Wood drying facility

Abstract

To provide a wood drying facility capable of shortening the drying period while maintaining the same luster, fragrance, stickiness, wood grain and humidity control function as in the case of natural drying. [Solution] A wood drying facility 1 comprising a floor 21, walls 22, 23, 24 erected on the floor 21, a roof 25 supported by the walls 22, 23, 24, and a wood entrance 26 to which an opening / closing body 5 is attached, and in which a drying chamber 2 is formed by the floor 21, the walls 22, 23, 24, the roof 25, and the opening / closing body 5, and in which at least the walls 22, 23, 24, the roof 25, or the opening / closing body 5 have multiple solid wood pieces (humidity-regulating material 8) with end faces on both ends incorporated therein, one of the end faces facing the inside of the wood drying facility 1 and the other end face facing the outside of the wood drying facility 1, and preferably the wall parts 22, 23, the roof part 25, or part of the opening / closing body 5 that face the outside air are formed from vinyl.

Description

[Technical field]

[0001] This invention relates to a wood drying facility, and more particularly to a wood drying facility that utilizes the moisture-regulating function of solid wood. [Background technology]

[0002] Wood used as an industrial material is required to have functions or properties such as ease of processing, resistance to warping, cracking, and shrinkage. In today's industrialized world, there is a demand for uniform and standardized mass production of wood with these functions in a short period of time. Wood-based materials developed against this background include laminated lumber, plywood, and MDF.

[0003] By the way, immediately after felling, wood fibers contain a large amount of moisture. Therefore, when wood is used as a material for buildings, furniture, etc., it is necessary to carry out a drying process to prevent cracks and deformation due to shrinkage. In recent years, with the progress of industrialization, artificial drying technology that uses dryers to complete drying in a short period of time has been widely used.

[0004] There are various methods for artificial drying, including high-temperature and high-frequency methods. High-temperature methods use heavy oil or other materials to raise the temperature inside the drying chamber to 100-130°C, removing moisture from the wood cells. This method achieves high drying results in a shorter period of time than natural drying and is effective in preventing cracks on the wood surface, but it has drawbacks such as destroying internal cells and discoloring the wood surface, making it difficult to reuse wood that has been artificially dried.

[0005] In this regard, Patent Document 1 is known as a technology relating to so-called low-temperature drying of wood. This technology aims to maintain the temperature inside the drying chamber at 30 to 50°C by assembling heat storage panels filled with natural ore (zeolite processed into granules) from front to back, left to right, top to bottom to form a low-temperature drying chamber, in which heat is stored in the natural ore by a stove installed inside the chamber, and far-infrared rays are emitted from the natural ore, making it possible to uniformly dry wood and other materials placed inside the chamber at a low temperature. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4712120 Summary of the Invention [Problem to be solved by the invention]

[0007] Wood that has been dried at high temperatures does not show any noticeable cracks on the outside, and is also less likely to warp or crack during use. However, during the high-temperature drying process, essential oils, aromatic components, insect and mold repellents, and sticky components bubble and boil out of the wood's ends along with moisture, causing the fibers inside to stand out and crack easily, leaving concerns about the wood's toughness. In addition, the wood's unique scent is lost and replaced with a charcoal-like smell, and the wood's cells are destroyed, resulting in the loss of the wood's natural luster, gloss, and moisture-regulating properties. In addition, there is concern that the carbon dioxide stored in the wood is released during the high-temperature drying process, which could contribute to global warming.

[0008] In contrast, solid wood that has been naturally dried does not go through a high-temperature drying process, so the cells are not broken down and the wood's natural fragrance, luster, toughness, and moisture-regulating properties are maintained. It also helps prevent global warming by reducing carbon dioxide emissions. Unlike plywood and other materials that are produced using adhesives, solid wood is free of the harmful effects of adhesives, and when used as a building material, it creates a space where you can breathe deeply in peace, providing a highly soothing effect. If used as solid wood, it can be recycled into building materials or repurposed into furniture materials, making it highly recyclable.

