Patent ID: 7758726
Filing Date: 2010-07-20
Classification: B02C,D21D

Abstract:
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.