Refiner for the refining of paper pulps and the like

Abstract

 A refiner for the refining of paper pulps or the like, comprising oppositely placed refiner blades (2, 3), at least one of which rotates, an intake (11) for the pulp to be refined and an outlet (12) for the refined pulp. A drawback with conventional refiners is that the pulp fed into the refiner is not refined uniformly because there is no provision for selecting the pulp fractions to be refined. The invention solves this problem in that one or more of the refiner blades (2, 3) are provided with one or more top separators (6) which are at least partially conical and fixedly connected to the blades.

Description

[0001] The present invention relates to a refiner for the refining of paper pulps or the like, comprising oppositely placed refiner blades, at least one of which rotates, an intake for the pulp to be refined and an outlet for the refined pulp.

[0002] Refiners can be roughly divided into two categories: disc refiners and conical refiners. These are well known, so their construction will not be explained in detail here. An essential drawback with previously known refiners is that the pulp fed into the refiner is not refined uniformly because there is no provision for selecting the pulp fractions to be refined.

[0003] The object of the present invention is to achieve a refiner which is free of the drawback referred to, part of the pulp to be refined being divided into two different fractions, one of which is returned to the input and the other to the output of the refiner, or the fractions are passed out of the refiner. The refiner of the invention is characterized in that one or more of the refiner blades are provided with one or more at least partially conical, fixedly mounted top separators, and that the upper part of the cone of the top separator opens into the space between the refiner blades, so that the speed difference between the blades both feeds pulp into the top separator and produces the necessary rotary motion of the pulp in the top separator.

[0004] One of the advantages of the invention is that it makes it possible to choose the desired pulp fractions to be refined.

[0005] In the following, the invention is described in detail by referring to the attached drawings, in which

Fig. 1 presents a transverse cross-section through the selective refiner of the invention, illustrating the principle of its construction.

Fig. 2 presents a vertical cross-section through the selec­tive refiner of the invention, showing the various posi­tions where the top separator can be placed.

Fig. 3 presents a partial diagram representing the stator and rotor discs and the top separators mounted in conjunc­tion with them.

[0006] The selective refiner 1 of the invention illustrated in fig. 1 may be either a disc refiner or a conical refiner consisting of refiner blades 2, 3. At least one of the refiner blades is a rotary one, with a refining gap or zone 9 formed in the narrow space between the corresponding blade grooves 4, 5. In the embodiment illustrated by fig. 1, one of the refiner blades 2, e.g. the stator blade, is provided with a fixedly mounted conical top separator 6. The top part of the cone of the top separator opens into the space 4, 5, 9 between the refiner blades. The speed difference between the blades both feeds pulp into the top separator 6 and produces the necessary rotary motion of the pulp in the top separator. The top separator may be any type of conventional top separator provided with at least two outlets 7, 8 for different fractions. In the case of fig. 1, the lighter fraction is exhausted through the upper outlet 7 and the heavier fraction through the lower outlet 8.

[0007] Fig. 2 presents a conical refiner comprising refiner blades 2, 3 having the form of a truncated cone. In this case, the outer blade 2 is a stationary stator blade and the inner blade 3 is a rotating rotor blade whose axle 10 is mounted with bearings on the frame of the refiner. Moreover, the conical refiner comprises a pulp feed space 14 into which pulp is supplied mainly via the inlet 11, and an output space 13, from which the refined pulp is exhausted via the outlet 12. In fig. 2, both the stator and the rotor blades 2, 3 are provided with top separators 6 as illustrated by fig. 1. As can be seen from fig. 2, the feed opening of the top separator 6 can be placed in a desired location within the refining zone, and the top separator can be oriented in a desired direction relative to the direction of the pulp flow. The output orifices of the top separator may open inside the refiner, which is the case in fig. 2 in the case of the three uppermost top separators. Unlike these, the lowest top separator in the figure has output orifices 15, 16 opening outside the refiner.

[0008] The partial diagram in fig. 3 illustrates a solution which in principle is the same as in fig. 2, seen from the direc­tion of the axis of rotation of the rotor. Arrow 18 indi­cates the direction of rotation of the rotor 3.

[0009] It is obvious to a person skilled in the art that the in­vention is not restricted to the examples of its embodi­ments described above, but that it may instead be varied within the scope of the following claims.

Claims

Refiner for the refining of paper pulps or the like, comprising oppositely placed refiner blades (2, 3), at least one of which rotates, an intake (11) for the pulp to be refined and an outlet (12) for the refined pulp, characterized in that one or more of the refiner blades (2, 3) are provided with one or more at least partially conical, fixedly mounted top separators (6), and that the upper part of the cone of the top separa­tor opens into the space between the refiner blades, so that the speed difference between the blades (2, 3) both feeds pulp into the top separator (6) and produces the necessary rotary motion of the pulp in the top separator.

Drawing