Grain dryer

Abstract

To provide energy-saving drying control of high drying efficiency, combining airflow drying and hot-air drying.SOLUTION: Airflow drying that performs drying using an airflow, carries out drying with little damage to grain and excellent drying efficiency, by controlling the grain circulation according to the ambient temperature and the moisture in the grain. When it is determined that the hot-air drying is more efficient than the airflow drying according to the ambient temperature, the moisture in the grain, the temperature of the grain and the like upon switching to the hot air drying from the airflow drying, the switching is carried out with the drying temperature setting being set at an efficient lower-temperature setting to perform energy-saving drying control.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] When grain dryers are used, energy-saving drying is possible by simply passing air through the grain when the grain has a high moisture content. Compared to hot air drying, this method has the advantage of lowering production costs because it can dry grains without using fuel for combustion. Furthermore, there is an energy-saving drying method that automatically switches to hot air drying when the moisture content decreases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2014-214890 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, as an energy-saving measure, drying operation using ventilation is initiated when the moisture content of the grain is above a predetermined value, and drying using hot air is initiated when the moisture content falls below the predetermined value. However, when drying using ventilation, the drying speed is slow and the overall drying time is long. The longer the circulation time of the grain inside the dryer, the greater the damage to the grain. The objective of this project is to enable energy-saving drying by drying while minimizing damage to the grain when drying is possible using ventilation alone, given the outside air temperature and grain moisture. [Means for solving the problem]

[0005] The invention of claim 1 is solved by the following technical means.

[0006] The dryer is equipped with sensors for detecting the outside air temperature, exhaust air temperature, and grain temperature, a moisture meter (29) for detecting the moisture content of the grain, a rotary valve (15) for feeding the grain to circulate it in the dryer, and a combustion burner (28) for performing hot air drying operation to dry the grain. The dryer is capable of selecting between normal hot air drying operation and energy-saving drying operation, and when the energy-saving drying mode (40) is selected, the outside air temperature is higher than a predetermined value and the grain moisture content is higher than a predetermined value. The grain temperature is higher than the specified value. In this case, the combustion burner is stopped and ventilation is continuously performed to blow air into the drying section, and the grain circulation is also performed. Intermittent operation It is characterized by:

[0007] The invention of claim 2 is solved by the following technical means.

[0008] When the temperature of the exhaust air or the grain reaches the temperature of the outside air, the circulation of the grain is switched from the intermittent operation to a continuous operation.

[0009] The invention of claim 3 is solved by the following technical means.

[0010] When drying is started in the energy-saving drying mode, the intermittent time of grain circulation during ventilation drying is changed depending on the grain variety.

[0011]

[0012]

[0013]

[0014] [Effects of the Invention]

[0015] The inventions of claims 1 and 2 reduce damage to grains caused by ventilation drying and enable efficient ventilation drying.

[0016]

[0017] Claim 3 This invention makes it possible to efficiently dry crops by utilizing the ease of drying of different varieties.

[0018] [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a front view of an external appearance of a grain dryer according to an embodiment of the present invention. [Figure 2] A perspective view of the grain dryer [Figure 3] FIG. 1 shows the inside of the grain dryer as seen from the front. [Figure 4] Energy-saving drying, intermittent circulation ventilation drying control flow chart [Figure 5] Flowchart of interval control for intermittent circulation by grain type [Figure 6] Flowchart of temperature settings when switching to hot air drying for energy-saving drying [Figure 7] A diagram explaining how weight is displayed in a weight measurement display [Figure 8] A diagram explaining the screen displaying daily weight management in the weight measurement display. [Figure 9] A diagram explaining the screen that displays the weight ratio of individual loading amounts in the weight measurement display. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described below with reference to the embodiments shown in the drawings.

