JP2005096234A - Method and apparatus for drying wood - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly perform the natural drying of individual woods to be dried after chemical injection treatment corresponding to the characteristics thereof to effectively suppress the development of cracking, warpage, distortion or the like in artificial drying. <P>SOLUTION: A control device 80 is equipped with an input part 84 for inputting characteristics of raw material wood W1 and the time of natural drying treatment, a RAM 83 as a memory part for storing a drying period table 831 on which the number of days of natural drying treatment preset corresponding to the characteristics of raw material wood W1 and the time of natural drying treatment is recorded, a natural drying control part 811 for comparing and collating the characteristics of raw material wood W1 and the time of natural drying treatment inputted by the input part 84 with the characteristics of raw material wood W1 and the time of natural drying treatment recorded on the drying period table 831 stored by the RAM 83 to read the number of days of natural drying treatment in the drying period table 831 wherein both of them coincide and an output part 85 for outputting the number of days of natural drying treatment read by the natural drying control part 811 on the basis of the command signal of the natural drying control part 811. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wood drying method and apparatus for efficiently obtaining dry wood by subjecting to-be-dried wood immediately after chemical solution injection treatment to natural drying treatment and then performing artificial drying treatment.

  Conventionally, it is well known that it is effective to inject a predetermined chemical into wood to improve the moisture resistance and decay resistance of the wood to ensure dimensional stability and to impart flame retardancy. Many so-called modified woods that have undergone such chemical injection are now on the market.

  By the way, the process of injecting the chemical into the wood is usually performed by immersing the wood in an aqueous solution mixed with the chemical in a reduced pressure environment for a predetermined time. Since the wood immediately after the chemical solution injection obtained in this way contains moisture that has reached a substantially saturated point, it cannot be shipped as a product as it is.

  Therefore, the wood after the chemical solution injection process is subjected to a drying treatment. However, if the wood immediately after the chemical solution injection is immediately subjected to artificial drying, the energy consumption for drying becomes enormous and the energy cost increases. It will be. In order to avoid this, it is general that the wood after the chemical injection process is once subjected to natural drying (sun drying). In natural drying, drying proceeds relatively rapidly until the moisture content of the wood is reduced to some extent, but when the moisture content is less than about 50%, the drying rate is drastically reduced and 15% to 25 which can be shipped as a dried product. If the moisture content is reduced to%, it takes a very long time (usually one month to several months), resulting in a disadvantage that the drying efficiency is extremely lowered.

  In order to eliminate such inconvenience, after the wood subjected to natural drying has reached a certain dry state (water content around 50%), the wood is loaded into a drying furnace and heated forcibly to dry. In general, it is subjected to so-called artificial drying. By doing so, it is possible to significantly reduce the drying time of the wood after the chemical injection process, and for example, it is possible to put wood used as a structural material for construction on a commercial base.

Note that the drying of wood is described in detail in, for example, Non-Patent Document 1, and the data on page 73 et seq. Regarding the point that it takes a long time to reduce the moisture content to about 20% particularly in natural drying. However, there is no description of the combination of natural drying for wood after chemical injection and artificial drying performed subsequently. The combination of natural drying and artificial drying is described in the section “D drying” on page 451 of Non-Patent Document 2, but there is no description about the drying treatment of wood after chemical treatment.
Actual drying of wood (author: Shigeru Nishio, publisher: Nikkan Wood Newspaper Co., effective date: September 30, 1983) Revised basic wood engineering (author: Hikoichi Sugihara, publisher: Bunkyo Publishing Co., Ltd., effective date: April 20, 1983)

  By the way, the moisture content of wood immediately after chemical treatment ((weight of water in wood / true weight of wood) × 100 (%)) usually exceeds 100% and there is more water than wood. In general, the drying proceeds relatively quickly until the moisture content reaches about 60% in natural drying, and it can be easily predicted at what point the moisture content will be. It is difficult to predict the change over time in the moisture content below that because it varies greatly depending on the weather and the wood structure of each tree species.

  On the other hand, when the moisture content of the wood is dried to near the fiber saturation point (the moisture content in the state where only free water is present and free water is present, depending on the tree species, it is approximately 28% to 30%). In addition, “warp” that warps in an arc shape, “crack” that breaks along the grain, and “twist” that is caused by uneven warping are likely to occur. These “warping”, “cracking” and “twisting” (hereinafter collectively referred to as “damage”) correlate with the drying rate of the wood, and the damage to the wood becomes more significant as the drying rate increases. Are known.

  Therefore, in natural drying, when the moisture content of the wood is finished before the fiber saturation point and the drying is switched to artificial drying with a high drying speed, the damage of the wood becomes significant and the commercial value of the dried wood is impaired. . Therefore, natural drying needs to be continued until the moisture content falls below the fiber saturation point, but if natural drying is continued until the moisture saturation point is significantly exceeded and the moisture content is further reduced, productivity will decrease. become.

  However, in the past, the start time of artificial drying was often affected by the shipment schedule of dry wood, and in natural drying, wood that did not reach the end of drying was turned to artificial drying, or conversely, it was too dry In fact, only a rough management of natural drying was done, such as artificial drying of wood. Therefore, the obtained dry wood has many variations in quality, resulting in a problem that a stable price cannot be maintained.

