JPH0798177A - Lumber drying device - Google Patents

Abstract

PURPOSE:To enable reliable drying control to be carried out without having any warping or cracking in lumber by a method wherein a heating pipe, a cold water atomizing pipe, a steam injecting pipe and a suction or discharging duct are controlled in such a manner that the temperature and humidity within each of drying chambers are independently maintained within a desired range. CONSTITUTION:A damper arranged in a suction discharging duct 7 during a drying step is automatically opened or closed in such a way that the temperature and the humidity set under a program control are maintained. A heating pipe 5, a cold water atomizing pipe 6 and a steam injection pipe 9 are so operated that their set values under a program control are maintained. The temperature and humidity within a drying chamber are detected by a temperature sensor 8a and a humidity sensor 8b within each of drying chambers 1A and 1B, their present values are transmitted to a control panel for performing a program control. The control panel transmits control values to the dampers for the heating pipe 5, the cold water atomizing pipe 6, a steam injection pipe 9 and a suction or discharging duct 7 and controls them. With such an arrangement as above, it is possible to perform reliable drying control without having no warping or cracking in the lumber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus used for drying wood made of natural wood.

[0002]

2. Description of the Related Art Heretofore, as a drying apparatus of this type, only a ventilation fan for circulating drying air and an air heater, or only a ventilation fan for circulation and an air dehumidifier are provided in a drying chamber. It is also known to add a steam humidifier to them. Further, there is known a device equipped with a device for spraying squeezed cold water in a spray state by sensor control. (Japanese Unexamined Patent Publication No. 2-192584) Incidentally, in the case where the capacity of the drying process is large, several independent drying chambers are installed or the drying chambers are extended in the longitudinal direction.

[0003]

In the conventional drying device, when the processing capacity is insufficient in only one chamber of the drying device,
Either the length of the drying chamber was extended, or each drying chamber was partitioned by partition walls to provide several independent drying chambers. Further, in order to cope with the shortage of the processing capacity, a method of widening the width of the drying chamber to increase the volume of the drying chamber can be considered. The dried wood to be stored in the drying chamber is generally arranged in a cross girder so that the drying air is in contact with the drying air evenly, but the wide frontage In this case, the ventilation resistance of the dried wood increases in the ventilation direction, and it is not practical because sufficient ventilation is not achieved and drying unevenness remarkably occurs. Furthermore, in the case of extending the length of the drying chamber, there is a problem in that not only the time for loading and unloading the dried wood from the drying chamber inlet is significantly increased, but also it is difficult to accommodate the installation space of the drying device. . In addition, when each drying chamber is partitioned by a partition and several drying units of independent shape are installed side by side, the construction cost of the drying chamber becomes extremely large, and the construction period becomes long. Furthermore,
In the above conventional apparatus, not only the drying temperature but also the drying humidity is controlled only by the steam. There is a problem in that the amount of heat required is applied, resulting in heating and humidification. In the process of cooling the dried wood at the end of drying, it is necessary to rely on the introduction of a large amount of outside air, and because the humidity control necessary for cooling the dried wood cannot be performed, the dried wood is exposed to the outside with low humidity. ,
The wood was warped and cracked. As an attempt to solve these problems, there is a device equipped with a device that sprays squeezed cold water in a spray form by sensor control, but spraying cold water is only in the cooling process at the end of drying, Since the humidification was performed by the injection of steam, the humidification had a humidifying and heating effect as described above, which made it difficult to control the temperature of the drying chamber. The present invention is
In view of the above problems in the conventional technology, the construction cost and construction period are not increased unnecessarily, the installation space of the device is easily accommodated, and the wood is not warped or cracked. It is an object of the present invention to provide a wood drying device capable of reliable drying control.

