Closed-loop heat pump dryer

Abstract

The utility model discloses a closed-loop heat pump dryer, which relates to the technical field of heat pump dryers and comprises a drying chamber, a compressor, double evaporators, a partition condenser, a waste heat recovery device, a fan, a humidity sensor, an airflow guide plate and a control unit. The double evaporators are formed by connecting a main evaporator and an auxiliary evaporator in series, the main evaporator is connected with a drying chamber air return pipeline, and the auxiliary evaporator is connected with a fresh air inlet; the subarea condenser is divided into a high-temperature area and a low-temperature area, and a heat distribution path is switched through a three-way valve; the waste heat recovery device conducts waste heat of the condenser to a fresh air pipeline through a heat exchange pipe. And the fan is used for driving airflow to circularly flow among the drying chamber, the double evaporators and the partition condenser. The system has the advantages that the design that the two evaporators are connected in series is adopted, the main evaporator treats return air humidity, the auxiliary evaporator precools fresh air, the dehumidification efficiency is improved, the two evaporators can exert respective advantages, and the overall dehumidification effect of the system is improved.

Description

Technical Field

[0001] This utility model relates to the field of heat pump dryer technology, specifically to a closed-loop heat pump dryer. Background Technology

[0002] Heat pump drying is a power-driven device used for drying. This equipment is a heat-lifting device. High-temperature heat pump drying units utilize the reverse Carnot cycle principle to absorb heat from the surrounding environment and transfer it to the object being heated (a high-temperature object). Its working principle is the same as that of a refrigeration machine, both operating according to the reverse Carnot cycle. The only difference is the operating temperature range.

[0003] Traditional dryers are energy-intensive, directly releasing hot and humid air during dehumidification, resulting in heat waste. This not only increases energy consumption but may also prolong the production cycle and affect overall work efficiency. Furthermore, the condenser of heat pump dryers is prone to frosting, which affects heat exchange efficiency and requires frequent defrosting, further reducing drying efficiency. To address these issues, a closed-loop heat pump dryer is proposed as a solution. Utility Model Content

[0004] To address the aforementioned technical problems, this utility model provides a closed-loop heat pump dryer, which solves the problems of high energy consumption, direct discharge of hot and humid air during dehumidification leading to heat waste, which not only increases energy consumption but may also prolong the production cycle and affect overall work efficiency. Furthermore, the condenser of the heat pump dryer is prone to frosting, which affects the efficiency of heat exchange and requires frequent defrosting, further reducing the drying efficiency.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a closed-loop heat pump dryer, including a drying chamber, a compressor, dual evaporators, zoned condensers, a waste heat recovery device, a fan, a humidity sensor, an airflow guide plate, and a control unit;

[0006] The dual evaporator consists of a main evaporator and an auxiliary evaporator connected in series. The main evaporator is connected to the return air duct of the drying chamber, and the auxiliary evaporator is connected to the fresh air inlet.

[0007] The partitioned condenser is divided into a high-temperature zone and a low-temperature zone, and the heat distribution path is switched by a three-way valve.

[0008] The waste heat recovery device transfers the waste heat from the condenser to the fresh air duct through heat exchange tubes.

[0009] The fan is used to drive the airflow to circulate between the drying chamber, the dual evaporators, and the zoned condensers;

[0010] The humidity sensor is installed inside the drying chamber to monitor the humidity inside the drying chamber in real time.

[0011] The air flow guide plate is arranged inside the drying chamber and is used for guiding the flow direction of the air flow.

[0012] The control unit is electrically connected with the compressor, the three-way valve, the fan and the humidity sensor respectively, and the operation frequency of the compressor, the switching of the three-way valve and the rotating speed of the fan are controlled according to the humidity information fed back by the humidity sensor.

[0013] Preferably, the main evaporator and the auxiliary evaporator are both finned evaporators, and the fin spacing of the auxiliary evaporator is greater than the fin spacing of the main evaporator.

[0014] Preferably, the heat exchange pipe arrangement density in the high-temperature zone is different from that in the low-temperature zone, and the heat exchange pipe arrangement density in the high-temperature zone is greater than that in the low-temperature zone.

[0015] Preferably, the heat exchange pipe of the waste heat recovery device is in a spiral structure to increase the heat exchange area.

[0016] Preferably, the fan is an axial flow fan, and a flow guide cover is arranged at the air outlet of the fan to uniformly blow air.

[0017] Preferably, the air flow guide plate is in an angle-adjustable structure, and the angle adjustment is realized by an electric push rod or a stepping motor.

[0018] Preferably, the inner wall of the drying chamber is provided with a heat preservation layer, and the heat preservation layer is made of polyurethane foam material.

