JPH035508B2 - - Google Patents

Description

Detailed Description of the Invention (a) Technical Field The present invention relates to a grain dryer that dehumidifies and dries grain using dehumidified dry air.

(b) Prior Art In general, low-temperature drying does not cause shell cracking of grains and enables high-quality drying with improved taste. Dehumidifying grain dryers are in practical use to perform such low-temperature drying. In conventional dehumidifying and drying type grain dryers, dehumidified air is either directly introduced into the drying chamber, or after being dehumidified, the air is heated with a heater or the like and then introduced into the drying chamber. however,
Since the temperature of dehumidified air largely depends on the temperature and humidity of the outside air, it is difficult to optimally control constant temperature drying with a drying method in which dehumidified air is directly introduced into a drying chamber. In addition, in the case of a method in which dehumidified air is heated, a heating device such as a heater is provided in the dryer body, which increases the size of the dryer, leading to an increase in price. Furthermore, in low-temperature drying, it is necessary to exhaust dry air and hot air, so there is a problem that the structure of the dehumidifying section becomes large.

(c) Purpose of the Invention In view of the above-mentioned circumstances, the purpose of the present invention is to provide a grain dryer that has a simple structure, is inexpensive, can control the temperature of dehumidified air with high precision, and is capable of optimal constant temperature drying. It's about doing.

(d) Structure of the Invention The present invention provides a dehumidifying drying type grain dryer, which includes: an air passage leading from the atmosphere to the ventilation hole; and a regeneration exhaust passage that is attached to the air passage and has one end communicating with an exhaust port of the air passage. A plurality of ventilation passages are formed in the radial direction by the moisture-absorbing material installed on the side surface of the cylinder.
a rotating drum arranged such that the ventilation passages are included in both the air blowing passage and the regeneration exhaust air passage; a drum driving device that rotates the rotating drum; a heat source disposed in the regeneration exhaust air passage; The present invention is characterized in that it includes a blower that guides outside air to the air passage and also guides hot air to the regeneration exhaust passage.

(e) Embodiment FIG. 1 is a schematic structural diagram of the main structure of the drying section of a grain dryer according to an embodiment of the present invention, and FIGS. 2 and 3 are schematic structural diagrams of the dehumidifying section of the same grain dryer. be.

The grains 2 loaded in the storage tank 1 are stored in a drying room 7,
8, circulation is carried out from the storage tank 1 to the drying chambers 7 and 8 by the rotary valves 4 and 5 provided below, the screw conveyor 6, and the circulation device 3 such as a bucket elevator provided outside the storage tank 1. It is conveyed to the storage tank 1 again through the passage 9. The circulation passage 9 is provided from the outlet of the screw conveyor 6 to the upper part of the storage tank 1 via the circulation device 3.
The drying chambers 7 and 8 also serve as circulation paths for the grains 2, and are equipped with a net or the like having a mesh size that does not allow the grains 2 to penetrate inside and outside, and have a large number of ventilation holes. The ventilation holes on the inside of the drying chambers 7 and 8 face the side surface of a rotating drum 13, which will be described later, and the ventilation holes on the outside communicate with air passages 10 and 11, respectively.
A regeneration exhaust passage 14 is located slightly below the ventilation passages 10 and 11.
is attached. The suction side of the regeneration exhaust path 14 faces the side surface of the rotating drum 13, and a flow rate regulating shutter 15 is attached to one end thereof. Further, the regeneration exhaust path 14 communicates with the exhaust side of the air blowing paths 10 and 11 through the shutter 15. Air duct 1
0 and 11 both communicate with the outside air through the exhaust port 16. A blower 17 that guides outside air and hot air to the exhaust port 16 is provided near the exhaust port 16 .

