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WO2025237944A1 - Surfaces de broyage pour le traitement d'une suspension aqueuse - Google Patents

Surfaces de broyage pour le traitement d'une suspension aqueuse

Info

Publication number
WO2025237944A1
WO2025237944A1 PCT/EP2025/062981 EP2025062981W WO2025237944A1 WO 2025237944 A1 WO2025237944 A1 WO 2025237944A1 EP 2025062981 W EP2025062981 W EP 2025062981W WO 2025237944 A1 WO2025237944 A1 WO 2025237944A1
Authority
WO
WIPO (PCT)
Prior art keywords
grinding
bars
division
dams
section
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/062981
Other languages
German (de)
English (en)
Inventor
Marcel Schmid
Martin Schmid
Marcus DR. BRITZ
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Voith Patent GmbH
Original Assignee
Voith Patent GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Voith Patent GmbH filed Critical Voith Patent GmbH
Publication of WO2025237944A1 publication Critical patent/WO2025237944A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C7/00—Crushing or disintegrating by disc mills
    • B02C7/11—Details
    • B02C7/12—Shape or construction of discs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C7/00—Crushing or disintegrating by disc mills
    • B02C7/02—Crushing or disintegrating by disc mills with coaxial discs
    • B02C7/06—Crushing or disintegrating by disc mills with coaxial discs with horizontal axis
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
    • D21D1/20—Methods of refining
    • D21D1/30—Disc mills
    • D21D1/306—Discs

