JP5484237B2 - How to dry wood - Google Patents

Description

  The present invention relates to a method for drying wood.

As domestic structural materials such as pillar materials, domestically-produced cedar and hinoki core-supported square materials such as cypress have been used. Increased. However, such a cored square member is liable to be cracked during drying, and similarly to the back split material, the dimensional stability after construction and construction is poor, which causes a problem. For this reason, the use of laminated wood having excellent dimensional stability is also increasing.
In recent years, a high-temperature drying method has been developed and spread to prevent cracking of the material surface that occurs during drying of cedar and cypress cored squares. In this high temperature drying method, it is said that the surface cracking is reduced by forming a drying set on the surface layer by drying at a dry bulb temperature of 120 ° C. in the initial stage of drying. According to the high temperature drying method, cracks on the surface of the material are relatively reduced, but it is not sufficient.

Further, the high temperature drying method has a problem that internal cracks are likely to occur. Internal cracks in the high-temperature drying method are considered to occur when the material surface layer is set to be dried in a tensile state, and thus the interior of the material cannot be freely contracted and the tensile stress increases.
In addition, cracking of the material surface is considered to occur in the initial stage of high-temperature drying, when the duration of the dry-bulb temperature of 120 ° C is not sufficient, the so-called drying set formation layer is shallow and tensile stress is still present on the surface layer. ing.
In order to prevent cracking of the material surface, if the duration of the dry bulb temperature of 120 ° C. is excessively increased, the layer of the drying set is deepened, but the drying speed is fast, so that the portion inside the surface of the drying set layer is 120. It is said that due to the dry bulb temperature of 0 ° C., a part of the inner layer starts to shrink rapidly, and the inner layer part is strongly restrained by the surface drying set, so that the tensile stress increases and an internal crack occurs.

  As a drying schedule control method for reducing such material surface cracks and internal cracks, a method of proceeding drying while measuring the temperature and moisture content in the wood (see Patent Document 1) is known. In addition, the applicant of the present invention is a method of proceeding with drying while controlling drying conditions based on data obtained from strain detection means fixed inside the wood (see Patent Document 2), and two adjacent sides of a square bar. A method of advancing drying while fixing a pair of displacement gauge fixing jigs and measuring a displacement generated during drying with a displacement gauge fixed between the pair of displacement gauge fixing jigs (see Patent Document 3) Etc. were proposed.

  Further, as an artificial drying method for physically reducing material surface cracking and / or internal cracking, a technique of drying while constraining the outer periphery of wood with moisture permeable shrinkage restraining means (see Patent Document 4), or a wood mouthpiece A technique (see Patent Documents 5 and 6) for making a hole in a portion is known.

JP 2001-287206 A JP 2004-190957 A JP 2007-120902 A Japanese Patent Laid-Open No. 02-050072 Japanese Patent Laid-Open No. 02-155605 JP 2007-196507 A

  According to the methods of Patent Documents 1 to 3, it is possible to effectively prevent internal cracks and material surface cracks for wood with strain detection means, temperature and moisture content sensors, displacement gauges, and the like. When wood is placed in a dryer and dried at the same time, the moisture content of the wood often varies, making it difficult to perform appropriate drying control for each of the multiple woods having different moisture contents. It was difficult to manage the whole of a plurality of wood (drying material lot) to be dried.

  Moreover, although the method of patent documents 4-6 is recognized to some extent in the crack prevention effect, the operation | work which mounts a shrinkage | contraction restraining means so that the outer periphery of to-be-dried wood may be surrounded is complicated, or processing such as making a hole. It is labor-intensive and costly, such as the need to introduce additional dedicated machines.

Therefore, the objective of this invention is providing the drying method of the timber which can find the drying conditions which can suppress an internal crack.
Moreover, the objective of this invention is providing the drying method of the timber which can dry timber efficiently, suppressing an internal crack.

  The present invention relates to a method for drying wood by artificially drying the timber in a state where the lip of the timber is partially covered with a shield, and the lip is connected between the midpoints of opposite sides. A section that is divided into four areas by the center line of the book, and the area closest to the edge of the end face of the outermost ring when the outermost ring that does not reach any of the two adjacent sides is viewed in each area. Provided with a method of drying wood that artificially drys the wood without covering the vicinity of the inside of the outermost annual ring with the shield while covering the inside of the outermost ring of the outermost ring where the diagonals of the facets intersect with each other. By doing so, the above-mentioned object has been achieved (hereinafter, the first invention is referred to as this invention).

  The present invention is a method of drying wood by artificially drying the timber in a state in which the timber surface of the wood is partially covered with a shield, and the culvert surface is arranged near the midpoint of each side of the lip surface. By providing a method for drying wood, in which artificial drying of wood is performed in a state where one or a plurality of annual rings covered by the shield are not covered on the diagonal line of the mouthpiece surface while being covered with the shield. The object has been achieved (hereinafter, the second invention refers to this invention).

  The present invention is a method of drying wood by artificially drying the timber in a state where the lip of the timber is partially covered with a shield, wherein the lip is divided into three equal parts and is square. When divided into nine regions, the ratio of the area covered with the shielding in the corner region located at the four corners of the mouthpiece surface is the shielding in the outer peripheral central region located between two adjacent corner regions. The above object is achieved by providing a wood drying method for artificially drying wood so as to be smaller than the ratio of the covered area (hereinafter referred to as the third invention when referred to as the third invention). ).

  The present invention relates to a mouthpiece surface shielding tool used for artificially drying the wood in a state where the wood mouth surface is partially covered, and a plate-like shielding portion having an opening in the center, and the mouth end surface Fixing means for fixing the shielding tool in a state where the shielding part is in contact with the end of the wood, a square-shaped hole is formed in the shielding part, the area of the opening is The present invention provides a mouthpiece surface shielding tool that is 30 to 50% of the area of the mouthpiece surface (hereinafter referred to as the fourth invention).

