Seed disinfection device

Abstract

To accurately determine the appropriateness of heat disinfection of seeds.SOLUTION: A disinfection device 100 comprises: a heating unit 2 that heats seeds with steam for disinfection; a preliminary cooling unit 3 that cools the seeds after heating by the heating unit 2; a temperature sensor 5 that detects a cooling temperature being the temperature of the seeds after cooling by the preliminary cooling unit 3; and a control device 8 that sets, as a cooling target range, a range of the cooling temperatures corresponding to a predetermined heating target range of heating temperatures on the basis of a correlation between the cooling temperature and the heating temperature being the temperature of the seeds after heating by the heating unit 2 according to the cooling capacity of the preliminary cooling unit 3, and determines whether the cooling temperature detected by the temperature sensor 5 is included in the cooling target range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for disinfecting seeds. [Background technology]

[0002] Disinfection devices that disinfect seeds with steam are known. For example, the disinfection device disclosed in Patent Document 1 disinfects seeds by heating them with steam, and then cools the seeds to dry them before discharging them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-55259 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because insufficient heating of seeds results in insufficient disinfection, and overheating of seeds reduces germination rates, accurately determining the appropriateness of heat disinfection is extremely important. Therefore, it is conceivable to determine the appropriateness of heat disinfection based on the seed heating temperature, i.e., the temperature immediately after heating. However, it is difficult to measure the temperature immediately after heating. For example, when directly measuring seed temperature using a thermocouple, the seeds must be temporarily stored until their temperature reaches equilibrium. This method maintains the seeds at a high temperature for several tens of seconds to several minutes, resulting in a reduced seed germination rate. Furthermore, the non-contact method of measuring seed surface temperature using a radiation temperature sensor is undesirable because a large amount of water vapor is released from the seed surface immediately after heating, which is affected by water droplets.

[0005] The present invention has been made in view of the above circumstances, and its object is to provide a sterilization device that can accurately determine whether or not heat sterilization of seeds is appropriate. [Means for solving the problem]

[0006] The seed sterilization device of the present invention includes a heating unit, a cooling unit, a temperature sensor, and a control unit. The heating unit sterilizes seeds by heating them with steam. The cooling unit cools the seeds after heating by the heating unit. The temperature sensor detects a cooling temperature, which is the temperature of the seeds after cooling by the cooling unit. The control unit sets a cooling temperature range corresponding to a predetermined heating target range of the heating temperature as a cooling target range based on a correlation between the cooling temperature and a heating temperature, which is the temperature of the seeds after heating by the heating unit, depending on the cooling capacity of the cooling unit, and determines whether the cooling temperature detected by the temperature sensor is within the cooling target range.

[0007] In the above configuration, the seeds are heat-sterilized by being exposed to steam in the heating section. Then, the seeds are cooled in the cooling section to be cooled and dried. That is, the temperature of the seeds is reduced from the heating temperature to the cooling temperature. The cooling temperature of the seeds is detected by a temperature sensor. The control device sets a target cooling range for the cooling temperature based on the correlation between the cooling temperature and the heating temperature. The correlation is obtained, for example, by experiment. The heating temperature corresponds to the temperature of the seeds before cooling by the cooling section, and the temperature of the seeds before and after cooling by the cooling section have a certain relationship depending on the cooling capacity of the cooling section.

[0008] The control device then determines whether the cooling temperature detected by the temperature sensor is within a target cooling range. The target cooling range is a range of cooling temperatures corresponding to a predetermined target heating range of heating temperatures, and the target heating range is set to a range of heating temperatures for which thermal sterilization by the heating unit is appropriate. In other words, seeds whose heating temperature is within the target heating range are cooled by a cooling unit with a certain cooling capacity to a temperature within the target cooling range. Therefore, if the cooling temperature is within the target cooling range, the heating temperature can also be considered to be within the target heating range, and it can be determined that thermal sterilization by the heating unit is appropriate. On the other hand, if the cooling temperature is not within the target cooling range, the heating temperature can also be considered to be not within the target heating range, i.e., the heating temperature is considered to be too high or too low, and it can be determined that thermal sterilization by the heating unit is inappropriate. In this way, the appropriateness of thermal sterilization of seeds is accurately determined. In other words, the sterilization device of the present invention substitutes the cooling temperature for the heating temperature, which is difficult to measure, and determines the appropriateness of thermal sterilization of seeds based on the cooling temperature.

[0009] The sterilization apparatus includes a front-stage cooling section as the cooling section, and further includes a rear-stage cooling section that further cools the seeds after cooling by the front-stage cooling section. The cooling temperature is the temperature of the seeds after cooling by the front-stage cooling section and before cooling by the rear-stage cooling section.

