Double-disc refiner comprising a center plate

Abstract

The invention relates to a double disc pulp refiner (10) comprising a first refining disc (11) and a second refining disc (12), the first refining disc being arranged at a feed end of the refiner (10) where lignocellulosic material (M) is fed into the refiner (10) through inlet openings (16) in the first refining disc (11) and the second refining disc (12) being arranged coaxially, spaced apart from and opposed to the first refining disc (11), said first refining disc (11) being provided with at least one refining segment (13) for refining the lignocellulosic material (M) and a center plate (20)having a cross-sectional profile adapted such that when the center plate (20) is arranged on the first refining disc (11) in the refiner (10), the center plate (20) protrudes to a maximum height which is the same as, or higher than, a maximum height of the at least one refining segment (13) provided on the first refining disc (11), said double disc pulp refiner (10), wherein said maximum height is such that the distance between the distal surface of said center plate and the surface of said second refining disc (12) is as small as possible without having their surfaces touching each other.

Description

technical field [0001] The present invention relates generally to disc refiners and, more particularly, to a double disc pulp refiner including a disc center plate. Background technique [0002] Twin-disc pulp refiners have been used for many years to refine pulp and similar materials by subjecting the pulp to the heat and stresses generated as it passes radially through closely spaced counter-rotating disks . As an example of the prior art, patent document US 5167373 describes a double-disc refiner in which two counter-rotating refiner discs delimiting a refining zone between them rotate counter-rotating at different speeds. [0003] figure 1 is a schematic diagram of part of a typical double disc refiner 10 according to the prior art, where the two refining discs 11, 12 rotate at different rotational speeds and / or in opposite directions, ie counter-rotate. The refiner 10 comprises a housing 17 into which raw material, such as lignocellulosic material M, is fed through a...

AI Technical Summary

Problems solved by technology

[0004] The problem with this type of refiner is that incoming material entering the refiner off-centre not only moves towards the periphery of the refining disc as desired, but also towards the center of the refining disc where material can build up, This can negatively affect the material distribution in the refiner

This can lead to uneven and turbulent material feed, resulting in higher specific energy consumption and lower productivity

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