EP0252915B1 - Method at the manufacture of mechanical pulp - Google Patents

Method at the manufacture of mechanical pulp Download PDF

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Publication number
EP0252915B1
EP0252915B1 EP19860902922 EP86902922A EP0252915B1 EP 0252915 B1 EP0252915 B1 EP 0252915B1 EP 19860902922 EP19860902922 EP 19860902922 EP 86902922 A EP86902922 A EP 86902922A EP 0252915 B1 EP0252915 B1 EP 0252915B1
Authority
EP
European Patent Office
Prior art keywords
disc
refiner
accelerometer
measured
pulp
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.)
Expired
Application number
EP19860902922
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0252915A1 (en
Inventor
Nils J. Ch. Hartler
William Carlstad Strand
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.)
Valmet AB
Original Assignee
Sunds Defibrator Industries AB
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 Sunds Defibrator Industries AB filed Critical Sunds Defibrator Industries AB
Priority to AT86902922T priority Critical patent/ATE60815T1/de
Publication of EP0252915A1 publication Critical patent/EP0252915A1/en
Application granted granted Critical
Publication of EP0252915B1 publication Critical patent/EP0252915B1/en
Expired legal-status Critical Current

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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
    • D21D1/002—Control devices
    • 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

Definitions

  • This invention relates to a method of controlling the manufacture of mechanical pulp in a refining process where cellulose-containing material in lumps, such as wood chips, is refined.
  • the chips prior to the refining can be treated with heat and/or chemicals for manufacturing TMP (thermomechanical pulp) or CTMP (chemi-thermomechanical pulp).
  • TMP thermomechanical pulp
  • CTMP chemi-thermomechanical pulp
  • the refining is carried out in one or several steps by single- or double-disc refiners. These refiners are provided with opposed refiner discs rotating relative one another.
  • the discs are provided with disc segments comprising bars and intermediate grooves. Opposed disc segments form a gap where material is refined during its passage outward.
  • the properties of the manufactured pulp are influenced, besides by the quality of the wood chips, by a great number of system parameters.
  • system parameters can be mentioned the distance between the disc segments (gap), the load of the motor driving a rotary refiner disc, the pressure by which the refiner discs are pressed in the direction toward each other, the pressure at the feed-in of the chips, the pressure in the housing enclosing the discs, the supply of diluting water, the material flow through the refiner (the production), the material concentration.
  • Some of these parameters are depending on each other while other are substantially independent. For example, the motor load increases and so does the pressure by which the discs are pressed toward each other when the gap decreases.
  • a great problem is that the measuring of the system parameters does not yield a direct measure of the pulp properties.
  • the properties of the pulp such as tensile strength, tearing resistance, dewatering capacity, shives content, fibre length etc.
  • the present invention offers a solution of this problem.
  • the invention implies that the vibrations arising in the refiner discs during the refining are utilized for calculating the pulp properties.
  • the characterizing features of the invention become apparent from the attached claims.
  • the frequency depending on the rotation speed of the discs and the design of the disc segments can amount to several thousands c.p.s.
  • the measuring is carried out by means of an accelerometer attached to the disc, preferably to the rear side of a segment. In a single-disc refiner the accelerometer is attached on the stationary disc. It is also imaginable to attach accelerometers to both discs in a single- or double-disc refiner, in order to obtain additional information on the vibrations of the discs.
  • vibration energy also can be utilized for determining the condition of the processing surfaces of the segments.
  • the vibration energy furthermore, can be utilized for comparing the efficiency of disc segments of different types.
  • an accelerometer was mounted in a hole drilled in the rear side of a disc segment in the stationary disc.
  • the segments were designed with three zones comprising bars and grooves of different size.
  • the signal from the accelerometer was simultaneously measured and analysed.
  • the frequency range in question was 5-25 kc/s.
  • Figure 1 a frequency analysis of this signal is shown.
  • the signal can be divided into three different areas corresponding to the three zones of the segments. In the inner zone comprising the coarsest bars the frequencies 5.& - 11.2 kc/s were noted. In the central zone 11.2-17.6 kc/s, and in the outer zone comprising the finest bars 17.6-25 kc/s were noted.
  • the vibration energy is represented by the surface beneath the frequency curve in Figure 1.
  • the deterioration in the tensile strength of the pulp can be explained by the wear of the disc segments.
  • the present invention offers such a control possibility.
  • the condition of the disc segments can be determined, which also can be utilized for determining the time when the segments have to be exchanged.
  • the invention can also be used for comparing different segment patterns and materials.

