JP2634388B2 - Method of drying wood and method of improving permeability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for effectively drying wood by securing liquid and gas permeability by causing breakage or cleavage in a closed wall hole of wood, and a chemical solution permeating wood. It relates to a method for improving the performance.

[0002]

2. Description of the Related Art Wood is a resource that is regenerated year by year, and the stock of planted forests planted after the war is increasing, but low-quality timber and thinned timber are not always fully utilized. The fact is that 60% relies on imports from overseas.
As a result, many issues such as global environmental destruction, national land preservation, and water resources cultivation have been raised, and the development of effective utilization technology is desired.

Conventionally, as a method of drying wood and improving the permeability of a chemical solution, firstly, a chemical solution such as an organic solvent is used as a chemical treatment means to extract a substance deposited in a hole in a wall or to remove the substance. There is an attempt to disassemble the hole.

[0004] Secondly, there is a means for utilizing the permeability from the cut edge by mechanically creating a puncture on the material surface by a needle, laser light or high-pressure injection of liquid or the like. Thirdly, there is an attempt to use steaming treatment, which is well-known as a pretreatment for wood drying, to improve permeability, and is generally known as a physical treatment method such as steaming, steam treatment, low-pressure steam explosion treatment, and heat treatment. I have. In each of these methods, the basic principle is that wood is heated by pressurized steam to soften and destroy the wall holes.

[0005] Referring to the core and sapwood of the cedar wood, in the cross section of the cedar wood 16 shown in FIG. 4, A is the sapwood and B is the core. When the stem of the cedar wood 16 is cut toward the center of the tree, there are shades of color to distinguish between the edge and the center of the wood at the edge of the wood. Material B is dark.

Generally, as shown in FIG. 5, the trunk of a tree is composed of a bark 21, a cambium 22, a sapwood A, a core B, and a pith 23, and water 24 and nutrients 25 sucked from the root are sapwood A.
As a result, photosynthesis occurs by receiving carbon dioxide 26 and light 27 from the outside, and the solution of the photosynthetic substance descends through the phloem of the bark 21 and is distributed to each part and grows. At the time of the young tree, everything is sapwood A. When the tree grows to a certain size, a conical core B is formed at the center of the trunk from the lower part to the upper part, and the sapwood A surrounds the core. It becomes a wrapping shape.

Normally, the diameter of the core material B increases as the diameter of the stem increases, but the ratio of the core material B is low during active periods of hypertrophy.
In old-aged large-diameter trees, the width of the sapwood A is narrow. Sapwood A
In the area of, there is conduction of moisture and storage of nutrients,
In the large-diameter tree, the living cells in the portion of the core B disappear, and the parenchyma cells that have been storing nutrients also stop their activities.

[0008]

Among the above-mentioned various methods known as a conventional method for drying wood or a method for improving chemical liquid permeability, a chemical liquid such as an organic solvent is used as a first chemical treatment means. The method of extracting substances deposited in the wall hole and decomposing the wall hole has disadvantages in operation, such as the expensive organic solvent used and long processing time. There is a problem that it takes extra.

In the second method, a method of mechanically creating a puncture on a material surface with a needle, a laser or a high-pressure liquid jet, the processing time is short, but the processing apparatus is large, and the appearance of the obtained wood is poor. Or the strength is reduced. Further, the physical means using the third steaming treatment is a method of heating wood with pressurized steam to soften and destroy the wall holes. In the wood-related industry, a permanent boiler can be used and a chemical solution after drying is used. Although there is an advantage that the autoclave can be shared by injection etc., there is a possibility that the steaming and steam treatment may cause a change in the color of the wood or a decrease in the strength, and the heat treatment in the low pressure steam explosion treatment is effective at the part close to the tree core However, there is a problem that the apparatus becomes large-scale and cannot be recognized.

[0010] Usually, the factor that governs the drying property and chemical permeability of wood is the wall hole in each cell tissue, and in conifers, the bounded wall hole is the passage. In the sapwood A part, the holes are open, so that the passages are for water or nutrients. However, in the core material B, these holes are closed, so that it is difficult to permeate or permeate a liquid or gas. Generally, this is referred to as closing of the wall hole. However, due to the closing of the wall hole, the above-described problem that the core material B is dried slowly and the injectability of the chemical solution is poor.

