Grain dryer

Abstract

To suppress the deterioration of grain quality while achieving energy saving when drying edible grain.SOLUTION: A grain dryer (1) comprises a controller (41) that controls actions of a heat source (4), an exhaust fan (7) and circulation mechanisms (11 to 15). The controller (41) activates the exhaust fan (7) and the circulation mechanisms (11 to 15) when an ambient temperature reaches a predetermined set temperature and a moisture value reaches a predetermined set moisture value, and executes an energy saving mode of activating the heat source (4) when the moisture value becomes unable to reach the predetermined set value.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a grain dryer for drying edible grains, feed grains, and the like.

Background Art

[0002] Regarding a grain dryer for drying grains such as rice, wheat, and miscellaneous grains, the technique described in the following Patent Document 1 has been conventionally known.

[0003] Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2014-214890) describes a technique in which when drying edible grains, while circulating the grains trapped in the storage chamber (2), drying hot air is supplied at the drying rate set by the user, and the grains are dried while being circulated until the target moisture value is reached. In Patent Document 1, when drying feed grains, if the moisture value of the trapped grains is less than the set moisture value, the combustion burner (5) is operated to perform combustion drying, and when the moisture value of the grains is greater than or equal to the set moisture value, the process shifts to the combustion process after the ventilation drying process, thereby suppressing the fuel cost of the combustion burner (5) (energy saving) compared to the case of performing the combustion process from the beginning.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] (Problems of the Prior Art) In the configuration shown in Patent Document 1, in the case of drying feed grains, in consideration of energy saving, drying was performed by ventilation until the set moisture value was reached. However, if the same process is simply performed in the case of drying edible grains, problems may occur in the quality of the grains such as a decrease in taste and cracking.

[0006] The technical problem of the present invention is to suppress a decrease in the quality of grains while achieving energy savings in the case of drying edible grains.

Means for Solving the Problems

[0007] In order to solve the above technical problem, the invention according to claim 1 includes a drying chamber (3) capable of accommodating grains, a heat source (4) for supplying heat for drying the grains in the drying chamber (3), an exhaust fan (7) for discharging heat in the drying chamber (3), a circulation mechanism (11 to 15) for circulating the grains, an outside air thermometer (SN2) for detecting the outside air temperature, a moisture meter (18) for detecting the moisture value of the grains in the drying chamber (3), and a control unit (41) for controlling the operations of the heat source (4), the exhaust fan (7), and the circulation mechanism (11 to 15). When the outside air temperature reaches a predetermined set temperature and the moisture value reaches a predetermined set moisture value, the control unit (41) operates the exhaust fan (7) and the circulation mechanism (11 to 15), and when the moisture value no longer reaches the set moisture value, the control unit (41) operates the heat source (4) to execute an energy-saving mode. A drying speed input unit (28) for inputting the speed at which the grains are dried, an energy-saving input unit (26) for inputting the execution of the energy-saving mode, and when the input of the drying speed input unit (28) is not made and the input of the energy-saving input unit (26) is made, the grains are dried at a standard drying speed predetermined when the heat source (4) operates, and when the input of the drying speed input unit (28) is made and the input of the energy-saving input unit (26) is made, the control unit (41) for drying the grains at the drying speed input by the drying speed input unit (28) when the heat source (4) operates A grain dryer (1), characterized by comprising the above.

[0008] The invention according to claim 2 includes an exhaust air thermometer (SN1) for detecting the temperature of the exhaust air discharged by the exhaust fan (7), estimating the temperature of the grains based on the temperature detected by the exhaust air thermometer (SN1), and in the energy-saving mode, when the temperature of the grains reaches the outside air temperature before the heat source (4) operates, the heat source (4) is deactivated, and when the temperature of the grains does not reach the outside air temperature and the moisture value no longer reaches the set moisture value, the heat source (4) is operated. The grain dryer (1) according to claim 1, characterized by comprising the control unit (41).

[0010] Claim 3 The invention according to claim 1, characterized by comprising the control unit (41) that intermittently operates the circulation mechanism (11 to 15) when the moisture value reaches the set moisture value in the energy-saving mode. or 2 The grain dryer (1) according to claim 1.

