WO1990006840A1 - Procede et appareil pour chauffer du bois ou d'autres matieres sensibles a la deshydratation et a la chaleur - Google Patents

Procede et appareil pour chauffer du bois ou d'autres matieres sensibles a la deshydratation et a la chaleur

Info

Publication number
WO1990006840A1
WO1990006840A1 PCT/DK1989/000294 DK8900294W WO9006840A1 WO 1990006840 A1 WO1990006840 A1 WO 1990006840A1 DK 8900294 W DK8900294 W DK 8900294W WO 9006840 A1 WO9006840 A1 WO 9006840A1
Authority
WO
WIPO (PCT)
Prior art keywords
wood
chamber
heating
temperature
steam
Prior art date
Application number
PCT/DK1989/000294
Other languages
English (en)
Inventor
Steen Ole Moldrup
Original Assignee
Steen Ole Moldrup
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 Steen Ole Moldrup filed Critical Steen Ole Moldrup
Publication of WO1990006840A1 publication Critical patent/WO1990006840A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
    • B27K3/02—Processes; Apparatus
    • B27K3/0278—Processes; Apparatus involving an additional treatment during or after impregnation
    • B27K3/0292—Processes; Apparatus involving an additional treatment during or after impregnation for improving fixation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K1/00—Damping wood
    • B27K1/02—Apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/001—Heating

