A method and device for drying grains with microwave
By detecting the humidity of the grain and calculating the pre-drying parameters, the pre-drying and adsorption process is carried out, the drying problem caused by uneven moisture is solved, a more uniform drying effect is achieved, and the quality of the grain is improved.
Patent Information
- Application Number
- CN202211327428.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-10-27
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2042-10-27
AI Technical Summary
In the existing microwave drying methods of grains, the drying is uneven due to uneven moisture content, resulting in a decrease in the quality of the grain after drying.
By detecting the grain humidity, calculating the microwave heater voltage and heating time in the pre-drying chamber, adjusting the air pressure and vapor volume, performing the pre-drying and adsorption process, reducing moisture differences, and adjusting the conveyor belt speed in the drying chamber to achieve uniform drying.
Improves the moisture uniformity of the grain, avoids the problem of excessive drying, and improves the quality of the grain after drying.
Smart Images
Figure CN116481263B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of microwave drying, and in particular to a method and device for microwave drying of grains. Background Art
[0002] Microwaves refer to electromagnetic waves with a wavelength range of 0.001 to 1m, a frequency range of 0.3 to 300GHz, and penetrating power. The magnetron of a microwave generator receives power from a power source to generate microwaves, which are transmitted to a microwave heater through a waveguide. The material to be heated is heated under the action of the microwave field. Microwave heating is different from general heating methods. The latter is conducted heating from the surface to the inside through thermal radiation from an external heat source; while microwave heating is body heating caused by dielectric loss in an electromagnetic field. This type of heating converts electromagnetic energy into thermal energy, and its energy is transmitted in the form of electromagnetic waves through space or a medium. The heating process of a substance is closely related to the polarization of the molecules inside the substance. The polarization of the medium to the microwave field is manifested as a loss of electric field current density. The dielectric constant of a general substance does not exceed 50, while the dielectric constant of water is 78.54. When a water-containing material is placed in the electromagnetic field generated by a microwave generator, the microwave field periodically changes the direction of the external electric field at a speed of hundreds of millions of times per second, causing the water molecules to swing rapidly and produce a significant thermal effect, thereby causing the temperature inside and on the surface of the material to rise rapidly at the same time.
[0003] Microwave drying is selective. Parts with high moisture content absorb more heat, lose moisture faster, and have higher temperature rise than other parts. As the temperature rises, the molecular movement becomes more active, which in turn enhances the material's ability to absorb microwaves. For a batch of grains, the moisture content between different grains may vary greatly. The uneven moisture content between grains is one of the main factors leading to uneven moisture content in grains after drying. For a single grain, there are differences in moisture content between the embryo and endosperm, and between the inner and outer layers of the grain, which will affect the drying characteristics of the grain. Summary of the invention
[0004] In view of the shortcomings of the existing grain microwave drying method and device mentioned in the background technology during use, the present invention provides a grain microwave drying method and device, which has the advantage of uniform drying and solves the problems mentioned in the background technology.
[0005] The present invention provides the following technical solution: a method for drying grains by microwave, comprising the following steps:
[0006] Step 1: Grain moisture detection: Use a moisture meter to detect the average moisture of the grains, select the equilibrium moisture of the grains close to the average moisture according to the grain type, and determine the temperature and relative humidity of the grains during decomposition and adsorption when the moisture content of the grains is equal to the equilibrium moisture;
[0007] Step 2, grain parsing: according to the parsing temperature of the grain when the moisture content of the grain determined in step 1 is equal to the equilibrium moisture content, the voltage and heating time of the microwave heater in the pre-drying chamber are calculated; according to the relative humidity in the pre-drying chamber when the moisture content of the grain determined in step 1 is equal to the equilibrium moisture content and the grain is in parsing, the air pressure and steam volume required to be input into the pre-drying chamber are calculated, and the grain is pre-dried in the pre-drying chamber;
[0008] Step 3, grain adsorption: according to the adsorption temperature of the grain when the water content of the grain determined in step 1 is equal to the equilibrium water content, the voltage and heating time of the microwave heater in the pre-drying chamber are calculated; according to the relative humidity in the pre-drying chamber when the water content of the grain determined in step 1 is equal to the equilibrium water content and the grain is in adsorption, the air pressure and steam volume required to be input into the pre-drying chamber are calculated, and the grain is pre-dried in the pre-drying chamber;
[0009] Step 4: Grain drying: Grains enter the drying chamber, and the moisture of the grains is first tested by a moisture meter. Then, the parameters of the microwave heater in the drying chamber and the speed of the conveyor belt are adjusted according to the moisture of the grains.
