EP1572366B1 - Method for producing fillings for mechanically processing paper pulp - Google Patents

Abstract

A method for fabricating fillings that are utilized in refiners for the purpose of refining paper fiber stock. The filling manufactured in accordance with the method of the present invention includes a base body, an overlay template on the base body and processing elements. The processing elements are inserted into the overlay template that is equipped with corresponding openings. A solid connection is subsequently produced, for example, by way of high temperature welding. Advantages of the method include the selection of optimum materials for the processing elements; the fabrication process is flexible; and the method is especially economical, when measured by the quality of the produced fillings.

Description

The invention relates to a method for producing sets according to claim 1.

Cloths produced in this way are primarily used to grind paper fibers, to disperse contaminants in the paper pulp or to remove debris, ie to dissolve paper fiber agglomerates. They are then used in grinding machines (refiners), de-spreaders or dispersers. Such machines have at least one rotor and at least one stator with either disc-shaped or conical surfaces on which the sets are mounted, so that gaps can form between them. Many trimmings have webs and grooves on the work surfaces, which is why we also speak of "knife trimmings". Other trimmings, for example as inserts in dispersers, have the form of toothed rings. In the DE 195 23 704 A1 Dispergergamituren are shown and described. It is known that in addition to the shape of the webs, grooves and teeth and the material of which they are made, has effects on the processing of the pulp.

In the mechanical processing by means of such trimmings, the paper fibers are in a pumpable suspension, ie with a solids content of about 2-8% before or as a tough substance with an overlying solids content. Dispersers usually work at a solids content between 15 and 25%.

The trimmings are subject to wear and must therefore be replaced at certain intervals. However, the wear can already lead to the fact that the machining effect changes. Shape, in particular edge shape, and surface of the trimmings namely have a paramount influence on the processing effect. These changes have the disadvantage that from a certain point in time with the same machine can no longer be optimally worked.

It is therefore understandable that considerable effort is devoted to the development of trimmings, which is reflected in the design of their shape and in the choice of material. It has been found that materials that are particularly suitable for the processing elements have properties that can be very problematic in their use for the body of the set. In particular, this relates to materials that are very hard and brittle and therefore do not have the necessary to the body toughness. Furthermore, such materials are relatively expensive and expensive to manufacture and can be compared to normal metallic materials process only with great effort.

The main body of a machining tool provides the connection of the processing elements to the other components, eg. As those of a grinding machine ago. Because of the high forces that occur in such a grinding machine, high strength requirements are placed on the body. It must also be possible to securely fasten it to the grinding machine, for example by highly stressed screws are required. Because of these requirements, a particularly strong and tough material is required.

From the DE 196 03 548 A1 A method for the production of sets is already known, in which these are assembled from separately produced parts. According to this publication, a high-temperature soldering process under vacuum can be used for this purpose. However, these methods, which are in themselves suitable, are complicated to carry out and do not always lead to sufficient strengths.

In the WO 99/37402 A1 Although a process for the production of Refinergamituren is described, with which it is indeed possible to choose a different material for the knife than for the base plate, but it is very complicated and complicated because of the large number of items that are to be assembled exactly.

From the US-A-681,270 Another method for the production of Mahlgarnituren is known. Again, the Mahlleisten be prepared separately, in a plate used and firmly connected with this by tack welding. To perform such a joining method, the grinding bars must be provided on its underside with fixing tongues which are inserted through the openings in the plate, after which they protrude on the underside of the plate, so that subsequently the welding process can be carried out.

The invention is based on the object to design the method for the production of trimmings so that the production is substantially simplified and yet particularly suitable hard materials for highly stressed

Machining elements can be used.

This object is achieved by the features mentioned in claim 1.