[0010] In the above configuration, seeds that have been heat-sterilized by the heating unit are cooled in two stages by the front-stage cooling unit and the rear-stage cooling unit. In the front-stage cooling unit, the heat-sterilized seeds are cooled (more specifically, rapidly cooled) to a temperature within a target cooling range. The temperature within the target cooling range is set, for example, to a temperature below which the seed germination rate will not decrease. If seeds are maintained at a predetermined temperature or higher, the germination rate will decrease. In the rear-stage cooling unit, the seeds that have been cooled to a temperature within the target cooling range are gradually cooled (i.e., slowly cooled) to a predetermined temperature (e.g., ambient temperature + several degrees Celsius) at which they are sufficiently dried. Since gradual cooling to the predetermined temperature is sufficient, the required cooling capacity of the rear-stage cooling unit is low. Therefore, compared to, for example, rapidly cooling heat-sterilized seeds all at once to a predetermined temperature at which they are sufficiently dried, the overall required cooling capacity can be kept low while still suppressing a decrease in germination rate.

[0011] Furthermore, since the temperature of the seeds after cooling by the front-stage cooling section but before cooling by the rear-stage cooling section is used as the cooling temperature, the accuracy of determining whether heat disinfection is appropriate is improved. That is, the temperature fluctuation range of the seeds after cooling by the front-stage cooling section is larger than the temperature fluctuation range of the seeds after cooling by the rear-stage cooling section. This is because the temperature of the seeds after cooling by the front-stage cooling section is more unstable due to a larger difference from the ambient temperature than the temperature of the seeds after cooling by the rear-stage cooling section. As a result, it is easier to capture the temperature fluctuations of the seeds after cooling by the front-stage cooling section, making it easier to set the target cooling range. Therefore, by using the temperature of the seeds after cooling by the front-stage cooling section as the cooling temperature, rather than the temperature of the seeds after cooling by the rear-stage cooling section, the appropriateness of heat disinfection can be determined with high accuracy.

[0012] When the control device determines that the cooling temperature detected by the temperature sensor is not within the target cooling range, it controls the amount of heat applied to the seeds by the heating unit so that the cooling temperature detected by the temperature sensor is within the target cooling range.

[0013] In the above configuration, if the cooling temperature is not within the target cooling range, the amount of heat applied to the seeds is controlled so that the cooling temperature is within the target cooling range. Specifically, if the cooling temperature is higher than the target cooling range, the heating temperature is deemed to be too high, and the amount of heat applied to the seeds is reduced. Also, if the cooling temperature is lower than the target cooling range, the heating temperature is deemed to be too low, and the amount of heat applied to the seeds is increased. This brings the cooling temperature into the target cooling range, and thermal sterilization by the heating unit is appropriate.

[0014] When the control device determines that the cooling temperature detected by the temperature sensor is not within the target cooling range, it stops supplying seeds to the heating unit.

[0015] In the above configuration, if the cooling temperature is not within the target cooling range, the supply of seeds to the heating section is stopped, thereby reducing the amount of seeds that are inappropriately heat-sterilized in the heating section.

[0016] The sterilization device further includes a switch for switching between a shipping route for shipping the seeds and a standby route for temporarily waiting the seeds after cooling by the cooling unit. When the control device determines that the cooling temperature detected by the temperature sensor is not within the target cooling range, the switch switches to the standby route.

[0017] In the above configuration, if the cooling temperature is not within the target cooling range, the route for the seeds after cooling by the cooling unit is switched to the standby route, so that seeds that have been inappropriately heat-sterilized by the heating unit are temporarily put on standby without being shipped.

[0018] The heating section heats the seeds while transporting them by rolling them.

[0019] In the above configuration, the heating unit transports the seeds by rolling them. That is, the heating unit heats the seeds with steam while rolling them. This allows the seeds to be uniformly heat-sterilized. Therefore, unevenness in the heating temperature and, in turn, unevenness in the cooling temperature are suppressed. This increases the uniformity of the cooling temperature, improving the accuracy of determining whether heat sterilization is appropriate. [Effects of the Invention]

[0020] As described above, the seed disinfection device of the present invention can accurately determine whether or not seeds are suitable for heat disinfection. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram showing a disinfection device. [Figure 2] FIG. 2 is a plan view showing the troughs of the front-stage cooling section and the rear-stage cooling section. [Figure 3] FIG. 2 is a block diagram showing a control device and its peripheral devices. [Figure 4] 4 is a flowchart showing a process performed by a control device. [Figure 5] 10 is a flowchart showing a process performed by a control device according to a modified example. [Figure 6] FIG. 10 is a plan view showing troughs in a front-stage cooling section and a rear-stage cooling section according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Exemplary embodiments will now be described in detail with reference to the drawings, in which: Figure 1 is a schematic diagram showing a disinfection device 100;

[0023] The sterilization apparatus 100 is a sterilization apparatus for seeds of paddy rice, wheat, etc. Specifically, the sterilization apparatus 100 heats and sterilizes the seeds while transporting them, and then cools the seeds while transporting them and discharges them to a shipping route. The sterilization apparatus 100 includes a supply unit 1, a heating unit 2, a front-stage cooling unit 3, a rear-stage cooling unit 4, a temperature sensor 5, a discharge unit 6, and a control device 8.