[0010] Preferably, in step 2 and step 3, the hot air required in the pre-drying chamber is transported from the drying chamber to the pre-drying chamber by using a dehumidification system.
[0011] Preferably, there is at least one drying chamber, and a separate conveyor belt is provided in each drying chamber.
[0012] A grain microwave drying device comprises a frame, on which a pre-drying chamber, a normal drying chamber and a microwave suppressor are installed, a conveyor belt is provided in each of the pre-drying chamber and the normal drying chamber, a cooling pipe is also provided in the pre-drying chamber below the conveyor belt, a feeder and a discharger are provided at both ends of the frame, the conveyor belt in the feeder extends into the pre-drying chamber, and the conveyor belt in the normal drying chamber near the discharger extends into the discharger, a microwave heater is provided in each of the pre-drying chamber and the normal drying chamber, the microwave heater is electrically connected to a controller, a thermometer, a moisture meter and a hygrometer are installed in the inner cavities of the pre-drying chamber and the normal drying chamber, and the thermometer, moisture meter and hygrometer are electrically connected to the controller.
[0013] Preferably, a dehumidification device is installed on the frame, and the air inlet end of the dehumidification device is connected with the inner cavity of the pre-drying chamber and the normal drying chamber through a branch pipe, and an electric control valve is installed on the branch pipe. The output end of the dehumidification device is connected with the atmosphere and the branch pipe installed on the pre-drying chamber, and the dehumidification device and the electric control valve are electrically connected to the controller.
[0014] Preferably, the conveyor belt comprises a belt body, a vertical hard plate is provided on the belt body, a bag is connected between two adjacent vertical hard plates, grains are placed above the bag, and the belt body, the vertical hard plate and the bag form a heat absorption chamber.
[0015] Preferably, a transmitter is installed on the side of the bag, and a receiver is installed on the inner wall of the frame. The receiver is used to receive the signal of the transmitter, and the transmitter and receiver are electrically connected to the controller.
[0016] Preferably, electrically controlled closed doors are provided between the adjacent pre-drying chamber and the normal drying chamber, and between the adjacent normal drying chambers, and the electrically controlled closed doors are electrically connected to the controller.
[0017] Preferably, the controller includes a collection unit, a storage unit, a comparison unit, a calculation unit and a driving unit, the input end of the collection unit is connected to the output ends of the thermometer, the moisture meter and the hygrometer, the input end of the comparison unit is connected to the output ends of the collection unit and the comparison unit, the output end of the comparison unit is connected to the input end of the calculation unit, the calculation unit includes a preheating parameter calculation module and a drying parameter calculation module, the output ends of the preheating parameter calculation module and the drying parameter calculation module are electrically connected to the driving unit, and the driving unit is connected to the microwave heater as well as the dehumidification device, the branch pipe and the conveyor belt.
[0018] The present invention has the following beneficial effects:
[0019] 1. The present invention uses the pre-drying analysis process to make the water in the parts of the grains with a water content greater than the selected equilibrium water content evaporate, thereby reducing the maximum water content value in the grains. In the pre-drying adsorption process, the parts of the grains with a water content lower than the selected equilibrium water content absorb water, thereby increasing the minimum water content value in the grains, thereby reducing the difference in water content in the grains, improving the uniformity of water content in the grains, avoiding the problem of excessive local drying of the grains due to uneven water content distribution in the normal drying process, and improving the quality of the dried grains.
