Drying system and method combining air source heat pump and electromagnetic heating

Abstract

The invention relates to the technical field of drying equipment and discloses an air source heat pump and electromagnetic heating combined drying system and method.The air source heat pump and electromagnetic heating combined drying system comprises a box body, the interior of the box body is divided into an equipment bin and a drying bin, an air flue switching device is fixedly installed in the equipment bin, and the input end of the air flue switching device communicates with the drying bin; an air channel switching device is arranged at the output end of the drying bin, an air source heat pump device is arranged at the output end of the air channel switching device, recycled hot air in the drying bin is distributed into the air source heat pump device through the air channel switching device, the air source heat pump device conducts primary heating on the air, an electromagnetic heating device is arranged at the output end of the air source heat pump device, and the electromagnetic heating device conducts secondary heating on the air. The output end of the electromagnetic heating device extends into the drying bin, and a drying assembly is arranged in the drying bin. According to the system, repeated dehumidification of dried air is avoided, unnecessary energy waste is fundamentally eliminated, and the overall energy efficiency of the system is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of drying equipment technology, and in particular to a drying system and method that combines an air source heat pump and electromagnetic heating. Background Technology

[0002] Air source heat pump drying technology, as a highly efficient and energy-saving method for agricultural product processing, has been widely applied in agricultural production, food processing, and industrial drying in recent years. This technology is primarily based on the reverse Carnot cycle principle, using a compressor to consume a small amount of electricity to convert low-grade heat energy from the environment into high-grade heat energy for material dehydration and drying. Compared to traditional electric heating or coal-fired drying methods, heat pump drying technology can save 40%-60% of energy consumption and does not contaminate the materials during the entire drying process, preserving their original quality and nutritional components.

[0003] As the agricultural product processing industry continues to demand higher drying quality, the limitations of single heat pump technology are becoming increasingly apparent. Especially in cold seasons or high-humidity environments, the heating efficiency and dehumidification capacity of air-source heat pumps decrease significantly, leading to longer drying times and increased energy consumption. To address this challenge, the industry has begun exploring composite drying solutions that combine air-source heat pumps with other heating technologies, aiming to achieve a dual improvement in energy efficiency and drying quality.

[0004] Electromagnetic heating technology, as another efficient and clean heating method, works by using electromagnetic induction to directly generate heat in a metal heating element. It boasts advantages such as high heat conversion efficiency (up to 90% or more), fast response speed, and high power density. Especially in drying scenarios requiring rapid heating and high-precision temperature control, electromagnetic heating technology demonstrates unique value.

[0005] A search of Chinese Patent Publication No. CN210154130U reveals a patent titled "An Electromagnetic Heating Defrosting Air Source Heat Pump." This patent relates to an electromagnetic heating defrosting air source heat pump, aiming to solve the problems of low heating performance and heat exchange efficiency in traditional heat pumps during defrosting. Its technical solution mainly includes a compressed circulation pipeline and an electromagnetic heating structure, wherein the electromagnetic heating structure is in contact with the finned evaporator. When defrosting is required, the electromagnetic heating structure is activated, while the heat pump system remains in heating mode. In this way, electromagnetic heating directly acts on the evaporator for defrosting, eliminating the need for an intermediate medium and improving heat exchange efficiency. Simultaneously, the refrigerant in the circulation pipeline can absorb heat from the air and some of the heat provided by the electromagnetic heating, making more efficient heat utilization and minimizing the impact on heating capacity during defrosting.

[0006] A search of Chinese Patent Publication No. CN205403146U reveals a patent titled "Integrated Air Source Heat Pump and High-Frequency Electromagnetic Heating Unit." This patent discloses an integrated air source heat pump and high-frequency electromagnetic heating unit, primarily aimed at solving the problems of low energy efficiency ratios or even inoperability of air source heat pumps in cold winters, and the inability of a single unit to simultaneously meet the needs of heating, cooling, hot water, and indoor heating in winter. This integrated unit connects the air source heat pump module and the high-frequency electromagnetic heating module in parallel to the input of a circulating hot water storage tank module, and achieves automatic control through a microcomputer integrated control module. These two modules can operate individually or simultaneously depending on different operating conditions. For example, the air source heat pump module is activated first when the temperature is suitable, while the high-frequency electromagnetic heating module can participate when rapid heating is needed or the water temperature is low, thereby meeting the hot water and heating needs under various operating conditions and achieving high efficiency and energy saving.

