thermal expansion of <10.sup.-7 1/K;
- and
- the downstream end of the plate having a thickness S of at most 0.1 mm to 0.3 mm and being selected to minimize oscillation of the plate.
A multi-layer headbox forming a part of a machine for the production of a multi-layer fiber web, the machine having a machine width for producing a web of the machine width, the headbox comprising:
- at least two flow regions defining flow planes each conducting a fiber slurry, each flow plane having at least one feed device for the fiber slurry;
- a section in each flow plane for producing microturbulence in the fiber slurry;
- a nozzle coupled downstream to the sections for producing microturbulence;
- each section for producing microturbulence opening into the nozzle, the nozzle having an exit slot having a width comprising the machine width;
- at least one plate in the nozzle that keeps two adjacent streams of slurry separate from each other up to a region of the exit slot;
- the plate being mounted for free movement at an upstream end around a shaft which extends over the machine width transverse to a direction of flow of the fiber slurry, the plate being mounted for free movement to equalize pressures of the slurry streams on either side of the plate thereby to minimize eddy currents in the slurry streams at a downstream end of the plate and reduce oscillation of the plate, the plate having a base body of plastic and the downstream end of metal, the plastic and metal having a difference in coefficients of thermal expansion of <10.sup.-7 1/K;
- and
- the downstream end of the plate having a thickness S of at most 0.1 mm to 0.3 mm and being selected to minimize oscillation of the plate.
A multi-layer headbox forming a part of a machine for the production of a multi-layer fiber web, the machine having a machine width for producing a web of the machine width, the headbox comprising:
- at least two flow regions defining flow planes each conducting a fiber slurry, each flow plane having at least one feed device for the fiber slurry;
- a section in each flow plane for producing microturbulence in the fiber slurry;
- a nozzle coupled downstream to the sections for producing microturbulence;
- each section for producing microturbulence opening into the nozzle, the nozzle having an exit slot having a width comprising the machine width;
- at least one plate in the nozzle that keeps two adjacent streams of slurry separate from each other up to a region of the exit slot;
- the plate comprising a flexible plate extending from a region near the sections for producing microturbulence to a region of the exit slot, the plate having a base body of plastic and a downstream end of metal, the plastic and metal having a difference in coefficients of thermal expansion of <10.sup.-7 1/K;
- and
- the downstream end of the plate having a thickness S of at most 0.1 mm to about 0.2 mm.
A multi-layer headbox forming a part of a machine for the production of a multi-layer fiber web, the machine having a machine width for producing a web of the machine width, the headbox comprising:
- at least two flow regions defining flow planes each conducting a fiber slurry, each flow plane having at least one feed device for the fiber slurry;
- a section in each flow plane for producing microturbulence in the fiber slurry;
- a nozzle coupled downstream to the sections for producing microturbulence;
- each section for producing microturbulence opening into the nozzle, the nozzle having an exit slot having a width comprising the machine width;
- a baffle disposed in the nozzle and adapted to operatively engage the fiber web but not compensate for a basis weight of the fiber web;
- at least one plate in the nozzle that keeps two adjacent streams of slurry separate from each other up to a region of the exit slot;
- the plate comprising a flexible plate extending from a region near the sections for producing microturbulence to a region of the exit slot, the plate having a base body of plastic and a downstream end of metal, the plastic and metal having a difference in coefficients of thermal expansion of <10.sup.-7 1/K;
- the downstream end of the plate having a thickness S of at most about 0.1 mm to 0.3 mm;
- the headbox further comprising means for controlling density of the pulp fed to at least one of the flow planes comprising:
- a plurality of pulp slurry feed lines for at least one flow plane distributed over the machine width;
- a mixer provided in each pulp slurry feed line, each mixer comprising:
- at least two inlets and an outlet;
- at least one of the inlets of each mixer having means for regulating the flow;
- and
- individual feeds to each mixer having different properties.
Dependencies are inferred from the claim text.