According to the wood drying method of the present invention, it is an object to provide a wood drying method capable of finding a drying condition capable of suppressing internal cracks.
Moreover, according to the wood drying method of the present invention, wood can be efficiently dried while suppressing internal cracks.

It is a schematic diagram which shows an example of the drying apparatus of the wood which can be used for implementation of this invention. It is a perspective view which shows an example of a wooden-surface shield. It is the III-III sectional view taken on the line of FIG. It is a perspective view which shows a mode that the wooden-surface shield of FIG. 2 is attached to the wooden-mouth part of wood. It is a figure which shows the other example of a wooden end surface shielding tool, (a) Perspective view, (b) It is sectional drawing. It is a perspective view which shows a mode that the wooden-surface shield of FIG. 5 is attached to the wooden-mouth part of wood. It is a perspective view which shows the other example of a wooden end surface shielding tool. It is explanatory drawing for demonstrating the shielding aspect of the preferable end face of this invention. It is explanatory drawing for demonstrating the shielding aspect of the other preferable facet of this invention. It is explanatory drawing for demonstrating the shielding aspect of the other preferable mouth end surface of this invention. It is a figure which shows the arrangement | positioning aspect of the shielding part (black coating part) of a front end. It is a graph which shows a drying schedule.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
It is preferable to use the drying apparatus provided with the drying chamber which can control temperature and humidity for implementation of the drying method of the wood of this invention.
FIG. 1 shows an example of such a drying apparatus, which includes a drying chamber 1 capable of controlling the temperature and humidity, and a wood 10 accommodated in the drying chamber 1 having a temperature and humidity in the drying chamber 1. Can be dried under control.

  More specifically, the wood drying apparatus of FIG. 1 includes a drying chamber 1 that houses the wood 10 to be dried, a vaporization mechanism 2 that injects steam into the drying chamber 1, and the air in the drying chamber 1. A heating mechanism 3 that heats the air, an air supply mechanism 4 that introduces outside air into the drying chamber 1, and an exhaust mechanism 5 that exhausts the air in the drying chamber 1 to the outside.

  The steaming mechanism 2 is configured to introduce steam generated in a steam generating device (boiler or the like) 21 into the drying chamber 1 through a steam introduction pipe 22 connected to the drying chamber 1. Steaming into the drying chamber can be controlled by opening and closing a control valve 23 such as an electromagnetic valve or an electric valve provided in the introduction pipe 22. The heating mechanism 3 is configured to heat the air in the drying chamber 1 by circulating a heating medium (steam) in the heating pipe 31 piped in the drying chamber 1, and the circulation and flow rate of the heating medium. The heating can be controlled by controlling the temperature and the like. The air supply mechanism 4 and the exhaust mechanism 5 are mainly composed of ducts 41 and 51 communicating with the inside and outside of the drying chamber 1 and a fan (not shown) that generates an air flow in the duct, respectively. The intake and exhaust of the drying chamber 1 can be controlled by controlling the rotation of the fan and the opening and closing of the dampers 42 and 52 provided in the duct.

Then, by appropriately controlling the vaporization by the vaporization mechanism 2, the heating by the heating mechanism 3, the air supply by the air supply mechanism 4, and the exhaust by the exhaust mechanism 5, the temperature and humidity in the drying chamber 1 can be set as desired. The temperature and humidity can be controlled.
The drying apparatus may include a temperature measuring means 6 that can measure the temperature inside the wood during drying and a moisture content measuring means 7 that can measure the moisture content inside the wood during drying. Further, the temperature measuring means 6 and the moisture content measuring means 7 may each be capable of measuring the temperature or moisture content inside the wood at two or more parts having different depths from the wood surface. As the temperature measuring means and the moisture content measuring means, for example, those described in Patent Document 1 can be used.
In addition, the drying device fixes a pair of displacement gauge fixing jigs to two adjacent side surfaces of the wood (corner) 10 and a displacement meter fixed between the pair of displacement gauge fixing jigs is drying. You may provide the displacement measurement means which measures the displacement which arises in a square member. As an example of such displacement measuring means, for example, the one described in Patent Document 3 can be used.

  The drying apparatus shown in FIG. 1 includes a control calculation unit 8 electrically connected to a temperature and hygrometer (not shown) installed in the drying chamber 1. The control calculation unit 8 is mainly composed of a personal computer. The calculation unit 8 is also electrically connected with a temperature measurement unit 6, a moisture content measurement unit 7, a displacement measurement unit (not shown), and the like. The temperature, the moisture content, and the amount of displacement generated inside the wood are calculated and output on the display means 9 and / or the printer 11 ′ continuously or at predetermined intervals. The control calculation unit 8 is adapted to change the temperature and humidity in the drying chamber 1 over time in accordance with a predetermined control schedule input from the input means 12 ′, and appropriately adjusts the schedule during drying. It is also possible to make changes.

In the method for drying wood according to the present invention, the mouth end surface of the wood to be dried (wood to be dried) 10 is partially covered with a shielding material, and in this state, the wood is artificially dried.
Artificial drying is drying performed under the control of temperature or temperature and humidity in a space where at least temperature, preferably both temperature and humidity, can be controlled, as in the drying chamber 1 of the drying apparatus shown in FIG. Or vacuum drying. Artificial drying preferably has a high temperature drying step (dry bulb) at a temperature above 100 ° C. and 140 ° C. or less, and more preferably has a high temperature drying step at a (dry bulb) temperature of 110 to 130 ° C. Artificial drying may be intermediate temperature drying in which wood is dried by heating to a temperature of 100 ° C. or lower (for example, 50 to 100 ° C.), reduced pressure drying with heating or reduced pressure drying without heating, or the like.

  The shield covering the lumber surface of the to-be-dried wood can reduce evaporation of moisture from the lumber surface by partially covering the lumber surface of the wood. Mitigation includes those that slow the rate of water evaporation.

