JP3484485B2 - Grain drying method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grain drying method for maintaining grain quality and improving grain drying efficiency.

[0002]

2. Description of the Related Art Harvested rice will be described below as an example of grain. The harvested rice processing facility must guarantee the quality of the harvested rice during the treatment process of the harvested rice, that is, storage, drying and hulling of the harvested rice. The quality of rice refers to mold, taste, cracking of the harvested rice at the time of storage, skin deviation of brown rice at the time of hulling, and the like. And there is a lot of water in the rice, and
If it is stored for a long period of time, mold will be generated, and if it is overly dried, so-called overdrying will cause deterioration of taste and cracking of the body. Therefore, the water content of rice greatly affects the quality of rice. Also, since rice itself is a living thing, if the temperature is high, the respiration of rice becomes active and the energy inside the rice is consumed (hereinafter referred to as the deterioration of grains), and the quality of rice deteriorates. Since the reproductive activity of rice plants becomes active and causes mold development, which reduces the quality of rice, the temperature of the stored rice itself also has a great influence on the quality of rice.

Therefore, the Ministry of Agriculture, Forestry and Fisheries of the Ministry of Agriculture, Forestry and Fisheries regulates the moisture content of the harvested rice and maintains the quality of the harvested rice as the air flow standard. The air volume per unit weight is fixed. This is called the safety limit air volume ratio. Therefore, if this safety limit air volume ratio is satisfied, for example, the water content is 24%.
It will be judged that it is safe to store 10 tons of harvested rice for 3 days.

Next, the basic technical idea of the present invention will be described. The grain drying efficiency η is the dehydration amount Gkg from the grain per unit total power consumption WH, which is expressed as follows.

Drying efficiency η = dehydration amount Gkg / total power consumption WH ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ And the power of the compressor of the dehumidifier that adjusts the humidity of the drying air, and the total power consumption in (1 set)
WH = Blower power consumption WH1 + Dehumidifier power consumption WH2
It can be expressed as (2 types). Also (1 set)
The amount of dehydration Gkg in is expressed as follows. Dehydration Gkg = (Absolute humidity of exhaust Mx-Absolute humidity of blown air My)
× Ventilation amount V × Specific gravity of blown air γ ... (3 formulas)

Therefore, in order to improve the drying efficiency η, it is necessary to reduce the total power consumption WH and increase the dehydration amount Gkg. Total power consumption in grain drying method
One way to reduce WH is to reduce the air flow to reduce the power consumption WH1 of the blower, and to stop the compressor of the dehumidifier to reduce power consumption WH2 of the dehumidifier.

Next, as a condition for increasing the dehydration amount Gkg, either the value of (absolute humidity Mx of exhaust gas−absolute humidity My of blown air My) is increased or the blown air amount V is increased by the above-mentioned three equations. However, the condition for increasing the value of (Absolute humidity of exhaust air Mx-Absolute humidity of blown air My) is to reduce the absolute humidity My of blown air by removing moisture in the blown air with a dehumidifier as much as possible. Therefore, there is a conflict with reducing the power consumption WH2 of the dehumidifier, and increasing the air flow rate V is also a conflict with reducing the power consumption WH1 of the blower. There is something to do. Therefore, in order to maximize the drying efficiency η, how to adjust the dehydration amount Gkg and the total power consumption WH, which are contradictory to each other, is a key point.

As a method of drying grains, naturally, quality of grains,
That is, the safety limit air volume ratio must be considered. The basic idea of the present invention regarding grain quality is to give priority to grain quality when the moisture content of the grain is very high. That is, at the time of planning, a blower that can blow the amount of air required to maintain the quality of the grain while satisfying the safety margin air volume ratio is selected, and the quality of the grain is maintained by operating this blower at the rated level. In order to improve the drying efficiency, whether the exhaust gas is recycled or not.