The mask used for the process may consist of a sheet of uniform thickness, in which the openings have been introduced by laser cutting. It is easily possible to make different openings for sets with different grinding effect as needed. Since the processing elements are initially manufactured separately, it is possible to use for these optimal materials and thereby to produce the shape of the set relatively easy. With the help of the mask namely, it is possible to position the processing elements precisely and safely in the right places on the base body and to keep it there during the subsequent operation. Since usually a larger number of processing elements is required for a set, it makes sense to perform the insertion of the elements in the mask by means of an automatically operating device. Not only does the process have the advantage of being readily operable and readily automatable, it also provides very good strength because the processing elements can be bonded to both the base and the mask. Particularly suitable for this purpose is a high-temperature soldering method with which all connections belonging to one processing unit can be produced simultaneously. Such processes are usually carried out at very high temperatures, e.g. above 1000 ° C, preferably about 1050 ° C. A protective gas atmosphere, e.g. Argon, use; A vacuum is also conceivable, but more complex.

The outline contour of the mask can be slightly smaller than that of the associated base body. It is also possible to associate several smaller masks with a single basic body by segmenting them in the circumferential direction. This simplifies the grinding technology design of diagonal knife sets: Since the knives of such sets are parallel to one another on a segment, the deviation of the knife angles from the desired value can be kept smaller with a larger number of segments per basic body. It is particularly economical, the body as

Form support frame, with bearing areas in which are also the holes for the mounting screws, which are required for mounting in the grinding machine. Such a support frame may be constructed of stacked laminations (sandwich construction); where the mounting holes already exist. The sandwich, the mask and the processing elements can be soldered together in a single operation.

In other cases, the mask can easily be attached to the main body, e.g. connect through welds.

The time-consuming processing of the hard structures on the processing elements can often be omitted since the precision of the sets thus produced is higher than e.g. in conventional, ie completely cast.

Fig. 1

Teil einer Mahlgarnitur im erfindungsgemäßen Herstellungsverfahren;

Fig. 2

Teil einer Mahlgarnitur nach Durchführung des erfindungsgemäßen Herstellungsvertahrens;

Fig. 3

eine besondere Form der Bearbeitungselemente;

Fig. 4

90°-Segment einer Mahlgarnitur für Scheibenrefiner;

Fig. 5

Mahlgarnitur im Schnitt mit speziellem Grundkörper;

Fig. 6

Teil eines mit einer Mahlgarnitur versehenen Kegelrefiners;

Fig. 7

Teil einer erfindungsgemäß hergestellten Disperger- oder Entstippergarnitur;

Fig. 8

eine Variante der in Fig. 7 gezeigten Garnitur.

The invention will be explained with reference to drawings. Showing:

Fig. 1

Part of a grinding set in the production process according to the invention;

Fig. 2

Part of a Mahlgarnitur after carrying out the manufacturing process according to the invention;

Fig. 3

a special form of the processing elements;

Fig. 4

90 ° segment of a refiner for disc refiner;

Fig. 5

Grinding set in section with special base body;

Fig. 6

Part of a provided with a Mahlgarnitur Kegelrefiners;

Fig. 7

Part of a Disperger- or Entstippergarnitur produced according to the invention;

Fig. 8

a variant of in Fig. 7 shown clothing.

Fig. 1 shows a part of a base 1, which is covered with a mask 3, wherein the connection is made here by welds 7 or welds. The mask 3 is provided with a larger number of through holes 4. In this case, a processing element 5 is already used in the leftmost opening. The processing elements 5 are strip-shaped and can be made, for example, from rolled profiles. They have a constant height over the surface, which therefore also corresponds to that of the foot 6. The openings 4 and the shape of the foot 6 are so each other matched that the processing element 5 can be used without play in the opening 4. Since a high-temperature soldering process is performed, the solder can already be applied prior to insertion on the corresponding surfaces. In this case, solder deposits in the form of small depressions or grooves in the components to be connected can advantageously be applied (not shown here).

The mask 3 can also be embedded in a correspondingly shaped base body, so be embedded.

