CN215063281U

CN215063281U - Well low temperature air source heat pump drying-machine device

Info

Publication number: CN215063281U
Application number: CN202120586965.9U
Authority: CN
Inventors: 任志峰; 王彩烈; 邵长胜; 刘建成
Original assignee: Shandong Ourfuture Energy Technology Co ltd
Current assignee: Shandong Ourfuture Energy Technology Co ltd
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2021-12-07
Anticipated expiration: 2031-03-23

Abstract

The utility model discloses a medium and low temperature air source heat pump dryer device, which comprises a drying room, wherein the drying room is provided with a preheating mechanism and a drying mechanism; the preheating mechanism includes: the device comprises a first combustion chamber, an isolation pipeline, a water inlet pipe and a heat dissipation structure; the first combustion chamber is fixed in the outside in stoving room, the both ends of keeping apart the inside that the pipeline is fixed in first combustion chamber, the inlet tube runs through in the middle part of keeping apart the pipeline, heat radiation structure settles in the inside in stoving room, stoving mechanism includes: the system comprises an indoor evaporator, a four-way valve, a first pipeline, a compressor, a second pipeline, a separator, a preheating structure, a condensation structure, a control structure and an air supply structure; the beneficial effects of the utility model are that, reasonable in design, the cost is lower, and convenient to use has changed current drying-machine and can only be applied to the current situation that is higher than ambient temperature, satisfies the operation requirement, has improved the practicality.

Description

Well low temperature air source heat pump drying-machine device

Technical Field

The utility model relates to a drying-machine technical field, especially a well low temperature air source heat pump drying-machine device.

Background

Dryers can be divided into industrial dryers, also called drying plants or dryers, and domestic dryers, which are one type of washing machine, are generally used to remove moisture from garments and other textiles after dehydration in a water wash.

The dryer has several modes, such as belt drying, roller drying, box drying, tower drying and the like; the heat source is coal, electricity, gas and the like; the materials are in a hot air flow type, a radiation type and the like in the drying process, the hot air roller drying is that hot air flows forwards from the tail part and is fully contacted with the materials, and the heat transfer quantity is fully utilized through heat conduction, convection and radiation; heat energy is directly transferred to the materials, so that moisture of the materials is continuously evaporated in the cylinder, and a large amount of moisture and wet air flow is extracted by an air inducing device at the feeding port, so that secondary pollution caused by dust discharge is prevented; the materials are pushed to move through internal spiral stirring, sweeping and shoveling plates, and the whole drying process is completed; and the countercurrent conduction dehumidification is adopted, so that repeated drying procedures are avoided.

However, when the required drying temperature of the existing dryer is lower than the ambient temperature or close to the ambient temperature, the dehumidifier cannot well meet the requirements, and the existing dryer can only be applied to the current situation that the temperature is higher than the ambient temperature.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the above problem, design a well low temperature air source heat pump drying-machine device, solved current drying-machine when the stoving temperature that requires is less than ambient temperature or is close with ambient temperature, the dehumidifier can not be fine the requirement of satisfying, and current drying-machine can only be applied to the current situation that is higher than ambient temperature.

Realize above-mentioned purpose the utility model discloses a technical scheme does: a medium-low temperature air source heat pump drying machine device comprises a drying room, wherein a preheating mechanism and a drying mechanism are installed in the drying room;

the preheating mechanism includes: the device comprises a first combustion chamber, an isolation pipeline, a water inlet pipe and a heat dissipation structure;

the first combustion chamber is fixed on the outer side of the drying room, two ends of the isolation pipeline are fixed inside the first combustion chamber, the water inlet pipe penetrates through the middle part of the isolation pipeline, and the heat dissipation structure is arranged inside the drying room.

The drying mechanism includes: the system comprises an indoor evaporator, a four-way valve, a first pipeline, a compressor, a second pipeline, a separator, a preheating structure, a condensation structure, a control structure and an air supply structure;

the indoor evaporator is arranged in the drying room, the four-way valve is communicated with an air outlet pipe of the indoor evaporator, the first pipeline is communicated with one end of the four-way valve, the compressor is arranged in the drying room, an air inlet end of the compressor is communicated with the first pipeline, one end of the second pipeline is communicated with one end of the compressor, one end of the separator is connected to the other end of the second pipeline, the other end of the separator is communicated with the four-way valve, the condensation structure is arranged in the drying room and communicated with the four-way valve, the control structure is arranged in the drying room and communicated with the first pipeline, and the air supply structure is arranged in the drying room and outside the drying room.