In the dehumidifying / drying method, it is generally practiced to recycle the drying air and dry the dehumidifying dryer while gradually lowering the humidity of the blown air in order to efficiently dry the material to be dried. However, the method of drying by recycling differs depending on the type of the material to be dried. For example, when there is a lot of water like medicinal herbs and when the water of medicinal herbs is sufficiently removed to form a powder, a large amount of water is contained in the exhausted air when the water content is high. The exhaust gas is discharged as it is, and when the water content reaches a certain level, the exhaust gas is guided to the dehumidifying dryer again to remove the water content in the exhaust gas and continue to recycle the exhaust gas until the water content of the herbs is sufficiently removed. I try to do it.

Further, when the timber is dried as disclosed in Japanese Patent Publication No. 59-25134, the drying characteristics of the timber,
That is, if only the surface of the timber is dried, the moisture in the core of the timber will be trapped and the drying time will be long, so you can recycle the exhaust or discharge the exhaust as it is so that the surface of the timber does not become overdried. By adjusting the temperature and humidity, the moisture in the core of the timber is efficiently removed and the timber is dried.

Specifically, the wood is dried in four stages. Explaining with reference to FIG. 3, first, in the first stage where the lumber has just been lumbered and the water content is high, the opening degree of the damper 2 is adjusted and a part of the air is supplied to the auxiliary condenser 3
To release outside air, open the damper 5 to take in the outside air, turn off the dehumidifying evaporator 4 condenser 6 and absorb the water content of the wood in the drying chamber 1 to remove the drying air containing a large amount of water. A part of the air is discharged to the outside air through the auxiliary evaporator 3, and the remaining air is mixed with the outside air sucked through the damper 5 in a state where a large amount of water is contained in the dehumidification evaporator 4 without evaporating the contained water. After adjusting the humidity, it passes through the condenser 6 in the OFF state and is recirculated to the drying chamber 1 by the blower 7. This first stage is continued until the absolute humidity of the air in the drying chamber 1 becomes substantially equal to the absolute humidity of the outside air. This promotes drying so that the surface of the wood does not become overdried. Next, in the second to fourth stages, the dampers 2 and 5 are closed, and the dehumidifying evaporator 6 and the condenser 4 are turned on.
In this state, the drying air is circulated in a closed circuit state, and moisture in the circulating drying air is gradually removed by the dehumidifying evaporator 6 and the condenser 4 to suppress overdrying of the surface of the wood. At the same time, the core of the wood is dried evenly.

In the conventional grain drying method shown in FIG. 4 (JP-A-3-87589), when the set humidity is higher than the humidity of the outside air, the damper 9 is closed to stop sucking the outside air and the damper 10 is closed. The drying air is circulated in a closed circuit state, and the humidity of the drying air is gradually lowered to be circulated by the blower 7 so that the grains in the storage tank 1 are prevented from being overdried and the grains are dried. When the set humidity is lower than the humidity of the outside air, the damper 9 and the damper 10 are opened, the outside air is sucked from the damper 9, the dehumidifier 8 dehumidifies, and the grain in the storage tank 1 is dried. The air is exhausted from the ground to prevent the grain from overdrying while drying. Also, the humidity of the outside air is very high,
Alternatively, when the humidity is close to the set humidity, the dampers 9 and 10 are opened halfway to release a part of the air into the atmosphere and circulate the remaining air so as to prevent the grain from overdrying and dry it.

[0013]

The above-mentioned conventional recycling-type drying has problems in terms of drying efficiency. First of all, when drying the herbs, when the water content of the herbs is high, the exhaust air contains a large amount of water, so the exhaust air is discharged as it is, and when the water reaches a certain amount, Since the exhaust gas is guided to the dehumidifying dryer again to remove the water content in the exhaust gas, the exhaust gas is continuously recycled until the water content of the herbs is sufficiently removed. The dehumidifier is operated continuously until the medicinal herbs are completely dried by recycling the exhaust gas,
And, as a result, the blower is also continuously operated in rated operation, and when viewed from the viewpoint of drying the grain that is the subject of the present invention, a large amount of total power consumption is consumed and the drying efficiency is low. is there.