  The present invention has been made in view of such a situation, and allows natural drying to be appropriately performed according to the characteristics of individual to-be-dried wood after the chemical solution injection treatment. An object of the present invention is to provide a wood drying method and apparatus that can suppress the occurrence of cracking, warping, and twisting as much as possible, thereby improving the commercial value of dry wood.

  The invention according to claim 1 (wood drying method) is a method of performing natural drying treatment on a chemical solution injection wood obtained by subjecting raw material wood to a chemical solution injection treatment to obtain a natural dry wood. In the wood drying method for obtaining dry wood by performing a drying treatment, the number of days of natural drying treatment in which the moisture content of the air-dried wood is set to a predetermined value according to the characteristics of the raw wood is set in advance. It is characterized in that dry wood is obtained by subjecting the air-dried wood after the passage of days to artificial drying.

  The invention according to claim 2 (wood drying method) is characterized in that, in the invention according to claim 1, the artificial drying treatment is continued until the moisture content of the dried wood reaches a predetermined value set in advance. Is.

  The invention according to claim 3 (wood drying device) obtained a natural dry treatment based on the control of the control device on the chemical injection wood obtained by performing the chemical injection treatment on the raw material wood to obtain a natural dry wood. Thereafter, in the wood drying apparatus for obtaining dry wood by subjecting the air-dried wood to an artificial drying process, the control device includes an input unit for inputting characteristics of the raw material wood and a time for performing the natural drying process, A storage unit for storing the number of days of natural drying processing set in advance corresponding to the characteristics and drying time, and the natural drying daily income corresponding to the characteristics of the raw material wood and the drying time input by the input unit from the storage unit A natural drying control unit to be obtained, and an output unit that outputs the natural drying days read by the natural drying control unit based on a command signal of the natural drying control unit. .

  According to a fourth aspect of the present invention (the wood drying apparatus), in the third aspect of the invention, the natural drying control unit reads the natural drying days read from the storage unit on the date of acceptance of the raw material wood input to the input unit. Is added to calculate the natural drying end date, and the output unit is configured to output the natural drying end date.

  According to a fifth aspect of the present invention (the wood drying apparatus) according to the third or fourth aspect of the present invention, a drying furnace for performing an artificial drying process on the raw material wood is provided, and the control apparatus controls the artificial drying. The controller has a control unit, and the artificial drying control unit determines whether or not the moisture content detected by the moisture content sensor that detects the moisture content of the wood being artificially dried has decreased to a predetermined value, An operation stop command signal is output to the drying furnace when the pressure drops to a predetermined value.

  According to the invention described in claim 1 (wood drying method), the number of days of natural drying treatment in which the moisture content of the air-dried wood becomes a predetermined value in accordance with the characteristics of the raw wood into which the chemical solution has been injected is set in advance. Since the air-dried wood after the natural drying treatment has passed, artificial drying is performed, so that the dry days set in advance correspond to the characteristics of the wood (for example, tree species, shape, weight, etc.) By adopting such a number of days that the moisture content of the wood after this number of days has passed, the moisture content is such that the wood does not warp, cracks and twists even when subjected to artificial drying treatment. Even if artificial drying is applied to the dried wood, it is possible to effectively suppress the occurrence of warping, cracking, twisting, etc. in the dry wood as a product.

  Therefore, as in the past, when natural drying days are not strictly set according to the characteristics of the raw material wood, and the dry days determined based on experience and intuition are adopted, artificial drying treatment Some of the dry-timbers that are attached to the water content have a moisture content that tends to cause warping, cracking and twisting, and many of them cause warping and cracking during the artificial drying process where the drying speed is high. However, there is a problem that the quality of the finished dry wood varies and the product value of the dry wood decreases. According to the invention of claim 1, it is possible to suppress the occurrence of such a problem as much as possible. This makes it possible to produce dry wood with improved product value with less warping, cracking and twisting.

  According to the invention described in claim 2 (wood drying method), since the artificial drying process is continued until the moisture content of the dried wood reaches a predetermined value set in advance, the wood is too dry. Therefore, it is possible to reliably prevent the occurrence of inconveniences such as extreme shrinkage and dimensional deviation.

  According to the invention described in claim 3 (wood drying device), the chemical solution-injected wood obtained by subjecting the raw material wood to the chemical solution injection treatment is subjected to natural drying treatment based on the control of the control device, so that After being obtained, artificial drying treatment is applied to dry-timber to obtain dry wood, which eliminates the negative effects of natural drying treatment that relies on conventional experience and intuition, and realizes natural drying by controlling the control means can do.

  Specifically, the control device stores an input unit for inputting the characteristics of the raw material wood and the time when the natural drying process is performed, and a memory for storing the number of days of the natural drying process set in advance according to the characteristics of the raw material wood and the time of drying. A natural drying control unit that compares the characteristics and drying time of the raw material wood input by the input unit with the characteristics and drying time of the raw material wood stored in the storage unit, and reads the natural drying days that match And an output unit that outputs the natural drying days read by the natural drying control unit based on the command signal of the natural drying control unit, so that the characteristics of the raw material wood and the time when the natural drying process is performed are input to the input unit Thus, the natural drying control unit selects and reads the optimum natural drying days according to the characteristics and time of the raw material wood stored in the storage unit based on this input data, and reads this Natural drying days is output by the output unit.

  Therefore, the same effect as that of the invention according to claim 1 can be obtained by subjecting the chemical-injected wood obtained by injecting the chemical into the raw material wood to natural drying treatment for the number of days output by the output unit. Can do.

