CA2983614C

CA2983614C - Treatment fitting for the treatment of aqueously suspended fibrous material

Info

Publication number: CA2983614C
Application number: CA2983614A
Authority: CA
Inventors: Martin Schmid; Jutta HECHT
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2015-04-24
Filing date: 2016-02-22
Publication date: 2020-03-10
Anticipated expiration: 2036-02-22
Also published as: CN107530707B; CN109317253A; CA2983614A1; BR112017022574A2; EP3398683A1; KR20170139156A; EP3398682B1; DE102015207536A1; EP3285931A1; CN109317255A; CN109317254B; EP3398684A1; EP3398684B1; CN109317255B; WO2016169672A1; BR112017022574B1; CN109317253B; EP3398682A1; CN107530707A; EP3398683B1

Abstract

The invention relates to a method for producing a fitting (2,3) for the treatment of aqueously suspended fibrous material (1) in a treatment gap (4), consisting of a base body (5) with treatment elements (6) facing the gap (4). In this case, the expenditure on production shall be reduced by virtue of the fact that the treatment elements (6) are applied at least partly as a layered structure consisting of a liquid or solid material and are thereby subjected to a physical or chemical curing or melting process.

Description

TREATMENT FITTING FITTING FOR THE TREATMENT OF AQUEOUSLY
SUSPENDED FIBROUS MATERIAL
The invention comprises a fitting for the treatment of aqueously suspended fibrous material in a treatment gap bounded by two treatment surfaces rotating relative to each other about an axis of rotation and formed by fittings, comprising a base body with elongated treatment elements facing the gap and at least one directional component extending radially, produced by the method according to the invention.
Fittings of said type are intended to be suitable for the mechanical treatment of suspended fibrous material. This primarily means the refining of paper fibers, dispersion of contaminants and fibers and deflaking, that is to say the disintegration of fiber agglomerates.
Fittings are installed, for example, in refining machines - so-called refiners. The suspension in refiners has a solids content of about 2-8%.
Similar consistencies are also run in deflakers.
In machines for higher consistencies, reference is made, for example, to high consistency refiners, dispergers or kneaders.
The mechanical treatment taking place therein can cover the whole of the fibrous material, therefore also the dispersion of contraries contained therein.
Such machines have at least one rotor and at least one stator with either disk-like or wedge-like surfaces, to which the fittings are attached, so that gaps can be formed between them. Many fittings have webs and grooves on the working surfaces, for which reason mention is also made of "blade fittings". Other fittings have the shape of toothed rings.

-2-It is known that, in addition to the shape of such webs, grooves and teeth, the material of which they are composed also has effects on the processing of the fibrous material.
The fittings are subjected to wear and must therefore be replaced at specific intervals. In addition, the wear can lead to the processing action changing during the service life.
A considerable part of the operating costs which arise during the mechanical treatment of fibrous materials in the pulp and paper industry originates from the energy costs. Therefore, there have always been attempts to construct and operate fittings and the machines used in such a way that - measured by the desired success - an excessively high input of energy is not required.
It is therefore understandable that, for the development of fittings, a considerable amount of effort is expended, which is reflected in the configuration of the shape and in the selection of the material.
In order to reduce the expenditure on manufacture of the fittings, it is proposed, for example in DE 10 2004 016 661 Al, to assemble the fittings from a plurality of elements and then to weld or to braze these to one another.
It is known from FR 2 707 677 Al that the knife surface of the set is to be covered with an abrasive material by means of a laser.
The object of the invention is to widen the freedom of configuration in such fittings with economically tolerable outlay.