In particular, conventionally, conifers are said to be poor in both dryness and impregnation with chemicals, and poor dryness leads to an increase in the weight of wood after logging, resulting in overloading during transportation by vehicle. Spots may occur.

Accordingly, the present invention solves the problems of the conventional methods for drying wood and improving the permeability, and destroys the wall hole closure to improve the drying property and chemical permeability of the wood. It is an object of the present invention to provide a method for drying wood and a method for improving permeability, which are improved, are simple in operation, and have low running costs.

[0013]

According to the present invention, in order to achieve the above object, according to the present invention, wood is fixed in a chamber formed inside a sealed pressure-resistant container, and from one side of the sealed pressure-resistant container. Press the compressed air or compressed gas into the mouth of the lumber and around the lumber .
The present invention provides a method for drying wood, in which free air contained in wood is forcibly dehydrated by sucking compressed air or compressed gas .

According to a second aspect of the present invention, wood is fixed in a chamber formed inside a sealed pressure-resistant container having a heat source on an outer peripheral portion, and the sealed pressure-resistant container is heated by the heating source or steam. At the same time as heating by introduction, pressurized air or compressed gas is injected from one side of the sealed pressure-resistant container into the wood mouth and around the wood, and the other side of the sealed pressure-resistant container
To improve the permeability of wood by sucking compressed air or compressed gas from the wood.

[0015]

According to such a method for drying wood and a method for improving permeability, the closed wall hole is cleaved and broken by the pressure gradient applied to the wood, and free water in the material is forcibly dewatered.
Except for the case where the core part is used as the wood, the drying time until reaching the predetermined moisture content is significantly shortened as compared with the untreated wood, and the core part is subjected to hydrothermal treatment to make the untreated material Compared to this, the drying time until reaching the specified moisture content is shortened, and the reduction in material strength such as bending strength and the change in material color are minimized, and the chemical liquid injection property of treated wood is greatly improved. Is done.

In particular, according to the present invention, not only the drying time of wood is shortened and the drying cost is reduced, but also the chemical solution which is problematic in performing high performance such as chemical treatment and improvement of wood material quality. The effect of homogenizing injectability and speeding up necessary steps such as drying, processing, and impregnation of wood is obtained.

[0017]

EXAMPLES Specific examples of a method for drying wood and a method for improving permeability according to the present invention will be described below. FIG. 1 is a schematic diagram showing a method of pressurizing and suctioning a wood tip used in the present embodiment. In the figure, 1 is an autoclave as a sealed pressure-resistant container, 2 is a heating source arranged on the outer peripheral portion of the autoclave 1, and 3 is an upper side. A cap 4 is a lower cap, and 5 and 5 are O-rings for sealing between the caps 3 and 4 and the autoclave 1, and a chamber 20 formed between the upper cap 3 and the lower cap 4 inside the autoclave 1. A test material 15 is fixed therein with a spring 6 interposed therebetween.

Reference numeral 7 denotes a container filled with compressed air, nitrogen gas or methanol, 8 denotes a pressure valve, 9 denotes a pipe which passes from the pressure valve 8 through the upper cap 3 and is introduced into the chamber 20, and 10 denotes a pressure line. An adjustment valve, 11 is a conduit extending from the inside of the chamber 20 through the lower cap 4 to the pressure adjustment valve 10, and 12 is a gas trap mechanism, 1
3 is a vacuum pump.

[Example 1] First, using a cedar wood (30 years old) from Kochi prefecture immediately after felling as raw wood, this raw wood was R5.
A sapwood cut into a size of 5 × T5.5 × L50 cm was used as a test material 15 and was fixed in a chamber 20 formed inside the autoclave 1 shown in FIG. At this time, the test material 15 is placed on the lower cap 4 on the suction side.
The test material 15 was firmly fixed by providing a cutting tool corresponding to the shape of the test sample 15.

By operating the pressure valve 8, compressed air, nitrogen gas or methanol is injected into the chamber 20 from the container 7 via the pipe 9, so that 5 ( (kgf / cm ² ) for 1 hour, and at the same time, suction from the other end of the wood at the suction pressure of 1 (kg / cm ² ) by driving the vacuum pump 13 via the line 11 and the pressure regulating valve 10. Thus, a treated material was obtained. At this time, nitrogen gas or methanol was collected by the gas trap mechanism 12.

