Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/02—Pretreatment of the raw materials by chemical or physical means
  • D21B1/021—Pretreatment of the raw materials by chemical or physical means by chemical means
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
  • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
  • D21B1/14—Disintegrating in mills
  • D21B1/18—Disintegrating in mills in magazine-type machines
  • D21B1/24—Disintegrating in mills in magazine-type machines of the pocket type

Definitions

• This invention relates to a method and an apparatus for the manufacture of mechanical or chemi-mechanical pulp from different lignocellulose materials, for example wood, bamboo or straw, for paper, paperboard etc. according to the preamble in claim 1.
• Mechanical pulps are manufactured of lignocellulose material, for example wood, in two ways different in principle, by grinding logs or by refining chips. At grinding the logs, i.e. the crosscut logs, are pressed against a rotating grindstone while water is being supplied thereto. At refining the chips are disintegrated to pulp between two refining discs rotating relative to each other.
• the method can be completed by heating the chips with steam at overpressure prior to and during the refining, the so-called thermomechanical process, and/or impregnating and possibly digesting the chips with a chemical solution prior to the refining, the so-called chemimechanical process.
• the patent application SE 8703744-6 teaches a method for impregnation with chemicals at the method according to the firstmentioned application.
• the methods according to said two patent applications as well as to conventional grinding are characterized in that the material has the form of pieces elongated in the fibre direction with a definite length, which pieces are defibered by pressing them, while water is supplied thereto, against a rotating defibering surface with the fibres oriented in a definite direction, viz. in the plane of the defibering surface and perpendicular to its running direction.
• this fibre orientation previously was obtained by laying the log manually into the feeding compartment of the grinder.
• conveying means are used which lay in the logs either continuously at grinding apparatuses operating continuously or in batches at grinding apparatuses operating batchwise.
• the wood is desired to be of a thickness as uniform as possible and to be as straight-grown as possible.
• the present invention has the object of solving the aforesaid problems and to render possible trouble-free feed of unit batches of impregnated and possibly digested material pieces, to the defibering apparatus with the fibres oriented in the plane of the defibering surface and perpendicular to its running direction and there to obtain controlled and effective defibering at low energy consumption.
• Fig. 1 shows a process layout for the entire pulp manufacturing
• Fig. 2 shows the treatment of the chemical-treated rods all there way to defibering
• Fig. 3 is a detal view of the compression to unit batches, blocks.
• Fig. 1 is shown how the incoming material, in this case roundwood crosscut to substantially equal lengths of at least 100 mm, suitably at least 200 mm and preferably at least 500 mm, is cleft at 1 to rods with a thickness of at maximum 50 mm, prererably at maximum 25 mm.
• the rods are impregnated with a chemical solution at 2 and digested at 3 in a digester.
• the rods are sluice into and out of the digester by means of rotary vane feeders 4 and 5, and the orientation of the fibre direction is maintained all the time by means of a conveyer 6 with dog within the digester.
• the rods are discharged from the digester by the rotary vane feeder 5 and drop down into a magazine 7 with the fibre direction substantially in the longitudinal direction of the magazine.
• the magazine has the form of a box with rectangular sides and is provided with a bottom and two vertical long sides having the same length as the rods.
• the box is open upwardly and to the two end walls. The box is charged with the amount of rods required for one block.
• the box When the box is filled, it is moved to a press 8, and a new box takes the place beneath the outlet of the rotary vane feeder 5.
• the rods in the filled box are pushed through one open end wall into the press 8 by means of a pressure plate 9 , which is operated by a compressed air cylinder 10.
• the empty box thereafter returns to the outlet of the rotary vane feeder 5.
• the press is provided with an upper and a lower horizontal perforated pressing plate 11.
• the rods which after the chemical treatment are soft, plastic and sticky, are compressed to a compact block.
• the excess cooking liquor simultaneously runs off through the perforations.
• the block can be compacted additionally by compressing it laterally by means of two pressing plates positioned vertically along the long sides of the block.
• the completed block shall have such dimensions as to fit in and fill completely the cross-section for the feed compartment of the defibering apparatus.
• the pressure at the pressing shall be sufficiently high to fill the spaces between the rods, but not so high as to degrade the structure of the wood.
• the pressure therefore, shall be at least 0.5 MPa and preferably be in the range 0.5-10 MPa .
• the block then is pushed by a pressure plate, preferably the same pressure plate 9 having fed the rods into the press, out of the press and into a second box 12, which is designed in the same way as the box 7, but has smaller dimensions so that it encloses the block tightly and holds it together.
• the box then is moved to a feed compartment 13 for a defibering apparatus 14, which is a grinder of conventional design.
• the feed compartment 13 consists of a vertical shaft with rectangular cross-section which with small clearance joins the curved surface of a grindstone 15.
• the internal cross-sectional dimension of the compartment agrees with the length and width of the block plus suitable clearances.
• One compartment wall perpendicular to the rotation axis of the stone is provided with an opening 16 for insertion of the blocks,which opening is closed by a cover 17.
• the compartment 13 holds two or more blocks stacked one upon the other.
• the blocks are pressed against the stone by a pressure plate 18, which fills completely the cross-section of the compartment and is loaded by a hydraulic cylinder 19. Water is simultaneously supplied to the stone through one or several spray pipes 20.
• the pressure plate 18 is moved up, the cover 17 is opened and a block is pushed via bhe open end wall of the box 12 through the opening 16 into the compartment by means of a compressed air operated pressure plate 21.
• the empty box 12 returns to the press 8.
• the cover 17 is closed, the pressure plate 18 again is moved down, and the grinding continues. The pulp ground-off is collected for further processing.
• Pressure plates and boxes can be replaced by other suitable devices.
• Grinders of other types with one or several vertical, inclined or horizontal compartments with batchwi ⁇ e or continuous feed can be applied.
• Two or more blocks can be pushed into the compartment one after the other in the fibre direction or in latitudinal direction.
• Defibering apparatuses of a type other than grinders, with pressing the block at simultaneous water addition against a rotating relief-patterned surface with the fibre direction substantially in the plane of the surface and perpendicular to its running direction, can be used.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20370568

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (7)

• 1987
  • 1987-12-11 SE SE8704948A patent/SE462223B/sv not_active IP Right Cessation
• 1988
  • 1988-10-18 AU AU27843/89A patent/AU2784389A/en not_active Abandoned
  • 1988-10-18 WO PCT/SE1988/000545 patent/WO1989005374A1/en unknown

Patent Citations (7)

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