Title of Invention

A METHOD FOR PRODUCING FITTINGS FOR MECHANICAL PROCESSING, IN PARTICULAR GRINDING OF WATER-CONTAINED PAPER STOCK

Abstract

The invention relates to the production of fttings, used e.g. in refiners for pulverising paper stock. The inventive accessory consists of a base body (1>, a mask (3) lying on said body, in addition to processing elements (5) which process the stock. The processing elements (5) e.g. strip-type blades are inserted into the mask (3), which is provided with corresponding cavities (4). A fixed bond is suhsequently produced, e.g. by a high—temperature soldering process. The advantage of said method is that optimal materials can be selected for the processing elements and that the production Method is flexible and particularly cost-effective in terms of quality of the produced fittings.

Full Text

The Invention relates to a method for producing fittings for the mechanical processing in particular grinding of water-containing paper stock. Fittings produced in this way can serve in particular for grinding paper fibre, dispersing impurities, in the paper stock or deflaking, thus dissolving paper stock agglomerates. They are then used in grinding machines (refiners), deflakers or dispersers. Such machines have at least one rotor and at least one stator with either discoid or conical surfaces to which the fittings are attached, so that gaps can form between them. Many fittings have lands and grooves on the working surfaces, giving rise to what are called "blade fittings*. Other fittings, example as inserts in dispensers, have the form of toothed rings. OE 195 23 704 Al discloses and describes disperser fittings. It is known that, in addition to the form of the lands, grooves and teeth, the material of which they are produced also has an effect on the processing of the fibre. With mechanical processing using such fittings, the paper fibres are present in a pumpable suspension, that is with a solids content of approximately 2-6%, or as tough material with a solids content in excess of this, Dispersers generally work at a solids content of between 15 and 25%. The fittings are subjected to wear and must therefore be replaced at certain intervals. But even before this the wear can also leed to the processing effect changing, for form, in particular edge form, and surface of the fittings have an overwhelming influence on the processing effect. The disadvantage of these changes is that from a certain point of time onwards it is no longer possble for the same machine to operate optimally. It is therefore understandable that considerable costs art incurred for tht development of fittings, which is reflected in the configuration of its form and in the choice of material. It has been shown that materials which are particularly well suited for processing elements have properties which can prove highly problematic when used for the base body of the fittings. In particular, this relates to materials which are very hard and brittle and therefore do not exhibit the toughness required for the base body. Further, such materials are relatively expensive and complex to produce and can be processed only at considerable expense, compared with normal metallic materials. The base body of a processing tool produces the connection of the processing elements to the other components, example those of a grinding machine. Due to the high forces occurring in such a grinding machine, high strength demands are made on the base body. It must also be possible to attach it securely to the grinding machine, for which example highly braced screws are required. Because of these demands, a particularly solid and tough material is required. DE 196 03 548 A1 discloses a process for producing fittings, in which these are assembled from separately produced parts. According to this publication a high- temperature soldering process can be used under vacuum for this purpose. These well-suited processes are, however, expensive to carry out and do not always result in adequate strength. WO 99/37402 Al describes a process for producing refiner fittings, with which although it is possible for a different material to be selected for the blades than for the base plate. It is very expensive and complicated due to the plurality of individual components which have to be fitted together precisely. The object of the invention is to configure the process for producing fittings such that their production is made substantially easier, and yet particularly suitable hard materials can be used for highly stressed processing elements. The object is achieved by the features of the invention. The mask used for the process may consist of a metal sheet of uniform thickness, in which the openings have been produced by later cutting. In this case, it is quite possible to produce different openings for fittings with a different grinding effect, as per requirements. The outline contour of the mask can be somewhat smaller than that of the associated base body. The mask can easily be connected to the base body, example by welding seams In other cases prior to inserting the elements. Since the processing elements are first produced separately, it is possible to use optimal materials for these and in the process to create the form of the fitting relatively easily. Using the mask, there is the possiblity of positioning the processing elements precisely and securely at the current places on the base body and keeping them there during the subsequent procedural step. Since a relatively large number of processing elements is as a rule required for a fitting, it is useful to carry out inserting the elements into the mask with the aid of an automatically operating device. The advantage of the process is not only rapid execution and good automation, but it also offers very good strength, because the processing elements can be connected both to the base body and also to the mask. A high-temperature soldering process is particularly well suited to this, with which all the connections belonging to a