- 3 -Ac co r di ng to the invention, the object has been achieved in that the treatment elements are applied at least partly as layers of a liquid or solid material and are subjected to a physical or chemical curing or fusing process.
As a result of the application as layers, material and shape of the treatment elements can be adapted more simply and more comprehensively to the specific requirements.
It is advantageous if in each case a core of the treatment elements is connected in one piece to the base body, and at least one outer region, preferably the outer part of the treatment elements facing the treatment gap, is applied as layers of a liquid or solid material and is subjected to a physical or chemical curing or fusing process.
In this way, the treatment elements can be provided with a wear layer. If, here, the color of the core should differ from that of the outer part of the treatment elements, then conclusions can be drawn about reaching the wear limit via the color change.
In addition, the reconditioning of worn fittings is possible by the application of the wear layer.
The core of the treatment elements not only functions as a connecting element to the base body but also reduces the quantity of required and normally expensive, wear-resistant material.
However, should the arrangement and configuration of the treatment elements be given more freedom, it is advantageous if the treatment elements as a whole are applied as layers of a liquid or solid material and are subjected to a physical or chemical curing or fusing process.
This also permits the use of universally usable base bodies.

- 4 -Since the material applied as layers is normally expensive, in this way a cheaper, different material can be used in the base body.
Because of the high loading in such machines for refining, dispersing or deflaking fibrous materials, the material applied as layers should be powdery and/or comprise one or more metals or metal compounds.
Here, it is advantageous if the material applied as layers is sintered or fused by means of lasers.
Ceramic layers can also be produced in this way.
Furthermore, the surface roughness of the treatment element can be influenced by the grain size of the powder.
The production method according to the invention makes it possible to select materials in accordance with the specific requirements, for which reason at least part, preferably the whole, of the surface of the treatment elements respectively formed by two side surfaces and the upper side located in between and directed towards the gap should consist of a material which differs from the material of the base body. Thus, the treatment elements can be configured to be very wear-resistant with the minimal use of expensive materials such as tungsten carbide.
Because of the generally higher loading of the treatment elements with regard to the base body, at least the plurality, preferably all, of the treatment elements should in particular consist entirely of a material which differs from the material of the base body.

CA 02983614 2017-10-.23

- 5 -B y means of material selection, but in particular by means of the application as layers, it is possible to form at least the surface of the treatment elements that faces the gap in a profiled manner, which improves the fibrillation of the fibers.
It is advantageous if this profile of the upper side of the treatment elements is formed by recesses, which are bounded by webs extending between them and, at the edge of the upper side, also by webs forming part of the side surface of the treatment elements.
Because of the high stress on this profile during the rotation of the treatment surfaces and during the treatment of the fibrous material suspension, at least along a side surface of the treatment elements which preferably points in the direction of rotation in the case of a rotating treatment surface and points counter to the direction of rotation in the case of a stationary treatment surface (the other, rotating treatment surface), the webs should have a greater width than the webs extending between the recesses.
Comprehensive protection of the profile independently of the direction of notation can be ensured in that, along both side surfaces of the treatment elements, the webs which form a part of the side surfaces have a greater width than the webs extending between the recesses.
With regard to the production method preferred here, in the interests of simplification of the same, it has proven to be advantageous for at least the outer region of the treatment elements, lying below the profile, to be filled completely with the appropriate material over a thickness of at least 2 mm, preferably at least 4 mm, the density of this material in the sections with the PCl/EP2016/053640

- 6 -webs located above being higher than in sections with recesses located above.
This thus permits a flat application of the in particular powdery material as layers over the entire cross section of the treatment element, the applied material then being subjected to a fusing process, preferably by means of lasers, only or particularly intensively in the region of the webs.
Because of the small dimensions of the recesses and webs, in the region of normally substantially less than 1 mm, this is extremely simplifying for the production.
If the profile of the treatment elements is abraded as a result of wear, then material is also increasingly detached or washed out of the recesses, so that a specific profile depth remains ensured over a long operating period. The detached material is not critical to the fibrous material treatment process, because of the small quantity of material in relation to the quantity of fiber treated.
Alternatively or additionally, it can likewise be advantageous if the profile of the webs changes at least partly at right angles toward the upper side of the treatment elements. In this way, it is possible to implement recesses under the upper side of the treatment elements which are opened towards the upper side only with increasing wear. Therefore, permanent closure of the recesses via fibrous materials or fines can be countered effectively and the stability of the treatment elements can be increased.
In general, treatment machines for fibrous material preparation have circular or annular treatment surfaces which are assembled from a plurality of fittings. Here, the advantages of the production method according to the invention with regard to production feasibility and