Preferably, the heat dissipation structure includes: the second combustion chamber, the water containing pot, the shell, a plurality of heat conducting fins, two fans, a plurality of electric push rods and two plugging doors;

the second combustion chamber is arranged in the drying room, the water containing pot is fixed at the upper end of the combustion chamber, the shell is fixed at the upper end of the water containing pot, the heat conducting fins penetrate through the lower wall surface of the shell, the two fans are arranged on the wall surface of the shell respectively, the electric push rods are embedded in the wall surface of the shell respectively, the two plugging doors are movably arranged in the wall surface of the shell, and two ends of each plugging door are fixed at the telescopic ends of the two electric push rods respectively.

Preferably, the condensation structure includes: the outdoor condenser comprises a third pipeline, an indoor condenser, a first one-way valve, a fourth pipeline and an outdoor condenser;

one end of the third pipeline is communicated with the four-way valve and the second pipeline, the indoor condenser is arranged in the drying room and is communicated with the other end of the third pipeline, the first one-way valve is arranged on the third pipeline, one end of the fourth pipeline is communicated with the third pipeline, the outdoor condenser is arranged on the outer side of the drying room, and the outdoor condenser is communicated with the other end of the fourth pipeline.

Preferably, the control structure includes: the drying electromagnetic valve, the temperature control electromagnetic valve, the fifth pipeline, the sixth pipeline and the filtering part;

the drying electromagnetic valve is arranged at the outlet end of the indoor condenser, the temperature control electromagnetic valve is arranged at the outlet end of the outdoor condenser, the fifth pipeline is communicated with the outlet end of the outdoor condenser and the outlet end of the indoor condenser, the middle part of the sixth pipeline is communicated with the fifth pipeline, and the filtering part is arranged inside the dryer and communicated with the sixth pipeline.

Preferably, the air blowing structure includes: an indoor circulating fan, an exhaust fan and an outdoor evaporating fan;

the indoor circulating fan is arranged inside the drying room, the exhaust fan is arranged inside the drying room, and the outdoor evaporation fan is arranged outside the drying room.

Preferably, a defrosting portion is further installed on the fourth duct, and the defrosting portion includes: the connecting pipe, the two third one-way valves and the defrosting electromagnetic valve;

the connecting pipe is communicated with the fourth pipeline, the two third one-way valves are respectively arranged on the connecting pipe and the fourth pipeline, and the defrosting electromagnetic valve is arranged on the connecting pipe.

Preferably, the filter part includes: the liquid storage device, the third needle valve, the filter, the seventh pipeline, the water return pipe and the switch component are arranged on the water storage device;

the water inlet end of the liquid storage device is communicated with one end of a sixth pipeline, the third needle valve is arranged at the water outlet end of the liquid storage device, the filter is communicated with the water outlet end of the liquid storage device, one end of the seventh pipeline is communicated with the water outlet end of the filter and the water inlet end of the indoor evaporator, the seventh pipeline is communicated with the sixth pipeline, the water return pipe is communicated with the seventh pipeline, and the switch assembly is arranged on the seventh pipeline.

Preferably, the switch assembly includes: the thermostatic expansion valve, the two second one-way valves and the main path electromagnetic valve;

the thermostatic expansion valve is arranged on a seventh pipeline, the two second one-way valves are arranged on a sixth pipeline, and the main solenoid valve is arranged on the seventh pipeline.

Preferably, the first pipeline is provided with a first needle valve.

Preferably, the second pipeline is provided with a second needle valve, and the second pipeline is provided with a pressure switch.

Utilize the utility model discloses a well low temperature air source heat pump drying-machine device of technical scheme preparation, reasonable in design, the cost is lower, high durability and convenient use, the current situation that is higher than ambient temperature can only be applied to the drying-machine that has changed now, satisfy the operation requirement, improved the practicality effectually solved among the background art when the stoving temperature that requires is less than ambient temperature or is close with ambient temperature, the dehumidifier can not be fine the sufficient requirement of satisfaction, and current drying-machine can only be applied to the current situation that is higher than ambient temperature.

Drawings

Fig. 1 is a schematic view of a top-down sectional structure of a medium-low temperature air source heat pump dryer device.

Fig. 2 is a left-side sectional structure schematic diagram of a first combustion chamber of a middle-low temperature air source heat pump dryer device.

Fig. 3 is a schematic diagram of a second combustion chamber right-side view cross-sectional structure of a middle and low temperature air source heat pump dryer device.