[0007] While the aforementioned existing technologies have addressed some of the issues related to air source heat pump operation during defrosting or in low-temperature environments, they still have some shortcomings: The electromagnetic defrosting solution provided by CN210154130U, although the heat pump system maintains heating during defrosting, primarily serves the defrosting process itself, limiting its impact on overall system energy allocation and efficiency improvement during defrosting; CN205403146U combines an air source heat pump with electromagnetic heating in parallel, improving applicability, but this parallel structure may result in insufficient optimization of the system's overall energy utilization, failing to fully utilize the rapid response characteristics of electromagnetic heating for deeper synergy with the heat pump system. For example, in applications requiring precise temperature and humidity control, such as drying, its energy efficiency and control precision may be insufficient.

[0008] Therefore, we propose a drying system and method that combines an air source heat pump and electromagnetic heating. Summary of the Invention

[0009] The present invention mainly addresses the technical problems existing in the prior art by providing a drying system and method that combines an air source heat pump and electromagnetic heating.

[0010] To achieve the above objectives, the present invention provides a drying system combining an air source heat pump and electromagnetic heating, comprising a housing, the inner part of which is divided into an equipment compartment and a drying compartment. An air duct switching device is fixedly installed in the equipment compartment. The input end of the air duct switching device is connected to the drying compartment, and an air source heat pump device is installed at the output end of the air duct switching device. Recovered hot air in the drying compartment is distributed to the air source heat pump device through the air duct switching device. The air source heat pump device performs primary heating of the air, with a maximum heating temperature of 80 degrees Celsius. An electromagnetic heating device is installed at the output end of the air source heat pump device, performing secondary heating of the air, with a heating temperature of 80-120 degrees Celsius. The output end of the electromagnetic heating device extends into the drying compartment, and a drying assembly is installed inside the drying compartment.

[0011] Preferably, the air duct switching device includes a first switch control valve, a second switch control valve, a first temperature and humidity sensor, and a control unit. The main pipe of the air duct switching device is connected to the drying chamber. The other end of the main pipe is divided into a first branch pipe and a second branch pipe. The first switch control valve is fixedly installed on the first branch pipe, and the second switch control valve is fixedly installed on the second branch pipe. The first temperature and humidity sensor is fixedly installed on the main pipe. The first temperature and humidity sensor monitors the temperature and humidity of the recovered hot air in real time and adjusts the opening and closing of the first switch control valve and the second switch control valve according to the system.

[0012] Preferably, the air source heat pump device includes a main evaporator, a heat insulation plate, an internal fan, a built-in condenser, a second temperature and humidity sensor, an expansion valve, a compressor, a water tank, an auxiliary heating evaporator, an external condenser, and a ventilation fan. The main evaporator, heat insulation plate, internal fan, and built-in condenser are sequentially fixed inside a sealed housing. The second branch pipe is connected to the sealed housing in the space between the main evaporator and the built-in condenser, and the first branch pipe is connected to the sealed housing in the space between the main evaporator and the built-in condenser.

[0013] Preferably, the second temperature and humidity sensor is fixedly installed in a sealed housing, and the expansion valve, compressor, water tank, auxiliary heating evaporator, external condenser and ventilation fan are connected in sequence.

[0014] The electromagnetic heating device includes a uniform air distribution plate, an electromagnetic heating winding, and a third temperature and humidity sensor. The uniform air distribution plate is fixedly installed on the inner wall of the uniform air distribution duct, and the electromagnetic heating winding is fixedly installed on the outer wall of the uniform air distribution duct. The electromagnetic heating winding has a segmented winding structure, and the third temperature and humidity sensor is fixedly installed at the tail end of the uniform air distribution duct.

