Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
  • D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
  • D21D5/18—Purification of the pulp suspension by mechanical means; Apparatus therefor with the aid of centrifugal force
  • D21D5/22—Purification of the pulp suspension by mechanical means; Apparatus therefor with the aid of centrifugal force in apparatus with a vertical axis

Definitions

• This invention relates to a device for separating heavy impurities from pulp suspensions and to a means for use in said device.
• separate devices can be installed before the screen, in order to eliminate the coarse impurities or to reduce their size, such as for example bull screen or refiner.
• Light impurities can also be separated in special devices before the screen. It is also possible to separate the coarse impurities in a first screening step in the screening device or to separate scrap and heavy particles when the suspension enters the screen, and other impurities at the fine screening. In the last mentioned case, the screening process can be disturbed by the impurities, as mentioned above.
• Fig. 1 shows a separation device according to the invention
• Fig. 2 shows a separation means according to the invention
• Figs. 3-6 show alternative embodiments of the separation means after the section II-II in Fig. 2.
• the separation device comprises an air-tight casing 1 with a stationary rotation symmetrical, preferably cylindric unperforated separation means 2 with vertical symmetry axis.
• a drum-shaped rotor 3 is provided, which extends along the entire separation means.
• the rotor 3 is concentric with the means 2, so that an overall treatment zone 4 is formed between the rotor 3 and separation means 2.
• the rotor 3 is supported on a rotary shaft 5.
• the rotor 3 is formed as a drum, which on the outside is provided with carrier means 6 extending into the treatment zone 4.
• An inject inlet 7 for the pulp is connected to the casing 1 for the supply of pulp at one end of the rotor 3.
• the inlet 7 can be arranged axially or tangentially.
• an outlet 8 for the treated pulp suspension is located at the opposite end of the casing 1 at the opposite end of the casing 1 at the opposite end of the casing 1 at the opposite end of the casing 1 at the opposite end of the casing 1 at the opposite end of the casing 1 .
• the separation means 2 is formed for separating heavy impurities downward to a reject chamber 9 with outlet 10 in connection to the lower edge of the separation means 2.
• the separation means 2 consists of a suitably rotation symmetrical, preferably cylindric shell plate, which on the inside is formed with grooves 11 , which extend axially or form an angle a. with the axial direction, which angle is between 0 and 45°, preferably 0-15°.
• the object is, that these grooves shall extend substantially perpendicular to the flow direction of the pulp through the treatment zone 4 by the effect of the carrier means 6 of the rotor 3.
• the grooves 11 can have different configuration, for example its cross-section can be rectangular, downward or upward tapering, saw-tooth shaped a.s.o.
• the grooves can also have different depth along the separation means with downward increasing depth.
• An overall ring 12 is located between the lower portion of the rotor 3 and separation means 2, in order to shield the reject chamber 9 from the treatment zone 4.
• Said ring 12 preferably is attached on the rotor 3, but alternatively can be attached on the separation means 2. This implies, that the grooves 11 communicate downwardly with the chamber 9.
• An inlet 13 for flushing liquid is connected to the chamber 9.
• the outlet 10 from the chamber 9 can be provided for continuous or discontinuous emptying, depending on the content of heavy impurities in the pulp.
• An inlet 14 for dilution liquid can possibly be connected to the upper end of the casing 1 for supplying dilution liquid to the upper end of the grooves 11.
• the function of the device is as follows.
• the pulp to be treated can have high concentration, preferably up to 6%. It is supplied to one end of the casing 1 through the inject inlet 7 and further to the treatment zone 4, through which it flows by the effect of the carriers 6 of the rotor 3. The pulp flow is thereby given a screw-shaped direction through the treatment zone 4. The treated pulp is thereafter taken out through the outlet 8 at the other end of the casing.
• the suspension enriched with heavey impurities, the reject will be moved down into the chamber 9, from where the reject is discharged through the outlet 10.
• flushing liquid can be supplied to the chamber 9 through the inlet 13.
• the concentration in the grooves can be reduced so that the material transport along the grooves is facilitated.
• the pulp is supplied at the upper end of casing 1.
• the pulp can be supplied from below with upward flow. The reject, however, is always taken out from the lower end of the casing.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Paper (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20406526

Family Applications (1)

Country Status (3)

Citations (4)

• 1997
  • 1997-04-10 SE SE9701337A patent/SE509133C2/sv not_active IP Right Cessation
• 1998
  • 1998-03-31 AU AU70891/98A patent/AU7089198A/en not_active Abandoned
  • 1998-03-31 WO PCT/SE1998/000590 patent/WO1998045532A1/en active Application Filing

Patent Citations (4)

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