Infrared heat pump drier and drying method

Abstract

The application discloses an infrared heat pump drying machine, which comprises a drying chamber, a weighing platform arranged in the drying chamber, a drying rack arranged above the weighing platform, a plurality of drying trays arranged on the drying rack and used for placing materials, an air supply port and an air exhaust port arranged on the drying chamber, a heat pump drying system, an infrared drying system and an infrared heat pump drying method.

Description

Technical Field

[0001] This invention relates to the field of drying technology for traditional Chinese medicinal materials. More specifically, this invention relates to an infrared heat pump dryer and a drying method. Background Technology

[0002] Licorice, a vital medicinal herb in traditional Chinese medicine, possesses various medicinal properties such as clearing heat and detoxifying, moistening the lungs and relieving cough. However, if licorice is not properly dried after harvesting, it is highly susceptible to mold and spoilage due to improper storage conditions. This not only severely affects the medicinal quality of licorice, seriously threatening human health and safety, but also leads to significant waste of medicinal materials and increases the cost of licorice cultivation. The lack of theoretical research and practical application in the drying process of raw materials results in insufficient production capacity for semi-finished products such as licorice slices. The initial drying and processing of licorice is a pressing issue that needs to be addressed, especially since the storage, processing, and transportation of dried products all place high demands on the quality of dried licorice. Therefore, exploring an efficient, environmentally friendly drying equipment and method that can guarantee the quality of licorice is of paramount importance.

[0003] Currently, the traditional method for drying licorice is natural sun-drying. After harvesting, the licorice is spread out on large drying grounds, which not only occupies a large area and wastes space, but also requires a long drying period. Rainy weather can lead to widespread mold and rot. Furthermore, licorice dried under natural conditions suffers significant loss of its active ingredients, and hygiene cannot be guaranteed, making it susceptible to contamination by insects and flies. New drying technologies mainly include infrared drying, heat pump drying, vacuum freeze-drying, and microwave vacuum drying, each demonstrating its own advantages. Infrared drying primarily uses infrared radiation to heat the licorice, causing its internal moisture to evaporate rapidly. Heat pump drying mainly uses a heat pump system to recover and reuse the heat generated during the drying process, thus saving energy. However, in practical applications, we have found that both methods have some limitations. While infrared drying heats up quickly, it may cause the surface temperature of the licorice to become too high, affecting the quality of the medicinal material. While heat pump drying is energy-efficient, its drying speed is relatively slow. How to overcome the shortcomings of a single drying method and combine the advantages of two drying methods for simultaneous drying, in order to meet the need for simultaneous drying of large quantities of licorice, and to lay the licorice on multiple drying trays for simultaneous drying, thus ensuring the quality and drying efficiency of the licorice, is the technical problem that this application aims to solve. Summary of the Invention

[0004] This invention provides an infrared heat pump dryer and drying method that can combine infrared drying with heat pump drying. It can utilize the rapid heating characteristics of infrared rays and recover heat through the heat pump system, achieving the dual goals of energy saving and high efficiency.

[0005] To achieve these objectives and other advantages according to the present invention, an infrared heat pump dryer is provided, comprising:

[0006] The drying chamber is equipped with a weighbridge inside, and a drying rack is installed above the weighbridge. The drying rack has multiple drying trays for placing materials. The drying chamber is equipped with an air inlet and an air outlet.

[0007] A heat pump drying system includes a heat pump drying chamber and an evaporator, compressor, and condenser installed in the heat pump drying chamber. Humid air in the drying chamber enters the heat pump drying chamber through the exhaust vent and return air duct. After being dried, dehydrated, and heated by the heat pump, the air is transported back to the drying chamber through the supply air duct and the supply air vent. Low-temperature, low-pressure refrigerant gas is compressed by the compressor into high-temperature, high-pressure refrigerant gas, enters the condenser to condense into refrigerant liquid, and then enters the evaporator to evaporate into refrigerant gas.

[0008] An infrared drying system includes a pair of infrared drying racks and a pair of carbon fiber infrared radiation plate assemblies. The pair of infrared drying racks are mounted on both sides of the drying rack and located outside the weighbridge. Each infrared drying rack is equipped with a carbon fiber infrared radiation plate assembly via a lifting structure. Each carbon fiber infrared radiation plate assembly includes multiple carbon fiber infrared radiation plates, which can rotate synchronously relative to the infrared drying rack. One carbon fiber infrared radiation plate is located below a drying tray, and any pair of carbon fiber infrared radiation plates forms a gap.

[0009] Preferably, an air supply chamber is provided outside the drying chamber, and the air box of the air supply chamber is connected to the air supply pipe;

[0010] The air outlet includes a first air outlet and a plurality of second air outlets. The first air outlet is located at the top of the drying chamber and directly above the drying rack 3. The plurality of second air outlets are located on one side wall of the drying chamber. The plurality of second air outlets are connected to the air supply pipe through the air box of the air supply chamber. The first air outlet and the second air outlet are respectively equipped with a first air supply fan and a second air supply fan.