[0021] As shown in Figures 1, 2, and 3, the box-shaped tank (T) for storing grain as an example of a crop contains a storage section (1), a drying section (2) for drying the grain, and a grain collection section (3) for collecting grain that has passed through the drying section (2). The tank (T) is composed of an upper panel (J) that forms the storage section (1), a middle panel (C) that forms the drying section (2), and a base section (D) that forms the grain collection section (3).

[0022] The drying section (2) is provided with a hot air chamber (5) through which hot air generated by a combustion burner (28) in a burner case (4) passes, a grain flow-down chamber (6) through which grain flows down, and an exhaust air chamber (8) through which the hot air that has passed from the hot air chamber (5) through the grain flow-down chamber (6) passes as exhaust air by suction of an exhaust fan (7).

[0023] A rotary valve (15) is provided at the lower end of the grain flow-down chamber (6) to deliver the grain to the grain collection section (3), and the grain collection section (3) is provided with a lower spiral (9) to transport the grain and an inclined plate (10) to guide the grain to the lower spiral (9).

[0024] As shown in Figure 2, in front of the tank (T) are an elevator (11) that lifts the grain transported by the lower spiral (9), a burner case (4), and an operation panel (16) that houses the control unit. The operation panel (16) is equipped with various switches and setting switches required for drying operation and control, and an LCD display (18) that displays the drying progress status, etc. An upper spiral (12) that transports the grain to the storage chamber (1) is installed from the top of the elevator (11) to the ceiling of the tank (T). After passing through the upper spiral (12), the grain circulating inside the dryer falls into a rotating diffuser (19) and is dispersed within the tank (T). The fuel tank (13) in Figure 2 is installed diagonally forward of the base (D).

[0025] A weight measuring device (27) is provided between the base (D) and the ground of the dryer shown in Figures 2 and 3, and automatically measures the weight of the grain loaded into the dryer. In addition, a dust extractor (14) is provided above the upper spiral (12) as a dust suction fan to remove dust generated from the grain during drying, and dust is removed by suction air.

[0026] As shown in Figures 1 to 3, the base (D) comprises a lower frame (20), an inclined plate (10), and an upper frame (21). The upper frame (21) and the lower frame (20) form a frame shape in the front, back, left, and right directions in a plan view. The front of the lower frame (20) and the front of the upper frame (21) are connected by a front support (22), the sides of the lower frame (20) and the upper frame (21) are connected by a middle support (23), and the rear of the lower frame (20) and the upper frame (21) are connected by a rear support (24). The upper part of the inclined plate (10) is connected to the side of the upper frame (21), and the lower part of the inclined plate (10) is connected to the front and rear of the lower frame (20). The outer surface of the lower part of the inclined plate (10) and the lower inside of the middle support (23) are connected by a reinforcing member (25) extending in the left-right direction. A space (26) is formed from the outside of the inclined plate (10) to the middle support (23).

[0027] The energy-saving drying mode in the present invention will be described.

[0028] In the dryer, various temperatures are detected by an outside air temperature sensor (31), a hot air temperature sensor (32), an exhaust air temperature sensor (33), and a grain temperature sensor (34) that detects the grain temperature.Moreover, a moisture meter (29) measures the moisture content at the time of loading, ventilation drying, hot air drying, and discharge.

[0029] As shown in Figure 4, when the outside air temperature is above a certain value (S1A) and the grain moisture content is also above a certain value (S1B), drying can be performed using ventilation alone (S1C). However, compared to hot air drying, which adds heat, the energy required to evaporate the moisture on the grain surface is small, so the drying rate per unit time is significantly slower. As a result, the drying time will be several times longer.

[0030] On the other hand, because the dryer is configured using the tempering drying method, the grain is continuously circulated within the dryer's tank (T) even during forced-air drying, and repeated transport by spiral or elevator increases the damage to the grain. If comparing only drying speed, the drying time may take nearly 3 to 10 times longer, and the amount of damage may increase proportionally. For this reason, forced-air drying adds air to the drying section continuously, but the grain circulation must be intermittent, reducing the amount of grain circulation.

