Patent Application
20210381164
The present invention relates to refiners, and, more particularly, to plate segments of refiners.
The present invention relates to a plate segment for refining aqueously suspended fibrous material in a refining gap delimited by two treatment surfaces rotating relative to each other and formed by plate segments, including a basic body with elongate treatment elements which face the refining gap and run radially at least with one directional component and with grooves running in-between.
The present invention also relates to a treatment surface including a plurality of plate segments arranged next to one another, and a method for producing a plate segment for refining aqueously suspended fibrous material in a refining gap, including a basic body with treatment elements facing the refining gap.
Plates of this type have been known for a long time and are installed in refining machines—what are called refiners. The slurry in refiners has a solids content of approximately 2-8%.
Such machines generally have at least one rotor and at least one stator with either disk-shaped or conical treatment surfaces on which the plates are attached such that refining gaps can be formed between them. The plates have webs and grooves on the treatment surfaces, and therefore “blade plates” are also talked of.
The plates are subject to a high degree of wear and therefore have to be replaced at certain intervals. The wear can also lead during the service life to the processing action changing.
A considerable portion of the operating costs that arise during the mechanical treatment of fibrous materials in the pulp and paper industry comes from the energy costs. It has therefore always been endeavored to construct and to operate plates and the machines used to the effect that a not too high use of energy is required, as measured by the desired success.
It is therefore understandable that a considerable outlay is expended on the development of plates, this being reflected in the configuration of the shape of the plates and in the selection of the material.
In order to reduce the outlay on production of the plates, it is proposed, for example in DE 10 2004 016 661 A1, to assemble the plates from a plurality of elements and then to weld or to braze them to one another.
What is needed in the art is to extend the service life of such plate segments with the refining being as efficient as possible.
The present invention provides a multiplicity of channels running at least with one directional component radially and at least approximately parallel to the refining gap and each being at different distances from the refining gap that are arranged in the basic body, said channels at least partially overlapping one another or with the groove base, as viewed in the direction of rotation.
If, during the operation, complete abrasion of the treatment elements occurs as a consequence of wear, this leads at the same time to the opening of the channels which partially overlap with the groove base in the direction of rotation. The abrasion of the wall of said channels that faces the refining gap leads to said channels now acting as a groove and to the surface lying between the opened channels acting as a treatment element.
Therefore, the width of the channels should substantially correspond to the width of the grooves, and/or the width of the wall between channels which are adjacent in the direction of rotation should substantially correspond to the width of the treatment elements.
Furthermore, the channels should each run at least approximately parallel to at least one elongate treatment element lying axially somewhat thereabove.
A slight inclination of the channels toward the refining gap may also be advantageous. If the channels are inclined radially outward toward the refining gap, the channels first of all open radially on the outside in the event of wear.
It is thereby ensured that, even if the wear increases, there is a sufficiently large open groove surface and the required cutting edge length of the treatment elements.
Ideally, the configuration and/or arrangement of the channels of the treatment surface, of the plate segment or of one zone thereof is selected in such a manner that the open surface of the grooves and/or the cutting edge length remains approximately identical throughout the entire service life, and therefore even the no-load power remains approximately the same throughout the entire service life.
In order to achieve this, it can be advantageous if the groove base of adjacent grooves differs in depth. The adjacent grooves here advantageously differ in depth not only in the starting state, but also during the wear.
For this purpose, it has proven advantageous structurally if in the basic body there are a plurality of planes which lie one above another and are at least approximately parallel to the refining gap and each has a plurality of channels.
The channels of adjacent planes should run offset with respect to one another here in the direction of rotation in such a manner that they partially overlap, as viewed in the direction of rotation.
Irrespective thereof, for homogeneous refining, the grooves should have at least predominantly a constant width, and/or the width of the treatment elements should be at least predominantly the same size.
For an intensive refining, 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.
For the purpose of optimizing their arrangement and their effect, the elongate treatment elements and the channels advantageously run unevenly at least in sections.
The generally circular or circular-ring-shaped treatment surfaces are generally composed of a plurality of plate segments. The circle diameter of the basic body here should be between 35 and 150 cm.
In order to have available a sufficiently large number of grooves and treatment elements during each state of wear of the treatment surface, it can be advantageous to arrange and/or to configure the channels of adjacent plate segments differently, and therefore a sufficiently large number of channels is opened for each state of wear. In addition, the average number and the cumulated width of the treatment elements can thus be kept constant.
For this purpose, it can be advantageous if at least some of the channel planes of at least two adjacent plate segments are at differing distances from the refining gap.
With regard to the method for producing the plate segments according to the present invention, it is essential that the treatment elements are at least partially, optionally completely, and, advantageously also the basic body is at least partially, applied layer by layer from one or more liquid and/or pasty and/or solid materials and, in the process, are subject to a physical or chemical hardening or melting process. Sintering is also included by said hardening or melting process.
The application layer by layer enables material and shape of the treatment elements and of the channels to be more simply and comprehensively adapted to the specific requirements.
It has to be noted here that a shrinkage of up to 30% may occur depending on the applied material and the specific hardening or melting process.
Due to the high loading in machines of this type for refining fibrous materials, the material applied layer by layer should be pulverulent and/or should include one or more metals or metal compounds.
It is advantageous here if the material which is applied layer by layer is sintered or melted by way of a laser.
