JP2001165573A - Veneer single plate drier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out dried single plates of desired finished percentage of moisture content even if single plates different in initial percentage of moisture content are mixed. SOLUTION: This drier measures the initial percentage of moisture content being the percentage of a raw single plate 3a with a high frequency moisture content meter 4, at the point of time of carrying plates into a drying chamber 1, and computes the required drying time required to dry the plates until they come to the desired finished percentage of moisture content with a controller 5, based on the data of at least the initial percentage of moisture content, the temperature within the drying chamber, the kind of wood, and the thickness, and controls the velocity to the carriage velocity corresponding to the computed required drying time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a veneer veneer drying apparatus such as a continuous drier for drying veneer veneers and a roll drier for small veneers.

[0002]

2. Description of the Related Art Conventional veneer veneer dryers first measure the initial moisture content, which is the moisture content of the green veneer, on the carry-in side, and then pass the green veneer through the dryer to the carry-out side. Based on an empirical rule, set the feed rate at which the dried veneer is expected to have the desired finish moisture content at the time of arrival, and calculate the finish moisture content of the dried veneer actually dried at the set feed rate. The moisture content was detected by a formula, and the data of the finished moisture content was fed back to the loading side, and the transport speed was adjusted so that the moisture content of the subsequent dried veneer approached the finished moisture content.

[0003]

Even if a dried veneer having a desired finish moisture content is carried out, the moisture content of the raw veneer varies depending on various factors, and in the case of a rolled ball, the moisture content increases as it approaches the core. And if it is a small veneer,
The moisture content of the raw veneers to be carried in is not constant because the tree species and thickness are different, and the moisture content of the veneers to be carried out varies even during the same drying time. or,
The drying room temperature and the surrounding drying conditions are not constant, and the drying time (transport speed) of the following raw veneer determined based on the moisture content of the preceding dried veneer is the moisture content of the preceding veneer. If the initial moisture content of the following veneer is higher than the initial moisture content of the preceding veneer, the drying time may be insufficient and the veneer may be transported in a semi-dry state. Is high.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a transport speed is automatically corrected based on an initial moisture content, which is a moisture content of a raw veneer measured before being carried in, and dried before the finished moisture content is reached. A veneer veneer drying apparatus capable of continuously carrying out veneers, the configuration of which is at least a drying room temperature,
Based on the data of the water content of the raw veneer, the tree species and the thickness, the required drying time required to dry the raw veneer to a desired finish moisture content is calculated, and the calculated drying time corresponds to the calculated required drying time. The purpose is to automatically control the transport speed. The measurement of the water content is desirably performed in units of blocks divided for each predetermined length in the transport direction,
Also, at the time when the leading edge of the preceding block reaches the outlet, confirm that the block has been dried to the desired finish moisture content,
If the drying is inadequate, the conveyance is stopped or, if the preceding block has been dried, when the leading edge of the succeeding block reaches one block before the exit, the subsequent block The required remaining drying time required for the block to be processed is calculated, and the transport speed corresponding to the remaining required drying time can be automatically controlled.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A veneer veneer drying apparatus according to the present invention will be described with reference to the drawings. In FIG. 1 showing a drying apparatus, 1 is a transport path having a speed adjusting function, 2 is a drying chamber installed in the transport path, and a raw veneer 3a unwound from a roll 3 has a loading port A. From drying room to exit B
While passing through the veneer during drying that does not reach the final moisture content
b to a dried veneer 3c that satisfies the finish moisture content and is carried out. At the entrance A of the drying chamber 2, a high-frequency water content meter 4 of a roller type sensor is provided, and immediately before being loaded into the drying chamber 2,
The initial moisture content, which is the moisture content of a, is continuously measured, and the result is sent to the controller 5 as needed.
In addition, the unloaded dried veneer 3 is placed at the exit of the drying chamber 2.
c is provided with a finish moisture content meter 6 for measuring the finish moisture content, which is the moisture content of c.
To be sent out. Further, the temperature in the drying chamber is measured by a thermometer 7 installed in the drying chamber, and the result is sent to the controller 5.

Here, an example of controlling the transport speed by the controller will be described. Data such as tree species and thickness is input to the controller 5 in advance, and a boundary of the measurement range in the transport direction can be specified. When the apparatus is started, first, the raw veneer 3a is fed into the drying chamber at a standard speed. (See FIG. 1) The moisture content of the raw veneer 3a is continuously measured by the high-frequency moisture content meter 4 provided at the carry-in port when passing through the controller, and the controller 5 receiving the measurement result
Then, the average value of the initial moisture content is calculated for each block in the measurement range specified in advance. And for each individual block,
On the basis of the average value Wc of the initial moisture content, the temperature t1 in the drying chamber, the tree species coefficient a, and the thickness H1, for example, the drying time hd required for obtaining the final moisture content Ws using the following equation.
The transport speed is calculated so that the veneer 3b passes through the drying chamber over the drying time. hd = a (0.8Wc + 32.4-1.48 * Ws) *
(HI / H0) ＾ 1.26 / (t1 / t0) ＾ 1.15 Note that H0 is a reference single plate thickness and t0 is a reference temperature.