  According to the invention of claim 4 (wood drying device), the natural drying control unit calculates the natural drying end date by adding the natural drying days read from the storage unit on the date of receiving the raw material wood, and the output unit is Because it is configured to output the natural drying end date, by inputting the acceptance date in addition to the characteristics and time of the raw wood into the input unit, the natural drying in addition to the optimal natural drying days in the output unit The end date of can be output.

  As the output form of the output unit, in addition to screen output to the monitor, printing output on paper is also performed, and the obtained output paper is affixed to the chemical injection wood to be naturally dried. By checking this output paper, it is possible to confirm the artificial drying start date of the wood that is being naturally dried, and to manage the natural drying treatment for chemical-injected wood without leaks. Can be realized.

  According to the invention described in claim 5 (wood drying device), the control device has an artificial drying control unit for controlling artificial drying, and the artificial drying control unit detects the moisture content of the wood during artificial drying. It is configured to determine that the artificial drying is completed in a state where the moisture content detected by the moisture sensor has reached a predetermined value, and to output an operation stop command signal to a drying furnace that performs the artificial drying. Therefore, the artificial drying process is stopped when the moisture content detected by the moisture content sensor reaches a predetermined value set in advance, and this causes extreme shrinkage due to the wood not being dried or being too dry. Thus, it is possible to surely prevent the occurrence of inconveniences that cause dimension deviation.

  FIG. 1 is a process diagram showing an embodiment of a tree drying method according to the present invention. As shown in FIG. 1, the raw material wood W1 is natural in a chemical solution injection step P1 for injecting a chemical solution into the raw material wood W1, a curing step P2 for curing the chemical solution injection wood W2 in which the chemical solution has been injected, and a cured wood W3. The product is commercialized as a dry wood W5 through a natural drying process P3 for performing a drying process and an artificial drying process P4 for performing an artificial drying process on the natural dry wood W4 that has been subjected to natural drying.

  In the present embodiment, as the raw material wood W1, a so-called square or square as a structural material for construction that has been previously sawn or assembled to have a side dimension of 90 mm to 120 mm and a length dimension of approximately 4 m. However, the wood to be subjected to the drying method of the present invention is not limited to these squares and laminated wood, and may be a plate or a log before sawing.

  The said chemical | medical solution injection | pouring process P1 is a process of inject | pouring a predetermined | prescribed chemical | medical solution with respect to the raw material wood W1, and moisture resistance, decay resistance, dimensional stability, a flame retardance, etc. are given to the raw material wood W1 through this chemical | medical solution injection | pouring process P1. To add value. Examples of injectable drugs include oil-based creosote oil, and water-soluble ones such as chromium, copper, arsenic compound drugs, phenols, inorganic fluoride drugs, alkylammonium compound drugs And chromium / copper / zinc compound chemicals, copper / boric acid / azole compound chemicals, and boron / alkylammonium chemicals. Furthermore, examples of emulsifying agents include fatty acid metal salt-based drugs and azole compound-based drugs, but are not limited to these, and various drugs exist. Incidentally, in the present embodiment, a water-soluble or emulsifiable one is employed.

  In this chemical injection step P1, an aqueous solution (ie, chemical solution) of a drug set to a predetermined concentration is filled in a predetermined chemical solution storage tank that can be sealed, and the raw material wood W1 is introduced into this chemical solution storage layer to fill the chemical solution. The method of immersing in is adopted. Then, with the raw material wood W1 immersed in the chemical solution, once the inside of the chemical solution storage tank is decompressed and the air in the wood tissue is extracted, and then the chemical solution storage tank is pressurized, thereby efficiently supplying the chemical solution to the raw material wood. It can be injected into W1. A curing process is performed in the next curing process P2 on the chemical-implanted wood W2 that has been subjected to the chemical injection process for a predetermined time in the drug injection process P1.

  In the curing process P2, the chemical-injected wood W2 obtained in the previous chemical-solution injection process P1 is taken out from the chemical-solution storage tank and left as it is in a curing position with a roof, so that moisture in the chemical solution attached to the surface is removed. This is a process for evaporating and infiltrating the drug in the chemical solution into the wood tissue, and is usually performed by leaving it for several days. In the cured wood W3 obtained through the curing process P2, the moisture content that has exceeded 100% has been reduced to approximately 60%. Cured wood W3 that has undergone the curing process P2 is the target of natural drying treatment.

  In the natural drying step P3, the cured wood W3 obtained in the curing step P2 (in the natural drying step P3, the cured wood W3 is a so-called raw material wood) is subjected to solar air drying treatment, and natural drying is thereby performed. This is a process for obtaining the dry wood W4. In this natural drying process P3, the cured wood W3 is transported to an unsealed sun drying field and stacked in a so-called stacking system that is piled up in a cross-girder shape, so-called heavens while being exposed to direct sunlight in a well-ventilated state. Natural drying process by sun drying is executed.

  In the present invention, the cured wood W3 to be subjected to the natural drying step P3 further takes into account the factors of time (spring, summer, autumn, winter) according to the characteristics of the tree species, shape, weight, etc. Thus, the end date of the natural drying treatment is given by the method described in detail later. The date is given by pasting a drying end date display sheet 853 (FIG. 7), which will be described later, on the surface of the cured wood W3. The date described in the drying end date display sheet 853 is also the first day of the artificial drying process in the artificial drying step P4.