[0024] The supply unit 1 supplies seeds to the heating unit 2. Specifically, the supply unit 1 has an elevator 11 and a tank 12. The elevator 11 transports the seeds to be disinfected to the tank 12. The tank 12 temporarily stores the seeds transported from the elevator 11 and intermittently supplies a predetermined amount of seeds to the heating unit 2.

[0025] In the following figures, the flow of seeds is indicated by solid arrows, the flow of steam is indicated by dashed arrows, the flow of air is indicated by dashed double-dashed lines, and the flow of cool air is indicated by dashed arrows.

[0026] The heating unit 2 heats and sterilizes the seeds supplied from the supply unit 1 with steam. Specifically, the heating unit 2 heats the seeds while transporting them, more specifically, by rolling the seeds while transporting them. The heating unit 2 has a steam unit 21, a first heater 22a, a second heater 22b, a trough 23, a vibrator 24, and fans 25 and 26.

[0027] Steam unit 21 supplies steam (e.g., saturated steam at 100°C) supplied from boiler 110 to second heater 22b. At that time, steam unit 21 appropriately adjusts the pressure and flow rate of the steam. First heater 22a heats air supplied by blower 26 and supplies the air to second heater 22b. Second heater 22b mixes the steam supplied from steam unit 21 with the air supplied from first heater 22a at a predetermined ratio, superheats the mixture, and generates steam at a predetermined temperature (e.g., a temperature higher than 100°C). The steam is supplied to trough 23.

[0028] The trough 23 transports the seeds supplied from the tank 12. Specifically, the trough 23 is formed in the shape of a long plate extending approximately horizontally, and transports the seeds to one side in the longitudinal direction of the trough 23. More specifically, the trough 23 is slightly inclined downward toward one side in the longitudinal direction. The vibrator 24 vibrates the trough 23 back and forth in the longitudinal direction. By vibrating back and forth in the longitudinal direction, the trough 23 rolls the seeds and transports them to one side in the longitudinal direction. The seeds transported in the trough 23 are heated by being exposed to steam supplied from the second heater 22b. In this way, the seeds are heated and sterilized by the steam while being transported. The blower 25 sucks in and discharges the steam after heating the seeds. The heating section 2 supplies the heated seeds to the pre-cooling section 3.

[0029] The front-stage cooling section 3 and the rear-stage cooling section 4 cool the seeds after heating by the heating section 2. Specifically, the seeds after heating by the heating section 2 are cooled in two stages by the front-stage cooling section 3 and the rear-stage cooling section 4. The front-stage cooling section 3 cools the seeds immediately after heating by the heating section 2, more specifically, rapidly cools the seeds immediately after heating to a temperature that does not reduce the germination rate. The rear-stage cooling section 4 further cools the seeds after cooling by the front-stage cooling section 3, more specifically, slowly cools the cooled seeds to a temperature that sufficiently dries them. In other words, the front-stage cooling section 3 has a certain cooling capacity that can rapidly cool the seeds from a temperature within the heating target range to a temperature that does not reduce the germination rate, and the rear-stage cooling section 4 has a certain cooling capacity that can slowly cool the seeds from a temperature that does not reduce the germination rate to a temperature that sufficiently dries them. The front-stage cooling section 3 is an example of a cooling section. When the front-stage cooling section 3 and the rear-stage cooling section 4 are referred to collectively, they are referred to as cooling sections 3 and 4.

[0030] The front-stage cooling section 3 has a trough 31, a vibrator 32, and two air blowers 33 and 34. The trough 31 transports the seeds supplied from the heating section 2. More specifically, the trough 31, like the trough 23 of the heating section 2, is formed in the shape of a long, substantially horizontal plate, and is vibrated back and forth in the longitudinal direction by the vibrator 32, thereby rolling the seeds and transporting them to one side in the longitudinal direction. The two air blowers 33 and 34 supply cold air, which is air that is lower in temperature than the seeds supplied from the heating section 2, to the trough 31. The seeds transported in the trough 31 are cooled by being exposed to the cold air. In other words, the front-stage cooling section 3 cools the seeds while transporting them. The front-stage cooling section 3 supplies the cooled seeds to the rear-stage cooling section 4.

[0031] The rear-stage cooling section 4 has a trough 41, a vibrator 42, and a blower 43. The trough 41 transports the seeds supplied from the front-stage cooling section 3. More specifically, the trough 41, like the trough 23 of the heating section 2, is formed in the shape of a long, substantially horizontal plate, and is vibrated back and forth in the longitudinal direction by the vibrator 42, thereby rolling the seeds and transporting them to one side in the longitudinal direction. The blower 43 supplies cold air, which is air at a temperature lower than that of the seeds supplied from the front-stage cooling section 3, to the trough 41. The seeds transported in the trough 41 are further cooled by being exposed to the cold air. In other words, the rear-stage cooling section 4 cools the seeds while transporting them. The rear-stage cooling section 4 supplies the cooled seeds to the discharge section 6.

