Circulating grain dryer

Abstract

To provide a circulation type grain dryer in which the workability of sample collection is improved.SOLUTION: A circulation type grain dryer comprises: a storage chamber; a drying part; a supply device; a lifting device; a sample take-out part which is provided between the supply device and the lifting device or in a base part of the lifting device; and a controller which is configured to control the supply device in the operation mode selected from a sample collection mode for taking out grain as a sample from the sample take-out part and a normal mode that does not take out the grain from the sample take-out part. The controller is configured to control the supply device such that the supply device intermittently operates in a first operation pattern in the normal mode and the supply device continuously or intermittently operates in a second operation pattern in the sample collection mode. The operation rate of the supply device in the second operation pattern is larger than the operation rate of the supply device in the first operation pattern.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a circulation type grain dryer. [Background technology]

[0002] Circulation-type grain dryers that dry grain while circulating it are known. For example, Patent Document 1 below discloses a circulation-type grain dryer that includes a storage chamber for storing grain, a drying section located below the storage chamber, a rotary valve for discharging grain from the drying section, and an elevator for transporting the grain discharged by the rotary valve back to the storage chamber. The rotary valve operates continuously when the grain moisture content is high, and operates intermittently at predetermined intervals when the grain moisture content drops to a predetermined level. This configuration can suppress fluctuations in the amount of grain delivered by the rotary valve, which would occur if the grain bulk density increased as the moisture content decreased due to drying.

[0003] In this type of circulation type grain dryer, there is a demand for taking a sample of the grain during the drying process at the end of the drying operation, and the user can measure the moisture content of the sample to confirm that the moisture content of the grain has been reduced to the desired level. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-133792 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-described circulation-type grain dryer leaves room for improvement in terms of sample collection. Specifically, in the above-described circulation-type grain dryer, the rotary valve operates intermittently during the final stage of drying operation. Therefore, if a sufficient amount of sample cannot be collected while the rotary valve is operating, the user must wait for an interval and resume sample collection when the rotary valve operates again. Typically, such an interval is relatively long (e.g., 40 seconds), which makes sample collection difficult. This problem is also common to circulation-type grain dryers in which the rotary valve is always operated intermittently. For these reasons, it is desirable to provide a circulation-type grain dryer with improved sample collection efficiency. [Means for solving the problem]

[0006] The present invention has been made to solve the above-mentioned problems, and can be realized, for example, in the following forms.

[0007] According to a first aspect of the present invention, there is provided a circulating grain dryer comprising: a storage chamber for storing grain; a drying section disposed below the storage chamber and configured to dry the grain; a feeder configured to discharge the grain from the drying section; a lifting device configured to transport the grain discharged by the feeder for returning the grain to the storage chamber; a sample removal section disposed between the feeder and the lifting device or at the base of the lifting device; and a controller configured to control the feeder in an operation mode selected from a sample collection mode for removing grain samples from the sample removal section and a normal mode in which no grain is removed from the sample removal section. The controller is configured to control the feeder so that in the normal mode, the feeder operates intermittently in a first operation pattern and so that in the sample collection mode, the feeder operates continuously or intermittently in a second operation pattern. The operation rate of the feeder in the second operation pattern is greater than the operation rate of the feeder in the first operation pattern.

[0008] In this circulation type grain dryer, the supply device operates at a higher operating rate in the sample collection mode than in the normal mode, allowing samples to be collected more efficiently. This improves the workability of sample collection. For example, if the operation period of the supply device is longer in the sample collection mode than in the normal mode, more grain is delivered during the operation period, increasing the likelihood that the required amount of samples can be collected during that operation period. Alternatively, if the interval between operation periods of the supply device is shorter in the sample collection mode than in the normal mode, even if the required amount of samples cannot be collected during the operation period, the waiting time between intervals to collect the required amount of samples will be shorter.

[0009] According to a second aspect of the present invention, in the first aspect, the second operation pattern has a shorter interval between operation periods of the supply device than the first operation pattern. According to this aspect, even if the required amount of samples cannot be collected during one operation period, the waiting time due to the interval to collect the required amount of samples is shortened.