Definitions

  • the invention relates to grinding plates with grinding surfaces for grinding an aqueous suspension, preferably for grinding suspended cellulose fibers, between two grinding surfaces forming a grinding gap and rotating relative to each other.
  • the grinding surfaces are formed by grinding ribs and grooves running between them.
  • the grinding surfaces are formed by replaceable grinding plates, also known as grinding assemblies, which are screwed to the corresponding support surface, due to the relatively rapid wear.
  • the grinding sets must be adapted as closely as possible to the fiber material being treated, also to prevent excessive wear of the sets.
  • EP 2 722 433 shows grinding plates or grinding plate segments with grooves and ribs.
  • the grooves of the grinding plate segments are either essentially completely blocked by full-height dams or partially blocked by full-height dams. In some designs, the dams are only located in the radially outer area between the grinding ribs.
  • Grinding plate segments with grinding guides are known from EP 1 670 592 B1.
  • the grinding guides are radially aligned. This allows these grinding plate segments to be used independently of the direction of rotation, and the direction of rotation can be changed during operation.
  • EP 4063561 and EP 3450624 show grinding plates with dams. The dams are arranged at an angle relative to the ridges to allow the return of any steam that forms to the radial center. Recesses are provided for the steam to pass through, so that the steam can take its path radially inward within the grinding surface and does not enter the gap formed between the grinding surfaces.
  • the invention is based on the objective of improving the efficiency of fiber treatment.
  • the fibers can be treated by the grinding elements with the reduced thickness. This increases the efficiency of such grinding elements.
  • the grinding bars are at least 10% thinner after division. It is particularly preferred that the grinding bars are at least 20% thinner, up to a maximum of 30% thinner, after division. A thickness of 25% thinner immediately after division is especially preferred. This ensures that the grinding bars are sufficiently stable for the stresses encountered, and the thinner grinding bars can then be used for additional processing of the fiber suspension.
  • the grinding elements are designed with openings for fastening in the grinding assembly.
  • the grinding elements are subject to wear and must be replaced regularly. Frequently, Openings in the grinding elements are provided for fastening.
  • higher loads can occur on the grinding bars adjacent to these openings.
  • the thickened or reinforced grinding bars are part of a division section prior to the division. This allows for optimal utilization of the grinding surface geometry of the grinding elements.
  • the reinforced sections of the grinding bars can then be further divided. This arrangement contributes to a dense arrangement of grinding bars, making such grinding elements particularly efficient.
  • dams are formed between circumferentially adjacent grinding bars. Suspension flowing in the grooves is conveyed by these dams into the grinding gap. Thus, the dams contribute to improved suspension treatment.
  • the dams are particularly preferably located in the radially outer region, so that improved mixing of the suspension from the grooves with the suspension flowing in the gap is achieved, promoting more homogeneous suspension treatment.
  • the grinding elements are designed for LC grinding:
  • LC milling refers to the treatment of suspensions in the range of 3% to 6% by weight.
  • the grinding elements with dams have proven particularly advantageous to integrate the grinding elements with dams into the stator of a grinding arrangement.
  • the dams allow backflow to be controlled and/or reduced. This has a particularly positive effect on power loss/idle power consumption.
  • the grinding bars are arranged radially outside the dividing section. This allows these grinding elements to be used independently of rotation. If the grinding elements are cast, the number of required molds is reduced, which has a beneficial effect on manufacturing costs. Furthermore, simplified inventory management is possible due to the reduced number of variants.
  • the grinding bars in the section after the division have a reduced thickness in the circumferential direction over at least 1/3, preferably 2/3, of the length of the section after the division.
  • the groove between the tapered grinding bars can first be brought to the groove width outside the division area, which has an advantageous effect on the flow behavior.
  • the width of the grooves in the circumferential direction is the same outside the division sections.
  • the grooves are machined with the minimum possible width. Making them narrower would increase the risk of clogging. Conversely, making the grooves wider than necessary would reduce the edge length and thus impair the processing capacity. The goal is to maximize the edge length while ensuring stable operation.
  • the grinding bars are of the same thickness outside the division sections.
  • dams are provided in the grooves, preferably in the radially outer region of 2/3 of the radial extent of the grinding element. This allows for improved fiber treatment.
  • the dams optimize the hydraulic capacity. It has been shown that with a reduced height of treatment elements, the flow direction in the stator changes from backflow to It is possible to reverse the forward flow. This forward flow is prevented by providing dams in the grooves.
  • a targeted increase in hydraulic capacity may be desired in the radially inner area in order to supply as much suspension as possible to the grinding arrangement.
  • the hydraulic capacity of the grinding surfaces typically decreases with increasing wear, and premature replacement of the grinding elements may be necessary due to insufficient hydraulic capacity.
  • By significantly increasing the grinding bar height in the radially inner area the open area in the inner region has been enlarged. This increases the hydraulic capacity and enables a longer service life.
  • the grinding bars and the dams are the treatment elements. A reduction in height occurs due to wear.
  • Adjacent grinding bars are particularly favored when connected by the dams. This contributes to the stability of the grinding surface.
  • an obtuse angle is provided radially inward between the dam and the grinding bar at the radially inner connection point. This allows the dams to function as grinding bars and also to treat the fibers of the fiber suspension. This further contributes to the efficiency of the grinding elements.
  • Grinding arrangement for grinding aqueous-suspended cellulose fibers between two grinding surfaces forming a grinding gap and rotating relative to each other. At least one of the grinding surfaces has at least one previously described grinding element.
  • At least one grinding surface is preferably provided with dams.
  • the dams are connected radially inside a grinding bar at an obtuse angle to form a treatment edge.
  • the suspension flows over the dam on the side.
  • the radially inward-positioned blunt angle of the dam is applied, and the material is treated by this boundary edge of the dam.
  • This inclined orientation of the dams increases the efficiency of the grinding arrangement, as the dams also act as treatment elements in addition to the grinding bars.
  • the grinding bars (21) are designed with an axial extent that is at least 15%, preferably 20%, greater radially inward than radially outward.
  • the variation in the axial extent of the grinding bars is not greater than 25% from the axial extent of the grinding bars in the radially outer region.
  • the increase in the height of the grinding bars is gradual.
