JP3200715B2 - Method and apparatus for drying grain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drying apparatus for a grain drying and dehumidifier which is used in a grain drying and storing apparatus. A method and an apparatus therefor.

[0002]

2. Description of the Related Art Harvested rice will be described below as an example of cereals. At present, as one means for reforming the marketability of the harvested rice, it is instructed to reduce the construction cost of the harvested rice processing facility and to reduce the unit cost of using the harvested rice processing facility per farmhouse. On the other hand, as a requirement to reform this marketability, the quality of rice must be guaranteed for a harvested rice processing facility.

[0003] The quality of the rice mentioned above refers to mold, taste, cracks in the harvested rice at the time of storage, and misalignment of brown rice during hulling. If the rice has a lot of moisture and is stored for a long period of time, mold will form, and if it is overdried, so-called overdrying will cause a decrease in taste and cracking of the body. Taste is reduced. Therefore, the moisture content of rice greatly affects the quality of rice. Also,
Because rice itself is a living thing, when the temperature is high, the respiration of the rice becomes active and the energy inside the rice is consumed (hereinafter referred to as cereal degradation), and the quality of the rice decreases, and when the temperature is high, the growth of microorganisms The temperature of the stored rice itself has a great effect on the quality of the rice, because the rice becomes active and causes mold generation and deteriorates the quality of the rice.

Therefore, the Ministry of Agriculture, Forestry and Fisheries uses the unit of stored rice with respect to the moisture content and the storage days of harvested rice (kind of cereal) as a standard of air flow for adjusting and maintaining the moisture content of harvested rice and maintaining the quality of harvested rice. The air volume per weight is determined. This is called the safety limit air volume ratio. Therefore, if this safety limit air volume ratio is satisfied, for example, the moisture content is 24%.
It is judged that it is safe to store 10 tons of harvested rice for three days.

Now, a conventional drying apparatus will be described with reference to FIGS. 6 and 7. FIG. In the related art, in order to maintain the dehumidifying efficiency of the dehumidifier 1 and improve the processing efficiency, the processing air volume of the dehumidifier 1 is controlled according to the condition of the outside air. For example, the outside air in rainy weather contains a large amount of water, and this water easily reaches the dew point, so that the removal of the water is easy, so that the processing air volume of the dehumidifier 1 can be increased, and When the moisture contained in the outside air is relatively low in some cases, it is not easy for the moisture to reach the dew point, and it is difficult to remove the moisture. The processing efficiency of the maximum air flow that can be processed according to the outside air condition, that is, the processing efficiency is increased while controlling the processing air flow and maintaining the dehumidifying efficiency of the dehumidifier.

In order to enable such control, the air outlet duct 8 of the dehumidifier 1 and the air suction duct 7 of the blower 2 are joined so that the outside air is sucked only from the outside air suction port of the dehumidifier 1. In this state, the dehumidifier 1 and the blower 2 are connected. Then, the primary air 11 sucked into the dehumidifier 1 is dehumidified while passing through the evaporator 5 and the condenser 6, while the flow rate of the secondary air 12 is adjusted from the secondary air suction port 9 by the damper 10 and the secondary air 12 is sucked. The dehumidified primary air 11 and secondary air 12 are mixed in the blower 2, discharged from the air discharge port 13 of the blower 2, and supplied to a grain storage bin (not shown).

[0007]

SUMMARY OF THE INVENTION In the above conventional example,
The air outlet duct 8 of the dehumidifier 1 and the air suction duct 7 of the blower 2 are joined to control the processing air volume of the dehumidifier 1 in accordance with the outside air condition.

First, in describing this problem, an air flow balance between the primary air flow and the secondary air flow will be described with reference to FIG. The primary air dehumidified by the dehumidifier 1 and the secondary air that is not dehumidified are mixed, and air having a predetermined temperature and humidity is supplied to each storage bin 3 by the blower 2.

That is, the required air volume G3 is the total air volume of the primary air volume G1 and the secondary air volume G2.
G3 is the maximum moisture content of the grain 4 stored in the storage bin 3, the condition of the outside air (for example, outside air in rainy weather), and the maximum storage amount of the grain 4 stored in the storage bin 3 (these conditions are for dry storage of the grain). It is determined from the safety critical airflow ratio determined by the most severe conditions), which guarantees the grain quality.

On the other hand, as the pile height H of the grain 4 increases, the resistance of the air passing through the grain 4 increases.
G3 is at a minimum, and when the stacking height H is at a minimum, the airflow G3 is at a maximum. Also, if the flow velocity of the air passing through the dehumidifier is too fast, moisture condensed in the evaporator is carried on the air flow and the dehumidification efficiency of the dehumidifier is substantially reduced. Usually it should be 2 to 5 m / sec.