[0032] FIG. 2 is a plan view showing the troughs 31, 41 of the front-stage cooling section 3 and the rear-stage cooling section 4. The troughs 31, 41 are divided into a ventilation section through which cool air passes and a non-ventilation section through which cool air does not pass. Specifically, the trough 31 has a first ventilation section 31a, a second ventilation section 31b, and a non-ventilation section 31c, which are divided in order in the longitudinal direction. The trough 41 has a non-ventilation section 41a and a ventilation section 41b, which are divided in order in the longitudinal direction. In other words, in the trough 31, the seeds are transported through the first ventilation section 31a, the second ventilation section 31b, and the non-ventilation section 31c in that order, and in the trough 41, the seeds are transported through the non-ventilation section 41a and the ventilation section 41b in that order. More specifically, in each of the first ventilation section 31a, the second ventilation section 31b, and the ventilation section 41b, the seeds are cooled by the cool air passing in the vertical direction (i.e., in a direction perpendicular to the troughs 31, 41). Note that the cool air passes in opposite directions in the first ventilation section 31a and the second ventilation section 31b.

[0033] The temperature sensor 5 detects a cooling temperature T, which is the temperature of the seeds after cooling by the front-stage cooling section 3. That is, the cooling temperature T in this example is the temperature of the seeds after cooling by the front-stage cooling section 3 but before cooling by the rear-stage cooling section 4. Specifically, the temperature sensor 5 is provided above the trough 41 of the rear-stage cooling section 4, more specifically, above the non-ventilation section 41a of the trough 41. More specifically, the temperature sensor 5 detects the temperature of the seeds as they are supplied from the trough 31 of the front-stage cooling section 3 to the trough 41 of the rear-stage cooling section 4. The temperature sensor 5 is, for example, a non-contact radiation temperature sensor.

[0034] The discharge unit 6 discharges the seeds supplied from the rear-cooling unit 4 to the shipping path 120 or the waiting path 130. The shipping path 120 is a path for shipping the seeds cooled by the front-cooling unit 3, specifically the seeds cooled by the rear-cooling unit 4, and the waiting path 130 is a path for temporarily waiting the seeds cooled by the rear-cooling unit 4. The discharge unit 6 has an elevator 61 and a switch 62. The elevator 61 transports the seeds supplied from the rear-cooling unit 4 to the switch 62. The switch 62 switches between the shipping path 120 and the waiting path 130. In other words, the switch 62 switches between the shipping path 120 and the waiting path 130 as the discharge destination for the seeds transported by the elevator 61. The sterilization apparatus 100 is also provided with a blower 7 that discharges the steam circulating through the heating unit 2 and the cold air circulating through the cooling units 3 and 4, for example, to the outside of a room.

[0035] 3 is a block diagram showing the control device 8 and its peripheral devices. The control device 8 controls various operations in the sterilization apparatus 100 and determines whether the heating unit 2 is suitable for sterilizing seeds. The control device 8 can communicate with the temperature sensor 5, the tank 12, the first heater 22a, the second heater 22b, the vibrator 24, and the switch 62. Specifically, the control device 8 has an input unit 81, a memory unit 82, a display unit 83, and a processing unit 84.

[0036] The input unit 81 receives an input operation from a user. The input unit 81 outputs an input signal according to the input operation. The input unit 81 is, for example, a keyboard, a mouse, or a touch panel that is overlaid on the display unit 83.

[0037] The memory unit 82 is a computer-readable storage medium that stores various programs and various data. The memory unit 82 is formed of a magnetic disk such as a hard disk, an optical disk such as a CD-ROM or DVD, or a semiconductor memory. Specifically, the memory unit 82 stores correlation data 821 and the like. The correlation data 821 is a correlation between the cooling temperature T according to the cooling capacity of the pre-cooling unit 3 and the heating temperature, which is the temperature of the seeds after heating by the heating unit 2. In other words, multiple pieces of correlation data 821 according to the cooling capacity of the pre-cooling unit 3 are stored. The correlation data 821 is read out by the processing unit 84.

[0038] The display unit 83 displays various information. Specifically, if the heat disinfection of seeds by the heating unit 2 is inappropriate, the display unit 83 displays a warning to that effect. The display unit 83 is, for example, a liquid crystal display or an organic EL display.

[0039] The processing unit 84 has various processors such as a CPU, and various semiconductor memories such as a RAM and / or a ROM. The processing unit 84 determines whether or not thermal disinfection by the heating unit 2 is appropriate based on the correlation data 821 in the storage unit 82, and controls the amount of heat applied to the seeds by the heating unit 2 and the switch 62 according to the determination result. Specifically, the processing unit 84 has a setting unit 841, an acquisition unit 842, a determination unit 843, and a control unit 844 as functional blocks.

[0040] The setting unit 841 sets a predetermined target heating range input from the input unit 81. The target heating range is a target range of heating temperature, which is the temperature of the seeds after heating by the heating unit 2. Furthermore, the setting unit 841 sets a range of cooling temperature T corresponding to the target heating range as a target cooling range (upper limit Ta, lower limit Tb) based on the correlation data 821 in the memory unit 82. In this example, the target cooling range is set to a temperature below which the germination rate of the seeds does not decrease.

