Cascaded high-temperature open-closed loop drying all-in-one machine

Abstract

The invention relates to a cascade high-temperature open-closed loop drying all-in-one machine which comprises a shell, a drying system, a compression device, a heat exchange device, a sensing system and a control system. According to the all-in-one machine, materials are dried through the drying system arranged in the machine body, the temperature and humidity in the machine body are monitored and adjusted through the sensing system and the control system, and switching of an open-loop working mode and a closed-loop working mode is achieved. The drying system consists of a heat exchange box and a drying fan; the compression device comprises a compressor, a liquid storage tank and a gas-liquid separator; the heat exchange device comprises a micro-channel heat exchanger, a first evaporator and a second evaporator. The control system determines the drying temperature value when the machine body is started according to the characteristics and the thickness of materials, and the control system achieves accurate control over the temperature and the humidity in the drying process by switching open-closed loop working modes and adjusting the drying temperature and the rotating speed of the drying fan. The device has the characteristics of high efficiency, energy conservation, environmental protection and uniform drying, and is suitable for drying treatment of various materials.

Description

Technical Field

[0001] The invention relates to the technical field of drying, and in particular to a cascade high-temperature open-closed loop drying all-in-one machine. Background Art

[0002] Drying equipment is one of the essential equipment in industrial production and daily life. Traditional drying equipment usually adopts open-loop or closed-loop system, which cannot achieve high-temperature drying and precise control, resulting in poor drying effect and high energy consumption.

[0003] Chinese patent announcement number: CN108489144B ​​discloses a granular material dryer, including a drying tunnel, a lower heating component, an upper heating component and a heat pump main unit. The lower heating component is located below the drying tunnel, and several components are arranged along the length of the drying tunnel to provide hot air to the drying tunnel. The upper heating component is located above the drying tunnel, and several components are arranged along the length of the drying tunnel to provide hot air to the drying tunnel. A heat pump main unit is provided, which is connected to each lower heating component and upper heating component, and heat is supplied to each lower heating component and upper heating component respectively. Compared with the prior art, the present invention adopts a cascade heat pump cycle to meet the high temperature requirements of drying. The present invention adopts a multi-connected heat exchanger arrangement and a connecting pipe network. The air does not need to be centrally heated and then distributed using air ducts. In the present invention, the fresh air is preheated by a supercooler to improve the circulation efficiency. It can be seen that the material dryer still has the problem that the system cannot accurately control the drying temperature and humidity, the drying effect is unstable, the drying efficiency is low, and the energy consumption is high. Summary of the invention

[0004] To this end, the present invention provides a cascade high-temperature open-closed loop drying all-in-one machine to overcome the problems in the prior art of being unable to accurately control drying temperature and humidity, unstable drying effect, low drying efficiency, and high energy consumption.

[0005] To achieve the above object, the present invention provides a cascade high-temperature open-closed loop drying machine, comprising:

[0006] The host includes a housing, a drying system, a compression device, a heat exchange device, a sensor system and a control system;

[0007] The housing comprises a bracket and a plurality of protective plates, wherein the protective plates are respectively inserted in the gaps in the bracket to protect the internal parts of the device;

[0008] A drying system is arranged at the bottom and side of the main machine to dry the material, and each component in the drying system is connected in sequence through metal pipes;

[0009] A compression device, arranged at the bottom of the main unit, for compressing and storing refrigerant;

[0010] A heat exchange device, arranged above the compression device, for circulating heat exchange between the condensing agent and the air;

[0011] A sensor system is provided on the drying system to monitor the temperature and humidity inside the drying system and the temperature and humidity of the material;

[0012] A control system, arranged on the housing, for controlling the drying system, the compression device, the heat exchange device, the sensor system and the switching of the open-loop and closed-loop working modes;

[0013] The return air duct is used to connect the heat exchange box and the main unit, and circulate the gas in the heat exchange box back to the main unit during closed-loop drying;

[0014] The control system comprises an electric box door and a display screen, wherein the electric box door is arranged on the bracket to protect the electric wires, and the display screen is arranged on the electric box door to display various parameters;

[0015] The control system determines the drying temperature value when the machine body is started according to the material characteristics and thickness.

[0016] Furthermore, the drying system comprises:

[0017] A heat exchange box is arranged on the side of the main machine, and a plurality of drying plates are arranged in the heat exchange box for containing and drying materials;

[0018] A drying fan, arranged at the bottom of the main unit and connected to the heat exchange box, is used to promote the flow of gas in the machine body and transport the high-temperature gas to the heat exchange box;

[0019] The compression device comprises:

[0020] A compressor, used to compress the refrigerant, wherein the compressor is divided into a low-temperature compressor and a high-temperature compressor;

[0021] A liquid storage tank connected to the compressor inlet for storing refrigerant;

[0022] The gas-liquid separator is connected to the liquid storage tank to separate the hot steam from the refrigerant.