Landscapes

  • Paper (AREA)
EP19860902922 1985-05-06 1986-04-08 Method at the manufacture of mechanical pulp Expired EP0252915B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86902922T ATE60815T1 (de) 1985-05-06 1986-04-08 Herstellungsverfahren mechanischer pulpe.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8502211A SE454189B (sv) 1985-05-06 1985-05-06 Sett att kontrollera den framstellda massans egenskaper i en raffinorprocess genom utnyttjande av uppmetta vibrationer i maldonen
SE8502211 1985-05-06

Publications (2)

Publication Number Publication Date
EP0252915A1 EP0252915A1 (en) 1988-01-20
EP0252915B1 true EP0252915B1 (en) 1991-02-06

Family

ID=20360089

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860902922 Expired EP0252915B1 (en) 1985-05-06 1986-04-08 Method at the manufacture of mechanical pulp

Country Status (8)

Country Link
EP (1) EP0252915B1 (sv)
JP (1) JPS62502759A (sv)
AU (1) AU599914B2 (sv)
CA (1) CA1281571C (sv)
FI (1) FI874879A0 (sv)
NZ (1) NZ216017A (sv)
SE (1) SE454189B (sv)
WO (1) WO1986006770A1 (sv)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5605290A (en) * 1995-06-02 1997-02-25 The Lektrox Company Apparatus and method for particle size classification and measurement of the number and severity of particle impacts during comminution of wood chips, wood pulp and other materials
GB2331469A (en) * 1997-11-25 1999-05-26 Univ Bradford Pulp refiner
SE529525C2 (sv) * 2006-01-16 2007-09-04 Metso Paper Inc Förfarande och anordning för kontroll av uppriktningen mellan malytor
FI128873B (sv) * 2019-12-17 2021-02-15 Valmet Technologies Oy Arrangemang och förfarande för reglering av skärbettens bettmellanrum i en raffinör
FR3135994B1 (fr) 2022-05-30 2024-05-10 Kadant Lamort Procede d’optimisation de l’energie de raffinage pendant une operation de raffinage d’une composition de fibres
SE2251404A1 (en) * 2022-12-02 2024-06-03 Cellwood Machinery Ab Gap width monitoring

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3604646A (en) * 1969-12-10 1971-09-14 Beloit Corp Mass rate control system for paper stock refiners
US3604645A (en) * 1969-12-10 1971-09-14 Beloit Corp Inferential mass rate control system for paper refiners
FI57797C (fi) * 1977-07-05 1980-10-10 Yhtyneet Paperitehtaat Oy Visaranordning foer en raffinoers driftstoerningar
CA1105604A (en) * 1978-06-07 1981-07-21 James H. Rogers Method and system for detecting plate clashing in disc refiners

Also Published As

Publication number Publication date
SE454189B (sv) 1988-04-11
AU599914B2 (en) 1990-08-02
AU5863286A (en) 1986-12-04
SE8502211L (sv) 1986-11-07
SE8502211D0 (sv) 1985-05-06
EP0252915A1 (en) 1988-01-20
FI874879A (fi) 1987-11-04
NZ216017A (en) 1989-01-27
WO1986006770A1 (en) 1986-11-20
FI874879A0 (fi) 1987-11-04
JPS62502759A (ja) 1987-10-22
CA1281571C (en) 1991-03-19

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