[0015] Preferably, the drying assembly includes an exhaust pipe group and a movable drying rack. The exhaust pipe group is connected to the electromagnetic heating device. The exhaust pipe group consists of a set of vertical pipes and a dispersion pipe running from top to bottom along the vertical pipes. The dispersion pipes are connected to the vertical pipes. After bending and meandering, the dispersion pipes form a structure with a uniform exhaust plane. Each side wall of the dispersion pipe has a small hole with a diameter of 2-4 mm. The spacing between the small holes is arranged in an arithmetic progression decreasing along the length of the dispersion pipe. The movable drying rack is a support frame consisting of multiple sets of trays fixedly connected together. The trays and dispersion pipes are arranged alternately.

[0016] Preferably, the top of the drying chamber is also fixedly installed with an air blocking plate and an air return plate. The air return plate is connected to the main pipe of the air duct switching device. The air blocking plate is fixedly installed below the air return plate by a bracket. The air blocking plate covers the air blocking plate in the horizontal projection. Both the air blocking plate and the air return plate are funnel-shaped structures.

[0017] Preferably, the system also includes a control unit, which is electrically connected to the first temperature and humidity sensor, the second temperature and humidity sensor, and the third temperature and humidity sensor. The control unit is also electrically connected to the first switch control valve, the second switch control valve, the compressor, and the electromagnetic heating winding.

[0018] A drying method combining an air source heat pump and electromagnetic heating is also provided, applied to the aforementioned drying system combining an air source heat pump and electromagnetic heating, comprising the following steps:

[0019] Step 1: The hot air in the drying chamber is returned to the main duct of the air duct switching device via the return air plate. The first temperature and humidity sensor of the air duct switching device monitors the temperature and humidity of the returned hot air in real time.

[0020] Step 2: The control unit of the air duct switching device controls the opening and closing of the first switch control valve and the second switch control valve according to the monitoring results of the first temperature and humidity sensor: if the recovered hot air is humid, the first switch control valve is opened and the second switch control valve is closed, and the humid recovered hot air enters the main evaporator of the air source heat pump device for dehumidification; if the recovered hot air is dry, the first switch control valve is closed and the second switch control valve is opened, and the dry recovered hot air skips the main evaporator.

[0021] Step 3: The air source heat pump unit performs primary heating on the recovered hot air distributed in Step 2: The dried recovered hot air after dehumidification by the main evaporator, or the directly entering dried recovered hot air, is heated to a maximum of 80 degrees Celsius by a heat pump system consisting of an expansion valve, compressor, water tank, auxiliary heating evaporator, and external condenser, in conjunction with a built-in condenser and internal fan assembly. A second temperature and humidity sensor monitors the temperature and humidity of the air after primary heating.

[0022] Step 4: The electromagnetic heating device performs secondary heating on the air after the primary heating. It uses an air distribution duct with a uniform air distribution plate on the inner wall and a segmented electromagnetic heating winding on the outer wall. By independently adjusting the power of each segment of the electromagnetic heating winding, a temperature gradient that increases along the air supply direction is formed, heating the air to 80-120 degrees Celsius. The third temperature and humidity sensor monitors the temperature and humidity of the air after the secondary heating.

[0023] Step 5: The hot air after secondary heating is dispersed into the drying chamber through the air outlet pipe group of the drying component to dry the material on the movable drying rack tray; after heat exchange between the hot air and the material, it is returned to the air duct switching device through the return air plate to enter the next cycle; the control unit collects data from the first, second and third temperature and humidity sensors, dynamically controls the opening and closing of the first and second switch control valves, as well as the compressor frequency and the electromagnetic power of the electromagnetic heating winding, and adjusts the heating ratio of the air source heat pump and the electromagnetic heating.

