Heating Panel, Treatment Apparatus, And Method For Treating Wood Material

Abstract

The invention is a heating panel (10) for treating wood material (22), comprising two boundary members (12) arranged parallel to each other, and a heating wire (14) arranged between the boundary members (12).

The heating panel (10) is characterised in that the heating panel (10) further comprises a solidified wood treatment composition (16) arranged between the boundary members (12) and surrounding the heating wire (14), and the boundary members (12) are configured to allow the solidified wood treatment composition (16) to contact the wood material (22) to be treated.

The invention is furthermore a treatment apparatus (20), and a method for treating wood material (22).

Claims

1. A heating panel (10) for treating wood material (22), comprising two boundary members (12) arranged parallel to each other, and a heating wire (14) arranged between the boundary members (12), characterised in that the heating panel (10) further comprises a solidified wood treatment composition (16) arranged between the boundary members (12) and surrounding the heating wire (14), and the boundary members (12) are configured to allow the solidified wood treatment composition (16) to contact the wood material (22) to be treated.

2. The heating panel (10) according to claim 1, characterised in that the boundary member (12) is a perforated plate or grating.

3. The heating panel (10) according to claim 1, characterised in that the boundary member (12) is made of a heat conducting material.

4. The heating panel (10) according to claim 1, characterised in that the solidified wood treatment composition (16) comprises a basic material, the basic material being LiOH, NaOH, KOH, RbOH, CsOH, Mg(OH).sub.2, Ca(OH).sub.2, Sr(OH).sub.2, Ba(OH).sub.2, Na.sub.2S, or tetramethylammonium hydroxide (TMAH).

5. The heating panel (10) according to claim 1, characterised in that the solidified wood treatment composition (16) comprises a heat conducting and heat retaining material and at least 10 wt % of a binder.

6. The heating panel (10) according to claim 5, characterised in that the heat conducting and heat retaining material is a metal salt, preferably an alkaline metal salt or alkaline earth metal salt, a silicate or silicate mineral, an oxide mineral, or ground rock made from igneous rock.

7. The heating panel (10) according to claim 5, characterised in that the binder comprises gypsum, magnesium sulphate, sodium sulphate, or waterglass.

8. A treatment apparatus (20) for treating wood material (22), comprising a hermetically sealable reaction space (24) configured for receiving the wood material (22) to be treated, characterised by further comprising heating panels (10) according to claim 1 arranged in the reaction space (24).

9. The treatment apparatus (20) according to claim 8, characterised in that it comprises a press device pressing together the wood material (22) to be treated arranged in the reaction space (24) and the heating panel (10).

10. The treatment apparatus (20) according to claim 8, characterised in that the reaction space (24) is surrounded by a thermal insulation member (26).

11. The treatment apparatus (20) according to claim 8, characterised in that a heating member (28) heating the reaction space (24) is arranged along a wall of the reaction space (24).

12. The treatment apparatus (20) according to claim 11, characterised in that the heating member (28) is arranged on a side wall, a ceiling, or a floor of the reaction space (24).

13. The treatment apparatus (20) according to claim 11, characterised in that the heating member (28) is the heating panel (10) according to claim 1.

14. A method for treating wood material, comprising subjecting the wood material (22) to be treated to heat treatment, characterised by further comprising the steps of bringing the wood material (22) to be treated into contact with the heating panel (10) according to claim 1, and providing the heat required for the heat treatment by heating the heating wire (14) arranged in the heating panel (10).

15. The method according to claim 14, characterised by arranging the wood material (22) to be treated between two heating panels (10).

16. The method according to claim 14, characterised by pressing together the wood material (22) to be treated and the heating panel (10).

17. The method according to claim 14, characterised by performing the heat treatment in a hermetically sealed reaction space (24), in the reaction space (24) of the treatment apparatus (20) according to claim 8 at a pressure that is lower than the atmospheric pressure.

18. The method according to claim 14, characterised by performing the heat treatment at a temperature of 20-300 C., preferably at a temperature of 100-220 C., for a duration of 6-48 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Preferred embodiments of the invention are described below by way of example with reference to the following drawings, where

[0035] FIG. 1 is a side view of a preferred embodiment of the heating panel according to the invention,

[0036] FIG. 2 is a sectional view of a preferred embodiment of the treatment apparatus according to the invention,

[0037] FIG. 3 is a detail view of another preferred embodiment of the treatment apparatus according to the invention,

[0038] FIG. 4A is a magnified side view of detail A of FIG. 3,

[0039] FIG. 4B is a magnified side view of detail B of FIG. 3, and

[0040] FIG. 5 is a sectional view of another preferred embodiment of the treatment apparatus according to the invention.