[0011] The exhaust vents include a first exhaust vent and a second exhaust vent. The first exhaust vent and the second exhaust vent are located on the upper and lower parts of another side wall of the drying chamber and are not on the same side wall as the multiple second air supply vents. The first exhaust vent and the second exhaust vent are respectively equipped with an upper exhaust fan and a lower exhaust fan.

[0012] Preferably, the air box of the air supply chamber is connected to multiple second air outlets through multiple reduced-diameter air outlet sections, and a ceramic heating plate is provided inside the air box on the opposite side of the multiple reduced-diameter air outlet sections.

[0013] Preferably, the infrared drying rack includes an upper frame and a lower frame. The upper frame is a U-shaped frame, and the carbon fiber infrared radiation plate assembly is disposed between a pair of vertical sections of the upper frame. The lower part of the pair of vertical sections of the upper frame is also provided with a pair of elongated notches. The lower frame is an L-shaped frame, and the horizontal part of the lower frame is fixed to the ground by anchor bolts. The vertical part of the lower frame is located outside the upper frame. The inner side of the vertical part of the lower frame is provided with a vertical guide groove, and the outer side of the upper frame is provided with a guide block. The guide groove and the guide block cooperate. The lower frame is provided with a bearing seat, and a pair of horizontal rotating shafts are parallel to each other through the bearing seat. The two ends of the horizontal rotating shafts extend to a pair of elongated notches, and one of the horizontal rotating shafts rotates under the drive of a first motor.

[0014] The lifting structure includes two lifting components. One lifting component is located in an elongated notch. The lifting component includes a pair of racks and a pair of gears. The pair of racks are located on opposite sidewalls of the elongated notch, and the pair of gears are located at the same end of a pair of horizontal rotating shafts. The pair of gears mesh with each other and respectively mesh with the pair of racks.

[0015] Preferably, the upper frame is equipped with multiple horizontal rollers via multiple pairs of bearings, and a carbon fiber infrared radiation plate is mounted on one of the horizontal rollers. One of the horizontal rollers rotates under the drive of a second motor, and the multiple horizontal rollers are linked together through a linkage structure.

[0016] An infrared heat pump drying method, using the aforementioned infrared heat pump dryer, includes:

[0017] Step 1: Move the drying rack above the weighbridge, and move a pair of infrared drying racks to both sides of the drying rack and outside the weighbridge;

[0018] Step 2: Lay the material on each drying tray, attach at least one first temperature sensor to the surface of the material, embed at least one second temperature sensor inside the material, weigh it, and calculate the initial weight of the material.

[0019] Step 3: Adjust the height of the pair of carbon fiber infrared radiation plates so that they are close to the drying tray above. Start the infrared drying system to perform radiation heating until the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the first temperature difference threshold.

[0020] Step 4: Turn off the infrared drying system, adjust the height of the pair of carbon fiber infrared radiation plates so that they are in the middle of the upper and lower drying trays, start the second air supply fan of the heat pump drying system for conduction heating, start the upper exhaust fan and lower exhaust fan of the heat pump drying system until the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the second temperature difference threshold, and the second temperature difference threshold is lower than the first temperature difference threshold.

[0021] Step 5: Start the infrared drying system for radiant heating, and simultaneously start the first and second air supply fans of the heat pump drying system for conductive heating. Turn off the upper and lower exhaust fans of the heat pump drying system, weigh the material, and calculate the real-time weight of the material until the moisture content of the material is reduced to the target moisture content threshold.

[0022] Preferably, when the time t taken for the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor to be less than the second temperature difference threshold is greater than a preset time t0, step four further includes:

[0023] Adjust the angle of a pair of carbon fiber infrared radiation plates, so that one set of carbon fiber infrared radiation plates rotates upward by 40~60° and the other set of carbon fiber infrared radiation plates rotates downward by 40~60°. Switch to start the first air blower of the heat pump drying system for conduction heating. Continue to start the upper exhaust fan and lower exhaust fan of the heat pump drying system, weigh, and calculate the real-time weight of the material until the moisture content of the material is reduced to the first moisture content threshold.

[0024] Adjust the angle of a pair of carbon fiber infrared radiation plates, so that one set of carbon fiber infrared radiation plates rotates downward by 40~60° and the other set rotates upward by 40~60°. Continue to start the first air blower of the heat pump drying system for conduction heating. Continue to start the upper and lower exhaust fans of the heat pump drying system. Weigh and calculate the real-time weight of the material until the moisture content of the material decreases to the second moisture content threshold. The second moisture content threshold is higher than the target moisture content threshold and lower than the first moisture content threshold.

[0025] Adjust the angle of the pair of carbon fiber infrared radiation plates to return them to horizontal. Adjust the height of the pair of carbon fiber infrared radiation plates so that they are positioned between the upper and lower drying trays. Proceed to step five.