Ceramic layers can also be produced in this manner.
Furthermore, the surface roughness of the treatment element can be influenced by the grain size of the powder.
To intensify the treatment, the production method according to the invention, in contrast to the previously conventional casting, permits very narrow treatment elements and equally small distances between adjacent treatment elements.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring now to the drawings, according to
The two circular-ring-shaped refining surfaces (treatment surfaces) run parallel to each other here, with the distance between them generally being adjustable. In addition to the flat treatment surfaces shown here, conical treatment surfaces are also possible.
The rotating refining surface is moved in the direction of rotation by a shaft which is mounted rotatably in the housing. Said shaft is driven by a drive which, by way of example, is likewise present in the housing.
In the example shown, the fibrous slurry 1 to be refined passes via an inlet through the center into the refining gap 3 between the two refining surfaces. However, feeding via openings in the refining surface is also possible.
The fibrous slurry 1 passes the interacting refining surfaces radially outward and leaves the adjoining annular space through an outlet.
The ways which are known per se and with which a force is generated in order to press the two refining surfaces against each other are not illustrated.
The two refining surfaces are each formed by a plurality of refiner plate segments 2 which, according to
As shown in
Parallel to the base surface 4 the treatment elements 5 have an elongate cross-sectional shape, with the upper side of the treatment elements 5 that faces the treatment gap 3 generally running parallel to the outer surface of the basic body 4.
For the purpose of optimizing their arrangement and their effect, the treatment elements 5 frequently run unevenly, i.e. in a curved, corrugated or, as can be seen in
In order to reduce the production costs of the plate segments 2, the basic body 4 and the treatment elements 5 of the plate segments 2 are completely applied layer by layer from a liquid, pasty or solid material and, in the process, subjected to a physical or chemical hardening or melting process.
This means that the materials can be selected in accordance with the specific stresses and requirements.
Due to the extremely high stress in machines for treating fibrous material 1, the application layer by layer of pulverulent material which includes ceramic or one or more metals or metal compounds is particularly suitable. Said material applied layer by layer can then be sintered or melted by way of laser after each layer or, in a first step, adhesively bonded with binder and sintered later (binder jetting method). In the latter method, the binder is evaporated.
The arrangement of the treatment elements 5 on the basic body 4 can be selected here in accordance with requirements.
The circular diameter of the basic body 4 is between 35 and 150 cm.
As shown in
The production of said basic body 4 is substantially facilitated by the application layer by layer.
If complete abrasion of the treatment elements 5 occurs as a result of wear during the refining treatment, this leads because of the overlap with the groove base to the opening of the channels 8 lying closest to the refining gap 3. This in turn has the result that the opened channels 8 now act as a groove 6, and the wall 9 between the opened channels 8 acts as a treatment element 5.
If the wall 9 between said first opened channels 8 is also abraded, the mutual partial overlapping means that further channels 8 are opened, the wall 8 of which takes on the function of the treatment elements 5.
In order to be able to ensure an identical treatment of the fibrous material 1 even as the wear increases, the channels 8 should each run at least approximately parallel to an elongate treatment element 5 lying axially approximately thereabove. A slight inclination of the channels 8 toward the refining gap 3, in particular radially outward, can be advantageous for the flow through them.
For reliable, homogeneous and efficient refining, the grooves 6 have at least predominantly a constant width. The width of the treatment elements 5 also remains at least predominantly the same size in the radial direction.
In order also to ensure this when the channels 8 or the wall 9 thereof take over the function of said grooves, the width of the channels 8 substantially corresponds to the width of the groove 6, and 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.
In order to ensure as high a number and as consistent a number of opened channels 8 as possible during the wear of the basic body 4, in the basic body 4 there are a plurality of planes 7 which lie one above another and are parallel to the refining gap 3, and each have a plurality of channels 8. The planes 7 illustrated in
The channels 8 of adjacent planes 7 are arranged here offset from one another in the direction of rotation 11. Furthermore, the channels 8 of adjacent planes 7 partially overlap in the direction of the rotation 11 such that, when a wall 9 is completely abraded, the adjacent channel 8 lying axially therebelow is opened.
By way of example, the height of the treatment elements 5 here is below 3 mm and the width of the treatment elements 5 is between 0.1 and 1 mm.
In order, during each state of wear, to be able to ensure an open groove surface which is as equally high as possible and a cutting edge length of the treatment elements 5 that is the same size as far as possible, it can be helpful, as can be seen in
Thus, as shown there, at least some of the planes 7 of two adjacent plate segments 2 are at differing distances from the refining gap 3.
Additionally or alternatively, however, the cross sections of the channels 8 of adjacent plate segments 2 can also differ. While the channels 8 of the one plate segment 2 are circular, the channels 8 of the adjacent plate segment 2 have here by way of example an elliptical cross section.
In addition, it is, of course, also possible for the plate segments 2 themselves to have differently configured zones, wherein the channels 8 of said zones are arranged differently and/or are configured differently.
Furthermore,
In contrast thereto,
It is essential here that the adjacent grooves 6 differ in depth in the starting state and during the wear.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 104 105.8 | Feb 2019 | DE | national |
This is a continuation of PCT application No. PCT/EP2019/085613, entitled “REFINER PLATE SEGMENT”, filed Dec. 17, 2019, which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2019/085613 | Dec 2019 | US |
| Child | 17406428 | US |