[0009] However, natural drying requires a drying period of several months, so in today's industrialized world, there is a demand for new low-temperature wood drying facilities that can shorten the drying period while retaining the benefits of natural drying.

[0010] In this regard, the technology disclosed in Patent Document 1 is a technology related to low-temperature drying of wood, like the present invention, but it is said that a building needs to be constructed to surround the low-temperature drying chamber made of the above-mentioned heat storage panels (see paragraphs 0008 and 0011, and Fig. 1), and a stove that uses fossil fuels needs to be installed inside, resulting in high installation costs and running costs. In addition, it is a complex structure in that it is necessary to construct the heat storage panels using natural ore, a material different from wood, and it is not a general-purpose technology.

[0011] The present invention has been made in consideration of the above problems, and aims to provide a wood drying facility that can shorten the drying period while maintaining the same luster, fragrance, toughness, wood grain, and moisture-regulating function as when the wood is naturally dried. [Means for solving the problem]

[0012] The wood drying facility of the present invention comprises a floor, walls erected on the floor, a roof supported on the walls, and a wood entrance to which an opening and closing body is attached, and the floor, walls, roof and opening and closing body together form a drying chamber, and is characterized in that at least one of the walls, roof or opening and closing body has a plurality of solid wood pieces with end faces on both ends incorporated therein, one of which faces the inside of the drying chamber and the other end face faces the outside of the wood drying facility.

[0013] The wood drying facility may be characterized in that at least the wall portion facing the outside air, the roof portion, or a part of the opening and closing body is made of vinyl.

[0014] The wood drying facility may also be characterized in that the opening and closing body is a sun-shaped frame body, the solid wood is a square timber, the vinyl is attached so as to cover an upper opening of the frame body, and a plurality of the solid wood pieces are fitted into a lower opening of the frame body so as to block the lower opening.

[0015] Furthermore, the wood drying facility may have a boiler that heats air using wood-based materials as fuel, a supply side duct having one end connected to the output side of the boiler and the other end arranged above the drying chamber, and supplying heated air to the upper side of the drying chamber, and a suction side duct having one end connected to the input side of the boiler and the other end arranged below the drying chamber, and drawing air inside the drying chamber from below the drying chamber. Effect of the Invention

[0016] According to the present invention, it is possible to provide a wood drying facility that can shorten the drying period while maintaining the same luster, fragrance, toughness, wood grain, and moisture-regulating function as when the wood is naturally dried. [Brief description of the drawings]

[0017] [Figure 1] This is a simplified diagram showing the configuration of the wood drying facility 1 of the present invention, viewed from the front side, which is the wood entrance 26 side for the material W to be dried, and in particular, the sliding door 5B and the front wall surface of the boiler room 3 are omitted in order to show the internal structure. [Diagram 2] FIG. 2 is a front view of the exterior of the wood drying facility shown in FIG. 1. [Diagram 3] 2A and 2B are diagrams showing the configuration of an opening / closing body 5, in which (A) is a front view and (B) is a cross-sectional view taken along line AA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The wood drying facility of the present invention will be described in detail below, but the embodiments of the present invention are not limited to these. In the drawings, the same members or parts are given the same reference numerals and duplicated explanations are omitted. The dimensions and ratios of each part shown in the drawings are merely examples and can be changed as appropriate without changing the gist of the present invention.

[0019] Generally, in order to distribute wood as a building material that is less likely to warp or crack, it is said that the moisture content must be reduced to about 20% to about 25% or less, but with the wood drying facility of this invention, wood after being cut and shaped into a desired shape (hereinafter referred to as "wood to be dried") can be dried to a moisture content (weight moisture content) of approximately 20% or less. In addition, the wood drying facility of this invention is equipped with a drying room that utilizes the heat of the sun and the moisture-regulating properties of wood, and can dry wood while retaining the original scent, luster, toughness, and moisture-regulating properties of wood.

