JPH038474B2 - - 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. In order to perform such low-temperature drying, dehumidifying grain drying is put into practical use. In conventional dehumidifying and drying grain dryers, dehumidified air is 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 the drying method in which dehumidified air is directly introduced into the 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.

(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: a blower path leading from the atmosphere to a vent in a drying room; and a hot air supply path attached to the blower path and having one end open to the atmosphere. , a rotating drum having a plurality of ventilation passages formed in the axial direction by a moisture-absorbing material housed in a cylinder, and arranged so that the ventilation passages are included in both the air blowing passage and the hot air supply passage; It is characterized by having a drum drive device that rotates a rotating drum, a blower that guides outside air to the air passage, and a hot air generator that is disposed in the hot air supply path and generates hot air to be supplied to the air passage of the rotating drum. do.

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

The grains 2 loaded in the storage tank 1 are stored in a drying room 7,
A circulation path is connected from the storage tank 1 to the drying chambers 7 and 8 by rotary valves 4 and 5 provided below the storage tank 8 and a screw conveyor 6, and a circulation device 3 such as a bucket elevator installed outside the storage tank 1. 9 and then transported to the storage tank 1 again. 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 have a mesh 19 installed inside and outside thereof with a mesh size that does not allow the grains 2 to pass through, and has a plurality of ventilation holes. The ventilation holes on the inside of the drying chambers 7 and 8 communicate with a blower passage 22, which will be described later, and the ventilation holes on the outside communicate with exhaust passages 10 and 11, which will be described later, respectively. The air passage 22 is a passage for introducing dry air obtained by dehumidifying the outside air taken in through the air intake port 25 to the ventilation holes of the drying chambers 7 and 8. The exhaust air passages 10 and 11 both communicate with the atmosphere through an exhaust port 24. A blower 16 is provided near the exhaust port 24, and the blower 16 sucks dry air from the air passage 22, passes through the drying chambers 7, 8, the exhaust passages 10, 11, and then discharges it from the exhaust port 24.
Below the air passage 22, an exhaust port 2 is formed at one end.
At 6, a hot air supply path 23 communicating with the atmosphere is provided. A rotating drum 13 is provided between the air blowing path 22 and the hot air supply path 23 so that its rotating shaft is located parallel to the rotating shaft.

The rotating drum 13 has a rotating side surface on which the transmission belt 14 is stretched, and a moisture-absorbing material 13a is provided inside the cylinder.
It's decorated. The moisture absorbing material 13a is a corrugated substrate of paper or polyester coated with a moisture absorbent such as lithium chloride, or a nonwoven fabric impregnated with a moisture absorbent and processed into a honeycomb structure. The moisture absorbing material 13a is wound around the rotating shaft of the rotating drum 13 so that a cavity formed by a corrugated substrate or nonwoven fabric is parallel to the axial direction of the rotating drum 13, and the cavity forms a ventilation path of the rotating drum 13. ing.

As described above, since the rotating drum 13 is located between the air passage 22 and the hot air supply passage 23, the upper half of the air passage is included in the air passage 22, and the lower half of the air passage is included in the hot air supply passage 23. Rotating drum 13
It receives driving force from a motor 15 via a transmission belt 14 to rotate. The hot air supply path 23 is provided with a regeneration heater 18 on the side of the dryer body and a blower 17 on the side of the exhaust port 26 with the rotating drum 13 as the center. A partition plate (not shown) is provided between the heater 18 and the rotating drum 13, and as shown in FIG. Only the hot air is allowed to pass through. Further, a filter 25a is attached to the air intake port 25 of the air passage 22 to remove dust from the outside air. In addition, storage tank 1
A moisture meter 12 is attached to measure the moisture content of the grain. Furthermore, an outside air temperature sensor 20 and an outside air humidity sensor 2 are provided on the outside wall of the dryer body for measuring outside air temperature and outside air humidity, respectively.
1 is attached.

FIG. 3 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 20, and the outside air humidity sensor 21 are led to the controller 27 as input parameters to the controller 27. The stop water content setting device 30 is comprised of a setting volume arranged on a control panel (not shown) for setting a desired stop water content, and the setting value is set by the control unit 2.
Guided by 7. The control unit 27 controls the rotation speed control circuit 28 so that the temperature of the dehumidified air reaches an optimum value according to a pre-stored low temperature drying program and based on each input parameter of measured moisture content, stopped moisture content, outside air temperature, and outside air humidity. and outputs a control signal to the heater temperature control circuit 29. The rotation speed control circuit 28 controls the rotation speed of the drum rotation motor 15 according to instructions from the control section 27 . The heater temperature control circuit 29 controls the current supplied to the regeneration heater 18 according to instructions from the control section 27 .