[0011] Then, from the viewpoint of quality assurance of the harvested rice, the blower is used for the grain height H, which is the strictest condition for dry storage.
When the value is maximum (when the air volume is minimum), a model is selected that has the performance of obtaining the required air volume G3 that satisfies the safety limit air volume ratio. Explaining concretely by assuming a numerical example that is easy to understand, a blower having the performance of the air volume G3MIN = 300 m ³ / min when the pile height H of the grain obtained from the safety limit air volume ratio is the highest (minimum air volume) is obtained. From the performance curve of this blower, the air volume when the pile height H of the grain is the lowest (maximum air volume)
G3MAX = 500 m ³ / min is determined.

Therefore, conventionally, the processing air flow rate of the dehumidifier is controlled to maximize the processing capacity of the dehumidifier. Therefore, in the above numerical example, G3MAX = 500 m ³ / min in rainy weather.
It is necessary to have a dehumidifier that can process the air volume of the air and that the air velocity passing through the dehumidifier is 2 to 5 m / sec. Control is performed in accordance with the conditions. For example, the processing air volume in the dehumidifier is set to 300 m ³ / min, and the insufficient air volume of 200 m ³ / min is supplemented by secondary air. As described above, a dehumidifier having a size having an air passage area capable of processing the maximum air volume was required, so that the heat exchanger became large and became an expensive dehumidifier, and the processing air volume of the dehumidifier was controlled. The dehumidifier must be designed each time in accordance with each condition, and it becomes impossible to use a commercially available dehumidifier, so that the dehumidifier becomes an expensive dehumidifier, and there is a problem that the facility use unit price per farmhouse increases.

Since the amount of air to be processed by the dehumidifier changes depending on the outside air condition and the pile height of the grains, a control device using an expensive computer is required to control the amount of air to be processed by the dehumidifier. There is a problem that the facility use unit price per house increases.

Since the above-mentioned problem is caused by controlling the processing air volume of the dehumidifier, the processing air volume of the dehumidifier may be kept constant.
Air outlet duct 8 and air suction duct 7 of blower 2
Are joined, there is the following problem. In other words, in order to keep the processing air volume of the dehumidifier constant, the safety limit is set when the pile height H of the grain, which is the strictest condition for dry storage from the viewpoint of quality assurance of harvested rice, is maximum (when the air volume is minimum). The air passage area of the dehumidifier must be determined, and the size of the heat exchanger must be determined so that the air volume satisfying the air volume ratio can be substantially processed with the best dehumidification efficiency.

Therefore, assuming a numerical example that is easy to understand specifically as described above, first, the air volume G3MIN = 300 m when the grain stacking height H obtained from the safety limit air volume ratio is the highest (minimum air volume) A blower having a performance of ³ / min is determined, and a flow rate G3MAX = 500 m ³ / min when the pile height H of the grain is the lowest (maximum air flow) is determined from the performance curve of the blower.

It is sufficient to treat the entire air volume G3MIN = 300 m ³ / min with a dehumidifier. However, since the speed of air passing through the dehumidifier increases and the actual dehumidifying efficiency decreases, the most dehumidifier is used. Find the air volume G1 = 100 m ³ / min that can be processed efficiently and supplement the insufficient air volume 200 m ³ / min with secondary air. Therefore, the fluctuation range of the secondary air amount is 400 m ³ / secondary air amount (from the formula of G2 = G3−G1) when the pile height is the lowest.
min, and the secondary air volume G2 at the highest
0 m ³ / min.

Therefore, this large amount of secondary air (400 m ³ / mi
In order to suck n) from the secondary air suction port 9 with a low suction pressure required to make the air flow rate in the dehumidifier 2 to 5 m / sec, the flow area of the secondary air suction port 9 is equivalent. Therefore, there is a problem that the external dimensions of the dehumidifier become unnecessarily large.

The present invention simplifies the control of the processing air volume by assuring the quality of the cereal, making the processing air volume of the dehumidifier constant by reducing the secondary air suction port, and using a commercially available dehumidifier. An object of the present invention is to provide a method and an apparatus for drying cereals in which the unit cost per farmhouse is reduced by making it possible.

