[go: up one dir, main page]

WO1990003543A1 - Procede pour secher du bois - Google Patents

Procede pour secher du bois Download PDF

Info

Publication number
WO1990003543A1
WO1990003543A1 PCT/FI1989/000186 FI8900186W WO9003543A1 WO 1990003543 A1 WO1990003543 A1 WO 1990003543A1 FI 8900186 W FI8900186 W FI 8900186W WO 9003543 A1 WO9003543 A1 WO 9003543A1
Authority
WO
WIPO (PCT)
Prior art keywords
drying
wood
tunnel
substreams
section
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.)
Ceased
Application number
PCT/FI1989/000186
Other languages
English (en)
Inventor
Jarl-Gunnar Salin
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.)
Ekono Oy
Original Assignee
Ekono Oy
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 Ekono Oy filed Critical Ekono Oy
Priority to SU4830243/06A priority Critical patent/RU2080532C1/ru
Priority to DE68924974T priority patent/DE68924974T2/de
Priority to EP89910628A priority patent/EP0388459B1/fr
Publication of WO1990003543A1 publication Critical patent/WO1990003543A1/fr
Priority to NO902284A priority patent/NO176895C/no
Anticipated expiration legal-status Critical
Priority to LVP-93-645A priority patent/LV11064B/en
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/02—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure

Definitions

  • the present invention relates to a process for drying wood in a drying tunnel through which the wood is gradually fed and there permeated by drying air which flows in the longi ⁇ tudinal direction of the tunnel.
  • the present invention relates to such a process in which the drying tun ⁇ nel is divided into two sections separated by an intervening space and with the drying medium divided into two circulating substreams.
  • Sawn wood should be dried to a moisture content of approx. 15-22 %, calculated on the dry weight of the wood, in order that the wood can be stored without biological attack in the form of mould etc.
  • two main types of drying kiln are employed, so-called compartment kilns and progressive kilns (tunnel kilns) , whereas timber- yard drying has practically ceased.
  • drying schedule is meant how the temperature and moisture content of the drying air and its speed of flow through the wood pile are caused to vary during the drying period. It is therefore possible in this type of kiln to employ what is, by some criterium, the optimum drying schedule. This is the principal advantage of this kiln.
  • the disadvantages include a relatively high energy consumption and that these kilns cannot, be made especially large because otherwise the drying climate would vary too much in different parts of the wood load.
  • the pro ⁇ gressive kiln has the advantage that the energy consumption is appreciably lower since the air which leaves the kiln is almost saturated and also heat recovery can readily be ob ⁇ tained. Further, the progressive kiln can advantageously be constructed for high capacities, 10,000 - 20,000 m /annum.
  • a division of the progressive kiln into two stages has been proposed and has also come into use at some sawmills.
  • the drying air is introduced into the tunnel oetween the stages so that part flows in a counter- current direction in the first stage of the kiln and part in a concurrent direction in the second drying stage.
  • this two-stage pro ⁇ gressive kiln has advantages primarily in regard to control technology as it has a number of self-regulating properties.
  • the final moisture content of the wood after the desired drying time should be that which is aimed for, and on the other hand the quality loss of the wood in drying should be as little as possible or at least acceptable.
  • the speed of drying increases as the difference be ⁇ tween the dry-bulb and wet-bulb temperatures of the air in ⁇ creases.
  • the magnitude of the change in the quality of the wood is a more complicated function of the drying procedure, but roughly it can be said that the faster drying is carried out the greater are the quality losses.
  • the quality loss of the wood in drying can be divided into two main components.
  • One is that with high temperature levels and/or long drying times there is a flow of resin at knots etc. together with a darkening of the surface of the wood, the other is the occurrence of cracks in the wood.
  • crack formation is, especially with thicker dimen ⁇ sions, clearly the more important...
  • the cause of crack forma ⁇ tion can be explained in the following manner. In drying the surface of the timber dries faster than the inner parts of the piece of timber because of the resistance to the movement of moisture within the material. When the fibre saturation point is reached, i.e. when the free water has been removed and only water bound to the wood substance remains, the wood starts to shrink.
  • the present invention is accordingly based on the discovery that if the direction of flow of the drying air during the first stage of drying is countercurrent and during the lat ⁇ ter stage is concurrent in relation to the wood, then a low psychrometric difference is obtained during the period which is critical for the quality of the wood with a increasing psychrometic difference on either side of this point.
  • Figure 3 is pre ⁇ sented.
  • the psychrometric difference here decreases with time, which leads to a rapid drying at in the beginning, so that the fibre saturation point is reached al ⁇ ready after 12 hours, whereas the stress level does not now rise as high as in Figure 2.
  • the heating unit for the drying air fans for transport of the air through the timber, and the ventilation unit for maintenance of the desired air humidity.
  • Figure 4 shows an example comparable with Figures 2 and 3 and in which the same air (psychrometric difference 9.5°C) is fed into both drying stages and in which the air speeds (3.12 and 2.24 m/s respectively) are matched so that the pressure drops are the same, i.e. a situation which can be obtained using only a single common heating unit and a single fan unit. It is apparent from the figure that the stress peaks are practi ⁇ cally identical with the peaks in Figure 3. Further it is found that the drying air from each of the stages has almost the same condition (psychrometric difference approx. 4°C) .