[0010] According to a third aspect of the present invention, there is provided a circulating grain dryer comprising: a storage chamber for storing grain; a drying section disposed below the storage chamber and configured to dry the grain; a feeder configured to discharge the grain from the drying section; a lifting device configured to transport the grain discharged by the feeder for returning the grain to the storage chamber; a sample removal section disposed between the feeder and the lifting device or at the base of the lifting device; and a controller configured to selectively control the feeder in an operation mode selected from a sample collection mode for removing grain as a sample from the sample removal section and a normal mode in which no grain is removed from the sample removal section. The controller is configured to control the feeder so that in the normal mode, the feeder operates continuously or intermittently in a first operation pattern selected from at least two predetermined operation pattern candidates, and so that in the sample collection mode, the feeder operates continuously or intermittently in a second operation pattern. The operation rate of the supply device in the second operation pattern is greater than the smallest operation rate among the operation rates of at least two predetermined operation pattern candidates.

[0011] In this circulation type grain dryer, in the sample collection mode, the supply device operates at an operating rate greater than the smallest operating rate among at least two predetermined operation pattern candidates, allowing samples to be collected more efficiently than when samples are collected when the supply device is operating at the smallest operating rate. In other words, sampling under conditions that are least efficient for work can be avoided, thereby improving the efficiency of sample collection.

[0012] According to a fourth aspect of the present invention, in the third aspect, the second operation pattern has a shorter interval between operation periods of the supply device than an operation pattern with the smallest operation rate among at least two predetermined operation pattern candidates. According to this aspect, even if the required amount of samples cannot be collected during one operation period, the waiting time due to the interval for collecting the required amount of samples is shortened.

[0013] According to a fifth aspect of the present invention, in the third or fourth aspect, the supply device operates intermittently in normal mode. The operation rate of the supply device in the second operation pattern is the same as the largest operation rate among the operation rates of at least two predetermined operation pattern candidates. According to this aspect, samples can be collected with the same efficiency as the operation pattern that allows most efficient sample collection in normal mode. In other words, samples can be collected as efficiently as possible without placing a greater load on the supply device than in normal mode.

[0014] According to a sixth aspect of the present invention, in the third to fifth aspects, the controller is configured to prohibit switching of the operation mode from the normal mode to the sample collection mode when controlling the normal mode at an operation rate higher than the operation rate of the supply device in the second operation pattern. According to this aspect, the operation rate of the supply device does not decrease as a result of switching the operation mode from the normal mode to the sample collection mode.

[0015] According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the supply device is in the form of a rotary valve. This aspect ensures high load-bearing capacity for the grain in the storage chamber and the drying section while achieving high quantitative supply performance.

[0016] According to an eighth aspect of the present invention, the circulating grain dryer of any one of the first to seventh aspects further includes a user interface configured to accept input of an instruction to operate in sample collection mode. The controller is configured to switch the operating mode from the normal mode to the sample collection mode when the instruction is accepted via the user interface, and to return the operating mode from the sample collection mode to the normal mode when a predetermined time has elapsed in the sample collection mode. This aspect simplifies the user's operation of the circulation grain dryer when collecting samples. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an external perspective view of a circulation type grain dryer according to one embodiment. FIG. [Figure 2] FIG. 2 is a diagram showing a schematic internal structure of a circulation type grain dryer. [Figure 3] This is an enlarged view of the sample extraction section and its vicinity, with some parts removed. [Figure 4] FIG. [Figure 5] FIG. 10 is a diagram showing an example of an operation pattern of the rotary valve in a normal mode. [Figure 6] FIG. 10 is a diagram showing an example of an operation pattern of a rotary valve in a sample collection mode. [Figure 7] FIG. 10 is a diagram showing another example of the operation pattern of the rotary valve in the sample collection mode. DETAILED DESCRIPTION OF THE INVENTION