One of the preferable shields is a mouthpiece surface shield that can be attached to the wood mouth part so as to cover the wood mouth face.
The mouthpiece surface shield 11 shown in FIGS. 2 and 3 is an example of such a mouthpiece surface shield.
As shown in FIG. 4, the end face shield 11 can be detachably attached to the end portion 10b of the wood 10, and in the state attached to the end portion 10b, one side of the flat shield portion 12 is The timber 10 is configured to abut against the lip 10a of the wood 10 and partially cover the lip 10a.
The lip portion 10b of the timber 10 is a portion located in the longitudinal direction (axial direction) of the timber 10 and the vicinity of the lip surface 10a (for example, a portion within a distance of 10 cm from the lip surface 10a).

As shown in FIG.2 and FIG.3, the shielding part 12 in the mouthpiece surface shielding tool 11 has a substantially square shape, and has a square-shaped opening K at the center. Four projecting pieces 13, 13, 14, 15 are provided around the shielding portion 12. More specifically, the pair of first projecting pieces 13 and 13 are provided on two opposite sides of the shielding unit 12 so as to rise from the shielding unit 12, and the two second projecting pieces 14 and 15 are provided. The other two sides of the shield 12 facing each other are provided so as to rise from the shield 12.
As shown in FIG. 3, the pair of first projecting pieces 13, 13 has portions 13 a, 13 a where the distance W between them is the smallest in the vicinity of the center in the projecting direction (direction perpendicular to the shielding unit 12). And the distance W1 between the two at that portion is smaller than the distance W4 (see FIG. 4) between the two parallel side surfaces 10c, 10c of the wood 10 to which the end face shield 11 is attached. On the other hand, the distance W3 between both ends of the first projecting pieces 13 and 13 in the projecting direction is larger than the distance W4 and is adjacent to the shielding end 12 in the projecting direction of the first projecting pieces 13 and 13. The distance W2 between the two in the part) is equal to or greater than the distance W4.

As shown in FIG. 4, the end cover 11 is fitted into the end 10 b of the wood 10 so that the end 10 b of the end of the wood 10 enters between the pair of first protruding pieces 13 and 13. , And can be easily attached to the end portion 10b. At this time, the end face 10a is brought into contact with the shielding portion 12 to be brought into close contact therewith. Thereby, the evaporation of moisture during drying is reduced in the portion covered by the shielding portion 12 (portion other than the opening K) of the end face 10a.
When attaching the wood end surface shielding tool 11 to the wood end portion 10b, the space between the pair of first projecting pieces 13 and 13 is expanded. The first projecting pieces 13, 13 press the wood 10 from both sides by the elastic restoring force to return to the original state. Therefore, even if the wood 10 contracts due to drying and the distance W4 is somewhat reduced, the first projecting pieces 13, 13 are attached. The state is kept stable.
In the wooden face shield 11, the pair of first projecting pieces 13 and 13 are fixing means for fixing the wooden face shield to the wooden mouth of the wood.

On the other hand, after drying, it is possible to easily remove the end face shield 11 from the wood 10 simply by pulling the end face shield 11. It is preferable that the end cover 11 has heat resistance and can be used repeatedly. Moreover, it is preferable that the end face shield 11 is formed by bending a single metal plate, but is formed by joining another metal plate to the shielding portion 12 made of a single metal plate. It may be a thing.
The metal plate is preferably made of stainless steel that can be used any number of times and is inexpensive and hardly corrodes under high temperature and high humidity, but is not limited thereto.
Further, the end cover 11 may be made of a material other than metal, for example, a resin having a relatively high heat resistance temperature (for example, phenol resin or epoxy resin), ceramic, or the like.

For the purpose of preventing overdrying, the size of the shielding part 12 is preferably equal to or larger than the area of the end face 10a and can cover the entire end face 10a. For example, when obtaining a 90 mm × 90 mm dry square, it is preferable to have a size of 90 mm × 90 mm or more, and when obtaining a dry square of 105 mm × 105 m, it may have a size of 105 mm × 105 mm or more. preferable.
The thickness of the metal plate in the case of forming the mouthpiece surface shield 11 with a metal plate is preferably such that the metal plate has a thickness that allows close contact without causing shrinkage of the wood or deformation due to steam from the wood, for example 0.5 mm or more. Preferably there is.

The second projecting pieces 14 and 15 of the end face shield 11 are provided from the viewpoint of preventing falling off from the end portion 10b of the end face shield 11, and from the viewpoint of more effectively reducing the escape of moisture from the end face. ing.
The second projecting pieces 14 and 15 have a projecting length L14 from the shielding part 12 (the projecting amount measured in the direction perpendicular to the shielding part 12, see FIG. 3), and the projecting length of the first projecting pieces 13 and 13 is the same. It is shorter than L13 (see FIG. 3). This can prevent interference between the second projecting pieces 14 and 15 and the pier when the pier is interposed and the timber is stacked in multiple stages and simultaneously dried.
The projecting length L13 of the first projecting pieces 13, 13 is preferably 20 to 80 mm, and more preferably 30 to 50 mm, for example.
The protruding length L15 of the second protruding pieces 14, 15 is preferably 2 to 20 mm, for example, and more preferably 3 to 10 mm.

5A and 6B is another example of a preferable front end shield.
As shown in FIG. 5, the end face shield 11 </ b> A has a plate-like shielding portion 12 having a square opening K at the center, and protrudes from one side of the shielding portion 12 and is inserted into the end portion 10 a of wood. Needle 16. As shown in FIG. 5, the end face shield 11A has a through hole 12a for inserting a needle around the opening K in the shielding part 12, and a head and a needle are inserted into the through hole 12a. The needle 16 protrudes from one side of the shielding part 12 by inserting the needle 16 of the metal fixture 16A. The head of the fixture 16A has a size larger than the opening of the through hole 12a, and can also suppress evaporation of moisture through the through hole 12a.
As shown in FIG. 6, the end face shield 11A has the shielding portion 12 in contact with the end face 10a of the wood 10, and in this state, the needle 16 of the fixture 16A is inserted into the through hole 12a and pushed in. It can be fixed to the end face 10a. In the end face shield 11A, the fixing tool 16A is a fixing means for fixing the end face shield 11A in a state where the shielding portion 12 is in contact with the end portion 10a of the wood.