- 7 -ec onomy manifest themselves, in particular when the base body has the shape of a circular segment or an annular segment and the product of segment angle (in ) and the circular diameter (in cm) is greater than 6000, preferably greater than 6500. The production process according to the invention permits larger fittings and thus reduces their number per treatment area, which improves the homogeneity of the treatment.
The circular diameter of the base body should lie between 35 and 150 cm.
As distinct from the previously usual casting of the fittings, the method according to the invention makes it possible to reduce the thickness of the base body and therefore also its material requirement and weight.
It has proven to be particularly advantageous that the thickness of the base body is lower than the height of the treatment elements and in particular makes up less than 85%, preferably less than 75%, of the height of the treatment elements.
When considering the thickness of the base body, locally limited thickenings, for example for fixing in the housing or the like, remain disregarded.
As a result of the deliberate use of very wear-resistant materials, the height of the treatment elements, starting from the base body, can be reduced with the same operating time, which in turn simplifies its application as layers. Added to this is a reduced idling power of the machine, a low height of the treatment elements being advantageous.
Therefore, the height of the treatment elements should at least partly, preferably wholly, lie below 5 mm, preferably below 4 mm.

- 8 -In order to intensify the treatment, the production method according to the invention, as distinct from the previously usual casting, permits very narrow treatment elements and likewise short distances between adjacent treatment elements. For this reason, the treatment elements should have an elongated cross-sectional shape parallel to the base surface and, at least partly, preferably wholly, have a width between 0.1 and 5 mm, in particular between 0.1 and 1 mm, and/or the distance between adjacent treatment elements should at least partly, preferably wholly, lie between 0.1 and 5 mm, in particular between 0.1 and 2 mm.
Furthermore, it is advantageous if the radius at the transition between base body and treatment element is less than 1 mm, preferably less than 0.3 mm, and the treatment elements can be implemented without any molding draft. This leads to a larger open useful surface, an improved conveying action of the fittings and to optimal utilization of the treatment area.
The method according to the invention now also permits undercuts in the treatment elements. Thus, for example, it may be advantageous for at least one side surface of the treatment elements to be inclined in relation to a normal to the direction of rotation of the treatment surface.
In order to produce a conveying action with regard to the fibrous material to be treated, in the case of a rotating treatment surface, the side surface of the treatment elements pointing in the direction of rotation should be inclined counter to the direction of rotation in relation to a normal to the direction of rotation.
In the interests of an optimal arrangement of the treatment elements, it is often advantageous if, at

- 9 -least in some sections, the elongated treatment elements extend non-rectilinearly, i.e. are curved or have a bend.
By means of the preferred production method, this is now also possible in conjunction with inclined side surfaces.
The invention is to be explained in more detail below by using a number of exemplary embodiments.
In the appended drawing:
Figure 1 shows a schematic cross section through a refining arrangement;
figure 2 shows a plan view of a fitting 2, 3 of the refining arrangement;
figures 3-6 show cross sections through different fittings 2, 3 and figures 7-9 show plan views of two different treatment elements 6.
In the housing of the refining arrangement, according to figure 1, a refining gap 4 is formed by a stationary refining surface coupled to the housing and a refining surface rotating about an axis of rotation 15.
The two annular refining surfaces (treatment surfaces) extend parallel to each other, the distance between these normally being adjustable.
The rotating refining surface here is moved in the direction of rotation by a shaft 16 rotatably mounted in the housing. This shaft 16 is driven by a drive, likewise present in the housing.
The fibrous suspension 1 to be refined in the example shown here reaches the refining gap 4 between the two refining surfaces via a feed through the center.
However, a feed via openings in the fitting is also possible.