[0024] Beneficial effects

[0025] This invention provides a drying system and method combining an air source heat pump and electromagnetic heating. It offers the following advantages:

[0026] (1) This drying system and method combining an air source heat pump and electromagnetic heating, by installing a temperature and humidity sensor in the main return air duct and configuring first and second switch control valves linked by the control unit, monitors the humidity status of the recovered air in real time. When the air is humid, it is guided to flow through the main evaporator for dehumidification before heating; when the air is dry, it is controlled to bypass the evaporator and directly enter the heating process. This avoids the repeated dehumidification of already dried air, fundamentally eliminates unnecessary energy waste, and significantly improves the overall energy efficiency of the system.

[0027] (2) This drying system and method combining an air source heat pump and electromagnetic heating employs an electromagnetic heating device composed of multiple sections of uniform airflow ducts. Each section of the duct has an independently wound electromagnetic heating winding on its outer wall, connected to an independent power control module. Through PWM or phase-shift power regulation, independent and precise control of the power of each winding is achieved, thereby forming a temperature gradient that increases along the airflow direction. This ensures a more uniform spatial distribution of the hot air entering the drying chamber and allows for flexible adaptation to the specific requirements of different drying materials for their heating curves, effectively improving drying quality and applicability.

[0028] (3) This drying system and method combining air source heat pump and electromagnetic heating integrates the air source heat pump device, electromagnetic heating device, air duct switching device and drying components into a single unit via the air duct and control unit, constructing a closed-loop system that integrates air dehumidification, gradient heating, uniform air supply and heat recovery. The central control unit realizes automatic perception, decision-making and execution of the entire process. It solves the problem of each component in traditional drying equipment being independent and lacking coordination, realizing a leap from "single equipment combination" to "integrated intelligent system", and ultimately achieving significant improvements in energy consumption, efficiency and drying quality. Attached Figure Description

[0029] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0030] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0031] Figure 1 This is a breakdown diagram of the overall structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0033] Figure 3 These are three views of the internal structure of the present invention;

[0034] Figure 4 This is a schematic diagram of the component structure arrangement of the present invention;

[0035] Figure 5 This is an exploded view of the component structure arrangement of the present invention;

[0036] Figure 6 This is a schematic diagram of the air outlet pipe assembly structure of the present invention;

[0037] Figure 7 This is a schematic diagram of the refrigerant air circulation of the present invention;

[0038] Figure 8 This is a schematic diagram illustrating the working principle of the system of the present invention.

[0039] Legend:

[0040] 01. Box body;

[0041] 02. Air source heat pump unit; 0201. Evaporator; 0202. Insulation plate; 0203. Fan; 0204. Condenser; 0205. Second temperature and humidity sensor; 0206. Expansion valve; 0207. Compressor; 0208. Water tank; 0209. Auxiliary heating evaporator; 0210. External condenser; 0211. Ventilation fan;

[0042] 03. Electromagnetic heating device; 0301. Air distribution plate; 0302. Electromagnetic heating winding; 0303. Third temperature and humidity sensor;

[0043] 04. Air duct switching device; 0401. First switch control valve; 0402. Second switch control valve; 0403. First temperature and humidity sensor; 0404. Control unit;

[0044] 05. Drying assembly; 0501. Air outlet pipe assembly; 0502. Movable drying rack; 0503. Air baffle plate; 0504. Air return plate. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example: A drying system combining an air source heat pump and electromagnetic heating, such as... Figures 1-7 As shown, the device includes a housing 01, which is divided into an equipment compartment and a drying compartment. The drying compartment stores the materials to be dried, while the equipment compartment provides installation support for the components. An air duct switching device 04 is fixedly installed inside the equipment compartment. The input end of the air duct switching device 04 is connected to the drying compartment, and the output end of the air duct switching device 04 is equipped with an air source heat pump device 02. The recovered hot air in the drying compartment is distributed to the air source heat pump device 02 through the air duct switching device 04. The air source heat pump device 02 performs primary heating of the air, with a maximum heating temperature of 80 degrees Celsius. An electromagnetic heating device 03 is installed at the output end of the air source heat pump device 02, which performs secondary heating of the air, with a heating temperature of 80-120 degrees Celsius. The output end of the electromagnetic heating device 03 extends into the drying compartment, inputting the hot air into the drying compartment for drying operations. A drying assembly 05 is installed inside the drying compartment to disperse and recover the hot air.