  7 is a still another example of a preferable mouthpiece surface shielding tool. In the wooden end surface shielding tool 11B, a metal needle 16 is fixed to the shielding part 12 made of a metal plate by appropriate means such as welding.

  As shown in FIG. 5 to FIG. 7, the shielding part 12 in the front end shields 11 </ b> A and 11 </ b> B has a substantially square plate shape. Further, the opening K has a substantially square shape. The preferable size, thickness, material, and the like of the shielding portion 12 in the end face shields 11A and 11B are the same as those of the end face shield 11 described above. The front end shield 11A can press the head of the fixture 16A by hand, and the front end shield 11B can press the shield 12 by hand to bring the shield 12 into contact with the front end 10a. Although it is preferable, the shielding part 12 may be brought into contact with the end face 10a by hitting the fixture 16A or the shielding part 12 with a mallet or the like.

The needle 16 preferably has a diameter of 0.3 to 3.0 mm, particularly 0.5 to 1.5 mm, at its root (a portion adjacent to the surface of the shielding portion 12 on the side of the wood mouth 10a), and its length. Is preferably 1.0 to 10.0 mm, particularly preferably 2.0 to 5.0 mm.
Further, in the cutout surface shielding tool 11A shown in FIG. 5, the through-hole 12a is provided in the vicinity of the center of each of the four sides of the square shaped shielding part 12, and in the cutout surface shielding tool 11B shown in FIG. The needles 16 are provided in the vicinity of the four corners of the shielding part 12, but the positions and the number of the through holes 12 a and the needles 16 can be changed as appropriate.

Usually, when natural drying is performed, the drying conditions may be stricter than artificial drying, and damage tends to occur more than expected. For this reason, in the material, dry cracks are first generated on the surface of the material and the end of the end of the wood, and it is often extended to develop surface cracks and cracks of the material.
On the other hand, in the case of artificial drying, since the temperature, temperature and humidity can be set to arbitrary conditions, the occurrence of material surface cracks and internal cracks is reduced compared to natural drying. Therefore, usually, drying is started in a state of a solid material.
However, even if it is artificial drying, when high-temperature drying is used, the material often has many surface cracks and internal cracks. When cracks occur as a result of observing the cracking condition of the desiccant, in most cases, both cracks start from the pier, a) the case where the cracks disappear, and b) the cracks are large. It has been found that there are cases where the crack extends to the center in the longitudinal direction of the material.
As a property of wood, it is known that the longitudinal direction (axial direction) of wood has the highest moisture conductivity. In the case of artificial drying, since the drying temperature is higher than that of natural drying, the material is dried first from both ends of the material, and gradually dried toward the center. Actually, when examining the moisture content distribution in the longitudinal direction (axial direction) of the artificial desiccant, the moisture content is low at the ends of both ends, and the moisture content increases toward the center of the material. From this, the shrinkage of the material is also expected to start from both ends, and when the difference in shrinkage with the material on the center side becomes large, it is estimated that cracks occur on the material surface and inside.
For this reason, as a method for reducing the moisture content gradient in the length direction of the material, the moisture content gradient in the length direction (axial direction) is obtained by partially shielding both ends of the material, which results in rapid drying. We decided to reduce the dimensional change inclination.

In addition, the internal cracks that have occurred may occur in the radial direction from the pith (core) in the early stage of drying, or in the case of a) between the pith and the surface layer in the middle of the dry stage. B) Most of the cracks that occur after the mid-drying period occur on the line connecting the pith and the four corners of the column in the case of column material, and when improper drying is performed, the internal cracks vary widely from near the corner to near the pith. Occur.
In addition, as a result of observing the column material in the initial stage of the internal crack, the present inventor found that the internal crack in (a) first occurs on the inner side of the place where the outermost ring is closest to the column side (annual ring region). In addition, it was found that a large amount was generated on the side of the core part near the transition material existing on the line connecting the pith and the four corners of the column, and further on the same line, at the boundary between the core and the sapwood.
Once a small crack is generated, it is expected that the crack will progress to a large crack depending on the drying conditions. The method for suppressing the internal crack in a) is to prevent the generation of a small crack.

  As a result of studying various aspects of partially shielding the end of the mouth, the present inventor has found that the portion where the internal crack of (a) occurs at the initial stage, that is, in the case of a column material, a band connecting the pith and the four corners of the column (practical It was found that the internal cracks can be greatly suppressed by intentionally shielding the same-annular ring part other than the band where cracks are expected to occur without intentionally shielding the zone connecting the pillar center to the four corners of the pillar. .

The present invention is to dry the timber by partially shielding the mouth end of the timber in such a manner.
In the first invention, as shown in FIG. 8, the end face 10a is divided into four areas A to D by two center lines L1 and L2 connecting the midpoints M of opposite sides, and each of the areas is divided. , When the outermost peripheral annual rings Na to Nd that do not reach any of the two adjacent sides are viewed, the inner vicinity Pa of the portion closest to the sides 101 to 104 of the top end of the outermost peripheral annual rings Na to Nd While covering Pd with a shielding object, the inner periphery Ta-Td of the location where the diagonal lines L3, L4 of the end of the outermost annual rings Na-Nd intersect with each other are not covered with the shielding object, and artificial drying of the wood is performed.

  Referring to the upper left region A in FIG. 8 as an example, the outermost peripheral annual ring Na for the region A is an annual ring that does not reach any of the two adjacent sides 101 and 104, and is the outermost in the diametrical direction. It is the annual ring Na located. In addition, with respect to the outermost peripheral annual ring Na, the locations closest to the sides of the mouth end surface are near the midpoint of the side 101 and near the midpoint of the side 104, and the inside of the location is a portion indicated by Pa in FIG. is there. When the position of the portion closest to the side 101 in the outermost peripheral annual ring Na in the region A and the outermost peripheral annual ring Nb in the region B is shifted in the diameter direction of the wood as in the case of the end face shown in FIG. It is necessary to cover both the inner vicinity Pa of the outer peripheral annual ring Na and the inner vicinity Pb of the outermost peripheral annual ring Nb.

