GRINDING SET SEGMENT

Description

[0001] The invention relates to a clothing segment for refining aqueously suspended fiber material in a refining gap defined by two treatment surfaces rotating relative to one another and formed by clothing segments, comprising a base body with elongated treatment elements facing the refining gap and extending radially in at least one directional component, and grooves extending therebetween.

[0002] The invention also comprises a treatment surface consisting of several adjacently arranged, inventive clothing segments and a method for producing a clothing segment according to the invention for refining aqueously suspended fiber material in a refining gap, consisting of a base body with treatment elements facing the refining gap.

[0003] Such fillings have been known for a long time and are installed in grinding machines, so-called refiners. The suspension in refiners has a solids content of approximately 2-8%.

[0004] Such machines generally have at least one rotor and at least one stator with either disc-shaped or conical treatment surfaces, on which the dressings are mounted, allowing grinding gaps to form between them. The dressings have ribs and grooves on the treatment surfaces, which is why they are also referred to as "knife dressings."

[0005] The fittings are subject to high wear and therefore must be replaced at regular intervals. Wear can also lead to changes in the machining effect over their service life.

[0006] A significant portion of the operating costs incurred in the mechanical treatment of fibers in the pulp and paper industry stem from energy costs. Therefore, it has always been a goal to construct and operate fillings and the machines used in such a way that—relative to the desired result—the energy consumption is not excessive.

[0007] It is therefore understandable that considerable effort is put into the development of sets, which is reflected in the design of their shape and the choice of material.

[0008] In order to reduce the manufacturing costs of the fittings, DE 10 2004 016 661 A1, for example, proposes assembling the fittings from several elements and then welding or soldering them together.

[0009] The object of the invention is to extend the service life of such garnish segments while ensuring the most efficient grinding possible.

[0010] According to the invention, the object was achieved in that a plurality of channels are arranged in the base body, which channels run radially with at least one directional component and at least approximately parallel to the grinding gap and each have different distances from the grinding gap, which channels at least partially overlap one another or the groove base when viewed in the direction of rotation.

[0011] If wear and tear completely erodes the treatment elements during operation, this simultaneously leads to the opening of the channels, which partially overlap with the groove base in the direction of rotation. The removal of the wall of these channels facing the grinding gap causes these channels to now function as a groove, and the area between the opened channels to function as a treatment element.

[0012] Therefore, the width of the channels should essentially correspond to the width of the grooves and / or the width of the wall between adjacent channels in the direction of rotation should essentially correspond to the width of the treatment elements.

[0013] Furthermore, the channels should each run at least approximately parallel to at least one elongated treatment element located axially above them.

[0014] A slight inclination of the channels toward the grinding gap can also be advantageous. If the channels are inclined radially outward toward the grinding gap, the outer channels will open first when wear occurs.

[0015] This ensures that even with increasing wear, a sufficiently large open groove area and the required cutting edge length of the treatment elements are available.

[0016] Ideally, the design and / or arrangement of the channels of the treatment area, the clothing segment or a zone thereof is selected such that the open area of the grooves and / or the cutting edge length remains approximately the same throughout the entire service life, so that the idle power also remains approximately the same throughout the entire service life.

[0017] To achieve this, it can be advantageous if the groove bases of adjacent grooves are at different depths. Advantageously, the adjacent grooves are at different depths not only in the initial state but also during wear.

[0018] For this purpose, it has proven to be advantageous from a design perspective if the base body has several planes lying one above the other and at least approximately parallel to the grinding gap, each plane having several channels.

[0019] The channels of adjacent levels should be offset from each other in the direction of rotation in such a way that they partially overlap when viewed in the direction of rotation.

[0020] Irrespective of this, in the interest of homogeneous grinding, the grooves should at least predominantly have a constant width and / or the width of the treatment elements should at least predominantly be the same size.

[0021] For intensive grinding, it is advantageous if the width of the treatment elements is between 0.1 and 1.5 mm and / or the height of the treatment elements is less than 5 mm.

[0022] In order to optimise their arrangement and their effect, the elongated treatment elements and the channels are advantageously uneven, at least in sections.

[0023] The treatment areas, which are usually circular or ring-shaped, are usually composed of several segments. The diameter of the base body should be between 35 and 150 cm.

[0024] To ensure a sufficiently large number of grooves and treatment elements are available for every wear condition of the treatment surface, it may be advantageous to arrange and / or design the channels of adjacent clothing segments differently so that a sufficiently large number of channels are open for every wear condition. Furthermore, this allows the average number and the total width of the treatment elements to be kept constant.

[0025] For this purpose, it can be advantageous if at least some of the channel planes of at least two adjacent set segments are at different distances from the grinding gap.

[0026] With regard to the method for producing the clothing segments according to the invention, it is essential that the treatment elements, at least partially, preferably completely, and advantageously also the base body, are applied in layers from one or more liquid and / or pasty and / or solid materials and are subjected to a physical or chemical hardening or melting process. This hardening or melting process also includes sintering.

[0027] By applying the material in layers, the material and shape of the treatment elements and channels can be adapted more easily and comprehensively to the specific requirements.