Next, in the conventional example shown in FIG. 3, in the first stage in which the wood has just been lumbered and has a large amount of water, in the first stage, one of the drying air which absorbs the water of the wood in the drying chamber 1 and contains a large amount of water. Part of the air is discharged to the outside air through the auxiliary evaporator 3, and the remaining air is mixed with the outside air sucked through the damper 5 in a state where a large amount of water is contained in the dehumidification evaporator 4 without evaporating the contained water, thereby obtaining an absolute humidity. After adjusting the air conditioner, the air passes through the condenser 6 in the OFF state and is recirculated to the drying chamber 1 by the blower 7, so that the blast humidity becomes high, and as a result, the dehydration amount decreases, and when viewed from the viewpoint of grain drying. There is a problem that the drying efficiency is low. Further, in the second to fourth steps, the drying air is circulated in a closed circuit state, and the moisture in the circulating drying air is gradually removed by the dehumidifying evaporator 6 and the condenser 4 for drying. Therefore, from the viewpoint of drying grains, as in the case of drying the above-mentioned herbs, even when the conditions of the outside air are good, the exhaust gas is recycled without utilizing the outside air. 4 and the blower 7 are continuously in rated operation, resulting in a large total power consumption and a low drying efficiency.

Further, the conventional example shown in FIG. 4 for drying grains has a main purpose of preventing overdrying. Therefore, when the set humidity is higher than the humidity of the outside air (when the conditions of the outside air are good), the humidity Since high air is circulated in a closed circuit state and the humidity of the drying air is gradually lowered by the dehumidifier, the air is circulated by the blower 7, so that the dehydration amount is small and the dehumidifier and the blower must be continuously rated. Therefore, there is a problem that total power consumption increases and drying efficiency is low.

Further, none of the above-mentioned conventional examples describes the control of the air flow rate, and does not disclose the technique of improving the drying efficiency by minimizing the power consumption of the blower related to the drying efficiency.

The present invention has been made in view of the above-mentioned problems, and provides a method for drying a grain in which the drying efficiency is improved by comprehensively examining the dehydration amount, the total power consumption, and the quality of the grain. .

[0018]

Means for Solving the Problems According to the present invention for solving the above-mentioned problems, the grain for drying the grain by introducing the drying air which has passed through the dehumidifier to a storage tank storing the grain by a blower. In the drying method, the temperature and relative humidity of the drying air is compared with the temperature and relative humidity of the exhaust gas discharged from the storage tank so that the relative humidity of the drying air is higher than the relative humidity of the exhaust gas, and or When the temperature of the drying air is lower than the exhaust temperature, the exhaust gas is recycled with a small air volume, and the relative humidity of the drying air is lower than the relative humidity of the exhaust, and / or the temperature of the drying air is higher than the exhaust temperature. It is characterized in that the outside air is sucked in with a large air volume and dried, and then the exhaust air is discharged.

[0019]

Since the present invention is constructed in this way, it has the following actions. That is, the temperature and relative humidity of the drying air for guiding the drying air that has passed through the dehumidifier to the storage tank that stores the grains by the blower and drying the grains and the temperature and the relative humidity of the exhaust gas discharged from the storage tank. Compared with the relative humidity of the drying air is higher than the relative humidity of the exhaust,
And / or when the temperature of the drying air is lower than the exhaust temperature, the exhaust gas is recycled with a small air volume to reduce the air consumption and reduce the power consumption of the blower, and reduce the humidity of the drying air and raise the temperature. It is possible to increase the amount of dehydration by increasing the amount of dehydration, and the fact that the exhaust conditions are better than the drying air conditions means that the grains are considerably dry, so a small air volume is required. But the safety marginal airflow ratio must be met (the grain is safe)
It becomes possible to guarantee the quality. In the present invention, the drying air condition and the exhaust condition are
Is the sky calculated based on each temperature and relative humidity.
Indicates the state of mood (absolute humidity). That is, in the present invention,
Drying air conditions are based on the temperature and relative humidity of the drying air.
The dry air condition (absolute humidity) required based on
In addition, the exhaust condition means the exhaust gas discharged from the storage tank.
Exhaust condition calculated based on temperature and relative humidity (absolute
Humidity).

