JPH0638026B2 - Wood drying equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wood drying apparatus, and more specifically, for drying long cored wood that is preferably used as a decorative pillar such as a floor pillar or a decorative pillar. The present invention relates to a wood drying device.

(Prior Art) Decorative pillars such as floor pillars and decorative pillars used between floors in a Japanese-style building are used so that the outer peripheral shape and pattern of wood are used as they are, and the core material of wood is left as the decorative pillar. So-called core wood used as it is is generally used.

The core-bearing wood is previously subjected to a drying treatment, and this drying method includes a natural drying method and an artificial drying method.

Although the natural drying method is the most ideal as a drying method, it has the drawbacks that it is easily affected by the weather and that the time required for drying is extremely long, and the artificial drying method is currently the mainstream.

The hot air drying method is generally used as the artificial drying method. According to this method, the wood is placed in the drying chamber, and the heated dry air is forcibly supplied into the drying chamber so that the surface of the wood is dried.

(Problems to be Solved by the Invention) However, such a drying method has the following problems.

(1) When the wood surface is dried, the water contained in the wood is sequentially removed from the surface to the inside. In other words,
Moisture inside the wood is collected toward the surface side, but in this case, it takes a considerable time to dry the inside of the wood, that is, the core material portion to a predetermined water content.

(2) There is a large water gradient from the surface to the inside of the wood (see the broken line in Fig. 5), which tends to cause distortion.

(3) In addition to the characteristics of the moisture gradient, in the cored wood, the so-called peripheral material of the outer peripheral portion has a large shrinkage rate due to drying, while the so-called core material of the shaft core portion has a small contraction rate due to drying, Due to the difference in shrinkage, cracks are likely to occur on the wood surface. As a result, about 30% of defective products occur, and the product yield is extremely low.

(4) Due to the long drying time and poor yield,
This leads to higher product costs.

(5) In the case of artificial drying due to high temperature, the surface of the wood will be discolored, and surface cracks may occur, and if the drying conditions are moderated,
Mold on the surface of the wood will reduce its commercial value. In order to correct this, conventionally, acid chemicals or the like have been used to decolorize the surface of the wood, but this causes the original strength and durability of the wood to be greatly impaired.

(Means for Solving the Problems) The present invention is an apparatus for drying a core lumber in which a dorsal groove extending to the central portion of the core lumber is formed over the entire length, and the core lumber is inclined. In the state, holding means for holding the dorsal groove downward, a nozzle part installed in the dorsal groove so as to output gas in a direction orthogonal to the longitudinal direction, and a drying part for drying the nozzle part. Supply means for continuously supplying the working gas, discharging means for receiving the gas flowing through the dorsal groove and forcibly discharging it, and drying means for drying the discharged gas and transmitting it to the supplying means. And are characteristically provided.

(Operation) The nozzle portion has, for example, a nozzle round hole or an elongated hole, and outputs the drying gas in a direction orthogonal to the longitudinal direction of the dorsal groove. There are cases where the nozzle portions are opposed to each other over the entire length of the dorsal groove, and cases where they are opposed to each other.

The output drying gas moves from the periphery of the core lumber toward the center, and flows from the lower part to the upper part of the dorsal groove because the core lumber is inclined.

Therefore, the core material having a small shrinkage ratio due to drying and the peripheral material having a large shrinkage ratio are dried in parallel, and the drying process can be completed in a short time without causing a crack on the surface.

(Example) Hereinafter, the Example of this invention is described based on drawing.

Example 1 A wood drying apparatus according to the present invention is shown in FIG. 1, and the drying apparatus is of a type that specifically uses dry heated air as a drying gas, and includes a drying chamber 1, a dry air supplier 2, 2, the air dryer 3, the blower 4, etc. are provided as main parts. Further, the wood 5 to be dried by the drying device is provided with a gas flow passage 6 in a part of the outer circumference over the entire length.

The drying chamber 1 is a closed type formed in a rectangular parallelepiped shape, and the drying air supplier 2 is provided at the bottom of the drying chamber 1.
2 is provided, and the exhaust duct 7,
7 ... are provided.

The dry air supply device 2 is for supplying dry heated air to the woods 5, 5, ... Arranged in a leaning state in the drying chamber 1, and as shown in FIG.
It has a ... Tilt the wood 5 and let the gas flow groove 6
Is directed downward, the dry heated air blown to the lower end of the wooden piece 5 flows to the upper end so that the entire length of the wooden piece 5 can be uniformly dried. The injection nozzles 2a are arranged in a straight line in the vertical direction at a position corresponding to the lower end portion of the gas flow groove 6 of each wood 5, and four injection nozzles 2a are arranged at regular intervals. A plurality of sets are arranged in parallel in the lateral direction. Further, in the illustrated example, two dry air supply devices 2 are provided, but the capacity can be increased or decreased as appropriate according to the amount of dry processing.