[0026] The present invention has at least the following beneficial effects:

[0027] First, the infrared heat pump dryer of this invention combines infrared drying with heat pump drying. It utilizes the rapid heating characteristics of infrared rays and recovers heat through a heat pump system, achieving both energy saving and high efficiency. The infrared heat pump drying method of this invention ensures the quality and drying efficiency of licorice, minimizes the loss of medicinal components, avoids the loss of heat-sensitive components, and effectively solves problems such as poor rehydration properties, significant nutrient loss, and unsatisfactory taste, color, and flavor. Simultaneously, it reduces the degree of oxidative denaturation of the components.

[0028] Secondly, the drying chamber of this invention is the main place for combined drying. The drying rack and materials are weighed by setting up a weighbridge in the drying chamber, and then the moisture content of the materials is calculated to measure the degree of dryness of the materials. The drying rack can be a general frame structure. The drying trays are detachable, preferably hung or erected. The drying trays have a mesh structure to facilitate simultaneous heat transfer from top to bottom and from bottom to top.

[0029] Third, the heat pump drying system of the present invention is used to heat the air entering the drying chamber. Specifically, the compressor compresses the low-temperature, low-pressure refrigerant gas into a high-temperature, high-pressure refrigerant gas. Then, this high-temperature, high-pressure refrigerant gas enters the condenser and, through a series of heat exchange processes, transfers the heat it carries to the external environment. It then gradually cools down and condenses into a refrigerant liquid, which enters the evaporator to evaporate into a refrigerant gas, thus achieving effective heat transfer. The evaporator absorbs the heat in the air and some of the residual heat discharged during the drying process, while the condenser preheats the air entering the drying chamber by releasing a large amount of heat.

[0030] Fourth, the infrared drying system of the present invention is used to heat the material on the drying tray. There is a pair of infrared drying racks, symmetrically arranged on both sides of the drying rack. They do not contact the drying rack and are not included in the weighing weight. The infrared drying rack is mainly used to install carbon fiber infrared radiation plate groups. After a pair of carbon fiber infrared radiation plate groups are assembled, each pair of carbon fiber infrared radiation plates is located below each layer of drying tray, realizing heat radiation to the drying tray from bottom to top. The height of the carbon fiber infrared radiation plate group relative to the infrared drying rack can be adjusted to adjust the distance between it and the upper drying tray. The lifting structure can be a hydraulic cylinder, hydraulic lifting frame or other power device. The carbon fiber infrared radiation plate group can also be rotated relative to the infrared drying rack to adjust the angle between it and the upper drying tray. A group of carbon fiber infrared radiation plates rotate synchronously, which can be achieved through belt transmission, gear meshing transmission or other power devices.

[0031] Fifth, this invention features an external air supply chamber for hot air diversion and guidance. A first air outlet and a first air supply fan deliver hot air from top to bottom, while a second air outlet and a second air supply fan deliver hot air horizontally. The first and second exhaust outlets achieve convective hot air drying, reducing energy consumption and minimizing nutrient loss. By incorporating multiple reduced-diameter exhaust pipe sections into the air box, the exhaust air velocity is increased. Furthermore, the installation of ceramic heating plates further enhances insulation and heating, enabling hot air circulation and shortening drying time.

[0032] Sixth, this invention designs the infrared drying frame as an upper frame and a lower frame, which are mutually cooperating moving and stationary frames. To improve the stable lifting and lowering of the upper and lower frames, in addition to the lifting structure, auxiliary support structures such as elastic elements and power components can be set between them. The upper frame has a long strip-shaped notch for connecting with the lower frame, i.e., the meshing of a rack and pinion, to achieve power transmission, so that the upper frame can lift and lower at a stable and uniform speed relative to the lower frame. Horizontal rollers are rotatably mounted on the upper frame via bearings. Rotating the horizontal rollers causes the carbon fiber infrared radiation plates to rotate. The horizontal rollers can be linked by installing gear assemblies. For example, two adjacent horizontal rollers can be equipped with roller gears of the same specification. The two roller gears mesh with the drive gear simultaneously, driving the drive gear to rotate one carbon fiber infrared radiation plate group. The horizontal rollers can also be linked by installing belt assemblies. For example, two adjacent horizontal rollers can be driven by a belt to drive one horizontal roller to rotate one carbon fiber infrared radiation plate group.

[0033] Seventh, the drying method of this invention can solve the problems of slow initial heating rate in heat pump drying and excessively high surface temperature and poor moisture dissipation in infrared drying. First, the infrared drying system is started for radiative heating. The penetrating power of infrared radiation causes water molecules within the material to move, leading to moisture evaporation and a rapid reduction in temperature difference. Then, the infrared drying system is shut off, and the heat pump drying system is started. A second exhaust fan is used for conductive heating, while the upper and lower exhaust fans are simultaneously activated to recover heat from the humid air, significantly reducing energy consumption. This also creates convective hot air drying, further reducing the temperature difference.