  • the grinding bar height of the grinding bars starting radially inward is considered to be the height after reaching the maximum height, i.e., after the end of the radially inward chamfer.
  • the end of the grinding bars is considered to be radially outward up to -5% radially inward.
  • the flow direction of the suspension is determined by the relative movement of the grinding surfaces and, in the case of radial inward feeding, always has a flow component towards the radial outward.
  • Fig. 1 Schematic cross-section through a grinding arrangement
  • Fig. 2 Segment of a grinding plate with dams in the radially outer area
  • Fig. 3 Representation of a section of a segment of a grinding plate
  • Fig. 4 Detailed view of the branching area
  • FIG. 7 Superimposed representation of the grinding surfaces
  • Figure 1 shows a grinding arrangement 1.
  • a grinding gap 3 is formed by a stationary grinding surface coupled to the housing and a grinding surface 4 rotating about a rotational axis 10.
  • Such grinding arrangements for treating fiber-containing suspensions are also called refiners.
  • Refiners are used in particular in the fiber processing of cellulose fibers.
  • the two annular grinding surfaces 4 run parallel to each other, with the distance between them typically being adjustable. In addition to the flat grinding surfaces 4 shown here, conical grinding surfaces, also known as treatment surfaces, are possible.
  • the rotating grinding surface 4 is moved in the direction of rotation by a shaft 12, which is rotatably mounted in the housing. This shaft 10 is driven by a drive mechanism (not shown).
  • the fiber suspension 1 to be ground enters the grinding gap 3 between the two grinding surfaces 4 via an inlet through the center.
  • feeding via openings in the grinding surface is also possible.
  • the fiber suspension S passes radially outwards through the interacting grinding surfaces 4 and exits the subsequent annular space through an outlet 6.
  • Each grinding surface 4 is formed by several circular segment or annular segment-shaped grinding segments 8 as grinding elements according to Figure 2. However, the grinding surface 4 could also be formed by a single grinding element 2.
  • the grinding elements 2 have a base plate 18. Treatment elements 20, here grinding bars 21 and dams 23, are provided on the base plate. In the illustration according to Figure 2, the dams formed between the grinding bars 21 are located in the radially outer region.
  • the grinding segments 8 extend circumferentially and are arranged side by side circumferentially. Each grinding segment 8 is supported by a base plate 18 with a plurality of treatment elements 20 and intervening grooves 22. formed. Grinding bars 21 and dams 23 are provided as treatment elements 20.
  • the grinding bars 21 have an elongated cross-sectional shape, with the upper side of the grinding bars 21, which faces the treatment gap 3, generally running parallel to the outer surface of the base plate 18.
  • the dividing section 26 Radially inward from the division 27, the dividing section 26 has a thickened grinding bar in the region 28. After the division into two grinding bars 21, the grinding bars 21 are tapered over a partial region 29 of the section following the division 27. Outside the dividing section 26, the grinding bars 21 have identical thickness.
  • the grooves 22 have constant diameters outside the dividing sections.
  • dams 23 are provided in the grooves 22. The dams 23 are connected to the adjacent grinding bars 21. The dams 23 are arranged at an angle to the grinding bars 21 and have an obtuse angle 24 radially inward.
  • the orientation of the dams 23 depends on the flow direction of the suspension in the grinding gap 3.
  • the radially inward-facing boundary edge of the dams 23 is exposed to the flow of the suspension.
  • This boundary edge of the dams 23 thus acts as a treatment edge 25 and contributes to the treatment efficiency.
  • the grinding elements are preferably used in accordance with the direction of rotation.
  • the grinding surfaces with grinding elements with differently oriented dams 23 are to be used if the grinding surfaces of the rotor 16 are arranged axially between the grinding surfaces of the stator.
  • Figure 4 shows an enlarged view of a division section. The groove 22 after the division.
  • the section 27 of a grinding bar 21 is extended radially inwards by a region 31, in particular to increase the edge length of the grinding bars 21.
  • the thickness 30 of the grinding bar 21 is reduced at the same time; however, due to the connection of the grinding bars 21 before the division 27, the grinding bars 21 are mechanically reinforced in this region, and the reduced thickness of the grinding bars in region 29 does not result in any loss of load-bearing capacity.
  • Figure 5 shows a grinding segment with openings 35 for mounting in a grinding arrangement 1. Grinding bars with thickened areas 28 are arranged circumferentially adjacent to the openings 35. Here, the thickened areas
  • dams 23 has the disadvantage that the cutting edge length of the grinding bars 21 is reduced. To compensate for this loss and even to increase the cutting edge length of the grinding bars 21, these dams 23 are positioned such that the desired cutting angle is achieved between the dams 23 of the stator 17 and the grinding bars 21 of the rotor 16. The relative movement between the rotor 16 and the stator 17 causes the cutting angle between the grinding bars 21 of the rotor 16 and the dams 23 of the stator 17 to close in the direction of the inner diameter. The dams 23 thus also take over the function of the grinding bars of the stator.
  • the angle distribution of the grinding bars 21 from rotor 16 to stator 17 is modified.
  • the grinding bars are arranged radially aligned at 0° with a deviation of +/-5°.
  • the grinding bars 23 of rotor 16 are arranged with a predetermined radial inclination angle, for example, 30° to the radial. This improves the pumping action of the grinding surfaces of rotor 16 and stator 17.
  • the laterally extending grinding bars 21 are designed with a greater thickness. This reduces damage caused by foreign parts/contaminants in the suspension.
  • FIG 6 shows grinding bars 21.
  • the grinding bars 21 have an axially extended extent 31, also referred to as the grinding bar height.
  • the volume of the grooves 22 bounded between the grinding bars is thereby increased in this region.
  • the grinding element 2 has a constant axial extent.
  • the gap width remains unchanged.
  • the base plate 18 supporting the grinding bars has a reduced thickness 19 in the radially inner region. The reduced thickness of the base plate 18 compensates for the greater extent of the grinding bars 21 in the inner region. This results in improved suspension flow in the radially inner region.
  • the hydraulic capacity of the grinding segments typically decreases with increasing wear, and premature removal of the grinding elements 2 may be necessary. This may be necessary due to insufficient hydraulic capacity.
  • the open area in the inner region of the grinding element 2 can be significantly increased by a substantial increase in the height of the grinding bars 21 radially inwards, for example by 1 mm to a maximum of 3 mm, and in particular by 1.5 mm.
  • the heights of the grinding bars 21 in the radially outer region are typically initially 10 mm, 8 mm, or 6 mm. With a continuous increase of 1.5 mm radially inwards, a grinding bar height of 8 mm at the outer radius would thus initially result in a grinding bar height of 9.5 mm.
  • Figure 7 shows the path of the treatment elements 20 of the rotor and stator assembly.
  • the path of the grinding bars of the rotor 16 is shown in the foreground.
  • the path of the grinding bars 21 and the dams 23 of the stator 17 is shown.
  • the treatment elements facing each other in the gap and their interaction result from the relative position of the treatment elements to one another.
  • the treatment edge 25 is clearly visible.

