Methods and apparatus for forming fluff pulp sheets

Patent metadata

Field	Value
Publication number	US-2017081802-A1
Application number	US-201615367520-A
Country	US
Kind code	A1
Filing date	Dec 2, 2016
Priority date	Feb 16, 2012
Publication date	Mar 23, 2017
Grant date	—

Abstract

An improved processes for making fluff pulp sheets mechanically eliminates many of the unwanted fiber-to-fiber bonding (fiber bundles) which may be contained in the sheet to produce consistent and uniform quality fluff pulp. Pulp slurry is deposited on a moving bottom forming wire to form a stock web. Pulp slurry is brought into contact with a moving top forming wire. The stock web is subjected to up and down dewatering creating separately formed layers to reduce fiber-to-fiber bonding. The stock web can be subjected to strong pulsating shear forces as it is being advanced along the bottom forming wire to break a majority of fiber bundles contained in the web. The pulp slurry can be deposited on the bottom forming wire utilizing a headbox with dilution control to selectively adjust the concentration of the pulp slurry. A shoe press can be used to dewater the web after it is subjected to the pulsating shear forces. The web can be dried utilizing conventional drying equipment, such as cylindrical driers.

First claim

I claim:

1 . A process for making a fluff pulp sheet, comprising:
creating a pulp slurry which includes pulp fibers suspended in a liquid, the pulp slurry containing multiple fiber bundles formed from pulp fibers which are bonded together and dispersed within the pulp slurry; applying an amount of the pulp slurry onto a moving bottom forming wire to form a web thereon, the pulp slurry being dispensed by a headbox; and controlling the cross-directional weight basis of the web by varying the concentration of the pulp slurry being deposited from the headbox onto the bottom forming wire.

2 . The process in claim 1 , further including:
applying a top forming wire onto the web and dewatering the web through the top forming wire to create a top fiber layer against the top forming wire.

3 . The process in claim 2 , further including:
dewatering the web through the bottom forming wire to create a bottom fiber layer against the bottom forming wire.

4 . The process in claim 3 , further including:
applying pulsating shear forces on the web as it moves on the bottom forming wire, the pulsating shear forces being sufficiently large to break some of the fiber bundles.

5 . The process in claim 4 , further including:
further dewatering liquid from the web after the web has been subjected to the pulsating shear forces.

6 . The process of claim 1 , further including:
applying heat to the web.

7 . The process of claim 1 , wherein liquid is added to the pulp slurry exiting the headbox to adjust the concentration of the pulp slurry prior to being deposited onto the bottom forming wire.

8 . The process of claim 2 , wherein the top forming wire contacts the web and the pulsating shear force is applied in a region where the top forming wire and bottom forming wire contact the web.

9 . The process of claim 2 , wherein the pulsating shear force is created by advancing the bottom forming wire over a series of upright members which cause the bottom forming wire to move in an up and down motion.

10 . The process of claim 9 , wherein a portion of the pulsating shear force applied to the web is created by subjecting the web to a vacuum source in the region where the bottom forming wire is advanced over the series of upright members.

11 . The process of claim 2 , wherein the top forming wire and bottom forming wire are components of a top former apparatus.

12 . A process for making a fluff pulp sheet, comprising:
creating a pulp slurry which includes pulp fibers suspended in a liquid, the pulp slurry containing multiple fiber bundles formed from pulp fibers which are bonded together and dispersed within the pulp slurry; applying the pulp slurry onto a moving bottom forming wire which moves the deposited pulp slurry in a forward direction to form a web, the pulp slurry being dispensed by a headbox; and adjusting the cross-directional weight basis of the pulp slurry by diluting at least a portion the concentration of the pulp slurry as it is being deposited from the headbox onto the bottom forming wire.

13 . The process of claim 12 , further including:
monitoring the cross-directional basis weight of the web.

14 . The process of claim 12 , further including:
applying a pulsating shear force of sufficient magnitude on the web to break some of the fiber bundles contained in the web.

15 . The process in claim 12 , further including:
applying a top forming wire onto the web and dewatering the web through the top forming wire.

16 . The process of claim 12 , further including:
contacting the web with a dewatering machine which further dewaters the web.

17 . The process of claim 16 , wherein the dewatering machine is a shoe press.

18 . A process for making a fluff pulp sheet, comprising:
creating a pulp slurry which includes pulp fibers suspended in a liquid, the pulp slurry containing multiple fiber bundles formed from pulp fibers which are bonded together and dispersed within the pulp slurry; placing the pulp slurry into a headbox having dilution control which allows the concentration of the pulp slurry to be diluted as the pulp slurry exits the headbox; applying the pulp slurry onto a moving bottom forming wire which moves the deposited pulp slurry in a forward direction to form a web; contacting the web with a top forming wire which cooperates with the bottom forming wire to dewater liquid from the web; contacting the web with a dewatering machine which contacts the web to remove some of the liquid from the web; and applying heat to the web to evaporate additional liquid from the web.

19 . The process of claim 18 , further including:
selectively adding liquid to the pulp slurry as it exits the headbox onto the bottom forming wire.

20 . The process of claim 18 , further including:
applying a second pulp slurry to the first mentioned pulp slurry to form a multilayer web.

Assignees

• Int Paper Co

Inventors

• Jaakkola Jyrki T
• Sealey James E

Classifications

• D21F3/045 Primary

  including at least one extended press nip · CPC title

• D21H27/30

  Multi-ply (for surface covering D21H27/18; making on paper-making machines D21F9/00, D21F11/00) · CPC title

• D21F11/14

  Making cellulose wadding, filter or blotting paper · CPC title

• D21F9/006

  paper or board consisting of two or more layers · CPC title

• D21H27/002 Primary

  Tissue paper; Absorbent paper (D21H21/22, D21H27/02, D21H27/20 take precedence; toilet paper A47K10/00; absorbent pads for physiological fluids A61L15/16; making on paper-making machines D21F11/00) · CPC title