[0019] Compared with the prior art, the utility model has the advantages that:

[0020] 1. The utility model discloses a double evaporator series connection design (main evaporator and auxiliary evaporator) is arranged, the main evaporator handles return air humidity, and the auxiliary evaporator prehandles fresh air, improves dehumidification efficiency, and through this division of labor, two evaporators can exert respective advantages, improve the overall dehumidification effect of the system, and the return air humidity is higher, and the humidity of fresh air is relatively lower, and separate treatment can avoid that the main evaporator is burdened by too much moisture, and the dehumidification efficiency is kept higher.

[0021] 2. The utility model discloses that the condenser is divided into high-temperature zone (drying heating) and low-temperature zone (preheating fresh air), and through valve switching heat distribution, can adjust heat distribution according to demand, so that the low-temperature zone does not overcool, avoids frost formation on the surface of the condenser, thereby reduces frosting phenomenon, optimizes the heat exchange efficiency of the condenser, and ensures the overall energy efficiency of the system.

[0022] 3. The utility model discloses a waste heat recovery device is additionally arranged, and the waste heat after drying is used for preheating fresh air, not only fully utilizes these originally discharged heat, but also can significantly reduce energy consumption, improves the overall energy utilization efficiency, which can effectively save energy cost and improve economic benefit. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model;

[0024] Figure 2 This is a schematic diagram of the internal structure of this utility model;

[0025] Figure 3 This is a schematic diagram of the internal structure of this utility model from another perspective;

[0026] Figure 4 This diagram shows the connection relationships between the various components of the dryer of this utility model.

[0027] The numbers on the map are:

[0028] 1. Drying chamber; 2. Compressor; 3. Dual evaporators; 301. Main evaporator; 302. Auxiliary evaporator; 4. Zoned condenser; 401. High-temperature zone; 402. Low-temperature zone; 5. Waste heat recovery device; 6. Fan; 7. Humidity sensor; 8. Airflow guide plate; 9. Control unit; 10. Three-way valve. Detailed Implementation

[0029] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0030] Reference Figures 1-4 As shown, a closed-loop heat pump dryer includes a drying chamber 1, a compressor 2, a dual evaporator 3, a zoned condenser 4, a waste heat recovery device 5, a fan 6, a humidity sensor 7, an airflow guide plate 8, and a control unit 9.

[0031] The dual evaporator 3 consists of a main evaporator 301 and an auxiliary evaporator 302 connected in series. The main evaporator 301 is connected to the return air duct of the drying chamber 1, and the auxiliary evaporator 302 is connected to the fresh air inlet. This design can handle the return air and fresh air of the drying chamber 1 at the same time, which improves the heat exchange efficiency and energy utilization.

[0032] The zoned condenser 4 is divided into a high-temperature zone 401 and a low-temperature zone 402, and the heat distribution path is switched by a three-way valve 10.

[0033] Waste heat recovery device 5 transfers the waste heat from the condenser to the fresh air duct through heat exchange tubes;

[0034] Fan 6 is used to drive airflow to circulate between drying chamber 1, dual evaporators 3, and zoned condensers 4;

[0035] Humidity sensor 7 is installed inside drying chamber 1 to monitor the humidity inside drying chamber 1 in real time;

[0036] The air flow guide plate 8 is arranged inside the drying chamber 1 and is used to guide the flow direction of the air flow;

[0037] Specifically, the control unit 9 is electrically connected with the compressor 2, the three-way valve 10, the fan 6 and the humidity sensor 7, respectively, and controls the operating frequency of the compressor 2, the switching of the three-way valve 10 and the rotating speed of the fan 6 according to the humidity information fed back by the humidity sensor 7. The control unit 9 can dynamically adjust the operating frequency of the compressor 2, the switching of the three-way valve 10 and the rotating speed of the fan 6 according to the information fed back by the humidity sensor 7, so as to realize intelligent control.

[0038] Specifically, the main evaporator 301 and the auxiliary evaporator 302 are both finned evaporators, and the fin spacing of the auxiliary evaporator 302 is greater than that of the main evaporator 301. The fin spacing of the auxiliary evaporator 302 is greater than that of the main evaporator 301, which helps to reduce the resistance on the fresh air side while maintaining efficient heat exchange.

[0039] Specifically, the heat exchange pipe arrangement densities in the high-temperature zone 401 and the low-temperature zone 402 are different. The heat exchange pipe arrangement density in the high-temperature zone 401 is greater than that in the low-temperature zone 402. The heat exchange pipe arrangement density in the high-temperature zone 401 is greater, which helps to more efficiently transfer heat to hot air, while the low-temperature zone 402 is relatively loose to adapt to different heat demands.