- 10 -The fibrous suspension 1 passes the interacting refining surfaces radially toward the outside and leaves the adjacent annular chamber through a discharge.
Not illustrated are the means, known per se, with which a force is produced in order to press the two refining surfaces toward each other.
The two refining surfaces are each formed by a plurality of refining fittings 2, 3 in the form of circular segments or annular segments according to figure 2, which each extend over a circumferential segment of the corresponding refining surface.
In the circumferential direction beside one another in a row, the fittings 2 result in the stationary refining surface, and the other fittings 3 result in the rotating refining surface.
As shown in figure 2, the fittings 2, 3 are each formed by a base plate 5 having a multiplicity of bar-like treatment elements 6 extending substantially radially and grooves 9 located in between.
The cross section of the treatment elements 6, also called knives, is generally rectangular, as illustrated in figures 3, 4 and 6, but there are also other shapes.
Thus, according to figure 5a-c, one or both of the side surfaces 18 of the treatment elements 6, usually extending approximately at right angles to the direction of rotation 17 of the refining surface, can also be inclined in or counter to the direction of rotation 17. A delivery action in the refining gap 4 and therefore also an intensification of the fiber treatment is achieved if, as shown in figure 5a-c, in the case of a rotating refining surface the side

-11 -surface 18 of the treatment elements 6 that points in the direction of rotation 17, is inclined counter to the direction of rotation 17 in relation to a normal to the direction of rotation 17.
According to figure 5c, both sides of the treatment elements 6 are inclined in the same direction.
In order in particular to reinforce the upper region of the treatment elements 6 because of its high wear, according to figure 5a the side surface 18 that points counter to the direction of rotation 17 can be inclined counter to the direction of rotation 17 or, as in figure 5b, extend at right angles to the direction of rotation 17. However, the variation in the inclinations of the side surfaces 18 is not restricted thereto but can also be carried out depending on the intended action, for example even in the case of stationary refining surfaces.
Parallel to the base surface 5, the treatment elements 6 have an elongated cross-sectional shape, the upper side 19 of the treatment elements 6, facing the treatment gap 4, generally extending parallel to the outer surface of the base body 5.
For the purpose of optimizing the arrangement and its action, the treatment elements 6 frequently run non-rectilinearly, at least over a radial section, i.e. in a curve, in a wavy form or, as can be seen in figure 2, in a bent form.
This is now possible in conjunction with the following production method, even in the case of inclined side surfaces 18.
In order to reduce production costs of the fittings 2, 3, only the treatment elements 6 of the fittings are at least partly applied as layers of a liquid or solid material and thereby subjected to a physical or chemical curing or fusing process.

- 12 -Th i s means that the materials can be selected in accordance with the specific stresses and requirements.
Thus, in particular, the base body 5 can be cast from an inexpensive metal and have the same shape for differently configured fittings 2, 3. Even re-use of the base body 5 is possible.
Since the base body 5 is not subjected to any increased wear during operation, there are no specific requirements on its wear resistance either.
By contrast, the treatment elements 6 are subjected to increased wear, for which reason at least part of the surface of the treatment elements 6 respectively formed by two side surfaces 18 and the upper side 19 formed in between and directed toward the gap 4 consists of a wear-resistant material which differs from the material of the base body 5.
Because of the extremely high stress in machines for the treatment of fibrous material 1, the application as layers of powdery material, which comprises ceramic or one or more metals or metal compounds, is particularly suitable. This material applied as layers can then be sintered or fused by means of lasers after each layer.
In figure 3 and 5, the arrangement of the treatment elements 6 on the base body 5 can be chosen as required.
This is made possible by the fact that all the treatment elements 6 consist wholly of a material which differs from the material of the base body 5.
Therefore, the treatment elements 6 as a whole can be applied as layers of a liquid or solid material and be subjected to a physical or chemical curing or fusing process.