[0020] This wood drying facility is a wood drying facility that includes a floor, a wall that stands on the floor, a roof that is supported by the wall, and a wood entrance to which an opening and closing body is attached, and the floor, wall, roof, and opening and closing body form a drying chamber. At least one of the wall, roof, or opening and closing body is fitted with a plurality of solid wood pieces with end faces at both ends, with one end face facing the inside of the wood drying facility and the other end face facing the outside of the wood drying facility. The humidity control function of the solid wood can shorten the drying period. At least a portion of the wall, roof, or opening and closing body is made of vinyl. The heat from the sun is taken into the drying chamber through the vinyl, thereby raising and maintaining the temperature inside the drying chamber.

[0021] In order to give the material to be dried the same luster, fragrance, toughness, wood grain, and moisture-regulating properties as if it had been naturally dried, the drying temperature in the drying chamber is set to a range of 40 to 45°C. Based on the knowledge of the inventors of the present application, the upper limit temperature in the drying chamber is set to about 45°C, which is considered to be the limit temperature at which many organisms on Earth can survive. The floor, walls, and roof are made of wood or vinyl. Wood has a low specific gravity and is not easily conductive to heat, so it is expected to have an insulating effect.

[0022] Next, the configuration of a wood drying facility 1 according to an embodiment of the present invention will be described with reference to the drawings. The wood drying facility 1 is roughly composed of a drying chamber 2 and a boiler room 3 in which a boiler 31 is installed. The air in the drying chamber 2 is heated primarily by solar heat, and the boiler 31 is operated secondarily when solar thermal energy alone is insufficient, such as in winter or on cloudy days. As shown in Figs. 1 and 2, the drying chamber 2 and the boiler room 3 may be formed by dividing a single building with a partition wall 24, or they may be separate buildings connected to each other by ducts 4a and 4b.

[0023] In this embodiment, the drying chamber 2 is one room, but the building may be divided into several rooms to provide several drying chambers. By providing several drying chambers, several pieces of wood to be dried that have different drying start times and drying periods can be processed in parallel. As one design example, the wood drying facility may have a total width of about 36 meters, a depth of about 4 meters, and a height of about 4 meters, and the interior may be divided into six drying chambers, each of which may be fitted with an opening and closing body, which will be described later, so that the wood to be dried can be carried in and out and dried separately for each drying chamber.

[0024] As shown in FIG. 1, the drying chamber 2 has a horizontally long box shape and is composed of a wooden floor 21, wooden walls 22, 23, and 24 erected on three sides of the floor 21, a wooden roof 25 supported by the walls 22, 23, and 24, and an opening / closing body 5. The wall 24 arranged on the right side in a front view also serves as a partition wall separating the drying chamber 2 from the boiler chamber 3. The drying chamber 2 is composed of the walls 22, 23, and 24 which are fixed on three sides, and the remaining side is open to form a wood inlet 26. A movable opening / closing body 5 is attached to this wood inlet 26 so as to be freely opened and closed. When the opening / closing body 5 is closed, it constitutes one side of the drying chamber 2, and the interior of the chamber is in a closed state. A thermometer (not shown) is attached to the drying chamber 2 to measure the temperature inside the drying chamber 2.

[0025] The opening / closing body 5 of this embodiment is composed of a pair of sliding doors 5A and 5B, which open and close like a sliding door. In other words, the pair of sliding doors 5A and 5B are double sliding doors. Since the sliding doors 5A and 5B have the same characteristics, the configuration of the sliding door 5A will be described, and the configuration of the sliding door 5B will be given the same reference numerals and will not be described. Note that the above configuration of the opening / closing body is merely an example, and the opening / closing body may be composed of one sliding door with a part of the side where the wood entrance 26 is provided as a fixed wall, or may be composed of three or more sliding doors. Instead of a sliding type opening / closing body like a sliding door, the opening / closing body may be composed of a door that is supported by a hinge and opens and closes like a double door with the hinge as a rotation axis.