Definitions

  • the invention relates to a method and apparatus for the heating of wood or other materials which are sensitive to dehydration and overheating.
  • these agents are characteristic in that the hexavalent chromium reacts with the organic components of the wood, and is hereby converted to trivalent chromium. During this process, the . main part of the chromium, copper, arsenic and phosphate forming part of the agents is precipitated as salts which are difficult to dissolve, and which only with difficulty can be washed out of the wood. This process is called fixation.
  • the speed at which the fixation takes place depends on a number of factors such as, for example, the precise chemical composition of the agents, the concentration of the impregnation agent, the kind of wood etc. However, the speed of fixation depends first and foremost on the temperature of the wood.
  • the heating is effected by the first method of heating with steam at a temperature of 100°C, and with the vacuum drying processes which are known from the similarly above-mentioned US patent publications no. 4,176,466, no. 4,194,296 - and no. 4,198,763, the heating is effected following the second of the two methods of heating, i.e. with hot air.
  • the heating is effected by the steam penetrating the wood pack, where it condenses on the surface of the wood and hereby heats the wood.
  • the penetration of steam into the wood takes place either by diffusion or as a consequence of the dynamic pressure which the vapours achieve in connection with the reduction in pressure which arises when the vapours are introduced into the heating chamber.
  • the greater the re ⁇ duction in pressure the greater will be the dynamic pressure.
  • the use of steam at high pressure in- volves the risk of overheating of the wood and of a strong drying out of the surface of the wood.
  • the heating is effected by hot air being circulated through the wood pack by natural or forced circulation.
  • a circulation of air through the wood pack presupposes that the wood has been carefully stacked with lists between the individual layers of wood.
  • the relative humidity of the air is kept constantly relatively high. This is done by introducing water to the air during the heating, and by ensuring that the temperature of the air does not signi ⁇ ficantly exceed the temperature of the wood. With a small temperature difference, the transfer of heat from the air to the surface of the wood will, however, take place very slowly, and the circulation of very large amounts of air is required.
  • the object of the present invention is therefore to pro ⁇ vide a method for the heating of wood and other materials which are sensitive to dehydration and overheating, by which method the necessary heating and drying of the rele- vant materials is effected in the quickest possible and
  • the transfer of heat will then take place very quickly, even with a small difference in temperature, and thus the heat transfer can take place with steam if the temperature is only slightly higher than the surface temperature of the material in the vacuum chamber, and as already mentioned it is a prerequisite to be able to ensure that the water vapours in the vacuum chamber can be held saturated.
  • Fig. 1 shows schematically an embodiment of the apparatus according to the invention
  • Fig. 2a and 2b show schematically two different embodi ⁇ ments of a steam generator in a condensate tank in the apparatus shown in fig. 1, and Fig. 3 shows the relationship between the surface temperature of material in the apparatus shown in fig.l and the pressure in this apparatus.
  • the heating takes place in an apparatus of the kind shown in fig. 1.
  • the apparatus consists of a vacuum chamber 1 with one or two covers 2 which can be opened.
  • the vacuum chamber must be completely airtight and must be able to withstand full vacuum.
  • the walls 3 of the vacuum chamber should be thermally insulated in order for better control to be effected over the climate in the chamber.
  • the vacuum chamber I is filled batchwise with the material 5 which is desired to be heated.
  • the material 5 is intro ⁇ quizd into the vacuum chamber 1 through the covers 2 in the chamber.
  • the covers 2 are closed and air is evacuated from the chamber 1 by means of a vacuum pump 6, an extractor or a similar element. With this evacuation, as much air as possible is removed from the vacuum chamber 1.
  • saturated water vapour 8 is introduced into the chamber at a temperature which is slightly higher than that of the material in the chamber.
  • the steam is easiest to produce by heating water placed in the vacuum chamber 1 itself or
  • a steam generator 7 which stands in direct connection with the vacuum chamber 1 (see fig. 2).
  • the vacuum chamber 1 In order to ensure that the water vapour produced is saturated and has the same temperature as the surface temperature of the mate ⁇ rial 5 in the vacuum chamber 1, it is important that there is no pressure regulating valve, cut-off or the like between the steam generator 7 and the vacuum chamber 1. The pressure and the temperature in the vacuum chamber and the steam generator must be the same.
  • a measuring element 14 which, in a commonly-known manner, is in connection with a not-shown control unit for the automatic control of the drying process.
  • Use can also be made of steam produced at high pressure in a separate steam generator.
  • the steam must be cooled and have moisture added before it comes into con ⁇ tact with the material 5 in the vacuum chamber 1.
  • This moisturizing is effected most expediently by leading the steam through a water bath, which is placed in the same manner as the water in the steam generator 7 described in the above.
  • the steam 8 will hereby be automatically saturated and assume approximately the same temperature as the surface temperature of the material 5 in the vacuum chamber 1.
  • the steam 8 produced in the steam generator 7 will condense on the surface of the material 5, whereby this is heated. Under gravitation, the condens- ed steam will seek towards the bottom of the vacuum chamber 1.
  • the condensate is collected from the bottom of the vacuum chamber by means of gravitation or by a condensate pump in a condensate tank 9. It can be advantageous to connect the condensate tank directly to the steam generator 7.
  • the pressure in the vacuum chamber 1 will depend on the surface temperature of the material 5 in the vacuum chamber in the relationship as shown in fig. 3, namely that the higher the temperature of the material 5, the greater will f also be the pressure in the vacuum chamber.
  • the steam pressure will be lowest in those areas of the vacuum chamber 1 which are the coldest.
  • the vapours 8 will there ⁇ by automatically seek towards the coldest parts of the va ⁇ cuum chamber 1, and possible temperature differences in the vacuum chamber 1 will thus be equalized rapidly and effectively. Since the movement of the water vapours 8 is due to pressure differences in the vacuum chamber 1, the vapours can penetrate deeply even into materials 5 which are packed tightly, and hereby the system distinguishes itself fundamentally from the earlier described systems of heating.
  • the problems of corrosion can be held on a relatively low level, for the reason that the system is devoid of air.
  • neutralizing amines such as, for example, morpholine
  • the neutralizing amines will remove the acids which emanate from the material 5 during the heating, and without oxygen and acids in the system the corrosion will be extremely limited.
  • the addition of amines is regulated most expe ⁇ trans by measuring the pH of the water collected in the condensate tank 9, and the amine is added in a manner so that the condensate water does not become acid at any time.
  • the walls 3 of the vacuum chamber 1 are provided with heating elements 4 which prevent the condensation of water vapours 8 on the inside walls of the vacuum chamber 1 by holding the temperature of the walls 3 at a slightly higher temperature than the dewpoint temperature of the vapours present in the chamber.
  • the condensate collected in the condensate tank 9 is re ⁇ used with advantage for the production of new steam, in that the condensate collected in the condensate tank is particularly suitable for steam production.
  • the condensate As a con ⁇ sequence of the process taking place in an air-free atmosphere, the condensate is totally devoid of oxygen. In the cases where neutralizing amines are added to the steam, the condensate is also completely devoid of corrosive acids.
  • a considerable amount of the water present in the material 5 can be removed from the material 5 by concluding the heating phase with the vacuum.
  • This concluding vacuum is established most easily by condensing the water vapours in the vacuum chamber 1 by means of not-shown cooling ele- ments disposed in the vacuum chamber 1 or in an also not- shown separate cooling tank. This condensation is effected relatively easily in the present system, as the system is completely evacuated of air prior to the concluding vacuum phase.
  • the condenser With air in the system, as with the known methods of heat ⁇ ing as discussed by way of introduction, the condenser must have a far greater cooling area and lower cooling temperature than required in the condensation of water vapours in an air-free atmosphere. As a consequence here ⁇ of, the system's economy is considerably diminished.
  • the method according to the invention thus affords a number of advantages in relation to the traditional methods of heating.
  • the method according to the invention is not, however, restricted to these applications, and can be used in almost all cases where there is a need for a quick and careful heating of wood or other materials which are sensitive to dehydration and overheating.
  • the method according to the invention can also be used with liquids other than water.
  • the vacuum chamber 1 it lies within the scope of the invention for the vacuum chamber 1 to be filled with hot water instead of with saturated water vapours.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