The Fig. 2 , which shows a finished clothing 2 in perspective and in section, shows that the soldering surface 9 (drawn as thickened lines) connects the machining elements 5 both to the base body 1 and to the mask 3. Since the stress on the clothing during operation can be relatively high, this large-area connection is a particular advantage. The soldering surface 9 'extends here also over the contact surfaces between the mask 3 and body 1, but this is not always necessary and increases the processing cost. The thickness c of the mask 3 is usually between 2 and 10 mm in size. In the Fig. 2 partially shown garnish 2 can, for example, as a grinding segment (s. Fig. 4 ) be understood for a disc refiner, which is known to contain a plurality of strip-shaped processing elements 5. Such trimmings are also called knife trimmings. They are provided with screw holes 10 and are screwed onto the rotor or the stator of a Scheibenrefiners. As is known, these are wear parts, which must therefore be renewed at certain intervals.

Fig. 3 shows a way to make the shape of the processing elements 5 'special, which is facilitated by the inventive method. The example in the rotor in the direction of movement (arrow 18) forward cutting edge has at the top opposite the plane parallel to the direction of an angle α between 0 and 10 ° and at the front opposite the plane perpendicular thereto an angle γ also between 0 and 10 ° , This prevents unwanted edge rounding.

In the Fig. 5 the structure of a special embodiment of a set according to the invention is shown in section. It can be seen that the main body 1 " in the example shown here consists of three stacked laminations 19, 19 ', 19 ", each of which may have the same thickness (eg 6 mm) .The sheet-metal lamination 19 drawn above - by high-temperature soldering - with a lower plate 20 and this in turn with connected to the mask 3, which - as already described was provided with processing elements 5. The main body 1 "is not solid, but constructed as a support frame with bearing areas in which the screw holes 10 are located. Between the supporting areas cavities 21 are left free in the lamination plates 19, 19 ', 19 ", which saves weight and material costs.The lower plate 20 is dimensioned according to the strength requirements (possibly also the same thickness as the lamination plates 19, 19', 19"). ) and can absorb the pressure forces resulting from the grinding over the cavities 21. The laminations 19, 19 'and 19 "can be soldered to each other and to the lower plate 20 in the same operation, in which the processing elements 5 are anchored in the mask 3. The layered structure of the main body 1" has the particular advantage that its Making cheaper and cheaper. The outer contour, the cavities 21 and the screw holes 10 can be produced favorably by laser cutting.

It is also readily possible to use the method according to the invention if a set is to be manufactured for a cone refiner. Then the main body 1 '- like Fig. 6 shows - the shape of a truncated cone or a part thereof. This can also be provided with a mask 3, in which then in the manner already described, the processing elements 5 are inserted and secured. At the Fig. 6 It can also be seen that the sets made according to the method described can belong to both the rotor 11 and the stator 12. Most refiners are known to provide rotor and stator with knife sets. The slurry 14 to be ground is passed between the blades through the machine. The rotor 11 is driven by the shaft 13.

There are also applications in the field of dispersion and defibering of papermaking pulp, using liners provided with highly stressed tooth-shaped machining elements. Again, the inventive method can be used. So show the FIGS. 7 and 8 one each Base body 1 with an applied mask 3 and a number of already used processing elements. In this case, some different tooth shapes are exemplarily shown, for example, simple cubic teeth 15 or beveled teeth 16, which serve as processing elements in the context of the invention. It may be necessary to weigh whether a larger number of single-shaped, easy-to-manufacture single teeth is used or whether several teeth in larger or smaller groups of teeth 17, 17 'summarized and then to be used in the mask 3. The production of such a clothing is similar, as already described, ie the feet of the processing elements 5 ', ie the teeth or groups of teeth, and the openings in the mask 3 have approximately the same shape, so that an insertion of the processing elements 5' can take place. Subsequently, the final fixation of the processing elements with the mask 3 and the base body 1 takes place again.

As a material for the processing elements hard brittle metal alloys can be used that have been optimized for fiber processing. They can also be hardened after high temperature soldering or during the process. For example, after the high-temperature soldering, the cooling can be carried out so fast that, when carbon steels are used, the processing elements thermally harden.

The main body may consist of relatively tough Cr-Ni steel. As it is covered by the pulp suspension through mask and processing elements, it can also be made of non-corrosion resistant steel, further reducing costs. Another possibility is the coating of the base body with corrosion-resistant material.

The mask can be made with advantage from relatively tough Cr-Ni steel sheet, in which the openings were cut by laser.

