JP3912385B2 - Wood drying equipment - Google Patents

Description

  The present invention relates to a wood drying apparatus capable of preventing the occurrence of defects such as deformation and cracking caused by artificial drying of wood and obtaining a uniform drying result.

  When processing wood into a product, it is necessary to dry the wood material so that the moisture content is not more than a predetermined value in order to prevent deformation and cracking due to shrinkage over time and to enhance dimensional stability. Therefore, as a standard example of artificially drying a material to be dried by a wood drying apparatus, the material to be dried is thermally softened at a high temperature by initial steaming at 95 ° C. for 8 hours in a drying chamber, A method is known in which a desiccant is dried for 72 hours under conditions of a dry bulb temperature of 120 ° C. and a wet bulb temperature of 90 ° C.

  Artificial drying under the above conditions involves drying the material to be dried according to a relatively long drying schedule, but due to differences in the tree species of the material to be dried and uneven atmosphere in the drying chamber, Cracks may occur on the surface or inside of the material, or the surface may darken, and it has been difficult to obtain a uniform and stable drying result.

  In addition, in the case of artificial drying in a drying room, in order to improve the productivity, the material to be dried is usually stacked and accommodated on a cart or the like so that a large amount of drying material can be obtained in one step. FIG. 8 is a diagram showing an outline of a basic configuration of a wood drying apparatus constructed for such a purpose. As shown in the figure, the floor surface of the drying chamber 1 which is kept airtight and heat-insulating is shown. The track rail 2 is installed, and the material to be dried H is carried in or out by the carriage 3 arranged on the track rail 2.

  The to-be-dried materials H are stacked on a carriage 3 with a pier 4 interposed therebetween, so that the atmosphere by controlled temperature and humidity is uniform while maintaining air permeability. A blower 6 for circulating air in the drying chamber 1 is disposed between the shielding plate 5 on the carriage 3 and the ceiling surface of the drying chamber 1 so as to be interposed in the air circulation path. A heating device (electric heater or steam heater) 7 is provided. Further, a humidifier (steamed pipe) 8 for injecting steam M serving as a humidification source is disposed in the air circulation path. When the temperature and humidity in the drying chamber 1 need to be adjusted, the air supply fan 9 and the exhaust fan 10 are driven to introduce outside air or exhaust the air in the drying chamber 1. In addition, the code | symbol 11 is a drain pipe for discharging | emitting excess water.

When the material to be dried is dried by the wood drying apparatus configured as described above, the steam M is diffused from the humidifying apparatus 8 and the air in the drying chamber 1 is circulated by the blower 6 to adjust the temperature and humidity. Create an atmosphere. And the drying schedule programmed according to conditions, such as a tree species, is set up, but a moisture content sensor is fixed to the material to be dried H selected in advance from the upper layer to the lower layer, and the moisture content detected thereby. Rate data is given to the control device so that drying control can be automated (for example, Patent Document 1).
JP 2002-86407 A

  In the conventional wood drying apparatus configured as described above, the steam M is dissipated from the humidifying device 8 in the air circulation path. In addition, it is necessary to vaporize quickly in the air circulation path so as to obtain an atmosphere of uniform temperature and humidity with respect to the material to be dried H from the upper layer to the lower layer stacked.

  However, when the air circulation path in the drying chamber 1 is unidirectional as shown by the arrows in FIG. 8, the mist-like steam M does not vaporize, but directly adheres to the material to be dried H as fine water droplets. May end up. When such a phenomenon occurs, the material to be dried H is stacked, so that the material to be dried H, which is higher than the lower layer, is easily exposed to the vapor M that is diffused, and the humidity difference occurs depending on the stacked parts. However, there will be a great difference in the drying results.

  If the drying operation is continued in the wood drying apparatus in such a state, a difference occurs in the drying conditions of the material to be dried H. Therefore, after the drying operation is finished, high moisture remains or deformation or cracking occurs. As a result, the yield is low and the productivity is low. And the temperature of the vapor | steam dissipated from a humidifier has a big temperature difference with 45-100 degreeC according to drying conditions, and it was very difficult to enable quick vaporization in any temperature range.

  The present invention has been made in view of such a conventional problem. The humidity is made constant in any part of the drying chamber in the wood drying apparatus, and a uniform drying result is obtained even when the materials to be dried are stacked. In order to increase the yield and improve the productivity, even with a thick material to be dried, there is no uniform dryness, deformation and cracking, In particular, an object of the present invention is to provide a wood drying apparatus from which a wood material suitable for the production of musical instruments can be obtained.

  Therefore, the present invention solves the above problems by means described below. That is, according to the first aspect of the present invention, the material to be dried is accommodated in a drying chamber that is kept airtight and heat-insulating, and the temperature and humidity in the drying chamber are adjusted by heating means, humidifying means, blowing means, and intake / exhaust means. A wood drying apparatus configured to dry the material to be dried in a dry atmosphere, wherein a humidifying unit is disposed at a lower portion of the drying chamber, and a blower unit is disposed on a ceiling surface of the upper portion of the drying chamber, and the humidifying unit is dried. At least one pair is provided in parallel with the opposite side surfaces of the chamber so that the blowing direction by the blowing means is reversed at regular time intervals, and only one of the humidifying means is operated by switching in synchronization with this turning. .

