JPH10274476A - Grain-drying method and grain-drying device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the radiation efficiency of far-infrared rays and to prevent grain from being damaged and an insufficient drying state from occurring by calculating the ratio of applied energy equivalent to an amount of combustion to the radiation energy of far-infrared rays as a far-infrared ray contribution rate. SOLUTION: A control part 30 for executing the speed control of a suction fan 6 has a microcomputer that can be operation-controlled as a main part. Then, a surface temperature sensor 31 for detecting the surface temperature of a radiation pipe, an amount-of-grain input part 32, a means 33 for detecting an amount of combustion by a burner are connected to an input side via an I/O interface, and a rotary drive part 34 of a suction fan is connected to an output side. The control part 31 calculates a far-infrared ray contribution rate using the surface temperature of the radiation pipe and the amount of combustion by a burner. Then, the amount of hot wind that affects the ambient temperature of the radiation pipe is adjusted so that the contribution rate becomes constant, thus improving the radiation efficiency of far infrared rays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for drying cereals using far infrared rays.
Provided is a grain drying method and a grain drying apparatus capable of performing reliable drying by maintaining radiation efficiency at or above a certain level.

[0002]

2. Description of the Related Art In order to dry cereals such as glutinous rice, cereal drying apparatuses for drying cereals using hot air have been used. Furthermore, in order to dry these grains reliably and without damaging them, a grain drying apparatus that dries grains using far-infrared rays together with the hot air is considered.
It is also widely used. Such a grain drying apparatus using far-infrared rays is disclosed in, for example, JP-A-61-1952.
No. 65, No. 62-141486, No. 62-2
No. 13,680, JP-A-2-302578, and JP-A-6-3052. FIG. 7 shows a grain drying apparatus described in the above-mentioned Japanese Patent Application Laid-Open No. 2-302578. Hereinafter, a conventionally known grain drying apparatus will be briefly described by taking the structure shown in FIG. 7 as an example.

The grain dryer 1 has a bucket elevator 3 erected outside a box-shaped casing 2, a burner 4 as a hot air source, a heat distribution chamber 5, a suction fan 6 as a blower, an inflow air conditioner. A part 7 and the like are provided. In the casing 2, a grain storage unit 8, a drying unit 9, and a grain collection unit 10 are provided in this order from the top. A grain distribution screw 11 that communicates with the upper end of the bucket elevator 3 to laterally convey grains and distributes grains into the grain reservoir 8 is disposed above the grain reservoir 8. A grain collecting / conveying screw 12 is provided at the bottom of the grain collecting section 10 and communicates with the lower end of the bucket elevator 3. The bucket elevator 3 has a hopper (not shown) for embedding grain.
Is provided, and the grain can be freely inserted into the grain storage unit 8 via the grain distribution screw 11. During the drying operation, the grains to be dried discharged by the grain collecting and conveying screw 12 are sent to the grain distribution screw 11 and circulated. Further, when the drying operation is completed, it is possible to switch so that the dried grain is discharged from the bucket elevator 3 to the outside of the machine.

The drying section 9 has one end communicating with the heat distribution chamber 5 and the other end communicating with the inflow air adjusting section 7.
A plurality of tubular hot air passages 13 are provided. The hot air passage 13 is partially provided with a far-infrared radiator. The far-infrared radiator is formed by, for example, applying fine ceramics to a member constituting the hot air passage 13.

In the case of the conventional structure shown in the figure, the hot air passage 13 has a double tube structure of an inner tube 15 and an outer tube 16. As shown, only the inner pipe 15 communicates with the heat distribution chamber 5, and the end of the outer pipe 16 on the heat distribution chamber 5 side is in contact with the inner surface of the casing 2. The two spaces formed by the inner pipe 15 and the outer pipe 16 are opened to communicate with the grain storage section 8 through a number of vents of the outer pipe 16, and the exhaust path plate 17 extends from the side to the lower side. To form a grain logistics pathway,
Rotary valves 19, 19 are provided at the bottom of the grain distribution lower road. The suction fan 6 communicates with an exhaust passage formed below the exhaust passage plate 17. The grains discharged from the rotary valves 19, 19 are brought to the grain collecting and conveying screw 12.