[0041] The acquisition unit 842 acquires the cooling temperature T detected by the temperature sensor 5. More specifically, the acquisition unit 842 acquires a detection signal corresponding to the cooling temperature T from the temperature sensor 5.

[0042] The determination unit 843 determines whether or not the cooling temperature T acquired by the acquisition unit 842 is within the target cooling range. That is, the determination unit 843 determines whether or not the heating temperature is within the target heating range, that is, whether or not the heating unit 2 is suitable for heat disinfection of seeds.

[0043] When the control unit 844 determines that the cooling temperature T acquired by the acquisition unit 842 is not within the target cooling range, the control unit 844 controls the amount of heat applied to the seeds by the heating unit 2 so that the cooling temperature T is within the target cooling range. Specifically, the control unit 844 controls the amount of heat by controlling the second heater 22b or the vibrator 24. Furthermore, when the control unit 844 determines that the cooling temperature T is still not within the target cooling range after controlling the amount of heat, the control unit 844 controls the tank 12 and the switch 62.

[0044] Next, the operation of the sterilization apparatus 100 configured as described above will be described. A predetermined amount of seeds is supplied from the tank 12 to the trough 23 of the heating unit 2. The seeds supplied to the trough 23 are heated and sterilized by steam while being transported. In other words, the seeds are heated to a heating temperature within the target heating range. Here, the seeds are transported in a dispersed state because they are rolled. The heat-sterilized seeds are supplied to the trough 31 of the pre-cooling unit 3. The seeds supplied to the trough 31 are cooled by cold air while being transported. More specifically, in the pre-cooling unit 3, the seeds are rapidly cooled to a temperature that does not reduce the germination rate, i.e., to a temperature within the target cooling range. This allows the seeds to be cooled without reducing the germination rate. The seeds cooled in the pre-cooling unit 3 are supplied to the trough 41 of the post-cooling unit 4. At this time, the temperature of the seeds, i.e., the cooling temperature T, is measured by the temperature sensor 5. The seeds in the trough 41, whose cooling temperature T has been measured, are further cooled (more specifically, slowly cooled) by cold air while being transported. This allows the seeds to be cooled to a predetermined temperature (for example, outside air temperature + 5°C) and sufficiently dried. The dried seeds are then discharged to the shipping route 120 by the discharge unit 6.

[0045] Next, the processing of the control device 8 during operation of the above-mentioned sterilization apparatus 100 will be described in detail with reference to Fig. 4. Fig. 4 is a flowchart showing the processing by the control device 8. At the start of operation, the switch 62 switches to the shipping route 120 as the destination for seeds.

[0046] In step Sa1, the determination unit 843 determines whether the cooling temperature T acquired by the acquisition unit 842 is higher than the upper limit value Ta of the target cooling range. More specifically, it determines whether the cooling temperature T has been higher than the upper limit value Ta for a predetermined time ta. In this example, the predetermined time ta is 10 seconds. If the determination in step Sa1 is "NO," the process proceeds to step Sa2. In step Sa2, the determination unit 843 determines whether the cooling temperature T is lower than the lower limit value Tb of the target cooling range. More specifically, it determines whether the cooling temperature T has been lower than the lower limit value Tb for a predetermined time ta. If the determination in step Sa2 is "NO," the process proceeds to step Sa9. That is, in steps Sa1 and Sa2, it is determined whether the cooling temperature T is included in the target cooling range.

[0047] If the determination in step Sa1 is "YES," the process proceeds to step Sa3, and if the determination in step Sa2 is "YES," the process proceeds to step Sa4. In steps Sa3 and Sa4, the control unit 844 determines that the cooling temperature T is inappropriate, i.e., the heating temperature is inappropriate, and controls the amount of heat applied to the seeds by the heating unit 2. In this example, the control unit 844 controls the amount of heat by controlling the second heater 22b.

[0048] Specifically, in step Sa3, the control unit 844 determines that the cooling temperature T is too high, i.e., the heating temperature is too high, and reduces the amount of heating by increasing the proportion of air mixed with the steam in the second heater 22b. In step Sa4, the control unit 844 determines that the cooling temperature T is too low, i.e., the heating temperature is too low, and increases the amount of heating by decreasing the proportion of air mixed with the steam in the second heater 22b. This brings the cooling temperature T closer to the target cooling range.

[0049] In the following step Sa5, the determination unit 843 determines whether the cooling temperature T newly acquired by the acquisition unit 842 falls within the target cooling range within a predetermined time tb. In this example, the predetermined time tb is 30 seconds. That is, in step Sa5, it is determined whether the cooling temperature T has become appropriate as a result of controlling the amount of heating, i.e., whether the heating temperature has become appropriate. If the determination in step Sa5 is "YES," the process returns to step Sa1; if the determination is "NO," the process proceeds to step Sa6.

[0050] In step Sa6, the control unit 844 determines that the cooling temperature T is not appropriate despite controlling the amount of heating, and changes the destination of the seeds to be discharged by the discharge unit 6. Specifically, the control unit 844 switches the destination of the seeds to be discharged from the shipping route 120 to the waiting route 130 by switching the switch 62. As a result, seeds for which the cooling temperature T is not appropriate, i.e., seeds for which the heat sterilization is not appropriate, wait without being shipped.

