US4298425A — Method and apparatus for refining lignocellulose-…

Claim 1

Independent Claim 174 words

In the method of producing pulp from lignocellulosic fibrous material in which the material is first subjected to a grinding operation in a steam pressurized defibrating apparatus of the rotating disc type and the resultant mass of separated fibers is blown by the accompanying steam into a steam separator where the steam is separated from the fiber mass to form a cottony wadding-like fiber mass suspended in a gaseous atmosphere and passed to a refiner of the rotating-disc type via a screw conveyor means rotating within a housing, the improvement enhancing the freeness and wet strength characteristics of the pulp, comprising: compacting said cottony wadding-like fiber mass during its passage through said housing by compressing it by said screw conveyor means to a ratio between 1:2 and 1:6 so as to permit steam generated between the discs of said refiner to escape through said conveyor means housing without interfering with the constant supply of fiber mass to the refiner and to permit the refining to be performed at a dry content of about 25-30%.

Claim 2

Dependent Claim 174 words

In the method of producing pulp from lignocellulosic fibrous material in which the material is first subjected to a grinding operation in a steam pressurized defibrating apparatus of the rotating disc type and the resultant mass of separated fibers is blown by the accompanying steam into a steam separator where the steam is separated from the fiber mass to form a cottony wadding-like fiber mass suspended in a gaseous atmosphere and passed to a refiner of the rotating-disc type via a screw conveyor means rotating within a housing, the improvement enhancing the freeness and wet strength characteristics of the pulp, comprising: compacting said cottony wadding-like fiber mass during its passage through said housing by compressing it by said screw conveyor means to a ratio between 1:2 and 1:6 so as to permit steam generated between the discs of said refiner to escape through said conveyor means housing without interfering with the constant supply of fiber mass to the refiner and to permit the refining to be performed at a dry content of about 25-30%.

Claim 3

Dependent Claim 20 words

The method according to claim 1, in which the fluffy cotton mass is compacted in gaseous atmosphere at atmospheric pressure.

Claim 4

Dependent Claim 167 words

In an apparatus for producing pulp from lignocellulosic fibrous material in which the material is first ground in a steam pressurized defibrator and the resultant mass of separated fibers blown by the accompanying steam into a steam separator where the steam is separated from the mass of separated fibers in the form of a cottony wadding-like fiber mass suspended in a gaseous atmosphere and passed to a further refiner of the rotating-disc type via a screw conveyor means rotating within a housing, the improvement comprising: a screw conveyor means provided with screw flights calibrated relative to the housing so as to compress the cottony wadding-like fiber mass at a ratio between 1:2 and 1:6 during its passage through the housing so as to permit steam generated between the discs of said refiner to escape into said conveyor means housing without interfering with the constant supply of fiber mass to the refiner and means to permit the refining to be performed at a dry content of about 25-30%.

Claim 5

Dependent Claim 167 words

In an apparatus for producing pulp from lignocellulosic fibrous material in which the material is first ground in a steam pressurized defibrator and the resultant mass of separated fibers blown by the accompanying steam into a steam separator where the steam is separated from the mass of separated fibers in the form of a cottony wadding-like fiber mass suspended in a gaseous atmosphere and passed to a further refiner of the rotating-disc type via a screw conveyor means rotating within a housing, the improvement comprising: a screw conveyor means provided with screw flights calibrated relative to the housing so as to compress the cottony wadding-like fiber mass at a ratio between 1:2 and 1:6 during its passage through the housing so as to permit steam generated between the discs of said refiner to escape into said conveyor means housing without interfering with the constant supply of fiber mass to the refiner and means to permit the refining to be performed at a dry content of about 25-30%.

Claim 6

Dependent Claim 40 words

Apparatus according to claim 3, in which the screw flights together with the surrounding housing form an interspace which in the direction of flow of the fiber mass has a cross section decreasing in a ratio between 1:2 and 1:6.

Claim 7

Dependent Claim 35 words

Apparatus according to claim 4, having at least one adjustable flap pivoted to the interior wall of the housing at the end proximate to the further pulp-preparation apparatus for additionally regulating the ratio of compression.

Claim 8

Dependent Claim 14 words

Apparatus according to claims 3, in which the screw conveyor means comprises twin screws.

Claim 9

Dependent Claim 37 words

Apparatus according to claims 3 or 5, in which the flights of the screw means have a portion of constant diameter proximate the inlet and a portion of progressively decreasing diameter proximate the further pulp preparation apparatus.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-11-02	1985-05-04	1985-11-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-11-02	1989-05-04	1989-11-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-11-02	1993-05-04	1993-11-03	$7700.00	Window Closed / Lapsed

Method and apparatus for refining lignocellulose-containing material to produce fiber pulp

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