[0034] Eighth, when the thickness or bulk density of the material is large, the heat pump drying system is further activated. The first air blower is used for conductive heating, and the upper and lower exhaust fans are activated simultaneously. The angle of a pair of carbon fiber infrared radiation plates is adjusted, and then the angle of the pair of carbon fiber infrared radiation plates is adjusted again to form different tortuous paths. There is a humidity gradient between the material moisture content and the surrounding air. The concentration difference diffusion dynamics are used to achieve uniform drying of the material surface, which improves the efficiency of heat pump drying. Under the premise of reducing energy consumption, the rate of moisture content reduction is accelerated. Finally, the infrared drying system is activated, the heat pump drying system is activated, the upper and lower exhaust fans are turned off, the hot air blowing angle is increased, the internal hot air is disturbed, further dehumidification is achieved, and the drying effect is improved.

[0035] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0036] Figure 1This is a plan view of an infrared heat pump dryer according to one technical solution of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of an infrared heat pump dryer according to one technical solution of the present invention;

[0038] Figure 3 This is a schematic diagram of the structure of a drying rack according to one technical solution of the present invention;

[0039] Figure 4 This is a schematic diagram of the structure of an infrared drying system according to one technical solution of the present invention;

[0040] Figure 5 This is a schematic flowchart of an infrared drying method according to one technical solution of the present invention;

[0041] Figure 6 This is a photograph of a dried licorice sample according to an embodiment of the present invention. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0043] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0044] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0045] like Figures 1-4 As shown, the present invention provides an infrared heat pump dryer, comprising:

[0046] The drying chamber 1 is equipped with a weighbridge 2 inside, and a drying rack 3 is installed above the weighbridge 2. The drying rack 3 is equipped with multiple drying trays 4 for placing materials. The drying chamber 1 is equipped with an air inlet and an air outlet.

[0047] Drying chamber 1 is the main area for combined drying. A weighbridge 2 is installed in drying chamber 1 to weigh the drying racks 3 and the materials, thereby calculating the moisture content of the materials and measuring their degree of dryness. Specifically, the weight of the drying rack 3 is w0, the initial weight of the material placed on the drying rack 3 is w1, and the weight of the material on the drying rack 3 after drying for a period of time is w2. The moisture content U% = The drying rack 3 can be a general frame structure. The drying tray 4 can be installed in a detachable manner, preferably by hanging or assembling. The drying tray 4 has a mesh structure to facilitate simultaneous heat transfer from top to bottom and from bottom to top.

[0048] The heat pump drying system includes a heat pump drying outer casing 9 and an evaporator, compressor, and condenser installed in the heat pump drying outer casing 9. Humid air in the drying chamber 1 enters the heat pump drying outer casing 9 through the exhaust port and return air pipe. After being dried, dehydrated, and heated by the heat pump, the air is transported back to the drying chamber 1 through the supply air pipe and the supply air port. The low-temperature and low-pressure refrigerant gas is compressed by the compressor into a high-temperature and high-pressure refrigerant gas, enters the condenser to condense into refrigerant liquid, and then enters the evaporator to evaporate into refrigerant gas.

[0049] The heat pump drying system is used to heat the air entering the drying chamber 1. Specifically, the compressor compresses the low-temperature, low-pressure refrigerant gas into a high-temperature, high-pressure refrigerant gas. Then, this high-temperature, high-pressure refrigerant gas enters the condenser and, through a series of heat exchange processes, transfers the heat it carries to the external environment. It then gradually cools down and condenses into a refrigerant liquid, which enters the evaporator to evaporate into a refrigerant gas. This achieves effective heat transfer. The evaporator absorbs the heat from the air and some of the waste heat discharged during the drying process. The condenser preheats the air entering the drying chamber 1 by releasing a large amount of heat.

[0050] The infrared drying system includes a pair of infrared drying racks 10 and a pair of carbon fiber infrared radiation plate assemblies. The pair of infrared drying racks 10 are mounted on both sides of the drying rack 3 and located outside the weighbridge 2, i.e., no weight is applied to the weighbridge 2. Each infrared drying rack 10 is equipped with a carbon fiber infrared radiation plate assembly via a lifting structure. Each carbon fiber infrared radiation plate assembly includes multiple carbon fiber infrared radiation plates 11. The multiple carbon fiber infrared radiation plates 11 can rotate synchronously relative to the infrared drying rack 10. One carbon fiber infrared radiation plate 11 is located below a drying tray 4, and any pair of carbon fiber infrared radiation plates 11 forms a gap.

[0051] The infrared drying system is used to heat the material on the drying tray 4. There is a pair of infrared drying frames 10, which are symmetrically arranged on both sides of the drying rack 3. They do not contact the drying rack 3 and are not included in the weighing weight. The infrared drying frames 10 are mainly used to install carbon fiber infrared radiation plate groups. After the pair of carbon fiber infrared radiation plate groups are assembled, each pair of carbon fiber infrared radiation plates 11 is located below each layer of drying tray 4, realizing heat radiation to the drying tray 4 from bottom to top. The height of the carbon fiber infrared radiation plate group relative to the infrared drying rack 3 can be adjusted to adjust the distance between it and the upper drying tray 4. The lifting structure can be a hydraulic cylinder, hydraulic lifting frame or other power device. The carbon fiber infrared radiation plate group can also be rotated relative to the infrared drying rack 3 to adjust the angle between it and the upper drying tray 4. A group of carbon fiber infrared radiation plates 11 rotate synchronously, which can be driven by multiple motors one by one, or by belt transmission, gear meshing or other power devices.