[0031] When the energy-saving drying mode switch (40) in Figure 7 is selected, the energy-saving drying mode starts as shown in the flowchart in Figure 4. The outdoor air temperature sensor (31) measures the outdoor air temperature (S1A). Next, the grain moisture value is detected. If loading was performed immediately before, the moisture value at the time of loading is used for detection. If time has passed since the previous moisture value measurement or if data has not been registered, the dryer circulates the grain and begins measuring the moisture value. The energy-saving drying mode starts with ventilation operation, but the moisture value that serves as the judgment standard for this ventilation operation is registered in advance and is set as the reference moisture value. If the moisture value is above this reference moisture value (S1B), ventilation drying starts (S1C). If either the outdoor air temperature or the grain moisture value falls below the reference value, drying begins with hot air drying (S1D). Energy-saving drying mode using ventilation drying (S1C) is initiated, but because of the issue of grain damage mentioned above, if the grain temperature is above a specified value (S1E), it is possible to dry the grain sufficiently using intermittent circulation ventilation drying (S1F). This intermittent circulation can reduce grain damage. However, if the grain temperature is below a specified value (S1E), it is difficult to dry the grain efficiently using ventilation drying because there is insufficient energy to evaporate moisture from the grain even when air is passed through. Therefore, the efficiency of ventilation drying is improved by switching to continuous circulation ventilation drying (S1G) and drying outside the areas where the grain temperature is below the specified value.

[0032] The intermittent operation of the grain circulation system of the present invention will now be described.

[0033] When drying is performed in ventilation drying mode, the amount of heat required to evaporate the moisture is taken from the grain temperature. As ventilation drying progresses, the grain temperature gradually drops until it reaches the same temperature as the outside air temperature. Strictly speaking, the temperature equivalent to the latent heat of evaporation in the drying section is lower than the outside air temperature, but as a standard for the efficiency of ventilation operation, when the grain temperature reaches the same temperature as the outside air temperature, it can be determined that the grain remaining in the drying section and being ventilated has reached the limit of what can be dried using ventilation alone.

[0034] Therefore, when the grain temperature becomes the same as the outside air temperature (S1H), the system switches from intermittent circulation ventilation drying to continuous circulation ventilation drying (S1G).This allows the grain that has been ventilated and dried with sufficient air in the drying section to be replaced with grain that has remained in the tank (T) and has a higher grain temperature than the grain in the drying section, making it possible to ventilate and dry the grain.

[0035] Since the grain temperature, which is the temperature of the grain, is an approximate value to the exhaust air temperature, it is possible to use the exhaust air temperature as the standard for the detected grain temperature.

[0036] The reference temperature of the present invention will be described.

[0037] When energy-saving drying begins, the decision is made based on the outside air temperature (S1A). This allows the dryer to make an immediate decision even when it receives a start command from standby mode, as it constantly measures the temperature. However, when ventilation operation begins, the temperature control standard is based on the grain temperature being dried, not the temperature of the ventilating air (outside air temperature). Even with grain temperature sensors that directly measure grain temperature, accurate detection is difficult unless the air is passing through the dryer during ventilation. Therefore, as in the present invention, when energy-saving drying begins, the outside air temperature (S1A) is used as the standard to determine whether to operate ventilation or drying, and the grain temperature is detected after ventilation begins (S1H). This allows for accurate detection and determines whether to operate ventilation drying with continuous circulation (S1G) or ventilation drying with intermittent circulation (S1F). Without the control of the present invention, the dryer may enter hot air drying mode, detect basic data, and then switch to ventilation drying, resulting in an inefficient control that immediately extinguishes the flame after ignition, and can lead to problems such as users mistaking it for a sudden fire failure. Therefore, we believe that the control of the present invention is an effective drying method.

[0038] The present invention will now be described.