[0026] As described later, the sliding doors 5A and 5B are fitted with multiple square solid wood pieces (hereinafter referred to as "humidity control materials 6") and are quite heavy. Therefore, in order to facilitate the opening and closing of the sliding doors 5A and 5B, it is preferable to provide rails along the opening and closing direction so that the sliding doors 5A and 5B can slide along the rails.

[0027] The materials to be dried W are stacked in battens on the floor 21 of the drying chamber 2. Specifically, the sliding doors 5A, 5B are operated to open the wood entrance 26, and the materials to be dried W are stacked by operating a forklift or the like, with spacers between each batten to allow air to pass through.

[0028] The temperature inside the drying chamber 2 is preferably raised or maintained by taking in solar heat into the chamber. As described above, the drying temperature inside the drying chamber 2 is set to a range of 40 to 45°C. Therefore, when solar heat alone is insufficient, the boiler 31 described below is operated.

[0029] The opening / closing body 5 is a sun-shaped frame body and is composed of a pair of left and right vertical plates 51, 52 arranged at a regular interval and extending parallel to the up and down direction, a pair of upper and lower horizontal plates 53, 54 connected to the upper and lower ends of the vertical plates 51, 52 respectively and extending parallel to the horizontal direction, and a middle plate 55 arranged parallel to the horizontal plates 53, 54 and with each end connected at a right angle to the middle of the vertical plates 51, 52.

[0030] The vertical plates 51, 52, the horizontal plates 53, 54 and the middle plate 55 are plate materials having approximately the same constant width, and are fixed to each other so that the opening / closing body 5 has a constant thickness (in this embodiment, a length approximately the same as the longitudinal dimension of the humidity control material 6) as shown in Fig. 3(B). Translucent vinyl 7 is attached to the front and back sides of the upper opening defined by the middle plate 55 so as to cover the upper opening.

[0031] The vinyl 7 was inspired by vinyl greenhouses that have a warming effect, and by covering the upper opening with the vinyl 7, the heat of the sun is taken in and the temperature rises inside the room. In this embodiment, the vinyl 9 is attached only to a part of the opening and closing body 5, but a part of the wall parts 22, 23, 24 that face the outside air (the wall parts that form the drying chamber 3 and become the outer wall surfaces of the wood drying facility 1) and a part of the roof part 25 may be made of vinyl, and such a configuration allows more solar heat to be taken in inside the drying chamber 2. For example, pillars may be erected at the four corners of the floor surface, and vinyl may be attached to these pillars to form vinyl side walls.

[0032] The humidity-regulating materials 6 are square solid wood pieces cut to roughly the same dimensions. The humidity-regulating function of the solid wood absorbs moisture in the drying chamber 2 and releases it to the outside. As mentioned above, solid wood is used because high-temperature dried wood has broken down cells and its humidity-regulating effect is almost nonexistent. According to the knowledge of the inventors of this application, the humidity-regulating effect works better in the direction in which the vessels and tracheids, through which moisture and nutrients move, extend.

[0033] Based on this knowledge, both ends of each humidity control material 6 are formed by cutting the wood grain direction at a substantially right angle, and the humidity control materials 6 are fitted into the lower opening of the frame so that one of the ends faces the inside of the drying chamber 2 and the other faces the outside of the wood drying facility 1. The humidity control materials 6 are square, and as shown in the figure, they are fitted in a lattice pattern so as to block the lower opening and to minimize gaps between the humidity control materials 6. When fitted in this way, as shown in the figure, each end appears like a tile when viewed from the front. Although not shown, the other end is similar.