[0019]

The drying method according to the present invention for solving the above-mentioned problems is characterized in that the total air volume of the primary air dehumidified by the dehumidifier and the tertiary air not dehumidified by the dehumidifier is the minimum air volume of the drying air. It is characterized by controlling the air flow that changes according to the pile height of the grain with the secondary air to control from the minimum air flow to the maximum air flow,

As an apparatus for carrying out this method, drying air obtained by mixing air dehumidified by a dehumidifier and outside air not dehumidified by a dehumidifier is supplied to a grain storage bin by a blower to store and dry the grains. In a grain drying apparatus for separating the outside air into secondary air and tertiary air, a gap is provided between an air outlet of the dehumidifier and an air suction port of the blower to suck the tertiary air. In addition to forming a tertiary air suction air passage, a suction port for the secondary air is separately provided, and a damper for air volume adjustment is provided in the secondary air suction port.

[0021]

According to the present invention, the following operations are provided. That is, the outside air of the drying air obtained by mixing the air dehumidified by the dehumidifier and the outside air is separated into secondary air and tertiary air, and a gap is provided between the air outlet of the dehumidifier and the air suction port of the blower. In addition to sucking tertiary air from a tertiary air suction air path formed by providing a suction port for secondary air, a secondary air suction port is provided with a damper for air volume adjustment to adjust the secondary air amount. The total air volume of the primary air dehumidified by the dehumidifier and the tertiary air that is not dehumidified by the dehumidifier so that the total air volume is the minimum air volume of the drying air, and the secondary air volume that changes according to the pile height of the grain is Since it was adjusted by air to control from the minimum air volume to the maximum air volume,
Since the air volume control of the required air volume that changes according to the pile height of the grains may be performed by adjusting the opening of the damper provided in the secondary air suction port, the air volume control of the required air volume can be simplified. .

Further, since the tertiary air is sucked through the gap formed between the air outlet of the dehumidifier and the air suction port of the blower, the fluctuation of the pressure (or air flow rate) in the dehumidifier is reduced, and The drift of the primary air in the dehumidifier is alleviated, and the control of the required air volume can be further simplified. In addition, by setting the minimum required air volume to the total air volume of the primary air volume and the tertiary air volume, the secondary air volume can be reduced, and the suction port for the secondary air can be reduced. The responsiveness is improved, and the above control can be made easier.

As described above, since the minimum required air volume is fixed as the total air volume of the primary air volume and the tertiary air volume, the required air volume can be controlled only by controlling the air volume of the secondary air. Since no control is required and the processing air volume of the dehumidifier is constant, a commercially available dehumidifier can be used.

Also, since the air outlet duct of the dehumidifier is inserted into the suction port of the blower indirectly and connected,
Since the vibration of the blower is not transmitted to the dehumidifier, no special consideration on the strength is required, and since the connection with the blower is indirect, it can be connected even if the type of blower changes, and On the other hand, versatility can be provided, and a commercially available dehumidifier can be used from the viewpoint of the structure.

[0025]

An embodiment of the present invention will be described below. The apparatus for carrying out the method according to the present invention will be described with reference to FIG. 1 showing a front view of the present embodiment and FIG. 2 showing a plan view. The dehumidifier 1 and the blower 2 They are connected indirectly with the outlet duct 14 inserted. As shown in FIG. 3, a gap is provided between the suction port 7 of the blower 2 and the air outlet 14 of the dehumidifier 14, and a tertiary air passage 16 is formed. Dehumidifier 1
Can be moved to the blower 2 side so as to be able to be separated and approached, so that the amount of suction air of the tertiary air 15 can be adjusted. Alternatively, a slide duct may be provided in either the suction port 7 of the blower 2 or the air outlet duct 14 of the dehumidifier 1 to adjust the amount of insertion between them. Reference numeral 9 denotes a secondary air suction port, and reference numeral 10 denotes a damper for adjusting the flow rate of the secondary air 12.

The operation of the embodiment having the above-described structure will be described below. In FIG. 4 schematically showing the entire dry storage apparatus to which the embodiment shown in FIG. 1 is applied, first, a primary air amount G1, a secondary air amount G2, a required air amount G3, and a tertiary air amount
The airflow balance of G4 will be described. The required air amount G3 is determined from the outside air conditions (worst-case conditions such as rainy weather), the maximum moisture content of the grain, and the safe critical airflow ratio under the strictest conditions for dry storage with the maximum storage amount (the maximum stacking height H). As described above, the required air volume G3 is obtained under the strictest conditions for dry storage, and the safety limit air volume ratio is satisfied, thereby guaranteeing the quality of the grain.