[0052] In the above technical solution, the infrared heat pump dryer of the present invention combines infrared drying and heat pump drying, which can utilize the rapid heating characteristics of infrared rays and recover heat through the heat pump system, thus achieving the dual goals of energy saving and high efficiency.

[0053] In another technical solution, an air supply chamber 12 is provided outside the drying chamber 1, and the air box 13 of the air supply chamber 12 is connected to the air supply pipe;

[0054] The air outlet includes a first air outlet 5 and a plurality of second air outlets 6. The first air outlet 5 is located at the top of the drying chamber 1 and directly above the drying rack 3. The plurality of second air outlets 6 are located on one side wall of the drying chamber 1. The plurality of second air outlets 6 are connected to the air supply pipe through the air box 13 of the air supply chamber 12. The first air outlet 5 and the second air outlets 6 are respectively equipped with a first air supply fan and a second air supply fan.

[0055] The exhaust vents include a first exhaust vent 7 and a second exhaust vent 8. The first exhaust vent 7 and the second exhaust vent 8 are located on the upper and lower parts of another side wall of the drying chamber 1, and are not on the same side wall as the multiple second air supply vents 6. The first exhaust vent 7 and the second exhaust vent 8 are respectively equipped with an upper exhaust fan and a lower exhaust fan.

[0056] In the above technical solution, an air supply chamber 12 is set outside the drying chamber 1 to divert and guide the hot air. The first air supply port 5 and the first air supply fan realize the hot air supply from top to bottom, the second air supply port 6 and the second air supply fan realize the hot air supply in the horizontal direction, and the first exhaust port 7 and the second exhaust port 8 realize convection hot air drying, which reduces energy consumption and minimizes nutrient loss.

[0057] In another technical solution, the air box 13 of the air supply chamber 12 is connected to multiple second air outlets 6 one by one through multiple reduced-diameter air outlet sections. A ceramic heating plate 14 is provided inside the air box 13 on the opposite side of the multiple reduced-diameter air outlet sections. By setting multiple reduced-diameter air outlet sections in the air box 13, the air velocity is increased. The ceramic heating plate 14 further achieves heat preservation and heating, realizing hot air circulation and shortening the drying time.

[0058] In another technical solution, such as Figure 2-3 As shown (where Figure 3 To show the lifting structure, the vertical part of the lower frame 16 is omitted. The infrared drying rack 10 includes an upper frame 15 and a lower frame 16. The upper frame 15 is a U-shaped frame, i.e., a portal frame. The carbon fiber infrared radiation plate assembly is located between a pair of vertical parts of the upper frame 15. The lower part of the pair of vertical parts of the upper frame 15 also has a pair of elongated notches. The lower frame 16 is an L-shaped frame. The horizontal part of the lower frame 16 is fixed to the ground by anchor bolts and has a counterweight. The vertical part of the lower frame 16 is located at... A vertical guide groove is provided on the outer side of the upper frame 15 and the inner side of the vertical part of the lower frame 16. A guide block is provided on the outer side of the upper frame 15. The guide groove and the guide block cooperate to ensure the linear lifting and lowering movement of the upper frame 15 relative to the lower frame 16 under the traction of the lifting assembly. The lower frame 16 is provided with a bearing seat 17. There are one or more bearing seats 17. A pair of horizontal rotating shafts 18 are parallel to each other through the bearing seats 17. The two ends of the horizontal rotating shafts 18 extend to a pair of elongated notches. One of the horizontal rotating shafts 18 rotates under the drive of the first motor.

[0059] The lifting structure includes two lifting components. One lifting component is located in an elongated notch. The lifting component includes a pair of racks 19 and a pair of gears 20. The pair of racks 19 are located on opposite sidewalls of the elongated notch. The pair of gears 20 are located at the same end of a pair of horizontal rotating shafts 18. The pair of gears 20 mesh with each other and respectively mesh with the pair of racks 19.

[0060] In the above technical solution, the infrared drying frame 10 is designed as an upper frame 15 and a lower frame 16. The upper frame 15 and the lower frame 16 are a moving frame and a stationary frame that cooperate with each other. In order to improve the stable lifting and lowering of the upper frame 15 and the lower frame 16, in addition to the lifting structure, an auxiliary support structure, such as an elastic element or a power element, can be set between the upper frame 15 and the lower frame 16. The upper frame 15 is provided with a long strip-shaped notch for connecting with the lower frame 16, that is, the meshing of the rack 19 and the gear 20 to realize power transmission, so that the upper frame 15 can lift and lower at a stable and uniform speed relative to the lower frame 16.

