JPS6318110B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for drying green veneers, which can perform tenderizing on green veneers and also perform hot plate drying more effectively than conventional methods.

Compared to hot air drying, hot plate drying uses contact heating with a hot plate, so drying time is shorter and thermal efficiency is better.
In addition, shrinkage in the direction perpendicular to the fiber direction of the raw veneer due to drying is suppressed, improving the yield and producing a flat finish.However, conventional hot plate drying uses a flat hot plate. It is necessary to open the hot plate during drying to diffuse the evaporated moisture, resulting in a decrease in efficiency and drying shrinkage, which is suppressed compared to around 7% with hot air drying, but shrinkage of 2 to 3%. In addition, dry veneers that had been finished flat also developed cracks over time due to uneven moisture content, differences in moisture absorption, material quality, etc., and there were other difficulties such as the need for tenderizing for post-processing.

This invention has been developed in view of the above-mentioned difficulties in hot plate drying. Hot plate drying is achieved by forming a large number of concave and convex portions, and applying pressure and heating to the raw veneer in a curved manner by aligning the direction of the concave and convex portions with the fiber direction of the raw veneer. It increases efficiency and efficiency, almost eliminates drying shrinkage, and improves yield.In addition, tenderizing is applied to generate fine cracks in the direction of the fibers on both the front and back sides of green veneer, or only on the surface, to prevent subsequent lateral This allows smooth processing in the stripping or gluing process.

The first invention has relatively little cracking on the back of raw veneer,
This method is applied when it is necessary to perform tenderizing on both the front and back sides of a raw veneer, and this will be explained below with reference to embodiments shown in FIGS. 1 to 4. 1 is the upper heating plate, 2 is the middle heating plate (only one middle heating plate 2 is shown, but usually there are more than one), 3 is the lower heating plate, and each heating plate 1 ,2,
3 is heated by an appropriate heat source such as steam, hot water, or a heater, and the upper heating plate 1 and the intermediate heating plate 2
is constructed so that it can be opened and closed by an operating mechanism 4 such as a fluid pressure cylinder.

The opposing plate surfaces of each of the hot plates 1, 2, and 3, that is, the upper plate surface 2F of the intermediate hot plate 2, the lower plate surface 1B of the upper hot plate 1, and the upper plate surface 3F of the lower hot plate 3. A V groove (curved groove A large number of concave portions 5 and concave portions 6 are continuously formed in the form of , a protrusion 7 having a shape that faces and fits into the recess 5, and a protrusion 8 having a shape that faces and fits into the recess 6, respectively. In this case, since the recesses 5 and 6 are formed continuously, a projection 7' is formed between adjacent recesses 5, a projection 8' is formed between adjacent recesses 6, and A recess 5' is formed between adjacent projections 7, and a recess 6' is formed between adjacent projections 8. ,8,
8' respectively form curved pressing and heating surfaces.

Guide plates 9 are provided on the sides of the hot plates so that when the hot plates 1 and 2 are opened and closed by the actuating mechanism 4, the opposing uneven portions coincide and thereby perform pressurized heating in a bent shape. to guide each hot plate 1, 2. In addition, when inserting the green veneer A between the hot plates, as shown in FIG. (Figure 3) (Direction perpendicular to the page in Figure 1)
The hot plate is closed by the actuating mechanism 4 as shown in Fig. 2, and the green veneer A is pressed and heated in a curved shape by the pressure surface of the uneven part to dry it. Do it.

In this case, the bending of the raw veneer A is parallel to the fiber direction, and the raw veneer A is flexible in the direction of this bending, so it will not be damaged in any way, and the opposing uneven parts will fit into each other. Because they are formed so that they fit together, the surface of the green veneer comes into close contact with the surface of the board, allowing for highly efficient drying. Furthermore, as shown in Fig. 4, due to the bending pressure applied by the uneven parts, a tensile force acts on the green veneer surface on the recessed part side (recessed parts 5, 5'), causing many small cracks 1.
0 occurs, and these cracks 10 are formed into elongated grooves that match the fiber direction of the green veneer A, producing the same effect as when tenderizing is applied. Since the moisture can be easily diffused, there is no need to open the hot plate to diffuse evaporated moisture during drying, and the efficiency and efficiency of hot plate drying is therefore greatly improved.
In addition, when each uneven portion is formed in a polygonal shape as in the embodiment, voids 11 are formed in each of the recesses 5 and 5', and these voids 11, together with the cracks 10, serve as passages for evaporated moisture. , the evaporated water can be diffused more effectively. In addition, shrinkage due to drying of green veneer A mainly occurs in the direction perpendicular to the fiber direction, but this shrinkage is prevented by the pressure applied by the hot plate and the resistance caused by the bending of the uneven parts.
Since the shrinkage is absorbed by the many cracks 10 that have occurred, drying occurs with almost no shrinkage, and the yield is greatly improved.