[0047] Specifically, the air duct switching device 04 includes a first switch control valve 0401, a second switch control valve 0402, a first temperature and humidity sensor 0403, and a control unit 0404. The main pipe of the air duct switching device 04 is connected to the drying chamber. The other end of the main pipe is divided into two branches. The first switch control valve 0401 is fixedly installed on the first branch, and the second switch control valve 0402 is fixedly installed on the second branch. The first temperature and humidity sensor 0403 is fixedly installed on the main pipe. The first temperature and humidity sensor 0403 monitors the temperature and humidity of the recovered hot air in real time and adjusts the opening and closing of the first switch control valve 0401 and the second switch control valve 0402 according to the system.

[0048] Specifically, the air source heat pump unit 02 includes a main evaporator 0201, a heat insulation plate 0202, an internal fan 0203, a built-in condenser 0204, a second temperature and humidity sensor 0205, an expansion valve 0206, a compressor 0207, a water tank 0208, an auxiliary heating evaporator 0209, an external condenser 0210, and an ventilation fan 0211. The main evaporator 0201, heat insulation plate 0202, internal fan 0203, and built-in condenser 0204 are sequentially fixed inside a sealed housing. A second branch pipe communicates with the sealed housing in the space between the main evaporator 0201 and the built-in condenser 0204. A first branch pipe is located between the main evaporator 0201 and the sealed housing, away from the built-in condenser 0204. In the space of 204, when the first temperature and humidity sensor 0403 detects humid recovered hot air, the first switch control valve 0401 opens and the second switch control valve 0402 closes. The humid recovered hot air becomes dry recovered hot air after evaporation by the main evaporator 0201. It is then heated by the built-in condenser 0204 before being output. When the first temperature and humidity sensor 0403 detects dry recovered hot air, the first switch control valve 0401 closes and the second switch control valve 0402 opens. The dry recovered hot air skips the evaporation of the main evaporator 0201 and is directly heated by the built-in condenser 0204 before being output, effectively avoiding the waste of energy caused by repeated dehumidification of the already dehumidified dry air.

[0049] The second temperature and humidity sensor 0205 is fixedly installed in the sealed housing to monitor the temperature and humidity of the hot air inside. The expansion valve 0206, compressor 0207, water tank 0208, auxiliary evaporator 0209, external condenser 0210, and ventilation fan 0211 are sequentially connected to form a heat pump, providing primary heating to the air inside the sealed housing. When the heat pump system is heating up, if the current heat acquisition is insufficient, the external condenser 0210 can absorb heat from the environment to heat the drying chamber. When large-scale dehumidification is required, the auxiliary evaporator 0209 can discharge excess heat from the heat pump system into the environment.

[0050] Specifically, a uniform air distribution plate 0301 is fixedly installed on the inner wall of the uniform air distribution duct, and an electromagnetic heating winding 0302 is fixedly installed on the outer wall of the uniform air distribution duct. The electromagnetic heating winding 0302 has a segmented winding structure, and the power of each segment can be independently adjusted by PWM or phase shift power regulation. Each segment is independently connected to the power control module to form a temperature gradient that increases along the air supply direction, thereby adjusting the heating temperature to meet the temperature requirements of different drying objects. A third temperature and humidity sensor 0303 is fixedly installed at the tail of each set of uniform air distribution ducts for monitoring the temperature and humidity of the air after electromagnetic heating.

[0051] Specifically, the drying assembly 05 includes an exhaust pipe assembly 0501 and a movable drying rack 0502. The exhaust pipe assembly 0501 is connected to the electromagnetic heating device 03. The exhaust pipe assembly 0501 consists of a set of vertical pipes and a dispersion pipe running from top to bottom along the vertical pipes. The dispersion pipes are connected to the vertical pipes. In this embodiment, the dispersion pipe is a U-shaped pipe. In other embodiments, it can be an S-shaped structure or any other structure that can form a uniform exhaust plane after bending and meandering. Each side wall of the dispersion pipe is provided with a small hole with a diameter of 2-4 mm. The hole spacing is arranged in an arithmetic decreasing manner along the length of the dispersion pipe to ensure that the difference in air volume between the far end and the near end is less than 10%, which facilitates the airflow.