[0018] FIG. 1 is an external perspective view of a circulation-type grain dryer 10 (hereinafter also simply referred to as the dryer 10) according to one embodiment. FIG. 2 is a diagram showing a schematic internal structure of the dryer 10. As shown in FIG. 1, the dryer 10 includes a storage chamber 20 for storing grain, a drying section 30 disposed below the storage chamber 20 and configured to dry the grain, and an elevator device 60. As shown in FIG. 2, the drying section 30 includes a hot air chamber 31, grain flow-down chambers 32 and 33, and an air exhaust chamber 34. Hot air generated by a combustion burner (not shown) is blown into the hot air chamber 31. The grain flow-down chambers 32 and 33 are vertically connected to the storage chamber 20 and extend downward in an elongated manner on both sides of the hot air chamber 31. The air exhaust chamber 34 is located outside the grain flow-down chambers 32 and 33. The hot air flowing through the hot air chamber 31 is guided by the action of a suction fan (not shown) through small holes in the casing that forms the grain flow-down chambers 32, 33, through the grain flow-down chambers 32, 33, and into the air exhaust chamber 34. At this time, the hot air comes into contact with the grain in the grain flow-down chambers 32, 33, drying the surface of the grain.

[0019] As shown in FIG. 2, a rotary valve 40, which is an example of a supply device for discharging grain from the drying section 30, is disposed at the lower end of the grain flow-down chambers 32, 33. The rotary valve 40 discharges grain downward from the drying section 30. Specifically, the rotary valve 40 has a cylindrical shape, and its interior functions as a storage chamber for storing grain. An opening 41 is formed in its outer circumferential surface, thereby forming a C-shaped opening in a portion of the circumferential direction. The rotary valve 40 is configured to be rotatable forward and backward by a motor (not shown). In its initial position, the rotary valve 40 is oriented so that the opening 41 faces downward, as shown in FIG. 2.

[0020] When the rotary valve 40 rotates forward (clockwise in FIG. 2) from the initial position, the opening 41 of the rotary valve 40 and the grain flow-down chamber 33 communicate with each other, and the grain in the grain flow-down chamber 33 flows into the rotary valve 40, filling the rotary valve 40 with grain. When the rotary valve 40 rotates further and returns to the initial position, the grain inside the rotary valve 40 falls from the opening 41 and is sent downward (to the bottom of the air exhaust chamber 34).

[0021] When the rotary valve 40 rotates in the reverse direction (counterclockwise in FIG. 2) from the initial position, the opening 41 of the rotary valve 40 and the grain flow-down chamber 32 communicate with each other, and the grain in the grain flow-down chamber 32 flows into the rotary valve 40, filling the rotary valve 40 with grain. When the rotary valve 40 rotates further and returns to the initial position, the grain inside the rotary valve 40 falls from the opening 41 and is sent downward (to the bottom of the air exhaust chamber 34).

[0022] The rotary valve 40 ensures high load-bearing capacity for the grain in the storage chamber 20 and the drying section 30 while providing high fixed-quantity supply performance. However, any supply device may be used instead of the rotary valve 40. For example, the supply device may be a gate-opening / closing type.

[0023] As shown in FIG. 2, a lower screw conveyor 50 is disposed at the bottom of the air exhaust chamber 34. The lower screw conveyor 50 transports the grain discharged by the rotary valve 40 horizontally to the lifting device 60. As shown in FIG. 1, the lifting device 60 is in the form of a bucket conveyor and is disposed so as to extend vertically. The lifting device 60 transports the grain upward after drying in the drying section 30 to return the grain to the storage chamber 20. The grain transported to near the top of the dryer 10 by the lifting device 60 is transported to the storage chamber 20 by an upper screw conveyor (not shown). The grain returned to the storage chamber 20 with its surface dried is further dried by the tempering action within the storage chamber 20.

[0024] With this configuration, grain fed from loading hopper 21 (see Figure 1) into drying section 30 passes through lower screw conveyor 50, lifting device 60, storage chamber 20, and drying section 30 before entering rotary valve 40. When rotary valve 40 rotates, the grain returns to lower screw conveyor 50 and is then circulated along this route until it is dried to a predetermined moisture content and then discharged outside the machine through discharge port 22.