Moreover, about the area | region A, the inner side vicinity of the location where the outermost periphery annual ring Na and the diagonal L4 of the end face 10a cross | intersect is a part shown by Ta in FIG. In the outermost peripheral rings Na to Nd, the shield covering the inner vicinity Pa to Pd of the portion closest to the sides 101 to 104 of the mouth end is the same annual ring as the annual ring not covered by the shield in the regions Ta to Td. It is preferable to coat.
In FIG. 8, as Pa to Pd, the length of the short axis is 1/8 of the length of one side of the mouth end surface 10a (same as the length of the center lines L1 and L2). An elliptical region whose length is about 1.5 to 2 times the length of the minor axis is shown as a region divided into two with the minor axis as a boundary. A circular region having a length of 1/8 of the length of one side of the end face 10a (same as the length of the center lines L1 and L2) is shown.

  In the first invention, when there is a transition material inside the outermost peripheral annual ring, the shielding covering the inner side of the portion closest to the edge of the end face of the outermost peripheral annual ring reaches the inner area of the core part of the wood It is preferable that the vicinity of the inside of the location where the diagonal lines in the outermost peripheral annual ring intersect do not cover the range up to the inner area of the core member.

  Inside portions Ta to Td near the points where the diagonal lines L3 and L4 intersect with the outermost peripheral annual rings are portions that are not shielded by a shielding object, but the non-shielding portion 18 is centered from the corners Ca to Cd. It is preferable to have a belt-like form having a certain width La (see FIG. 11) extending toward the portion Cp.

  In the column end, the length Lc (see FIG. 11) from the center of the column to the corner is 1 in the zone from the corner (corner) to the center, and the inner portion is 0.29 or more from the corner. It is preferable to leave as 18. Although the corner to the central portion Cp may be left as the non-shielding portion 18, the corner portion is preferably the shielding portion 17 in order to relieve the shrinkage stress due to rapid drying of the corner.

Further, the non-shielding portion 18 provided near the inside of the location where the outermost peripheral annual ring and the diagonal line L3 (or L4) of the butt face intersect from the center point (intersection of the center lines L1 and L2) Cp of the butt face. Preferably includes a point on the diagonal L3 (or L4) that is equal to the distance from the center point Cp to the midpoint M (half the length of one side). Further, the non-shielding portion 18 provided near the inside of the location where the outermost peripheral annual ring and the diagonal line L3 (or L4) of the end face intersect is a length Ls (see FIG. 11) located on the diagonal line L3 (or L4). ) Is preferably 12.5 to 50% of the length of the diagonal L3 (or L4), more preferably 15 to 45%, still more preferably 17.5 to 35%.
The description of the non-shielding portion 18 is the same for the non-shielding portion formed in the second invention in order to “not cover one or a plurality of annual rings Na ′ to Nd ′ on the diagonal lines L3 and L4 of the end face”. I can say that.

  Moreover, when many sapwood parts exist in the outer periphery of the pillar material, it may be a non-shielding part from the portion where the core material part appears toward the center. Moreover, it is preferable that the non-shielding part toward the center part from the corner is continuous. If there is an intermittent non-shielding part in the radial band from the corner to the center part, there is a greater risk of cracking in the part shielded in the late drying stage.

  In addition, on the columnar end, when the length Lb (see FIG. 11) of the straight line connecting the midpoints M, M of two adjacent sides is 1, the width of the non-shielding portion with the center line as the center from the corner La (see FIG. 11) is preferably 0.1 to 0.75, more preferably 0.2 to 0.65 (for example, 16 to 52 mm in the case of a prismatic material having a side of 115 mm). If the width La of the non-shielding portion is too large, the width range that shrinks early increases, the shrinkage stress increases, and the risk of cracking increases. Moreover, when the width | variety La of a non-shielding part is small, the danger which will remove | deviate from the site | part which cracks arises.

In the second aspect of the invention, as shown in FIG. 9, one or a plurality of annual rings covered with the shield while covering the mouth end surface 10a near the middle point M of each side of the mouth end face with the shield. Artificial drying of the wood is performed in a state where Na ′ to Nd ′ are not covered on the diagonal lines L3 and L4 of the end face.
The shielding portion 17 that covers the vicinity Pm of the middle point M of each side has a length Lm (see FIG. 11) measured along the center line L2 or L1 passing through the middle point M for each middle point M. It is preferably 10 to 50% of the length L of one side (same as the length of the center lines L1 and L2), more preferably 15 to 45%, still more preferably 18 to 40%. The description about the shielding portion 17 is also the width measured along the L1 and L2 of the shielding portion 17 for covering the vicinity of the inside of the portion closest to the edge of the end face of the outermost ring in the first invention. The same can be said. In FIG. 9, a circular region having a diameter of ¼ of the length of one side of the mouth end surface 10a (same as the length of the center lines L1 and L2) centered on the midpoint M is shown as Pm. It is shown.

  In the third invention, as shown in FIG. 10, when the butt face 10a is divided into nine square areas R1 to R9 by dividing each side into three equal corner areas located at the four corners of the butt face. The ratio of the area covered with the shielding in R1R3, R7, R9 is made smaller than the ratio of the area covered with the shielding in the outer peripheral central regions R2, R4, R6, R8 located between two adjacent corner areas. Then, artificially dry the wood. The outer peripheral central region located between two adjacent corner regions is the outer peripheral central region R2 for the corner regions R1 and R3, the outer peripheral central region R6 for the corner regions R3 and R9, and the angular region R9. , R7 is the outer periphery central region R8, and the corner regions R7, R1 are the outer periphery central region R4.