[0040] Specifically, the heat exchange pipe of the waste heat recovery device 5 is in a spiral structure to increase the heat exchange area and improve the waste heat recovery efficiency, which helps to save energy and reduce consumption.

[0041] Specifically, the fan 6 is an axial flow fan, and the fan 6 is provided with a flow guide cover at the air outlet for uniform air outlet, which helps to improve the drying efficiency.

[0042] Specifically, the air flow guide plate 8 is an adjustable angle structure, and the angle adjustment is realized by an electric push rod or a stepping motor. The air flow guide plate 8 can be flexibly adjusted according to the drying requirements to improve the drying uniformity.

[0043] Specifically, the inner wall of the drying chamber 1 is provided with a thermal insulation layer, and the thermal insulation layer is made of polyurethane foam material. The thermal insulation layer has good thermal insulation performance, which helps to reduce energy loss and improve drying efficiency.

[0044] Working principle: before starting, the control unit 9 selects the drying process curve according to the material characteristics and sets the parameters, the outside fresh air passes through the auxiliary evaporator 302, the return air of the drying chamber 1 passes through the main evaporator 301, after the series connection of the two, the gas enters the variable frequency compressor 2 to increase the temperature and pressure, the high temperature and high pressure gas enters the partition condenser 4, the three-way valve 10 distributes the heat to the high temperature area 401 and the low temperature area 402 according to the requirement to heat the hot air, the axial flow fan 6 drives the hot air to blow to the material uniformly through the airflow guide plate 8, the humidity sensor 7 monitors the humidity in real time and feeds back to the control unit 9, the control unit 9 dynamically adjusts the equipment operation, at the same time, the waste heat recovery device 5 preheats the fresh air by using the waste heat after drying, when the humidity of the dried material reaches the standard, the equipment stops running, and the drying is completed.

[0045] The basic principle, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection required by the present application is defined by the appended claims and their equivalents.

Claims

1. A closed loop heat pump dryer characterised in that: It comprises a drying chamber (1), a compressor (2), a double evaporator (3), a partitioned condenser (4), a waste heat recovery device (5), a fan (6), a humidity sensor (7), an air flow guide plate (8) and a control unit (9). The double evaporator (3) is composed of a main evaporator (301) and an auxiliary evaporator (302) in series, the main evaporator (301) is connected to the return air duct of the drying chamber (1), and the auxiliary evaporator (302) is connected to the fresh air inlet. The partitioned condenser (4) is divided into a high-temperature zone (401) and a low-temperature zone (402), and the heat distribution path is switched by a three-way valve (10). The waste heat recovery device (5) conducts the condenser waste heat to the fresh air duct through heat exchange pipes. The fan (6) is used to drive the air flow to circulate between the drying chamber (1), the double evaporator (3) and the partitioned condenser (4). The humidity sensor (7) is arranged in the drying chamber (1) to monitor the humidity in the drying chamber (1) in real time. The air flow guide plate (8) is arranged inside the drying chamber (1) to guide the flow direction of the air flow. The control unit (9) is electrically connected with the compressor (2), the three-way valve (10), the fan (6) and the humidity sensor (7), and controls the operating frequency of the compressor (2), the switching of the three-way valve (10) and the rotating speed of the fan (6) according to the humidity information fed back by the humidity sensor (7).

2. A closed loop heat pump dryer as claimed in claim 1, wherein: The main evaporator (301) and the auxiliary evaporator (302) are both finned evaporators, and the fin pitch of the auxiliary evaporator (302) is greater than that of the main evaporator (301).

3. A closed loop heat pump dryer as claimed in claim 2, wherein: The heat exchange pipes in the high-temperature zone (401) and the low-temperature zone (402) have different arrangement densities, and the arrangement density of the heat exchange pipes in the high-temperature zone (401) is greater than that in the low-temperature zone (402).

4. A closed loop heat pump dryer as claimed in claim 3, wherein: The heat exchange pipes of the waste heat recovery device (5) are in spiral structure to increase the heat exchange area.

5. A closed loop heat pump dryer as claimed in claim 4, wherein: The fan (6) is an axial flow fan, and the outlet of the fan (6) is provided with a flow guide cover for uniform air outlet.

6. A closed loop heat pump dryer as claimed in claim 5, wherein: The air flow guide plate (8) is an adjustable angle structure, and the angle adjustment is realized by an electric push rod or a stepping motor.

7. A closed loop heat pump dryer as claimed in claim 6, wherein: The inner wall of the drying chamber (1) is provided with a thermal insulation layer, and the thermal insulation layer is made of polyurethane foam material.

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