[0025] A sample extraction unit 70 is provided at the base of the lifting device 60 so that the user can collect samples for purposes such as moisture measurement. FIG. 3 is an enlarged view of the vicinity of the sample extraction unit 70, with some parts removed. FIG. 4 is an exploded perspective view of the sample extraction unit 70. As shown in FIG. 3, the sample extraction unit 70 is attached to a cover 61 of the lifting device 60. The cover 61 is disposed so as to face a bucket (not shown) of the lifting device 60, and covers the interior of the lifting device 60. As shown in FIG. 4, the cover 61 has a long hole 62 formed therein, which connects the interior and exterior of the lifting device 60.

[0026] As shown in FIG. 4, the sample extraction section 70 includes a slide member 71 and a holding member 75. The slide member 71 is a box-shaped member with its longitudinal direction extending vertically. The slide member 71 includes a chute 72 located at its lower end, an engagement portion 73 located at its upper end, and an elongated hole 74 located between the chute 72 and the engagement portion 73. The engagement portion 73 protrudes in a direction away from the cover 61. The elongated hole 74 penetrates the box-shaped bottom surface of the slide member 71 in the horizontal direction.

[0027] 4, the holding member 75 includes a main body 76 having a bent shape such that a rectangular groove extends vertically, and a stopper 77. The stopper 77 extends from the upper edge of the main body 76 (the portion that forms the bottom of the rectangular groove) toward the cover 61. A gap is formed between the portion of the main body 76 that forms the bottom of the rectangular groove and the stopper 77 so that the slide member 71 can fit into it.

[0028] 3, the sample extraction section 70 is attached to the cover 61 by fitting the slide member 71 into the groove of the holding member 75 and then screwing the holding member 75 to the cover 61. At this time, the slide member 71 is held by the holding member 75 in a state where it can slide up and down relative to the holding member 75.

[0029] In its initial position, the slide member 71 is held with the engagement portion 73 resting on the stopper 77 (see FIG. 3). At this time, the elongated hole 62 of the cover 61 and the elongated hole 74 of the slide member 71 are not in communication with each other. On the other hand, when a user grasps the slide member 71 by hand and slides it upward, the elongated holes 62 and 74 align and communicate with each other (see FIG. 4). In other words, the interior and exterior of the lifting device 60 are in communication with each other via the elongated holes 62 and 74. When the user grasps the slide member 71 by hand and slides it upward while grain is being transported by the lower screw conveyor 50 and the lifting device 60, the elongated holes 62 and 74 communicate with each other, and some of the grain scooped up by the bucket of the lifting device 60 is blown out of the lifting device 60 through the elongated holes 62 and 74 and discharged through the chute 72. If a user places a container below the chute 72, the user can collect grain as a sample in the container.

[0030] Any structure for collecting samples may be employed in place of the above-described sample removal section 70. For example, in an alternative embodiment, the sample removal section may be provided between the rotary valve 40 and the lifting device 60 (in other words, on the side of the lower screw conveyor 50). In this case, some of the grains thrown to the side by the lower screw conveyor 50 may be discharged through the hole in the sample removal section.

[0031] 1, the dryer 10 further includes a controller 80 and an operation panel 81 as an example of a user interface. The controller 80 controls the operation of the rotary valve 40 and also controls the overall operation of the dryer 10. The functions of the controller 80 may be realized by a CPU executing a predetermined program stored in a memory, or may be realized by a dedicated circuit, or may be realized by a combination of these.

[0032] The control of the rotary valve 40 by the controller 80 will be described below. In this embodiment, the controller 80 constantly operates the lower screw conveyor 50 and the lifting device 60 using the rotational drive force of a single motor (not shown). On the other hand, the controller 80 controls the rotary valve 40 to operate intermittently. Specifically, the controller 80 controls the rotary valve 40 in an operation mode selected from a sample collection mode for extracting grain as a sample from the sample extraction section 70, and a normal mode in which no grain is extracted from the sample extraction section 70.

[0033] In the normal mode, the controller 80 controls the rotary valve 40 to operate intermittently in a first operation pattern. In the sample collection mode, the controller 80 controls the rotary valve 40 to operate intermittently in a second operation pattern. Figure 5 shows an example of the first operation pattern. Figure 6 shows an example of the second operation pattern.