processing unit can be readily produced at the same time. Such processes are mostly performed at very high temperature, example over 1000°C, preferably approximately 1050°C. Then a protective gat atmosphere, example argon, is advantageously used; a vacuum is also conceivable, though more expensive. It is also possible to solder not only tht procesting elements and mask together,- but in the same procedural step also the mask to the base body, which results in greater strength of the entire fitting. The expensive processing of the hard structures on the processing elements can often be omitted, since the precision of the fittings produced in this way is greater than example in conventional fittings, that is fully cast ones. The invention will now be explained by means of the accompanying drawings, in which: Figure 1 shows part of a grinding fitting in the production process according to the invention; Figure 2 shows part of grinding fitting on completion of the production process according to the invention; Figure 3 shows a spectral form of the processing elements; Figure 4 shows a 90° segment of a grinding fitting for disc refiners; Figure 5 shows part of a cone refiner provided with a grinding fitting; Figure 6 shows part of a disperser or deflating fitting produced according to the invention; Figure 7 shows a variant of tht fitting illustrated in Figure 6. Figure 1 shows a part of a base body 1, fitted with a mask 3, the connection being produced here by welding seams 7. The mask 3 is provided with a relatively large number of continuous openings 4. A processing element 5 is already inserted into the opening shown on the far left. The processing elements 5 era strip-like and can produced axampla from roiled profiles. They have a surface which is constant over the height, which therefore also corresponds to that of the foot 6. The openings 4 and the form of the foot 6 match each other such that the processing element 5 can be inserted without play into the opening 4. In typical cases, in which a high-temperature soldering process is carried out, the solder can already have been applied to the corresponding surfaces prior to inserting. Deposits of solder in the form of small depressions or grooves can be produced advantageously in the components to be connected (not shown here). The mask 3 can also be inserted, thus embedded, into a correspondingly formed base body. Figure 2, which illustrates Finished fitting 2 both in perspective and in section, shows that the soldering surface 9 (illustrated as bold lines) connects the processing elements 5 both to the base body 1 and to the mask 3. Because the stress of the fitting during operation can be relatively high, this large-surface connection offers a particular advantage. The soldering surface 9, here also extends over the contact surfaces between mask 3 and base body 1, which is however not always required and increases processing costs. The thickness c of the mask 3 is as a rule between 2 and 10 mm. The fitting 2 partially shown in Figure 2 can example be understood as a grinding segment (see Figure 4) for a disc refiner, which is known to contain a plurality of strip-like processing elements 5. Such fittings are also known as blade fittings. They are provided with screw holes 10 and are screwed on to the rotor or the stator of the disc refiner. These are known to be wearing parts, which therefore have to be renewed at certain intervals. Figure 3 shows a possible way of specially shaping the form of the processing elements 5, made easier by the process according to the invention. On the upper surface opposite the plane parallel to the direction of motion the leading edge of cut example in the rotor in the direction of motion (arrow 18) has an angle a of between 0 and 10° and on the front side opposite the plane perpendicular thereto has an angle y likewise of between 0 and 10°. This avoids unwanted edge rounding. It is also readily possible to apply the process according to the invention if a fitting for a cone refiner is to be produced. Then the base body 1', as shown in Figure 5, has the form of a truncated cone or a part thereof. This too can be provided with a mask 3, into which the processing elements 5 are to be inserted and fixed in the above described manner. From Figure 5 it is also evident that the fittings produced according to the process described can belong both to the rotor 11 and to the stator 12. In most refiners it is known for rotor and stator to be provided with blade fittings. The suspension 14 to be ground ii fed in between the blades through the machine. The rotor 11 is driven by the shaft 13. There are also applications in the field of dispersing and deflating of paper stock in which fitting* are used which are provided with highly stressed toothed processing elements. Here too, the process according to tht invention can be applied. Figures 6 and 7 accordingly each show a base body 1 with a mask 3 placed thereon and a number of already inserted processing elements. Several different tooth forms an illustrated by way of example, example single cubic teeth 15 of chamfered teeth 16, which act as processing elements in the context of the invention. It should optionally be weighed up as to whether a relatively large number of simply formed, easy-to-produce individual teeth is used, or whether several teeth are to be combined into larger or smaller teeth groups 17, 17' and then inserted into the mask 3. The production of such a fitting is similar, as already described, that is the feet of the processing elements 5', thus the teeth or teeth groups, and the openings in the mask 3 have approximately the same form, so that the processing elements 5' can be inserted. Next again comes the final fixing of the processing elements with the mask 3 and the base bodyl. Hard brittle metal alloys which have been optimized for fibre processing can be used as material for the processing elements. They can also be hardened either after the high-temperature soldering or during that process. For