[0061] In another technical solution, such as Figure 2-3As shown, the upper frame 15 is equipped with multiple horizontal rollers 21 via multiple pairs of bearings. Each horizontal roller 21 has a carbon fiber infrared radiation plate 11 mounted on it. One of the horizontal rollers 21 rotates under the drive of a second motor, and the multiple horizontal rollers 21 are linked together through a linkage structure. The horizontal rollers 21 are rotatably mounted to the upper frame 15 via bearings. Rotating the horizontal rollers 21 causes the carbon fiber infrared radiation plate 11 to rotate. The horizontal rollers 21 can be linked together by installing gear assemblies. For example, two adjacent horizontal rollers 21 can be equipped with roller gears of the same specification. The two roller gears mesh with the drive gear simultaneously, driving the drive gear to rotate one carbon fiber infrared radiation plate assembly. The horizontal rollers 21 can also be linked together by installing belt assemblies. For example, two adjacent horizontal rollers 21 can be driven by a belt to drive one horizontal roller 21 to rotate one carbon fiber infrared radiation plate assembly.

[0062] like Figure 5 As shown, the infrared heat pump drying method, using the aforementioned infrared heat pump dryer, includes:

[0063] Step 1: Move the drying rack 3 above the weighbridge 2. The weight of the drying rack 3 is w0. Move a pair of infrared drying racks 10 to both sides of the drying rack 3 and to the outside of the weighbridge 2.

[0064] Step 2: Lay the material on each drying tray 4, attach at least one first temperature sensor to the surface of the material, and embed at least one second temperature sensor inside the material. Weigh the material. The initial weight of the material after it is placed on the drying rack 3 is w1. Calculate the initial weight of the material w1-w0.

[0065] Step 3: As Figure 5 As shown in Figure a, adjust the height of a pair of carbon fiber infrared radiation plates so that they are close to the drying tray 4 above, start the infrared drying system to perform radiation heating until the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the first temperature difference threshold.

[0066] Step Four: As Figure 5 As shown in b, turn off the infrared drying system, adjust the height of a pair of carbon fiber infrared radiation plates so that they are located between the upper and lower drying trays 4, start the second air supply fan of the heat pump drying system for conduction heating, start the upper exhaust fan and lower exhaust fan of the heat pump drying system until the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the second temperature difference threshold, and the second temperature difference threshold is lower than the first temperature difference threshold.

[0067] Step 5: Start the infrared drying system for radiant heating, and simultaneously start the first and second air supply fans of the heat pump drying system for conductive heating. Turn off the upper and lower exhaust fans of the heat pump drying system. Weigh the material on drying rack 3 after a period of drying, which is w2. Calculate the real-time weight of the material, w2 - w0. Moisture content U% = This continues until the moisture content of the material decreases to the target threshold.

[0068] The above technical solution addresses the issues of slow initial heating rate in heat pump drying and excessively high surface temperature and poor moisture dissipation in infrared drying. First, the infrared drying system is activated for radiant heating. The penetrating power of infrared radiation causes water molecules within the material to move, leading to evaporation and a rapid reduction in temperature difference. Then, the infrared drying system is shut down, and the heat pump drying system is activated. A second exhaust fan is used for conductive heating, while the upper and lower exhaust fans are simultaneously activated to recover heat from the humid air, significantly reducing energy consumption. This also creates convective hot air drying, further reducing the temperature difference. Finally, the infrared drying system and the heat pump drying system are activated simultaneously, while the upper and lower exhaust fans are shut down. This increases the angle of the hot air blowing, causing internal air turbulence and further dehumidification, improving the drying effect.

[0069] In another technical solution, when the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the second temperature difference threshold and the time t taken is greater than the preset time t0, step four further includes:

[0070] like Figure 5 As shown in c, adjust the angle of a pair of carbon fiber infrared radiation plate groups so that one group of carbon fiber infrared radiation plates 11 rotates upward by 40~60° and the other group of carbon fiber infrared radiation plates 11 rotates downward by 40~60°. Switch to start the first air blower of the heat pump drying system for conduction heating. Continue to start the upper exhaust fan and lower exhaust fan of the heat pump drying system, weigh, and calculate the real-time weight of the material until the moisture content of the material is reduced to the first moisture content threshold.

[0071] like Figure 5 As shown in d, adjust the angle of a pair of carbon fiber infrared radiation plates, so that one set of carbon fiber infrared radiation plates 11 rotates downward by 40~60° and another set of carbon fiber infrared radiation plates 11 rotates upward by 40~60°. Continue to start the first air blower of the heat pump drying system for conduction heating, continue to start the upper exhaust fan and lower exhaust fan of the heat pump drying system, weigh, and calculate the real-time weight of the material until the moisture content of the material decreases to the second moisture content threshold. The second moisture content threshold is higher than the target moisture content threshold and the second moisture content threshold is lower than the first moisture content threshold.

[0072] like Figure 5As shown in b, adjust the angle of the pair of carbon fiber infrared radiation plates to return them to horizontal, and adjust the height of the pair of carbon fiber infrared radiation plates so that they are positioned between the upper and lower drying trays 4. Proceed to step five.