[0034] The humidity-regulating material 6 is made of solid wood and has a humidity-regulating function of taking in moisture when the surrounding humidity is high and releasing the moisture inside into the air when the surrounding humidity is low. The moisture content of wood immediately after felling is, for example, about 150%, and the humidity on the drying chamber 2 side where the materials W to be dried are stored is higher than the outside air side (outside the wood drying facility 1). Therefore, the moisture inside the drying chamber 2 is taken into the interior of the humidity-regulating material 6 from one end side, passes through the internal tissue of the humidity-regulating material 6 such as vessels, and is released to the outside from the end grain surface on the opposite side. Due to the humidity-regulating function of the humidity-regulating material 6, the humidity inside the drying chamber 2 gradually decreases.

[0035] In this embodiment, the humidity control materials 6 are arranged so that their end grain faces are flush, but this is not limited to this, and the humidity control materials may be arranged so that their longitudinal dimensions are different or they are offset in the longitudinal direction, so that their end grain faces appear uneven. The widths of the vertical boards 51, 52, the horizontal boards 53, 54, and the middle board 55 are set to be equal to the longitudinal dimensions of the humidity control materials 6 in the illustrated example, but this is not limited to this.

[0036] In order to increase the humidity control capacity within the drying chamber 2, in addition to the opening and closing body 5, multiple humidity control materials with end grain surfaces at both ends may be incorporated into the walls 22, 23 and roof 25 so that one of the end grain surfaces faces the inside of the drying chamber 2 and the other end grain surface faces the outside of the wood drying facility 1. For example, a rectangular opening (not shown) may be provided in part of the walls 22, 23, and multiple pieces of the above-mentioned rectangular humidity control materials may be fitted into this opening so as to cover the opening.

[0037] The boiler room 3 is surrounded by walls on all four sides, and a wood chip-fired boiler is installed on the floor as the boiler 31 that heats air using wood-based materials as fuel. A door (not shown) is provided on one of these walls for the installation, operation and maintenance of the boiler 31. The partition that separates the drying room 2 and the boiler room 3 is the wall 24, and the upper and lower parts of the wall 24 are provided with through holes for attaching the ducts 4a and 4b. The upper through hole is fitted with a supply duct 4a, one end of which is connected to the output side of the boiler 31 and the other end of which is disposed on the upper side of the drying room 2, and which supplies heated air to the upper part of the drying room 2. The lower through hole is fitted with a suction duct 4b, one end of which is connected to the input side of the boiler 31 and the other end of which is disposed on the lower side of the drying room 2, and which draws air inside the drying room from the lower part of the drying room 2.

[0038] Air heated by the boiler 31 is introduced into the drying chamber 2 through the upper supply duct 4a, and heavy, humid air from the drying chamber 2 flows into the boiler 31 through the lower suction duct 4b. When the boiler 31 is operating, the air in the drying chamber 2 circulates between the drying chamber 2 and the boiler 31. Note that other types of boilers may be used as the heat source, but in the case of wood chip burning, wood materials such as precut scraps generated in lumber factories can be used as fuel. Note that a blower fan may be installed on the ceiling of the drying chamber for forced ventilation.

[0039] Next, a method of using the wood drying facility 1 and the effects of the present invention will be described. First, the sliding doors 5A and 5B of the opening / closing body 5 are slid to open the wood entrance 26, and the wood W to be dried that has been processed into a desired shape is brought into the drying chamber 2. The humidity-regulating material 6 is fitted into the lower opening of the opening / closing body 5, so it moves together with the opening / closing body 5 when it is slid. Next, the sliding doors 5A and 5B of the opening / closing body 5 are slid to close the wood entrance 26, and the drying chamber 2 is made to be in a closed state.

[0040] During the summer, when temperatures rise and the hours of sunlight are long, it may be possible to heat and maintain the temperature of the drying chamber 2 using only the heat from the sun taken in through the vinyl 7 during the day without operating the boiler 31, but when it is necessary to heat the room quickly, on cloudy days, or during the winter, the boiler 31 is operated as an auxiliary heat source to maintain the temperature within the above range inside the drying chamber 2. The air heated by the boiler 31 flows into the drying chamber 2 through the upper supply duct 4a and is collected by the boiler 31 through the lower suction duct 4b.