[0020] 2. The present invention divides a whole batch of grains into small batches by utilizing a structure composed of a bag and a heat absorption chamber, and by laying grains on the bag, the temperature of the small batches of grains is monitored, and the contact area between the bag and the grains is increased, thereby improving the accuracy of grain temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a drying flow chart of the present invention;
[0022] Figure 2 It is a schematic structural diagram of the microwave drying device of the present invention;
[0023] Figure 3It is a structural schematic diagram of the conveyor belt of the present invention;
[0024] Figure 4 A top view of the conveyor belt of the present invention;
[0025] Figure 5 It is a block diagram of the composition of the controller of the present invention.
[0026] In the figure: 1. rack; 2. pre-drying chamber; 3. normal drying chamber; 4. microwave suppressor; 5. conveyor belt; 501. belt body; 502. vertical hard plate; 503. bag; 504. heat absorption chamber; 6. feeder; 7. discharger; 8. dehumidification device; 9. branch pipe; 10. electric control valve; 11. microwave heater; 12. thermometer; 13. moisture meter; 14. hygrometer; 15. controller; 1501. acquisition unit; 1502. storage unit; 1503. comparison unit; 1504. calculation unit; 1540. preheating parameter calculation module; 1541. drying parameter calculation module; 1505. drive unit; 16. transmitter; 17. receiver; 18. electric closed door. DETAILED DESCRIPTION
[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0028] See also Figure 1 , a method and device for drying grains by microwave, comprising the following steps:
[0029] Step 1: Grain moisture detection: Use a moisture meter to detect the average moisture of the grains, and determine the temperature and relative humidity of the grains during decomposition and adsorption when the moisture content of the grains is equal to the equilibrium moisture content;
[0030] Step 2, grain parsing: according to the parsing temperature of the grain when the moisture content of the grain determined in step 1 is equal to the equilibrium moisture content, the voltage and heating time of the microwave heater in the pre-drying chamber are calculated; according to the relative humidity in the pre-drying chamber when the moisture content of the grain determined in step 1 is equal to the equilibrium moisture content and the grain is in parsing, the air pressure and steam volume required to be input into the pre-drying chamber are calculated, and the grain is pre-dried in the pre-drying chamber;
[0031] Step 3, grain adsorption: according to the adsorption temperature of the grain when the water content of the grain determined in step 1 is equal to the equilibrium water content, the voltage and heating time of the microwave heater in the pre-drying chamber are calculated; according to the relative humidity in the pre-drying chamber when the water content of the grain determined in step 1 is equal to the equilibrium water content and the grain is in adsorption, the air pressure and steam volume required to be input into the pre-drying chamber are calculated, and the grain is pre-dried in the pre-drying chamber;
[0032] Step 4: Grain drying: Grains enter the drying chamber, and the moisture of the grains is first tested by a moisture meter. Then, the parameters of the microwave heater in the drying chamber and the speed of the conveyor belt are adjusted according to the moisture of the grains.
[0033] In step 2 and step 3, the hot air required in the pre-drying chamber is transported to the pre-drying chamber by the dehumidification system. When drying grains, when pre-drying the next batch of grains, the relative humidity of the air in the pre-drying chamber can be adjusted by reheating or cooling the hot air emitted during the normal drying of the previous batch of grains through the dehumidification system and transporting it to the pre-drying chamber, and the water vapor required in the pre-drying chamber can be transported to the pre-drying chamber by the dehumidification system, which emits the water vapor emitted during the drying of the previous batch of grains, thereby solving the energy problem.
[0034] There is at least one drying chamber, and a separate conveyor belt is provided in each drying chamber. Most of the microwave equipment for continuous drying in the prior art is formed by connecting a plurality of drying chambers, and a microwave generator needs to be provided in each drying chamber, while there is only one conveyor belt, so a large number of microwave generators are required. In the present application, a conveyor belt is provided in each drying chamber, and the time for which the grain stays in the drying chamber can be adjusted by adjusting the conveying speed of the conveyor belt, so the number of drying chambers can be reduced, and the cost can be reduced.