[0051] In the next step Sa7, the display unit 83 displays a warning that the heat sterilization is not appropriate. That is, the control unit 844 causes the display unit 83 to display a warning that the heat sterilization is not appropriate. In the next step Sa8, the control unit 844 stops the supply of seeds from the supply unit 1 to the heating unit 2. Specifically, the control unit 844 stops the seed supply operation of the tank 12. That is, the operation of the sterilization apparatus 100 is stopped. This completes the processing of the control device 8.

[0052] In step Sa9, the determination unit 843 determines whether or not there are no seeds left in the tank 12. If the determination in step Sa9 is "NO," the process returns to step Sa1. On the other hand, if the determination in step Sa9 is "YES," the process proceeds to step Sa8, where the seed supply operation of the tank 12 is stopped. That is, the operation of the sterilization apparatus 100 is stopped.

[0053] According to the sterilization apparatus 100 configured as above, it is possible to accurately determine whether or not the heat sterilization of seeds is appropriate.

[0054] That is, based on the correlation data 821 between the cooling temperature T and the heating temperature, the control device 8 sets a range of the cooling temperature T corresponding to a predetermined target heating range of the heating temperature as the target cooling range, and determines whether the cooling temperature T is within the target cooling range. Therefore, if the cooling temperature T is within the target cooling range, the heating temperature can also be considered to be within the target heating range, and it can be determined that the heat sterilization by the heating unit 2 is appropriate. On the other hand, if the cooling temperature T is not within the target cooling range, the heating temperature can also be considered to be not within the target heating range, i.e., the heating temperature is too high or too low, and it can be determined that the heat sterilization by the heating unit 2 is not appropriate. In this way, it is possible to accurately determine whether the heat sterilization of seeds is appropriate.

[0055] The sterilization apparatus 100 also includes a front-stage cooling section 3 and a rear-stage cooling section 4, and performs two-stage cooling of heat-sterilized seeds. Therefore, the front-stage cooling section 3 rapidly cools the heat-sterilized seeds to a temperature that does not reduce the germination rate, while the rear-stage cooling section 4 slowly cools the seeds cooled in the front-stage cooling section 3 to a temperature at which they are sufficiently dried. Because the rear-stage cooling section 4 only requires slow cooling, it requires less cooling capacity. Therefore, compared to, for example, rapidly cooling heat-sterilized seeds to a temperature at which they are sufficiently dried, it is possible to reduce the overall required cooling capacity while suppressing a decrease in germination rate. This results in a smaller and less costly sterilization apparatus 100.

[0056] In the sterilization apparatus 100, the temperature of the seeds after cooling by the front-stage cooling unit 3 but before cooling by the rear-stage cooling unit 4 is used as the cooling temperature T. This improves the accuracy of determining whether heat sterilization is appropriate. The seeds after cooling by the front-stage cooling unit 3 have a larger temperature difference from the outside air temperature (i.e., ambient temperature), and therefore have a more unstable temperature and a larger temperature fluctuation range than the seeds after cooling by the rear-stage cooling unit 4. Therefore, it is easier to capture temperature fluctuations in the seeds after cooling by the front-stage cooling unit 3, making it easier to set the target cooling range. Therefore, by using the temperature of the seeds after cooling by the front-stage cooling unit 3 instead of the temperature of the seeds after cooling by the rear-stage cooling unit 4 as the cooling temperature T, it is possible to determine with high accuracy whether heat sterilization is appropriate.

[0057] Furthermore, when the control device 8 determines that the cooling temperature T is not within the target cooling range, it controls the amount of heat applied to the seeds by the heating unit 2 so that the cooling temperature T is within the target cooling range. In other words, if the cooling temperature T is higher than the upper limit value Ta of the target cooling range, the heating temperature is deemed to be too high, and the amount of heat applied to the seeds is reduced. If the cooling temperature T is lower than the lower limit value Tb of the target cooling range, the heating temperature is deemed to be too low, and the amount of heat applied to the seeds is increased. This brings the cooling temperature T into the target cooling range, and thermal sterilization by the heating unit 2 becomes appropriate.

[0058] Furthermore, even if the amount of heat applied to the seeds is controlled, if the cooling temperature T is not within the target cooling range, the control device 8 stops the supply of seeds to the heating unit 2. This makes it possible to reduce the amount of seeds that are inappropriately heat-sterilized.

[0059] Furthermore, if the cooling temperature T is not within the target cooling range even after controlling the amount of heat applied to the seeds, the control device 8 switches the seed discharge destination from the shipping route 120 to the waiting route 130 using the switch 62. Therefore, seeds that have been improperly heat-sterilized are not shipped but are temporarily put on hold. This makes it possible to prevent seeds that have not been properly heat-sterilized from being shipped.