[0023] Furthermore, the heat exchange device comprises:

[0024] A microchannel heat exchanger connected to the compressor outlet for releasing heat to the outside;

[0025] The first evaporator is connected to the microchannel heat exchanger. During open-loop drying, the first evaporator is smoothly connected to the outside, efficiently absorbs the heat of the outdoor air, promotes the gasification of the refrigerant and absorbs heat, fully transfers the heat of the outdoor air to the refrigerant, and then accurately returns it to the compressor through the four-way valve to achieve heat recovery and utilization; during the closed-loop drying stage, the first evaporator is isolated from the outside and becomes a liquid storage device to temporarily store the refrigerant, effectively reducing the interference of the outdoor environment;

[0026] The second evaporator is connected to the first evaporator. During closed-loop drying, the second evaporator serves as a liquid storage tank to receive the liquid refrigerant condensed by the microchannel heat exchanger; during open-loop drying, the second evaporator transports the refrigerant to the first evaporator, connecting the refrigerant circulation process.

[0027] Furthermore, when the sensing system detects that the material humidity value reaches the preset switching humidity range, the control system switches from the open-loop working mode to the closed-loop working mode. When switching from the open-loop working mode to the closed-loop working mode, the drying temperature value at the time of machine startup is analyzed and compared with the switching drying standard temperature range to determine the drying temperature value when switching to the closed-loop working mode.

[0028] Further, determining the drying temperature value when switching to the closed-loop working mode includes, if the drying temperature value when the drying machine is started is less than the switching drying standard temperature range, reducing the drying temperature value when switching to the closed-loop working mode;

[0029] If the drying temperature value when the drying machine is started is greater than the switching drying standard temperature range, the drying temperature value when switching to the closed-loop working mode is increased;

[0030] If the drying temperature value when the drying machine is started is in the switching drying standard temperature range, the initial drying temperature initial standard value when switching to the closed-loop working mode is used for switching.

[0031] Furthermore, the closed-loop working mode is entered according to the determined drying temperature value when switching to the closed-loop working mode. The control system records the material humidity value at each preset time interval, and records the actual humidity change between each two times. After recording four times in a row, the average value of the actual humidity change is calculated, and the average value of the actual humidity change is compared and analyzed with the preset standard humidity change range.

[0032] Furthermore, when the average value of the actual humidity change is less than the preset standard humidity change range, it is determined that the current working mode does not meet the drying requirements and the drying temperature value needs to be increased;

[0033] When the average value of the actual humidity change is greater than the preset standard humidity change range, it is determined that the current working mode does not meet the drying requirements and the drying temperature value needs to be reduced;

[0034] When the average value of the actual humidity change is within the preset standard humidity change range, it is determined that the current working mode meets the drying requirements and the drying temperature value remains unchanged.

[0035] Furthermore, when the increased temperature value is greater than the switching drying standard temperature interval, the maximum value of the switching drying standard temperature interval is used as the increased drying temperature value, and the speed of the fan is increased at the same time;

[0036] When the reduced temperature value is greater than the switching drying standard temperature interval, the minimum value of the switching drying standard temperature interval is used as the reduced drying temperature value, and the speed of the fan is reduced at the same time.

[0037] Further, when the increased temperature value is greater than the switching drying standard temperature interval, the maximum value of the switching drying standard temperature interval is used as the increased drying temperature value, and the speed of the drying fan is increased at the same time to increase the humidity reduction speed, and the increased drying fan speed value is determined according to the product of the difference between the increased temperature difference value and the maximum value of the drying standard temperature interval and the preset increase speed ratio parameter;

[0038] When the reduced temperature value is greater than the switching drying standard temperature interval, the minimum value of the switching drying standard temperature interval is used as the reduced drying temperature value, and the speed of the drying fan is reduced at the same time to reduce the humidity reduction rate. The reduced drying fan speed value is determined according to the difference between the reduced temperature difference and the minimum value of the drying standard temperature interval, and the product of the preset speed reduction ratio parameter.

[0039] Furthermore, when the average material humidity value stably falls within the standard humidity value range and the monitoring results meet the standard for five consecutive times, the sensing system sends a drying completion signal to the control system, and the control system then shuts down each component in an orderly manner.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] First, when the drying machine of the present invention is started, the compressor is started first, which effectively improves the starting efficiency and reduces the energy loss during the starting process. The refrigerant is compressed and transported to the microchannel heat exchanger 41 under the action of the compressor. This process not only improves the heat exchange efficiency, but also adopts an advanced cascade system to expand the range of working air outlet temperature through cascade design. It can operate under ultra-low temperature conditions, avoiding the problems of poor heating efficiency and low air outlet temperature range during drying in traditional technologies, and realizing precise temperature control and fast and efficient heat conversion; the present invention can achieve high-temperature drying of 70°C to 120°C, meeting the requirements of various radiators.