  The artificial drying step P4 is a step of performing an artificial drying process on the air-dried wood W4 that has been subjected to the natural drying process in the natural drying step P3. The air-dried wood W4 is forced by heating in the artificial drying step P4. A typical drying process is performed, and it dries quickly and becomes dry wood W5 as a product. Hereinafter, the drying furnace 10 used in the artificial drying step P4 will be described with reference to FIG.

  FIG. 2 is an explanatory view in cross-sectional view showing an embodiment of the drying furnace 10 used in the artificial drying step P4. As shown in FIG. 2, the drying furnace 10 includes a rectangular parallelepiped drying furnace body 20, a boiler 30 used for adjusting the temperature and humidity in the drying chamber 21 of the drying furnace body 20, and the drying chamber 21. A fan device 40 which is provided on the inner wall surface and stirs by forming an airflow in the air in the drying chamber 21, a ventilation fan 50 which ventilates the air in the drying chamber 21, and a wet and wet bulb which detects the temperature in the drying chamber 21 It comprises a humidity sensor 60 and a dolly 70 on which the dry wood W4 can be placed.

  On one side surface (left side surface in FIG. 2) of the drying furnace body 20, an entrance / exit 22 through which the cart 70 carrying the dry wood W4 passes is opened and can be opened and closed to close the entrance / exit 22. An opening / closing door 23 is provided. Further, on the floor surface in the drying chamber 21, a rail 24 drawn from the outside through the entrance / exit 22 is laid, and the carriage 70 is guided by the rail 24 so as to enter and exit the drying chamber 21. It has become. In addition, a ventilation cylinder 25 communicating with the drying chamber 21 is provided on the top plate of the drying furnace body 20, and the ventilation fan 50 is built in the ventilation cylinder 25.

  The drying furnace body 20 configured in this way is formed by a material in which each of the four wall portions and the top plate are subjected to heat insulation treatment, and thereby the temperature environment in the drying chamber 21 is affected by the outside air temperature. It is designed to be stable.

  The boiler 30 includes a steam outlet pipe 31 for extracting the generated steam S and an exhaust steam receiving pipe for receiving the exhaust steam S1 used for heat exchange with the surrounding air in the drying chamber 21. 32 is provided. A steam heater 33 is interposed between the pipe ends of the steam outlet pipe 31 and the exhaust steam receiving pipe 32, and the steam S from the boiler 30 is supplied to the steam heater 33, whereby the air in the drying chamber 21. Is to be heated. Further, the boiler 30 is provided with a steam introduction pipe 34 for directly introducing the steam S into the drying chamber 21 in order to adjust the humidity in the drying chamber 21.

  The steam outlet pipe 31 is provided with a first control valve 35 for adjusting the flow rate of the steam S supplied to the steam heater 33, and the steam introduction pipe 34 is directly introduced into the drying chamber 21. A second control valve 36 for adjusting the flow rate of the steam S is provided, and the temperature and humidity in the drying chamber 21 can be adjusted by adjusting the flow rate of the steam S by the first and second control valves 35 and 36. ing.

  The fan device 40 includes a fan motor 41 fixed at an appropriate position on the wall surface in the drying chamber 21 and a plurality of fans 42 fixed to a drive shaft of the fan motor 41. The air in the drying chamber 21 flows due to the integral rotation around the drive shaft of the fan 42 by driving the fan motor 41 of the fan device 40, and the temperature and humidity in the drying chamber 21 become uniform due to the mixing effect of air. I am doing so.

  The ventilation fan 50 is for exhausting the air in the drying chamber 21 and replacing it with fresh air. The ventilation motor 51 is mounted on the ventilation cylinder 25 in a vertically placed state, and the drive shaft of the ventilation motor 51. And a plurality of fans 52 fixed to each other. The ventilation motor 51 is provided at a constant pitch in the circumferential direction from the inner peripheral surface of the ventilation cylinder 25 toward the cylinder center while being positioned in the ventilation cylinder 25 so as to be concentric with the cylinder center of the ventilation cylinder 25. Supported by a plurality of support pieces 53. Therefore, the air in the drying chamber 21 sucked by the rotation of the fan 52 around the axial center by driving the ventilation motor 51 is exhausted to the outside through the gap between the support pieces 53.

  The wet and wet bulb humidity sensor 60 detects the dry bulb temperature and the wet bulb temperature in the drying chamber 21, and includes a dry bulb temperature sensor 61 and a wet bulb temperature sensor 62. The dry bulb and wet bulb temperature sensors 61 and 62 have their detection ends positioned at appropriate positions in the drying chamber 21, and thereby can appropriately detect the dry bulb temperature and the wet bulb temperature in the drying chamber 21. ing. Incidentally, in the present embodiment, a so-called Asman ventilation moisture meter which employs a thermocouple as the wet and dry bulb humidity sensor 60 is employed.

  The cart 70 includes a flat cart body 71 and four wheels 72 provided at four corners on the lower surface side of the cart body 71. Such a carriage 70 is guided by the rails 24 when the wheels 72 roll on the rails 24 and travels. On the carriage main body 71, a plurality of air-dried timbers W4 stacked in a plurality of stages in a so-called cross-beam shape are mounted via a predetermined number of piers 73 arranged orthogonal to the air-dried timber W4. . Then, the dolly 70 loaded with the air-dried wood W4 is pushed into the drying chamber 21 through the opened entrance 22 and the air-dried wood W4 is subjected to an artificial drying process with the door 23 being closed. It has become so.