In the grain drying apparatus constructed as described above, the grain to be dried, such as waxy rice, to be dried is put into the grain storage section 8 by the bucket elevator 3 via the grain distribution screw 11, and the bucket elevator 3, the grain In addition to the distribution screw 11, the burner 4, the suction fan 6,
By operating the rotary valve 19, the grain collecting / transporting screw 12, and the like, the dried grain is removed from the grain storage unit 8,
It is circulated and dried in the path of the drying section 9, the grain collecting section 10, and the bucket elevator 3. The circulation speed is determined mainly by the rotation speed of the rotary valve 19.

[0007] The hot air generated by the combustion of the burner 4 is introduced from the heat distribution chamber 5 to the hot air passages 13, 13, which heat the far-infrared radiator to generate electromagnetic waves containing much far-infrared rays. The grains flowing down the grain distribution lower route 18 are dried. The hot air that has reached the inflow air adjusting section 7 after heating the far-infrared radiator is mixed with the outside air here and is discharged from the outer tube 16 through the passage between the inner tube 15 and the outer tube 16. By the attraction of the suction fan 6, the grain is dried by forcibly passing through the grain flowing down the grain distribution lower passage. or,
The moisture generated by the drying and the fine dust generated by the movement of the grains are attracted by the suction fan 6 through the exhaust path plate 17 and discharged outside the machine. It is to be noted that so-called tempering can be freely performed during the drying operation.

When the drying operation is completed, the combustion of the burner 4 is stopped, the circulation path of the bucket elevator 3 is switched, and the dried grain is discharged outside the machine.

In the grain drying apparatus described in the above-mentioned publication, electromagnetic waves containing a large amount of far-infrared rays can be uniformly and directly applied to grains flowing down around the far-infrared radiator, thereby eliminating heat loss of far-infrared rays and improving efficiency. Good grain drying can be performed. At the same time, drying unevenness can be reduced, and the occurrence of body cracks can be eliminated.

[0010]

The wavelength of far-infrared rays to be radiated is an important factor for efficient and reliable drying. To keep the heat applied to the far-infrared radiator constant, It is necessary to keep the temperature around the far-infrared radiator constant. To this end, it is conceivable to devise the area and arrangement of the radiator according to the amount of grain to be dried. However, it is difficult to change the area and arrangement, and this is not practical. Therefore, in the conventional grain drying apparatus, the optimum burning amount of the burner 4 is set, and the drying operation is performed with the set constant burning amount.

As a method for keeping the temperature around the far-infrared radiator constant, the temperature of hot air passing through the far-infrared radiator is detected, and the optimum combustion amount of the burner 4 is set based on the detected temperature. Have been done. However, the hot air used for temperature detection is hot air that is exhausted in a state of being mixed with the outside air at an inflow air adjusting unit (a portion indicated by reference numeral 7 in FIG. 7) after passing through a far-infrared radiator. Cannot detect the temperature directly from the far-infrared radiator. That is, the temperature of the exhaust hot air not only tends to drop due to heat reception to the grains or loss in the hot air passage, but also varies depending on the air volume in the drying device. For this reason, when trying to adjust the temperature around the far-infrared radiator by controlling the combustion amount of the burner 4 using the temperature of the exhaust hot air as a material for determining the drying ability of the far-infrared radiator, the radiation efficiency is excessively increased or On the other hand, it is extremely reduced, and there is a possibility that the grain to be dried may be damaged or a reliable drying operation cannot be performed.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the conventional grain drying apparatus using far-infrared rays, it is an object of the present invention to stabilize the radiation efficiency of far-infrared rays from a far-infrared radiator irrespective of a change in the amount of combustion at a hot air source. It is an object of the present invention to provide a grain drying method using far-infrared rays and a grain drying apparatus using the same, which can prevent the damage of the grain and an insufficient drying state.

[0013]

Means for Solving the Problems To achieve this object, the invention according to claim 1 is directed to a grain drying method for drying grains by far-infrared hot air obtained by a hot-air generating source and a far-infrared radiator. The surface temperature of the far-infrared radiator is directly or indirectly detected, and the amount of combustion at the hot air source is detected. The amount of combustion corresponding to the amount of combustion is determined by the relationship between the amount of combustion and the surface temperature of the far-infrared radiator. It is characterized in that the ratio between the energy and the radiant energy of the far-infrared ray is calculated as the far-infrared ray contribution rate, and this far-infrared ray contribution rate is maintained at a certain level or more.

