Spare part for disc refiners for the production of paper

• US 8,870,109 B2
• Filed: 08/05/2011
• Issued: 10/28/2014
• Est. Priority Date: 08/06/2010
• Status: Active Grant

• Current Assignee: Officine Airaghi S.r.l.
• Original Assignee: Officine Airaghi S.r.l.
• Inventors: Ghibellini, Luca, Ghibellini, Michele
• Primary Examiner(s): Francis, Faye
• Application Number:
  US13/204,576
• Publication Number:
  US 20120032010A1
• Time in Patent Office: 1,180 Days
• Field of Search: 241/261.3, 241/261.2, 241/296, 241/298
• US Class Current: 241/261.3
• CPC Class Codes: D21D 1/306 Discs

Abstract

A spare part for disc refiners with a stator and/or rotor used in a disc refiner for low consistency pulp and paper refining with a dry fiber residue between 2% and 6%. The stator and/or rotor each comprise a disc-shaped metallic element with a refining blade surface having alternating bars and grooves. The rotor is designed to be driven and rotated around its own axis of rotation which passes through the center of the disc-shaped element so that the rotor bars perform a rotary movement in front of the stator bars with a suitable air gap in between. The blade surfaces or pattern have a pre-set angle greater than 0° with respect to a plane perpendicular to the rotor axis of rotation. This enables advantages in terms of the quantity and the quality of the refined product, and the potential to reduce the energy consumed.

Claims

1. A method of operating a disc refiner for refining a low consistency paper pulp, comprising the steps of using a disc refiner, providing a pair of refining discs for the refiner, said pair of refining discs being a stator and a rotor, both the stator and the rotor including a disc-shaped metallic element with a refining surface having alternating bars and grooves, wherein the stator and the rotor surfaces are always parallel to each other, and having a pre-set inclination angle greater than 0°

in respect of a plane perpendicular to the rotor axis of rotation, wherein all the bars of the stator and the rotor surfaces having the same height and all the grooves of stator and the rotor surfaces having the same depth and the opposed surfaces of both the stator and the rotor have inclined profiles in cross section, the method further including the steps of driving the rotor to rotate around its own axis of rotation, passing the axis through the center of the disc refiner, performing a rotary movement with the rotor bars in front of the stator bars with a gap in between, providing said gap with a constant height over the whole surfaces of the opposed discs, and wherein the fibers are not refined individually but in flakes with consistency between 2% and 6% where low density refinement is located and fibers are not free to move independently.

2. The method according to claim 1, in which the blade surfaces or pattern seen in a side cross section includes at least one of a rectilinear or curvilinear profile.

3. The method according to claim 2, in which the side cross section profile is uniformly rectilinear and has a constant angle.

4. The method according to claim 2, in which the side cross section profile comprises a curved line.

5. The method according to claim 2, in which the side cross section profile comprises rectilinear segments angled differently.

6. The method according to claim 2, in which the side cross section profile comprises an assembly of rectilinear and curved elements.

7. The method according to claim 2, in which the side cross section profile substantially has a saw-tooth shape.