  In the present invention, a control device 80 composed of a microcomputer is provided in the vicinity of the drying furnace 10. Based on the control of the control device 80, process control in the natural drying process P3 and drying in the artificial drying process P4 are performed. Operation control of the furnace 10 is performed.

  FIG. 3 is a block diagram for explaining the outline of the process management control of the natural drying process P3 and the operation management control of the artificial drying process P4 by the control device 80. As shown in this figure, the control device 80 includes a central processing unit (CPU) 81 that is a central processing unit, a read only memory (ROM) 82 that is a read-only external storage device, and a readable / writable external storage device. A random access memory (RAM) 83, an input unit 84 that performs a predetermined input to the CPU 81, and an output unit 85 that outputs a processing result of the CPU 81.

  In the present invention, the CPU 81 is provided with a natural drying control unit 811 that manages the schedule of the natural drying process in the natural drying step P3 and an artificial drying control unit 812 that performs operation control of the drying furnace 10. Yes.

  The ROM 82 stores a program necessary for causing the natural drying control unit 811 and the artificial drying control unit 812 to function. When the control device 80 is started, a predetermined program stored in the ROM 82 is read into the CPU 81. Thereafter, based on this program, the natural drying control unit 811 and the artificial drying control unit 812 perform predetermined control according to a preset procedure.

  The output unit 85 outputs the processing result by the CPU 81 so as to be visible. In the present embodiment, the output unit 85 includes a display 851 that outputs a screen to a predetermined monitor device, and a printer 852 that prints and outputs the paper. Has been.

  Next, the control by the natural drying control unit 811 (managing the natural drying process) will be described. The natural drying control unit 811 sets the number of days for the natural drying process for the cured wood W3 for which the curing process in the curing process P2 has been completed.

  In order to set the number of days, in the present embodiment, various data related to the cured wood W3 are input from the input unit 84. Then, the natural drying control unit 811 sets the natural drying days based on the input data, causes the display 852 of the output unit 85 to output the natural drying days and various data associated therewith, and causes the printer 852 to output the data. It is designed to print out.

  FIG. 4 is an input data list showing one embodiment of data input to the input unit 84. As shown in FIG. 4, in this embodiment, as input data, the acceptance date (year / month / day) when the cured wood W3 is received in the natural drying step P3, the tree species of the cured wood W3 (wood, cedar, firewood, Rice bran (American cocoons), SYP (Southern yellow pine), whitewood, yellowwood, laminated wood, etc. are entered as symbols, and the size of the raw wood W1 (vertical (mm) x horizontal (mm) x length (Mm)), moisture content (%) of cured wood W3, and target moisture content (%) of dry wood W5 as a product to be shipped. These input data are used as factors for setting the natural drying period. In the present embodiment, the number (lines), chemical injection date (year / month / day), curing period (days), outside air temperature (° C.), outside air humidity (%), etc. are also input for reference.

  On the other hand, the RAM (storage unit) 83 stores a dry days table 831. FIG. 5 is a conceptual diagram conceptually showing an embodiment of the dry days table 831. As shown in FIG. 5, the dry days table 831 has four types of time tables: a spring table, a summer table, an autumn table, and a winter table. FIG. 5 shows a spring table and a summer table.

  Each time table is divided according to the target moisture content. In the example shown in FIG. 5, 15%, 20%, 25%, 30%, and 35% or more are adopted as the target moisture content.

  Further, a unit table 832 which is a table of a minimum unit is formed by dividing each target moisture content according to the tree species. In this unit table 832, the moisture content of the cured wood W3 is set as an item in the vertical column, and the size of the cured wood W3 is set as an item in the horizontal column. Depending on the items in the vertical column and the horizontal column, The natural drying days at the set position and the wet and dry temperature difference (difference between the detected temperature of the dry bulb temperature sensor 61 and the detected temperature of the wet bulb temperature sensor 62) used as a control target in the artificial drying step P4 which is the next step It is shown.

  The natural drying days described in the unit table 832 are set as values having a width. For example, in the unit table 832 (the first one of the unit table 832 shown in FIG. 5) of “spring”, “target moisture content 15%” and “tree species A”, the moisture content of the cured wood W3 is α%. The natural drying days of size a are set to 50 to 60 days. This means that when the natural drying treatment of the cured wood W3 is performed in the spring, the target moisture content of the dried wood W5 shipped as a product is 15%, the tree species is A, and the moisture content is α, When the size is a, it indicates that the number of days for the natural drying process may be set within a range of 50 to 60 days. And if it is the number of days within this range, when the natural drying treatment is completed, the moisture content of the air-dried wood W4 becomes 40% or less from the fiber saturation point (28% to 30%, depending on the tree species). Therefore, even if the obtained dry wood W4 is subjected to the artificial drying step P4, damage such as warping, cracking, and twisting can be avoided.

  The drying days table 831 is obtained by compiling past operation results of natural drying processing and artificial drying processing, and results of natural drying tests and artificial drying tests performed on many samples.

  The natural drying control unit 811 discriminates the time from the acceptance date input via the input unit 84 (from March to May in spring, from June to August in summer, and from September to November in autumn). , December to February are determined as winter seasons), and RAM83 with this time period and the input target moisture content of dried wood W5, tree species of cured wood W3, moisture content and size of cured wood W3 as keywords. Is searched, and the corresponding natural drying days are extracted.