[0004]

The wood drying apparatus of the present invention which has achieved the above object has a drying chamber having at least two drying chambers partitioned by substantially any number of columns, and each drying chamber. A blower capable of reversing the blowing direction provided for each, a pair of heating pipes, cold water spray pipes, steam injection pipes, intake and exhaust ducts provided on both sides of each blower, and optional side walls and partition columns for the drying chamber. Several air guides are provided so that the drying air from each blower circulates independently in each dryer.
The wind direction plate that can be reversed according to the blowing direction, the temperature sensor and humidity sensor attached to each drying chamber, and the temperature and humidity inside each drying chamber obtained from the temperature sensor and humidity sensor are compared with the set value. The heating pipe, the cold water spray pipe, the steam injection pipe, and the intake and exhaust ducts are controlled, and the temperature and humidity in each drying chamber are independently maintained in a desired range. . In addition, in response to a signal from the control means, the blower direction of the blower is reversed at regular time intervals, and the tilt angle of the wind direction plate that has become improper due to the reversal of the blower direction is automatically adjusted to the proper direction in conjunction with the reversal of the blower. It may be adjusted to. Furthermore, when the temperature inside each drying chamber is low near the upper limit of the set value and the humidity is low, the cold water spray pipe operates, and when the temperature is near the lower limit of the set value and the humidity is low, the steam injection pipe operates and To regulate the humidity of
Preferably the control means is programmed.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of a front side of a drying device according to the present invention, FIG. 2 is a cross-sectional view of a side surface, FIG. 3 is a perspective view of the whole,
FIG. 4 is a flow sheet diagram for programmatically controlling the temperature / humidity, the blowing and the drying time of FIG.

As shown in FIG. 1, a substantially arbitrary number of columns 2 are provided at the center of the drying device 1 along the longitudinal direction of the drying chamber so as to divide the drying chamber into two. At least one circulation fan 3 is preferably provided at the center of the upper part of each of the drying chambers 1A and 1B of the divided drying chambers so that the air flow can be forward or reverse in the direction of the wind direction 4 along the longitudinal direction of the drying chambers. There are 5 to 6 heating pipes 5 for heating the circulating air before and after the circulation blower 3 in the blowing direction.
A pair of cold water spray pipe 6 and steam injection pipe 9 for humidifying the circulating air are provided. As a result, the drying air blown by the circulation blower 3 is heated to a required temperature by passing through the heating pipe 5 and is further humidified to an appropriate humidity by the cold water spray pipe 6 or the steam injection pipe 9. Are sent to the drying room. Reference numeral 7 is an intake / exhaust duct for exhausting the dry indoor air that has become humid during the drying process and introducing low temperature and low humidity outside air into the drying chamber. At the beginning of drying, a large amount of water is discharged from the wood 11 to be dried, so that the circulating air in the drying chamber needs a large amount of dehumidification. A damper 16 is provided in the intake / exhaust duct 7, and the damper 16 is automatically opened in order to exhaust the humid circulating air at the beginning of drying and suck the low-humidity outside air. In the subsequent drying process, the damper 16 is designed so as to automatically open and close so as to maintain the humidity and temperature set by the program control, and further, the heating pipe 5, the cold water spray pipe 6, and the steam injection pipe. 9 also operates so as to maintain the set value under program control. The temperature and humidity in the drying chamber are detected by the temperature sensor 8a and the humidity sensor 8b provided in each drying chamber, and the control panel 12 (FIG. 4) for performing the program control.
The control panel 12 transmits the control value to the heating pipe 5, the cold water spray pipe 6, the steam injection pipe 9, and the damper 16 of the intake / exhaust duct 7 for control.

The wind direction plates 10 are arranged on the left and right wall surfaces in the drying chamber and on the pillar 2 in the center of the drying chamber, and are blown by the circulation blower 3, heated by the heating pipe 5, and further cooled water spray pipe 6 and steam injection pipe. The circulating air for drying whose humidity is controlled through 9 is evenly ventilated between the dried woods 11, and at the same time, the arrangement and inclination angle are set so that the circulating air does not interfere with the circulating air of the adjacent drying chamber. It is devised and constitutes a substantial partition with the adjacent drying chamber. In the case of the method of reversing the blowing direction 4 at regular time intervals by changing the rotation direction of the circulation blower 3, the driving device 17 connected to the wind direction plate 10 causes the wind direction to have an inclination angle suitable for the reversed wind direction 4. The board 10 is automatically adjusted. In the case where the number of drying chambers exceeds two, the one or several chambers sandwiched between the drying chambers on the right and left ends are connected to the adjacent chambers on the left and right only by the columns 2 on which the wind vanes 10 are arranged. It will be separated.