CA 02983614 2017-10-.23

- 13 -Differing from this, the treatment elements 6 in figure 4 and 6 each have a core 7 connected in one piece to the base body 5. Therefore, although the arrangement of the treatment elements 6 is predefined, on the other hand very strong fixing to the base body 5 is also ensured by the cores 7.
Accordingly, also only an outer region of the treatment elements 6 is applied as layers of a liquid or solid material and subjected to a physical or chemical curing or fusing process.
Whereas in figure 4 the complete surface of the treatment elements 6 is produced as layers, in figure 6 this is carried out only on the upper side 19 facing the treatment gap 4.
In this case, for example, tungsten carbide is suitable as an outer wear layer for the layered structure, a thickness of this wear layer of 1 mm normally being adequate.
Since the material applied as layers often differs in terms of color from the material of the base body 5, complete abrasion of the material applied as layers on the upper side 19 of the treatment elements 6 that points toward the gap 4 can easily be detected.
This primarily applies to the treatment elements 6 with core 7, which are particularly well suited to reconditioning of worn treatment elements 6.
In order to improve the fibrillation of the fibres, at least the upper side 19 of the treatment elements 6 that points toward the gap 4 can be configured so as to be profiled. This profile substantially comprises recesses 20 on the upper side 19, which are delimited via webs 21 extending between the recesses 20 and, at the edge of the upper side 19, also by webs 22 forming part of the side surface 18 of the treatment elements

- 14 -6. In figure 7 and 9, the recesses 20 are formed by slots open toward the gap 4 and, in figure 8, by open honeycombs.
Since the profile is subjected to high stress, in figure 8 the webs 22 along a side surface 18 of the treatment elements 6 have a greater width than the other webs 21, in particular those extending between the recesses 20.
The reinforced webs 21 are located on the side pointing in the direction of rotation 17 in the case of a rotating refining surface and, in the case of a stationary refining surface, on the side pointing counter to the direction of rotation 17 (the opposite, rotating refining surface).
Differing from this, in figure 7 the webs 22 along both side surfaces 18 of the treatment elements 6 have a greater width than the webs 21 extending between the recesses 20.
It is also important here that the outer region of the treatment elements 6, located under the profile, is filled completely with the appropriate material over a thickness of at least 4 mm, the density of this material in the sections with webs 21, 22 located above being higher than in sections with recesses 20 located above.
Whereas this density difference in figure 3b extends by way of example over a substantial part of the treatment element 6, in figure 6a it is to be found as far as the core 7.
This simplifies the production, since the powdery material for the treatment element 6 no longer has to be applied exactly only for the webs 21, 22 but can also come to lie in the region of the recess 20 located above in the direction of the gap 4.

- 15 -Howe ve r , the sintering of this material following the application of each layer is then carried out to the greatest extent only in the region of the webs 21, 22 located above in the direction of the gap. While the part of the material that is fused on is relatively hard and wear-resistant, the part of the material not treated or treated only slightly by the laser is porous. With increasing wear of the profile, this porous material is washed out, which leads to a deepening of the original recess 20. As a result, the fitting 2, 3 remains usable for substantially longer.
Figure 9 shows an embodiment in which the profile of the webs 21, 22 changes at right angles toward the upper side 19 of the treatment elements 6. With increasing abrasion of the profile as a result of wear, new recesses 20 are opened. In practical terms, the treatment elements 6 here consist of a plurality of layers arranged one above another toward the refining gap 4, the webs 21 of one layer extending substantially over the slot-like recesses 20 of the layer located underneath.
In this way, the action of the profile can be maintained over a long operating time.
Since the whole fitting 2, 3 is no longer cast, the thickness 11 of the base body 5 can be lower than the height 10 of the treatment elements 6, which has a positive effect on the weight and the ability to handle the fitting 2, 3. This in turn likewise permits the segment angle 8 of the fitting 2, 3 to be chosen to be greater than usual, so that the product of segment angle 8 (in ) and the circular diameter (in cm) is greater than 6000, preferably greater than 6500. Here, the circular diameter of the base body 5 lies between 35 and 150 cm.