Procédé pour chauffer rapidement et doucement du bois ou d'autres matières sensibles à la déshydratation et aux lésions dues à la chaleur. On place la matière dans une chambre dont on a entièrement évacué l'air avant la phase de chauffage. On remplit alors la chambre avec de la vapeur d'eau saturée à une température qui ne dépasse pas de façon significative la température de la matière à chauffer. En pénétrant dans les espaces séparant les différentes parties de la matière et en se condensant sur la surface de la matière, la vapeur d'eau saturée chauffe cette matière. Ce procédé peut notamment être utilisé de manière avantageuse pour fixer un certain nombres de substances d'imprégnation dans du bois et pour sécher du bois. Un appareil pour la mise en ÷uvre de la présente invention est également décrit.
PCT/DK1989/000294 1988-12-16 1989-12-14 Procede et appareil pour chauffer du bois ou d'autres matieres sensibles a la deshydratation et a la chaleur WO1990006840A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK701988A DK701988D0 (da) 1988-12-16 1988-12-16 Fremgangsmaade til impraegnering af trae
DK7019/88 1988-12-16

Publications (1)

Publication Number Publication Date
WO1990006840A1 true WO1990006840A1 (fr) 1990-06-28

Family

ID=8149194

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK1989/000294 WO1990006840A1 (fr) 1988-12-16 1989-12-14 Procede et appareil pour chauffer du bois ou d'autres matieres sensibles a la deshydratation et a la chaleur

Country Status (4)

Country Link
AU (1) AU4809490A (fr)
CA (1) CA2005419A1 (fr)
DK (1) DK701988D0 (fr)
WO (1) WO1990006840A1 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994027102A1 (fr) * 1993-05-12 1994-11-24 Valtion Teknillinen Tutkimuskeskus Procede permettant d'ameliorer la resistance a la biodegradation et la stabilite dimensionnelle de produits cellulosiques
AU665058B2 (en) * 1992-03-12 1995-12-14 New Zealand Forest Research Institute Limited A bark extractant and method for preparing same
WO1995035191A1 (fr) * 1994-06-17 1995-12-28 Seidner Marc A Etuvage de bois et de produits ligneux
WO2003106123A2 (fr) * 2002-06-07 2003-12-24 Iwotech A/S Procede et dispositif pour le traitement thermique d'objets en bois
WO2007039590A1 (fr) * 2005-10-04 2007-04-12 Basf Se Procede pour produire des matieres a base de lignocellulose modifiees
US7939177B2 (en) 2005-10-04 2011-05-10 Basf Aktiengesellschaft Lignocelluosic material which is low in formaldehyde and method for the production thereof
US7963048B2 (en) * 2005-05-23 2011-06-21 Pollard Levi A Dual path kiln
US8201501B2 (en) 2009-09-04 2012-06-19 Tinsley Douglas M Dual path kiln improvement
FR3063925A1 (fr) * 2017-03-20 2018-09-21 Thermodynamic Workshop Training - Twt Dispositif de traitement thermique de grumes
US10619921B2 (en) 2018-01-29 2020-04-14 Norev Dpk, Llc Dual path kiln and method of operating a dual path kiln to continuously dry lumber