[0041] In the figures, components with like functions are denoted with the same reference numerals: however, their exact implementationfor example in different preferred embodimentsmay vary.

MODES FOR CARRYING OUT THE INVENTION

[0042] The heating panel 10 adapted for treating wood material 22 according to the invention comprises two parallelly arranged boundary members 12 having a shape that preferably corresponds to the shape of the wood material 22 to be treated, i.e., they preferably have a flat or curved configuration.

[0043] The heating panel 10 also comprises a heating wire 14 arranged between the two boundary members 12 that is preferably adapted for heating the wood material 22 to be treated that is brought into contact with the heating panel 10, i.e., subjecting it to a heat treatment.

[0044] The heating panel 10 further comprises a solidified wood treatment composition 16 that is arranged between the boundary members 12 and to surround the heating wire 14. The boundary members 12 are configured to allow the solidified wood treatment composition 16 to contact the wood material 22 to be treated. The boundary member 12 is preferably implemented as a perforated plate or grating that enables the solidified wood treatment composition 16 to contact the wood material 22 to be treated that is in contact with the heating panel 10. The boundary member 12 is preferably made of a heat-conducting material, for example metal, which improves heat transfer between the heating panel 10 and the wood material 22, thereby improving the heat treatment of the wood material 22.

[0045] The solidified wood treatment composition 16 preferably comprises a basic material, more preferably it comprises a strong base that has a swelling effect on the cellulose contained in the wood material 22. Strong bases are typically strong electrolytes that therefore dissociate completely. The basic material applied in the solidified wood treatment composition 16 can for example be LiOH, NaOH, KOH, RbOH, CsOH, Mg(OH).sub.2, Ca(OH).sub.2, Sr(OH).sub.2, Ba(OH).sub.2, Na.sub.2S, or tetramethylammonium hydroxide (TMAH) which are all regarded as strong bases. The solidified wood treatment composition 16 may preferably comprise known compounds applied for chemical cooking. It is preferable that the basic material applied in the solidified wood treatment composition 16 does not melt and does not decompose under 300 C. It is particularly preferable to include NaOH in the solidified wood treatment composition 16, as the melting point and boiling point thereof is 318 C. and 1390 C., respectively.

[0046] The solidified wood treatment composition 16 preferably further comprises a heat conducting and heat retaining material that can be preferably selected from among the following materials: [0047] various organic or inorganic salts, for example sulphates, chlorides, carbonates, acetates; salts of alkaline metals, for example sodium or potassium salts thereof; salts of alkaline earth metals, for example magnesium or calcium salts thereof; [0048] silicates, silicate minerals; [0049] oxide minerals, for example corundum (aluminium oxide), hematite (iron oxide), magnesium oxide; and [0050] ground rock made from igneous rocks, for example granite, basalt, or andesite.

[0051] Preferably, the melting point of the heat conducting and heat retaining material is also higher than 300 C., and it also does not decompose under a temperature of 300 C. The heat conducting and heat retaining material preferably does not react with other components of the solidified wood treatment composition 16.

[0052] Especially preferable heat conducting and heat retaining materials are sodium chloride (melting point: 801 C., boiling point: 1465 C.), potassium chloride (melting point: 776 C., boiling point: 1500 C.), or sodium acetate (decomposes at 324 C.).

[0053] The solidified wood treatment composition 16 preferably further comprises at least 10% of a binder, that is adapted to contribute to the solidification of the solidified wood treatment composition 16 (i.e., to keep it in one bulk), and prevents the solidified wood treatment composition 16 from falling out through the gaps and holes of the boundary members 12, for example, in the case of boundary members 12 implemented as perforated plates, through the perforations, and in the case of boundary members 12 implemented as gratings, through the gaps of the grating. The binder is preferably a mineral adhesive. The binder is preferably a material that is permeable to vapour and moisture, or optionally a material that can absorb and later release moisture. Preferably, the following materials can be applied as a binder gypsum (CaSO.sub.4), magnesium sulphate (MgSO.sub.4), sodium sulphate (Na.sub.2SO.sub.4), or waterglass (aqueous solution of sodium silicate).

[0054] A preferred composition of the solidified wood treatment composition 16 is set forth in the example below.

Example

[0055] 15 wt % of sodium hydroxide as a basic material, [0056] 70 wt % of sodium chloride as a heat conducting and heat retaining material, and [0057] 15 wt % of waterglass as a binder.