[0060] Furthermore, the heating unit 2 heats the seeds while transporting them by rolling them. In other words, the seeds are heated by steam while rolling. This allows the seeds to be uniformly heat-sterilized. This can suppress unevenness in the heating temperature of the seeds by the heating unit 2, and therefore unevenness in the cooling temperature of the seeds by the pre-cooling unit 3. This increases the uniformity of the cooling temperature T, thereby improving the accuracy of determining whether or not heat-sterilization is appropriate. Furthermore, the seeds are dispersed by rolling, which also allows the seeds to be uniformly heat-sterilized.

[0061] <<Variation>> This modification is a modification of the process of the control device 8 in the above embodiment. When the control device 8 of this modification determines that the cooling temperature T is not within the target cooling range, it immediately switches the seed discharge destination to the standby path 130 by the switch 62 without controlling the amount of heat applied to the seeds by the heating unit 2. Specifically, the control device 8 performs processing according to the flowchart shown in Fig. 5. Fig. 5 is a flowchart showing the process by the control device 8 according to the modification.

[0062] In step Sb1, the determination unit 843 determines whether the cooling temperature T acquired by the acquisition unit 842 is higher than the upper limit value Ta of the target cooling range. More specifically, it determines whether the cooling temperature T has been higher than the upper limit value Ta for a predetermined time tc. In this example, the predetermined time tc is 60 seconds. If the determination in step Sb1 is "NO," the process proceeds to step Sa2. In step Sb2, the determination unit 843 determines whether the cooling temperature T is lower than the lower limit value Tb of the target cooling range. More specifically, it determines whether the cooling temperature T has been lower than the lower limit value Tb for a predetermined time tc. If the determination in step Sb2 is "NO," the process proceeds to step Sb6.

[0063] If the determination in each of step Sb1 and step Sb2 is "YES," the process proceeds to step Sb3. In step Sb3, the control unit 844 determines that the cooling temperature T is inappropriate, i.e., the heating temperature is inappropriate, and changes the destination of the seeds to be discharged by the discharge unit 6. Specifically, the control unit 844 switches the destination of the seeds to be discharged from the shipping route 120 to the waiting route 130 by switching the switch 62, similar to step Sa6 shown in FIG. 4. This allows seeds that are not suitable for heat disinfection to be kept waiting without being shipped.

[0064] The subsequent steps Sb4 and Sb5 are the same as steps Sa7 and Sa8 shown in Fig. 4, respectively. That is, in step Sb4, the display unit 83 displays an alarm indicating that heat sterilization is inappropriate. In step Sb5, the control unit 844 stops the supply of seeds from the supply unit 1 to the heating unit 2. This completes the processing of the control device 8.

[0065] In step Sb6, similar to step Sa9 shown in FIG. 4, the judgment unit 843 judges whether or not there are any seeds left in the tank 12, and if the judgment is "NO", the process returns to step Sb1, and if the judgment is "YES", the process proceeds to step Sb5.

[0066] In this modification, the control device 8 also determines whether the cooling temperature T is within the target cooling range, and therefore can determine whether the heating temperature is within the target heating range, thereby accurately determining whether the seeds are heat-sterilized. Furthermore, if the control device 8 determines that the cooling temperature T is not within the target cooling range, it switches the seed discharge destination to the standby path 130 without controlling the amount of heat, thereby more reliably preventing seeds that are not suitable for heat sterilization from being shipped. Other configurations, actions, and effects are the same as those of the above embodiment.

[0067] Other Embodiments As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology of the present disclosure is not limited to this and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above embodiment can be combined to create new embodiments. Furthermore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately determining that these non-essential components are essential.

[0068] The flowcharts in Figures 4 and 5 are merely examples. Steps in the flowcharts may be changed, replaced, added, omitted, etc. as appropriate. The order of steps in the flowcharts may also be changed, and serial processing may be performed in parallel.

[0069] For example, in steps Sa3 and Sa4 of FIG. 4, the control unit 844 controls the amount of heat applied to the seeds by controlling the second heater 22b. Alternatively, the control unit 844 may control the amount of heat applied to the seeds by controlling the vibrator 24. That is, the control unit 844 may control the amount of heat applied to the seeds by controlling the seed conveying speed. Specifically, in step Sa3, the control unit 844 determines that the heating temperature is too high and controls the vibrator 24 to increase the seed conveying speed. This reduces the amount of heat applied to the seeds. In step Sa4, the control unit 844 determines that the heating temperature is too low and controls the vibrator 24 to decrease the seed conveying speed. This increases the amount of heat applied to the seeds.

[0070] Furthermore, the control unit 844 may control the amount of heat applied to the seeds by controlling the first heater 22a instead of the second heater 22b. That is, the control unit 844 may control the amount of heat applied by controlling the temperature of the air supplied to the second heater 22b. Specifically, in step Sa3, the control unit 844 controls the first heater 22a so that the temperature of the air supplied to the second heater 22b is lowered. This reduces the amount of heat applied to the seeds. In step Sa4, the control unit 844 controls the first heater 22a so that the temperature of the air supplied to the second heater 22b is higher. This increases the amount of heat applied to the seeds.

[0071] In the flowchart of FIG. 4, step Sa6 or step Sa7 may be omitted, or both step Sa6 and step Sa7 may be omitted.

