WO1984002285A1

WO1984002285A1 - Device at refiner members

Info

Publication number: WO1984002285A1
Application number: PCT/SE1983/000429
Authority: WO
Inventors: Alf Ove Kenneth Johansson; Hans Erik Hoeglund; Per Viking Peterson
Original assignee: Sunds Defibrator
Priority date: 1982-12-15
Filing date: 1983-12-06
Publication date: 1984-06-21
Also published as: NO843233L; SE8207175D0; FI850155A0; JPS60500127A; AU2345484A; EP0158637A1; FI850155L; SE8207175L; SE441649B

Abstract

At the defibring/refining of cellulose-containing material, for example in the form of chips, it was found that the design of the refiner members, between which the processing takes place, the so-called refiner disc segments (Fig. 1), is of great importance for the properties of the resulting pulp and the consumption of energy at the processing. A refiner member is a plane disc, in which grooves are provided in such a manner, that between the grooves so-called bars are formed, which conventionally are formed with plane surfaces (10). According to the invention, these bar surfaces (13) have a slightly concave design with a deflection d (Fig. 3).

Description

Device at refiner members

This invention relates to disc refiners for the mechanical processing of cellulose material and refers to the members constituting the processing surfaces, so-called refiner disc segments.

Cellulose-containing material is defibred and refined by so-called refiners, which in many cases are of the disc refiner type. These refiners also are used for beating cellulose and mechanical pulps of various types when it is desired by mechanical processing to develop the paper-forming properties of these materials. All these defibring and refining operations have in common, that the desired result is obtained by mechanically processing the material while it is passing through the refiner. This processing effect is brought about in that the fibre material, after having been fed by various types of devices into the refiner, leaves the refiner through a narrow gap between two processing surfaces, which to this end are provided with processing members in the form of bars and intermediate grooves. Due to the rotation of one, and at times both said surfaces, the material is processed in the way desired and is transported out of the refiner by the rotation forces.

The intensity and type of processing the fibre material is determined a.o. by the design and number of the bars and grooves on the processing surfaces and also by the size of the gap. A certain wear of the refining surfaces cannot be avoided and, therefore, the disc refiner is provided, for practical reasons, with exchangeable refiner disc segments. These segments are provided at their manufacture with a pattern and profile adapted to the type of work to be carried out in the refiner. The energy required for defibring and processing is transferred to the fibre material via the edges and surfaces of the bars.

The design of a refiner disc segment is shown in Fig. 1. The pattern generally is divided into three zones22, 3 and 4 where in the outer zone 4 bars and grooves are designated by 5 and, respectively, 6. Fig. 2 shows how the bars conventionally are formed with walls 7,8 and a plane surface 10 so that a gap 9 is formed.

It can be stated that the design of the bars and grooves of the refiner disc segments is of importance for the energy consumption at the refining of cellulose material, especially at high concentration, above 20%. Even seemingly small variants in the refiner disc segment pattern can cause great variations in the energy consumption. The design of the patterns is very important also for the properties resulting from the refining/processing.

It was now found entirely by surprise that the energy consumption can reduced substantially and the properties be improved when the surface of the bars is designed in a definite manner.

According to the invention, this is achieved in that the surface slightly is curved downward along its centre line in relation to its edge.

The invention is described in greater detail in the following by way of some embodiments and with reference to the accompanying drawings, in which Fig. 3 is a cross-section of two opposed bars according to the invention, and Figs. 4-7 show other variants of the bar according to the invention. In Fig. 3 a cross-section of two bars is shown, which are located each on a refiner disc segment of contra-rotating refiner discs (not shown). The bars have walls 11,12 of conventional design. According to the invention, the processing surface 13 of the bars is formed with a concave deflection, which in the present case is at least 0,1 mm.

In Figs. 4 and 5 two further embodiments are shown, which are characterized in that the angle β between the bar surface 7 and at least the upper portion of the bar wall is smaller than 90º. At the embodiment according to Fig. 4, the wall consists of a straight vertical portion 13 and an inclined upper portion 12, so that a cutting edge 9 along the edge of the bar is formed.

According to Fig. 6, the processing surface has a depression with a plane bottom 17, which depression is defined by inclined or straight walls. Along the edges of the surface a plane edge zone 16 is formed.

In Fig. 7 an embodiment is shown where the depression is formed by two surfaces inclined to the centre line of the surface.

The invention is not restricted to the embodiments shown, but can be varied within the scope of the invention idea.

Claims

1. A refiner disc segment (1) for processing cellulose-containing material, provided with processing members in the form of bars (7) and grooves located between the bars, which bars have a substantially horizontal processing surface and substantially vertical walls (11), c h a r a c t e r i z e d i n that the processing surface has a coherent depression in relation to the edges of the surface, which depression extends across at least half the processing surface.

2. A processing member as defined in claim 1, c h a r a c t e r i z e d i n that the depression along the centre line of the surface is at least 0,1 mm, preferably at least 0,4 mm, in relation to the edges of the surface.

3. A processing member as defined in the claims 1 and 2, c h a r a c t e r i z e d i n that the processing surface has concave design (Fig. 3).

4. A processing member as defined in the claims 1 and 2, c h a r a c t e r i z e d i n that the depression has a substantially plane bottom (17), and that also the processing surface along its edge zones has a plane portion (16).

5. A processing member as defined in the claims 1 and 2, c h a r a c t e r i z e d i n that the depression is defined by two inclined surfaces (18), which extend from the edge (15) of the processing surface to the centre line thereof.

6. A processing member as defined in any one of the preceding claims, c h a r a c t e r i z e d i n that the angle (β ) between processing surface and at least the upper portion of the wall is smaller than 90°, preferably smaller than 80°, for example 70-80° (Figs. 4 and 5).

7. A processing member as defined in claim 6, c h a r a c t e r i z e d i n that the wall has a lower, substantially vertical portion (Fig. 4).