[0058] FIG. 1 illustrates a detail of a preferred configuration of the heating panel 10 according to the invention. The boundary members 12 of the heating panel 10 are arranged parallel to each other, and in the preferred embodiment according to FIG. 1 the boundary members 12 have a flat configuration, and three heating wires 14 are arranged between them in the detail shown in the figure, preferably at the same distance from each other. This arrangement facilitates a uniform heating (i.e., heat treatment) of the wood material 22 brought into contact with the heating panel 10. The heating wires 14 are preferably arranged at an identical distance from the boundary members 12, so in the arrangement according to the figure they are able to heat the wood material 22 to be heated, disposed above and under the heating panel 10, evenly, and to an identical extent. The heating wires 14 are preferably arranged inside a covering 18, wherein the covering 18 is preferably implemented as a tube, for example a metal tube, or a closed section having an arbitrary cross-sectional shape. The thickness of the heating panel 10, i.e., the distance between the boundary members 12, is preferably 10-100 mm. The length of the heating panel 10 is preferably 0.5-10 m, or preferably 1-5 m, and its width is preferably 0.2-5 m, or preferably 0.5-3 m. Smaller-sized heating panels 10 can even be moved without applying a lifting and/or moving apparatus, i.e., manually.

[0059] The boundary members 12 are preferably made from perforated sheet metal or grating, thereby enabling the solidified wood treatment composition 16 that is encompassed by the boundary members 12 and is arranged around the heating wires 14, and/or the covering 18 thereof to contact the wood material 22 to be treated that is brought into contact with the heating panel 10. Examples for preferred ways of contact between the wood material 22 to be treated and the heating panel 10 can be seen in FIGS. 2, 3, and 5.

[0060] The heating wires 14 are adapted for heating up the solidified wood treatment composition 16, that are able to directly heat, heat treat or dry the wood material 22 to be treated, and, if the applied boundary members 12 are made of a heat-conducting material, preferably metal, the solidified wood treatment composition 16 is also able to heat up the boundary members 12 that are also able to heat, heat treat or dry the wood material 22 to be treated.

[0061] The treatment apparatus 20 according to the invention, adapted for treating wood material 22, comprises a reaction space 24 configured for receiving the wood material 22 to be treated, and heating panels 10 arranged in the reaction space 24.

[0062] The treatment apparatus 20 preferably also comprises a press device adapted for pressing together the wood material 22 to be treated that is arranged in the reaction space 24 and the heating panel 10. The press device can preferably be a mechanical or hydraulic press.

[0063] In order to improve the heating and heat treatment of the wood material 22 to be treated, the reaction space 24 is preferably encompassed by thermal insulation members 26 that are adapted for reducing the heat loss of the reaction space 24.

[0064] Preferably, a heating member 28 adapted for heating the reaction space 24 is arranged along a wall (e.g., any bounding wall, for example a side wall, a ceiling and/or a floor) of the reaction space 24. The heating member 28 is preferably implemented as the heating panel 10 according to the invention.

[0065] FIG. 2 shows a sectional view of a preferred embodiment of the treatment apparatus 20 according to the invention. In the treatment apparatus 20 the heating panels 10 according to the invention and the wood material 22 to be treated are layered upon each other such that each piece of wood material 22 to be treated is arranged between two heating panels 10, and the wood material 22 to be treated is in contact with the boundary member 12 of the heating panel 10, and this way it is also in contact with the solidified wood treatment composition 16 of the heating panel 10.

[0066] In the treatment apparatus 20 according to FIG. 2, more than one pieces of wood material 22 are arranged in each layer, and the pieces in each layer are preferably having the same thickness, so the heating panels 10 are in contact with all of the pieces of wood material 22 of the given layer. The wood material 22 arranged in different layers may have different thicknesses. The wood material 22 can preferably be a trimmed or untrimmed board.

[0067] In the treatment apparatus 20 according to FIG. 2, the pieces of wood material 22 to be treated belonging to the same layer preferably do not contact each other, i.e., there is an air gap between the adjacently arranged pieces of wood material 22, through which the moisture extracted from the wood material 22 can be more easily discharged.

