Grain dryer

Abstract

To realize energy saving when drying grain.SOLUTION: The grain dryer comprises a drying chamber 3 capable of storing grain, a heat source 4 feeding heat for drying the grain present in the drying chamber, a discharge fan 7 discharging heat present in the drying chamber, a circulation mechanism 11 circulating grain, and a controller controlling the actions of the heat source, the discharge fan and the circulation mechanism. The grain dryer is characterized in that the amount of grain conveyed per unit time by the circulation mechanism when the discharge fan and the circulation mechanism are in action with the heat source in a stopped state, is controlled to be more than the amount of grain conveyed per unit time by the circulation mechanism when the discharge fan and the circulation mechanism are in action with the heat source in an acting state.SELECTED DRAWING: Figure 3

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 technology described in the following Patent Document 1 has been conventionally known.

[0003] In Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2014-214890), 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 to the target moisture value. The technology is described. 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 proceeds to the combustion process after the ventilation drying process, compared with the case of performing the combustion process from the beginning, a technology for suppressing the fuel cost of the combustion burner (5) (energy saving) is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technical problem of the present invention is to achieve energy saving in the case of drying grains.

Means for Solving the Problems

[0006] In order to solve the above technical problem, the invention according to claim 1 is a drying chamber (3) capable of accommodating grains, and A heat source (4) for supplying heat for drying grains in the drying chamber (3), An exhaust fan (7) for exhausting heat in the drying chamber (3), A circulation mechanism (11 - 15) for circulating grains, Comprising a control unit (41) for controlling the operations of the heat source (4), the exhaust fan (7), and the circulation mechanism (11 - 15), The exhaust fan (7) and the circulation mechanism (11 - 15) operate in a state where the heat source (4) has stopped, When the exhaust fan (7) and the circulation mechanism (11 - 15) are operating in a state where the heat source (4) has stopped, the conveyance amount per unit time of the circulation mechanism (11 - 15) is controlled to be more than the conveyance amount per unit time of the circulation mechanism (11 - 15) when the heat source (4) is operating and the exhaust fan (7) and the circulation mechanism (11 - 15) are operating. A grain dryer characterized by this is provided.

[0007] The invention according to claim 2, A drying chamber (3) capable of accommodating grains, A heat source (4) for supplying heat for drying grains in the drying chamber (3), An exhaust fan (7) for exhausting heat in the drying chamber (3), A circulation mechanism (11 - 15) for circulating grains, An outside air thermometer (SN2) for detecting the outside air temperature, A moisture meter (18) for detecting the moisture value of grains in the drying chamber (3), Comprising a control unit (41) for controlling the operations of the heat source (4), the exhaust fan (7), and the circulation mechanism (11 - 15), When the outside air temperature is equal to or higher than a predetermined set temperature and the moisture value is equal to or higher than the set moisture value, the exhaust fan (7) and the circulation mechanism (11 - 15) operate in a state where the heat source (4) has stopped, and when the moisture value becomes lower than the set moisture value, an energy - saving mode is executed in which the heat source (4) is operated, When in the energy - saving mode, the conveyance amount per unit time of the circulation mechanism (11 - 15) is controlled to be more when the heat source (4) is stopped and the exhaust fan (7) and the circulation mechanism (11 - 15) are operated than when the heat source (4) is operated. A grain dryer characterized by this is provided.

Advantages of the Invention

[0008] According to the present invention, energy-saving drying can be realized.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0010] Next, examples, which are specific examples of embodiments of the present invention, will be described with reference to the drawings. However, the present invention is not limited to the following examples.

[0011] 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.

[0012] In the following description using the drawings, illustrations other than the members necessary for explanation are appropriately omitted for ease of understanding.

[0013] FIG. 1 is an external view of a grain dryer according to an embodiment of the present invention.

[0014] FIG. 2 is an explanatory view of the inside of the grain dryer of FIG. 1.

[0015] Figure 3 is a cross-sectional view of the drying chamber.

[0016] Figure 4 is an explanatory diagram of the operation panel.

[0017] Figure 5 is an explanatory diagram of the circulation mechanism.

[0018] In Fig. 1, the grain dryer 1 according to the 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.

[0019] 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 back 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.

[0020] A far-infrared radiator 10 is arranged in the hot air chamber 5.

[0021] 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 valve 11, a lower raceway 12 for conveying the grains fed out by the rotary valve 11 to the front side is provided.

