Disc refiner with increased gap between fiberizing and fibrillating bands
First Claim
1. In a primary wood chip refiner having flat, relatively rotating discs, each having a working plate thereon, the working plates being arranged in confronting coaxial relation thereby defining a refiner gap which extends substantially radially outward from the inner diameter of the discs to the outer diameter of the discs and defines a flow area for the chip material to be refined, the improvement comprising:
- each plate having a radially inner fiberizing band and a radially outer fibrillating band, each band having an inner feeding region and an outer working region, the radial width of the inner band being less than about 35% of the total radius of the plate, wherein the working region of the inner band is defined by a first pattern of alternating bars and grooves, and the feeding region of the outer band is defined by a second pattern of alternating bars and grooves, and said flow area increases immediately after the inner working region into the outer feed region.
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Accused Products
Abstract
Plate elements, a plate configuration, and associated system for thermomechanical refining of wood chips wherein destructured and partially defibrated chips are fed to a rotating disc primary refiner, where opposed discs each have an inner band pattern of bars and grooves and outer band pattern of bars and grooves, such that substantially complete fiberization (defibration) of the chips is achieved in the inner band and the resulting fibers are fibrillated in the outer band. One embodiment is directed to a pair of opposed co-operating refining plate elements for a flat disc refiner wherein the bars and grooves on each of the inner bands form an inner feed region followed by an outer working region, the bars and groove on each of the outer bands form an inner feed region followed by an outer working region, and the gap and/or material flow area formed when the plates are placed in front of each other increases between the inner working region and the outer feed region.
28 Citations
18 Claims
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1. In a primary wood chip refiner having flat, relatively rotating discs, each having a working plate thereon, the working plates being arranged in confronting coaxial relation thereby defining a refiner gap which extends substantially radially outward from the inner diameter of the discs to the outer diameter of the discs and defines a flow area for the chip material to be refined, the improvement comprising:
- each plate having a radially inner fiberizing band and a radially outer fibrillating band, each band having an inner feeding region and an outer working region, the radial width of the inner band being less than about 35% of the total radius of the plate, wherein the working region of the inner band is defined by a first pattern of alternating bars and grooves, and the feeding region of the outer band is defined by a second pattern of alternating bars and grooves, and said flow area increases immediately after the inner working region into the outer feed region.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a disc refiner for lignocellulosic material, a pair of confronting, relatively rotating flat discs having respective refining plates, comprising:
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a first plate having inner and outer radii Ri, Ro and a working face including a pattern of raised and relief structures and an intermediate transition portion having an inner radius Ra and an outer radius Rb; a second plate having inner and outer radii Ri, Ro and a working face including a pattern of raised and relief structures and an intermediate transition portion having an inner radius Ra and an outer radius Rb; said plates having a radially extending gap between their working faces; whereby a radially dependent flow area A for the lignocellulosic material extends from the inner radius Ri to the outer radius Ro, such that
dA/dr<
0 from Ri to Ra
dA/dr>
0 from Ra to Rb
dA/dr<
0 from Rb to Ro
where Ri<
Ra<
Rb<
Ro. - View Dependent Claims (17)
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18. In a primary wood chip refiner having flat, relatively rotating discs, each having a working plate thereon, the working plates being arranged in confronting coaxial relation thereby defining a refiner gap which extends substantially radially outward from the inner diameter of the discs to the outer diameter of the discs and defines a flow area for the chip material to be refined, the improvement comprising:
- each plate having a radially inner fiberizing band and a radially outer fibrillating band, each band having an inner feeding region and an outer working region, wherein the working region of the inner band is defined by a first pattern of alternating bars and grooves and the feeding region of the outer band is defined by a second pattern of alternating bars and grooves, and a steam backflow channel being formed as a groove on the surface of the working region of the inner band, oriented diagonally through the bars and grooves of said pattern of bars and grooves.
Specification