First, the dehumidifier 1 is determined so that the air volume G3MIN when the pile height H of the grain 4 is the maximum is equal to the primary air volume G1 + the tertiary air volume G4. That is, the air dehumidified by the dehumidifier 1 and the tertiary air that is not dehumidified are mixed to obtain a mixing ratio between the primary air amount G1 and the tertiary air amount G4 so that a predetermined temperature and humidity are obtained. 1 and the specifications of a commercially available dehumidifier, for example, the processing air flow rate is 100 m ³ / min with a compressor of 10 hp, so that it can be practically adjusted to the condition with the best dehumidification efficiency. Select the dehumidifier 1. Thereby, the primary air amount G1 and the tertiary air amount G4 processed by the dehumidifier 1 are determined. The tertiary air amount G4 is set by moving the dehumidifier 1 to the blower 2 side in FIG. 1 and adjusting the insertion amount of the air outlet 14 of the dehumidifier 1 inserted into the suction port 7 of the blower 2 in FIG. After the adjustment, the dehumidifier 1 is fixed so that the tertiary air amount G4 is always constant. Next, when the stacking height H is the lowest and the required air amount G3 is the maximum, the secondary air amount G2 is determined so that the maximum required air amount G3MAX = the primary air amount G1 + the secondary air amount G2 + the tertiary air amount G4.

This will be described with reference to a simple concrete numerical example which is most easily understood. When the stacking height H is the highest (minimum airflow), the required minimum airflow G3MIN = 300 m ³ / min, and the stacking determined by the performance curve of the blower 2 When the height is the lowest (maximum airflow)
When the maximum required air volume of G3MAX = 500m ³ / min and the air volume to be processed by the dehumidifier (when the stacking height is maximum) G1 = 100m ³ / min, the tertiary air volume G4 is 200m ³ / min, The secondary air amount G2 is at most 200 m ³ / min.

As described above, the tertiary air suction air passage 16 is formed by providing a gap between the dehumidifier 1 and the air suction port 7 of the blower 2, and the tertiary air 15 is sucked. G3MAX should be the sum of the primary air volume G1, the secondary air volume G2, and the tertiary air volume G4.At the minimum required air volume G3MIN, the secondary air volume G2 will be zero and the total air volume of the primary air volume G1 and the tertiary air volume G4 Can be set to the minimum air volume G3MIN, and the processing air volume of the dehumidifier 1 can be made constant.

The air volume balance is as described above, but the actual drying method is as follows. First, it is assumed that the quality of the harvested rice is the required air volume under the most severe conditions for dry storage.
Grain quality is guaranteed by finding G3 and satisfying the safety limit airflow ratio. The pile height H of the harvested rice fluctuates depending on the harvesting state of the harvested rice or the long-term dry storage and the like, and the shipping state of the hulling, and accordingly, the required air volume G3 varies according to the performance curve of the blower 2.

Therefore, by keeping the primary air amount G1 of the primary air 11 to be processed by the dehumidifier 1 and the tertiary air amount G4 sucked from the tertiary air passage 16 constant, the air volume control accompanying the change in the required air volume G3 can be achieved. Since the adjustment may be performed by adjusting the opening of the damper 10 provided in the secondary air suction port 9, the required airflow G3
Can be simplified.

For example, as a specific mode of the air volume control of the required air volume G3, the pressure in the dehumidifier 1 (or the pressure in the dehumidifier 1 according to the change of the discharge pressure of the blower 2 which changes with the change of the pile height H of harvested rice). Since the air flow rate fluctuates, the pressure (or air flow rate) in the dehumidifier 1 is detected, and the opening degree of the damper 10 is controlled so that the pressure or the wind speed in the dehumidifier 1 becomes constant. It becomes possible to control the air volume of the required air volume G3.

Further, since the tertiary air 15 is sucked through the gap formed between the dehumidifier 1 and the air suction port 7 of the blower 2, fluctuations in the pressure (or air flow rate) in the dehumidifier 1 are reduced, In addition, the drift of the primary air 11 in the dehumidifier 1 is reduced, and the control of the required air volume G3 can be further simplified. In addition, by setting the minimum required air volume G3MIN to the total air volume of the primary air volume G1 and the tertiary air volume G4, the secondary air volume G2 can be reduced, and the secondary air suction port 9 can be reduced. As a result, the responsiveness of the control is improved, and the control can be made easier.

As described above, by making the minimum required air volume G3MIN constant as the total air volume of the primary air volume G1 and the tertiary air volume G4, the required air volume G3 can be controlled only by controlling the air volume of the secondary air G2. Therefore, expensive computer control is not required, and since the processing air volume of the dehumidifier 1 is constant, a commercially available dehumidifier can be used.