As shown in the flow sheet diagram of FIG. 4, the cold water spray pipe 6 is communicated with the cold water pressing device 13 via a cold water spraying solenoid valve 18, and the solenoid valve 18 is opened and closed by a signal from the control panel 12. And spray cold water. The steam injection pipe 9 is connected to the steam boiler 14 via a steam injection electromagnetic valve 19, and the electromagnetic valve 19 is opened and closed by a signal from the control panel 12 to inject steam. The heating pipe 5 is a solenoid valve 20 for heating steam.
Is communicated with the steam boiler 14 via the control panel 1
The electromagnetic valve 20 is opened / closed by a signal from 2 to control the air supply of steam into the heating pipe to indirectly heat the dry room air. The damper 16 provided in the intake / exhaust duct 7 for ventilation of the circulating air in the dry room is connected to the damper driving machine 15, and opens / closes the damper according to a signal from the control panel 12. The blower 3 is configured to stop the operation and to rotate forward and backward in response to a signal from the control panel 12, and in conjunction with this, the wind direction plate 10 connected to the wind direction plate driving device 17 forms an appropriate inclination angle. Has been The temperature sensor 8a and the humidity sensor 8b arranged in the drying chamber are adapted to transmit the current value in the drying chamber to the control panel 12.

As an example of concrete program control, it is generally said that artificial drying of wood is generally the most difficult.
The drying process of the cedar-bearing pillar material for construction without splitting the back will be described. Artificial drying of wood is faster when the heating temperature is higher and the relative humidity is lower. However, since many cracks and irregularities occur, the temperature and humidity conditions from the initial stage of drying to the end of drying are roughly determined depending on the type of wood to be dried, the standard cross-sectional dimension, and the moisture content state at the time of starting drying. For example,
3m long, width and thickness of 10.5
The set values of the temperature and the relative humidity in the drying chamber from the initial stage of drying to the end when artificial drying is performed by the drying apparatus of the present invention immediately after lumbering to a square cm are as follows.
Incidentally, the water content of each of the dried woods in the initial stage of drying is about 100% to 150%. At the initial stage of drying, the time required to rise from room temperature to 70 ° C. is about 8 hours, and the relative humidity during this period is maintained at 95%. Next, maintain the drying room temperature at 70 ° C and relative humidity 91% for 20 hours. Furthermore, the room temperature is 70 ° C and the relative humidity is 87%, which is maintained for 24 hours. Maintains room temperature of 70 ° C and relative humidity of 83% for 56 hours. Maintains room temperature of 75 ° C and relative humidity of 84% for 72 hours. Maintains a room temperature of 75 ° C and a relative humidity of 80% for 96 hours. From here, the cooling process in the drying chamber is started. While maintaining the relative humidity in the room at 79%, the room temperature is lowered to 35 ° C. in a required time of about 10 hours. Then, when the temperature of the material center of the dried wood changes from 35 ° C. to 40 ° C., the dried wood is unloaded from the drying device.

[0010]

Next, the operation of this embodiment will be described. First,
The wood 11 to be dried is carried in through the wood carry-in / carry-out port provided on the entire surface or the rear surface of the rectangular parallelepiped closed type drying chamber 1. After the wood 11 is carried in, the carry-in entrance is closed by a door having a good airtightness. Next, when the fully automatic switch of the control panel 12 is turned on, the drying device is fully automatically dried within a set drying time while controlling the temperature and humidity in a process suitable for the material type of the dried wood 11 by program control. Wood 11
Operate to dry. At the beginning of drying, a large amount of water is released inside the wood, so the damper 16 of the intake and exhaust duct 7
Is opened to the extent that it does not lower the indoor temperature and operates so as to exhaust the humid air in the drying room and at the same time introduce fresh outside air with low humidity. At the beginning and during the drying, the circulating air in the drying chamber is heated by the heating pipe 5,
In addition, when the current temperature is high and humidification is required with respect to the temperature setting value in the drying chamber by program control,
Although it is humidified by the spray of cold water from the cold water spray pipe 6,
When the current temperature is low and humidification is required, humidification is performed by steam injection from the steam injection pipe 9. At the time of dehumidification, the indoor humidity is lowered by the air supply / exhaust action of the intake / exhaust duct 7 as described above. The circulating air in the drying chamber is designed to reverse the blowing direction 4 by changing the rotation direction of the circulating blower 3 at regular intervals by program control, and in conjunction with this, the driving device 17 connected to the wind direction plate 10 Thus, the wind direction plate 10 is automatically adjusted to a tilt angle suitable for the reversed wind direction 4.