On the other hand, when the relative humidity of the drying air is lower than the relative humidity of the exhaust air, or when the temperature of the drying air is higher than the exhaust temperature (when the outside air condition is good), the outside air is sucked with a large air volume. By exhausting the exhaust air after drying, it is possible to lower the humidity of the drying air and raise the temperature, and to increase the amount of dehydration by increasing the air volume to increase the drying efficiency. Since a large amount of air is blown and air with good conditions is blown, the safety limit air volume ratio is satisfied and it becomes possible to guarantee the quality of the grain. In addition, the outside air condition of the present invention refers to an air condition (grains that is in equilibrium with moisture after drying of grains).
Air temperature and relative humidity in equilibrium with moisture after drying
Ambient temperature and ambient relative humidity measured to compare
Refers to degrees.

[0021]

EXAMPLE An example of the present invention will be described below. In FIG. 1, the detector 11 detects the relative humidity my and the temperature ty of the outside air and inputs them to the dehumidifier operation determination unit 12 to determine whether to operate the dehumidifier 13. In this judgment, from the relationship between the relative humidity and the temperature regarding the equilibrium moisture of the grain shown in FIG. 2, for example, when the outside air temperature is 5 ° C. and the outside air relative humidity is 55%, the outside air temperature is 40 ° C. and the outside air relative humidity is 69% (A ) Range outside air (outside air condition ) , the grain can be dried up to 14% or less by the outside air in this condition (state) because of the relationship with the equilibrium water content of the grain. The grain can be sufficiently dried without lowering the humidity, and the dehumidifier 13 can be used under the above-mentioned outside air condition (outside air condition).
Will be stopped. As a result, the power consumption WH1 of the dehumidifier 13 becomes zero, and the outside air intake damper 14 is opened to take in the outside air, the exhaust damper 15 is opened and exhausted, and the amount of dehydration G is increased by drying with a large amount of outside air. ,
It is possible to improve the drying efficiency, and since a large air volume is blown under the above-mentioned outside air conditions (outside air conditions) , the safety limit air volume ratio is satisfied, and it is possible to maintain the grain quality with any grain water content. Become.

On the other hand, it is determined that operating the dehumidifier 13 when the detected outdoor air relative humidity my temperature ty at the detector 11 is in the range of shown in FIG. 2 (B) and (C), the time the grain safety determination unit 16, whether grain is safe or not. In addition, in the present example, the grain is safe means that the air volume per unit weight of the stored grain necessary for maintaining the quality of the grain determined based on the moisture content of the grain and the storage days of the grain specified by the Ministry of Agriculture , Forestry and Fisheries . The official standard (safety limit air volume ratio) is secured , and appropriate treatment is performed.
That the grain is not safe and that the grain is not safe.
The air volume ratio is not secured, and moreover, it is not properly treated.
It refers to the state that is not open . The safety of the grain is judged by detecting the relative humidity Mx and the temperature Tx of the exhaust gas by the detector 17 and inputting these signals to the grain safety judging section 16 from the equilibrium moisture relationship shown in FIG. It is possible to know the water content of the grain in the tank 1. For example, exhaust humidity Mx is 80%, exhaust temperature
When Tx is 20 ° C, it is on the line of moisture 18% in Fig. 2.
It is determined that the water content of the grain in the storage tank 1 is 18%.