[0028] It should be noted that depending on the material applied and the specific curing or melting process, shrinkage of up to 30% may occur.

[0029] Due to the high load in such machines for grinding fiber materials, the material applied in layers should be in powder form and / or contain one or more metals or metal compounds.

[0030] It is advantageous if the material applied in layers is sintered or fused using a laser.

[0031] Ceramic layers can also be produced in this way.

[0032] In addition, the grain size of the powder can influence the surface roughness of the treatment element.

[0033] In order to intensify the treatment, the manufacturing process according to the invention, in contrast to the previously conventional casting, allows very narrow treatment elements and equally small distances between adjacent treatment elements.

[0034] The invention will be explained in more detail below using an exemplary embodiment. The accompanying drawing shows: Figure 1 : a schematic cross-section through a grinding arrangement; Figure 2 : a plan view of a set segment 2 of the grinding arrangement; Figure 3 : a partial cross-section through two adjacent set segments 2 and Figure 4 : a partial cross-section through another set segment 2.

[0035] In the housing of the grinding assembly, Figure 1 a grinding gap 3 is formed by a fixed grinding surface coupled to the housing and a grinding surface rotating about a rotation axis 10.

[0036] The two circular grinding surfaces (treatment surfaces) run parallel to each other, and the distance between them is usually adjustable. In addition to the flat treatment surfaces shown here, conical treatment surfaces are also possible.

[0037] The rotating grinding surface is moved in the direction of rotation by a shaft mounted on a rotatable bearing in the housing. This shaft is driven by a drive, for example, also located in the housing.

[0038] In the example shown, the fiber suspension 1 to be ground enters the grinding gap 3 between the two grinding surfaces via an inlet through the center. However, feeding through openings in the grinding surface is also possible.

[0039] The fiber suspension 1 passes the interacting grinding surfaces radially outwards and leaves the adjoining annular space through an outlet.

[0040] Not shown are the known means by which a force is generated to press the two grinding surfaces against each other.

[0041] Both grinding surfaces are each formed by several circular segment or circular ring segment shaped grinding set segments 2 according to Figure 2which each extend over a circumferential segment of the corresponding grinding surface and are arranged next to one another in the circumferential direction.

[0042] The clothing segments 2 are, as in Figure 2 shown, each formed by a base plate 4 with a plurality of substantially radially extending, strip-shaped treatment elements 5 and grooves 6 therebetween.

[0043] Parallel to the base surface 4, the treatment elements 5 have an elongated cross-sectional shape, wherein the upper side of the treatment elements 5 facing the treatment gap 3 generally runs parallel to the outer surface of the base body 4.

[0044] In order to optimise their arrangement and their effect, the treatment elements 5 often run unevenly, i.e. curved, wavy or as in Figure 2 to see bent.

[0045] In order to reduce the manufacturing costs of the clothing segments 2, the base body 4 and the treatment elements 5 of the clothing segments 2 are applied completely in layers from a liquid, pasty or solid material and are subjected to a physical or chemical hardening or melting process.

[0046] This means that the materials can be selected according to the specific demands and requirements.

[0047] Due to the extremely high stresses encountered in machines for processing fibers, the layer-by-layer application of powdered material containing ceramics or one or more metals or metal compounds is particularly suitable. This layer-by-layer application of this material can then be laser sintered or fused after each layer, or bonded with a binder in a first step and later sintered (binder jetting process). In the latter process, the binder evaporates.

[0048] The arrangement of the treatment elements 5 on the base body 4 can be selected as required.

[0049] The circular diameter of the base body 4 is between 35 and 150 cm.

[0050] As in Figure 3As shown, a plurality of channels 8 are arranged in the base body 4, which channels run at least with one directional component radially and parallel to the grinding gap 3 and are each at different distances from the grinding gap 3, which channels partially overlap one another or with the groove base when viewed in the direction of rotation 11.

[0051] The production of this base body 4 is made considerably easier by applying it in layers.

[0052] If, as a result of wear during the grinding treatment, the treatment elements 5 are completely removed, this leads to the opening of the channels 8 closest to the grinding gap 3 due to the overlap with the groove base. This in turn has the consequence that the opened channels 8 now function as the groove 6 and the wall 9 between the opened channels 8 functions as the treatment element 5.

[0053] If the wall 9 between these first opened channels 8 is also removed, further channels 8 are opened due to the mutual, partial overlap, the wall 8 of which takes over the function of the treatment elements 5.

[0054] In order to ensure consistent treatment of the fiber material 1 even with increasing wear, the channels 8 should each run at least approximately parallel to an elongated treatment element 5 located axially approximately above them.

[0055] A slight inclination of the channels 8 towards the grinding gap 3, particularly radially outwards, can be advantageous for the flow.

[0056] In the interest of safe, homogeneous, and efficient grinding, the grooves 6 have at least a predominantly constant width. The width of the treatment elements 5 also remains at least predominantly the same in the radial direction.