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1678559A (en) * 1927-05-28 1928-07-24 Joseph P Devine Drying materials
US2293453A (en) * 1939-02-24 1942-08-18 Gen Electric Dehydrating treatment
EP0199092A1 (fr) * 1985-03-22 1986-10-29 Dr. Wolman GmbH Procédé de fixage accéléré de sels de préservation de bois contenant du chromate
DE3630743A1 (de) * 1986-09-10 1988-03-24 Scholz Gmbh Co Kg Maschbau Verfahren und vorrichtung zur salzimpraegnierung von holz

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1678559A (en) * 1927-05-28 1928-07-24 Joseph P Devine Drying materials
US2293453A (en) * 1939-02-24 1942-08-18 Gen Electric Dehydrating treatment
EP0199092A1 (fr) * 1985-03-22 1986-10-29 Dr. Wolman GmbH Procédé de fixage accéléré de sels de préservation de bois contenant du chromate
DE3630743A1 (de) * 1986-09-10 1988-03-24 Scholz Gmbh Co Kg Maschbau Verfahren und vorrichtung zur salzimpraegnierung von holz

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU665058B2 (en) * 1992-03-12 1995-12-14 New Zealand Forest Research Institute Limited A bark extractant and method for preparing same
US5678324A (en) * 1993-05-12 1997-10-21 Valtion Teknillinen Tutkimuskeskus Method for improving biodegradation resistance and dimensional stability of cellulosic products
WO1994027102A1 (fr) * 1993-05-12 1994-11-24 Valtion Teknillinen Tutkimuskeskus Procede permettant d'ameliorer la resistance a la biodegradation et la stabilite dimensionnelle de produits cellulosiques
WO1995035191A1 (fr) * 1994-06-17 1995-12-28 Seidner Marc A Etuvage de bois et de produits ligneux
WO2003106123A3 (fr) * 2002-06-07 2009-03-26 Iwotech As Procede et dispositif pour le traitement thermique d'objets en bois
WO2003106123A2 (fr) * 2002-06-07 2003-12-24 Iwotech A/S Procede et dispositif pour le traitement thermique d'objets en bois
US7963048B2 (en) * 2005-05-23 2011-06-21 Pollard Levi A Dual path kiln
US7939177B2 (en) 2005-10-04 2011-05-10 Basf Aktiengesellschaft Lignocelluosic material which is low in formaldehyde and method for the production thereof
WO2007039590A1 (fr) * 2005-10-04 2007-04-12 Basf Se Procede pour produire des matieres a base de lignocellulose modifiees
AU2006298714B2 (en) * 2005-10-04 2011-08-11 Basf Se Production of modified lignocellulosic materials
US8201501B2 (en) 2009-09-04 2012-06-19 Tinsley Douglas M Dual path kiln improvement
US8342102B2 (en) 2009-09-04 2013-01-01 Douglas M Tinsley Dual path kiln improvement
FR3063925A1 (fr) * 2017-03-20 2018-09-21 Thermodynamic Workshop Training - Twt Dispositif de traitement thermique de grumes
WO2018172343A1 (fr) * 2017-03-20 2018-09-27 Thermodynamic Workshop Training - Twt Dispositif de traitement thermique de grumes
EA039559B1 (ru) * 2017-03-20 2022-02-10 Термодинамик Воркшоп Трейнинг - Твт Устройство для термической обработки бревен
US10619921B2 (en) 2018-01-29 2020-04-14 Norev Dpk, Llc Dual path kiln and method of operating a dual path kiln to continuously dry lumber

Also Published As

Publication number Publication date
CA2005419A1 (fr) 1990-06-16
DK701988D0 (da) 1988-12-16
AU4809490A (en) 1990-07-10

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