Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
  • B27N3/08—Moulding or pressing
  • B27N3/086—Presses with means for extracting or introducing gases or liquids in the mat
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
  • B27N3/08—Moulding or pressing
  • B27N3/24—Moulding or pressing characterised by using continuously acting presses having endless belts or chains moved within the compression zone
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N7/00—After-treatment, e.g. reducing swelling or shrinkage, surfacing; Protecting the edges of boards against access of humidity

Definitions

• the present invention relates to a method of producing continuously lig- nocellulose-containing boards in accordance with the preamble of claim 1 , and to an arrangement for carrying out the method in accordance with the preamble of claim 5.
• Methods of producing lignocellulose-containing board are well known to the art and have found wide use in practice.
• the manufacture of such boards in- eludes the following main method steps: disintegration of the raw material into particles and/or fibres of appropriate size, drying the particles and/or fibres to a determined moisture quotient and glue-coating the material either prior to or subsequent to said drying process, shaping the glue-coated material to form a mat, which may comprise several layers, and optionally cold pre-pressing the mat, pre- heating said mat, water-spraying mat surfaces, etc., and heat pressing the mat in a discontinuous press or in a continuous press while subjecting the material simultaneously to pressure and heat so as to obtain a finished board.
• Another known phenomena is that boards produced in this way obtain mutually different moisture contents in the surface layers relative to the core layer. If the boards are used for some type of sur ace treatment for instance, such as lamination, without having earlier equalised the difference in moisture content, the dimensions of the board may change when this equalisation takes place in time so that the surface layer loosens. In order to achieve desired equalisation between the various layers, it is customary to store the boards for a number of weeks. Another known problem is that the boards are not dimensionally stable when they leave the press. This is noticeable primarily because the boards shrink or swell over a process that can take one or more days. Consequently, calibration grinding of the boards is not normally undertaken until the boards have been stored in intermediate storage locations over a number of days.
• Another known problem is that the boards are too hot to be stacked and stored when leaving the hot press. If the boards are too hot when stacked, the glue joints may begin to break down and the boards consequently weakened. This problem is normally alleviated by keeping the boards in a so-called cooling wheel in which the board temperature is lowered by natural convection.
• the object of the present invention is to stabilise a board with respect to its moisture content, temperature and dimensional stability in a continuous process, and therewith avoid cost-inducing handling and storage of the board. Because dimensional stability is achieved, the boards may also be ground or sanded down to a final thickness directly after manufacture. This object is achieved with the method and the apparatus defined in the characterizing clauses of respective claims.
• each after-conditioning unit 5, 6 comprises an air supply unit 8 that includes a suction fan 9 and a heater 10.
• a steam or water supply device 11 may also be provided for moistening the air. The air is sucked into the two air supply units at 12. As will be seen from the drawing, the air is delivered from above in the case of the after-conditioning unit 5, and from be- neath in the case of the after-conditioning unit 6.
• the boards exit from the continuous steam injection press 2 they pass into the after-conditioning zone 4 in which air is sucked through the boards with the aid of negative pressure in an amount determined in relation to board production and at a specific moisture content and temperature.
• the air is sucked down through the board, whereas in the after- conditioning unit 6 the air is sucked through the board in the opposite direction, i.e. upwards.
• this double air flow in mutually opposite directions is not necessary in order to achieve an effect since in certain cases the throughflow of air in only one direction will suffice, meaning that only one after-conditioning unit will be required.
• a board having a density of 600 kg/m 3 and a thickness of 16.6 mm is cooled from 100 to 60°C in 60 seconds when applying a subpressure of 15 kPa.
• a board having a density of 600 kg/m 3 and a thickness of 32 mm is correspondingly cooled in 80 seconds.
• board having a thickness of 10 mm and a density of 650 kg/m 3 and produced in accordance with the invention in a pilot plant obtained a stable thickness after having passed through the after-conditioning zone. Measurements made one or more days after manufacture showed that boards which had passed through the after-conditioning zone retained their thickness, whereas boards that had not passed through said zone were often liable to shrink up to 1 mm within a day or two, in the same way as conventionally manufactured board shrinks.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Compounds Of Unknown Constitution (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20414320

Family Applications (1)

Country Status (14)

Cited By (3)

Families Citing this family (2)

Citations (2)

• 1999
  • 1999-02-01 SE SE9900332A patent/SE514351C2/sv not_active IP Right Cessation
• 2000
  • 2000-01-31 EP EP00906823A patent/EP1157165B1/en not_active Expired - Lifetime
  • 2000-01-31 NZ NZ513743A patent/NZ513743A/xx unknown
  • 2000-01-31 KR KR1020017009257A patent/KR20010092798A/ko not_active Application Discontinuation
  • 2000-01-31 CA CA002356062A patent/CA2356062A1/en not_active Abandoned
  • 2000-01-31 CZ CZ20012763A patent/CZ20012763A3/cs unknown
  • 2000-01-31 AU AU28380/00A patent/AU2838000A/en not_active Abandoned
  • 2000-01-31 PL PL00350051A patent/PL350051A1/xx unknown
  • 2000-01-31 CN CNB008030197A patent/CN1167849C/zh not_active Expired - Fee Related
  • 2000-01-31 AT AT00906823T patent/ATE264943T1/de not_active IP Right Cessation
  • 2000-01-31 WO PCT/SE2000/000187 patent/WO2000044985A1/en not_active Application Discontinuation
  • 2000-01-31 JP JP2000596217A patent/JP2002535185A/ja not_active Withdrawn
  • 2000-01-31 DE DE60010056T patent/DE60010056T2/de not_active Expired - Fee Related
• 2001
  • 2001-07-30 NO NO20013728A patent/NO20013728L/no not_active Application Discontinuation

Patent Citations (2)

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