JPH0117843B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention was developed to shorten the drying period of wood that is left unused for a long time after felling, such as easily cracked black sputum, and to shorten the period of injecting it into the wood. It is.

Recently, lumber companies have been using logs and sawmills that they obtain, such as black tongue, for a long period of time after felling, to obtain logs that do not have free water from the beginning or where free water has partially disappeared. It has become necessary to buy what is available.

Even if the free water has disappeared from the beginning, if the resin remains attached to the conduits or other parts of the wood that are related to the movement of the contained water, capillary action will not occur easily, and air-drying or drying will occur. Cracks tend to occur during drying. In addition, shrinkage occurs where free water is lost, and the presence of resin makes drying difficult, and it is also difficult to make high moisture content wood injected with water or an aqueous solution, or wood injected with chemicals. It's becoming difficult. Even if you try to boil the wood for slicing, if the condition is such that it is difficult to produce wood with a high moisture content, the boiling period will be extremely long, which is extremely inconvenient.

Conventional pressure injection and vacuum injection methods cannot inject uniformly even when free water remains, but it takes a long time to inject wood that has no free water and is shrinking. It is almost impossible to inject evenly.

For some time now, the method of boiling free water and removing resin from wood using the SV method or vacuum drying method has been based on the assumption that free water exists within the wood.
For wood where free water has partially disappeared,
This construction method will not work. Even if steam is injected into the wood using steam pressurization, it is impossible to create free water uniformly in areas where shrinkage occurs, as well as in other areas.

If wood is heated with high-pressure steam using a pressure vessel, the cage pressure of the steam will be 1 Kg/ ^cm2 , and some wood species will shrink, so the pressure limit for steam heating depends on each wood species. However, wood heating using steaming and air heating has the drawback that there is a temperature limit for heating the wood due to the occurrence of cracks. When used, a pressure reduction effect occurs even in the process of releasing saturated steam heated to the heating temperature limit outside the pressure vessel and reaching atmospheric pressure, but that pressure reduction effect alone is insufficient, so from the time the pressure reduction effect occurs, Destruction of only the cell cavity, which has extremely small pores inside the cell cavity, made drying and injection difficult because it required a vacuum process using a vacuum pump that was incomparably slow. It also had the disadvantage that it was difficult to produce a depressurizing effect.

Wood, especially wood that has shrunk in whole or in part due to the loss of free water, can be dried uniformly throughout the wood in a short time to prevent cracking, and to reduce processing time to make boiling and infusion wood for slicing. It has become necessary to develop a process that creates free water and removes the resin that was an obstacle to the release of the free water and the creation of injected wood.

The present invention was developed to solve the above-mentioned problems, and while an embodiment thereof will be explained in detail, problems that will arise when implementing the embodiment will also be explained at the same time.

Place the wood in the water tank attached to the pressure vessel, make sure it does not float up, then fill the tank with hot water, close the door, and inject high pressure steam into the pressure vessel at the bottom of the tank and outside the tank to cool the inside of the tank. is high-temperature water at a predetermined temperature of 110 to 150℃, and the gauge pressure outside the tank is, for example, 1.
~6Kg/cm ² High pressure steam is used at a pressure that does not cause high temperature water to boil. The predetermined pressure and predetermined temperature may be lower for wood whose cell cavity walls are thin at a temperature just below the boiling temperature, but for wood whose cell walls are thick, it is easier to obtain better results if they are higher. .

Even if the water tank is pressurized with high-pressure steam in a pressure vessel and the temperature of the water in the water tank becomes higher than the boiling point of atmospheric pressure, the temperature of the high-temperature water in the tank is difficult to become uniform, so some of this saturated steam is released and the high pressure If steam is alternately injected outside the water tank, the steam pressure commensurate with the temperature of the high-temperature water is minimized, and the saturated steam pressure is frequently fluctuated.
When the saturated vapor pressure decreases, the high-temperature water in the water tank comes to a state just before boiling, and the temperature unevenness of the high-temperature water can be easily corrected. Also, the high temperature water in the aquarium will seep into the wood and evaporate, causing the water level to drop.If high-pressure steam is injected from the bottom of the tank, the water level will rise and the temperature unevenness can be easily corrected. .