[0039] The energy-saving drying mode can be controlled depending on the type of grain. When intermittent circulation ventilation drying is started in energy-saving drying mode, poor flow can occur in the tank (T) due to intermittent circulation if the crop is wheat. To address this, the system controls the intervals between intermittent circulation ventilation drying depending on the type of grain, as shown in Figure 5.

[0040] Furthermore, the temperature setting when switching to hot air drying after completing the standard ventilation drying is also an important point for the energy-saving drying mode. In the present invention, if the user sets the drying setting (S6A) before starting the energy-saving drying mode, as shown in Figure 6, priority is given to control to start drying at this set temperature. However, if the user sets only the loading amount and does not set any other temperatures, the temperature is set by lowering the temperature by a predetermined amount (S6C) from the standard hot air temperature (S6B). Alternatively, if a system capable of automatically measuring the grain weight is provided, temperature setting based on the loading amount is performed automatically, so even when the energy-saving drying mode switch is pressed to start drying, the temperature is set by lowering the temperature by a predetermined amount from the standard hot air temperature.

[0041] The above-mentioned automatic measuring system for the loading amount will now be described.

[0042] The amount of loading is measured by the weighing scale (27) when the weight measurement switch on the operating device (35) is pressed. When the measurement is completed, the weight data is registered. This weight data will be used as the reference for the next measurement.

[0043] As shown in Figure 7, when the user presses the weight measurement switch, new weight data is measured. The new weight data is displayed and the difference from the previous data is calculated and displayed as the current loading weight, as shown in (36). The dryer's display system has a function that displays the difference between the current total weight and the previously measured weight as the current loading amount each time the weight measurement switch is pressed until drying begins, as shown in Figure 7. This means that when multiple containers are loaded, the weight of grain in each container can be confirmed by measuring the weight each time they are loaded. Yield management can be supported by registering this data on a terminal or operating device.

[0044] As shown in Figure 8, if the dryer has a 24-hour clock, it is possible to display the weight for each day and the difference in weight for each day. It is also possible to compare the same function over time.

[0045] As shown in Figure 9, when the control is set to perform so-called zero adjustment, a switch (37) for resetting the weight data is provided, and the weight added each time is displayed, and each individual weight up until the start of drying is registered. The registered individual weight data is compared with the total weight data at the start of drying, and the ratio of the individual weight data is calculated. This calculated ratio is then distributed to the total weight of the finished product, and displayed as shown in (38). Using this control, the device has the function of automatically stopping discharge according to the finished amount for each loading amount. [Explanation of symbols]

[0046] 16 Control section 18 Liquid crystal display 27 Weight measuring device 29 Moisture meter 31 Outside air temperature sensor 32 Hot air temperature sensor 33 Exhaust air temperature sensor 34 Grain temperature sensor 35 Weight measurement switch 37 Weight reset switch 40 Energy-saving drying mode switch

Claims

1. This grain dryer is equipped with sensors for detecting the outside air temperature, exhaust air temperature, and grain temperature, a moisture meter (29) for detecting the moisture content of the grain, a rotary valve (15) for feeding the grain to circulate it within the dryer, and a combustion burner (28) for performing hot air drying operation to dry the grain, and is capable of selecting between normal hot air drying operation and energy-saving drying operation, and when the energy-saving drying mode (40) is selected, if the outside air temperature is higher than a predetermined value, the grain moisture is higher than a predetermined value, and the grain temperature is higher than a predetermined value, the combustion burner is stopped and ventilation is continuously performed to flow air into the drying section, and the grain circulation is operated intermittently.

2. 2. The grain dryer according to claim 1, wherein the grain circulation is switched from the intermittent operation to continuous operation when the temperature of the exhaust air or the grain reaches the temperature of the outside air.

3. 3. The grain dryer according to claim 1, wherein when drying is started in the energy-saving drying mode, the intermittent time of grain circulation during ventilation drying is changed depending on the grain variety.

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