  In the invention described in claim 2, the atmosphere in which the material to be dried is accommodated in a drying chamber in which airtightness and heat insulation are maintained and the temperature and humidity in the drying chamber are adjusted by a heating means, a humidifying means, a blowing means and an intake / exhaust means. In the wood drying apparatus for drying the material to be dried, a humidifying means for spraying water is disposed at the lower part of the drying chamber, and a blower means is disposed on the ceiling surface at the upper part of the drying chamber. The humidifying means is provided in at least a pair parallel to the opposing side wall surfaces of the drying chamber so that the air blowing direction by the air blowing means is reversed at a constant time interval, and only any one of the humidifying means is switched by synchronizing with the reversal. To work.

  According to the present invention, the air blowing direction by the air blowing means in the drying chamber is reversed at regular intervals, and only one of the humidifying means is operated by switching in synchronization with this reversal. In the case of the above, the humidity is constant, and even when the materials to be dried are stacked, a uniform drying result is obtained, so that the yield is high and the productivity can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated to the structure same as the past.

  FIG. 1 shows a wood drying apparatus embodying the present invention. The drying chamber 1 is kept airtight and heat-insulating, but an open / close door is provided in one or both of the front and rear directions in the drawing. The to-be-dried material H is carried in from the outside or carried out to the outside by the carriage 3 which is arranged on the track rail 2 installed on the floor surface.

  The to-be-dried materials H are stacked on the carriage 3 with the piers 4 interposed therebetween, and maintain the air permeability between the to-be-dried materials H as in the prior art, and the atmosphere by the adjusted temperature and humidity becomes uniform. Like that. A blower 6 for circulating the air in the drying chamber 1 is disposed between the shielding plate 5 on the carriage 3 and the ceiling surface of the drying chamber 1, and a heating device (electrical device) is interposed in the air circulation path. A heater or steam heater) 7 is provided. In addition, the said air blower 6 in this invention employ | adopts what was comprised so that an airflow may generate | occur | produce forward when a fan is rotated forward, and an airflow will generate | occur | produce backward when it reverse | rotates.

  A pair or a plurality of pairs of water supply pipes 12 and 13 facing each other with the carriage 3 interposed therebetween are arranged in parallel with the side wall surface on the floor surface at the bottom of the drying chamber 1, and the water supply pipes 12 and 13 are controlled by the control device 16. Connected to the pumps 14 and 15. The control device 16 controls the amount and timing of water W sprayed from the water supply pipes 12 and 13, and controls forward / reverse rotation of the blower 6 and heat generation control of the heating device 7. The pumps 14 and 15 may be replaced with electromagnetic valves, and hydrostatic pressure may be used. Moreover, the water W sprinkled from the water supply pipes 12 and 13 appropriately adopts water that meets the drying conditions, such as normal temperature water or heated water heated to an arbitrary temperature. Furthermore, the water spray direction of the water W from the water supply pipes 12 and 13 is preferably inwardly directed to the floor surface or outwardly directed to the wall surface so that water droplets can be actively prevented from scattering to the material to be dried H.

  Next, an embodiment when the wood drying apparatus of the present invention configured as described above is operated will be described below. In FIG. 2, the blower 6 is rotated forward so that the air in the drying chamber 1 is circulated as indicated by the arrow in the figure, and the heating device 7 in the air circulation path is controlled in heat generation by the control device 16 and circulated. The air to be heated is heated to a predetermined high temperature. At this time, the pump 14 is driven by an instruction from the control device 16 and sprinkles water W of a predetermined amount of water discharged from the water supply pipe 12, but the drive of the pump 15 is stopped by an instruction from the control device 16. Therefore, there is no sprinkling of the water W from the water supply pipe 13.

  When the operation is started in this manner, the water supply pipe 12 is in a state of receiving the airflow flowing down from the ceiling surface of the drying chamber 1 on the floor surface, so that the water W that has been sprinkled is diffused toward the floor surface by the force of the airflow. In addition, water droplets do not scatter to the material to be dried H. The water W sprinkled from the water supply pipe 12 by the air heated to high temperature by the heating device 7 is vaporized and stirred with the circulating air to increase the humidity, so that a constant humidity is maintained at any part in the drying chamber 1. Will be drunk.

  FIG. 3 shows a state in which the blower 6 is reversed based on an instruction from the control device 16 and the air in the drying chamber 1 is circulated as shown by an arrow in the figure. As in the case shown in FIG. The heating device 7 in the circulation path is controlled in heat generation by the control device 16, and the circulating air is heated to a predetermined high temperature. At this time, the pump 15 is driven by an instruction from the control device 16 and sprinkles water W of a predetermined amount of water discharged from the water supply pipe 13, but the drive of the pump 14 is stopped by an instruction from the control device 16. Therefore, there is no sprinkling of the water W from the water supply pipe 12.