If wood is left exposed to high-temperature water that is above the boiling point of atmospheric pressure under high-pressure steam, the wood will expand and the resin attached to the pipes will become soft, increasing the gaps in the pipes. . When the pressure of this high-pressure steam is changed frequently, high-temperature water is injected into the wood when the high-pressure steam pressure is high, and when the pressure is reduced, the air and water contained in the wood are The high-temperature water that enters the wood and has a lower temperature rebounds toward the surface layer, so after a predetermined time, the interior of the wood is filled with high-temperature water and reaches a predetermined temperature.

Generally, when wood is heated using pressurized heating using saturated steam, the shrinkage rate of the wood begins to increase if it is heated at a steam pressure of 1 kg/cm ² and a temperature of 120°C or higher. In wood heating using this high-temperature water, the pressure of the high-temperature water that has penetrated into the wood and the pressure of the high-temperature water outside the wood are equalized, so the wood is less likely to be compressed by pressure, and further Heating to a high temperature does not increase shrinkage, and depending on the wood species, the shrinkage rate increases only when the heating temperature reaches 145℃ or higher in experiments, so it is more effective than heating with saturated steam. , the wood temperature can be made very high. Theoretically, it is unlikely that shrinkage will occur above 145℃, but depending on the wood species,
Given the above, it is thought that the reason why there are some products that cause shrinkage is that shrinkage occurs when pressurized high-temperature water is released.

After heating the wood to a predetermined temperature, when the high-temperature water that is no longer needed begins to be released outside the pressure vessel to remove it, the pressure inside the pressure vessel begins to decrease and the high-temperature water Boiling occurs, and as the water level of the high-temperature water drops, the water contained in the wood that rises above the high-temperature water level also boils, and as a result of that boiling,
The temperature of the wood and high-temperature water also decreases, and after the water contained in the wood boils and evaporates, the low-temperature water enters the wood due to capillary action, and at the same time, the temperature of the wood further decreases, and at the same time, the high-temperature water cools the wood. The benefits of heating are offset.

For this purpose, the unnecessary high-temperature water can be removed without boiling it as follows. At the same time as this unnecessary high-temperature water begins to be discharged outside the pressure vessel, high-pressure steam is injected outside the water tank, and the inside of the pressure vessel is
The high temperature water in the tank must be released while maintaining a saturated vapor pressure commensurate with the predetermined temperature. This process replaces the high-temperature water that circulates around the wood with saturated steam without boiling the high-temperature water or the high-temperature water that has entered the wood, and without lowering the temperature. By temporarily changing the pressure of the replaced saturated steam to match the temperature of the heated wood over a small width in the center, the high-temperature water remaining on the surface of the wood is gradually removed, and the pressure inside the pressure vessel is gradually changed. As a result, high-temperature water is completely discharged, and only saturated steam at a predetermined temperature surrounds the wood.

After that, when saturated steam is started to be released from the pressure vessel, unlike the release of high-temperature water, saturated steam can be released rapidly. This causes the problem of increased shrinkage, which causes the wood to heat to a high temperature that cannot be heated with saturated steam. Under depressurized conditions, the water contained in the wood and the high-temperature water that has entered the wood are reduced from the pressure corresponding to the high temperature to atmospheric pressure.
It boils rapidly, and before the pressure inside the pressure vessel reaches atmospheric pressure, the vapor pressure inside the wood caused by this boiling causes the resin attached to the walls of the wood pipes to chemically decompose through steam distillation. The decomposed resin is pushed out to the surface of the wood by the boiling pressure, improving the quality of the wood by removing the resin that was causing inhibition of drying and pouring.

In the commonly used SV method, the pressure is generally limited to 1Kg/cm ² due to the problem of wood shrinkage, and then pressurized steam is released and a vacuum pump is used to apply pressure to -0.7Kg/cm2. The general operating method is to reduce the pressure to ^cm2 . This is 1.7Kg/cm ² from overheating.
Since the pressure drop is only 50 minutes, and since the operation of a vacuum pump must be used, this pressure drop takes more than 40 minutes, so it is a relatively gradual pressure drop. On the other hand, in the method of the present invention, for example, if the heating temperature of high-temperature water is 138°C, the amount of pressure reduction from the corresponding boiling point pressure to atmospheric pressure is approximately twice that of the SV method, and the amount used for the pressure reduction is approximately twice that of the SV method. The boiling pressure of the heated water in the cell cavities in the wood is incomparable to that in the SV method, as the pores, which are the exits of the cell cavities, are smaller. If the process of the present invention is used, the wall of the cell cavity, which has extremely small pores inside the cell cavity, which has been difficult to dry and inject, can be easily destroyed, which may have the side effect of making it easier. .