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Paper (AREA)
  • Polishing Bodies And Polishing Tools (AREA)

Abstract

L'invention concerne un élément de broyage (2) pour un raffineur, comprenant des bandes de broyage (21) et des rainures (22) s'étendant entre les bandes de broyage (21), certaines des bandes de broyage (21) fendues radialement vers l'extérieur dans une région de division (26) et les bandes de broyage (21) ayant une épaisseur plus petite dans la direction circonférentielle dans au moins une partie après la division (27) dans la région de division (26) qu'à l'extérieur de la région de division (26).
PCT/EP2025/062981 2024-05-15 2025-05-13 Surfaces de broyage pour le traitement d'une suspension aqueuse Pending WO2025237944A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102024113542.5A DE102024113542A1 (de) 2024-05-15 2024-05-15 Mahlflächen zur Behandlung von wässriger Suspension
DE102024113542.5 2024-05-15

Publications (1)

Publication Number Publication Date
WO2025237944A1 true WO2025237944A1 (fr) 2025-11-20

Family

ID=95899611

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2025/062981 Pending WO2025237944A1 (fr) 2024-05-15 2025-05-13 Surfaces de broyage pour le traitement d'une suspension aqueuse

Country Status (3)

Country Link
CN (1) CN120967713A (fr)
DE (1) DE102024113542A1 (fr)
WO (1) WO2025237944A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2156321A (en) * 1936-04-01 1939-05-02 Lionel M Sutherland Fiber pulp refiner
US3473745A (en) * 1967-01-11 1969-10-21 Sprout Waldron & Co Inc Refining plate for high consistency pulp
EP1670592B1 (fr) 2003-10-06 2009-12-30 Metso Paper, Inc. Element de raffinage
DE102012214980A1 (de) * 2012-08-23 2014-02-27 Voith Patent Gmbh Kegelrefiner
EP2722433A1 (fr) 2012-10-18 2014-04-23 Andritz, Inc. Plaques de raffineur dotées de segments à courtes rainures de raffinage de matière lignocellulosique et procédés associés
WO2016128092A1 (fr) * 2015-02-10 2016-08-18 Voith Patent Gmbh Garniture de raffinage
EP3450624A1 (fr) 2017-09-01 2019-03-06 Valmet Ab Segment de raffinage dans un raffineur de fibres
EP4063561A1 (fr) 2021-03-24 2022-09-28 Valmet Ab Segment de raffineur

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI20075688A7 (fi) * 2007-09-28 2009-03-29 Valmet Technologies Inc Jauhin
CA3114202A1 (fr) * 2018-10-11 2020-04-16 Andritz Inc. Plaque de raffineur ayant des saillies d'usure entre les barres

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2156321A (en) * 1936-04-01 1939-05-02 Lionel M Sutherland Fiber pulp refiner
US3473745A (en) * 1967-01-11 1969-10-21 Sprout Waldron & Co Inc Refining plate for high consistency pulp
EP1670592B1 (fr) 2003-10-06 2009-12-30 Metso Paper, Inc. Element de raffinage
DE102012214980A1 (de) * 2012-08-23 2014-02-27 Voith Patent Gmbh Kegelrefiner
EP2722433A1 (fr) 2012-10-18 2014-04-23 Andritz, Inc. Plaques de raffineur dotées de segments à courtes rainures de raffinage de matière lignocellulosique et procédés associés
WO2016128092A1 (fr) * 2015-02-10 2016-08-18 Voith Patent Gmbh Garniture de raffinage
EP3450624A1 (fr) 2017-09-01 2019-03-06 Valmet Ab Segment de raffinage dans un raffineur de fibres
EP4063561A1 (fr) 2021-03-24 2022-09-28 Valmet Ab Segment de raffineur

Also Published As

Publication number Publication date
DE102024113542A1 (de) 2025-11-20
CN120967713A (zh) 2025-11-18

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