  In the corner region, the ratio of the area of the shielding part (shielding part 17) to the area of each region is preferably 5 to 100%, more preferably 7 to 75%, and still more preferably 8 to 60%. is there. On the other hand, it is preferable that the ratio of the area of the shielding part (shielding part 17) to the area of each area is 30% or more on the assumption that the outer peripheral central part area has a larger ratio of the shielding part than the corner area. More preferably, it is 40% or more, More preferably, it is 50% or more.

FIG. 11 is a diagram showing a preferred arrangement of shielding objects for realizing the shielding of the first to third inventions. In FIG. 11, the shielding part is shown as a black paint part.
FIG. 11A shows an embodiment in which the periphery of the mouth end surface is shielded in a square shape, and FIGS. 11B and 11C show a cross shape with a non-shielding portion provided at the center of the mouth end surface. Fig. 11 (d) shows an embodiment in which the mouth end surface is shielded in a cross shape, and Fig. 11 (e) shows an X-shaped non-shielding portion reaching the corner on the mouth end surface. FIG. 11 (f) is an embodiment in which a non-shielding portion having an X mark that does not reach the corner portion is provided on the end of the mouth and the other portions are shielded.

In the embodiment shown in FIG. 11 (a), the area of the non-shielding portion at the center is 30 to 50% of the area of the end face, regardless of the specific arrangement of the tree rings to be dried, It is preferable from a viewpoint that the ratio of the timber which can shield a front end in the aspect of the 1st-3rd invention increases, More preferably, it is 35-45%. Further, in the embodiment shown in FIGS. 11B to 11D, the width Ld of the shielding portion covering the vicinity of the midpoint M of each side is 25 to 80% of the length L of the side, particularly 35 to 35%. 70% is preferable.
Moreover, it is also preferable to make the area ratio of the non-shielding part of the front end of the wood larger than the area ratio of the non-shielding part of the end face of the wood.

  While partially covering the mouth end surface 10a of the wood 10 in the above-described manner, by making the portion that may develop into an internal crack as the non-shielding portion 18, the shrinkage stress of the portion generated during the drying process is reduced. In addition, it is possible to effectively prevent internal cracks in the initial stage that occur in the vicinity of the mouth end surface. Thereby, it can suppress effectively that an internal crack arises in this wood 10 during drying. The drying method may be either medium-temperature drying or high-temperature drying, but high-temperature drying is preferred because it is considered that shrinkage stress due to softening of the wood is reduced during high-temperature treatment. The larger the non-shielding portion of the mouth end, the more the drying proceeds at the non-shielding portion. Therefore, there is an advantage that the drying time is shortened as compared with the case where the entire face of the mouth end is shielded.

Other preferable examples of the shield in the present invention include a wood surface cracking agent, a sealant or a wood surface coating agent which is a paint, or a silicone resin.
The knot cracking agent is conventionally used to prevent dry cracking in natural drying, but in artificial drying in which the temperature, temperature and humidity can be controlled artificially, the knot cracking agent is used. It never happened. As the crack inhibitor, those conventionally used for natural drying and the like can be used.
The wood surface coating agent is usually a liquid material, and a general coating method using a brush, a spray or the like can be used as an application method. Types of surface coating agents include oil-based paints commonly referred to as paint, cellulose-based, alkyd, urethane, solvent-based typified by fluorine-based, acrylic emulsion, water-based typified by acrylic-urethane-based, lacquer, Although cashew resin etc. are mentioned, it is not limited to this. The coating weight is preferably 50 to 500 g / m ^2, and more preferably 100 to 300 g / m ^2.

As the silicone resin, a silicone sealant usually referred to as a silicone sealant is preferable. Silicone-based sealants are suitable because they can follow the deformation of wood during drying, and water resistance, water repellency, adhesion, heat resistance, cold resistance, weather resistance, and workability are also stable regardless of the season. Examples of the silicone sealant include a general silicone sealant and a silicone coating material. The silicone resin may be one-component type, two-component type, or three-component type, and the curing method may be any of oxime type, alcohol type, acetone type, acetic acid type, and aminoxy type, and is limited to these. It is not what is done.
Coating amount of the silicone resin is preferably from 200 to 800 g / m ^2, and more preferably 300 to 600 g / m ^2.

The wood drying method of the present invention (first to third inventions) can be carried out in consideration of the shape of a specific annual ring of each wood, and by providing a shielding portion in a mode suitable for each wood. Such an embodiment is performed, for example, using one or a small number of sample materials, and is performed to determine the formation mode of the shielding portion used in the later drying having a larger scale.
Moreover, the drying method of the wood of this invention (1st-3rd invention) is uniformly the same aspect (for example, figure) with respect to several pieces (for example, 10-200 pieces) of wood simultaneously drying on the same conditions. 11), a shield can be provided. In this case, there is a possibility that wood that does not satisfy the conditions of the first to third inventions is included in the plurality of woods due to individual differences in the specific shapes of the annual rings of the individual woods. However, the effect of increasing the proportion of wood whose internal cracks are prevented (reduced) is obtained. It is also possible to unify the form of formation of the shielding objects at the front end and the end end of the wood.

Further, the shielding object (the end face shield, etc.) in the first to third aspects of the present invention is a square end face and is centered on the intersection Cp between the center lines L1 and L2 connecting the midpoints M of the sides. Assuming a virtual standard butt face having a large number of concentric circular rings at 3 mm intervals, a shielding part and a non-shielding part can be formed in a manner satisfying the first to third inventions. It is preferable.
The first aspect of the shielding mode when artificially drying the both ends of the cored corner timber by partially shielding with a shielding object is as follows. When it is an aspect that satisfies the conditions defined in the third invention, artificial drying in that state corresponds to the implementation of the first to third inventions. In this case, when actual wood is dried, there is a possibility that wood that does not satisfy the conditions of the first to third inventions is included due to individual differences of the wood, etc., but the first to third inventions are included. The effect of increasing the proportion of wood that satisfies the above conditions and whose internal cracks are prevented (reduced) can be obtained.
Moreover, when the shield in the 1st-3rd invention and the end face shield of the 4th invention assume the timber which has the said virtual standard end face, each constituent requirement of the 1st-4th invention and the above-mentioned It is preferable to satisfy preferable conditions.