Example 2 In the same manner as in Example 1, a core material obtained by cutting a cedar wood immediately after felling to a size of R5.5.times.T5.5.times.L50 cm as raw wood was used as a test material 15, and the outside of the autoclave 1 was used. While heating the inside of the chamber 20 at 120 ° C. by the heating source 2 provided in the furnace, compressed air, nitrogen gas, or methanol is injected from the one end of the wood and around the wood by 5 (kg).
f / cm ² ) for 4 hours, and at the same time, the suction pressure 1 (kg)
/ Cm ² ) to obtain a treated material.

[Example 3] As the test material 15, a cedar sapwood was used in place of the cedar core material used in Example 2 and treated under the same pressure conditions as in Example 2. Wood was obtained.

[Comparative Example 1] A core material taken out of wood was used as a test material 15 in the same manner as in Example 2, and one core was pressed at a pressure of 15 (kgf / cm ² ) for 1 hour from the edge of the wood and around the wood. The treated material was obtained by assisting suction of 1 (kg / cm ² ) from the other end of the mouth by the driving of the vacuum pump 13.

[Comparative Example 2] A core material obtained by cutting wood as in Example 2 was used as a test material 15, and the inside of the chamber 20 was heated and maintained at 120 ° C by the heating source 2 provided outside the autoclave 1 while autoclaving. Steam was introduced into 1 and a steaming treatment was performed at a vapor pressure of 1.2 (kgf / cm ² ) for 4 hours.

COMPARATIVE EXAMPLE 3 A core material obtained by cutting wood as in Example 2 was used as a test material 15, and the inside of the chamber 20 was heated and maintained at 160 ° C. by a heating source 2 provided outside the autoclave 1. Pressurization for 1 hour, and at the same time, a suction pressure of 1 (kg / cm
^The treated material was obtained by suction in ² ). Table 1 shows each of the above Examples 1 and 2.
Table 1 shows a list of processing conditions and processing methods including Nos. 2 and 3 and Comparative Examples 1, 2, 3 and untreated materials.

[0026]

[Table 1]

Next, the treated material obtained in each of the above Examples and Comparative Examples was placed in a thermo-hygrostat (50 ° C., 65% humidity) and weighed at predetermined time intervals to obtain an approximately equilibrium water content. At that point, the moisture content was determined by the absolute drying method, and the drying property was evaluated.
In addition, in order to examine the material change of each processing material, the bending strength was measured in accordance with JIS-Z-2111, and the material color change was measured for lightness and chroma by a spectral colorimetric difference meter to measure the hunter's color. The equation difference (dE) was determined from the equation difference color.

In order to further compare the permeability of the chemical solution, after drying, a pressure reduction method (pressure reduction 1 kgf / cm ² , 30 minutes, pressure 5 kgf / c)
m ² , 1 hour), and the injection amount was compared.
Table 2 shows the drying time until reaching the predetermined moisture content (50%, 25%). FIGS. 2 and 3 show the drying time for the treated material and the untreated material obtained in each of the examples and comparative examples. The change in the water content (%) is shown.

[0029]

[Table 2]

Further, as shown in Table 3, with respect to the treated material and the untreated material obtained in each of the examples and comparative examples, the bending strength reduction rate (%), the amount of chemical solution injected (kg / m ³ ), and the side infiltration length (mm) And color difference
The result of measuring (dE) is shown.

[0031]

[Table 3]

As shown in Tables 2 and 3, Examples 1 and 2
The wood treated with 2, 3 reaches a predetermined moisture content (50%, 25%) as compared with the untreated wood and the wood of Comparative Examples 1, 2, 3 except for Example 2 using the core material. The drying time up to has been reduced. In the core material part, the effect of shortening the drying time is not seen for both nitrogen gas and methanol. Time to reach almost 3
It was 2 / min. In addition, a decrease in material strength such as bending strength and a change in color of the material were minimized, and the drying property and the injectability of the chemical solution were greatly improved.

In the sapwood, the time required for the water content to reach 50% for both nitrogen gas and methanol was reduced to almost two thirds, and the time required for the hydrothermal treatment was reduced to four fifths. The time required for the water content to reach 25% was reduced to almost two thirds.