[0042] The drying system uses metal pipes to connect the components in sequence, which effectively improves the efficiency of heat transfer and reduces energy loss. At the same time, the structural design simplifies the installation and maintenance process of the equipment and reduces operating costs.

[0043] Secondly, the refrigerant releases heat in the microchannel heat exchanger 41 and then flows into the first evaporator 42. This process design ensures the effective use of heat and reduces heat waste. Through the open-loop working mode, the outdoor fan runs at full capacity to force the outdoor fresh air to flow through the first evaporator 42. This innovative design enables the heat carried by the outdoor air to be efficiently transferred to the refrigerant, promoting the refrigerant to vaporize and absorb heat to complete the heat exchange. This not only improves the heat exchange efficiency, but also achieves efficient use of heat and reduces energy consumption.

[0044] The heat exchange device of the present invention includes a first evaporator and a second evaporator, which can efficiently recover and utilize heat in open-loop and closed-loop drying modes. In the open-loop drying mode, the first evaporator can fully absorb the heat of the outdoor air to achieve efficient utilization of heat; while in the closed-loop drying mode, the second evaporator is used as a liquid storage tank to temporarily store refrigerant, effectively reducing outdoor environmental interference and ensuring the stability of the drying process.

[0045] Furthermore, the control system in the present invention can determine the drying temperature value when the machine body is started according to the material characteristics and thickness, and automatically switch the drying mode according to the change of the material humidity value, adjust the drying temperature and fan speed, and ensure the best drying effect. This intelligent control strategy not only improves the drying efficiency, but also greatly reduces energy consumption, which is in line with the development trend of green environmental protection.

[0046] In addition, the present invention monitors the temperature and humidity in the machine body and the temperature and humidity of the material in real time through the sensing system, ensuring accurate control of the drying process. When the average humidity value of the material falls stably into the standard humidity value range and the monitoring results meet the standard for 5 consecutive times, the system can automatically send a drying completion signal and shut down each component in an orderly manner, thereby improving the safety and reliability of the equipment.

[0047] In summary, the present invention has the advantages of high drying efficiency, low energy consumption, high degree of automation, good drying quality, simple operation, long equipment life, etc. It provides a new technical solution for the drying industry and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic cross-sectional structure diagram of the cascade high-temperature open-closed loop drying machine of the present invention;

[0049] Figure 2 It is a structural schematic diagram of the cascade high-temperature open-closed loop drying integrated machine of the present invention;

[0050] Figure 3 It is a schematic diagram of the main machine side view of the cascade high-temperature open-closed loop drying machine of the present invention;

[0051] Figure 4 This is a schematic diagram of the main structure of the cascade high-temperature open-closed loop drying machine of the present invention. DETAILED DESCRIPTION

[0052] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0054] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0055] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] See also Figure 1-Figure 4 As shown, Figure 1 It is a schematic cross-sectional structure diagram of the cascade high-temperature open-closed loop drying machine of the present invention; Figure 2 It is a structural schematic diagram of the cascade high-temperature open-closed loop drying integrated machine of the present invention; Figure 3 It is a schematic diagram of the main machine side view of the cascade high-temperature open-closed loop drying machine of the present invention; Figure 4 This is a schematic diagram of the main structure of the cascade high-temperature open-closed loop drying machine of the present invention.

[0057] A cascade high-temperature open-closed loop drying machine, which dries and dehumidifies materials inside the machine body by using cyclic heat exchange between air and refrigerant and switching between open-closed loop working modes, including:

[0058] A host 7, which includes a housing 1, a drying system 2, a compression device 3, a heat exchange device 4, a sensor system 5 and a control system 6;

[0059] The housing 1 comprises a bracket 11 and a plurality of protective plates 12, wherein the protective plates 12 are respectively inserted into the gaps in the bracket 11 to protect the internal parts of the device;

[0060] The drying system 2 is arranged at the bottom and side of the main machine 7 to dry the material. The components of the drying system 2 are connected in sequence through metal pipes.