  The natural drying days obtained in this way are output to the display 851 of the output unit 85 and printed by the printer 852. FIG. 6 is an output data list showing one embodiment of the output data. The contents of Examples 1 to 3 of this output data list are associated with those of the input data list of FIG.

  As shown in FIG. 6, in the output data list, the input date, the tree type, the moisture content of the cured wood W3, the size and the target moisture content of the dried wood W5 are listed as input items, and the output items are The natural drying period, the natural insertion end date, and the wet and dry temperature difference are listed. For example, according to Example 1, the acceptance date of accepting the cured wood W3 after the curing process P2 to the natural drying process P3 is July 20, 2003, the tree species is Hem / GR / 15, and the cured wood W3 The moisture content is 65% and the size is 110 mm × 110 mm × 4000 mm.

  For such cured wood W3, 50 to 60 days are set as the natural drying period, and the number of days is output as an output item, and the natural drying end obtained by adding this number of days to the acceptance date The date (August 28, 2003 to September 7, 2003) is also output. Therefore, by looking at this output data list, the cured wood W3 of Example 1 accepted on July 20, 2003 is any day between August 28, 2003 and September 7, 2003. It can be seen that the natural drying process is terminated and the process proceeds to the artificial drying step P4.

  In this embodiment, the printer 852 prints out a drying end date display sheet 853 for displaying the natural drying end date as shown in FIG. 7 in addition to the output data list. On the drying end date display sheet 853, only the tree species and the natural drying end date are printed in large letters. As the drying end date display sheet 853, for example, a sheet in which an adhesive layer and release paper are laminated on the back surface is adopted.

  Therefore, the drying end date display sheet 853 is attached to the target cured wood W3 in a state where the release paper is peeled off and the adhesive layer is exposed, so that the drying end date display sheet 853 is visually recognized at the site of natural drying treatment. By doing so, it is possible to know when to transfer the cured wood W3 to the artificial drying process P4, so that dry management without error is realized and the work is proceeded while checking the actual product against the book one by one Compared to the above, the efficiency of field work can be achieved.

  The drying end date display sheet 853 may be attached to each piece of the cured wood W3 or may be attached in units of lots for the drying process. Usually, the drying process of wood is generally performed in lot units in which a plurality of raw woods W1 of the same tree species are grouped together. Therefore, in consideration of workability, a drying end date display sheet 853 in lot units is considered. It is preferable to stick.

  Next, returning to FIG. 3, the artificial drying control unit 812 will be described. The artificial drying control unit 812 controls the temperature and humidity in the drying chamber 21 of the drying furnace 10, and can thereby perform an appropriate artificial drying process on the air-dried wood W <b> 4. And in this embodiment, the feedback control which makes the temperature in the drying chamber 21 follow the change of the preset time-dependent temperature and humidity is performed. A preset temperature change with time is stored in the RAM 83.

  Then, the artificial drying control unit 812 compares the temperature difference between the read current set temperature and the dry bulb temperature detected by the dry bulb temperature sensor 61 while reading out the temporal temperature change stored in the RAM 83 one by one. When the detected temperature is lower than the set temperature, a control signal for increasing the opening degree is output to the first control valve 35, while in the opposite case, a control signal for decreasing the opening degree is output to the first control valve 35. It is designed to output.

  The humidity in the drying chamber 21 is controlled so that the temperature difference (dry humidity temperature difference) between the temperature detected by the dry bulb temperature sensor 61 and the temperature detected by the wet bulb temperature sensor 62 becomes a predetermined value. . Since the wet / dry temperature difference is stored in the unit table 832 (FIG. 5) of the RAM 83, this value is read and used.

  Then, the artificial drying control unit 812 compares the set dry / wet temperature difference read from the unit table 832 with the detected dry / wet temperature difference obtained from each of the dry bulb temperature sensor 61 and the wet bulb temperature sensor 62 for detection. When the wet / dry temperature difference is larger than the set dry / humid temperature difference (that is, when the actual humidity is lower than the set humidity), a control signal for increasing the opening degree is output toward the second control valve 36, while the reverse In this case, a control signal for decreasing the opening degree of the second control valve 36 is output.

  Moreover, in this embodiment, the moisture sensor 11 which detects the moisture content of the drying wood W4 during drying is provided in the appropriate place of the drying furnace main body 20, The detection signal which this moisture sensor 11 detected is the artificial drying control part. 812 is input one by one. As the moisture sensor 11, a resistance type moisture sensor using the fact that the electrical resistance value of wood changes in proportion to the moisture content, and a high frequency type using the fact that the dielectric constant of wood changes depending on the moisture content. A moisture sensor is common, and any of these may be adopted.

  The artificial drying control unit 812 completes drying when the moisture content value detected by the moisture sensor 11 reaches the target moisture content (see the input data list in FIG. 4) input from the input unit 84. And a control signal for closing the valve is output from the artificial drying control unit 812 toward the first and second control valves 35 and 36, and a drive signal for driving the ventilation fan 50 is output toward the ventilation fan 50. It has become so. In the state where supply of steam S from the boiler 30 into the drying chamber 21 is stopped by these driving signals, the heated air in the drying chamber 21 is exhausted to the outside through the ventilation cylinder 25 by driving the ventilation fan 50. At the same time, fresh low-temperature air is introduced into the drying chamber 21 from a predetermined suction port of the drying furnace body 20, whereby the inside of the drying chamber 21 is rapidly cooled to room temperature.

