Classifications

• • 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
• • 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 present invention relates generally to disc refiners for lignocellulosic material. More particularly, the present invention relates to refiner plate segments for such an apparatus.
• the wood fibers are worked between two relatively rotating discs on which refiner plates are mounted.
• the plates usually have radial bars and grooves.
• a large volume of steam is produced between the plates as a result of this refining work.
• the fibrous material must be retained between the plates on the bar surfaces despite the high velocity of the flowing steam, and the enormous centrifugal forces.
• the steam is exhausted via the grooves, and dams are provided in the grooves to interrupt material flow and thus improve the retention time of the material in the refining region.
• the bars provide impacts or pressure pulses which separate and fibrillate the fibers.
• the grooves enable radially directed feeding of the fibers and steam extraction. Near the perimeter of the plates, high radial steam flow and high centrifugal force both act to sweep the fibers outwardly from between the plates prematurely, thus reducing the refining effectiveness.
• the flow restrictions due to a small gap between opposed plates and fiber-filled grooves result in a steam pressure peak between the plates, located radially inward from the perimeter. This pressure peak is a major source of the refining thrust load, and can induce control instability at high motor loads. It is thus desirable that the steam generated during refining be discharged from the refining region as quickly as possible, while retaining the pulp within the region as long as possible.
• the invention includes a refiner plate which is constituted from a plurality of refiner plate segments, each of the segments formed with a pattern including a refining zone having a plurality of radially disposed bar segments.
• Each of the bar segments has oppositely disposed radially inner and outer ends.
• a chicane extends obliquely from the outer end of an inner bar segment to the inner end of an outer bar segment to form a zig-zag shaped rib.
• Adjacent ribs define a plurality of zig-zag shaped grooves alternating with the ribs.
• the chicanes define at least one substantially arcuate line extending radially and laterally across at least the refining zone.
• This object is achieved by, in a preferred form, by providing chicanes that form a zig-zag flow path for most of the steam generated during the refining operation.
• a sloping leading face on each chicane directs the flow of the lignocellulosic material into the gap between the refiner plates for comminution on the grinding surfaces of the bars.
• the object of achieving good fiber quality with good steam management is accomplished by providing chicanes that direct the fiber into contact with the grinding surface while providing a plurality of flow paths for directing steam through the refining gap to the peripheral edge of the disc.
• chicanes that direct the fiber into contact with the grinding surface while providing a plurality of flow paths for directing steam through the refining gap to the peripheral edge of the disc.
• Figure 1 is an elevation view of a refiner plate segment in accordance with the invention
• Figure 2 is an enlarged section view along line 2-2 of Figure 1 ;
• Figure 3 is an enlarged elevation view of Area 3 of Figure 1 ;
• Figure 4 is an elevation view, partly broken away of a refiner plate including a plurality of the refiner plate segments in accordance with the invention
• Figure 5 is an elevation view of an alternate embodiment of the refiner plate segment of Figure 1 ;
• Figure 6 is an enlarged elevation view of Area 6 of Figure 5.
• a refiner plate in accordance with the present invention comprises a plurality of refiner plate segments 10 which are securable to the front face 1 2 of a substantially circular refiner disc 1 4 ( Figure 2).
• each segment 10 has two zones 1 6, 1 8 each having a differently oriented set of patterns, each segment 10 could alternatively have a single or three or more zones having respective sets of patterns ( Figure 1 ).
• the plate segments 10 are attached to the disc face 1 2, in any convenient or conventional manner, such as by bolts (not shown) passing through bores 20. One end of the bolt engages the disc 14 and at the other end has head structure bearing against a countersunk surface.
• the disc 1 only a portion of which is shown, has a center about which the disc rotates, and a substantially circular periphery.
• the refiner plate segments 1 0 are arranged side-by-side on the face 1 2 of the disc 14, to form a substantially annular refiner face, shown generally at 22 ( Figure 2).
• the face 22 forms a portion of a refiner region, when confronting another refiner plate (not shown) carried by another disc.
• each refiner plate segment 10 has an inner edge 24 near the center of the disc, an outer edge 26 near the periphery of the disc, and leading and trailing side edges 28, 30 which abut the trailing and leading side edges 30, 28 of adjacent refiner plate segments 10', respectively ( Figure 4).
• the remainder of this description will refer to a single plate segment 10, but it should be understood that all the segments which define the annular plate, are preferably substantially similar.
• the bars 32, 34 and grooves 36, 38 extend substantially radially, i.e., radially, or parallel to a radius of the disc, or obliquely at an acute angle to such a radius.
• the plate segment 1 0 has, on its face, at least one, and preferably two or three, distinct patterns of bars and grooves between the bars, whereby material to be refined can flow in the grooves in the general direction from the inner edge 24 to the outer edge 26 of the plate segment 10, 10' .
• a first or inlet zone 1 6 has a multiplicity of bars 34 and grooves
• each zone 1 6, 1 8 may comprise a plurality of fields, where each field has a uniform pattern. In the embodiment shown in Figure 1 , the segment has two fields in each zone.
• the patterns promote the flow of steam radially outward to the outer edge 26 of the disc 14 and radially inward to the inner edge 24 of the disc 14 for evacuation while retarding the flow of material to ensure that the material is fully refined. Since the disc 1 4 and plate rotate, the partially refined material is directed, as a result of centrifugal force, radially outward. Substantial quantities of steam are also generated in the refining zone 1 8 producing a steam flow with high radial velocity. Especially with relatively large discs, the centrifugal forces acting on the steam and partially refined chips increase dramatically as the material moves farther and farther radially outward. Although it is highly desirable that the steam be quickly exhausted from the refining region, it is essential that the partially refined fibers not be prematurely exhausted along with the steam.
• the refining zone 1 8 of the refiner plate segment 10 includes a plurality of radially extending first rib segments 40. With reference to Figure 3, each first rib segment 40 is connected at its radially outer end 42 to the radially inner end 44 of the next outer first rib segment 40' by a chicane 46.
• Each chicane 46 comprises a second rib segment that extends obliquely in the direction of disc rotation 48 from the inner first rib segment 40 to the outer first rib segment 40' to form a radially extending zig-zag bar 32.
• the inner side 50 of each chicane 46 slopes from the top 52 of the chicane 46 toward the adjacent chicane 46' to form a ramp face 54.
• the grooves 36 formed between adjoining ribs 32 define a zig-zag path substantially across the refining zone 1 8 for the movement of fibers.
• the lignocellulosic material traveling in the groove 36 is drawn into the corner of the chicane 46 and up the ramp face 54 of the chicane 46 by centrifugal force.
• the lignocellulosic material is therefore directed into the space or gap between the opposing refiner plates for additional comminution.
• the zig-zag path therefore retards movement of the lignocellulosic material, preventing material from exiting the refiner without having being sufficiently refined.
• the majority of the steam, which is less affected by the centrifugal force, continues traveling in the groove 36 to the periphery of the plate where it exits the refiner.
• the chicanes 46 define a series of substantially arcuate lines 56.
• the radially innermost end 58 of the lines 56 define an arc segment 60 positioned intermediate the outer edge 26 of the plate and the junction of the inlet and refining zones 1 6, 1 8.
• Each of the lines 56 extends from the arc segment 60 in the direction opposite to the direction of rotation 48 of the disc to the outer edge 26 of the plate such that the arc formed by the line of chicanes 46 has a substantially uniform radius from a point P.
• the chicanes 46 of the present invention cause an upwelling of feed material that constricts the plate gap in the vicinity of the chicanes 46.
• interrupted bars 84 may be disposed intermediate pairs of zig-zag bars 86, 88.
• the interrupted bars 84 are formed by providing a gap 90 between the radially outer end 92 of an inner rib segment 94 and the radially inner end 96 of an outer rib segment 98.
• the gaps 90 are disposed intermediate the chicanes 1 00 of the zig-zag bar pair 86, 88 and therefore extend obliquely in the direction of disc rotation 48.
• each line 56 of chicanes 46 that terminate on the trailing side edge 30 of a refiner plate segment 10 is positioned adjacent the radially inner end