According to a second aspect of the present invention, in the grain drying method according to the first aspect, the far-infrared ray contribution rate detects a surface temperature of the far-infrared radiator, and the hot-air generating source according to the surface temperature. It is characterized in that it is maintained at a certain level or more by adjusting the flow rate of hot air from the air.

According to a third aspect of the present invention, in a grain drying method for drying a grain using far-infrared hot air obtained by a hot-air generating source and a far-infrared radiator, the temperature of hot air immediately after passing through the far-infrared radiator is detected. At the same time, the amount of combustion at the source of hot air is detected, and the ratio of the input energy corresponding to the amount of combustion to the radiant energy of far-infrared radiation is determined by the relationship between the amount of combustion and the surface temperature of the far-infrared radiator. It is characterized in that it is calculated as a ratio and the far-infrared contribution ratio is maintained at a certain value or more.

The invention described in claim 4 is the first and second aspects of the present invention.
A grain drying apparatus using the grain drying method described above, wherein a surface temperature sensor capable of directly or indirectly detecting a surface temperature of a far-infrared radiator, a combustion amount detection unit at the hot air generation source, and the hot air generation Flow rate control means capable of setting the flow rate of hot air from a source, the surface temperature sensor and the combustion amount detection means are connected to the input side, the control unit is provided with the flow rate control means is connected to the output side, The control unit uses the amount of combustion at the hot-air source and the radiant energy from the far-infrared radiator to calculate the far-infrared contribution rate = radiant temperature × surface area × coefficient / burning amount ×
The heat generation amount × 100 (%) is obtained, and when the contribution ratio is not at the predetermined far-infrared ray contribution ratio, the amount of hot air is controlled by the flow rate control means.

According to a fifth aspect of the present invention, in the grain drying apparatus according to the fourth aspect, the surface temperature sensor faces the far-infrared radiator in a state of being in contact with or not in contact with the surface of the far-infrared radiator. It is characterized by being arranged.

[0018]

According to the first, second, fourth and fifth aspects of the present invention, the surface temperature of the far-infrared radiator itself is directly or indirectly detected, and the detected surface temperature of the far-infrared radiator and the hot-air source are detected. Calculate the far-infrared contribution ratio with the amount of combustion at
The ambient temperature of the far-infrared radiator can be controlled by adjusting the air flow so that the far-infrared contribution ratio is equal to or higher than a certain value. With this, unlike the case where the exhaust hot air is detected as the ambient temperature of the far-infrared radiator, the actual ambient temperature of the far-infrared radiator can be accurately grasped. The accuracy of stabilizing the far-infrared radiation efficiency can be enhanced based on the temperature information directly obtained from the far-infrared radiator.

According to the third aspect of the present invention, the far-infrared ray contribution rate is calculated using the hot air temperature immediately after passing through the far-infrared ray radiator. For this reason, the far-infrared ray contribution rate can be calculated without targeting the temperature of the far-infrared radiator, and an exhaust temperature sensor for hot air immediately after passing through the far-infrared radiator is added to the existing structure. A structure for improving the far-infrared radiation efficiency can be obtained with a simple structure.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; The grain drying apparatus used in the grain drying method according to the present invention directly or indirectly detects the surface temperature of the far-infrared radiator, and determines the amount of combustion of the hot air source that affects the surface temperature and the distance from the far-infrared radiator. It is characterized in that the far-infrared contribution ratio obtained by the ratio of the infrared radiation energy to the radiant energy is maintained at a certain level or more, and other configurations are the same as those of the above-described conventional device.

FIG. 1 is a perspective view for explaining a main part of an embodiment of the invention according to claims 1, 2, 4 and 5. In FIG. 1, a grain drying apparatus is the same as the above-described conventional apparatus. A burner 4 capable of generating hot air, a radiation tube 21 capable of emitting far-infrared rays by the heat of the hot air generated by the burner 4, and a suction fan 6 for diffusing the air around the radiation tube 21 (see FIG. 2). And The burner 4 corresponds to a hot air generation source, and can change a combustion amount according to a fuel supply amount from a fuel supply control device (not shown). The radiation tube 21 corresponds to a far-infrared radiator. In this embodiment, the radiation tube 21 is configured by applying a material capable of radiating far-infrared light such as fine ceramics to a metal material such as stainless steel. Further, the suction fan 6 corresponds to a flow rate control means capable of adjusting the amount of hot air blown,
The air volume can be adjusted by the number of rotations according to the applied current value determined by the control unit described later.