The first block b1 (hereinafter referred to as the first block) is transported at the determined transport speed, and the front edge of the first block b1 reaches one block before the outlet B. At the time (a in FIG. 2), it is checked whether or not the elapsed drying time has reached the required drying time.
If the elapsed drying time has reached or exceeded the required drying time, the transport speed is automatically controlled to the transport speed V2, and the transport is continued. Each of the transport speeds V1 and V2 is the length L of the drying chamber, the distance from the carry-out port to one block before is Lb, the temperature in the drying chamber is t1, the required drying time hd '. (Hd),
If the elapsed drying time is h1, it is calculated by the following equation. V1 = Lb * 60 * (t1 / t0) ＾ 1.15 / (hd
'-H1) V2 = L * 60 * (t1 / t0) ＾ 1.15 / hd It is confirmed whether or not drying has been performed to a desired moisture content. If drying is insufficient, the transport speed is controlled to be reduced or stopped. . Then, when the front edge of the first block b1 reaches the carry-out port (b in FIG. 2), it is checked whether or not the elapsed drying time has reached the required drying time. If the elapsed drying time exceeds the required drying time,
The process proceeds to a second block check described later. The stop time is calculated by, for example, the following formula, and after the stop, the discharge is performed at the speed of V2. hp = (hd−h1) * (t1 / t0) ＾ 1.15 In this way, for each block, the drying time determined to be optimal based on the moisture content of the green veneer before being carried into the drying chamber is calculated. And dried.

The veneer veneer drying apparatus of this embodiment measures the finish moisture content of the dried veneer immediately after being carried out by the finish moisture content meter 6 provided at the carry-out port B and sends it to the controller 5. In step 5, a function is added to check whether the finished moisture content of the dried veneer actually carried out is within the desired finished moisture content range, and to correct the transport speed. Therefore, even if a difference occurs between the calculated required drying time and the actually required drying time due to factors such as the initial moisture content of the raw veneer, the tree species and the thickness acting, the situation is adjusted. Control is realized.

When the leading edge of the first block b1 reaches the carry-out port, the front edge of the subsequent second block b2 is located one block before the carry-out port. Check remaining drying time.
Thereafter, the same control program as that of the first block is sequentially repeated for the third block b3, the fourth block, and so on.

[0010] By repeating these controls, the finish moisture content is checked by giving priority to the preceding block, so that the undried veneer is not carried out.

As described above, the veneer veneer drying apparatus of the present embodiment measures the water content for each block and feed-forward controls the transport speed based on the measured value. Even if veneers having different moisture contents are mixed in the veneer, the transport speed is accurately controlled to prevent the undried veneer from being carried out. Since the preceding block is divided into blocks and dried until the preceding block has an optimum moisture content, insufficient drying does not occur.

The formulas used in the embodiments are merely examples, and the formulas for calculating the transport speed are not limited to those in the embodiment.
The temperature and humidity of the outside air can be included in the requirement for calculating the transport speed.

Although the embodiment has described the continuous dryer for wound balls, the same applies to the roll dryer for small single plates.
It is not necessary to make the preceding and following blocks continuous.

[0014]

According to the present invention, it is necessary to dry the green veneer to a desired moisture content based on at least the temperature in the drying room and the moisture content, tree species and thickness data of the green veneer. Since a proper drying time is calculated, optimal control based on the veneer itself to be actually dried can be performed. or,
If the moisture content is measured for each block, it can be controlled with high accuracy. Furthermore, when the leading edge of the preceding block reaches the outlet, it is checked whether or not the drying has been completed to the desired finish moisture content. When the drying of the preceding block has been completed and the drying of the preceding block has been completed, when the leading edge of the succeeding block has reached one block before the exit, If the required remaining drying time required for the block to be processed is calculated and the transport speed is automatically controlled to correspond to the required remaining drying time, continuous control can be efficiently performed while simultaneously checking two consecutive blocks.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a veneer drying apparatus according to the present invention.

FIGS. 2A and 2B are explanatory diagrams showing a control example.

FIG. 3 is a flowchart of a control example.

[Explanation of symbols]

1. Conveyance path, 2. Drying room, 3. Rolled ball, 3a ...
Raw veneer, 3b ・ ・ Dry veneer, 3c ・ ・ Dried veneer,
4. High frequency water content meter, 5 Controller, 6, Finish moisture content meter, 7 Thermometer, A ... Carry-in, B ... Carry-out, b1, b2, b3 ... block.

Claims (4)

[Claims] 1. A required drying time required for drying a green veneer to a desired finish water content is calculated based on at least a drying room temperature and data on the water content, tree species and thickness of the raw veneer. And a veneer veneer drying apparatus that automatically controls the transport speed corresponding to the calculated required drying time. 2. The veneer veneer drying apparatus according to claim 1, wherein the measurement of the water content is performed in units of blocks divided by a predetermined length in the transport direction. 3. When the leading edge of the preceding block reaches the carry-out port, it is checked whether or not it has been dried to a desired finish moisture content. apparatus. 4. When the drying of the preceding block has been completed, when the leading edge of the following block reaches one block before the outlet, the remaining drying time required for the following block. Veneer veneer drying apparatus that automatically calculates the transport speed corresponding to the remaining required drying time.