The exhaust ducts 7, 7 are arranged above the upper ends of the timbers 5, ..., That is, directly above the upper ends of the gas flow grooves 6 ,. The number of installations is set corresponding to the number of the woods 5 ...
The exhaust ducts 7, 7, ... Are connected to the air dryer 3 via a pipe 8.
Is in communication with.

The air dryer 3 includes a dryer for cooling and drying the air from the exhaust ducts 7, 7 and a heat source such as an electric heater for heating the dried air. The air dryer 3 includes a pipe 9
Is communicated with the blower 4 via.

The blower 4 supplies the air dried and heated by the air dryer 3 to the dry air supplier 2 through the pipe 10.

Thus, in the above drying apparatus, the air dryer 3 is followed by the blower 4, the dry air feeders 2, 2, the gas circulation groove 6 and the exhaust duct 7, and the sealed dry air circulation is recirculated to the air dryer 3 again. The return circuit 11 is formed.

Next, the gas circulation groove 6 formed in the wood 5 will be described.

The gas circulation groove 6 is linearly provided on the circumferential surface of the wood 5 over the entire length. The cross-sectional shape of the gas flow groove 6 is
As shown in FIG. 3, the wood 5 has a rectangular shape toward the axis O. Further, the shape and size of the gas flow groove 6 is the same as the wood 5
The depth is set so as to be larger than the radius of the wooden piece 5, that is, to exceed the axis O, although the material and thickness of the wooden piece and the purpose of use are set. That is, the depth of the gas flow groove 6 is set to the radius of the wood 5 + α. For example, for wood 5 with a diameter of 120 mm, the above α
Is about 5 mm, that is, the depth is set to about 65 mm, and in the wood 5 having a diameter of 200 mm to 300 mm, the above α is 10
It is preferable that the depth is set to about mm, that is, the depth is set to about 110 mm to 160 mm.

Next, a method for drying wood using the wood drying apparatus configured as described above will be described.

At the position corresponding to the injection nozzles 2a of each set of the dry air feeders 2 and 2 in the drying chamber 1,
The drying device is operated after being placed in a leaning state as close as possible so that the dry heated air does not leak to the side.

The dry heated air from the air dryer 3 is forcedly circulated in the dry air circulation circuit 11 by the blower 4.

That is, the dry heated air is sent to the dry air supply device 2 and is sprayed from the spray nozzles 2a ... To the wood 5 ... (The wind speed at this time is set to, for example, 14 to 15 m / sec. .). This sprayed dry heated air is
As shown by the alternate long and short dash line in the figure, the wood 5 flows through the gas flow groove 6 upward from the lower end thereof and is forcibly discharged to the exhaust duct 7.

At this time, the dry heated air supplied into the gas flow groove 6 is, as shown by an arrow in FIG. 3, an inner wall 6 of the gas flow groove 6.
A, 6b, and 6c are blown onto the entire surface, and moisture inside the wood 5 is taken from the inner walls of these a, 6b, and 6c, and the taken water is discharged to the exhaust duct 7 along the gas circulation groove 6.
As a result, the core material having a small shrinkage rate due to drying and the peripheral material having a large shrinkage rate dry the wood 5 in parallel. However, since the circumference of the wood 5 (near the surface) has a large circumference, a large movement distance of water is required, while the movement distance of the central portion may be small, but according to the drying method by the device of the present invention, , You can get this delicately balanced and efficient drying.

Since the gas circulation groove 6 cuts the annual ring layer of the wood 5 in the radial direction, the dry heated air easily and evenly removes the water in each annual ring layer, whereby the wood 5 becomes the core material. It has a substantially uniform water content from
Almost no cracks were formed on the surface of the wood 5.

The air discharged from the exhaust duct 7 is sent to the air dryer 3, where it is dehumidified and heated, and the blower 4 is again used.
Is forcibly sent to the dry air supply devices 2 and 2, and this circulation is repeated thereafter.

Example 2 This example is shown in FIG. 4, and has a structure capable of drying a plurality of pieces of wood 5 ... Having different conditions such as thickness.

That is, in FIG. 4, the dry air supply device 2 includes a plurality of pipes 12 ... Independently arranged in parallel, and a set of injection nozzles 2a. It is said to have a different structure. Conditions such as the temperature and humidity of the dry heated air fed to each of the pipes 12 are set separately, and for example, wood 5 to be dried.
Depending on the thickness of the wood, the time to cut down, etc., for each wood 5 ...
And the conditions are set according to usage.

Then, by arranging the woods 5 of different types and uses for each of the above-mentioned pipes 12 side by side in an inclined state in parallel,
Since each wood 5 is dried under the optimum conditions, it is possible to suitably cope with the small-lot production of a wide variety of products in accordance with the diversification of demands, and the conditions of different dryness are given individually.

Other structures and operations are similar to those of the first embodiment.

Next, the result of the test conducted to examine the effect of the drying treatment by the drying device of the present invention will be described.

The wood drying apparatus having the structure of Example 1 is used, and the wood 5 to be dried is a cedar material for floor pillars, and its specific standard is as follows (see FIG. 3).