The second invention is applied when a green veneer has many cracks on the back side and there is no need to tenderize the back side, and this is carried out as shown in FIGS. 5 and 6. To explain with an example,
12 is an upper heating plate, 13 is an intermediate heating plate, and 14 is a lower heating plate. Each of the heating plates 12, 13, and 14 is heated by an appropriate heat source, and can be opened and closed by an operating mechanism 15. It is configured. Then, a large number of V-groove recesses 16 and recesses 1 are formed in the same direction on one of the oppositely facing plate surfaces, for example, the upper plate surfaces 13F and 14F of the middle heating plate 13 and the lower heating plate 14, respectively.
7 is formed through a flat plate part 18 and a flat plate part 19, and the recesses 16 and 17 are formed on the lower plate surfaces 12B and 13B of the upper heating plate 12 and the intermediate heating plate 13, which are the other plate surfaces. Convex portions 20 and 21 are formed so as to face and fit therewith, and flat plate portions 22 and 23 are formed opposite to the flat plate portions 18 and 19. When the upper and middle heating plates 12 and 13 are opened and closed by the guide plates 24 provided on the sides of the heating plates, the opposing uneven portions coincide and press the green veneer A' in a curved manner. Each hot plate 12, 13 is guided so that heating can be performed.

When inserting raw veneer A' between the hot plates, with the hot plates open, make sure that the fiber direction matches the direction of each recess 16, 17, and that the back cracks 2 of raw veneer A' are aligned.
5 so that the ungenerated surface S faces the plate surface having the concave shape (upper plate surfaces 13F and 14F), the hot plate is closed by the actuating mechanism 15, and the green veneer A' is heated. Drying is performed by applying pressure and heating in a meandering manner using the uneven portions. In this case, there is a large number of back cracks 25 on the back side of the raw veneer A', and there is no need for softening, and it is only necessary to tenderize the surface S.
Pressure is applied to the concave portion 1 as shown in Fig. 6.
A large number of fine cracks 26 are generated on the surface S at portions 6 and 17. These cracks 26
As in the case of the first invention, the grooves serve as passages for evaporated moisture, and when the recesses 16 and 17 are formed into V-grooves, voids 27 are also created, allowing the evaporation moisture to easily diffuse and separate from the uneven portions. Because the flat plate is in close contact with the surface of the green veneer, highly efficient drying is possible, and drying with almost no shrinkage can be achieved by applying pressure with the hot plate, resisting the uneven parts, and absorbing shrinkage due to cracks. It is.

As described above, in the present invention, uneven portions are formed on the oppositely facing surfaces of hot plates, and a green veneer is inserted between the hot plates so that its fiber direction matches the direction of the concave portions, and the green veneer is bent into a curved shape. Because it uses pressure and heat, it is possible to dry and tenderize raw veneer at the same time, saving labor in the plywood manufacturing process, and it also makes hot plate drying more efficient, contributing to energy savings. Moreover, it has many advantages such as improved yield due to the drastic suppression of drying shrinkage, making a great contribution to the synthetic industry.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the first invention, and FIG. 1 is a front view with the hot plate in an open state;
Figure 2 is a front view with the hot plate closed, Figure 3 is an explanatory diagram showing the relationship between the fiber direction of the raw veneer and the direction of the recess when the raw veneer is inserted between the hot plates, and Figure 4 is an explanatory diagram showing the state when a green veneer is pressed by a hot plate, FIGS. 5 and 6 show an embodiment of the second invention, and FIG. 5 is a front view when the hot plate is open. FIG. 6 is an explanatory view showing a state when a raw veneer is pressed by a hot plate. 1, 2, 3...hot plate, 1B, 2B...lower plate surface,
2F, 3F...Top plate surface, 4...Operation mechanism, 5,
5', 6, 6'...Concavity, 7,7',8,8'...Protrusion, 9...Guide plate, 10...Crack, 11...Vacancy, 12,13,14...Heat Board, 12B, 13B
...Lower board surface, 13F, 14F...Upper board surface, 15...
...Operating mechanism, 16, 17... Recess, 18, 19,
22, 23... flat plate part, 20, 21... convex part, 2
4... Guide plate, 25... Back crack, 26... Crack, 27... Blank space, A, A'... Raw veneer, S...
surface.

Claims (1)

[Scope of Claims] 1. A plurality of V-groove-shaped recesses are continuously formed in the same direction on one opposing plate surface of a plurality of heat plates configured to be openable and closable, and on the other plate surface. , forming a convex portion facing each of the concave portions and having a shape to fit therewith;
Drying of a green veneer that also serves as tenderizing, characterized by inserting the green veneer between hot plates so that the fiber direction of the veneer matches the direction of the recess, and applying pressure and heating in a bent shape using the uneven parts. Method. 2 A large number of V-groove-shaped recesses are formed in the same direction on one of the opposing plate surfaces of a plurality of heat plates configured to be openable and closable, with a flat plate interposed between each recess, and the other plate surface is In this step, a convex portion having a shape that faces each of the concave portions and fits therein is formed, and the green veneer is made such that the fiber direction thereof matches the direction of the concave portions, and the surface of the green veneer is aligned with the concave portions. A method for drying green veneer that also serves as tenderizing, which is characterized by inserting between hot plates so as to face the formed board surface, and applying pressure and heating in a curved shape using uneven parts.