[0052] The movable drying rack 0502 is a support frame consisting of multiple sets of trays fixedly connected together. The trays and the dispersing tubes are staggered in height. After the material is placed on the tray, it is dried by hot air, which also facilitates the overall movement of the material.

[0053] The top of the drying chamber is also fixedly equipped with an air baffle plate 0503 and an air return plate 0504. The air return plate 0504 is connected to the main pipe of the air duct switching device 04. Hot air is returned to the air duct switching device 04 through the air return plate 0504. The air baffle plate 0503 is fixedly installed below the air return plate 0504 by a bracket. The air baffle plate 0503 covers the air return plate 0504 in the horizontal projection. In this embodiment, both the air baffle plate 0503 and the air return plate 0504 are funnel-shaped structures, which first block the hot air, form a backflow, and then enter the air return plate 0504, thus prolonging the residence time of the hot and humid air.

[0054] Furthermore, it also includes a control unit 0404, which is electrically connected to the first temperature and humidity sensor 0403, the second temperature and humidity sensor 0205, and the third temperature and humidity sensor 0303 to collect air temperature and humidity data from these three locations. The control unit 0404 is also electrically connected to the first switch control valve 0401, the second switch control valve 0402, the compressor 0207, and the electromagnetic heating winding 0302. After processing the air temperature and humidity data, the control unit 0404 controls the air duct switching and heating power, dynamically calculates the heating ratio of the heat pump and the electromagnetic system, and achieves precise control through the frequency of the compressor 0207 and the electromagnetic power of the electromagnetic heating winding 0302.

[0055] A drying method combining an air source heat pump and electromagnetic heating is also provided, such as... Figure 8 As shown, it includes the following steps:

[0056] Step 1: The hot air in the drying chamber is returned to the main duct of the air duct switching device via the return air plate. The first temperature and humidity sensor of the air duct switching device monitors the temperature and humidity of the returned hot air in real time.

[0057] Step 2: The control unit of the air duct switching device controls the opening and closing of the first switch control valve and the second switch control valve according to the monitoring results of the first temperature and humidity sensor: if the recovered hot air is in a humid state, the first switch control valve is opened and the second switch control valve is closed, and the humid recovered hot air enters the main evaporator of the air source heat pump device for dehumidification; if the recovered hot air is in a dry state, the first switch control valve is closed and the second switch control valve is opened, and the dry recovered hot air skips the main evaporator.

[0058] Step 3: The air source heat pump unit performs primary heating on the recovered hot air distributed in Step 2: the dried recovered hot air after being dehumidified by the main evaporator, or the directly entering dried recovered hot air, is heated to a maximum of 80 degrees Celsius through the heat pump system, in conjunction with the built-in condenser and internal fan assembly. The second temperature and humidity sensor monitors the temperature and humidity of the air after the primary heating.

[0059] Step 4: The electromagnetic heating device performs secondary heating on the air after the primary heating. It uses an air distribution duct with a uniform air distribution plate on the inner wall and a segmented electromagnetic heating winding on the outer wall. By independently adjusting the power of each segment of the electromagnetic heating winding, a temperature gradient that increases along the air supply direction is formed, heating the air to 80-120 degrees Celsius. A third temperature and humidity sensor monitors the temperature and humidity of the air after the secondary heating.