The wood made using the wood material improvement method of the present invention is placed in a pressure vessel or is kept in a pressure vessel, hot water is poured into the water tank, the outside of the water tank is filled with saturated steam, and the saturated steam pressure is increased to 1 to 3 kg. With a pressure width of /cm ² ,
If the vapor pressure is varied, the resin that made injection difficult will disappear, and the wall of the cell cavity, which is the part that is difficult to inject, will have extremely small pores. is destroyed, so it is easy to achieve a uniform high moisture content. Using this high-moisture-content manufacturing method, chemical-infused wood can be easily produced by using an aqueous chemical solution instead of hot water.

As explained in the above embodiments, the present invention has a water tank containing high-temperature water at a predetermined temperature of 110 to 150°C and wood inside the pressure vessel, and a high-pressure system outside the water tank where the high-temperature water does not boil. Even if you turn it into steam, vary this high-pressure steam pressure, inject high-temperature water into the wood, bring the temperature of the wood to a predetermined temperature, and then release this high-temperature water outside the pressure vessel, the wood will not maintain the high pressure at this predetermined temperature. After performing a high-temperature water release method characterized by being surrounded by steam, high-pressure steam at a predetermined temperature is released outside the pressure vessel to create a phenomenon that boils the high-temperature water or water contained within the wood. , is a wood material improvement method characterized by removing resin adhering to the walls of wood conduits etc. using the vapor pressure generated by this boiling, and after implementing this wood material improvement method. By pouring hot water into the water tank, making the outside of the water tank saturated steam, and applying pressure that changes the pressure of the saturated steam, hot water can be injected into the conduits and cell cavities of wood. The wood made from this method has no resin that was a barrier to the release of water contained in it and the injection of aqueous solutions or hot water, making it a wood that easily absorbs water. When this was carried out, it became possible to easily destroy the wall of only the cell cavity, which had extremely small pores as a byproduct.

With the development of this wood material improvement method, even wood that has lost all or part of its free water, which is difficult to remove even with steam treatment such as the SV method, can be treated by injecting high-temperature water into the wood. Free water is created in the process, and resin attached to the walls of conduits etc. can be removed, so when drying, regardless of whether or not shrinkage occurs due to the presence of free water,
Because it is easily compatible with water, capillary action occurs easily, and the water contained in the cell cavity, which has extremely small pores that made it difficult to release the water, can be easily released from the area where the cell cavity has been destroyed. This makes it easier to dry without causing cracks.

In addition, with the development of this method for improving the quality of wood, wood species such as black sardines that required a long time to be boiled for slicing, and wood that had a low moisture content, can now be heated to a high moisture content by injecting hot water. In order to make the resin, the resin that was an obstacle to injection has been removed, and only the cell cavity, which has extremely small pores, has been destroyed. By adding wood treated with this method and hot water and varying the pressure of saturated steam outside the water tank, high moisture content wood can be easily produced, and the traditional boiling time for slicing can be reduced to less than 10%. It became.

By using the wood material improvement method of the present invention, wood injected with an aqueous solution of chemicals can be easily produced, which not only shortens the production time of injected wood but also eliminates the need for chemicals to promote injection, significantly reducing manufacturing costs. Now I can do it.

As explained above, the present invention provides various production benefits and is of great benefit to the industry.

Claims (1)

[Claims] 1 In a pressure vessel, the high-temperature water in the water tank containing the wood is turned into high-pressure steam that does not boil, and the pressure of the high-pressure steam is varied to provide high-temperature water at a predetermined temperature of 110 to 150°C, and then the wood is Even if the high-temperature water is released outside the pressure vessel, it is still surrounded by high-pressure steam at the predetermined temperature, and then the high-temperature water that has entered the wood is released by releasing the high-pressure steam outside the pressure vessel. Creates the phenomenon of boiling water and contained water,
A method for improving the quality of wood, characterized in that resin adhering to the walls of conduits, etc. of the wood is removed by water vapor generated by the boiling.