[0035] In the above steps, steps 1 to 3 are pre-drying processes, and step 4 is a normal drying process.
[0036] See attached Figure 2A grain microwave drying device comprises a frame 1, on which a pre-drying chamber 2 and a normal drying chamber 3 are installed. The pre-drying chamber 2 and the normal drying chamber 3 have the same structure. Conveyor belts 5 are arranged in the pre-drying chamber 2 and the normal drying chamber 3. A cooling pipe is also arranged in the pre-drying chamber 2 below the conveyor belt 5 for cooling the grains in the pre-drying chamber 2. A feeder 6 and a discharger 7 are respectively arranged at both ends of the frame 1. The conveyor belt 5 in the feeder 6 extends into the pre-drying chamber 2. The conveyor belt 5 in the normal drying chamber 3 near the discharger 7 extends into the discharger 7. A microwave heater 11 is arranged in the pre-drying chamber 2 and the normal drying chamber 3. The microwave heater 11 is electrically connected to a controller 15. A thermometer 12, a moisture meter 13 and a hygrometer 14 are installed in the inner cavities of the pre-drying chamber 2 and the normal drying chamber 3. The thermometer 12, the moisture meter 13 and the hygrometer 14 are electrically connected to the controller 15.
[0037] See attached Figure 3 The conveyor belt 5 includes a belt body 501, a vertical hard plate 502 is provided on the belt body 501, a bag 503 is connected between two adjacent vertical hard plates 502, grains are placed on the bag 503, the belt body 501, the vertical hard plate 502 and the bag 503 form a heat absorption chamber 504, and the heat absorption chamber 504 is filled with a thermosensitive gas, see the attached Figure 4, a transmitter 16 is installed on the side of the bag 503, and a receiver 17 is installed on the inner wall of the frame 1. The receiver 17 is used to receive the signal of the transmitter 16. The transmitter 16 and the receiver 17 are electrically connected to the controller 15. When the grain absorbs the microwaves emitted by the microwave heater 11, the temperature rises, and the heat of the grain is conducted to the heat absorption cavity 504 through the bag 503. The thermosensitive gas absorbs the heat and expands, so that the center point of the bag 503 moves upward, and the position of the transmitter 16 located at the center of the bag 503 rises accordingly, so the height of the signal received by the receiver 17 from the transmitter 16 increases. By collecting and converting the height value, the temperature of the grain can be activated. Compared with the temperature sensor used in the prior art, the contact area between the bag 503 and the grain in the present application is large, so the detection area is also large, and the detection accuracy is high. In the present application, a plurality of bags 503 and a heat absorption chamber 504 are arranged on the entire belt body 501, so a batch of grains on the conveyor belt 5 can be divided into a plurality of small batches, and the temperature of each small batch of grains can be detected. If the height difference of the transmitter 16 signal received by the multiple receivers 17 is small, it means that the temperature difference between each small batch of grains is small, and further means that the humidity difference of each small batch of grains is small. This is because microwave drying is selective, and the parts with high moisture content absorb more heat, lose water quickly, and the temperature rise is also higher than other parts. When the temperature rises, the molecular movement is more active, and the ability of the material to absorb microwaves is enhanced. Therefore, by counting the transmission height of each transmitter 16 signal, it can be known whether the moisture content of the batch of grains is uniform. If the moisture content is evenly distributed, the drying is also uniform and the drying is qualified. If the moisture content of the batch of grains is uneven, then under the same microwave power, the grains with less moisture content are over-dried, while the grains with more moisture content do not meet the drying requirements. For this batch of grains, the pre-drying and normal drying processes need to be repeated. In addition, when the gas in the heat absorption chamber 504 expands too much, the grains on the bag 503 flow to both sides, thereby mixing the grains. Since there are no grains on the current bag 503, the thermosensitive gas in the heat absorption chamber 504 can no longer absorb the heat of the grains, so the volume of the thermosensitive gas shrinks and sinks downward. At this time, the grains accumulated on both sides of the bag 503 roll down onto the sunken bag 503. In the process of the grains flowing to both sides and then flowing to the middle again, the mixing of the grains is promoted, further improving the accuracy of grain temperature detection.