Advantages of the Invention

[0011] According to the invention described in claim 1, when the outside air temperature reaches a predetermined set temperature and the moisture value reaches a predetermined set moisture value, by operating the exhaust fan (7) and the circulation mechanism (11-15), in the case of drying edible grains, energy conservation can be achieved while suppressing a decrease in the quality of the grains. Further, according to the invention described in claim 1, by drying the grains at the drying speed input by the drying speed input unit (28), the operator can perform drying as intended in consideration of the taste

[0012] According to the invention described in claim 2, in addition to the effects of the invention described in claim 1, when the temperature of the grains reaches the outside air temperature, by deactivating the heat source (4), a decrease in the quality of the grains can be suppressed.

[0014] Claim 3 According to the invention described in, claim 1 or 2 In addition to the effects of the invention described in, by operating the circulation mechanism (11-15) intermittently, it is possible to suppress the occurrence of uneven drying while suppressing damage to the grains.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] Next, with reference to the drawings, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the following examples. In the description of the embodiment, the left and right directions are referred to as left and right, respectively, toward the forward direction of the machine body, and the forward direction is referred to as front and the backward direction is referred to as rear for explanation. In the following description using the drawings, illustrations other than the members necessary for the explanation are appropriately omitted for ease of understanding.

[0017] FIG. 1 is an external view of a grain dryer according to an embodiment of the present invention. FIG. 2 is an explanatory view of the inside of the grain dryer of FIG. 1. FIG. 3 is a cross-sectional view of the drying chamber. FIG. 4 is an explanatory view of the operation panel. FIG. 5 is an explanatory view of the circulation mechanism.

[0018] In FIG. 1, a grain dryer 1 according to an embodiment of the present invention has a box-shaped machine wall 1a. In FIG. 2, inside the machine wall 1a, a storage chamber 2 for storing grains from above is provided. Below the storage chamber 2, a drying chamber 3 for drying grains is provided. In FIGS. 2 and 3, the drying chamber 3 includes a hot air chamber 5 through which hot air generated by a combustion burner 4 as an example of a heat source passes, grain flow-down chambers 6a and 6b on the left and right sides of the hot air chamber 5 where grains flow down, and exhaust chambers 8 arranged on the left and right outer sides of the grain flow-down chambers 6a and 6b. In the exhaust chamber 8, the hot air that has passed through the grain flow-down chamber 6 from the hot air chamber 5 is exhausted by the action of an exhaust fan (discharge fan, discharge means) 7. In FIGS. 1 and 3, the combustion burner 4 is provided in a combustion burner case 9 on the front side of the machine wall 1a. The exhaust fan 7 is arranged on the rear side of the machine wall 1a. Near the exhaust fan 7, an exhaust thermometer SN1 for detecting the temperature of the exhaust air is arranged. A far-infrared radiator 10 is arranged in the hot air chamber 5.

[0019] In FIGS. 2, 3, and 5, rotary valves 11 for feeding out grains are provided at the lower ends of the left and right grain flow-down chambers 6a and 6b. Below the rotary valves 11, lower races 12 for conveying the grains fed out by the rotary valves 11 to the front side are provided. In FIGS. 1 and 5, on the front side of the machine wall 1a, a bucket-type elevator 14 for moving (lifting) upward the grains conveyed by the lower race 12 or the grains charged into the charging hopper 13 is provided. At the upper end of the elevator 14, an upper race 15 is arranged to be connected. The upper race 15 is installed in an upper race trough 16 at the ceiling part of the machine wall 1a. The upper race 15 conveys the grains lifted by the elevator 14 to the storage chamber 2. In the present embodiment, the rotary valve 11, the lower race 12, the elevator 14, and the upper race 15 are referred to as a circulation mechanism for the grains to circulate inside the grain dryer 1.

[0020] In the upper race trough 16, a dust collector 17 for sucking and discharging chaff and the like mixed in the grains conveyed by the upper race 15 is provided. In the middle part of the elevator 14, a moisture meter 18 for taking in the grains falling from the buckets of the elevator 14 and measuring the moisture value is installed. Also, on the machine wall 1a, an outside air thermometer (not shown) for detecting the temperature of the outside air and an outside air humidity meter (not shown) for detecting the humidity of the outside air are installed. At the upper part of the elevator 14, a discharge shutter 19 for discharging the grains outside the machine is installed.