[0061] A compression device 3, arranged at the bottom of the main unit 7, for compressing and storing refrigerant;

[0062] The heat exchange device 4 is arranged above the compression device 3 and is used for circulating heat exchange between the condensing agent and the air;

[0063] A sensor system 5 is provided on the drying system 2 to monitor the temperature and humidity inside the drying system and the temperature and humidity of the material;

[0064] A control system 6, arranged on the housing 1, for controlling the drying system 2, the compression device 3, the heat exchange device 4, the sensor system 5 and the switching of the open-loop and closed-loop working modes;

[0065] The return air duct 8 is used to connect the heat exchange box 21 and the main unit 7, and circulate the gas in the heat exchange box 21 back to the main unit 7 during closed-loop drying;

[0066] The control system 6 includes an electric box door 61 and a display screen 62. The electric box door 61 is arranged on the bracket 11 to protect the wires. The display screen 62 is arranged on the electric box door 61 to display various parameters.

[0067] The control system 6 determines the drying temperature value when the machine is started according to the material characteristics and thickness.

[0068] Furthermore, the drying system 2 comprises:

[0069] The heat exchange box 21 is arranged on the side of the main machine 7, and a plurality of drying plates 211 are arranged in the heat exchange box 21 for containing and drying materials;

[0070] A drying fan 22 is provided at the bottom of the main unit 7 and connected to the heat exchange box 21 to promote the flow of gas in the machine body and transport the high-temperature gas to the heat exchange box 21;

[0071] The compression device 3 comprises:

[0072] A compressor, used to compress the refrigerant, the compressor is divided into a low temperature compressor 1 and a high temperature compressor 322;

[0073] A liquid storage tank 32, connected to the compressor inlet, for storing refrigerant;

[0074] A gas-liquid separator 33, connected to the liquid storage tank 32, is used to separate the hot steam from the refrigerant;

[0075] Furthermore, the heat exchange device 4 comprises:

[0076] A microchannel heat exchanger 41 is connected to the compressor outlet to release heat to the outside;

[0077] The microchannel heat exchanger 41 adopts a cascade design to expand the range of working air outlet temperature.

[0078] The first evaporator 42 is connected to the microchannel heat exchanger 41. During the open-loop drying, the first evaporator 42 is smoothly connected to the outside, efficiently absorbs the heat of the outdoor air, promotes the gasification of the refrigerant and absorbs heat, fully transfers the heat of the outdoor air to the refrigerant, and then accurately returns it to the compressor through the four-way valve to realize heat recovery and utilization; during the closed-loop drying stage, the first evaporator 42 is isolated from the outside and becomes a liquid storage device to temporarily store the refrigerant, effectively reducing the interference of the outdoor environment;

[0079] The second evaporator 43 is connected to the first evaporator 42. During closed-loop drying, the second evaporator 43 acts as a liquid storage tank 32 to receive the liquid refrigerant condensed by the microchannel heat exchanger 41; during open-loop drying, the second evaporator 43 transports the refrigerant to the first evaporator 42, connecting the refrigerant circulation process.

[0080] Specifically, the present invention adopts an advanced cascade system to expand the range of working air outlet temperature through cascade design, and can operate under ultra-low temperature conditions, avoiding the problems of poor heating efficiency and low air outlet temperature range during drying in traditional technologies, and realizing precise temperature control and fast and efficient heat conversion; the present invention can achieve high-temperature drying of 70°C to 120°C, meeting the requirements of various radiators.

[0081] Before using the cascade high-temperature open-closed loop drying machine, the operator should first conduct a detailed inspection of the machine. Check whether the bracket 11 of the housing 1 is stable, whether the protective plate 12 is loose, deformed or damaged, and ensure that the internal parts are properly protected to prevent dust and moisture from invading and affecting the operation of the equipment. Open the electrical box door 61, check whether the wires are tightly connected, whether there is any damage or short circuit, confirm that the display of each sensor system 5 is normal, and ensure that the electrical system is stable and reliable.

[0082] The tea leaves to be dried are placed evenly on a multi-layer breathable material tray in the heat exchange box 21, and the thickness value of each layer of tea leaves and the initial drying temperature value are set with initial standard values ​​according to the types of tea leaves collected.

[0083] Among them, the initial standard value range of the thickness of each layer of tea leaves is 2-3 cm, and the initial standard value range of the initial drying temperature is 40-55°C.

[0084] Green tea is rich in various nutrients and aromatic substances, and too high a temperature can easily damage its quality. Therefore, the temperature drying range used is 40-55°C, which ensures that the tea can be effectively dried while maintaining the quality of the tea after drying. At the same time, the thickness of each layer of tea is set to 2-3 cm to prevent the tea from being too thin, resulting in loss of aroma during the drying process, or too thick, resulting in uneven drying.

[0085] In this embodiment, the initial standard value of the thickness of each layer of tea is set to 2.5 cm, and the initial standard value of the initial drying temperature is set to 45°C; the initial humidity value of the tea is 65%, and the standard humidity value range of the tea is 5%-8%. The total drying time is estimated to be about 4-6 hours, and the open-loop drying mode is selected as the starting working mode. After saving the set parameters, prepare to start the equipment.