In FIG. 1, the burner 4 is provided on one end face of the first heat distribution chamber 5, and the hot air generated by the burner 4 is sent to the first heat distribution chamber 5. One end of a communication pipe 22 is connected to the other end surface of the first heat distribution chamber 5, and a second heat distribution chamber 23 is connected to the other end of the communication pipe 22. The second heat distribution chamber 23 is provided with a pair of radiation tubes 21. Radiation tube 21
Is formed in a tubular shape having both ends opened, and hot air generated by the burner 4 is supplied to the first heat distribution chamber 5 and the communication pipe 2.
2. It is sent out from the other end opening of the radiation tube 21 through the second heat distribution chamber 23. These constituent members 5, 21, 22, and 23 are arranged in a state of being housed in the casing 2 as shown in FIGS.

FIG. 3 shows the configuration of the control unit for controlling the rotation speed of the suction fan 6. In FIG. 3, a control unit 30 includes a microcomputer which can be arithmetically controlled as a main unit, and a surface temperature sensor 31 for detecting a surface temperature of the radiation tube 21 on an input side via an I / O interface (not shown), a grain quantity input unit. 32, a combustion amount detection means 33 in the burner 4 is connected, and a rotation drive unit 34 of the suction fan 6 is connected to the output side. In the case of the present embodiment, the surface temperature sensor 31 is, as shown in FIG.
1 where the temperature is most stable in the full length direction of 1
The contact tube or the non-contact thermistor is used as its structure, and the temperature of the radiation tube 21 is directly or indirectly detected. Although not shown, the grain amount input unit 32 includes a grain storage unit 8.
(See FIG. 7) or a numeric keypad provided on an operation panel (not shown). The combustion amount detecting means 33 is a means for detecting the amount of fuel supplied to the burner 4, and is based on a measurement result of a flow meter, a duty ratio for fuel supply set by a fuel supply control device, a driving time of a fuel pump, or the like. The fuel supply amount per unit time can be detected. Note that the detection of the fuel supply amount by the combustion amount detection means 33 can be obtained by arithmetic processing by the control unit 30.

The control unit 30 calculates the far-infrared ray contribution ratio using the surface temperature of the radiation tube 21 and the amount of combustion in the burner 4, and calculates the ambient temperature of the radiation tube 21 so that the contribution ratio becomes a certain value or more. The amount of hot air that affects the air flow is adjusted. The contribution rate of the far-infrared ray is calculated using the radiant energy of the far-infrared ray obtained from the surface temperature of the radiation tube 21 and the input energy corresponding to the amount of combustion in the burner 4. Coefficient / burn amount x heat value) x 100 (%). The far-infrared contribution rate is 25 as a constant value.
On the basis of (%), the control unit 20 controls the rotation speed of the suction fan 6 so as to maintain the value or more. As the far-infrared ray contribution rate increases, the radiation efficiency of far-infrared rays increases, and electromagnetic waves including far-infrared rays penetrate sufficiently into the interior of the grain, and the amount of water removed (Kg) in the grain per 1 kg of combustion amount The drying efficiency represented by the ratio will be improved.

In the present embodiment, the grain is dried based on the operation of the control unit 30 described below using the apparatus having the above-described configuration. FIG. 4 is a flowchart for explaining the operation of the control unit 30. In FIG. 4, when the operation of the drying apparatus is started, the surface temperature of the radiation tube 21 is increased by the surface temperature sensor 31 and the combustion amount detecting means 32. And the amount of combustion in the burner 4 is detected (S1, S2). Each information obtained in steps S1 and S2 is taken into the control unit 30, and the control unit 30 calculates a far-infrared ray contribution ratio (S3). In this case, the above-mentioned expression is used as the operation expression. It is determined whether or not the calculated far-infrared ray contribution ratio is equal to or more than a certain value, and in the case of this embodiment, is not less than 25% (S
4) If it is not less than a certain value, the current air volume is maintained (S5). On the other hand, if the far-infrared contribution ratio is not equal to or more than the predetermined value in step S4, the air flow is reduced (S
6). The air volume is reduced stepwise, and the feedback control based on the far-infrared contribution ratio obtained with the reduced air volume is executed. If it is determined in step S4 that the far-infrared contribution ratio is not equal to or more than the predetermined value, it is possible to control the amount of combustion of the burner 4 to adjust the amount of heat generated by the hot air generated by the burner 4. Since the temperature around the radiation tube 21 does not always change in proportion to the change in the amount of combustion of the burner 4, the temperature of the burner 4 may unnecessarily rise. Therefore, it is preferable for safety to control the temperature around the radiation tube 21 by the heat storage amount of the air flowing around the radiation tube 21. For this reason, in the present embodiment, when the far-infrared ray contribution rate is not equal to or more than a certain value, the amount of heat stored in the air flowing around the radiation tube 21 is changed to improve the radiation efficiency of far-infrared radiation from the radiation tube 21. It is supposed to. When the combustion amount is changed, for example, a change in the amount of grain to be dried or a drying time is a parameter. The above processing is continued until the drying time expires or the operation switch is switched to the stop state (S7).