- 16 -Fo r example, the height 10 of the treatment elements 6 is less than 5 mm here, the width 12 of the treatment elements 6 is between 0.1 and 1 mm, and the distance 13 between adjacent treatment elements 6 is between 0.1 and 2 mm.
The new production method additionally permits smaller radii 14 of less than 0.3 mm at the transition between base body 5 and treatment element 6, which is positive for the conveying action.

Claims

claims

1. A fitting (2, 3) for the treatment of aqueously suspended fibrous material (1) in a treatment nip (4) which is delimited by two treatment surfaces which rotate relative to one another and are formed by fittings (2, 3), consisting of a main body (5) with elongate treatment elements (6) which point towards the nip (4) and run radially with at least one directional component, the treatment elements (6) being applied at least partially in layers from a liquid or solid material and in the process being subjected to a physical or chemical hardening process or melting process, and at least part of the entire, surface of the treatment elements (6) which is formed in each case by two side faces (18) and the upper side (19) which lies in between and is directed towards the nip (4) consisting of a material which differs from the material of the main body (5), characterized in that at least the upper side (19) of the treatment elements (6) which points towards the nip (4) has a profile which is formed by cut-outs (20) which are delimited by webs (21) which run in between and are also delimited at the edge by webs (22) which form a part of the side face (18) of the treatment elements (6), the webs (22) having a greater width at least along a side face (18) of the treatment elements (6) than the webs (21) which run between the cut-outs (20).

2. The fitting as claimed in claim 1, characterized in that the treatment elements (6) consist entirely of a material which differs from the material of the main body (5).

3. The fitting as claimed in claim 1 or 2, characterized in that, at least along a side surface (18) of the treatment elements (6) which point in the direction of rotation (17) in the case of a rotating treatment surface and points counter to the direction of rotation (17) in the case of a stationary treatment surface, the webs (22) have a greater width than the webs (21) extending between the cut-outs (20).

4. The fitting as claimed in any one of claims 1 - 3, characterized in that, along both side surfaces (18) of the treatment elements (6), the webs (22) have a greater width than the webs (21) extending between the cut-outs (20).

5. The fitting as claimed in any one of claims 1 - 4, characterized in that an outer region of the treatment elements (6), lying below the profile, is filled completely with an appropriate material over a thickness of at least 2 mm, or at least 4 mm, the density of this material in the sections with the webs (21, 22) located above being higher than in sections with recesses (20) located above.

6. The fitting as claimed in any one of claims 1 - 5, characterized in that the profile of the webs (21, 22) changes at least partly at right angles toward the upper side (19) of the treatment elements (6).

7. The fitting as claimed in any one of claims 1 - 6, characterized in that the main body (5) has the shape of a circular segment or an annular segment and the product of segment angle (8) (in °) and the circular diameter (in cm) is greater than 6000, or greater than 6500.

8. The fitting as claimed in any one of claims 1 - 7, characterized in that the thickness (11) of the main body (5) is lower than the height (10) of the treatment elements (6).

9. The fitting as claimed in any one of claims 1 - 8, characterized in that the height (10) of the treatment elements (6) at least lies below 5 mm, or below 4 mm.

10. The fitting as claimed in any one of claims 1 - 9, characterized in that the elongated treatment elements (6) at least have a width (12) between 0.1 and 5 mm, or between 0.1 and 1 mm.

11. The fitting as claimed in any one of claims 1 - 10, characterized in that the radius (14) at the transition between the main body (5) and the treatment element (6) is less than 1 mm, or less than 0.3 mm.

12. The fitting as claimed in any one of claims 1 - 11, characterized in that at least one side surface (18) of the treatment elements (6) is inclined in relation to a normal to the direction of rotation (17) of a treatment surface.

13. The fitting as claimed in claim 12, characterized in that in the case of a rotating treatment surface, the side surface (18) of the treatment elements (6) pointing in the direction of rotation (17) is inclined counter to the direction of rotation (17) in relation to a normal to the direction of rotation (17).

14. The fitting as claimed in any one of claims 1 - 13, characterized in that, at least in some sections, the elongated treatment elements (6) extend non-rectilinearly.