[0072] 5, step Sb3 may be omitted, or both step Sb3 and step Sa4 may be omitted. That is, when the control device 8 determines that the cooling temperature T is not within the target cooling range, it may immediately stop the supply of seeds to the heating unit 2, that is, stop the operation of the sterilization apparatus 100, without changing the destination of the seeds discharged by the discharge unit 6.

[0073] In addition, in the flowchart of FIG. 5, step Sb4 may be omitted.

[0074] Also, step Sa8 may be omitted from the flowchart of Fig. 4. Step Sb5 may be omitted from the flowchart of Fig. 5.

[0075] In addition, in the flowchart of Fig. 4, steps Sa6 to Sa8 may be performed in parallel with each other, and in the flowchart of Fig. 5, steps Sb3 to Sb5 may be performed in parallel with each other.

[0076] Furthermore, the values ​​of the predetermined times ta, tb, and tc described above are merely examples and can be set arbitrarily.

[0077] Furthermore, as shown in FIG. 6, the front-stage cooling section 3 and the rear-stage cooling section 4 may have a single common trough 36 instead of separate troughs 31, 41. FIG. 6 is a plan view showing the trough 36 of the front-stage cooling section 3 and the rear-stage cooling section 4 according to another embodiment. The trough 36 is formed as a long plate extending substantially horizontally and has a first ventilation section 36a, a second ventilation section 36b, a non-ventilation section 36c, and a third ventilation section 36d, which are divided in order in the longitudinal direction. That is, in the trough 36, the seeds are transported in the order of the first ventilation section 36a, the second ventilation section 36b, the non-ventilation section 36c, and the third ventilation section 36d. The first ventilation section 36a and the second ventilation section 36b are regions of the front-stage cooling section 3, and the third ventilation section 36d is a region of the rear-stage cooling section 4. The non-ventilation section 36c is a common area for the front-stage cooling section 3 and the rear-stage cooling section 4. The temperature sensor 5 is provided above the non-ventilation section 36c. As in the above embodiment, the seeds are cooled by the vertical passage of cool air through each of the first ventilation section 36a, the second ventilation section 36b, and the third ventilation section 36d. With this configuration of the trough 36, the vertical installation space for the cooling sections 3 and 4 is reduced.

[0078] Furthermore, the heating section 2 and the cooling sections 3 and 4 may be configured to transport the seeds without rolling them.

[0079] Also, the rear-stage cooling section 4 may be omitted. That is, the seeds may be cooled to a temperature at which they are sufficiently dried by the front-stage cooling section 3 (cooling section). [Industrial Applicability]

[0080] As described above, the present invention is useful for a seed disinfection device. [Explanation of symbols]

[0081] 100 Disinfection equipment 120 Shipping Routes 130 Waiting Route 2 Heating section 3 Front cooling section (cooling section) 4. Post-cooling section 5 Temperature Sensor 8 Control Device T cooling temperature Ta upper limit (target cooling range) Tb lower limit (target cooling range)

Claims

1. a heating unit that heats and sterilizes seeds with steam; A cooling unit that cools the seeds after heating by the heating unit; a temperature sensor for detecting a cooling temperature, which is the temperature of the seeds after cooling by the cooling unit; a control device that sets a range of the cooling temperature corresponding to a predetermined target heating range of the heating temperature as a target cooling range based on a correlation between the cooling temperature and a heating temperature, which is the temperature of the seeds after heating by the heating unit, according to the cooling capacity of the cooling unit, and determines whether the cooling temperature detected by the temperature sensor is included in the target cooling range. A seed disinfection device characterized by:

2. 2. The seed disinfection device according to claim 1, The cooling unit includes a front-stage cooling unit as the cooling unit, and further includes a rear-stage cooling unit that further cools the seeds after cooling by the front-stage cooling unit, The cooling temperature is the temperature of the seeds after cooling by the front-stage cooling section and before cooling by the rear-stage cooling section. A seed disinfection device characterized by:

3. 2. The seed disinfection device according to claim 1, When the control device determines that the cooling temperature detected by the temperature sensor is not within the target cooling range, the control device controls the amount of heat applied to the seeds by the heating unit so that the cooling temperature detected by the temperature sensor is within the target cooling range. A seed disinfection device characterized by:

4. 2. The seed disinfection device according to claim 1, When the control device determines that the cooling temperature detected by the temperature sensor is not within the cooling target range, the control device stops supplying seeds to the heating unit. A seed disinfection device characterized by:

5. 2. The seed disinfection device according to claim 1, The cooling system further includes a switch for switching between a shipping route for shipping the seeds and a waiting route for temporarily waiting the seeds as a destination for discharging the seeds after cooling by the cooling unit, When the control device determines that the cooling temperature detected by the temperature sensor is not within the cooling target range, the control device switches to the standby path by the switch. A seed disinfection device characterized by:

6. 2. The seed disinfection device according to claim 1, The heating unit heats the seeds while transporting them by rolling them. A seed disinfection device characterized by:

Images