[0060] Step 5: The hot air after secondary heating is dispersed into the drying chamber through the air outlet pipe group of the drying component to dry the material on the movable drying rack tray; after heat exchange between the hot air and the material, it is returned to the air duct switching device through the return air plate to enter the next cycle; the control unit collects data from the first, second and third temperature and humidity sensors, dynamically controls the opening and closing of the first and second switch control valves, as well as the compressor frequency and the electromagnetic power of the electromagnetic heating winding, and adjusts the heating ratio of the air source heat pump and the electromagnetic heating.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An air source heat pump and electromagnetic heating combined drying system, comprising a box body (01), characterized in that: The box (01) is internally divided into equipment bin and drying bin, the equipment bin is fixedly installed with air duct switching device (04), the input end of the air duct switching device (04) is communicated with the drying bin, the output end of the air duct switching device (04) is provided with air source heat pump device (02), the recycled hot air in the drying bin is distributed to the air source heat pump device (02) through the air duct switching device (04), the air source heat pump device (02) carries out primary heating to the air, and the maximum heating temperature is 80 degrees Celsius, the output end of the air source heat pump device (02) is provided with electromagnetic heating device (03), the electromagnetic heating device (03) carries out secondary heating to the air, and the heating temperature is 80-120 degrees Celsius, the output end of the electromagnetic heating device (03) extends into the drying bin, and the drying bin is internally provided with drying assembly (05).

2. The air source heat pump and electromagnetic heating combined drying system according to claim 1, characterized in that: The air duct switching device (04) includes first switch control valve (0401), second switch control valve (0402), first temperature and humidity sensor (0403) and control unit (0404), the main pipeline of the air duct switching device (04) is communicated with the drying bin, the other end of the main pipeline is divided into first branch pipeline and second branch pipeline, the first switch control valve (0401) is fixedly installed on the first branch pipeline, the second switch control valve (0402) is fixedly installed on the second branch pipeline, the first temperature and humidity sensor (0403) is fixedly installed on the main pipeline, the first temperature and humidity sensor (0403) carries out real-time monitoring on the temperature and humidity of the recycled hot air, and the opening and closing of the first switch control valve (0401) and the second switch control valve (0402) are adjusted according to the system.

3. The air source heat pump and electromagnetic heating combined drying system according to claim 2, characterized in that: The air source heat pump device (02) includes main evaporator (0201), heat insulation plate (0202), inner fan (0203), built-in condenser (0204), second temperature and humidity sensor (0205), expansion valve (0206), compressor (0207), water tank (0208), auxiliary evaporator (0209), external condenser (0210) and air exchange fan (0211), the main evaporator (0201), heat insulation plate (0202), inner fan (0203) and built-in condenser (0204) are sequentially fixed in a sealed shell, the second branch pipeline is communicated with the space between the main evaporator (0201) and the built-in condenser (0204) of the sealed shell, and the first branch pipeline is communicated with the space away from the built-in condenser (0204) of the main evaporator (0201) of the sealed shell.

4. The air source heat pump and electromagnetic heating combined drying system according to claim 3, characterized in that: The second temperature and humidity sensor (0205) is fixedly installed in the sealed shell, and the expansion valve (0206), the compressor (0207), the water tank (0208), the auxiliary evaporator (0209), the external condenser (0210) and the air exchange fan (0211) are sequentially connected.

5. The combination air source heat pump and electromagnetic heating drying system of claim 1, wherein: The electromagnetic heating device (03) comprises a uniform air distribution plate (0301), an electromagnetic heating winding (0302) and a third temperature and humidity sensor (0303). The uniform air distribution plate (0301) is fixedly installed on the inner wall of the uniform air distribution pipe. The electromagnetic heating winding (0302) is fixedly installed on the outer wall of the uniform air distribution pipe. The electromagnetic heating winding (0302) is a segmented winding structure. The third temperature and humidity sensor (0303) is fixedly installed at the tail of the uniform air distribution pipe.

6. The combination air source heat pump and electromagnetic heating drying system of claim 1, wherein: The drying assembly (05) comprises an air outlet pipe group (0501) and a movable drying rack (0502). The air outlet pipe group (0501) is communicated with the electromagnetic heating device (03). The air outlet pipe group (0501) comprises a group of vertical pipes and dispersion pipes arranged from top to bottom along the vertical pipes. The dispersion pipes are communicated with the vertical pipes. The dispersion pipes are bent and meandered to form a uniform air outlet plane structure. Small holes with a diameter of 2-4 mm are formed in each side wall of the dispersion pipes. The spacing between the small holes is arranged in an arithmetic decreasing manner along the length direction of the dispersion pipes. The movable drying rack (0502) is a support composed of a plurality of fixedly connected trays. The trays are staggered with the dispersion pipes.