[0021] The rotary valve 11 is configured in a cylindrical shape having a storage chamber 11a for storing grains therein and a take-in port 11b for taking in grains into the storage chamber 11a. That is, it is formed in a C-shaped cross-sectional shape. The rotary valve 11 is configured to be capable of rotating forward and backward by a rotary valve motor 20. The gap between the rotary valve 11 and the grain flow-down chambers 6a and 6b is blocked by a seal member (not shown). Note that the basic operations of the rotary valve 11 and the circulation mechanisms 11 to 15 are conventionally well-known and are described in, for example, Patent Document 1 and Japanese Unexamined Patent Application Publication No. 2017-133792, etc., so detailed description is omitted.

[0022] In FIG. 1, on the front side of the machine wall 1a, an operation panel 21 equipped with an operation switch (an example of an input unit) for operating the grain dryer 1 and the like is arranged. In FIG. 4, the operation switch includes a charging switch 22 for charging grains, a ventilation switch 23 for so-called ventilation operation for driving the exhaust fan 7 and the circulation mechanism, a drying switch 24 for igniting the combustion burner 4 to perform drying operation, a discharge switch 25 for discharge operation for discharging the grains in the storage chamber 2 to the outside of the machine, and an energy-saving operation switch (an example of an energy-saving input unit) 26 for operating in the energy-saving mode. Further, on the operation panel 21, a grain setting switch 27 for selecting the variety of grains (edible rice, feed rice, wheat, etc.) charged into the storage chamber 2, a drying speed selection switch (an example of a drying speed input unit) 28 for selecting the drying speed, a moisture setting switch 29 for setting the target moisture value, a charging amount setting switch 30 for setting the charging amount, and a stop switch 31 are provided. Further, on the operation panel 21, a drying operation display screen (an example of a display unit) 32 for displaying information on the drying operation such as the moisture value and the remaining drying operation time, and a setting display screen (an example of a display unit) 33 for displaying the set charging amount or the set moisture value are provided. Further, inside the operation panel 21, a control unit (not shown) for controlling the operation is built in.

[0023] (Description of the control unit of the embodiment) FIG. 6 is a functional block diagram for explaining the functions of the control unit of the grain dryer according to the embodiment. In FIG. 6, the control unit 41 has an input / output interface I / O for inputting and outputting signals to and from the outside. Further, the control unit 41 has a ROM: read-only memory in which programs and information for performing necessary processing are stored. Further, the control unit 41 has a RAM: random access memory for temporarily storing necessary data. Further, the control unit 41 has a CPU: central processing unit for performing processing according to the programs stored in the ROM and the like. Therefore, the control unit 41 is constituted by a so-called microcomputer (an example of a computer device), and various functions can be realized by executing the programs stored in the ROM and the like.

[0024] (Function of the control unit) The control unit 41 receives input signals from signal output elements such as the exhaust air thermometer SN1, the moisture meter 18, the outside air thermometer SN2, the outside air humidity meter SN3, and other sensors (not shown). The control unit 41 outputs control signals to each control element such as the combustion burner 4, the exhaust fan 7, and the rotary valve motor 20 of the circulation mechanisms 11 to 15. The control unit 41 of the embodiment has the following functions.

[0025] The outside air temperature detection means 42 detects the temperature of the outside air based on the input signal from the outside air thermometer SN2. The outside air humidity detection means 43 detects the humidity of the outside air based on the input signal from the outside air humidity meter SN3. The moisture detection means 44 detects the moisture value of the grains based on the input signal from the moisture meter 18.

[0026] The exhaust air temperature detection means 45 detects the temperature of the exhaust air based on the input signal from the exhaust air thermometer SN1. The grain temperature estimation means 46 estimates the temperature of the flowing grains based on the temperature of the exhaust air. In the embodiment, the relationship (function, look-up table, etc.) between the temperature of the exhaust air and the temperature of the grains has been derived in advance by experiments or the like. Therefore, the temperature of the grains can be derived (estimated) from this relationship and the detected exhaust air temperature.