Standard 1. Length of cedar wood 5: 300 cm 2. Diameter of cedar wood 5: 120 mm 3. Width W of gas flow groove 6: 5 mm 4. The depth L of the gas flow groove 6 is 65 mm. The gas flow groove 6 also serves as a sock.
The wood has a diameter of about 20 at the end opening (upper part when standing up) and the base opening (footing of the standing scaffolding) for a length of 300 cm.
Although there is a difference of about mm, the depth of the dorsal ridges at both the front and end openings is formed by +5 mm of wood.

The cedar material 5 processed in this way is placed in the drying chamber 1 of the drying device.
75 pieces were accommodated in a leaning state, and dry heated air (humidity 50%, temperature 40 ° C.) was supplied for 48 hours from the spray nozzles 2a, 2a of the dry air feeders 2, 2.

The cedar material 5 obtained as described above had a water content of 50% and a total dry weight of 34 kg / m ³ , and the outer peripheral surface thereof was not cracked at all and satisfied all the conditions for floor columns. Moreover, the surface of cedar wood used as a floor pillar is usually bleached with a bleaching agent, but the cedar wood 5 dried by the method of the present invention can be directly applied as a floor pillar without bleaching.

This is because the water inside the cedar wood 5 gathers in the gas flow grooves, that is, the dorsal fins 6, so that the surface of the cedar wood 5 has a color close to white, and bleaching is not necessary.

The present invention is not limited to the above embodiment.

For example, in order to allow the dry heated air to flow through the gas circulation groove 6 of the wood 5, as shown in FIG. 1, the wood 5 is supported in a leaning state and the air is sent from the lower end portion of the gas circulation groove 6. Although it is efficient, it is not always limited to this, and the wood 5 may be supported in an inclined state. Particularly, it is preferable when the length of the wood 5 is 400 cm to 600 cm, which is considerably long.

(Effects of the Invention) As described in detail above, the present invention is an apparatus for drying a core lumber that forms a dorsal groove extending to the center of the core lumber over the entire length, and a holding means, Nozzle part,
Since the supply means, the discharge means, and the drying means are provided, the wood can be dried from the inside, and the occurrence of cracks on the wood surface can be prevented. Is obtained, and extremely excellent artificial drying is possible.

(1) Unlike the case of drying from the surface of wood as in the past, by drying from the gas circulation groove (backward), the center part of the wood and the outer peripheral part are dried in parallel, so that it can be done in a short time. It is possible to dry the entire interior of the wood to a predetermined water content.

(2) In the drying method using this drying device, the water gradient after the drying process is small and has a very gentle gradient from the surface to the inside of the wood as shown by the solid line in FIG.
Therefore, there is not much difference in water content from the surface of the wood to the inside, and the wood quality inside the wood becomes uniform.

(3) In addition to the characteristics of the moisture gradient, not only the peripheral material having a large shrinkage rate due to drying but also the core portion having a small shrinkage rate due to drying is dried at the same time. Since the wood is cut, the water contained in each annual ring layer is efficiently and evenly released, the wood surface is not cracked, and therefore the defective product is hardly generated, and the product yield is very good. By the way, the conventional crack occurrence rate was about 30%, but it became about 2% by implementing the present invention.

(4) Due to the short drying time and good yield,
Product cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing a wood drying apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view showing a relationship between a dry air feeder of the drying apparatus and wood, and FIG. A sectional view taken along the line III-III, FIG. 4 is a drawing corresponding to FIG. 2 showing a dry air supply device of Example 2, and FIG. 5 is a moisture gradient of wood dried by the drying apparatus of the present invention. FIG. 6 is a diagram showing a comparison with a water gradient obtained by a conventional drying method. 1 ... Drying room, 2 ... Dry air supply device (dry gas supply device), 2a ... Injection nozzle, 3 ... Air dryer (gas drying device), 4 ... Blower, 5 ... Wood, 6 ... … Gas flow groove, 7 …… Exhaust duct, 8,9,10 …… Pipe, 11 ・ ・ ・
… Dry air circulation circuit

Claims (4)

[Claims] 1. A device for drying a core lumber having a dorsal groove extending to the central portion of the core lumber over the entire length thereof, wherein the core lumber is inclined and the dorsal groove is formed. Holding means for holding downward, a nozzle portion installed to output gas in a direction orthogonal to the longitudinal direction in the dorsal groove, and a supply for continuously supplying a drying gas to the nozzle portion Means for receiving the gas flowing through the dorsal groove and forcibly discharging the gas, and a drying means for drying the discharged gas and transmitting the gas to the supply means. Wood drying equipment. 2. The wood drying apparatus according to claim 1, wherein the drying gas is dry heated air. 3. The nozzle according to claim 1, wherein the nozzle portion is formed from the lower end portion to the upper end portion of the cored lumber over a lower portion ⅓ or more of the entire length. The described wood drying apparatus. 4. The wood drying apparatus according to any one of claims 1 to 3, wherein the supply means is capable of appropriately changing the supply amount of the drying gas.