[0038] A dehumidification device 8 is installed on the frame 1. The air inlet end of the dehumidification device 8 is connected to the inner cavity of the pre-drying chamber 2 and the normal drying chamber 3 through the branch pipe 9. The branch pipe 9 is installed with an electric control valve 10. The output end of the dehumidification device 8 is connected to the atmosphere and the branch pipe 9 installed on the pre-drying chamber 2. The dehumidification device 8 and the branch pipe 9 are both electrically connected to the controller 15. That is to say, the dehumidification device 8 can not only discharge the wet air in the pre-drying chamber 2 and the normal drying chamber 3, but also transport the air with adjusted humidity and temperature into the pre-drying chamber 2, so as to adjust and maintain the steam pressure of the air in the pre-drying chamber 2. After a period of drying, when the steam pressure on the surface of the grain is equal to the steam pressure of the air in the pre-drying chamber 2, the moisture in the grain will reach the corresponding equilibrium moisture.
[0039] An electrically controlled closed door 18 is provided between the adjacent pre-drying chamber 2 and the normal drying chamber 3, and between the normal drying chamber 3 and the normal drying chamber 3, and the electrically controlled closed door 18 is electrically connected to the controller 15. The electrically controlled closed door 18 is used to separate the pre-drying chamber 2 and the normal drying chamber 3 and keep them sealed, so as to adjust the air humidity and temperature in the pre-drying chamber 2 and the normal drying chamber 3.
[0040] See attached Figure 5 The controller 15 includes a collection unit 1501, a storage unit 1502, a comparison unit 1503, a calculation unit 1504 and a drive unit 1505. The input end of the collection unit 1501 is connected to the output end of the thermometer 12, the moisture meter 13 and the hygrometer 14. The storage unit 1502 stores a numerical table of equilibrium moisture relationships of different types of grains under various temperatures and relative air humidities. The data in the table are obtained by performing an equilibrium moisture test by setting different grain temperatures and air humidities as variables and equilibrium moisture as the result. The test method is already quite popular in the prior art. The input end of the comparison unit 1503 is connected to the output end of the acquisition unit 1501 and the comparison unit 1503, the output end of the comparison unit 1503 is connected to the input end of the calculation unit 1504, the calculation unit 1504 includes a preheating parameter calculation module 1540 and a drying parameter calculation module 1541, the output end of the preheating parameter calculation module 1540 and the drying parameter calculation module 1541 is electrically connected to the driving unit 1505, and the driving unit 1505 is connected to the microwave heater 11 and the dehumidification device 8, the branch pipe 9, and the conveyor belt 5.
[0041] The method of use of the present invention is as follows:
[0042] The grains in the feeder 6 are laid on the conveyor belt 5. Under the gravity of the grains, the bag 503 is sunken downward. At this time, the heat-sensitive gas in the heat absorption chamber 504 is in a state of being attached because it does not absorb heat. Figure 3The normal state shown; the grains enter the pre-drying chamber 2, and the moisture of the whole batch of grains is first detected by the moisture meter 13, and recorded as the average humidity; however, there may be a situation where the humidity of some grains is high and the humidity of some grains is low, and the humidity is uneven; and for a grain of grain, there may also be uneven humidity, so pre-drying is performed;
[0043] The thermometer 12 detects the temperature of the air in the pre-drying chamber 2, and the hygrometer 14 detects the humidity of the air in the pre-drying chamber 2. At the same time, the average value of the height of the transmitter 16 received by the receiver 17 is used as the temperature of the whole batch of grains. Then, according to the grain temperature, grain type and relative humidity of the air in the pre-drying chamber 2 obtained by the equilibrium moisture test, the equilibrium moisture value of the analysis and adsorption closest to the above three parameters is selected, and then the corresponding fixed grain temperature value and the fixed relative humidity of the air in the pre-drying chamber 2 in the table are determined. The grains are heated by the microwave heater 11 so that the temperature of the grains reaches the corresponding fixed grain temperature value and maintains the value. The air is transported into the pre-drying chamber 2 by the dehumidification device 8 so that the value in the pre-drying chamber 2 maintains the fixed relative humidity of the air. When the moisture meter 13 detects that the humidity of the grains has reached the equilibrium moisture, the drying of the grains is stopped.