[0027] The combustion burner control means 47 controls the operation (ignition) and stop of the combustion burner 4. The combustion burner control means 47 of the embodiment activates the combustion burner 4 when the input of the drying switch 24 is received. The exhaust fan control means 48 controls the operation (rotation) and stop of the exhaust fan 7. The exhaust fan control means 48 of the embodiment activates the exhaust fan 7 when the inputs of the ventilation switch 23 and the drying switch 24 are received.

[0028] The circulation control means 49 controls the operation and stop of the circulation mechanisms 11 to 15. When the ventilation switch 23, the drying switch 24, or the discharge switch 25 is input, the circulation control means 49 in the embodiment activates the circulation mechanisms 11 to 15. The energy-saving mode control means 50 controls the grain dryer 1 in the energy-saving mode. When the energy-saving operation switch 26 is input, the energy-saving mode control means 50 in the embodiment controls the combustion burner 4, the exhaust fan 7, and the circulation mechanisms 11 to 15 via the combustion burner control means 47, the exhaust fan control means 48, and the circulation control means 49 to operate the grain dryer 1 in the energy-saving mode.

[0029] Specifically, when the energy-saving operation switch 26 is input with the grain filled inside the grain dryer 1 and the filling amount set, the energy-saving mode control means 50 in the embodiment activates the exhaust fan 7 and the circulation mechanisms 11 to 15 when the outside air temperature reaches a predetermined set temperature (for example, 20°C) and the moisture value reaches a predetermined set moisture value (for example, 28%). When the moisture value no longer reaches the set moisture value, the combustion burner 4 is activated. That is, when the outside air temperature is equal to or higher than the set temperature and the moisture value is equal to or higher than the set moisture value, a ventilation and circulation operation is performed in which the combustion burner 4 is stopped and the exhaust fan 7 and the circulation mechanisms 11 to 15 are activated. When the moisture value becomes less than the set moisture value, a drying operation is performed in which the exhaust fan 7 and the circulation mechanisms 11 to 15 are activated and then the combustion burner 4 is also activated. When the moisture value of the grain reaches the target moisture value (for example, 14%), the drying operation ends. That is, the combustion burner 4, the exhaust fan 7, and the circulation mechanisms 11 to 15 are stopped. After the drying operation ends, it is also possible to perform a resting drying operation in which all devices are maintained in a stopped state for a predetermined time (for example, 2 hours) to condition the grain.

[0030] Note that when the energy-saving mode control means 50 of the embodiment executes the ventilation circulation operation for a predetermined time (e.g., 2 hours) when the outside air temperature is equal to or higher than the set temperature and the moisture value is equal to or higher than the set moisture value, it stops the circulation mechanisms 11 to 15 and operates only the exhaust fan 7 for a predetermined time (e.g., 1 hour), and operates so as to alternately repeat the ventilation circulation operation and the ventilation operation. That is, the circulation mechanisms 11 to 15 operate intermittently, and the operation and stop (ventilation circulation operation and ventilation operation) are alternately switched.

[0031] Further, in the energy-saving mode control means 50 of the embodiment, before the combustion burner 4 operates, when the temperature of the grains (grain temperature) reaches the outside air temperature, the combustion burner 4 is deactivated (maintaining the stopped state), and when the grain temperature does not reach the outside air temperature and the moisture value no longer reaches the set moisture value, the combustion burner 4 is activated. That is, during the ventilation circulation operation or the ventilation operation, even if the moisture value becomes less than the set moisture value, if the grain temperature is equal to or higher than the outside air temperature, the combustion burner 4 is not activated. Note that after shifting to the drying operation, even if the grain temperature becomes equal to or higher than the outside air temperature, the combustion burner 4 is not stopped until the drying operation ends.

[0032] Furthermore, in the energy-saving mode control means 50 of the embodiment, when performing the ventilation circulation operation, the circulation mechanisms 11 to 15 are controlled so that the drying rate of the grains becomes higher than a predetermined standard drying rate. Note that when the rotary valve 11 of the embodiment conveys grains, it conveys a predetermined amount of grains in one rotation, and basically, after one rotation, it stops rotating for a predetermined stop period to control the conveyance amount per unit time. Here, when the drying rate is increased and the rotary valve 11 is continuously rotated, if the moisture content of the grains is high, it is likely to become clogged on the downstream side. Therefore, when increasing the conveyance speed, it is desirable to adjust the grain conveyance speed by shortening the stop period without continuously rotating the rotary valve 11.