[0057] In order to ensure this even when the channels 8 or their walls 9 assume their function, the width of the channels 8 essentially corresponds to the width of the grooves 6 and the width of the wall 9 between channels 8 adjacent in the direction of rotation 11 essentially corresponds to the width of the treatment elements 5.

[0058] To ensure the highest and most constant number of open channels 8 during wear of the base body 4, the base body 4 has several superimposed planes 7 parallel to the grinding gap 3, each with several channels 8. Figure 3 The planes 7 shown run through the axial center of the channels 8.

[0059] The channels 8 of adjacent planes 7 are arranged offset from one another in the direction of rotation 11. Furthermore, the channels 8 of adjacent planes 7 partially overlap in the direction of rotation 11, so that when a wall 9 is completely removed, the adjacent channel 8 located axially below it is opened.

[0060] The height of the treatment elements 5 is, for example, less than 3 mm and the width of the treatment elements 5 is between 0.1 and 1 mm.

[0061] In order to ensure that the open groove surface and the cutting edge length of the treatment elements 5 are as uniform as possible under any wear condition, it may be helpful to Figure 3 to see, the channels 8 of adjacent fitting segments 2 are arranged differently and designed differently.

[0062] Thus, as shown there, at least part of the planes 7 of two adjacent set segments 2 can be at different distances from the grinding gap 3.

[0063] Additionally or alternatively, the cross-sections of the channels 8 of adjacent fitting segments 2 may also differ. While the channels 8 of one fitting segment 2 are circular, the channels 8 of the adjacent fitting segment 2 have, for example, an elliptical cross-section.

[0064] Furthermore, it is of course also possible for the fitting segments 2 themselves to have differently designed zones, wherein the channels 8 of these zones are arranged differently and / or designed differently.

[0065] In addition, Figure 2 Feed channels 12, which extend radially outwards into the grinding surface and, due to the absence of treatment elements 5, support the feed of fiber suspension 1 into the grinding gap 3.

[0066] In contrast, Figure 4 8 axially offset channels with a rectangular cross-section. Here, too, the goal is to ensure a consistent open groove area and cutting edge length under all wear conditions.

[0067] It is important that the adjacent grooves 6 have different depths in the initial state and during wear.

Claims

1. Plate segment (2) for refining aqueously suspended fibrous material (1) in a refining gap (3) delimited by two treatment surfaces rotating relative to each other and formed by plate segments (2), consisting of a basic body (4) with elongate treatment elements (5) which face the refining gap (3) and run radially at least with one directional component and with grooves (6) running in-between, characterized in that a multiplicity of channels (8) running at least with one directional component radially and at least approximately parallel to the refining gap (3) and being at different distances from the refining gap (3) are arranged in the basic body (4), said channels at least partially overlapping one another or with the groove base in the direction of rotation (11).

2. Plate segment (2) according to Claim 1, characterized in that in the basic body (4) there are a plurality of planes (7) which lie one above another and are at least approximately parallel to the refining gap (3) and each have a plurality of channels (8).

3. Plate segment (2) according to Claim 1 or 2, characterized in that the grooves (6) have at least predominantly a constant width.

4. Plate segment (2) according to one of the preceding claims, characterized in that the width of the channels (8) substantially corresponds to the width of the grooves (6).

5. Plate segment (2) according to one of the preceding claims, characterized in that the width of the treatment elements (5) is at least predominantly the same size.

6. Plate segment (2) according to one of the preceding claims, characterized in that the width of the wall (9) between channels (8) which are adjacent in the direction of rotation (11) substantially corresponds to the width of the treatment elements (5).

7. Plate segment (2) according to one of Claims 2 to 6, characterized in that the channels (8) of adjacent planes (7) run offset with respect to one another in the direction of rotation (11) in such a manner that they partially overlap in the direction of rotation (11).

8. Plate segment (2) according to one of the preceding claims, characterized in that the width of the treatment elements (5) is between 0.1 and 1.5 mm and / or the height of the treatment elements (5) is less than 5 mm.

9. Plate segment (2) according to one of the preceding claims, characterized in that the depth of adjacent grooves (6) differs.

10. Plate segment (2) according to one of the preceding claims, characterized in that the elongate treatment elements (5) and the channels (8) run unevenly at least in sections.

11. Plate segment (2) according to one of the preceding claims, characterized in that the channels (8) each run parallel to at least one elongate treatment element (5) lying axially approximately thereabove.

12. Plate segment (2) according to one of the preceding claims, characterized in that the channels (8) are configured and / or arranged in such a manner that the open surface and / or the cutting edge length is approximately constant during the wear throughout the entire service life.

13. Plate segment (2) according to one of the preceding claims, characterized in that the channels (8) are slightly inclined toward the refining gap (3) in particular radially outward.

14. Treatment surface consisting of a plurality of plate segments (2) arranged next to one another configured according to one of the preceding claims, characterized in that the channels (8) of adjacent plate segments (2) are arranged and / or configured differently.

15. Treatment surface consisting of a plurality of plate segments (2) arranged next to one another configured according to one of Claims 2 to 14, characterized in that at least a part of the planes (7) of at least two adjacent plate segments (2) are at differing distances from the refining gap (3).