[0022] In FIGS. 1 and 5, on the front side of the machine wall 1a, there is provided a bucket-type elevator 14 that moves (winnows) upward the grains conveyed by the lower race 12 or the grains charged into the charging hopper 13. At the upper end of the elevator 14, the upper race 15 is arranged to be connected. The upper race 15 is installed inside the upper race gutter 16 at the ceiling part of the machine wall 1a. The upper race 15 conveys the grains winnowed by the elevator 14 to the storage chamber 2.

[0023] In this 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.

[0024] In the upper race gutter 16, there is provided a dust collector 17 that sucks and discharges chaff and the like mixed in the grains conveyed by the upper race 15.

[0025] In the middle part of the elevator 14, there is installed a moisture meter 18 that takes in the grains falling from the buckets of the elevator 14 and measures the moisture value. Also, on the machine wall 1a, there are installed an outside air thermometer (not shown) for detecting the temperature of the outside air and an outside air hygrometer (not shown) for detecting the humidity of the outside air.

[0026] At the upper part of the elevator 14, there is installed a discharge shutter 19 for discharging the grains outside the machine.

[0027] The rotary valve 11 is configured in a cylindrical shape having a storage chamber 11a for storing grains inside 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 forward and reverse rotation by a rotary valve motor 20. The gap between the rotary valve 11 and the grain flow-down chambers 6a, 6b is blocked by a seal member (not shown).

[0028] Note that the basic operations of the rotary valve 11 and the circulation mechanism 11 to 15 are conventionally well-known and are described, for example, in Patent Document 1 and Japanese Unexamined Patent Application Publication No. 2017 - 133792, etc., so detailed description is omitted.

[0029] In Fig. 1, 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 on the front side of the machine wall 1a. 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.

[0030] Further, on the operation panel 21, there are provided a grain setting switch 27 for selecting the variety of the 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.

[0031] Further, on the operation panel 21, there are provided 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.

[0032] Further, inside the operation panel 21, a control unit (not shown) for controlling the operation is built in.

[0033] (Explanation of the control unit in the embodiment) Fig. 6 is a functional block diagram for explaining the functions of the control unit of the grain dryer in the embodiment.

[0034] In FIG. 6, the control unit 41 has an input / output interface I / O for inputting and outputting signals to and from the outside. The control unit 41 also has a ROM (Read Only Memory) in which programs and information for performing necessary processes are stored. The control unit 41 also has a RAM (Random Access Memory) for temporarily storing necessary data. The control unit 41 also has a CPU (Central Processing Unit) for performing processes 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.

[0035] (Function of the control unit) The control unit 41 receives input signals from signal output elements such as an exhaust air thermometer SN1, a moisture meter 18, an outside air thermometer SN2, an outside air humidity meter SN3, and other sensors (not shown).

[0036] The control unit 41 outputs control signals to each control element such as a combustion burner 4, an exhaust fan 7, and a rotary valve motor 20 of the circulation mechanisms 11 to 15.

[0037] The control unit 41 of the embodiment has the following functions.

[0038] 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.

[0039] 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.

[0040] The moisture detection means 44 detects the moisture value of the grains based on the input signal from the moisture meter 18.

[0041] 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.

[0042] 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 (such as a function or a lookup table) between the temperature of the exhaust air and the temperature of the grains has been derived in advance through experiments or the like. Therefore, the temperature of the grains can be derived (estimated) from this relationship and the detected exhaust air temperature.

[0043] The combustion burner control means 47 controls the operation (ignition) and stop of the combustion burner 4. The combustion burner control means 47 in the embodiment activates the combustion burner 4 when the input of the drying switch 24 is received.

[0044] The exhaust fan control means 48 controls the operation (rotation) and stop of the exhaust fan 7. The exhaust fan control means 48 in the embodiment activates the exhaust fan 7 when the input of the ventilation switch 23 or the drying switch 24 is received.

[0045] The circulation control means 49 controls the operation and stop of the circulation mechanisms 11 to 15. The circulation control means 49 in the embodiment activates the circulation mechanisms 11 to 15 when the input of the ventilation switch 23, the drying switch 24, or the discharge switch 25 is received.

[0046] The energy-saving mode control means 50 controls the grain dryer 1 in the energy-saving mode. 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 when the input of the energy-saving operation switch 26 is received, and operates the grain dryer 1 in the energy-saving mode.