[0033] When shifting to the drying operation, if the drying speed is set with the drying speed selection switch 28 before the input of the energy-saving operation switch 26, the circulation mechanisms 11 to 15 are controlled at the set drying speed to perform the drying operation. If the drying speed is not set, the drying operation is performed by controlling the circulation mechanisms 11 to 15 at the standard drying speed. In the embodiment, when controlling the drying speed, the case of changing the grain conveyance speed (circulation speed) of the circulation mechanisms 11 to 15 is exemplified, but it is not limited thereto. For example, the drying speed can be adjusted by setting the combustion temperature of the combustion burner 4 to a high temperature or a low temperature, or by increasing or decreasing the exhaust air volume of the exhaust fan 7, or by changing two or more of the combustion temperature, the grain conveyance speed, and the exhaust air volume.

[0034] (Explanation of the flowchart) FIG. 7 is an explanatory diagram showing the flow of the energy-saving mode process of the embodiment. The processing of each step ST in the flowchart of FIG. 7 is performed according to a program stored in the control unit 41 of the grain dryer 1. This processing is executed in parallel with other various processes of the grain dryer 1.

[0035] The flowchart shown in FIG. 7 is started when the power of the grain dryer 1 is turned on. In ST1 of FIG. 7, it is determined whether or not the input of the energy-saving operation switch 26 has been made. If yes (Y), the process proceeds to ST2; if no (N), ST1 is repeated. In ST2, it is determined whether or not the outside air temperature is equal to or higher than the set temperature. If yes (Y), the process proceeds to ST3; if no (N), the process proceeds to ST13. In ST3, it is determined whether or not the moisture value of the grain is equal to or higher than the set moisture value. If yes (Y), the process proceeds to ST4; if no (N), the process proceeds to ST13. In ST4, the exhaust fan 7 is operated, and a ventilation circulation operation of operating the circulation mechanisms 11 to 15 at high speed is started. Then, the process proceeds to ST5.

[0036] In ST5, it is determined whether the moisture content of the grains has become less than the set moisture content. If yes (Y), proceed to ST6; if no (N), proceed to ST7. In ST6, it is determined whether the grain temperature is less than or equal to the outside air temperature. If yes (Y), proceed to ST13; if no (N), return to ST5. In ST7, it is determined whether the operation time of the ventilation circulation operation has reached a predetermined time or more. If yes (Y), proceed to ST8; if no (N), return to ST5. In ST8, switch to a ventilation operation in which only the exhaust fan 7 is operated. Then, proceed to ST9.

[0037] In ST9, it is determined whether the moisture content of the grains has become less than the set moisture content. If yes (Y), proceed to ST10; if no (N), proceed to ST11. In ST10, it is determined whether the grain temperature is less than or equal to the outside air temperature. If yes (Y), proceed to ST13; if no (N), return to ST9. In ST11, it is determined whether the operation time of the ventilation circulation operation has reached a predetermined time or more. If yes (Y), proceed to ST12; if no (N), return to ST9. In ST12, switch to the ventilation circulation operation. Then, proceed to ST5.

[0038] In ST13, it is determined whether the drying speed is set by the drying speed selection switch 28. If yes (Y), proceed to ST14; if no (N), proceed to ST15. In ST14, set the set drying speed as the drying speed in the drying operation. Then, proceed to ST16. In ST15, set the standard drying speed as the drying speed in the drying operation. Then, proceed to ST16.

[0039] In ST16, ignite the combustion burner 4, operate the exhaust fan 7, and start a drying operation in which the circulation mechanisms 11 to 15 are operated at the drying speed. Then, proceed to ST17. In ST17, it is determined whether the moisture content has reached or fallen below the target moisture content. If yes (Y), proceed to ST18; if no (N), repeat ST17. In ST18, end the drying operation and return to ST1.