[0068] The size of the heating panels 10 applied in the treatment apparatus 20 preferably corresponds to the inside dimensions of the reaction space 24 of the treatment apparatus 20, i.e., the treatment apparatus 20 comprises one heating panel 10 for each layer. However, as can be seen in the preferred embodiment according to the figure, heating panels 10 of smaller size can also be applied, which can be tightly packed together. In the treatment apparatus 20 according to FIG. 2, four heating panels 10 are arranged in each layer, preferably in close contact with each other, and each heating panel 10 comprises two heating wires 14. In another preferred arrangement, the heating panels 10 are spaced apart from each other inside the layers, wherein the spacing between them is preferably 10-100 mm and is preferably the same as the thickness of the heating panel 10; this arrangement of the heating panels 10 preferably allows for more efficiently discharging the moisture extracted from the wood material 22. By applying smaller-sized heating panels 10, for example ones having a length of 1-2 m and a width of 20-100 cm, it has an advantage that the number and arrangement of the necessarily applied heating panels 10 can be changed flexibly, and that heating panels 10 with smaller size, and thus with lower mass, can be moved more easily (even manually), and they also allow for achieving better use of space in the reaction space 24.

[0069] The reaction space 24 of the treatment apparatus 20 can be preferably sealed hermetically, and a pressure lower than the atmospheric pressure can preferably be generated in the reaction space 24, which facilitates the extraction of moisture from the wood material 22. To improve the efficiency of moisture extraction, the treatment apparatus 20 can preferably also comprise a fan and/or an air heater.

[0070] The reaction space 24 of the treatment apparatus 20 is preferably enveloped by thermal insulation members 26 that preferably surround the reaction space 24 from all sides. In the preferred embodiment according to FIG. 2, the reaction space 24 is surrounded by two layers of thermal insulation members 26, thereby improving thermal insulation. The thermal insulation members 26 can be made of any thermal insulation material known from the prior art.

[0071] The treatment apparatus 20 preferably further comprises a heating member 28 that is preferably arranged along a wall of the reaction space 24, i.e., it is preferably arranged along a side wall, a ceiling, and/or a floor of the reaction space 24, and provides additional heating for the heat treatment of the wood material 22. The additional heating preferably contributes to providing a uniform temperature in the reaction space 24 of the treatment apparatus 20, and to equalizing occasional spatial differences in temperature, which provides that the entirety of the wood material 22 to be treated is at the same temperature, preferably also at such locations where it does not directly contact the heating panel 10. In the preferred embodiment according to FIG. 2, two respective heating members 28 are arranged along the walls and the floor of the reaction space 24. The heating member 28 can be implemented as any conventional component capable of heating, or the heating panel 10 can also be applied as a heating member 28. Preferably, such a panel can also be applied as a heating member 28 which does not comprise a solidified wood treatment composition 16, only heating wires 14.

[0072] In the preferred embodiment according to FIG. 2, the heating panels 10 and wood material 22 being stacked upon each other are arranged on a trolley 30 that can be preferably pushed into and pulled out from the reaction space 24. Thereby, the heating panels 10 and the wood material 22 can also be stacked upon each other and arranged outside the reaction space 24, followed by moving them into the reaction space 24. Instead of the trolley 30, another moving mechanism can also be applied, and the heating panels 10 and the wood material 22 can also be placed directly on the floor on the reaction space 24, or on a preferably fixed platform positioned thereon.

[0073] FIG. 3 shows a detail view of another preferred embodiment of the treatment apparatus 20 according to the invention. In this embodiment, the heating panels 10 are arranged vertically, and the wood material 22 to be treated is disposed between the vertically arranged heating panels 10. The heating panels 10 preferably comprise a bottom support member 31a and a top support member 31b that are adapted to ensure that the heating panel 10 is in a vertical position. The bottom support member 31a and the top support member 31b are preferably equipped with a moving mechanism that provides that the bottom support member 31a and the top support member 31b can move horizontally and thereby allows that the wood material 22 to be treated can be placed between the heating panels 10. The bottom support member 31a and the top support member 31b are preferably configured to comprise rollers. The configuration of the heating panels 10 preferably has the same features as were described above in relation to FIG. 1.

[0074] The position of the wood material 22 arranged between the heating panels 10 according to FIG. 3 can be fixed by applying a press device (not shown), or, alternatively, the wood material 22 can be affixed to a vertical support member 36. The vertical support member 36 is preferably also oriented vertically, and preferably comprises a fixing pin 38 (see FIG. 4B) adapted for securing the wood material 22. The vertical support member 36 can, on the one hand, be configured similarly to the bottom support member 31a and the top support member 31b of the heating panel 10, and, on the other hand, can have a configuration shown in FIG. 3, wherein the vertical support member 36 is affixed to a hanger member 32 via a coupling member 34. For a more detailed configuration of the hanger member 32 and the coupling member 34 see FIG. 4A. The hanger member 32 can be preferably moved along a guide member, for example a bar or rail, or can be hung on a hook that can be moved along a guide member. Accordingly, the wood material 22 affixed to the vertical support member 36 can be placed between the heating panels 10 and can be preferably pressed together therewith by applying a press device.