As mentioned above, although preferred embodiment of this invention was described, each invention is not restrict | limited to said embodiment, It can change suitably.
For example, the shape of the shielding part 12 of the end face shields 11 and 11A may be a rectangular shape or a circular shape instead of a square shape. In the embodiment shown in FIG. 11 (b), the shape of the non-shielding portion provided at the center of the mouthpiece surface may be a circle, a triangle, a pentagon, or the like instead of a square.
In addition, in the above-described cutout surface shielding tool 11, a total of four protruding pieces are provided around the shielding portion 12, but instead, only one protruding piece is provided around the shielding portion 12, Only a pair of 1st protrusion pieces 13 and 13 can also be provided. Moreover, the 2nd protrusion pieces 14 and 15 can also be made into a pair of protrusion piece which can press a timber from the both sides similarly to the 1st protrusion pieces 13 and 13. FIG.
It is also possible to provide three protruding pieces and four protruding pieces having the same protruding length. Moreover, it can also be set as the bottomed cylindrical wooden end face shielding tool which the adjacent protrusion pieces connect and has the shielding part 12 as a bottom.

Further, as a protrusion that can be inserted into the mouth end surface, a protrusion having a non-circular cross section can be provided instead of the needle 16 having a circular cross section of the end face shield 11A. Further, the end shield member may be attached to the end part by a method other than fitting or inserting a protrusion into the end face.
In addition, the constituent requirements and more preferable requirements of one invention among the first to fourth inventions can be applied to other inventions as appropriate, and the constituent requirements and preferable conditions of two or more inventions are combined. It may be a requirement of other inventions.
In addition, the description omitted in one embodiment and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately applied between the embodiments. Can be substituted for each other. Moreover, the requirements in each embodiment can be interchanged with each other as appropriate.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

[Drying test]
Using a drying apparatus having the configuration shown in FIG. 1, a cored pillar material immediately after sawing made from Tochigi cedar as a material to be dried (a cored square member, without splitting back, a cross-sectional dimension of 11.5 cm × 11.5 cm, a length of 300 cm) No. of regular square materials) (water content before drying 40 to 120%) was dried four times according to the following drying schedule.
[Drying schedule]
Initial cooking process (96 ° C., 12 hours) → first drying process (dry bulb temperature 120 ° C., wet bulb temperature 90 ° C.) → second drying step (dry bulb temperature 110 ° C., wet bulb temperature 90 ° C.) → third drying Process (dry bulb temperature 100 ° C, wet bulb temperature 80 ° C) → fourth drying step (dry bulb temperature 90 ° C, wet bulb temperature 60 ° C)
The time for each step was changed as appropriate while monitoring the moisture content. FIG. 12 shows a typical example of each process.
Drying was performed with an average moisture content of 15% as a target, and was finished when the moisture content of the column material monitored by the moisture meter became 15% or less. Therefore, the drying time was different for each drying material lot, and was adjusted between 140 and 190 hours.

[Example 1]
The both lip faces of 45 undried pillar members were partially shielded by the lip face shield of the form shown in FIG. The shielding part 12 of the mouthpiece surface shielding tool was made of stainless steel (SUS304), had a thickness of 1.0 mm, a size of the grounding surface (shielding part) of the mouthpiece of 115 mm × 115 mm, and a length of the insertion needle 16 of 4 mm. Five types of end face shields were prepared with different aperture rates of the apertures K of the shield 12. Then, it used for said drying test. Both the opening K and the shielding part 12 were square-shaped, and the opening ratio (%) was obtained by the following formula (1).
Opening ratio (%) = area of opening K / area of mouth end × 100 (1)

[Example 2]
A silicone resin (trade name silicone sealant, Cemedine 800, Cemedine Co., Ltd.) was applied with a spatula to the both lip surfaces of 30 undried pillar members, and the shielding portions of each aspect shown in FIG. 11 were provided. The coating amount was 450 g / m ² . The column material after application was left to air dry for one day for curing, and then subjected to the above drying test.
The formation aspect of the shielding part in Table 2 is as follows.
Cross (diamond-excluded) coating: Forming shape of shielding portion shown in FIG. 11B, Ld is 38 mm, and the central non-shielding portion is a square shape of 38 × 38 mm.
Cross (square removal) coating: Forming shape of the shielding portion shown in FIG. 11C, Ld was 38 mm, and the central non-shielding portion was a square shape of 38 × 38 mm.
Cross-coating: The formation of the shielding part shown in FIG. 11 (d), Ld was 38 mm.
X (entire surface): The formation mode of the shielding part shown in FIG. 11 (e), La was 27 mm.
X (central thick) left: The formation mode of the shielding part shown in FIG. 11 (f), La was 38 mm.
X (Thin center) Remaining: The formation mode of the shielding part shown in FIG. 11 (f), La was 27 mm.

[Comparative Example 1]
In the test lot of Example 1, 5 undried pillar materials that did not shield the both ends were put in the above-described drying test.
[Comparative Example 2]
In the test lot of Example 2, 10 undried pillar materials that did not shield the both ends were put in the above-described drying test.

[Evaluation]
About the core-supporting pillar material (total 85 pieces) dried by the methods of Examples and Comparative Examples, the moisture content and internal cracks were evaluated by the methods shown below, respectively, and samples with a moisture content of 20% or less were extracted. The results are shown in Tables 1 and 2.