[0086] For the thickness of tea leaves, a standard thickness range is set according to the determined initial standard value.

[0087] The actual thickness of each layer of tea leaves is obtained according to the image detection device, and the average thickness is calculated, and the calculated average thickness is compared with the standard thickness range to determine the drying temperature value when the drying machine is started;

[0088] If the actual average value of the thickness is less than the standard thickness range, the initial standard value of the initial drying temperature is reduced to obtain the drying temperature value when the drying machine is started;

[0089] If the actual average value of the thickness is greater than the standard thickness range, the initial standard value of the initial drying temperature is increased to obtain the drying temperature value when the drying machine is started;

[0090] If the actual average value of the thickness is within the standard thickness range, the initial standard value of the initial drying temperature is used as the drying temperature value when the drying machine is started.

[0091] In this embodiment, the standard thickness range is set to 2.5±0.1 cm.

[0092] The actual thickness of each layer of tea leaves is obtained according to the image detection device, and the average thickness is calculated, and the calculated average thickness is compared with the standard thickness range;

[0093] When the initial standard value of the initial drying temperature is reduced, the reduced value is determined by multiplying the difference between the initial standard value of the thickness of each layer of tea leaves and the actual average thickness by a preset reduction temperature ratio parameter.

[0094] For example, the actual average thickness is set to 2.3 cm, and the temperature ratio parameter is reduced to 10. Then, the drying temperature value when the drying machine is started is 45-(2.5-2.3)×10=43°C.

[0095] When the initial standard value of the initial drying temperature is increased, the increased value is determined by multiplying the difference between the initial standard value of the thickness of each layer of tea leaves and the average value of the actual thickness by a preset increase temperature ratio parameter.

[0096] For example, if the actual average thickness is set to 2.7 cm and the temperature ratio parameter is increased to 11, the drying temperature value when the drying machine is started is 45+(2.7-2.5)×11=47.2°C.

[0097] Start the equipment, the compressor of the drying machine starts first, compresses the refrigerant and delivers it to the microchannel heat exchanger 41, where the refrigerant releases heat to the outside and then flows into the first evaporator 42. At this time, the open-loop working mode is selected, and the outdoor fan runs at full capacity, continuously forcing outdoor fresh air to flow through the first evaporator 42. The heat carried by the outdoor air is efficiently transferred to the refrigerant, which promotes the refrigerant to gasify and absorb heat. After the heat exchange is completed, it is accurately returned to the compressor through the four-way valve to start the first round of drying cycle; at the same time, the drying fan 22 vigorously sucks in hot air from the side of the heat exchange box 21, allowing the heat-saturated air to evenly blow over the tea leaves, and delivers the hot air to the designated area as needed, helping to dry the tea leaves in all directions.

[0098] When the drying machine of the present invention is started, the compressor is started first, which effectively improves the starting efficiency and reduces the energy loss during the starting process. The refrigerant is compressed by the compressor and transported to the microchannel heat exchanger 41. This process not only improves the heat exchange efficiency, but also adopts an advanced cascade system to expand the range of working air outlet temperature through cascade design, and can operate under ultra-low temperature conditions, avoiding the problems of poor heating efficiency and low air outlet temperature range during drying in traditional technologies, and realizing precise temperature control and fast and efficient heat conversion; the present invention can achieve high-temperature drying of 70°C to 120°C, meeting the requirements of various radiators.

[0099] Secondly, the refrigerant releases heat to the outside in the microchannel heat exchanger 41 and then flows into the first evaporator 42. This process design ensures the effective use of heat and reduces heat waste. Through the open-loop working mode, the outdoor fan runs at full capacity to force the outdoor fresh air to flow through the first evaporator 42. This innovative design enables the heat carried by the outdoor air to be efficiently transferred to the refrigerant, promoting the refrigerant to gasify and absorb heat, and complete the heat exchange. This not only improves the heat exchange efficiency, but also realizes the efficient use of heat and reduces energy consumption.

[0100] In addition, the drying fan 22 of the present invention vigorously sucks in hot air from the side of the heat exchange box 21, so that the hot air can evenly blow over the tea leaves. This design effectively solves the problems caused by uneven heating in the prior art, such as uneven drying and warping of tea leaves. At the same time, the hot air is transported to a predetermined area as needed, which helps the tea leaves dry in all directions and improves the drying quality and efficiency.

[0101] The multiple temperature sensors and humidity sensors in the sensor system 5 monitor the temperature and humidity information of key parts inside the machine in real time, and the data is quickly transmitted back to the control system 6. As the drying process progresses, the moisture in the tea leaves evaporates slowly, and the humidity in the drying machine gradually rises. When it is detected that the average humidity of the tea leaves is in the preset switching humidity range of 20%-30%, the working mode switching signal is triggered to switch from the open-loop working mode to the closed-loop working mode.