[0075] The wood material 22 to be treated is preferably arrangedfor example, fixed to the vertical support member 36in the treatment apparatus 20 according to FIG. 3 in a manner that corresponds to the growth and grain direction of the wood material 22 to be treated, i.e., the portion of the wood material 22 to be treated that originally lays closer to the roots is arranged at the bottom. It is of common knowledge that living trees have channels that transport water taken up by the tree from the roots towards the foliage. These channels are typically located in the sapwood (albumum) layer of the tree which surrounds in an annular manner the older, inner portion of the tree's body, the heartwood (duramen). As the tree gets older, the cells engaged in water transport die and are transformed into solid wood (heartwood), while the task of transporting water is taken over by a newly grown sapwood layer. Although the heartwood is no longer engaged in transporting water, water and other mineral materials are stored in the cell walls of the heartwood layer, for example in a bound state. The quantity of water stored in the heartwood layer preferably depends on the equilibrium values of various parameters (for example, pressure, temperature, etc.). In the case of the above-described preferred arrangement, the internal water (or optionally, nutrient) transport channels of the wood material 22 can be utilized in the course of the treatment process of the wood material 22 for discharging the water contained in the wood material 22 and the water vapour generated from the water under the effect of heat. During the wood treatment process, the water contained in the wood or the water vapour can be extracted along the channels of the wood material 22 with a lower flow resistance.

[0076] The treatment apparatus 20 according to FIG. 3 has the advantage that, thanks to the vertical (e.g., suspended) arrangement, the treatment apparatus 20 is able to perform a simultaneous treatment of a given quantity of wood material 22 in a reduced floor space, which reduces operating costs and improves space utilization.

[0077] FIG. 4A shows a magnified side view of detail A of FIG. 3, illustrating in more detail the interconnection of the hanger member 32, the coupling member 34, and the vertical support member 36. The features of the hanger member 32, the coupling member 34, and the vertical support member 36 are identical to the features explained in relation to FIG. 3.

[0078] FIG. 4B shows a magnified side view of detail B of FIG. 3. In FIG. 4B there can be observed the fixing pins 38 arranged on the vertical support member 36 that are adapted for fixing the wood material 22 to the vertical support member 36. The fixing pins 38 are preferably evenly spaced apart along the vertical support member 36.

[0079] FIG. 5 shows a sectional view of a further preferred embodiment of the treatment apparatus 20 according to the invention. The heating panels 10 and the pieces of wood material 22 to be treated, which are preferably pressed together by applying a press device (not shown in the drawing), are stacked with a vertical orientation beside each other also in the treatment apparatus 20 according to FIG. 5. In the embodiment according to FIG. 5, the heating panels 10 and the wood material 22 to be treated are rotated by 90 degrees with respect to the arrangement according to FIG. 3. The further structural components of the treatment apparatus 20 according to FIG. 5 and their features and alternatives are preferably identical to the structural components according to FIG. 3 and their features and alternatives.

[0080] The invention further relates to a method for treating wood material 22 comprising the step of subjecting the wood material 22 to be treated to heat treatment. In the course of the heat treatment process, the moisture content of the wood material 22 to be treated is removed in such a manner that it not only does not damage the wood material 22 but brings about advantageous changes in the wood material 22, for example increases the resistance and strength of the wood material 22. For performing the heat treatment, the wood material 22 to be treated is brought into contact with the heating panel 10 according to the invention, and the heat required for the heat treatment is at least partially provided by heating up the heating wire 14 disposed in the heating panel 10. By contacting the heating panel 10, the wood material 22 to be treated also comes into contact with the solidified wood treatment composition 16 of the heating panel 10. In the course of the method, the wood material 22 to be treated is preferably arranged between two heating panels 10, and, to prevent the deformation (warping) of the wood material 22 during the treatment, the wood material 22 and the heating panel 10 are pressed together. Heat treatment is preferably performed in a hermetically sealed reaction space 24, preferably in the reaction space 24 of the treatment apparatus 20 according to the invention, at a pressure that is lower than the atmospheric pressure, and preferably at a temperature of 20-300 C., more preferably at a temperature of 100-220 C., for a duration of 6-48 hours. The applied pressurethat is lower than the atmospheric pressure (i.e., underpressure)is preferably lower than the atmospheric pressure by at most 10,000 Pa.