  Note that the fan device 40 is normally driven while the drying process is continued in the drying chamber 21, and when the moisture sensor 11 detects the target moisture content, the artificial drying controller It is stopped by a stop signal output from 812.

  As described above in detail, in the wood drying method according to the present invention, a chemical solution is injected into the raw material wood W1 in the chemical solution injection step P1, and the obtained chemical solution injection wood W2 is subjected to a curing process for a predetermined number of days in the curing step P2. The obtained cured wood W3 is subjected to natural drying treatment for the number of days of natural drying treatment that is preset according to the characteristics of the raw material wood W1 and the moisture content of the air-dried wood W4 is less than a predetermined value. Since the artificial dry wood W4 is artificially dried, the number of days according to the characteristics of the wood (for example, tree species, shape, weight, etc.) is set as the dry days set in advance, and this number of days has passed. The number of days in which the moisture content of the later wood is such that the moisture content is less likely to warp, crack and twist even after artificial drying (ie, the moisture content of the cured wood W3 is below the fiber saturation point). It is obtained by adopting Warping and cracking dry wood W5 as product Ten'inui timber W4 in the subsequent artificial drying step P4, it is possible to make such twisting does not occur.

  Therefore, when the natural drying days are not set strictly according to the characteristics of the raw material wood W1 and the natural drying days determined based on experience and intuition are adopted as in the past, artificial drying is performed. Among the dry-wood timber W4 subjected to the artificial drying process in the process P4, the moisture content does not reach the fiber saturation point, and the moisture content that tends to cause warpage, cracking and twisting remains. There are many cases where warping and cracking occur in the artificial drying process P4 where the drying speed is fast, and this causes inconvenience that the quality of the finished dry wood W5 varies and the product value of the dry wood W5 falls. According to the invention, it is possible to suppress the occurrence of such inconveniences as much as possible, and thereby it is possible to produce a dry wood W5 with improved product value with less warping, cracking, and twisting.

  In addition, the artificial drying process in the artificial drying step P4 is continued until the moisture content of the dry wood W5 reaches a preset target moisture content, and is controlled by the control device 80 so as to stop as soon as it reaches. Therefore, it is possible to surely prevent the occurrence of inconveniences such that the shrinkage of the wood due to excessive drying causes a dimensional error.

  In the present embodiment, the control device 80 sets in advance according to the characteristics of the raw material wood W1 and the time when the natural drying process is performed, and the characteristics of the raw material wood W1 and the time of the natural drying process. RAM 83 as a storage unit for storing a dry days table 831 in which the number of days of natural drying treatment performed is recorded, and characteristics of the raw wood W1 input by the input unit 84 (the species of the raw wood W1 and the water content of the cured wood W3) Rate, the size of the cured wood W3 and the target moisture content of the dried wood W5) and the drying time, and the characteristics and the drying time of the raw material wood W1 recorded in the drying days table 831 stored in the RAM 83, Based on the command signal of the natural drying control unit 811 for reading the natural drying days in the dry days table 831 where both coincide, and the natural drying control unit 811 Natural drying control unit 811 and an output unit 85 for outputting a natural drying days read.

  Therefore, the natural drying control unit 811 is input from the drying days table 831 stored in the RAM 83 based on the input data by inputting the characteristics of the raw material wood W1 and the time when the natural drying process is performed to the input unit 84. The optimum natural drying days corresponding to the characteristics and time of the raw material wood W1 are selected and read, and the read natural drying days are output by the output unit 85.

  In this way, by performing the days management of the natural drying process in the natural drying process P3 by the control device 80, it is possible to save the trouble of selecting the optimum one from the enormous data and to improve the workability of the drying work by that amount. Can do.

  The input unit 84 receives the date of acceptance of the cured wood W3, and the natural drying control unit 811 calculates the natural drying end date by adding the natural drying days read from the RAM 83 to the input date. Since the natural drying end date is output by the output unit 85, the artificial drying start date of the wood during natural drying can be confirmed by visually checking the drying end date display sheet 853 in which the end date is described. It is possible to realize reliable natural drying treatment management without leakage for the chemical-injected wood W2.

  Furthermore, the control device 80 is provided with an artificial drying control unit 812 that controls the artificial drying process in the artificial drying step P4. The artificial drying control unit 812 has a moisture sensor 11 that detects the moisture content of the wood during artificial drying. In order to determine that the artificial drying is completed when the detected moisture content is equal to or lower than a predetermined value set in advance, and to output an operation stop command signal to a predetermined device of the drying furnace 10 that performs the artificial drying. No. 10 is stopped when the moisture content detected by the wet and dry bulb humidity sensor 60 falls below a predetermined value set in advance. It is possible to reliably prevent the occurrence of inconvenience that may occur.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above embodiment, the day management of the natural drying process in the natural drying process P3 is performed using the control device 80, but the present invention controls the day management of the natural drying process. The present invention is not limited to the implementation using the apparatus 80, and a dry days table 831 as illustrated in FIG. 5 is created by filling in a sheet, and the dry days table 831 described on this sheet is visually observed. You may make it search and search for the target natural dry days.