[0102] The control system 6 automatically determines the drying temperature value according to the material characteristics and thickness, and automatically switches the drying mode when the material humidity value reaches the preset switching humidity range, thereby realizing the automated control of the drying process, reducing the difficulty of operation, reducing manual intervention, and improving production efficiency.

[0103] When switching from open-loop mode to closed-loop mode,

[0104] If the drying temperature value when the drying machine is started is lower than the switching drying standard temperature range, the drying temperature value when switching to the closed-loop working mode is reduced;

[0105] If the drying temperature value when the drying machine is started is greater than the switching drying standard temperature range, the drying temperature value when switching to the closed-loop working mode is increased;

[0106] If the drying temperature value when the drying machine is started is in the switching drying standard temperature range, the initial drying temperature initial standard value when switching to the closed-loop working mode is used for switching.

[0107] In this embodiment, it is set that the corresponding temperature when the compressor works at standard power is 45°C, and the initial standard value of the initial drying temperature in the open-loop working mode is 45°C. The corresponding initial standard value of the initial drying temperature when switching to the closed-loop working mode is 50°C, and the switching drying standard temperature range when switching to the closed-loop working mode is 50±5°C.

[0108] Compare the actual drying temperature value when the drying machine is started with the initial drying standard temperature range when switching to the closed-loop working mode;

[0109] When the drying temperature value when switching to the closed-loop working mode is reduced, the reduced value is determined by multiplying the difference between the actual drying temperature value when the drying machine is started and the drying temperature value when switching to the closed-loop working mode by a preset temperature reduction ratio parameter.

[0110] For example, the actual drying temperature value when the drying machine is started is set to 41°C, and the temperature reduction ratio parameter is 0.5. Then, the drying temperature value when switching to the closed-loop working mode is 50-(45-41)×0.5=48°C.

[0111] When the drying temperature value when switching to the closed-loop working mode is increased, the increased value is determined by multiplying the difference between the actual drying temperature value when the drying machine is started and the drying temperature value when switching to the closed-loop working mode by a preset increase temperature ratio parameter.

[0112] For example, the actual drying temperature value when the drying machine is started is set to 44°C, and the temperature increase ratio parameter is 2. Then the drying temperature value when switching to the closed-loop working mode is 50+(45-44)×2=52°C.

[0113] During the drying process, the design of the first evaporator 42 and the second evaporator 43 realizes flexible switching between the open-loop drying mode and the closed-loop drying mode. In the open-loop drying mode, the first evaporator 42 can efficiently absorb the heat of the outdoor air to achieve heat recovery; in the closed-loop drying mode, the first evaporator 42 acts as a liquid storage tank 32 to temporarily store refrigerant, effectively reducing outdoor environmental interference and ensuring the stability of the drying process.

[0114] The drying machine enters the closed-loop working mode according to the determined drying temperature value when switching to the closed-loop working mode. The control system 6 records the tea humidity value once every 6 minutes, and records the actual humidity change between each two times. The preset standard humidity change is 1% every 6 minutes. After four consecutive records, the average value of the actual humidity change is calculated, and the average value of the actual humidity change is compared with the preset standard humidity change interval;

[0115] When the average value of the actual humidity change is less than the preset standard humidity change range, it is determined that the current working mode does not meet the drying requirements and the drying temperature value needs to be increased;

[0116] When the average value of the actual humidity change is greater than the preset standard humidity change range, it is determined that the current working mode does not meet the drying requirements and the drying temperature value needs to be reduced;

[0117] When the average value of the actual humidity change is within the preset standard humidity change range, it is determined that the current working mode meets the drying requirements and the drying temperature value remains unchanged.

[0118] In this embodiment, the preset standard humidity variation range is 1%±0.01%.

[0119] The humidity value of each layer of tea leaves is obtained by using a microwave moisture detector, and the average humidity value is calculated. After recording four times in a row, the average actual humidity change is obtained, and the average actual humidity change is compared with the preset standard humidity change range;

[0120] When the drying temperature value is reduced, the reduced value is determined according to the product of the difference between the actual humidity change average value and the preset standard humidity change value and the preset humidity reduction ratio parameter.

[0121] For example, the drying temperature value when switching to the closed-loop working mode is set to 50°C, the actual average humidity change is 1.05%, and the humidity reduction ratio parameter is 20, then the reduced drying temperature value is 50-(1.05%-1%)×20=49°C.

[0122] When the drying temperature value is increased, the increased drying temperature value is determined according to the product of the difference between the actual humidity change average value and the preset standard humidity change value and the preset humidity increase ratio parameter.