7. The combination air source heat pump and electromagnetic heating drying system of claim 1, wherein: The top of the drying bin is also fixedly installed with a gas blocking disc (0503) and a gas return disc (0504). The gas return disc (0504) is communicated with the main pipe of the air duct switching device (04). The gas blocking disc (0503) is fixedly installed below the gas return disc (0504) by a support. The gas blocking disc (0503) covers the gas blocking disc (0503) in the horizontal projection. The gas blocking disc (0503) and the gas return disc (0504) are both in the shape of a horn.

8. The combination air source heat pump and electromagnetic heating drying system of claim 1, wherein: A control unit (0404) is also included. The control unit (0404) is electrically connected with the first temperature and humidity sensor (0403), the second temperature and humidity sensor (0205) and the third temperature and humidity sensor (0303). The control unit (0404) is also electrically connected with the first switch control valve (0401), the second switch control valve (0402), the compressor (0207) and the electromagnetic heating winding (0302).

9. A drying method combining an air source heat pump and electromagnetic heating, characterized by, The method is applied to the air source heat pump and electromagnetic heating combined drying system of any one of claims 1-8. The method comprises the following steps: Step 1: The hot air in the drying bin is recovered to the main pipe of the air duct switching device (04) through the gas return disc (0504). The first temperature and humidity sensor (0403) of the air duct switching device (04) monitors the temperature and humidity of the recovered hot air in real time. Step 2: The control unit (0404) of the air duct switching device (04) controls the opening and closing of the first and second switch control valves (0401) and (0402) according to the monitoring results of the first temperature and humidity sensor (0403): if the recovered hot air is humid, the first switch control valve (0401) is opened and the second switch control valve (0402) is closed, and the humid recovered hot air enters the main evaporator (0201) of the air source heat pump device (02) for dehumidification; if the recovered hot air is dry, the first switch control valve (0401) is closed and the second switch control valve (0402) is opened, and the dry recovered hot air skips the main evaporator (0201); Step 3: The air source heat pump device (02) performs primary heating on the recovered hot air distributed in step 2: the dry recovered hot air after dehumidification by the main evaporator (0201), or the dry recovered hot air directly entering, is heated to 0-80 degrees Celsius by the expansion valve (0206), the compressor (0207), the water tank (0208), the auxiliary evaporator (0209), the external condenser (0210), in cooperation with the built-in condenser (0204) and the internal fan (0203), and the second temperature and humidity sensor (0205) monitors the temperature and humidity of the air after primary heating; Step 4: The electromagnetic heating device (03) performs secondary heating on the air after primary heating, using the air uniformization pipeline with uniform air plate (0301) on the inner wall and segmented electromagnetic heating winding (0302) on the outer wall, by independently adjusting the power of each segment of electromagnetic heating winding (0302), forming a temperature gradient increasing along the air supply direction, heating the air to 80-120 degrees Celsius, and the third temperature and humidity sensor (0303) monitors the temperature and humidity of the air after secondary heating; Step 5: The hot air after secondary heating passes through the air outlet pipe group (0501) of the drying assembly (05) and is dispersed into the drying bin to dry the materials on the trays of the movable drying rack (0502); after heat exchange between the hot air and the materials, the hot air is recovered to the air duct switching device (04) through the air return disc (0504) for the next cycle; the control unit (0404) collects data from the first, second, and third temperature and humidity sensors (0303), dynamically controls the opening and closing of the first and second switch control valves (0402), and adjusts the electromagnetic power of the electromagnetic heating winding (0302) and the frequency of the compressor (0207), to adjust the heating proportion of the air source heat pump and the electromagnetic heating.

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