[0034] In the first operation pattern shown in Fig. 5, a forward rotation operation period T11 during which the rotary valve 40 rotates in the forward direction, an interval period T12 during which the rotary valve 40 stops, and a reverse operation period T13 during which the rotary valve 40 rotates in the reverse direction are repeated in the order of T11, T12, T13, T12. Similarly, in the second operation pattern shown in Fig. 6, a forward rotation operation period T21, an interval period T22, and a reverse operation period T23 are repeated in the order of T21, T22, T23, T22. The rotary valve 40 rotates once during each of the forward rotation operation periods T11, T21 and the reverse operation periods T13, T23. The operating rate of the rotary valve 40 in the first operating pattern is calculated by (T11+T13) / (T11+T12+T13+T12), and the operating rate of the rotary valve 40 in the second operating pattern is calculated by (T21+T23) / (T21+T22+T23+T22).

[0035] Comparing the first and second operation patterns, T11 = T21, T13 = T23, and T12 > T22. Therefore, the operation rate in the second operation pattern is greater than that in the first operation pattern. In one embodiment, T11 = T21 = T13 = T23 = 7 seconds, T12 = 40 seconds, and T22 = 5 seconds.

[0036] According to this control, the operation rate of the rotary valve 40 in the sample collection mode is greater than the operation rate of the rotary valve 40 in the normal mode, and therefore the amount of grain delivered from the rotary valve 40 per unit time is greater in the sample collection mode than in the normal mode. This allows the user to collect samples more efficiently. In particular, in this example, the interval period T22 in the sample collection mode is shorter than the interval period T12 in the normal mode. Therefore, even if the required amount of sample is not collected by the delivery of grain by the rotary valve 40 during the initial forward rotation operation period T21, the waiting time for collecting the shortfall during the subsequent reverse rotation operation period T23 or forward rotation operation period T21 is shorter. This improves the workability of sample collection compared to when sampling is performed in the normal mode.

[0037] In this embodiment, control by the controller 80 in the sample collection mode is initiated when the controller 80 receives an instruction to operate in the sample collection mode input by the user via the operation panel 81. In all other cases, the controller 80 controls the rotary valve 40 in the normal mode.

[0038] In one embodiment, the controller 80 returns the operation mode from the sample collection mode to the normal mode when the time spent in the sample collection mode reaches a predetermined time. For example, the controller 80 may return the operation mode from the sample collection mode to the normal mode when one cycle consisting of T21, T22, T23, and T22 is repeated five times. This configuration simplifies user operations because the user does not need to perform any operation to terminate the sample collection mode. However, the operation mode may also be returned to the normal mode when the controller 80 receives an instruction from the user via the operation panel 81 to operate in the normal mode.

[0039] In an alternative embodiment, the dryer 10 may include a sensor that optically, magnetically, electrically, or mechanically detects that the slide member 71 has been slid from its initial position. In this case, the controller 80 may switch the operation mode from the normal mode to the sample collection mode when it detects that the slide member 71 has been slid from its initial position. Furthermore, the controller 80 may return the operation mode from the sample collection mode to the normal mode when it detects that the slide member 71 has returned to its initial position. This configuration further simplifies the user's operation for sample collection.

[0040] 7 shows another example of the second operation pattern for the sample collection mode. In this example, as in the example of FIG. 6, a forward rotation operation period T31, an interval period T32, and a reverse rotation operation period T33 are repeated in the order of T31, T32, T33, and T32. However, in this example, T31 = T33 = 2 × T11 = 2 × T13. That is, the rotary valve 40 makes two consecutive rotations during each of the forward rotation operation period T31 and the reverse rotation operation period T3.

[0041] In this way, if one operation period is set longer than in the normal mode (the number of continuous rotations is increased), more grain will be sent out by the rotary valve 40 during one operation period, increasing the likelihood that the required amount of samples will be collected during that one operation period. Furthermore, in the example of FIG. 7, since T12>T32, the waiting time for collecting the shortage is also shortened, as in FIG. 6. In other words, in the example of FIG. 7, by setting one operation period longer than in the normal mode (the number of continuous rotations is increased) and setting the interval period shorter than in the normal actual mode, the operation rate of the second operation pattern is set higher than the operation rate of the first operation pattern.