[0044] According to the current temperature value of the grain and the current moisture content of the grain, find the relative humidity value of the air in the equilibrium moisture relationship value table obtained in the experiment under the conditions of being lower than the current temperature value of the grain and higher than the current moisture content of the grain. The temperature of the grain can be cooled naturally, or the grain can be cooled by installing a cooling pipe located under the conveyor belt 5 in the frame 1 so that the temperature of the grain reaches the value in the table. The relative humidity of the air in the pre-drying chamber 2 is maintained by the dehumidification device 8, and the temperature of the grain is maintained. When the moisture meter 13 detects that the moisture content of the grain is the corresponding equilibrium moisture in the table, the adsorption process is stopped.
[0045] During the pre-drying process, the uniformity of the moisture content distribution in the grains is balanced by analyzing and adsorbing the moisture in the grains. Specifically, during the grain analysis process, the part of the grain with a moisture content greater than the selected equilibrium moisture content is dried, and the moisture content is reduced. However, since the difference between the current equilibrium moisture content and the actual moisture content of the grain is small, the part with a moisture content less than the equilibrium moisture content will not be over-dried; and during the grain adsorption process, the part of the grain that originally had less moisture will absorb moisture, while the part with more moisture will not absorb moisture if it is higher than the equilibrium moisture content, but will absorb moisture if it is lower than the equilibrium moisture content, and since the equilibrium moisture content is closest to the true moisture value of the grain, the moisture absorbed by the grain is relatively small. Through the two processes of analysis and adsorption, the uniformity of the moisture content distribution in the grain is improved, and during the normal drying process, the grain will not have the problem of local over-drying, thereby improving the uniformity of grain drying and improving the quality of grain drying.
[0046] In addition, the reason why it is necessary to first conduct moisture balance tests on different types of grains at different temperatures and different air humidities to obtain a balance moisture relationship value table, and then set specific values according to the data in the balance moisture relationship value table in subsequent practical applications is because when conducting a balance moisture test, the test parameters are fixed, generally integers with the same interval, and in actual applications, the actual temperature of the grain or the air humidity is not equal to the parameters during the test. Therefore, setting the temperature of the grain and the air humidity to the parameter values during the test can ensure that when the adsorption and decomposition of the grain are in equilibrium, the actual moisture of the grain can reach the equilibrium moisture value.
[0047] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for drying grains by microwave, characterized in that: The following steps are involved: Step 1: Grain moisture detection: Use a moisture meter to detect the average moisture of the grains, select the equilibrium moisture of the grains close to the average moisture according to the grain type, and determine the temperature and relative humidity of the grains during decomposition and adsorption when the moisture content of the grains is equal to the equilibrium moisture; Step 2, grain parsing: according to the parsing temperature of the grain when the moisture content of the grain determined in step 1 is equal to the equilibrium moisture content, the voltage and heating time of the microwave heater in the pre-drying chamber are calculated; according to the relative humidity in the pre-drying chamber when the moisture content of the grain determined in step 1 is equal to the equilibrium moisture content and the grain is in parsing, the air pressure and steam volume required to be input into the pre-drying chamber are calculated, and the grain is pre-dried in the pre-drying chamber; Step 3, grain adsorption: according to the adsorption temperature of the grain when the water content of the grain determined in step 1 is equal to the equilibrium water content, the voltage and heating time of the microwave heater in the pre-drying chamber are calculated; according to the relative humidity in the pre-drying chamber when the water content of the grain determined in step 1 is equal to the equilibrium water