Exhaust conditions ( exhaust from the storage tank
Exhaust condition calculated based on exhaust temperature and relative humidity
(Absolute humidity)) is in the range of (B) in FIG. 2, that is, when the exhaust temperature is 5 ° C., the exhaust relative humidity is 55% to 75% to the exhaust temperature 40 ° C., and the exhaust relative humidity is 69% to 87%. The water content of the grain in the tank 1 is in the range of 14% to 18%, and it is judged that it is safe even with a small air volume, and this judgment signal is input to the recycling / air volume judgment section 18. In the recycle / air volume determination unit 18, the relative humidity mx and temperature tx of the drying air input from the detector 21 and the relative humidity mx and the temperature Tx of the exhaust air input from the detector 17 are used to determine the relative humidity m of the drying air.
x and the relative humidity Mx of the exhaust air and the temperature tx of the drying air and the exhaust temperature Tx are compared, and when the relative humidity mx of the drying air is equal to or higher than the relative humidity Mx of the exhaust, and / or the temperature tx of the drying air is When the temperature is equal to or lower than the exhaust temperature Tx, the blower control unit 20 outputs a small amount of air to control the blower 7, and the amount of air is small and the outside air intake damper 14 and the exhaust damper 15 are closed to recycle the exhaust gas. Airflow condition).

As described above, since the dehumidifier 13 is operated and it is determined that the grain is safe, and the exhaust condition is better for the drying of the grain, the safety limit air volume is small even if the air volume is small. The ratio is satisfied and the quality of the grain is guaranteed, and
The air volume is reduced to reduce the power consumption WH1 of the blower 7,
Furthermore, the relative humidity Mx of the exhaust is lower than the relative humidity mx of the drying air, and / or the exhaust temperature is higher than the temperature tx of the drying air.
By recycling exhaust gas having a high Tx and dehumidifying it with the dehumidifier 13, it is possible to further lower the relative humidity mx of the drying air, increase the temperature tx, increase the dehydration amount G, and improve the drying efficiency. .

The following may be considered as a mode in which the above-mentioned recycle small air volume condition is satisfied. Dehumidifier 13 in normal case
Since the humidity of the drying air is lowered and the temperature thereof is raised by the above, the humidity of the drying air is not higher than that of the exhaust gas and the temperature is not lower than that of the exhaust gas. There are the following cases. That is, when the outside air temperature becomes low in cold regions or in winter, the dehumidifier 13 is frosted, so this defrosting must be performed. In this case, the defrost removed in this case may be contained as moisture in the air, and the exhaust conditions (temperature of exhaust exhausted from the storage tank and
And the exhaust condition (absolute humidity)
Air temperature for drying (temperature and phase of drying air )
Condition of drying air calculated based on humidity (absolute humidity
Degree)) may be worse. Further, as another aspect, when the air is blown at a humidity higher than the equilibrium moisture, the moisture of the drying air may be absorbed by the grains and the exhaust conditions may be better.

Further, when the relative humidity mx of the drying air is lower than the relative humidity Mx of the exhaust air in the recycle / air volume judging unit 18,
And / or when the temperature tx of the drying air is higher than the exhaust temperature Tx, the fan 7 is controlled by being input to the large air volume portion of the blower control unit 20, and the outside air intake damper 14 and the exhaust damper 15 are opened with a large air volume and exhausted. (Hereinafter, this condition is referred to as a non-recycled large air volume condition).

That is, the non-recycled large air volume condition means that the grain is sufficiently dehydrated, the heat of the air is taken away by the heat of evaporation of the moisture of the grain, the exhaust temperature Tx is lowered, and the moisture is absorbed. Since it means that the exhaust gas relative humidity Mx rises, the drying efficiency can be improved by taking in the air in good condition to discharge the exhaust gas with a large amount of water, and by increasing the air volume to increase the dehydration amount G. It will be possible to improve.

Under the above non-recycled large air volume condition, the outside air has a high relative humidity and a low outside temperature due to rain.
In some cases (outside air condition), it may not be possible to sufficiently lower the humidity of the drying air and raise the temperature thereof due to the dehumidifying capacity of the dehumidifier 13. Therefore, outside air conditions
Depending on (the state of the outside air) , the drying air condition may be worse than the exhaust condition. In such a case, the recycle small air volume condition is satisfied, and the drying by the recycling is automatically performed with the small air volume, and the drying efficiency can be improved.