[0081] At the preferred temperature of 100-220 C. the bound and free water content of the wood material 22 to be treated is transformed into vapour or steam and is thus able to leave the wood material 22, for example by diffusing from the intercellular space towards the surface of the wood material 22. Water condensing on the surface of the wood material 22 is also transformed into water vapour. When the temperature is raised above 100 C., a superheated, saturated, wet steam space is produced in the reaction space 24, in which the ratio of water and vapour can be adjusted, and the equilibrium of water and vapour can be maintained and controlled by controlling the pressure inside the reaction space 24. With raising external temperature and raising the temperature of the wood material 22, the fibre saturation limit decreases, and thereby the equilibrium moisture content of the wood material 22 is also reduced, which urges the water to leave the wood material 22. The moisture content of the medium, e.g., air or gas, surrounding the wood material 22 can be adjusted by quickly removing the generated vapour, and also by the introduction of a dry medium. These actions change the partial pressure of the vapour in the wood material 22, which results in water and water vapour being extracted from the wood material 22, thereby contributing to the drying of the wood material 22.

[0082] It is preferred to increase the temperature of the wood material 22 to be treated gradually (i.e., in stages) during the process, which contributes to a gentle treatment and drying of the wood material 22 and reduces the occurrence of tensions in the wood material 22 and the chance of warping of the wood material 22.

[0083] By applying pressure control, it is also possible to prevent a vapour explosion from occurring in the wood material 22, for example in the wood fibres thereof. In order to maintain an equilibrium, water supplied preferably from an external source can be injected to the reaction space 24 in addition to applying pressure control.

[0084] In order to introduce the solidified wood treatment composition 16 of the heating panel 10 into the wood material 22, it is preferred to intermittently increase the humidity, even to 100%, more preferably to apply a slight overpressure, preferably an overpressure of at most 10,000 Pa. Pressure can be controlled for example by applying a fan and/or air heater arranged in the treatment apparatus 20.

[0085] The method may optionally comprise a preparation, for example cutting to size or trimming of the wood material 22.

[0086] In the course of performing the treatment method, the heat treatment can preferably also be carried out according to a predetermined program, for example a temperature-time function.

[0087] The treatment method is preferably performed in a low-oxygen environment. To provide such an environment, the reaction space 24 of the treatment apparatus 20 is filled with a protective gas, which protective gas is for example nitrogen, carbon dioxide, or a mixture thereof. The advantage of low-oxygen environments is that the spontaneous ignition or self-ignition of the wood material 22 can be prevented.

[0088] In the course of the method according to the invention the relative moisture content of the wood material 22 can be reduced under 5% by the end of the treatment process. The moisture content of the wood material 22 is preferably continuously being measured and monitored during the course of the treatment process, and the predetermined heat treatment program can be modified based on the measured data.

[0089] During the treatment method according to the invention, the pressure of the reaction space 24 is controlled preferably according to a predetermined pressure profile, which pressure profile contains pressure values that are higher than the atmospheric pressure by at most 10,000 Pa and are lower than the atmospheric pressure by at most 10,000 Pa. The pressure of the reaction space 24 of the treatment apparatus 20 is preferably being monitored during the whole course of the treatment process, preferably by using pressure sensors arranged in the reaction space 24. In a preferred embodiment of the invention, the predetermined pressure profile provides that a predetermined pressure value is maintained, wherein the predetermined pressure value is for example the atmospheric pressure: the pressure sensors can also be applied for monitoring and maintaining this predetermined pressure value.

[0090] The manner of industrial application of the invention follows from the features of the technical solution according to the disclosure above. As can be seen from the description above, the invention achieves its objectives in a very advantageous manner compared to the prior art. The invention is, of course, not limited to the preferred embodiments described in detail above, but further variants, modifications and developments are possible within the scope of protection determined by the claims.

LIST OF REFERENCE SIGNS

[0091] 10 heating panel [0092] 12 boundary member [0093] 14 heating wire [0094] 16 solidified wood treatment composition [0095] 18 covering [0096] 20 treatment apparatus [0097] 22 wood material [0098] 24 reaction space [0099] 26 thermal insulation member [0100] 28 heating member [0101] 30 trolley [0102] 31a bottom support member [0103] 31b top support member [0104] 32 hanger member [0105] 34 coupling member [0106] 36 vertical support member [0107] 38 fixing pin