  (2) In the above embodiment, a barcode may be output on the drying end date display sheet 853 shown in FIG. As the bar code, a bar code including various input items and output items in addition to the tree species and the natural drying end date can be adopted. If such a barcode is printed on the drying end date display sheet 853 and this drying end date display sheet 853 is attached to each cured wood W3, the barcode is read by a barcode reader, and a large number of miscellaneous miscellaneous items can be obtained. It is possible to immediately know the history and various information about each of the cured wood W3, which is convenient for performing the drying management in the artificial drying step P4.

  (3) In the above embodiment, the natural dry days set according to the characteristics such as the tree type and size of the cured wood W3 are stored in the RAM 83 as the dry day table 831, and the natural dry control unit 811 uses this RAM 83. However, instead of this, each characteristic of the cured wood W3 is set as an independent variable, and the natural drying day is set as a dependent variable. The correlation equation may be created in advance by analyzing past operation data and experimental data, and this correlation equation may be stored in the RAM 83. Then, if the natural drying control unit 811 calculates the natural drying days based on this correlation equation, it is not necessary to store the huge number of drying days table 831 in the RAM 83, and the RAM 83 can be reduced in capacity accordingly. Can contribute.

  (4) In the above embodiment, as the data items for setting the natural drying days, the acceptance date of the cured wood W3 to the natural drying step P3, the tree species of the cured wood W3, and the moisture content of the cured wood W3 The size of the cured wood W3 and the moisture content of the dry wood W5 are set, but the present invention is not limited to such 5 items as data items for setting the natural dry days, The natural drying days may be set by further adding other items such as the type of chemical solution and the curing period.

It is process drawing which shows one Embodiment of the tree drying method which concerns on this invention. It is explanatory drawing of the cross sectional view which shows one Embodiment of the drying furnace used at an artificial drying process. It is a block diagram for demonstrating the outline | summary of the process management control of the natural drying process by the control apparatus, and the operation management control of an artificial drying process. It is an input data list which shows one Embodiment of the data input into an input part. It is the conceptual diagram which showed notionally one Embodiment of the dry days table. It is an output data table showing one embodiment of output data. It is a figure which shows one Embodiment of the drying completion date display sheet which displays a natural drying completion date.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drying furnace 11 Moisture sensor 20 Drying furnace main body 21 Drying chamber 22 Entrance / exit 23 Open / close door 24 Rail 25 Ventilation cylinder 30 Boiler 31 Steam outlet piping 32 Exhaust steam receiving piping 33 Steam heater 34 Steam introduction piping 35 1st control valve 36 2nd control Valve 40 Fan device 41 Fan motor 42 Fan 50 Ventilation fan 51 Ventilation motor 52 Fan 60 Wet and wet bulb humidity sensor 61 Dry bulb temperature sensor 62 Wet bulb temperature sensor 70 Dolly 71 Dolly main body 72 Wheels 73 Cross 80 Control device 81 CPU
811 Natural drying control unit 812 Artificial drying control unit 82 ROM 83 RAM
84 Input unit 85 Output unit 851 Display 852 Printer P1 Chemical solution injection step P2 Curing step P3 Natural drying step P4 Artificial drying step W1 Raw material wood W2 Chemical solution injection wood W3 Cured wood W4 Tempered wood W5 Dry wood

Claims (5)

In a wood drying method for obtaining a dry wood by subjecting a chemical-injected wood obtained by subjecting a raw material wood to a natural-drying treatment to obtain a natural-drying wood, and then subjecting the natural-drying wood to an artificial drying treatment. ,
The number of days of natural drying treatment in which the moisture content of the air-dried wood becomes a predetermined value according to the characteristics of the raw wood is set in advance, and artificial drying is performed on the air-dried wood after the natural drying treatment days have passed. A method for drying wood, characterized in that dry wood is obtained.   2. The wood drying method according to claim 1, wherein the artificial drying treatment is continued until the moisture content of the dry wood reaches a predetermined value set in advance. After the chemical liquid injection wood obtained by performing the chemical liquid injection process on the raw material wood is subjected to natural drying treatment based on the control of the control device to obtain the air dry wood, the artificial dry treatment is applied to the air dry wood In a wood drying apparatus to obtain dry wood,
The control device has an input unit for inputting the characteristics of the raw material wood and the time when the natural drying treatment is performed,
A storage unit that stores the number of days of natural drying processing set in advance corresponding to the characteristics of the raw material wood and the time of drying;
A natural drying control unit for obtaining from the storage unit the natural drying daily income corresponding to the characteristics and drying time of the raw material wood input by the input unit;
A wood drying apparatus comprising: an output unit that outputs the natural drying days read by the natural drying control unit based on a command signal of the natural drying control unit.   The natural drying control unit calculates the natural drying end date by adding the natural drying days read from the storage unit to the acceptance date of the raw material wood input to the input unit, and the output unit finishes the natural drying 4. The wood drying apparatus according to claim 3, wherein the apparatus is configured to output the date.   A drying furnace for performing artificial drying treatment on raw wood is provided, and the control device has an artificial drying control unit that controls the artificial drying, and the artificial drying control unit detects the moisture content of the wood during artificial drying. Determining whether or not the moisture content detected by the moisture content sensor is reduced to a predetermined value set in advance, and outputting a command signal for stopping operation to the drying furnace when the moisture content is reduced to a predetermined value. The wood drying apparatus according to claim 3 or 4.