[0123] For example, the drying temperature value when switching to the closed-loop working mode is set to 42°C, the actual average humidity change is 0.95%, and the humidity increase ratio parameter is 30. The increased drying temperature value is 50+(1%-0.95%)×30=51.5°C.

[0124] When the increased temperature value is greater than the switching drying standard temperature interval, the maximum value of the switching drying standard temperature interval is used as the increased drying temperature value, and the rotation speed of the drying fan 22 is increased to increase the humidity reduction speed. The increased rotation speed value of the drying fan 22 is determined according to the product of the difference between the increased temperature difference value and the maximum value of the drying standard temperature interval and the preset increase rotation speed ratio parameter;

[0125] For example, the increased temperature value is set to 60°C, and the maximum value of the standard drying temperature range of 55°C is used as the increased drying temperature value. The initial speed value of the drying fan 22 is 1000 rpm, and the preset increase speed ratio parameter is 10. Then the increased speed value of the drying fan 22 is 1000+(60-55)×10=1050 rpm.

[0126] When the reduced temperature value is greater than the switching drying standard temperature interval, the minimum value of the switching drying standard temperature interval is used as the reduced drying temperature value, and the rotation speed of the drying fan 22 is reduced to reduce the humidity reduction speed. The reduced rotation speed value of the drying fan 22 is determined according to the product of the difference between the reduced temperature difference value and the minimum value of the drying standard temperature interval and the preset rotation speed reduction ratio parameter;

[0127] For example, the reduced temperature value is set to 35°C, and the minimum value of the switching drying standard temperature range of 40°C is used as the reduced drying temperature value. The initial value of the drying fan 22 speed is 1000 rpm, and the preset speed reduction ratio parameter is 20. Then the reduced speed value of the drying fan 22 is 1000-(40-35)×10=950 rpm.

[0128] After adjusting the drying temperature in the closed-loop working mode according to the above rules, the drying machine maintains the temperature stably for a period of time. As the drying process progresses, the moisture content of the tea leaves continues to decrease, getting closer to the standard humidity value range. When the average humidity of the tea leaves enters the 8%-10% range, the microwave moisture detector will provide real-time feedback on the humidity data of each layer of the tea leaves. When the average humidity of the tea leaves stably falls into the standard humidity value range of 5%-8%, and the monitoring results meet the standards for 5 consecutive times, the sensor system 5 sends a drying completion signal to the control system 6, and the control system 6 then shuts down the various components in an orderly manner. After the equipment is shut down, the drying box door is opened, and the operator carefully takes out the dried tea leaves.

[0129] The cascade high-temperature drying technology adopted by the present invention effectively overcomes the problems of low heating efficiency and high energy consumption of traditional drying equipment. Through the efficient cooperation of the compression device 3, the heat exchange device 4 and the air circulation system, heat recovery is achieved, the drying efficiency is greatly improved, and energy consumption is reduced, which is in line with the current development trend of energy conservation and emission reduction.

[0130] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cascade high-temperature open-closed loop drying machine, characterized in that: include, The host includes a housing, a drying system, a compression device, a heat exchange device, a sensor system and a control system; The housing comprises a bracket and a plurality of protective plates, wherein the protective plates are respectively inserted in the gaps in the bracket to protect the internal parts of the device; A drying system is arranged at the bottom and side of the main machine to dry the material, and each component in the drying system is connected in sequence through metal pipes; A compression device, arranged at the bottom of the main unit, for compressing and storing refrigerant; A heat exchange device, arranged above the compression device, for circulating heat exchange between the condensing agent and the air; A sensor system is provided on the drying system to monitor the temperature and humidity inside the drying system and the temperature and humidity of the material; A control system, arranged on the housing, for controlling the drying system, the compression device, the heat exchange device, the sensor system and the switching of the open-loop and closed-loop working modes; The return air duct is used to connect the heat exchange box and the main unit, and circulate the gas in the heat exchange box back to the main unit during closed-loop drying; The control system comprises an electric box door and a display screen, wherein the electric box door is arranged on the bracket to protect the electric wires, and the display screen is arranged on the electric box door to display various parameters; The control system determines the drying temperature value when the machine body is started according to the material characteristics and thickness.

2. The cascade high-temperature open-closed loop drying machine according to claim 1, characterized in that: The drying system comprises: A heat exchange box is arranged on the side of the main machine, and a plurality of drying plates are arranged in the heat exchange box for containing and drying materials; A drying fan, arranged at the bottom of the main unit and connected to the heat exchange box, is used to promote the flow of gas in the machine body and transport the high-temperature gas to the heat exchange box; The compression device comprises: A compressor, used to compress the refrigerant, wherein the compressor is divided into a low-temperature compressor and a high-temperature compressor; A liquid storage tank connected to the compressor inlet for storing refrigerant; The gas-liquid separator is connected to the liquid storage tank to separate the hot steam from the refrigerant.