example, after high-temperature soldering cooling can be performed so rapidly that the processing elements harden thermally with use of carbon steels. The base body may be made of relatively tough Cr-Ni steel. S9ince it is covered up to the paper stock suspension by the mask and processing elements, it can also be made of non-corrosion resistance steel farther reducing costs. A further possibility is the coating of the base body with corrosion-resistant material. The mask can be produced advantageously from relatively tough Cr-Ni steel sheet, in which the openings have been produced by laser cutting. We Claim 1. A method for producing fittings (2) for mechanical processing, in particular grinding, of water-containing paper stock in a device, the device comprises: - at least one base body (1,1) and - at least one processing means contacted by the paper stock material during operational use of the fitting (2), which has a plurality of protrusions formed from processing elements (5,50, the method comprising: • separately producing the processing elements (5,5; - producing a mask (3) with openings (4), the configuration of which corresponds to that of the foot (6) of the processing elements (5, 50; - connecting the mask (3) to the base body (1,10; - inserting the processing elements (5, 50 into the openings (4) of the mask (3); and - firmly connecting the processing elements (5, 50 and the mask (3) to one another. 2. A method as claimed in claim 1, wherein the openings (4) are continuous. 3. A method as claimed in claim 2, wherein the step of firmly connecting the processing elements (5, 5) with the mask (3) comprising additionally connecting the processing elements (5,5) to the base body (1,1). 4. A method as claimed in claim 1, 2 or 3, wherein the fixed connections are produced by a high-temperature soldering process. 5. A method as claimed in claim 4, wherein the high-temperature soldering process is carried out at a temperature above 1000°C. 6. A method as claimed in claim 4 or 5, wherein the high-temperature soldering process is carried out under vacuum or inert gas atmosphere. 7. A method as claimed in one of the preceding claims, wherein a connection of mask (3) and tha has body (1, 1) on their contact surfaca is produced by connecting the processing elements (5, 5) and the mask (3) to one another. 8. A method as claimed in claim 1, 2 or 3, wherein the solid connections of the processing elements (5,51) are produced by welding. 9. A method as claimed in one of claims 4 to 8, wherein the processing elements (5, 50 are hardened during cooling after the high-temperature soldering. 10.A method as claimed in one of claims 4 to 7, wherein the surfaces of the processing elements (5, 5) contacted during operational use of the fitting (2) by the water-containing paper stock are surface-treated either during or immediately after the high-temperature soldering. 11. A method as claimed in claim 10, wherein the surface treatment increases the hardness and/or wear resistance of the processing elements (5,50- 12.A method as claimed in claim 10 or 11, wherein the high-temperature soldering and surface treatment are carried out in the same oven. 13.A method as claimed in one of the preceding claims, wherein the processing elements (5, 5) and the base body (1,10 are produced from different materials. 14.A method as claimed in one of the preceding claims, wherein the base body (1, 10 and the mask (3) are made of materials, the heat expansion coefficients of which are equal to a tolerance of ±10%. 15. A method as claimed In one of the preceding claims, wherein the mask (3) is produced from a metal sheet and wherein the openings (4) are produced by laser cutting. 16.A method as claimed in claim 15, wherein the outer contour of the metal sheet is selected such that is corresponds substantially to the outer contour of the base body (1,1) 17.A method as claimed in claim 15, wherein the mask (3) is embedded in the base body (1,1). 18. A method as claimed in one of the preceding claims, wherein the mask (3) is made from a Cr-Ni steel alloy. 19.A method as claimed in one of the preceding claims, wherein the processing elements (5,5) are strip-like elevations extending vertically to the base body (1,1), between which elevations grooves (8) are located. 20. A method as claimed in claim 19, wherein the projection of the strip-like elevations over the mask (3) is between 2 and 20 mm. 21. A method as claimed in claim 19 or 20, wherein the width of the strip-like elevations is between 2 and 30 mm, preferably 2 and 10 mm. 22.A method as claimed in one of claims 1 to 19, wherein the processing elements are teeth (15,16) which extend vertically to the base body (1, n. The invention relates to the production of fttings, used e.g. in refiners for pulverising paper stock. The inventive accessory consists of a base body (1>, a mask (3) lying on said body, in addition to processing elements (5) which process the stock. The processing elements (5) e.g. strip-type blades are inserted into the mask (3), which is provided with corresponding cavities (4). A fixed bond is suhsequently produced, e.g. by a high—temperature soldering process. The advantage of said method is that optimal materials can be selected for the processing elements and that the production Method is flexible and particularly cost-effective in terms of quality of the produced fittings.

Documents:

1119-kolnp-2005-granted-abstract.pdf

1119-kolnp-2005-granted-claims.pdf

1119-kolnp-2005-granted-correspondence.pdf

1119-kolnp-2005-granted-description (complete).pdf

1119-kolnp-2005-granted-drawings.pdf

1119-kolnp-2005-granted-examination report.pdf

1119-kolnp-2005-granted-form 1.pdf

1119-kolnp-2005-granted-form 18.pdf

1119-kolnp-2005-granted-form 2.pdf

1119-kolnp-2005-granted-form 26.pdf

1119-kolnp-2005-granted-form 3.pdf

1119-kolnp-2005-granted-form 5.pdf

1119-kolnp-2005-granted-reply to examination report.pdf

1119-kolnp-2005-granted-specification.pdf

1119-kolnp-2005-granted-translated copy of priority document.pdf