[0041] The humidity inside the drying chamber 2 becomes higher than the humidity outside due to the moisture dissipated from the material W to be dried. Therefore, the moisture inside the drying chamber 2 is released to the outside through the moisture-regulating material 6 due to the moisture-regulating effect of the moisture-regulating material 6. More specifically, the moisture inside the drying chamber 2 is mainly absorbed from the end grain surface on the indoor side, passes through the inside of the moisture-regulating material 6, and is released from the end grain surface on the outdoor side. This moisture-regulating function promotes drying and shortens the drying period. When the moisture content falls below the desired value, the wood entrance 26 is opened and the material W to be dried is removed.

[0042] By keeping the temperature in the drying chamber 2 within the above range, it is possible to proceed with drying while retaining the same luster, fragrance, stickiness, wood grain, and moisture-regulating properties as when natural drying is performed, and high-quality dried lumber can be obtained. The wood can be dried and shipped as solid wood without adding adhesives, and without killing the wood cells at high temperatures. The heat from the sun (natural energy) is used to raise the temperature without using any extra energy, and the moisture-regulating properties of the wood are used to shorten the drying period, so the energy costs and equipment costs for drying lumber can be significantly reduced. According to experiments conducted by the inventors of this application, the moisture content of American pine horn can be reduced to about 20% in one month.

[0043] The present invention is not limited to the above embodiment, and can be modified as appropriate as long as it has the characteristics of the present invention. For example, the boiler 31 may be automatically controlled based on the temperature measurement data in the drying chamber 2 so that the temperature in the drying chamber is kept within the above temperature range. [Industrial Applicability]

[0044] The wood drying facility of the present invention is preferably used for drying wood after it has been felled and processed into lumber, but is not limited to this use. [Explanation of symbols]

[0045] 1. Wood drying facility 2 Drying room 21 Floor 22 Wall 23 Wall 24 Wall 25 Roof 26 Timber entrance 3. Boiler Room 31 Boiler 4a Supply duct 4b Suction duct 5 Opening and closing body 5A Sliding door (opening and closing body) 5B Sliding door (opening and closing body) 51 Vertical Board 52 Vertical Board 53 Horizontal board 54 Horizontal board 55 Middle plate 6. Humidity control material (solid wood) 7. Vinyl W Material to be dried

Claims

1. A wood drying facility comprising a floor, a wall erected on the floor, a roof supported by the wall, and a wood entrance to which an opening and closing body is attached, the floor, the wall, the roof, and the opening and closing body forming a drying chamber, At least one of the wall portion, the roof portion, or the opening and closing body is provided with a plurality of solid wood pieces having end faces at both ends, one of the end faces facing the inside of the drying chamber and the other end face facing the outside of the wood drying facility. A wood drying facility characterized by:

2. At least the wall portion facing the outside air, the roof portion, or a part of the opening and closing body is made of vinyl.

2. The wood drying facility according to claim 1 .

3. The opening and closing body is a frame body in a square shape, and the solid wood is a square timber, The vinyl is attached so as to cover the upper opening of the frame body, The plurality of solid wood pieces are fitted so as to close the lower opening of the frame body.

3. The wood drying facility according to claim 2.

4. A boiler that heats air using wood-based materials as fuel; a supply side duct having one end connected to an output side of the boiler and the other end disposed above the drying chamber, the supply side duct supplying heated air to the upper portion of the drying chamber; a suction side duct having one end connected to the input side of the boiler and the other end disposed on the lower side of the drying chamber, for sucking air from the lower side of the drying chamber into the drying chamber; 4. The wood drying facility according to claim 1 or 3.

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