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Abstract

L'invention se rapporte à un procédé pour sécher du bois, dans lequel le bois est acheminé progressivement à travers un tunnel de séchage tout en étant en même temps imprégné d'un milieu de séchage gazeux tel que de l'air transporté principalement dans le sens longitudinal du tunnel. Ledit tunnel de séchage est divisé en deux sections séparées, ledit milieu de séchage étant divisé en deux sous-courants de circulation dont un s'écoule à travers la première section du tunnel dans le sens de déplacement du bois et l'autre à travers la deuxième section du tunnel dans le sens contraire au déplacement du bois, après quoi lesdits sous-courants sont conditionnés et renvoyés à leurs sections.
PCT/FI1989/000186 1988-09-27 1989-09-27 Procede pour secher du bois Ceased WO1990003543A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
SU4830243/06A RU2080532C1 (ru) 1988-09-27 1989-09-27 Способ сушки древесины в туннельной сушилке
DE68924974T DE68924974T2 (de) 1988-09-27 1989-09-27 Verfahren zum trocknen von holz.
EP89910628A EP0388459B1 (fr) 1988-09-27 1989-09-27 Procede pour secher du bois
NO902284A NO176895C (no) 1988-09-27 1990-05-23 Fremgangsmåte ved törking av tre
LVP-93-645A LV11064B (en) 1988-09-27 1993-06-22 Process of drying wood in a drying tunnel

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI884428 1988-09-27
FI884428A FI98092B (fi) 1988-09-27 1988-09-27 Menetelmä puutavaran kuivaamiseksi

Publications (1)

Publication Number Publication Date
WO1990003543A1 true WO1990003543A1 (fr) 1990-04-05

Family

ID=8527099

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1989/000186 Ceased WO1990003543A1 (fr) 1988-09-27 1989-09-27 Procede pour secher du bois

Country Status (8)

Country Link
EP (1) EP0388459B1 (fr)
AT (1) ATE130929T1 (fr)
AU (1) AU4228389A (fr)
DE (1) DE68924974T2 (fr)
FI (1) FI98092B (fr)
LV (1) LV11064B (fr)
RU (1) RU2080532C1 (fr)
WO (1) WO1990003543A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008061264A3 (fr) * 2006-11-21 2008-09-18 Kurt Muehlboeck Procédé de séchage de bois assemblé sous forme de piles
AT510007B1 (de) * 2010-12-07 2012-01-15 Muehlboeck Kurt Verfahren zur holztrocknung
WO2013000421A1 (fr) 2011-06-30 2013-01-03 无锡碧杰生物材料科技有限公司 Amidon thermoplastique, matériau composite polyester biodégradable/amidon et son procédé de préparation

