JPH045985Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an apparatus for drying a thin veneer with a high moisture content after dyeing and controlling the humidity to within a standard moisture content.

[Background Art] In the manufacturing process of plywood, veneers are bonded and formed using a moisture-curing adhesive, so it is necessary to adjust the moisture content of the veneer to be within a certain standard. For example, the moisture content of the veneer after dyeing is 265
±35%, which needs to be adjusted to 24±12%. However, the drying capacity of conventionally used steam hot air net dryers is 180 to 220%.
With this processing capacity, the dyed veneer moisture content is 265 ± 35% and the dry finished moisture content is 28 ± 24%, but the drawback is that the drying humidity control ability is low and it is not possible to finish the veneer to the desired specifications. It was hot. Therefore, it is not possible to adjust the moisture content to suit moisture-curing adhesives, resulting in poor adhesion of veneers and poor glazing. ), and since it is an indirect drying method that blows hot air, the drying cost is also very high.

[Purpose of the invention] The present invention was developed in view of the technical background described above, and its purpose is to provide a veneer drying control system with high drying and humidity control abilities and low drying costs. Provides moisture equipment.

[Disclosure of the invention] The veneer drying and humidity control device of the present invention compresses and heats the veneer 1 with upper and lower rotatable heating rolls 2 facing each other, and generates heat that dries the veneer 1 to an overdry state. A roll dehydrator 3, a moisture content sensor 4 that detects the moisture content of the veneer 1 after passing through the hot roll dehydrator 3, and a moisture content sensor 4 that detects the moisture content of the veneer 1 after passing through the heated roll dehydrator 3, and supplies moisture that is insufficient than a predetermined moisture content to the overdried veneer 1. It is characterized by comprising a moisture supply device 5 that adjusts the moisture content of the veneer 1 to a predetermined moisture content, and by adopting a direct heating method and adding a squeezing dehydration effect, it is possible to achieve a low cost yet high cost. The drying ability can be exhibited, and the moisture content can be finally adjusted by the moisture supply device after the moisture content is detected by the moisture content sensor, so that it has a high humidity control ability.

(Embodiment) A first embodiment is shown in FIG. 1, and is composed of a hot roll dehydrator 3, a moisture content sensor 4, and a moisture supply device 5 consisting of two water spray devices 6. . First, the hot roll dehydrator 3 will be explained. 2
are a pair of upper and lower rotatable heating rolls that face each other vertically with a gap (distance between the heating rolls 2 during veneer pressing) that is smaller than the thickness of the veneer 1 (thickness before pressing). It is being In addition, the heating roll 2 has a high temperature, and its surface temperature is, for example, 200°C.
The temperature can be controlled within the temperature range. A plurality of such upper and lower pairs of heating rolls 2 are arranged in multiple stages. In the illustrated example, there are 6 stages (No. 1,
No.2...No.6). Veneer 1 before drying
has a high moisture content due to chemical treatments such as dyeing and bleaching, for example, the initial moisture content is 265±35
%. Thus, the wood veneer 1 is fed into the heating roll 2 along the fiber direction of the veneer, and is compressed and dehydrated by the heating roll 2 (squeezing effect) and heated on the surface of the heating roll 2. It is dried (direct heating effect), and as shown in the graph of Figure 2, it is processed with high drying efficiency at each stage, and the moisture content is adjusted to about 10% or less, reducing the variation in moisture content. Further, the surface of the veneer 1 is finished smooth by pressing. The feeding speed of heating roll 2 at this time is
Although the speed is set at 15 m/min, this may vary depending on material factors such as board thickness, wood species, and specific gravity, or drawing conditions of the heating rolls 2 such as roll temperature and gap between rolls. In this way, the hot roll dehydrator 3 not only heats and dries the veneer 1 with a lot of floating water.
Since the veneer 1 is squeezed to remove water, a large amount of latent heat of vaporization is not required, and the veneer 1 with a high moisture content can be effectively dried at a low drying cost. Moreover, the veneer 1 is softened by being heated,
It also has the synergistic effect of requiring less clamping force for dewatering. 4 is a moisture content sensor placed in front of the hot roll dehydrator 3; for example, a far-infrared sensor or a microwave moisture content meter is used. Veneer 1
While the water content is detected by the water content sensor 4, it passes through the water content sensor 4 and is sprayed into the water spray device 6.
A certain amount of water (76 gr/m ² ) is evenly applied from the top and bottom of the veneer 1 whose moisture content is 10%, and the moisture content is adjusted to 24±12.5%. Finally, the moisture content sensor 4 at the front detects the moisture content as 24±12.5.
%.

The device shown in FIG. 3 is another example of the present invention, in which the moisture supply device 5 is constructed by two pairs of sponge rolls 7. As shown in the graph of FIG.
The veneer 1 is finished with a small variation of ±4%, and the moisture content sensor 4 detects this moisture content of 8±4%.
The operator is notified of any veneer 1 that is out of this setting range and whose humidity cannot be controlled, and the operator removes the veneer 1 to ensure the moisture content.

[Effects of the invention] Since the invention is constructed as described above, the veneer can be pressed with heated rolls to squeeze out moisture.
Even veneers with high moisture content can be dried at low cost without requiring latent heat of vaporization.Additionally, by adding a heating drying method to this method, high drying ability can be demonstrated and veneers can be dried using heat. It has the advantage of softening and making it easier to press the veneer. In addition, the veneer is compressed and heated using a hot roll dehydrator to dry the veneer to an over-dry state, so over-drying can reduce variations in the moisture content of the veneer. Moreover, after that, the moisture content of the veneer is detected by a moisture content sensor, and the moisture that is insufficient than the predetermined moisture content is supplied to the overdried veneer to adjust the moisture content of the veneer to the predetermined moisture content. It has the advantage of keeping the moisture content constant.

[Brief explanation of drawings]

FIG. 1 is a schematic overall diagram showing an embodiment of the present invention;
Figure 2 is a graph showing the transition of moisture content in each step of the same as above, Figure 3 is a schematic overall diagram showing another example of the present invention, and Figure 4 is a graph showing the transition of moisture content in each step of the same as above. , 1 is a veneer, 2 is a heated roll, 3 is a heated roll dehydrator, 4 is a moisture content sensor, 5 is a moisture supply device, 6 is a water spray device, and 7 is a sponge roll.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A hot roll dehydrator that dries the veneer to an overdry state by compressing and heating the veneer with upper and lower rotatable heating rolls facing each other, and a hot roll dehydrator. A moisture content sensor that detects the moisture content of the veneer after passing through the machine, and a moisture supply device that controls the moisture content of the veneer to a predetermined moisture content by supplying moisture that is less than the predetermined moisture content to the overdried veneer. A veneer drying and humidity control device consisting of. (2) The veneer drying and humidity control device according to claim 1, wherein the moisture supply device is constituted by a water spray device that sprays water onto the veneer. (3) The veneer drying and humidity control device according to claim 1, wherein the moisture supply device is constituted by a sponge roll that applies water to the veneer.