According to the present embodiment, the surface temperature of the radiation tube 21 is detected directly or indirectly, in other words, far-infrared radiation is performed on the temperature information from the radiation tube 21 which directly affects the drying efficiency. Since a process for improving the efficiency can be performed, it is possible to improve the accuracy of the temperature information from the radiation tube 21 and improve the drying efficiency.

Next, the third aspect of the present invention will be described. The invention according to claim 3 detects the temperature of hot air immediately after passing through the far-infrared radiator, and detects the temperature based on the difference between the exhaust energy obtained from the temperature and the input energy obtained from the amount of combustion at the hot air source. It is characterized in that the radiant energy of the infrared radiator is calculated to obtain the far-infrared contribution ratio. That is, FIG. 5 is a block diagram for explaining a control mechanism used in the present embodiment. The difference from the embodiment described above in FIG. 5 is that the surface temperature sensor 31 is not used. In the embodiment shown in FIG. 5, instead of the surface temperature sensor 31, an exhaust temperature sensor 31 'capable of detecting the temperature of the exhaust hot air immediately after passing through the radiation tube 21 is connected to the input side of the control unit 30'. In this case, immediately after passing through the far-infrared radiator corresponds to before mixing with the outside air. The control unit 30 ′ uses the amount of combustion in the burner 4 and the temperature of the hot air exhaust,

(Equation 1) Ask for. When the far-infrared contribution rate is obtained, the control section 30 'controls the rotation speed of the suction fan 6 so that the contribution rate is equal to or higher than a certain value. This air volume control is the same as in the above-described embodiment.

Since the present embodiment has the above configuration,
The operation of the control unit 30 will be described with reference to the flowchart illustrated in FIG. In FIG. 6, when the drying operation is started, when the temperature of the exhaust hot air and the combustion amount at the bar 4 are detected by the exhaust gas temperature sensor 31 'and the combustion amount detecting means 33 (S1', S2 '), the distance is increased. An infrared contribution ratio is calculated (S3). It is determined whether or not the calculated far-infrared ray contribution ratio is equal to or more than a certain value (S4), and the processing corresponding to the Minister is executed as the same processing as steps S5 to S7 shown in FIG.

According to this embodiment, the exhaust gas temperature sensor 31 '
Since the temperature of hot air immediately after passing through the radiation tube 21 is targeted for detection, it is possible to install a sensor after assembling the radiation tube 21. It can also be used to calculate the infrared contribution. This makes it possible to improve the drying efficiency only by adding a simple structure.

The surface temperature sensor 31 and the exhaust gas temperature sensor 31 'shown in FIGS. 3 and 5 are used not only for detecting the surface temperature and the exhaust gas temperature but also for detecting the abnormal temperature of the radiation tube. Since it can be used, it becomes possible to use it as a member for taking safety measures especially by detecting overheating of the radiation tube beforehand.

[0031]

As described above, according to the first, second, fourth, and fifth aspects of the present invention, the surface temperature is directly or indirectly detected for the far-infrared radiator itself, and the detected far-infrared radiator is detected. Calculate the far-infrared contribution rate based on the surface temperature of the infrared radiator and the amount of combustion at the hot air source, and control the ambient temperature of the far-infrared radiator by adjusting the air flow so that the far-infrared contribution rate is equal to or higher than a certain value Can be. This makes it possible to accurately grasp the actual ambient temperature of the far-infrared radiator, unlike the case where the exhaust hot air is regarded as the ambient temperature of the far-infrared radiator. Instead, based on the temperature information directly obtained from the far-infrared radiator, it is possible to enhance the accuracy of stabilizing the far-infrared radiation efficiency and perform good drying.