The rotating drum 13 is provided so as to be located between the air blowing passages 10 and 11 and the regeneration exhaust passage 14. As shown in FIG. 4, the rotating drum 13 has an opening 13a formed in one end surface, and a moisture absorbing material 13b is housed in the cylindrical side surface thereof. The moisture-absorbing material 13b is a corrugated substrate of paper or polyester coated with a moisture-absorbing agent such as lithium chloride, or a non-woven fabric impregnated with such a moisture-absorbing agent and processed into a honeycomb structure. The moisture absorbing material 13b is attached to the side surface of the rotary drum 13 so that a cavity formed by a corrugated substrate or a nonwoven fabric faces in the radial direction of the rotary drum 13, and the cavity forms a ventilation path of the rotary drum 13. The rotating drum 13 is rotatably mounted inside the dryer so that the opening 13a faces the air intake port 18 of the dryer main body. Of the total area of the opening 13a, 3/4 of the area is indicated by the symbol A in FIG.
4 faces the hot air port 19a of the regeneration heater 19. Further, the rotating drum 13 receives a driving force from a motor 21 via a transmission belt 20 stretched around a rotating shaft and rotates.

As mentioned above, the rotating drum 13 is
1 and the regeneration exhaust passage 14, the ventilation passage on the side surface is connected to the ventilation passage 1 as the rotary drum 13 rotates.
0, 11 and the regeneration exhaust path 14 in sequence. In this way, the air passages 10, 1
1. By arranging the regeneration exhaust path 14 and the rotating drum 13, when the blower 17 is operated, outside air is sucked in through the air intake port 18, and the hollow part of the rotating drum 13 and the ventilation path are filled as shown by arrow a. The air then passes through drying chambers 7 and 8, and is further discharged from an exhaust port 16 through air passages 10 and 11 as shown by arrow b. On the other hand, the hot air generated by the heater 19 is guided to the regeneration exhaust path 14 through the hollow part of the rotary drum 13 and the ventilation path, and is further discharged through the exhaust port 16 as shown by arrow c. In addition, the storage tank 1 is equipped with a moisture meter 12 for measuring the moisture content of grains.
is attached to the outside wall of the dryer body, and an outside air temperature sensor 32 and an outside air humidity sensor 33, which will be described later, are attached to the outside wall of the dryer body to measure outside air temperature and outside air humidity, respectively, and obtain parameters for performing low temperature control. That's what I do.

FIG. 5 is a control block diagram of this grain dryer.

The control unit 27 is composed of a microcomputer, and controls low-temperature drying until the moisture content of the grain reaches the stop moisture content. The outputs of the moisture meter 12, the outside air temperature sensor 32, and the outside air humidity sensor 33 are led to the controller 27 as input parameters to the controller 27. The stop moisture content setter 30 includes a setting volume for setting a desired stop moisture content, which is arranged on a control panel (not shown), and the setting value is set by the control unit 27.
guided by. The control unit 27 follows a pre-stored low-temperature drying program and controls the measured moisture content,
Based on each input parameter of stop moisture content, outside air temperature, and outside air humidity, a control signal is output to the rotation speed control circuit 28 and the heater temperature control circuit 29 so that the temperature of the dehumidified air becomes an optimum value. Rotation speed control circuit 2
8 controls the rotation speed of the drum rotation motor 21 according to instructions from the control section 27. The heater temperature control circuit 29 controls the current supplied to the regeneration heater 19 according to instructions from the control section 27 .

Further, a shutter opening/closing device 31 is connected to the control section 27, and the shutter opening/closing device 31 is connected to the shutter 15.
Adjust the opening. The shutter 15 is the hot air supply path 1
4 is set at an opening position where a predetermined hot air is supplied.

In the grain dryer configured as above,
When the blower 17 is operated, the air intake port 18 is in communication with the air passages 10 and 11 via the air passage of the rotary drum 13 and the drying chambers 7 and 8, so that outside air is sucked in through the air intake port 18. The outside air taken in enters the hollow part of the rotating drum 13 through the opening 13a and passes through the ventilation path of the rotating drum 13. When the outside air passes through the ventilation path of the rotating drum 13, the moisture absorbing material 13
It is dehumidified and dried by the moisture absorbent b. The air thus dried is supplied to the drying chambers 7 and 8, and passes through the drying chambers 7 and 8, thereby drying the grains in the drying chambers 7 and 8. The air that has passed through the drying chambers 7 and 8 is discharged from the exhaust port 16 through the air passages 10 and 11 as shown by the arrow d. On the other hand, current is supplied to the regeneration heater 19 simultaneously with the operation of the blower 17. The hot air port 19a of the heat source section provided with the heater 19 is in communication with the regeneration exhaust path 14 through a part of the ventilation path of the rotating drum 13, so that the hot air is directed toward the heater 19 by the operation of the blower 17. It is guided into the hollow part of the rotating drum 13 through the opening 13a, and passes through the ventilation path of the rotating drum 13 (the ventilation path located in the area B). The ventilation path on the side facing the regeneration exhaust path 14 receives hot air generated by the heater 19 and releases absorbed moisture. The moisture absorbent 13b is regenerated by releasing absorbed moisture and generates latent heat during regeneration. The latent heat thus generated is used to warm the dry air supplied to the drying chambers 7 and 8. The hot air that has passed through the ventilation path is guided to the exhaust port 16 through the regeneration exhaust path 14 and discharged together with the moisture released by the regeneration.