Next, the grain safety judgment unit 16 is not safe ,
That is , when it is determined that the safety limit air volume ratio is not secured , the determination signal is the recycle / non-recycle determination unit.
The air blower 7 is controlled by being input to the large air volume part of the blower control unit 20 while giving priority to the safety of grain. That is, in FIG. 2, when the exhaust temperature Tx is 5 ° C. and the exhaust relative humidity Mx is 75% or more to the exhaust temperature Tx 40 ° C. and the exhaust relative humidity Mx is 87% or more (C), grain is not safe (high it is determined that water in a), achieving this time to to ensure blows large volume in the storage tank 1 safety limit air flow ratio the safety of grain in the first, and, exhaust relative humidity than the relative humidity mx of drying air By lowering the relative humidity mx of the drying air by recycling exhaust gas having a low Mx and / or a temperature Tx higher than the temperature tx of the drying air and dehumidifying with the dehumidifier 13,
At the same time, the temperature tx is increased to increase the dehydration amount G to improve the drying efficiency, and when the relative humidity mx of the drying air is lower than the relative humidity Mx of the exhaust, and / or the temperature tx of the drying air.
Is higher than the exhaust temperature Tx, a large air volume is provided, and the outside air intake damper 14 and the exhaust damper 15 are opened to exhaust the exhaust gas, and a large air volume is provided to increase the dehydration amount G, whereby the drying efficiency can be improved. .

Also in this case, as in the case of the above-mentioned non-recycled large air volume condition, the relative humidity of the outside air is high or the outside air temperature is high due to rainy weather.
Low ambient conditions (ambient air conditions) Sometimes, by lowering the humidity of the sufficiently dried air by dehumidifying capacity of the dehumidifier 13, and,
It may not be possible to raise the temperature. Therefore, depending on the outside air conditions (outside air conditions ) , the drying air conditions (dry
Drying calculated based on the temperature and relative humidity of the drying air
Write exhaust conditions of use air condition (absolute humidity)) (or reservoir
It is calculated based on the temperature and relative humidity of the exhaust gas discharged from
It may be worse than the exhaust condition (absolute humidity) . In such a case, the above recycling conditions are met,
Drying by recycling is automatically performed with a large air volume, and it becomes possible to improve the drying efficiency by giving priority to the safety of grains.

In this way, the exhaust conditions ( exhaust from the storage tank
Emissions calculated based on the temperature and relative humidity of the exhaust gas emitted
By detecting the air condition (absolute humidity) with the detector 17 and determining the water content of the grain in the storage tank 1, the exhaust air condition ( air temperature of the exhaust gas discharged from the storage tank is used by utilizing this exhaust condition.
Exhaust condition calculated based on temperature and relative humidity (absolute humidity
Degrees)) compared to determine the amount of blown air with determining whether to recycle exhaust and dehydration amount, becomes the quality of the total power consumption and grains can be improved drying efficiency Overall.

In the above description, the relationship between the equilibrium moisture content of the grain and the humidity and temperature is shown in FIG. 2 as a criterion for the determination of the dehumidifier operation determination unit 12 and the grain safety determination unit 16, but ranges (A), ( B) and (C) are not limited to this, and this range can be set arbitrarily.

[0033]

As described in detail above, according to the present invention, the temperature and relative humidity of the drying air and the temperature and relative humidity of the exhaust gas discharged from the storage tank are compared to determine the relative humidity of the drying air. When the temperature of the drying air is higher than the relative humidity of the exhaust gas and / or the temperature of the drying air is lower than the exhaust temperature, the exhaust gas is recycled with a small air volume to reduce the power consumption of the blower and reduce the power consumption of the blower. The humidity can be lowered and the temperature can be raised to increase the amount of dehydration to increase the drying efficiency. Also, the fact that exhaust conditions are better than air conditions for drying means that the grains are considerably dry. Since this means that the safety limit air volume ratio is satisfied even with a small air volume, quality can be guaranteed.