[0011]

As described above, according to the present invention, the cold water spray pipe 6 is used.
By arranging, it is possible to blow a low enthalpy by cold water spray into the drying chamber, instead of a high enthalpy such as humidification with only steam, even in the process of cooling the room temperature such as at the end of drying. The necessary amount of humidification can be performed without raising the temperature of the drying chamber. In the drying of wood, it is necessary to perform drying treatment in consideration of the equilibrium water content of wood (the water content when the water content of wood is in equilibrium and no longer changes at a certain temperature and humidity). By disposing the spray pipe 6, it is possible to easily finish the drying of the wood in the drying chamber so that the equilibrium moisture content of the wood in the outside air becomes the same, so that the wood which has been dried is immediately used for construction and the like. Even if you use
No warpage or cracking occurs. Further, as soon as the drying is finished, the equilibrium moisture content in the open air can be made equal to that of the outside air, so that the drying temperature in the drying process can be made higher than before, and the number of days required for drying can be greatly shortened. It is a thing. Furthermore, in the case of multiple drying chambers, by eliminating the partition that separates each drying chamber and using only the columns with the wind direction plate installed, it is possible to significantly reduce not only the construction period of the drying device but also the construction cost. It is possible. By providing the wind direction plate not only on the pillar of the partition of the drying chamber but also on the left and right wall surfaces in the drying chamber, the drying air circulating in the drying chamber does not interfere with the circulating air in the adjacent chamber and is independent. Effectively circulates in each drying chamber,
It functions as if each drying chamber were separated by a partition.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a drying device according to the present invention in a front view.

FIG. 2 is a side sectional view.

FIG. 3 is an overall perspective view

FIG. 4 is a flow sheet diagram for programmatically controlling the temperature / humidity, air blowing, and drying time settings of FIG. 1.

[Explanation of symbols]

 1 Drying Device 2 Pillar 3 Circulation Blower 4 Wind Direction 5 Heating Pipe 6 Cold Water Spray Pipe 7 Intake and Exhaust Duct 8a Temperature Sensor 8b Humidity Sensor 9 Steam Injection Pipe 10 Wind Direction Plate 11 Dry Wood 12 Control Panel 13 Cold Water Compressor 14 Steam Boiler 15 Suction Exhaust duct damper drive 16 Intake and exhaust duct damper 17 Wind vane drive 18 Cold water spray solenoid valve 19 Steam injection solenoid valve 20 Heating steam solenoid valve 1A Dryer 1B Dryer

Claims (3)

[Claims] 1. A drying chamber having at least two drying chambers partitioned by substantially any number of columns, a blower capable of reversing the blowing direction provided for each drying chamber, and both sides of each blower. Arbitrary numbers are provided on the pair of heating pipes, cold water spray pipes, steam injection pipes, intake and exhaust ducts, and both side walls of the drying chamber and partition columns, and the drying air from each fan blows through each drying chamber. An independent air guide that circulates according to the direction of air flow, a temperature sensor and humidity sensor attached to each drying chamber, and inside each drying chamber obtained from the temperature sensor and humidity sensor. Means for controlling the heating pipe, the cold water spray pipe, the steam injection pipe, and the intake / exhaust duct by comparing the temperature and humidity of each of the above with the set value, and independently maintaining the temperature and humidity in each drying chamber within a desired range. And a wood drying device. 2. The signal from the control means reverses the blowing direction of the blower at regular time intervals, and the tilt angle of the wind direction plate, which has become improper due to the reversing of the blowing direction, is interlocked with the reversing of the blower to obtain the proper direction. 2. The wood drying apparatus according to claim 1, wherein the wood drying apparatus is automatically adjusted. 3. When the temperature in each drying chamber is near the upper limit of the set value and the humidity is low, the cold water spray pipe operates, and when the temperature is near the lower limit of the set value and the humidity is low, the steam injection pipe operates. 2. The wood drying apparatus according to claim 1, wherein the control means is programmed to control the humidity in the drying chamber.