Claims (22)

1. Method for producing fillings (2) for the mechanical treatment, in particular refining, of hydrated paper pulp, which are assembled from

   - at least one base body (1, 1', 1") and

   - at least one processing unit which is touched by the pulp material during the use of the fillings (2) in operation and which has a plurality of protrusions formed by processing elements (5, 5'),

   the following steps being carried out:
   the processing elements (5, 5') are produced separately,
   a mask (3) is produced, which is provided with penetrating openings (4), the shape of which corresponds to that of the foot (6) of the processing elements (5, 5'),
   the processing elements (5, 5') are inserted into the openings (4) in the mask (3),
   processing elements (5, 5') and mask (3) are connected firmly to one another by a high-temperature brazing method, and
   the mask (3) is connected to the base body (1, 1', 1").
2. Method according to Claim 1, characterized in that the firm connections of the processing elements (5, 5') to the mask (3) are produced by a method step in which the processing elements (5, 5') are also connected to the base body (1, 1', 1").
3. Method according to one of the preceding claims, characterized in that the high-temperature brazing method is carried out at a temperature above 1000°C.
4. Method according to Claim 3, characterized in that the high-temperature brazing method is carried out under vacuum or an inert gas atmosphere.
5. Method according to one of the preceding claims, characterized in that, by means of the operation in which processing elements (5, 5') and mask (3) are connected to one another, at the same time a connection of mask (3) and base body (1, 1', 1") at their contact surfaces is produced.
6. Method according to one of the preceding claims, characterized in that a base body (1") is produced which is configured as a supporting frame, having load-bearing regions in which screw holes (10) for fixing screws can be found.
7. Method according to Claim 6, characterized in that the base body (1") is constructed from layers lying one above another and connected to one another, in particular sheet metal laminations (19, 19', 19").
8. Method according to Claim 7, characterized in that the layers, in particular sheet metal laminations (19, 19', 19"), are brazed to one another, and in that this is carried out at the same time as the brazing of processing elements (5, 5') and mask (3).
9. Method according to one of the preceding claims, characterized in that the processing elements (5, 5') are hardened as they cool down after the high-temperature brazing.
10. Method according to one of the preceding claims, characterized in that the surfaces of the processing elements (5, 5') touched by the pulp during the use of the fillings (2) in operation are surface-treated during or immediately after the high-temperature brazing.
11. Method according to Claim 10, characterized in that the surface treatment increases the hardness and/or resistance to wear of the processing elements (5, 5').
12. Method according to Claim 10 or 11, characterized in that high-temperature brazing and surface treatment are carried out in the same oven.
13. Method according to one of the preceding claims, characterized in that processing elements (5, 5') and base body (1, 1', 1") are produced from different materials.
14. Method according to one of the preceding claims, characterized in that base body (1, 1', 1") and mask (3) are produced from materials of which the coefficients of thermal expansion are the same, with a tolerance of ±10%.
15. Method according to one of the preceding claims, characterized in that the mask (3) is produced from a sheet metal and in that the openings (4) are introduced by laser cutting.
16. Method according to Claim 15, characterized in that the external contour of the sheet metal is chosen such that it corresponds substantially to the external contour of the base body (1, 1', 1") .
17. Method according to Claim 15, characterized in that the mask (3) is embedded in the base body (1, 1',1").
18. Method according to one of the preceding claims, characterized in that the mask (3) is produced from a Cr-Ni-steel alloy.
19. Method according to one of the preceding claims, characterized in that the processing elements (5, 5') are strip-like elevations extending at right angles to the base body (1, 1', 1"), between which there are grooves (8).
20. Method according to Claim 19, characterized in that the projection of the strip-like elevations beyond the mask (3) is between 2 and 20 mm.
21. Method according to Claim 19 or 20, characterized in that the width of the strip-like elevations is between 2 and 30 mm, preferably 2 and 10 mm.
22. Method according to one of Claims 1 to 18, characterized in that the processing elements are teeth (15, 16) which extend at right angles to the base body (1, 1', 1").

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