Landscapes

• Paper (AREA)
• Crushing And Grinding (AREA)
• Confectionery (AREA)
• Medicines Containing Material From Animals Or Micro-Organisms (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=22267697

Family Applications (1)

Country Status (10)

Families Citing this family (7)

Family Cites Families (3)

• 1998
  • 1998-08-19 KR KR1020017001198A patent/KR20010106423A/ko active IP Right Grant
  • 1998-08-19 WO PCT/US1998/017162 patent/WO2000011264A1/fr active IP Right Grant
  • 1998-08-19 AT AT98940991T patent/ATE238447T1/de not_active IP Right Cessation
  • 1998-08-19 CA CA002337419A patent/CA2337419C/fr not_active Expired - Fee Related
  • 1998-08-19 DE DE69813910T patent/DE69813910T2/de not_active Expired - Fee Related
  • 1998-08-19 CN CN98814194A patent/CN1097126C/zh not_active Expired - Fee Related
  • 1998-08-19 EP EP98940991A patent/EP1105560B1/fr not_active Expired - Lifetime
  • 1998-08-19 BR BR9815989-5A patent/BR9815989A/pt not_active IP Right Cessation
  • 1998-08-19 AU AU89146/98A patent/AU742445B2/en not_active Ceased
• 2001
  • 2001-01-31 NO NO20010527A patent/NO313297B1/no not_active IP Right Cessation

Non-Patent Citations (1)

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