[0042] In an alternative embodiment, the operation rate of the second operation pattern may be set to be greater than the operation rate of the first operation pattern simply by setting one operation period longer (more continuous rotations) than in the normal mode.

[0043] In a further alternative embodiment, at least two operation patterns may be predetermined for the normal mode. In this case, the at least two operation patterns are set so that the operation rates of the rotary valve 40 differ from one another. In other words, the at least two operation patterns are set so that at least one of the length of an operation period (number of continuous rotations) of each of the forward and reverse rotations of the rotary valve 40 and the length of the interval period (including the case where there is no interval) differs from one another. In the normal mode, the controller 80 selects one operation pattern from the at least two operation patterns as a first operation pattern depending on the processing conditions and / or the progress of the drying process, and controls the rotary valve 40 based on the first operation pattern.

[0044] In this alternative embodiment, the controller 80 controls the rotary valve 40 so that, in the sample collection mode, the rotary valve 40 operates continuously or intermittently in a second operation pattern. In this case, the operation rate of the second operation pattern is set to be greater than the smallest operation rate among the operation rates of the at least two operation patterns for the normal mode. This configuration makes it possible to avoid inefficient sample collection when the rotary valve 40 operates in the operation pattern for the normal mode with the smallest operation rate. In this alternative embodiment, the interval period of the second operation pattern may also be set to be shorter than the interval period of the operation pattern with the smallest operation rate.

[0045] In this alternative embodiment, each of the at least two operating patterns for the normal mode may be a pattern in which the rotary valve 40 is operated intermittently. In this case, the operating rate of the second operating pattern may be the same as the largest operating rate of the at least two operating patterns for the normal mode. This configuration allows samples to be collected with the same efficiency as the operating pattern in the normal mode that allows samples to be collected most efficiently. In other words, samples can be collected as efficiently as possible without imposing a greater load on the rotary valve 40 than in the normal mode.

[0046] Alternatively, when at least two operation patterns are predefined for the normal mode, the operation rate of the second operation pattern may be set to be lower than the largest operation rate among the at least two operation patterns for the normal mode. In this case, the controller 80 may prohibit switching the operation mode from the normal mode to the sample collection mode when controlling the normal mode with an operation rate higher than the operation rate of the second operation pattern. This configuration prevents a decrease in the operation rate of the rotary valve 40 as a result of switching the operation mode from the normal mode to the sample collection mode.

[0047] Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. Furthermore, any combination or omission of the components described in the claims and specification is possible within the scope of solving at least part of the above-described problems or achieving at least part of the effects.

[0048] For example, the various operation patterns described above are merely examples and can be changed as appropriate. [Explanation of symbols]

[0049] 10...Circulating grain dryer 20...Storage chamber 21...Stakeout Hopper 22...Exhaust port 30...Drying section 31...Hot air chamber 32,33...Grain flow chamber 34...Exhaust room 40...Rotary valve 41...Aperture 50...Lower screw conveyor 60...Lifting device 61...Cover 62...long hole 70...Sample extraction section 71...Slide member 72...Shoot 73...Engagement part 74...long hole 75...Retaining member 76...Main body 77...Stopper 80...Controller 81...Operation panel

Claims

1. A circulation type grain dryer, a storage chamber for storing grain; a drying section provided below the storage chamber and configured to dry the grain; a feeder configured to deliver the grain from the drying section; a lifting device configured to transport the grain delivered by the feeder back to the storage chamber; a sample take-out unit provided between the supply device and the lifting device or at a base of the lifting device; a controller configured to control the feeding device in an operational mode selected from a sampling mode for removing the grain as a sample from the sample removal unit and a normal mode for not removing the grain from the sample removal unit; a user interface configured to accept input of instructions for operating in the sample collection mode; Equipped with The controller In the normal mode, the supply device operates intermittently in a first operating pattern; In the sample collection mode, the supply device is configured to operate continuously or intermittently in a second operating pattern. configured to control the supply device; an operation rate of the supply device in the second operation pattern is greater than an operation rate of the supply device in the first operation pattern; The controller is configured to switch the operation mode from the normal mode to the sample collection mode when receiving the instruction input via the user interface, and to return the operation mode from the sample collection mode to the normal mode when a stay time in the sample collection mode reaches a predetermined time. Circulating grain dryer.

