FI69137B - SKIVRAFFINOER - Google Patents

Description

691 37

KIEKKOOAtJtUN - .. SKiyBAPFINOB

When fast. The rotating disc of the grinder blade is fed with a mixture of wood chips or pinj. chips and water. steam, In order for the mechanical treatment of the fiber with the help of the blade brushes to take place thoroughly, it must be possible to slow down the radial outflow of the generated steam and pulp and thus the degree of filling of the blade gap. This is usually done by means of the grooves in the therapy surface and the design of the refining blade slot itself. The result may be satisfactory when the blade is new, but changes in an unfavorable direction within the blade.

Disc grinders are also known in which flow-slowing devices are mounted outside the circumference of the blade discs.

However, due to their complexity, these devices have not come into general use.

The invention thus relates to a disc grinder in which the grinder gap is delimited by two blade discs, at least one of which is rotatable, having approximately radial blade ridges in the blade surfaces facing each other and blade grooves therebetween and having a circumference so as to slow down the radial flow between the blade surfaces.

The object of the invention is to provide a new type of disc grinder in which the deceleration of the rainy flow takes place in a very simple manner. The invention is characterized in that at least one blade surface has at least one circumferential deceleration groove outside the blade ridges, the depth of which is greater than the depth of the blade grooves,

Due to the deceleration groove, the flow is forced to turn, which creates a vortex motion, which slows down the flow of mass in the radial direction »The effect is enhanced if both blade surfaces have one or more deceleration grooves in succession, 691 37 2

At least one "B.idas.tysura ^, gn" ns, Hidgstusgrat are thus located 1 qjci11ai'n so that the flow is forced to turn as it moves from one groove to another, At the same time the vortex motion intensifies, which further slows down the flow,

Another preferred embodiment of the invention is characterized in that the diameters of the blade brush area in the opposing grinding discs are of different sizes and that the deceleration grooves are located immediately outside the blade brush area. area of influence. This further contributes to the desired deceleration or call.

A preferred embodiment of the invention is further characterized in that the outer diameter of the second blade disc is smaller than the circumference 1 of the deceleration groove in the opposite blade disc so that the outer edge of the first blade disc can penetrate the deceleration groove in the opposite blade disc during the blade brushes. In this case, there is no risk of the outer edges coming into contact with each other, even if the blade discs are well worn. The true flow cross-section at the outer edge of the blade discs would not change during the blade brushes, the outer circumference of the smaller blade disc and the outer circumference of the deceleration groove in the opposite blade disc are axial, the deceleration effect is thus independent of the wear of the blade brush surfaces | li 69137

The invention will now be described by way of example with reference to the accompanying drawing, in which

Fig. 1 shows the second blade disc axonometrically as seen from the blade surface side.

Fig. 2 shows the edge portion of the blade disc shifted to a larger scale.

Fig. 3 shows in axial section the edge portions of two opposite blade discs in a situation where the blade brushes have not yet been worn.

Fig. 4 corresponds to Fig. 3 and shows a situation where the blade brushes are already worn.

In the drawing, reference numeral 1 denotes a second blade disc assembled from steel sectors 14. The blade surface of each steel sector 14 is provided with blade ridges 3 and intervening blade grooves 4, as best seen in Fig. 2. The direction of the blade brushes 3 is approximately radial but can vary widely, such as Figure 1 shows. In practice, there are a very large number of different blade surface patterns.

According to Fig. 3, on the blade surface of each blade disc 1, 2, outside the blade brushes 3 and 5, there is one circumferential deceleration groove 6 and 7, the depth of which is greater than the depth of the blade grooves 4 and Θ. The deceleration grooves 6 and 7 are not located exactly opposite to each other, but are displaced radially with respect to each other so that the diameter of the deceleration groove 6 is larger than the diameter of the deceleration groove 7. Each deceleration groove 6 and 7 is located immediately outside the blade-brush area 11a. Thus, the grinding disc 1 has a larger blade brush area than the grinding disc 2.

691 37 4

The outer diameter of the blade disc 2 is smaller than the outer diameter of the deceleration groove 6 in the blade disc 1. Thus, the outer edge 9 of the blade disc 2 can penetrate the deceleration groove 6 in the opposite blade disc 2 during the blade brushes 3 and 5, as shown in Fig. 4. The outer circumference 9 of the smaller blade disc 2 and the outer circumference 10 of the deceleration groove 6 in the opposite blade disc 1 are parallel to the axis of the blade discs. Thus, the cross-sectional area of the gap 11 between these rings is unchanged regardless of the degree of wear of the blade brushes 3 and 5.

As the pulp discharges at high speed radially out of the gap 12 between the blade surfaces, it is subjected to strong eddy movements. The vortex movements are caused by the free ends 13, the deceleration groove 7 and the deceleration groove 6 of all the blade brushes 3. All these vortex movements strongly slow down the flow of the pulp in the radial direction between the blade discs 1 and 2.

It will be apparent to those skilled in the art that various embodiments of the invention may vary within the scope of the claims set forth below. Thus, there can be only one deceleration groove located on either blade surface. On the other hand, the deceleration grooves may be several in succession on each blade surface.

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Claims (4)

69137 PATENT CLAIMS A disc grinder in which the grinder slot (12) is bounded by two blade discs (1,2), at least one of which is rotatable and having approximately radial blade ridges (3,5) and blade grooves (4,6) therebetween facing each other and having a circumference is formed in such a way that the radial flow between the blade surfaces is slowed down, characterized in that at least one blade surface has at least one circumferential deceleration groove (6,7) outside the blade ridges (3,5) with a depth greater than that of the blade grooves (4.8). ) depth. A disc refiner according to claim 1, having at least one deceleration groove (6,7) on each refiner surface, characterized in that the deceleration grooves (6,7) of different refiner surfaces are offset from each other in the direction of rain, Disc grinder according to Claim 1 or 2, characterized in that the diameters of the blade brush area in the opposing grinding discs (1, 2) are of different sizes and in that the deceleration grooves (6, 7) are located immediately outside the blade brush area. Disc grinder according to one of Claims 1 to 3, characterized in that the outer diameter of the second blade disc (2) is smaller than the outer diameter of the deceleration groove (6) in the opposite blade disc (1) so that the outer edge (9) of the first blade disc , 5) penetrating the deceleration groove in the opposite blade disc, A disc grinder according to claim 4, characterized in that the outer circumference (9) of the smaller blade disc (2) and the outer circumference of the deceleration groove (6) in the opposite blade disc (JJ) are axial,