[0073] In the above technical solution, when t > t0, it indicates that the material drying speed is relatively slow and uneven. This may be due to the large thickness or high bulk density of the material. Therefore, the heat pump drying system is further activated, and the first air blower is used for conduction heating. At the same time, the upper and lower exhaust fans are activated, and the angle of a pair of carbon fiber infrared radiation plates is adjusted. The angle of the pair of carbon fiber infrared radiation plates is adjusted again to form different tortuous paths. There is a humidity gradient between the material moisture content and the surrounding air. The uniform drying of the material surface is achieved by using the concentration diffusion dynamics, which improves the efficiency of heat pump drying and promotes the reduction rate of moisture content while reducing energy consumption.

[0074] In one application example, the drying method of this invention combines infrared drying and heat pump drying alternately, resulting in a dried licorice sample as shown below. Figure 6 As shown. Phenolic and ketone compounds are important nutrients in licorice, but they are easily oxidized or degraded during the drying process, thus reducing the nutritional quality of licorice. The effects of the drying method of this invention on the total phenols and total ketones of licorice were tested. The results showed that the total phenol content in the fresh licorice sample was 0.2198 mg RE / g dw, which represents the total phenol content per gram of dry weight sample, expressed as milligram quercetin equivalents. The total flavonoid content in the fresh licorice sample was 0.2756 mg RE / g dw, which represents the total flavonoid content per gram of dry weight sample, expressed as milligram gallic acid equivalents. The total phenol content in the dried licorice sample was 0.2104 mg RE / g dw, and the total flavonoid content in the fresh licorice sample was 0.2698 mg RE / g dw. This may be because the drying time of the drying method of this invention is very short, ensuring the quality and drying efficiency of licorice, minimizing the loss of medicinal components, avoiding the loss of heat-sensitive components, and effectively solving problems such as poor rehydration properties, large nutrient loss, and unsatisfactory taste, color, and flavor of the material. At the same time, it reduces the degree of oxidative denaturation of the components.

[0075] The drying method of this invention combines infrared drying and heat pump drying alternately, significantly shortening the drying cycle for achieving a safe moisture content in licorice. This is likely because: ① Activating the infrared drying system at 45°C generates far-infrared radiation in the 5-20 μm band and heats for 3 minutes, allowing simultaneous thermal effects to form on both the deep and surface layers of the licorice; ② Activating the heat pump drying system with horizontal airflow, setting the temperature to 45°C, and heating for 3 minutes with a dehumidifying fan speed of 5 m / s, increases the activity of water molecules, weakens the binding forces between water molecules, and breaks internal chemical bonds; ③ Activating the heat pump drying system with vertical, zigzag airflow, setting the temperature to 45°C, and heating for 4 minutes with a dehumidifying fan speed of 3 m / s, converts bound water within the cells into more fluid free water, reducing the internal diffusion boundary of the material and enhancing mass and heat transfer efficiency; ④ Activating both the infrared drying system and the heat pump drying system, setting the temperature to 45°C, generates far-infrared radiation in the 5-20 μm band, and heats for 2 minutes... When the dehumidifier is turned off, the licorice absorbs heat through heat transfer. The heat is transferred from the outside to the inside, and the moisture is transferred from the inside to the outside, gradually reaching the critical moisture content.