2. The circulation type grain dryer according to claim 1, The second operation pattern has a shorter interval between operation periods of the supply device than the first operation pattern. Circulating grain dryer.

3. A circulation type grain dryer, a storage chamber for storing grain; a drying section provided below the storage chamber and configured to dry the grain; a feeder configured to deliver the grain from the drying section; a lifting device configured to transport the grain delivered by the feeder back to the storage chamber; a sample take-out unit provided between the supply device and the lifting device or at a base of the lifting device; a controller configured to selectively control the feeding device in an operating mode selected from a sampling mode for removing the grain as a sample from the sample removal unit and a normal mode for not removing the grain from the sample removal unit; Equipped with The controller In the normal mode, the supply device operates continuously or intermittently in a first operation pattern selected from at least two predetermined operation pattern candidates; In the sample collection mode, the supply device is configured to operate continuously or intermittently in a second operating pattern. configured to control the supply device; The operation rate of the supply device in the second operation pattern is greater than the smallest operation rate among the operation rates of the at least two predetermined operation pattern candidates, and is equal to or less than the largest operation rate among the operation rates of the at least two predetermined operation pattern candidates. Circulating grain dryer.

4. The circulation type grain dryer according to claim 3, The second operation pattern has an interval of an operation period of the supply device that is shorter than an operation pattern having the smallest operation rate among the at least two predetermined operation pattern candidates. Circulating grain dryer.

5. The circulation type grain dryer according to claim 3 or claim 4, In the normal mode, the supply device operates intermittently; The operation rate of the supply device in the second operation pattern is the same as the largest operation rate among the operation rates of the at least two predetermined operation pattern candidates. Circulating grain dryer.

6. The circulation type grain dryer according to any one of claims 1 to 5, The delivery device is in the form of a rotary valve Circulating grain dryer.

7. A circulation type grain dryer, a storage chamber for storing grain; a drying section provided below the storage chamber and configured to dry the grain; a feeder configured to deliver the grain from the drying section; a lifting device configured to transport the grain delivered by the feeder back to the storage chamber; a sample take-out unit provided between the supply device and the lifting device or at a base of the lifting device; a controller configured to selectively control the feeding device in an operating mode selected from a sampling mode for removing the grain as a sample from the sample removal unit and a normal mode for not removing the grain from the sample removal unit; Equipped with The controller In the normal mode, the supply device operates continuously or intermittently in a first operation pattern selected from at least two predetermined operation pattern candidates; In the sample collection mode, the supply device is configured to operate continuously or intermittently in a second operating pattern. configured to control the supply device; an operation rate of the supply device in the second operation pattern is greater than the smallest operation rate among the operation rates of the at least two predetermined operation pattern candidates; The controller is configured to prohibit switching of the operation mode from the normal mode to the sample collection mode when controlling the normal mode at an operation rate greater than an operation rate of the supply device in the second operation pattern. Circulating grain dryer.

8. A circulation type grain dryer, a storage chamber for storing grain; a drying section provided below the storage chamber and configured to dry the grain; a feeder configured to deliver the grain from the drying section; a lifting device configured to transport the grain delivered by the feeder back to the storage chamber; a sample take-out unit provided between the supply device and the lifting device or at a base of the lifting device; a controller configured to selectively control the feeding device in an operating mode selected from a sampling mode for removing the grain as a sample from the sample removal unit and a normal mode for not removing the grain from the sample removal unit; a user interface configured to accept input of instructions for operating in the sample collection mode; Equipped with The controller In the normal mode, the supply device operates continuously or intermittently in a first operation pattern selected from at least two predetermined operation pattern candidates; In the sample collection mode, the supply device is configured to operate continuously or intermittently in a second operating pattern. configured to control the supply device; an operation rate of the supply device in the second operation pattern is greater than the smallest operation rate among the operation rates of the at least two predetermined operation pattern candidates; The controller is configured to switch the operation mode from the normal mode to the sample collection mode when receiving the instruction input via the user interface, and to return the operation mode from the sample collection mode to the normal mode when a stay time in the sample collection mode reaches a predetermined time. Circulating grain dryer.

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