[0047] Specifically, when grains are jammed inside the grain dryer 1 and the input of the energy-saving operation switch 26 is made with the setting of the jamming amount, when the outside air temperature reaches a preset temperature (for example, 20°C) and the moisture value reaches a preset moisture value (for example, 28%), the exhaust fan 7 and the circulation mechanisms 11 to 15 are operated, and when the moisture value no longer reaches the set moisture value, the combustion burner 4 is operated. 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 executed in which the exhaust fan 7 and the circulation mechanisms 11 to 15 are operated with the combustion burner 4 stopped, and when the moisture value becomes less than the set moisture value, a drying operation is executed in which the exhaust fan 7 and the circulation mechanisms 11 to 15 are operated and then the combustion burner 4 is also operated.

[0048] And when the moisture value of the grains 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. Note that after the drying operation ends, it is also possible to perform a rest drying operation in which all devices are maintained in a stopped state for a predetermined time (for example, 2 hours) to condition (temper) the grains.

[0049] In addition, 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, if the energy-saving mode control means 50 of the embodiment executes the ventilation and circulation operation for a predetermined time (for example, 2 hours), it executes a ventilation operation in which the circulation mechanisms 11 to 15 are stopped and only the exhaust fan 7 is operated for a predetermined time (for example, 1 hour), and operates so as to alternately repeat the ventilation and circulation operation and the ventilation operation. That is, the circulation mechanisms 11 to 15 operate intermittently, and the operation and stop (ventilation and circulation operation and ventilation operation) are alternately switched.

[0050] Also, in the energy-saving mode control means 50 of the embodiment, before the combustion burner 4 operates, if 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.

[0051] 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.

[0052] Note that when the rotary valve 11 of the embodiment conveys grains, it conveys a predetermined amount of grains in one rotation. Basically, after one rotation, the rotation is stopped 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 clog on the downstream side. Therefore, when increasing the conveyance speed, it is desirable to adjust the conveyance speed of the grains by shortening the stop period without continuously rotating the rotary valve 11.

[0053] Also, when shifting to the drying operation, if the drying speed is set by 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. Note that when the drying speed is not set, the drying operation is performed by controlling the circulation mechanisms 11 to 15 at the standard drying speed.

[0054] 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 the present invention is not limited thereto. For example, the drying speed may 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.

[0055] (Description of the flowchart) FIG. 7 is an explanatory diagram showing the flow of the energy-saving mode process of the embodiment.

[0056] 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. Further, this processing is executed in parallel with various other processes of the grain dryer 1.

[0057] The flowchart shown in FIG. 7 is started when the power of the grain dryer 1 is turned on.

[0058] In ST1 of FIG. 7, it is determined whether the input of the energy-saving operation switch 26 has been received. If yes (Y), the process proceeds to ST2, and if no (N), ST1 is repeated.

[0059] In ST2, it is determined whether the outside air temperature is equal to or higher than the set temperature. If yes (Y), the process proceeds to ST3, and if no (N), the process proceeds to ST13.

[0060] In ST3, it is determined whether the moisture value of the grain is equal to or higher than the set moisture value. If yes (Y), the process proceeds to ST4, and if no (N), the process proceeds to ST13.

[0061] In ST4, the exhaust fan 7 is operated, and a ventilation circulation operation for operating the circulation mechanisms 11 to 15 at a high speed is started. Then, the process proceeds to ST5.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] In ST8, switch to the ventilation operation that activates only the exhaust fan 7. Then, proceed to ST9.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] In ST12, switch to the ventilation circulation operation. Then, proceed to ST5.

[0070] 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.

[0071] In ST14, set the set drying speed as the drying speed in the drying operation. Then, proceed to ST16.

[0072] In ST15, set the standard drying speed to the drying speed during the drying operation. Then, proceed to ST16.

[0073] In ST16, ignite the combustion burner 4, operate the exhaust fan 7, and start the drying operation in which the circulation mechanisms 11 to 15 are operated at the drying speed. Then, proceed to ST17.

[0074] In ST17, determine whether the moisture value has become equal to or less than the target moisture value. If yes (Y), proceed to ST18; if no (N), repeat ST17.

[0075] In ST18, end the drying operation and return to ST1.

[0076] (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 value is equal to or higher than the set moisture value, a ventilation circulation operation in which the combustion burner 4 does not operate is performed. That is, in a situation where the outside air temperature is high and the moisture contained in the grains is large, drying proceeds sufficiently only by ventilation, so drying is performed until the moisture value becomes less than the set moisture value 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 tends to rise, and the taste of the grains, particularly edible grains, tends to deteriorate. Therefore, in the embodiment, 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, drying is started initially without using the combustion burner 4, and in the case of drying edible grains, energy conservation is realized while suppressing a decrease in the quality of the grains.