On the other hand, when the relative humidity of the drying air is lower than the relative humidity of the exhaust air and / or the temperature of the drying air is higher than the exhaust temperature, the outside air is sucked in with a large air volume to dry the exhaust air. By discharging, it is possible to lower the humidity of the drying air and raise the temperature, and to increase the amount of dehydration by increasing the air volume to increase the drying efficiency. Therefore, the safety limit air volume ratio is satisfied and the quality of the grain can be guaranteed.

When the dehumidifier operation determination unit determines whether or not to operate the dehumidifier according to the outside air conditions, and when it is determined that the dehumidifier is not operated, the outside air is sucked in with a large amount of air and dried, and then the exhaust gas is discharged. As a result, it is possible to reduce the power consumption of the dehumidifier to zero and reduce the total power consumption, and to dry the grain with a large amount of outside air to increase the dehydration amount and improve the drying efficiency, It is possible to maintain the quality of grain by ensuring the safety limit air volume ratio by blowing air.

On the other hand, when it is determined that the dehumidifier is to be operated, the grain safety determination unit determines whether or not the grain is safe, based on the exhaust conditions, and when it is determined that the grain is safe, the temperature of the drying air and the relative temperature are set. Recycle exhaust with a small air flow when humidity is compared to exhaust temperature and relative humidity, and the relative humidity of the drying air is higher than the relative humidity of the exhaust and / or the temperature of the drying air is lower than the exhaust temperature. As a result, the quality of the grain is guaranteed, and the relative humidity is lower than the drying air and higher than the temperature of the drying air, so that the exhaust gas is recycled to lower the humidity of the drying air and increase the temperature to increase the dehydration amount. It is possible to increase the air flow rate and further reduce the air flow rate to reduce the power consumption of the blower and improve the drying efficiency.

On the other hand, when the relative humidity of the drying air is lower than the relative humidity of the exhaust air and / or the temperature of the drying air is higher than the exhaust temperature, the outside air is sucked and dried with a large air volume, and then the exhaust air is exhausted. The quality of the grain is guaranteed by discharging the air, and the relative humidity is lower than the exhaust air and the outside air is taken in to reduce the blast humidity and increase the temperature of the drying air, so that it is dried by a large amount of the outside air. Then, by exhausting, the dehydration amount can be increased and the drying efficiency can be improved.

When it is determined that the grain is not safe, a large air volume is set and the drying air condition and the exhaust condition are compared to determine whether the exhaust gas is recycled or not.
It is possible to increase the amount of dehydration while ensuring the grain quality by satisfying the safety limit air volume ratio, and to lower the humidity of the drying air by determining whether to recycle and raise the blast temperature to improve the drying efficiency. it can. As a result, it is possible to obtain a grain drying method in which the drying efficiency is improved by comprehensively considering the dehydration amount, the total power consumption, and the grain quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the equilibrium moisture content of grains, the temperature of outside air and the temperature of exhaust gas, and the relative humidity.

FIG. 3 is a flow diagram of a conventional example.

FIG. 4 is a flow diagram of another conventional example.

[Explanation of sign]

1 storage tank 7 blower 11 detector 12 Dehumidifier operation determination unit 13 Dehumidifier 14 Outside air intake damper 15 Exhaust damper 16 Grain Safety Judgment Department 17 detector 18 Recycling / Air flow rate determination section 19 Recycling / Non-Recycling Judgment Department 21 detector mx Relative humidity of drying air tx drying air temperature Mx exhaust relative humidity Tx exhaust temperature My outside air humidity ty outside temperature

Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI F26B 21/04 F26B 21/04 A 21/12 21/12 (56) Reference JP-A-3-95386 (JP, A) JP-A-59 -119173 (JP, A) JP-A 1-230981 (JP, A) JP-A 5-23 (JP, A) JP-A 5-49343 (JP, A) JP-A-6-237687 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F26B 21/00 A01F 25/00 B01D 53/26 F26B 9/06 F26B 21/04 F26B 21/12

Claims (4)

(57) [Claims] 1. A method for drying grains, in which drying air that has passed through a dehumidifier is guided to a storage tank that stores the grains by a blower to dry the grains, wherein the temperature and relative humidity of the drying air and the storage tank are used. Exhaust gas is recycled with a small air volume when the relative humidity of the drying air is higher than the relative humidity of the exhaust air by comparing the temperature and the relative humidity of the exhaust air and / or the temperature of the drying air is lower than the exhaust temperature. However, when the relative humidity of the drying air is lower than that of the exhaust air and / or the temperature of the drying air is higher than the exhaust temperature, the outside air is sucked in with a large amount of air to dry the exhaust air. Characteristic grain drying method. 2. A method for drying grains, in which drying air that has passed through a dehumidifier is introduced into a storage tank that stores the grains by a blower to dry the grains, in the relative humidity and temperature of exhaust gas discharged from the storage tank. Determine the water content of the grains in the storage tank by using the
The temperature and relative humidity of the drying air is compared with the temperature and relative humidity of the exhaust gas discharged from the storage tank so that the relative humidity of the drying air is higher than the relative humidity of the exhaust gas, and / or the temperature of the drying air. Is recycled below the exhaust temperature, and after the relative humidity of the drying air is lower than the relative humidity of the exhaust, and / or the temperature of the drying air is higher than the exhaust temperature, the outside air is sucked in and dried. A method for drying a grain characterized by discharging the exhaust gas. 3. A grain drying method in which drying air that has passed through a dehumidifier is introduced by a blower to a storage tank that stores grains to dry the grains, and whether or not the grains are safe in a grain safety determination unit. Was judged according to the exhaust condition of the exhaust gas discharged from the storage tank , and when it was judged to be safe, the temperature and relative humidity of the drying air were compared with the temperature and relative humidity of the exhaust gas. When the relative humidity of the drying air is higher than the relative humidity of the exhaust and / or the temperature of the drying air is lower than the exhaust temperature, the exhaust air is recycled with a small air volume so that the relative humidity of the drying air is higher than the relative humidity of the exhaust. When the temperature of the drying air is also lower than that of the exhaust air or the temperature of the drying air is higher than the exhaust gas temperature, the exhaust air is exhausted after sucking the outside air with a large air volume and drying.
If you determine that the grain is not safe, increase the air volume.
A method for drying grains, which comprises comparing the air condition for drying with the exhaust condition to determine whether to recycle the exhaust. 4. A grain drying method for drying grain by introducing drying air that has passed through the dehumidifier to a storage tank storing the grain by a blower, and dehumidifying whether or not to operate the dehumidifier depending on outside air conditions. When the dehumidifier operation judgment unit judges that the dehumidifier is not operated, it sucks the outside air with a large air volume to dry it and exhausts the exhaust gas discharged from the storage tank , and when it is judged that the dehumidifier is operated, grain safety The judging unit judges whether the grain is safe or not based on the exhaust conditions, and if it is judged to be safe, the temperature and relative humidity of the drying air is compared with the temperature and relative humidity of the exhaust air to determine whether When the relative humidity is higher than the relative humidity of the exhaust and / or the temperature of the drying air is lower than the temperature of the exhaust, recycle the exhaust with a small air volume and the relative humidity of the drying air is lower than the relative humidity of the exhaust. And / or when the temperature of the drying air is higher than the exhaust temperature, the outside air is sucked in with a large air volume to dry and then the exhaust air is discharged, and if it is judged that the grain is not safe, a large air volume is used for drying. A method for drying grains, which comprises comparing air conditions and exhaust conditions to determine whether to recycle exhaust.