[0040] (Operation of the Embodiment) In the grain dryer 1 of the embodiment having the above configuration, when drying grains, if the outside air temperature is equal to or higher than the set temperature and the moisture content is equal to or higher than the set moisture content, a ventilation circulation operation is performed without the combustion burner 4 operating. That is, in a situation where the outside air temperature is high and the moisture content contained in the grains is high, drying can proceed sufficiently with ventilation alone, so drying is performed until the moisture content becomes less than the set moisture content without using the combustion burner 4. If the combustion burner 4 is used in a situation where the outside air temperature is high, the grain temperature is likely to rise, and the taste of grains, especially edible grains, is likely to deteriorate. Therefore, in the embodiment, when the outside air temperature is equal to or higher than the set temperature and the moisture content is equal to or higher than the set moisture content, drying is started initially without using the combustion burner 4. In the case of drying edible grains, energy conservation is achieved while suppressing a decrease in the quality of the grains.

[0041] In addition, in a situation where drying does not easily proceed with ventilation alone as in the case of a low outside air temperature and the grain temperature does not easily rise much, or in a situation where drying does not easily proceed with ventilation alone when the initial moisture content of the grains is low, the grains can be dried by a drying operation using the combustion burner 4. In the embodiment, it is determined whether to perform the ventilation circulation operation based on the outside air temperature and the moisture content of the grains, but it is not limited to this. When the outside air humidity is low, drying easily proceeds with ventilation alone, so it is also possible to perform the ventilation circulation operation when the outside air humidity is low. Conversely, when the outside air humidity is too high (for example, 90% RH or higher), it is also possible to shift to the drying operation even if the moisture content of the grains is high.

[0042] Also, in the grain dryer 1 of the embodiment, during the ventilation circulation operation or the ventilation operation, even if the grain moisture value becomes less than the set moisture value, if the grain temperature is equal to or higher than the outside air temperature, the dryer does not shift to the drying operation. Grains respire even after harvest, and the grain temperature may naturally become higher than the outside air temperature. If the dryer shifts to the drying operation when the grain temperature is high, the grain temperature during the drying operation may become too high and the taste may deteriorate. Therefore, when the grain temperature is high, the grain temperature is lowered by ventilation. Thus, a decrease in taste is suppressed. Furthermore, in the grain dryer 1 of the embodiment, the grain temperature is estimated from the exhaust air thermometer SN1. Although a thermometer (grain thermometer) that directly detects the temperature of the grains can also be used, the grain thermometer can only measure the temperature of the grains at a specific location. Therefore, if the amount of grains loaded increases and there are variations in the grain temperature in the storage chamber 2 and the drying chamber 3, there is a risk that the dryer will shift to the drying operation with a large amount of grains having a high grain temperature. In contrast, with the exhaust air thermometer SN1, the average temperature of the drying chamber 3 is easily measured, and the influence of variations is easily suppressed.

[0043] Also, in the grain dryer 1 of the embodiment, when the drying speed is set by the operator's input, the drying operation is performed at the set drying speed. Therefore, in addition to energy saving, the drying operation can be performed at the drying speed intended by the operator considering taste and the like. Even if the operator forgets to set the drying speed, the drying operation can be performed at the standard drying speed.

[0044] Furthermore, in the grain dryer 1 of the embodiment, the ventilation circulation operation and the ventilation operation can be switched. If only the ventilation circulation operation is performed, when the grains are conveyed by the circulation mechanisms 11 to 15, the grains may be rubbed and significantly damaged. Conversely, if only the ventilation operation is performed, the grains do not flow in the storage chamber 2 and the drying chamber 3, and there is a risk that local drying may progress or local drying may hardly occur. That is, non-uniform drying is likely to occur. In contrast, in the embodiment, by using both the ventilation operation without conveying the grains and the ventilation circulation operation with the flow of the grains, it is possible to suppress damage to the grains and also suppress the occurrence of non-uniform drying. If damage to the grains and non-uniform drying are acceptable, it is also possible to use only the ventilation circulation operation or only the ventilation operation.