On the other hand, in Comparative Example 1, the gas pressure was set to 15 (kgf / cm ² ) without applying the temperature, but no improvement was observed in both the drying property and the chemical liquid impregnating property. In Comparative Example 2, the steaming treatment was performed at a vapor pressure of 1.2 (kgf / cm ² ) while maintaining the temperature at 120 ° C., and both the drying property and the chemical impregnation property were improved as compared with the untreated material. However, the characteristics of Example 2 were not obtained. In Comparative Example 3, the processing temperature was raised to 160 ° C. by changing the processing conditions of Example 2, and
Although the impregnating property of the chemical solution was improved, a decrease in strength and a change in material color were observed, and it was found that there was a problem in practical use.

From the above results, the preferred method of treating wall hole destruction in the present embodiment is that the temperature of 100-150 ° C., and preferably 120-130 ° C., in a closed pressure vessel is taken into consideration in consideration of the characteristics of the wood structure. Under a hydrothermal atmosphere, 30 (kgf / cm ² ) or less, preferably 5 to 15
(kgf / cm ² ) compressed air or compressed gas is used, and auxiliary suction is applied from the other end of the wood. According to such a processing method, a pressure gradient is applied to the wood, the closed wall hole is cleaved and broken, and free water in the material is forcibly dehydrated, so that the drying property and permeability of the wood can be increased. .

[0036]

[0037]

As described in detail above, according to the method for drying wood and the method for improving permeability according to the present invention, the closed wall hole of the wood is cleaved and broken by the pressure gradient applied to the wood. Because the free water inside is forcibly dehydrated,
Drying time until the wood reaches the predetermined moisture content in the sapwood portion can be greatly reduced. In addition, by performing the hydrothermal treatment on the core material, the drying time until reaching a predetermined moisture content is shortened as compared with the untreated material, and the material strength and color change of the material are minimized. It becomes possible to greatly improve the injectability of the chemical solution.

In particular, even softwood materials which are conventionally considered to be poor in drying property and chemical impregnating property are reduced and destroyed in closed wall holes. Therefore, the impregnated amount of chemical solution and the infiltration area are increased, and the drying time is reduced to about half. Can be shortened. In addition, by performing the above-described processing at the time of logging in the mountains, the weight of the temporary pipe due to dehydration of free water is reduced, and the problem of overloading during transportation by a vehicle can be addressed.

Further, according to the present invention, not only the drying time of the wood is shortened and the drying cost is reduced, but also the injectability of the chemical solution when improving the material quality of the wood is homogenized, and the drying of the wood is performed. This has the effect of speeding up the steps of processing, impregnation and the like.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a method of pressurizing and sucking wood at the tip of a wood used in the present invention.

FIG. 2 is a graph showing a change in water content (%) with respect to drying time of an example of the present invention and untreated wood.

FIG. 3 is a graph showing a change in moisture content (%) with respect to drying time of Examples and Comparative Examples of the present invention and untreated wood.

FIG. 4 is a cross-sectional view of a cedar material as an example of wood.

FIG. 5 is a schematic diagram illustrating a trunk structure of a tree and a process of growth.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Autoclave (closed pressure-resistant container) 2 ... Heating source 3 ... Upper cap 4 ... Lower cap 5 ... O-ring 6 ... Spring 7 ... (compressed air or compressed gas) container 8 ... Pressure valve 9, 11 ... Pipe line 10 ... Pressure adjusting valve 12 ... Gas trapping mechanism 13 ... Vacuum pump 15 ... Test material 20 ... Chamber

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kensuke Yamazaki 3992-3, Fushida, Kochi City, Kochi Prefecture Inside the Kochi Prefectural Industrial Technology Center (56) References JP-A-6-39807 (JP, A)

Claims (2)

(57) [Claims] 1. A wood fixed to a chamber formed in the inside of the sealed pressure vessel, together with press-fitting the one from the side of the timber end grain surface and compressed air or a compressed gas around timber closed pressure-tight container, closed pressure Compressed air from the other side of the container
A method for drying wood, comprising forcibly dewatering free water contained in wood by sucking compressed gas . 2. Wood is fixed in a chamber formed inside a sealed pressure-resistant container having a heating source on the outer periphery, and the sealed pressure-resistant container is heated by a heating source or heated by the introduction of steam, and simultaneously with the sealed pressure-resistant container. Compressed air or compressed gas is injected from one side of the container into the wood mouth and around the wood, and compressed air or compressed air is injected from the other side of the sealed pressure-resistant container.
Is a method for improving the permeability of wood characterized by sucking compressed gas .