In the grain dryer configured as above,
The air exhaust passages 10 and 11 of the air passage 22 communicate with each other via the drying chambers 7 and 8, so when the blower 16 is activated as shown in FIG. More outside air is taken in. The outside air taken in passes through the ventilation path of the rotating drum 13 and is guided in the direction of arrow C. When the outside air passes through the ventilation path of the rotating drum 13, it is dehumidified and dried by the moisture absorbent applied to the moisture absorbent 13a. The air dried in this way is sent from the air passage 22 to the drying chambers 7 and 8.
The grains in the drying chambers 7 and 8 are dried by passing through the drying chambers 7 and 8. Drying room 7,
The air that has passed through the drying chambers 7 and 8 passes through the ventilation holes on the outside of the drying chambers 7 and 8 and is led to the exhaust port 24 as shown by arrow D. On the other hand, similarly to the operation of the blower 16, the hot air supply 2
3, current is supplied to the regeneration heater 18.
Then, the hot air supply path 23 is activated by the operation of the blower 17.
Hot air is supplied to the ventilation passage of the rotating drum 13 included in the rotary drum 13. The ventilation path on the hot air supply path 23 side receives the hot air generated by the regeneration heater 18 and releases absorbed moisture. The hygroscopic agent is regenerated by releasing absorbed moisture and generates latent heat during regeneration. The latent heat generated at this time is used to warm the dry air supplied to the drying chambers 7 and 8.

As described above, the rotation of the rotary drum 13 causes each ventilation passage to alternately move between the blowing passage 22 and the hot air supply passage 23, whereby the outside air absorbs moisture and is warmed by latent heat. Therefore, when the temperature or humidity of the outside air or both of them change, the temperature of the dry air can be controlled by changing the number of revolutions of the rotating drum 13 or the temperature of the hot air generated by the regeneration heater 18. Can be done.
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 18, the regeneration speed of the moisture absorbent material can be increased, thereby increasing the temperature of the dry air.

As described above, the ventilation path of the rotating drum 13 moves alternately between the air blowing path 22 and the hot air supply path 23, so that the rotating drum acts as a latent heat exchanger, and the temperature of the dehumidified air can be controlled with high precision. Can be done.
Therefore, even if the temperature and humidity of the outside air change, optimal low-temperature drying can be performed by controlling the rotational speed of the rotary drum 13 and the temperature of the regeneration hot air. In addition, it has a simple structure that only includes a rotating drum 13 with a moisture-absorbing material inside and a heater for generating hot air for regeneration, and does not require a heat source with a large amount of heat required to heat the dry air. This makes it possible to construct a dehumidifying grain dryer at low cost.

(e) Effects of the Invention According to the present invention, the plurality of ventilation channels formed by the moisture absorbing material are repeatedly moved to both the air blowing channel and the hot air supply channel by the rotation of the rotating drum, so that moisture absorption and regeneration of the moisture absorbing material are possible. are repeated alternately, and the temperature of the dehumidified air can be controlled to the optimum temperature by adjusting the rotation speed of the drum or the regeneration temperature. Since it is possible to control the optimal temperature of the dehumidified air in this way, it is possible to perform optimal low-temperature drying according to the temperature and humidity of the outside air, and it is also possible to use a rotating drum as a grain dryer that can perform such optimal low-temperature drying. It has the advantage of being easy to configure with a regeneration heat source and being inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a schematic structural diagram showing the main structure of the drying section of a grain dryer according to an embodiment of the present invention, Fig. 2 is a schematic structural diagram showing the structure of the dehumidifying section of the grain dryer, and Fig. 3 is the same. FIG. 3 is a control block diagram of a grain dryer. 7, 8...Drying room, 10,11...Exhaust duct, 1
3... Rotating drum, 13a... Moisture absorbing material, 15...
(for drum rotation) motor, 16, 17... blower,
18... (regeneration) heater, 22... ventilation path, 2
3...Hot air supply path.

Claims (1)

[Claims] 1. In a grain dryer that dehumidifies and dries grain by sending dehumidified dry air through 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 air passage with one end open to the atmosphere. A plurality of ventilation passages are formed in the axial direction by a hot air supply passage and a moisture absorption material housed in a cylinder, and the rotation passages are arranged so that the ventilation passages are included in both the air supply passage and the hot air supply passage. The apparatus includes a drum, a drum drive device that rotates the rotating drum, a blower that guides outside air to the air blowing path, and a hot air generator that is disposed in the hot air supply path and generates hot air to be supplied to the airflow path of the rotating drum. Grain dryer.