[0045] In the foregoing embodiments, although the case where grains are circulated at high speed during the ventilation circulation operation in the energy-saving mode has been exemplified, the present invention is not limited thereto. For example, in the case of "paddy (rice)", during the ventilation circulation operation, that is, when the moisture value is high, by increasing the circulation speed, it becomes difficult for uneven drying to occur throughout the storage chamber 2 and the drying chamber 3. And in the case of "paddy (rice)", during the drying operation, that is, when the moisture value has decreased to a certain extent, by reducing the circulation speed to the standard drying speed, it becomes easier to temper (diffuse and homogenize the moisture inside the grain). On the other hand, in the case of "wheat", when the moisture value is high, there is a risk that the weight becomes heavy and it cannot be conveyed by the circulation mechanisms 11 to 15, and it is possible to reduce the circulation speed (conveying speed) to suppress the load on the motor. And in the drying operation of "wheat", since the moisture value has become relatively low, it is possible to increase the circulation speed to suppress uneven drying throughout the storage chamber 2 and the drying chamber 3. In particular, when drying wheat harvested from a plurality of fields at once, since the moisture values of the wheat may be different for each field, it is also possible to suppress the unevenness of the moisture values by increasing the circulation speed and mixing the wheat from a plurality of fields. Therefore, it is possible to change the conveying speed of the grains during the ventilation circulation operation or the drying operation according to the type of the grains. Also, in the case of the aforementioned wheat, it is also possible to detect the load on the motor with a sensor and control it to increase the conveying speed when the load drops below a predetermined value. At this time, also, when there are grains for which rapid drying is not preferable, it is desirable to change the combustion temperature during the drying operation for each type of grain.

[0046] The specific numerical values exemplified in the above embodiments can be appropriately changed according to the design, specifications, etc. Also, although the configuration provided with the energy-saving operation switch 26 has been exemplified, the present invention is not limited thereto. For example, it is also possible to adopt a configuration in which the energy-saving operation switch 26 is not provided, and it is determined that an input for selecting the energy-saving mode is made when, for example, the ventilation switch 23 and the drying switch 24 are pressed simultaneously.

Explanation of Reference Numerals

[0047] 1…Grain dryer, 3…Drying chamber, 4…Heat source, 7…Exhaust fan, 11~15…Circulation mechanism, 18…Moisture meter, 26…Energy-saving input section, 28…Drying speed input section, 41…Control unit, SN1…Exhaust air thermometer, SN2…Outside air thermometer.

Claims

1. A drying chamber (3) capable of accommodating grains, A heat source (4) that supplies heat for drying the grains in the drying chamber (3), An exhaust fan (7) that discharges heat in the drying chamber (3), A circulation mechanism (11 - 15) for circulating the grains, An outside air thermometer (SN2) for detecting the outside air temperature, A moisture meter (18) for detecting the moisture value of the grains in the drying chamber (3), A control unit (41) for controlling the operations of the heat source (4), the exhaust fan (7), and the circulation mechanism (11 - 15), which, when the outside air temperature reaches a predetermined set temperature and the moisture value reaches a predetermined set moisture value, operates the exhaust fan (7) and the circulation mechanism (11 - 15), and when the moisture value no longer reaches the set moisture value, operates the heat source (4) to execute an energy - saving mode; A drying speed input unit (28) for inputting the drying speed of the grains, An energy - saving input unit (26) for inputting the execution of the energy - saving mode, The control unit (41) which, when no input is made to the drying speed input unit (28) and an input is made to the energy - saving input unit (26), dries the grains at a predetermined standard drying speed when the heat source (4) operates, and when an input is made to the drying speed input unit (28) and an input is made to the energy - saving input unit (26), dries the grains at the drying speed input by the drying speed input unit (28) when the heat source (4) operates; A grain dryer (1), characterized by comprising the above components.

2. An exhaust air thermometer (SN1) for detecting the temperature of the exhaust air discharged by the exhaust fan (7), Based on the temperature detected by the exhaust air thermometer (SN1), estimates the temperature of the grains, and in the energy - saving mode, before the heat source (4) operates, if the temperature of the grains reaches the outside air temperature, the heat source (4) is deactivated, and if the temperature of the grains does not reach the outside air temperature and the moisture value no longer reaches the set moisture value, the heat source (4) is activated; the control unit (41); The grain dryer (1) according to Claim 1, characterized by comprising the above components.

3. In the energy - saving mode, when the moisture value reaches the set moisture value, the control unit (41) that intermittently operates the circulation mechanism (11 - 15); The grain dryer (1) according to Claim 1 or 2, characterized by comprising the above components.

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