  As described above, according to the above embodiment, the water W is sprinkled from the water supply pipe on the windward side of the air circulation path on the floor surface of the drying chamber 1, and the water spraying of the water W from the water supply pipe on the leeward side is stopped. Thereby, scattering of the water W to the to-be-dried material H on the trolley | bogie 3 can be prevented completely. Moreover, since water is used regardless of steam in the present invention, the humidity can be increased without increasing the temperature, and a uniform drying result can be obtained from the upper layer to the lower layer of the material to be dried H. .

  Furthermore, in the present invention, in order to make the temperature and humidity in the drying chamber 1 more constant, the direction of air circulation can be switched at regular time intervals, and the direction of the air circulation is synchronized. Then, the water W was sprinkled from either one of the water supply pipes 12 and 13. That is, as shown in FIG. 4 as an example, during the high level period (H) of the control signal, the blower 6 is rotated forward and the pump 14 is driven to sprinkle the water W from the water supply pipe 12 and the low level of the same signal. During the period (L), the blower 6 is reversed and the pump 15 is driven to sprinkle the water W from the water supply pipe 13, but the operation schedule can be performed continuously or intermittently, such as the tree species of the material to be dried, etc. It is executed together with temperature control by a program set in advance based on conditions. By controlling in this way, the air in the drying chamber 1 can be sufficiently stirred, and the temperature and humidity can be made more constant at any part.

  5 and 6 show another example of the embodiment of the present invention. As shown in FIG. 5, when the blower 6 is rotating forward, the water W is sprinkled from the water supply pipe 13 so that the blower 6 In the case of reverse rotation, water W is sprinkled from the water supply pipe 12 as shown in FIG. When operated in this way, the air circulating under the carriage 3 rises in the form of an air curtain, and the water W from the water supply pipes 12 and 13 is sprinkled in the direction of the wall surface of the drying chamber 1 and is covered. Water droplets are not scattered on the drying material H.

  In the above case, when controlling the air circulation direction and the timing of water spraying from the water pipes 12 and 13, as shown in FIG. 7, the blower 6 is rotated forward and the pump 15 is turned on at a high level (H) of the control signal. The water W is driven and sprinkled from the water feed pipe 13, and the blower 6 is reversed and the pump 14 is driven to sprinkle the water W from the water feed pipe 12 during the low level period (L) of the same signal. .

  According to an example of the result of repeating the experiment using the wood drying apparatus of the present invention, a square material (cross section 40 mm square and 80 mm square) of rosewood (specific gravity 1.0) as a material to be dried, dry bulb temperature 45 ° C., wet bulb temperature When drying begins at an initial humidity of 86% at 42 ° C and gradually decreases the humidity within a period of 68 days, the final dry bulb temperature is 65 ° C, the wet bulb temperature is 40 ° C and the humidity is 29.5%. As a result, the initial moisture content of the material to be dried was 14%, which was finally 8%, and it was possible to make the material optimal for musical instruments without deformation or cracks.

It is a figure explaining the structure of the wood drying apparatus of this invention. It is a figure of the 1st process explaining the operation mode of the wood drying device of the present invention. It is a figure of the 2nd process explaining the operation | movement aspect of the timber drying apparatus of this invention. It is a figure explaining the example of the operation | movement timing of the wood drying apparatus of this invention. It is a figure of the 1st process explaining other embodiments of the present invention. It is a figure of the 2nd process explaining other embodiments of the present invention. It is a figure explaining the example of the operation | movement timing of other embodiment of this invention. It is a figure explaining the structure of the conventional wood drying apparatus.

Explanation of symbols

1 .... Drying room 2 .... Track rail 3 .... Dolly 4 .... Picking ... 5 ... Shielding plate 6 .... ··· Blower 7 ··· Heating device 12 · 13 · Water supply pipe 14 · 15 · · · Pump 16 · · · Control device H · · · Covered Drying material W ... water

Claims (2)

The material to be dried is accommodated in a drying chamber that is kept airtight and insulated.
A wood drying apparatus configured to dry the material to be dried in an atmosphere in which the temperature and humidity in the drying chamber are adjusted by a heating unit, a humidifying unit, a blowing unit, and an intake / exhaust unit,
While disposing the humidifying means at the lower part of the drying chamber, disposing the blowing means on the ceiling surface of the upper part of the drying chamber,
At least a pair of humidifying means is provided in parallel to the opposing side wall surfaces of the drying chamber, so that the blowing direction by the blowing means is reversed at regular time intervals,
Furthermore, only one of the humidifying means is operated by switching in synchronization with this inversion,
A wood drying device characterized by. The material to be dried is accommodated in a drying chamber that is kept airtight and insulated.
A wood drying apparatus configured to dry the material to be dried in an atmosphere in which the temperature and humidity in the drying chamber are adjusted by a heating unit, a humidifying unit, a blowing unit, and an intake / exhaust unit,
While disposing the humidifying means to sprinkle water in the lower part of the drying chamber, disposing the blowing means on the ceiling surface of the upper part of the drying chamber,
At least a pair of humidifying means is provided in parallel to the opposing side wall surfaces of the drying chamber, so that the blowing direction by the blowing means is reversed at regular time intervals,
Furthermore, only one of the humidifying means is operated by switching in synchronization with this inversion,
A wood drying device characterized by.

Images