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2163328C1 (ru) * 1999-10-14 2001-02-20 Сныцерев Валерий Васильевич Способ конвективной сушки древесины
CN102889757A (zh) * 2012-10-24 2013-01-23 无锡市通和工机有限公司 洞道式干燥器
AT515466B1 (de) * 2014-02-26 2016-05-15 Mühlböck Kurt Verfahren zur Trocknung von Schüttgut
FI129413B (en) 2018-06-13 2022-01-31 Raute Oyj Method for incubating logs
CN109405445A (zh) * 2018-11-06 2019-03-01 中山市大涌镇志吉烘干厂 一种木材烘干工艺

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1729259A1 (de) * 1966-08-22 1972-05-18 Svenska Flaektfabriken Ab Verfahren und Vorrichtung zum Trocknen von Holz in einem Trockenkanal
AT335918B (de) * 1974-07-11 1977-04-12 Vanicek Viktor Trocknungsanlage, insbesondere trocknungskanal

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1729259A1 (de) * 1966-08-22 1972-05-18 Svenska Flaektfabriken Ab Verfahren und Vorrichtung zum Trocknen von Holz in einem Trockenkanal
AT335918B (de) * 1974-07-11 1977-04-12 Vanicek Viktor Trocknungsanlage, insbesondere trocknungskanal

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008061264A3 (fr) * 2006-11-21 2008-09-18 Kurt Muehlboeck Procédé de séchage de bois assemblé sous forme de piles
AT510007B1 (de) * 2010-12-07 2012-01-15 Muehlboeck Kurt Verfahren zur holztrocknung
WO2013000421A1 (fr) 2011-06-30 2013-01-03 无锡碧杰生物材料科技有限公司 Amidon thermoplastique, matériau composite polyester biodégradable/amidon et son procédé de préparation

Also Published As

Publication number Publication date
FI884428L (fi) 1990-03-28
RU2080532C1 (ru) 1997-05-27
EP0388459A1 (fr) 1990-09-26
AU4228389A (en) 1990-04-18
LV11064B (en) 1996-04-20
ATE130929T1 (de) 1995-12-15
LV11064A (lv) 1996-02-20
DE68924974D1 (de) 1996-01-11
EP0388459B1 (fr) 1995-11-29
FI98092B (fi) 1996-12-31
DE68924974T2 (de) 1996-05-02
FI884428A0 (fi) 1988-09-27

Similar Documents

Publication Publication Date Title
Elustondo et al. Advances in wood drying research and development
US4182048A (en) Method of drying lumber
US3199213A (en) Method of changing the moisture content of wood
US3939573A (en) Process for drying wood
US5197201A (en) Process for drying timber
US5687490A (en) Method of drying lumber
NO170369B (no) Fremgangsmaate ved innsamling av seismiske data til sjoes
Pang Moisture content gradient in a softwood board during drying: Simulation from a 2-D model and measurement
WO1990003543A1 (fr) Procede pour secher du bois
US3434222A (en) Method and an apparatus for the drying of wood in a channel
Pang et al. Drying rate and temperature profile for superheated steam vacuum drying and moist air drying of softwood lumber
US6910284B2 (en) Wood accelerating drying process based on its rheological properties
Pang et al. The application of mathematical models to the commercial high-temperature drying of softwood lumber
US2834120A (en) Lumber curing process
US3422545A (en) Timber drying process and apparatus
Price et al. Kiln time and temperature affect shrinkage, warp, and mechanical properties of southern pine lumber
US3070896A (en) Wood drying method
US3456356A (en) Method and an apparatus for drying wood
Rietz Accelerating the kiln drying of hardwoods
BE1029615A1 (nl) Werkwijze voor het drogen van een stapel hout
US3309778A (en) Wood drying method
FI102640B (sv) Förfarande vid torkning av virke
Mende et al. Simple camera for high-quality wood drying
NO176895B (no) Fremgangsmåte ved törking av tre
Chen et al. Stress relief for sapwood Pinus radiata boards by cooling and steam-conditioning processes

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU BB BG BR DK HU JP KP KR LK MC MG MW NO RO SD SU US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE BF BJ CF CG CH CM DE FR GA GB IT LU ML MR NL SE SN TD TG

WWE Wipo information: entry into national phase

Ref document number: 1989910628

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1989910628

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 1989910628

Country of ref document: EP