As described above, due to the rotation of the rotating drum 13, the air passages alternately move between the air blowing passages 10 and 11 and the regeneration exhaust passage 14, whereby the outside air absorbs moisture and is warmed by latent heat. Therefore, low-temperature drying can be performed using appropriately heated dry air. When the temperature or humidity of the outside air changes, the temperature of the dry air can be controlled by appropriately changing the number of rotations of the rotary drum 13 or the temperature of the hot air generated by the regeneration heater 19. If it is desired to raise the temperature of the dry air, the latent heat generated by regeneration can be increased by increasing the number of cycles of moisture absorption and regeneration per unit time, thereby raising the temperature of the dry air.
Further, by increasing the current supplied to the regeneration heater 19, the regeneration speed of the moisture absorbent material can be increased, thereby increasing the temperature of the dry air.

As mentioned above, the rotating drum 13 acts as a latent heat exchanger by moving the air passages of the rotating drum 13 alternately between the air blowing passages 10 and 11 and the regeneration exhaust passage 14, thereby controlling the temperature of the dehumidified air with high precision. It can be carried out. Therefore, even if the temperature and humidity of the outside air change, optimal low-temperature drying can be performed by controlling the rotation speed of the rotary drum 13 and the temperature of the hot air for regeneration. In addition, the air blowing paths 10 and 11 and the regeneration exhaust path 14 communicate with each other on the exhaust side, and since the opening 13a of the rotating drum 13 is installed facing the air intake port 18, drying is carried out by one blower 17. It becomes possible to supply air and hot air, and the dehumidification section can have a simple structure.

(f) Effect of the invention According to this invention, the plurality of ventilation passages formed by the moisture-absorbing material are repeatedly moved to both the ventilation passage and the regeneration exhaust passage by the rotation of the rotating drum, so that moisture absorption and regeneration are alternately repeated. By adjusting the rotational speed of the drum or the regeneration temperature, the temperature of the dehumidified air can be controlled to the optimum temperature. Moreover, by providing a regeneration exhaust path that communicates with the exhaust port of the airflow path, outside air and hot air can be exhausted with a single blower, making it possible to simplify and downsize the structure of the dehumidifying section. This has the advantage of providing a dehumidifying drying type grain dryer with a simple structure and low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural diagram of the main structure of the drying section of a grain dryer according to an embodiment of the present invention, FIGS. 2 and 3 are schematic cross-sectional structural diagrams of the structure of the dehumidifying section of the grain dryer, and FIG. The figure is an external perspective view of a rotating drum used in the grain dryer, and FIG. 5 is a control block diagram of the grain dryer. 7, 8... Drying room, 10, 11... Ventilation duct, 1
3... Rotating drum, 13b... Moisture absorbing material, 14...
Regeneration exhaust path, 17... blower, 19... (for regeneration) heater, 21... (drum rotation) motor.

Claims (1)

[Claims] 1. In a grain dryer that dehumidifies and dries grain by sending dehumidified dry air from a vent in a drying room, there is an air passage leading from the atmosphere to the air vent, and an air passage connected to the air passage and one end of which is connected to the exhaust air of the air passage. A plurality of air passages are formed in the radial direction by a regeneration exhaust passage communicating with the opening and a moisture absorption material installed in the side surface of the cylinder, and these air passages are included in both the air blow passage and the regeneration exhaust passage. a rotating drum arranged so that the
A grain dryer comprising: a drum driving device that rotates the circuit drum; a heat source disposed in the regeneration exhaust path; and a blower that guides outside air to the air blowing path and hot air to the regeneration exhaust path.