3. The cascade high-temperature open-closed loop drying machine according to claim 2, characterized in that: The heat exchange device comprises: A microchannel heat exchanger connected to the compressor outlet for releasing heat to the outside; The first evaporator is connected to the microchannel heat exchanger. During open-loop drying, the first evaporator is smoothly connected to the outside, efficiently absorbs the heat of the outdoor air, promotes the gasification of the refrigerant and absorbs heat, fully transfers the heat of the outdoor air to the refrigerant, and then accurately returns it to the compressor through the four-way valve to achieve heat recovery and utilization; during the closed-loop drying stage, the first evaporator is isolated from the outside and becomes a liquid storage device to temporarily store the refrigerant, effectively reducing the interference of the outdoor environment; The second evaporator is connected to the first evaporator. During closed-loop drying, the second evaporator serves as a liquid storage tank to receive the liquid refrigerant condensed by the microchannel heat exchanger; during open-loop drying, the second evaporator transports the refrigerant to the first evaporator, connecting the refrigerant circulation process.

4. The cascade high-temperature open-closed loop drying machine according to claim 3, characterized in that: When the sensing system detects that the material humidity value reaches the preset switching humidity range, the control system switches from open-loop working mode to closed-loop working mode. When switching from open-loop working mode to closed-loop working mode, the drying temperature value at the time of machine startup is analyzed and compared with the switching drying standard temperature range to determine the drying temperature value when switching to closed-loop working mode.

5. The cascade high-temperature open-closed loop drying machine according to claim 4, characterized in that: Determine the drying temperature value when switching to closed-loop working mode, Including, if the drying temperature value when the drying machine is started is less than the switching drying standard temperature range, then the drying temperature value when switching to the closed-loop working mode is reduced; If the drying temperature value when the drying machine is started is greater than the switching drying standard temperature range, the drying temperature value when switching to the closed-loop working mode is increased; If the drying temperature value when the drying machine is started is in the switching drying standard temperature range, the initial drying temperature initial standard value when switching to the closed-loop working mode is used for switching.

6. The cascade high-temperature open-closed loop drying machine according to claim 5, characterized in that: The closed-loop working mode is entered according to the determined drying temperature value when switching to the closed-loop working mode. The control system records the material humidity value at preset intervals and records the actual humidity change between each two times. After four consecutive records, the average value of the actual humidity change is calculated, and the average value of the actual humidity change is compared and analyzed with the preset standard humidity change range.

7. The cascade high-temperature open-closed loop drying machine according to claim 6, characterized in that: When the average value of the actual humidity change is less than the preset standard humidity change range, it is determined that the current working mode does not meet the drying requirements and the drying temperature value needs to be increased; When the average value of the actual humidity change is greater than the preset standard humidity change range, it is determined that the current working mode does not meet the drying requirements and the drying temperature value needs to be reduced; When the average value of the actual humidity change is within the preset standard humidity change range, it is determined that the current working mode meets the drying requirements and the drying temperature value remains unchanged.

8. The cascade high-temperature open-closed loop drying machine according to claim 7, characterized in that: When the increased temperature value is greater than the switching drying standard temperature range, the maximum value of the switching drying standard temperature range is used as the increased drying temperature value, and the fan speed is increased at the same time; When the reduced temperature value is greater than the switching drying standard temperature interval, the minimum value of the switching drying standard temperature interval is used as the reduced drying temperature value, and the speed of the fan is reduced at the same time.

9. The cascade high-temperature open-closed loop drying machine according to claim 8, characterized in that: When the increased temperature value is greater than the switching drying standard temperature interval, the maximum value of the switching drying standard temperature interval is used as the increased drying temperature value, and the rotation speed of the drying fan is increased at the same time to increase the humidity reduction speed. The increased drying fan rotation speed value is determined according to the product of the difference between the increased temperature difference value and the maximum value of the drying standard temperature interval and the preset increase rotation speed ratio parameter; When the reduced temperature value is greater than the switching drying standard temperature interval, the minimum value of the switching drying standard temperature interval is used as the reduced drying temperature value, and the speed of the drying fan is reduced at the same time to reduce the humidity reduction rate. The reduced drying fan speed value is determined according to the difference between the reduced temperature difference and the minimum value of the drying standard temperature interval, and the product of the preset speed reduction ratio parameter.

10. The cascade high-temperature open-closed loop drying machine according to claim 9, characterized in that: When the average material humidity value falls stably within the standard humidity value range and the monitoring results meet the standard for five consecutive times, the sensor system sends a drying completion signal to the control system, and the control system then shuts down each component in an orderly manner.

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