[0077] Note that in a situation where drying is difficult to proceed only by ventilation as in the case of a low outside air temperature and the grain temperature does not rise so much, or in a situation where drying is difficult to proceed only by ventilation when the moisture value of the grains is low from the beginning, the grains can be dried by a drying operation using the combustion burner 4.

[0078] In the embodiment, it is determined whether to perform the ventilation circulation operation based on the outside air temperature and the moisture value of the grains, but it is not limited to this. When the outside air humidity is low, drying tends to proceed only by ventilation, 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 more), it is also possible to shift to the drying operation even if the moisture value of the grains is high.

[0079] 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 drying operation is not shifted to. Grains respire even after harvesting, and the grain temperature may naturally become higher than the outside air temperature. And if the drying operation is shifted to in a state where the grain temperature is high, there is a risk that the grain temperature during the drying operation becomes too high and the taste deteriorates. Therefore, in a state where the grain temperature is high, the grain temperature is lowered by ventilation. Thus, the deterioration of the taste is suppressed.

[0080] 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, when the amount of grains charged increases and there is unevenness in the grain temperature in the storage chamber 2 and the drying chamber 3, there is a risk that the drying operation will be shifted to in a state where there are many grains with a high grain temperature. On the other hand, with the exhaust air thermometer SN1, the average temperature of the drying chamber 3 is easily measured, and the influence of unevenness is easily suppressed.

[0081] 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 the taste and the like. Even if the setting of the drying speed is forgotten, the drying operation can be performed at the standard drying speed.

[0082] 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 executed, 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 executed, the grains do not flow in the storage chamber 2 or the drying chamber 3, and there may be a situation where drying progresses locally or hardly at all locally, that is, uneven drying is likely to occur. In contrast, in the embodiment, by using both the ventilation operation without grain conveyance and the ventilation circulation operation with grain flow, it is possible to suppress grain damage and also suppress the occurrence of uneven drying. When grain damage and uneven drying are acceptable, it is also possible to perform only the ventilation circulation operation or only the ventilation operation.

[0083] In the above-described embodiment, in the energy-saving mode, the case of circulating grains at a high speed during the ventilation circulation operation was exemplified, but it is not limited to this. 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, uneven drying throughout the storage chamber 2 and the drying chamber 3 is less likely to occur. 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 equalize the moisture inside the grains). In contrast, 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 decreased to a certain extent, 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 differ from field to 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.

[0084] Therefore, it is possible to change the conveyance speed of the grains during the ventilation circulation operation or the drying operation according to the type of grains. Also, in the case of the above-mentioned wheat, it is also possible to detect the load of the motor with a sensor and control it to increase the conveyance speed when the load drops below a predetermined value.

[0085] 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.

[0086] The specific numerical values exemplified in the above embodiment can be appropriately changed according to the design, specifications, etc.

[0087] Also, although the configuration provided with the energy-saving operation switch 26 has been exemplified, it 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, for example, when the ventilation switch 23 and the drying switch 24 are pressed simultaneously, it is determined that an input for selecting the energy-saving mode has been made.

Explanation of Signs

[0088] 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 section, 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) that circulates the grains, Comprising a control unit (41) that controls the operations of the heat source (4), the exhaust fan (7), and the circulation mechanism (11 - 15), The exhaust fan (7) and the circulation mechanism (11 - 15) operate in a state where the heat source (4) has stopped, The conveyance amount per unit time of the circulation mechanism (11 - 15) when the exhaust fan (7) and the circulation mechanism (11 - 15) are operating in a state where the heat source (4) has stopped is controlled to be more than the conveyance amount per unit time of the circulation mechanism (11 - 15) when the exhaust fan (7) and the circulation mechanism (11 - 15) are operating in a state where the heat source (4) is operating. A grain dryer characterized by this.

2. 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) that circulates the grains, An outside air thermometer (SN2) that detects the outside air temperature, A moisture meter (18) that detects the moisture value of the grains in the drying chamber (3), Comprising a control unit (41) that controls the operations of the heat source (4), the exhaust fan (7), and the circulation mechanism (11 - 15), When the outside air temperature is equal to or higher than a predetermined set temperature and the moisture value is equal to or higher than the set moisture value, the exhaust fan (7) and the circulation mechanism (11 - 15) operate in a state where the heat source (4) has stopped, and when the moisture value becomes lower than the set moisture value, an energy - saving mode is executed in which the heat source (4) is operated. The conveyance amount per unit time of the circulation mechanism (11 - 15) in the energy - saving mode is controlled to be more when the exhaust fan (7) and the circulation mechanism (11 - 15) are operated in a state where the heat source (4) has stopped than when the heat source (4) is operated. A grain dryer characterized by this.

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