Further, since the air outlet duct 14 of the dehumidifier 1 is indirectly connected to the suction port 7 of the blower 2 in a state of being inserted, vibration of the blower 2 is not transmitted to the dehumidifier 1, so that the strength of the dehumidifier 1 is reduced. No special consideration is required, and since the connection with the blower 2 is indirect in this way, even if the type of the blower 2 changes, it can be connected and the versatility can be given to the blower. In addition, it becomes possible to use a commercially available dehumidifier also from the viewpoint of the structure.

[0036]

As described above in detail, according to the present invention, the outside air of the drying air obtained by mixing the air dehumidified by the dehumidifier and the outside air is separated into secondary air and tertiary air, and the air in the dehumidifier is removed. Tertiary air is sucked in from a tertiary air suction air passage formed by providing a gap between the outlet and the air suction port of the blower, and a secondary air suction damper is provided in a separately provided secondary air suction port to provide secondary air flow. The total air volume of the primary air dehumidified by the dehumidifier and the tertiary air that is not dehumidified by the dehumidifier so that the total air volume becomes the minimum air volume for drying air, and changes according to the grain height. The required air volume, which varies according to the pile height of the grain, is controlled by adjusting the opening of the damper provided in the secondary air suction port. By adjusting the wind you need It is possible to simplify the control of the air flow rate of the.

Further, since the tertiary air is sucked through the gap formed between the air outlet of the dehumidifier and the air suction port of the blower, the fluctuation of the pressure (or air flow rate) in the dehumidifier is reduced, and The drift of the primary air in the dehumidifier is reduced, and the control of the required air volume can be further simplified. Also, by setting the minimum required air volume to the total air volume of the primary air volume and the tertiary air volume, the secondary air volume can be reduced, thereby making it possible to reduce the secondary air suction port. The responsiveness of the control is improved, and the above control can be made easier.

As described above, since the minimum required air volume is made constant as the total air volume of the primary air volume and the tertiary air volume, the required air volume can be controlled only by controlling the air volume of the secondary air. Since no control is required and the processing air volume of the dehumidifier is constant, a commercially available dehumidifier can be used.

Further, since the air outlet duct of the dehumidifier is inserted in the suction port of the blower and connected indirectly,
Since the vibration of the blower is not transmitted to the dehumidifier, no special consideration on the strength is required, and since the connection with the blower is indirect, it can be connected even if the type of blower changes, and On the other hand, versatility can be provided, and a commercially available dehumidifier can also be used in terms of structure. Further, since the amount of secondary air can be reduced, the suction port of the secondary air can be reduced, and the outer shape of the dehumidifier can be reduced.

As described above, it is possible to use a commercially available dehumidifier, and it is possible to obtain an inexpensive drying device by simplifying the control device, so that the facility use unit price per farmhouse can be reduced. In addition, since the air volume that satisfies the safety critical air volume ratio under the strictest conditions for dry storage can be set, the quality of the grain can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a front view of one embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a right side view of FIG. 1;

FIG. 4 is a schematic diagram showing the whole of a grain drying and storage device to which the drying device in FIG. 1 is applied.

FIG. 5 is a schematic diagram showing the whole of a conventional grain dry storage device.

FIG. 6 is a front view of a conventional drying device.

FIG. 7 is a plan view of FIG. 6;

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Dehumidifier 2 Blower 3 Storage bin 7 Air suction port of blower 9 Secondary air suction port 11 Primary air 12 Secondary air 14 Air outlet of dehumidifier 15 Tertiary air

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B01D 53/26 B01D 53/26 A B02B 1/02 B02B 1/02

Claims (2)

(57) [Claims] 1. The total air volume of the primary air dehumidified by the dehumidifier and the tertiary air not dehumidified by the dehumidifier is made constant so as to be the minimum air volume of the drying air, and the air volume that changes according to the pile height of the grain is controlled. A method for drying cereals, comprising controlling from a minimum air volume to a maximum air volume by adjusting with secondary air. 2. A grain drying apparatus for storing and drying grains by supplying drying air obtained by mixing air dehumidified by a dehumidifier and outside air not dehumidified by a dehumidifier to a grain storage bin by a blower, The outside air is separated into secondary air and tertiary air, and a gap is provided between an air outlet of the dehumidifier and an air suction port of the blower to form a tertiary air suction air passage for sucking the tertiary air. A grain drying apparatus characterized in that a suction port for the secondary air is separately provided and a damper for air volume adjustment is provided in the secondary air suction port.