content and the grain is in adsorption, the air pressure and steam volume required to be input into the pre-drying chamber are calculated, and the grain is pre-dried in the pre-drying chamber; Step 4: Grain drying: Grains enter the drying chamber, and the moisture of the grains is first detected by a moisture meter. Then, the parameters of the microwave heater in the drying chamber and the speed of the conveyor belt are adjusted according to the moisture of the grains. The invention relates to a grain microwave drying device for implementing the grain microwave drying method. The grain microwave drying device comprises a frame (1). A pre-drying chamber (2) and a drying chamber (3) and a microwave suppressor (4) are installed on the frame (1). Conveyor belts (5) are arranged in the pre-drying chamber (2) and the drying chamber (3). A cooling pipe is also arranged in the pre-drying chamber (2) below the conveyor belt (5). A feeder (6) and a discharger (7) are respectively arranged at two ends of the frame (1). The conveyor belt (5) in the feeder (6) extends to In the pre-drying chamber (2), a conveyor belt (5) in the drying chamber (3) close to the discharger (7) extends into the discharger (7); microwave heaters (11) are provided in the pre-drying chamber (2) and the drying chamber (3); the microwave heaters (11) are electrically connected to a controller (15); the inner cavities of the pre-drying chamber (2) and the drying chamber (3) are both equipped with thermometers (12), moisture meters (13) and hygrometers (14); the thermometers (12), moisture meters (13) and hygrometers (14) are electrically connected to the controller (15); The frame (1) is provided with a dehumidification device (8); the air inlet end of the dehumidification device (8) is connected to the inner cavities of the pre-drying chamber (2) and the drying chamber (3) through a branch pipe (9); an electric control valve (10) is installed on each of the branch pipes (9); the output end of the dehumidification device (8) is connected to the atmosphere and the branch pipe (9) installed on the pre-drying chamber (2); the dehumidification device (8) and the electric control valve (10) are both electrically connected to a controller (15); The conveyor belt (5) comprises a belt body (501), a vertical hard plate (502) is arranged on the belt body (501), a bag (503) is connected between two adjacent vertical hard plates (502), grains are placed above the bag (503), and the belt body (501), the vertical hard plate (502) and the bag (503) form a heat absorption chamber (504).
2. A grain microwave drying method according to claim 1, characterized in that: In the step 2 and step 3, the hot air required in the pre-drying chamber is transported to the pre-drying chamber by using the dehumidification system.
3. A grain microwave drying method according to claim 1, characterized in that: There is at least one drying chamber, and a separate conveyor belt is arranged in each drying chamber.
4. The method for drying grains by microwave according to claim 1, characterized in that: A transmitter (16) is installed on the side of the bag (503), and a receiver (17) is installed on the inner wall of the frame (1). The receiver (17) is used to receive signals from the transmitter (16). The transmitter (16), the receiver (17) and the controller (15) are electrically connected.
5. A grain microwave drying method according to claim 4, characterized in that: An electrically controlled closed door (18) is provided between the adjacent pre-drying chamber (2) and drying chamber (3), and between the drying chambers (3) and the drying chambers (3), and the electrically controlled closed door (18) is electrically connected to the controller (15).
6. A grain microwave drying method according to claim 5, characterized in that: The controller (15) comprises a collection unit (1501), a storage unit (1502), a comparison unit (1503), a calculation unit (1504) and a drive unit (1505); an input end of the collection unit (1501) is connected to the output ends of the temperature meter (12), the moisture meter (13) and the hygrometer (14); an input end of the comparison unit (1503) is connected to the output ends of the collection unit (1501) and the storage unit (1502); 03) is connected to the input end of a calculation unit (1504), the calculation unit (1504) comprising a preheating parameter calculation module (1540) and a drying parameter calculation module (1541), the output ends of the preheating parameter calculation module (1540) and the drying parameter calculation module (1541) are electrically connected to a driving unit (1505), and the driving unit (1505) is connected to a microwave heater (11) and a dehumidification device (8), a branch pipe (9), and a conveyor belt (5).