[Moisture content]
Moisture content after drying: Two parts 10 cm from both ends of each pillar material after drying were cut to a width of 50 mm to obtain a sample, and the weight W1 of the sample was measured. And a sample piece is JIS Z2201. Wood test method In accordance with the moisture content measurement method, leave the sample at 105 ° C. in a dryer, measure the weight W2 after the sample reaches a constant weight, and calculate the moisture content after drying by the following formula (2). Asked.
Water content after drying (%) = (W1−W2) / W2 × 100 (2)

[Internal crack]
Two cut surfaces at a position 10 cm from both ends of each column material after drying were observed, and the degree of internal cracks observed in each cross-section was determined according to the following evaluation criteria, which were evaluated as internal cracks. Moreover, the thing of the next "none" or "small" was set as the internal crack pass. Two samples of the front end side and the end end side were obtained from the individual column members, and the ratio of the number of passed samples to the total number of samples was determined for samples having a moisture content of 20% or less.

〔Evaluation criteria〕
None: No cracks are observed.
Small: There is a crack having a maximum width of 1 mm or less and a length of 20 mm or less.
Medium: A crack that does not correspond to a small crack, and has a maximum crack surface width of 2 mm or less and a length of 50 mm or less.
Large: There is a crack having a maximum width exceeding 2 mm or a length exceeding 50 mm.

  From the results shown in Tables 1 and 2, it can be seen that according to the method of the present invention, the internal cracks of the material to be dried can be significantly reduced as compared with Comparative Examples 1 and 2 (conventional method). The method for drying wood according to the present invention is particularly effective when drying until the moisture content of the pillar material after drying is 20% or less, particularly 15% or less.

Example 3
Further, the same silicone resin as that in Example 2 is applied with a spatula to the 11 wood ends 10a of the pillars similar to those used in Example 1, and the corner region among the nine regions R1 to R9 shown in FIG. Five column materials (hereinafter referred to as cross-coated column materials) having R1, R3, R7, and R9 as non-shielding portions and the entire remaining region as shielding portions were obtained.
[Comparative Example 3]
The same silicone resin as in Example 2 is applied with a spatula to the 15 columnar surfaces 10a of the column members similar to those used in Example 1, and among the 9 regions R1 to R9 shown in FIG. Is a non-shielding part, five pillars (hereinafter referred to as peripherally coated pillars) with the entire remaining area as a shielding part, among the nine areas R1 to R9 shown in FIG. 10, only the central area R5 is a shielding part, Five pillars (hereinafter referred to as center-coated pillars) having the entire remaining region as a non-shielding portion, and the corner regions R1, R3, R7, and R9 among the nine regions R1 to R9 shown in FIG. Thus, five column materials (hereinafter referred to as four-cornered column materials) having the entire remaining region as non-shielding portions were obtained.

  About each pillar material obtained in Example 3 and Comparative Example 3, after drying in the same manner as in Example 1, the internal cracks were evaluated in the same manner. It was a pass. On the other hand, as for the column material of the peripheral coating, 3 out of 7 bodies passed, 10 out of 10 column coatings of the center coating failed, and 9 out of 9 pillars with four corner coatings. My body was rejected.

10 Wood to be dried (wood)
10a Kiguchi surface 11, 11A, 11B Kiguchi surface shield Na-Nd Outermost ring annual ring Pa-Pd Near the inner side of the outermost ring annual ring closest to the edge of the kerf face Ta-Td Diagonal line of the kerf face in the outermost ring Near the inside of the intersection

Claims (9)

A method for drying wood, wherein the wood is artificially dried in a state where the lumber surface of the wood is partially covered with a shield,
When the top end is divided into four regions by two center lines connecting the midpoints of opposite sides, and the outermost annual rings that do not reach any of the two adjacent sides are seen in each region In addition, the inside near the portion closest to the edge of the top end of the outermost ring is covered with the shielding, while the inside near the portion where the diagonal of the top end of the outermost ring intersects is the shielding. A method of drying wood that does not cover and artificially drys the wood. When there is a transition material inside the outermost peripheral annual ring,
The shield covering the vicinity of the inside of the portion closest to the edge of the end face of the outermost ring is covered with a range reaching the inner region of the core part of the wood, and the diagonal line of the outermost ring is intersected. The method for drying wood according to claim 1, wherein the inner portion of the wood does not cover a range up to the inner region of the core part. A method for drying wood, wherein the wood is artificially dried in a state where the lumber surface of the wood is partially covered with a shield,
While covering the end face of the end of the end of each side of the end of the end with the shield, the one or more annual rings covered by the end of the end are not covered on the diagonal of the end of the end of the wood. A method of drying wood with artificial drying. A method for drying wood, wherein the wood is artificially dried in a state where the lumber surface of the wood is partially covered with a shield,
When the side of the top is divided into nine square regions by dividing each side into three, the ratio of the area covered with the shielding in the corner regions located at the four corners of the top is two adjacent A method for drying wood, wherein the wood is artificially dried so as to be smaller than the ratio of the area covered with the shielding in the outer peripheral central region located between the corner regions.   The wood drying method according to any one of claims 1 to 4, wherein the shield is a mouthpiece surface shielding tool that can be attached to a mouth portion of the wood so as to partially cover the mouth end surface of the wood.   The wood according to claim 5, wherein the wooden surface shielding tool includes a plate-shaped shielding portion having an opening in a central portion, and a needle that protrudes from one surface of the shielding portion and is inserted into the wooden surface of the wood. Drying method.   The method for drying wood according to any one of claims 1 to 4, wherein the shield is a wood surface coating agent that is a crack stopper, a sealant, or a paint.   The method for drying wood according to any one of claims 1 to 4, wherein the shield is a silicone resin. A mouthpiece surface shield used for artificially drying the wood with a portion of the wood mouthpiece covered,
A plate-shaped shielding part having an opening in the center part, and a fixing means for fixing the mouthpiece surface shielding tool in a state in which the shielding part is in contact with the wood mouth part of wood,
A mouthpiece surface shielding tool in which a square opening is formed in the shielding portion, and an area of the opening is 30 to 50% of an area of the mouthpiece surface.

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