[0076] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0077] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. An infrared heat pump dryer, characterized in that, include: The drying chamber is equipped with a weighbridge inside, and a drying rack is installed above the weighbridge. The drying rack has multiple drying trays for placing materials. The drying chamber is equipped with an air inlet and an air outlet. A heat pump drying system includes a heat pump drying chamber and an evaporator, compressor, and condenser installed in the heat pump drying chamber. Humid air in the drying chamber enters the heat pump drying chamber through the exhaust vent and return air duct. After being dried, dehydrated, and heated by the heat pump, the air is transported back to the drying chamber through the supply air duct and the supply air vent. Low-temperature, low-pressure refrigerant gas is compressed by the compressor into high-temperature, high-pressure refrigerant gas, enters the condenser to condense into refrigerant liquid, and then enters the evaporator to evaporate into refrigerant gas. An infrared drying system includes a pair of infrared drying racks and a pair of carbon fiber infrared radiation plate assemblies. The pair of infrared drying racks are mounted on both sides of the drying rack and located outside the weighbridge. One infrared drying rack is equipped with a carbon fiber infrared radiation plate assembly via a lifting structure. The carbon fiber infrared radiation plate assembly includes multiple carbon fiber infrared radiation plates, which can rotate synchronously relative to the infrared drying rack. One carbon fiber infrared radiation plate is located below a drying tray, and any pair of carbon fiber infrared radiation plates forms a gap. An air supply chamber is provided outside the drying chamber, and the air box of the air supply chamber is connected to the air supply pipe; The air outlet includes a first air outlet and a plurality of second air outlets. The first air outlet is located at the top of the drying chamber and directly above the drying rack. The plurality of second air outlets are located on one side wall of the drying chamber. The plurality of second air outlets are connected to the air supply pipe through the air box of the air supply chamber. The first air outlet and the second air outlet are respectively equipped with a first air supply fan and a second air supply fan. The exhaust vent includes a first exhaust vent and a second exhaust vent. The first exhaust vent and the second exhaust vent are located on the upper and lower parts of another side wall of the drying chamber and are not on the same side wall as the multiple second air supply vents. The first exhaust vent and the second exhaust vent are respectively equipped with an upper exhaust humidifier and a lower exhaust humidifier. The air box of the air supply chamber is connected to multiple second air outlets through multiple reduced-diameter air outlet sections. A ceramic heating plate is provided inside the air box on the opposite side of the multiple reduced-diameter air outlet sections. The infrared drying rack includes an upper frame and a lower frame. The upper frame is a U-shaped frame, and the carbon fiber infrared radiation plate assembly is provided between a pair of vertical sections of the upper frame. The lower part of the pair of vertical sections of the upper frame also has a pair of elongated notches. The lower frame is an L-shaped frame, and the horizontal part of the lower frame is fixed to the ground by anchor bolts. The vertical part of the lower frame is located outside the upper frame. The inner side of the vertical part of the lower frame has a vertical guide groove, and the outer side of the upper frame has a guide block. The guide groove and the guide block cooperate. The lower frame has a bearing seat, and a pair of horizontal rotating shafts are parallel to each other through the bearing seat. The two ends of the horizontal rotating shafts extend to a pair of elongated notches. One of the horizontal rotating shafts rotates under the drive of a first motor. The lifting structure includes two lifting components. One lifting component is located in an elongated notch. The lifting component includes a pair of racks and a pair of gears. The pair of racks are located on opposite sidewalls of the elongated notch, and the pair of gears are located at the same end of a pair of horizontal rotating shafts. The pair of gears mesh with each other and respectively mesh with the pair of racks.

2. The infrared heat pump dryer as described in claim 1, characterized in that, The upper frame is equipped with multiple horizontal rollers through multiple pairs of bearings. Each horizontal roller is equipped with a carbon fiber infrared radiation plate. One of the horizontal rollers rotates under the drive of a second motor, and the multiple horizontal rollers are linked together through a linkage structure.

3. An infrared heat pump drying method, characterized in that, The infrared heat pump dryer according to claim 2 includes: Step 1: Move the drying rack above the weighbridge, and move a pair of infrared drying racks to both sides of the drying rack and outside the weighbridge; Step 2: Lay the material on each drying tray, attach at least one first temperature sensor to the surface of the material, embed at least one second temperature sensor inside the material, weigh it, and calculate the initial weight of the material. Step 3: Adjust the height of the pair of carbon fiber infrared radiation plates so that they are close to the drying tray above. Start the infrared drying system to perform radiation heating until the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the first temperature difference threshold. Step 4: Turn off the infrared drying system, adjust the height of the pair of carbon fiber infrared radiation plates so that they are in the middle of the upper and lower drying trays, start the second air supply fan of the heat pump drying system for conduction heating, start the upper exhaust fan and lower exhaust fan of the heat pump drying system until the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the second temperature difference threshold, and the second temperature difference threshold is lower than the first temperature difference threshold. Step 5: Start the infrared drying system for radiant heating, and simultaneously start the first and second air supply fans of the heat pump drying system for conductive heating. Turn off the upper and lower exhaust fans of the heat pump drying system, weigh the material, and calculate the real-time weight of the material until the moisture content of the material is reduced to the target moisture content threshold.

4. The infrared heat pump drying method as described in claim 3, characterized in that, When the difference between the average temperature detected by the first temperature sensor and the average temperature detected by the second temperature sensor is less than the second temperature difference threshold and the time t taken is greater than the preset time t0, step four further includes: Adjust the angle of a pair of carbon fiber infrared radiation plates, so that one set of carbon fiber infrared radiation plates rotates upward by 40~60° and the other set of carbon fiber infrared radiation plates rotates downward by 40~60°. Switch to start the first air blower of the heat pump drying system for conduction heating. Continue to start the upper exhaust fan and lower exhaust fan of the heat pump drying system, weigh, and calculate the real-time weight of the material until the moisture content of the material is reduced to the first moisture content threshold. Adjust the angle of a pair of carbon fiber infrared radiation plates, so that one set of carbon fiber infrared radiation plates rotates downward by 40~60° and the other set rotates upward by 40~60°. Continue to start the first air blower of the heat pump drying system for conduction heating. Continue to start the upper and lower exhaust fans of the heat pump drying system. Weigh and calculate the real-time weight of the material until the moisture content of the material decreases to the second moisture content threshold. The second moisture content threshold is higher than the target moisture content threshold and lower than the first moisture content threshold. Adjust the angle of the pair of carbon fiber infrared radiation plates to return them to horizontal. Adjust the height of the pair of carbon fiber infrared radiation plates so that they are positioned between the upper and lower drying trays. Proceed to step five.

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