According to the third aspect of the present invention, the far-infrared ray contribution rate is calculated using the hot-air temperature just after passing through the far-infrared radiator. A structure for improving the far-infrared radiation efficiency can be obtained by a simple structure simply by adding the exhaust temperature sensor described above.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a main part of an embodiment of the invention described in claims 1, 2, 4, and 5;

FIG. 2 is an external view of a main part shown in FIG.

FIG. 3 is a block diagram for explaining a configuration of a control unit used for a main part shown in FIG. 1;

FIG. 4 is a flowchart for explaining the operation of the control unit shown in FIG. 3;

FIG. 5 is a block diagram for explaining a configuration of a control unit corresponding to a main part of the embodiment of the invention described in claim 3;

FIG. 6 is a flowchart for explaining the operation of the control unit shown in FIG. 5;

FIG. 7 is a schematic perspective view for explaining an example of a grain drying apparatus.

[Explanation of symbols]

 Reference Signs List 2 Casing 4 Burner corresponding to hot air generation source 6 Suction fan corresponding to flow rate control means 21 Radiation tube 30, 30 'Control unit 31 Surface temperature sensor 31' Exhaust temperature sensor 33 Combustion amount detection means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kotaro Kubota 1-40-2 Nisshincho, Omiya City, Saitama Prefecture Within the Research Institute for Biological Sciences (72) Inventor Yasuyuki Hidaka 1-chome Nisshincho, Omiya City, Saitama Prefecture 40-2 In the Research Institute for Specified Biotechnology (72) Inventor Tomohiko Ichikawa 1-40-2 Nisshincho, Omiya-shi, Saitama

Claims (5)

[Claims] 1. A grain drying method for drying a grain by far-infrared hot air obtained from a hot-air generating source and a far-infrared radiator, wherein a surface temperature of the far-infrared radiator is directly or indirectly detected and the hot air is detected. Detects the amount of combustion at the source,
The ratio between the input energy corresponding to the amount of combustion and the radiant energy of the far infrared ray is calculated as the far infrared ray contribution rate based on the relationship between the surface temperature of the far infrared ray radiator and the above combustion quantity, and this far infrared ray contribution rate is kept to a certain value or more A grain drying method characterized by maintaining. 2. The grain drying method according to claim 1, wherein the far-infrared ray contribution ratio detects a surface temperature of the far-infrared ray radiator, and determines a flow rate of the hot air from the hot air source according to the surface temperature. A grain drying method using far-infrared rays, which is maintained at a certain level or more by adjusting. 3. A grain drying method for drying a grain by far-infrared hot air obtained by a hot-air generating source and a far-infrared radiator, wherein the hot-air generating source is detected immediately after passing through the far-infrared radiator. In the detection of the amount of combustion at, the ratio of the input energy corresponding to the amount of combustion and the radiant energy of far-infrared rays as the far-infrared contribution rate by calculating the relationship between the amount of combustion and the surface temperature of the far-infrared radiator, A grain drying method comprising maintaining a far-infrared ray contribution ratio at a certain level or more. 4. A grain drying apparatus using the grain drying method according to claim 1 or 2, wherein a surface temperature sensor capable of directly or indirectly detecting a surface temperature of a far-infrared radiator; Combustion amount detection means, a flow rate control means capable of setting a flow rate of hot air from the hot air generation source, the surface temperature sensor and the combustion amount detection means are connected to an input side, and the flow rate control means is connected to an output side. A control unit connected thereto, wherein the control unit uses the amount of combustion at the hot-air generating source and the radiant energy from the far-infrared radiator to calculate a far-infrared contribution ratio = radiator temperature × surface area × coefficient / Burning amount ×
A drying apparatus characterized in that a calorific value x 100 (%) is determined, and when the contribution rate is not at a predetermined far-infrared ray contribution rate, the flow rate of the hot air is controlled by the flow control means. 5. The grain drying device according to claim 4, wherein the surface temperature sensor is arranged to face the far-infrared radiator while being in contact with or not in contact with the surface of the far-infrared radiator. A grain dryer.