Fig. 4 is a structural schematic diagram of a second combustion chamber of the middle and low temperature air source heat pump dryer device in a right view.

Fig. 5 is a schematic diagram of a partial enlarged structure of an electric push rod of the middle and low temperature air source heat pump dryer device shown in fig. 1 according to the present invention.

Fig. 6 is a schematic diagram of a third one-way valve of a middle and low temperature air source heat pump dryer apparatus according to the present invention 1.

In the figure: 1. a drying room; 2. an indoor evaporator; 3. a four-way valve; 4. a first conduit; 5. a compressor; 6. a second conduit; 7. a separator; 8. a third pipeline; 9. an indoor condenser; 10. a first check valve; 11. a fourth conduit; 12. an outdoor condenser; 13. Drying the electromagnetic valve; 14. a temperature control electromagnetic valve; 15. a fifth pipeline; 16. a sixth pipeline; 17. an indoor circulating fan; 18. an exhaust fan; 19. an outdoor evaporation fan; 20. a connecting pipe; 21. a third check valve; 22. a defrosting electromagnetic valve; 23. a reservoir; 24. a third needle valve; 25. a filter; 26. a seventh pipe; 27. a water return pipe; 28. a thermostatic expansion valve; 29. a second one-way valve; 30. a main path electromagnetic valve; 31. a first needle valve; 32. A second needle valve; 33. a pressure switch; 34. a first combustion chamber; 35. isolating the pipeline; 36. A water inlet pipe; 37. a second combustion chamber; 38. a water containing pot; 39. a housing; 40. a heat conductive sheet; 41. a fan; 42. an electric push rod; 43. and (6) sealing the door.

Detailed Description

Example (b): a medium-low temperature air source heat pump drying machine device comprises a drying room 1, wherein a preheating mechanism and a drying mechanism are installed in the drying room 1;

referring to fig. 1-6, in an embodiment, the preheating mechanism includes: a first combustion chamber 34, an isolation pipe 35, a water inlet pipe 36 and a heat dissipation structure; the connection relationship is as follows:

the first combustion chamber 34 is fixed at the outer side of the drying room 1, two ends of the isolation pipeline 35 are fixed inside the first combustion chamber 34, the water inlet pipe 36 penetrates through the middle part of the isolation pipeline 35, and the heat dissipation structure is arranged inside the drying room 1.

In a specific implementation process, it should be noted that the drying mechanism includes: the system comprises an indoor evaporator 2, a four-way valve 3, a first pipeline 4, a compressor 5, a second pipeline 6, a separator 7, a preheating structure, a condensing structure, a control structure and an air supply structure; the connection relationship is as follows:

the indoor evaporator 2 is arranged inside the drying room 1, the four-way valve 3 is communicated with an air outlet pipe of the indoor evaporator 2, the first pipeline 4 is communicated with one end of the four-way valve 3, the compressor 5 is arranged inside the drying room 1, an air inlet end of the compressor is communicated with the first pipeline 4, one end of the second pipeline 6 is communicated with one end of the compressor 5, one end of the separator 7 is connected with the other end of the second pipeline 6, the other end of the separator 7 is communicated with the four-way valve 3, the condensation structure is arranged inside the drying room 1 and communicated with the four-way valve, the control structure is arranged inside the drying room 1 and communicated with the first pipeline 4, and the air supply structure is arranged inside and outside the drying room 1.

In a specific implementation process, it should be noted that the heat dissipation structure includes: a second combustion chamber 37, a water containing pot 38, a shell 39, a plurality of heat conducting fins 40, two fans 41, a plurality of electric push rods 42 and two plugging doors 43; the connection relationship is as follows:

the second combustion chamber 37 is disposed inside the drying room 1, the water containing pot 38 is fixed to the upper end of the combustion chamber, the casing 39 is fixed to the upper end of the water containing pot 38, the plurality of heat conducting fins 40 penetrate through the lower wall surface of the casing 39, the two fans 41 are disposed on the wall surface of the casing 39 respectively, the plurality of electric push rods 42 are embedded inside the wall surface of the casing 39 respectively, the two blocking doors 43 are movably disposed inside the wall surface of the casing 39, and two ends of the two blocking doors are fixed to the telescopic ends of the two electric push rods 42 respectively.

In a specific implementation process, it should be noted that the condensation structure includes: a third pipe 8, an indoor condenser 9, a first check valve 10, a fourth pipe 11, and an outdoor condenser 12; the connection relationship is as follows:

one end of the third pipeline 8 is communicated with the four-way valve 3 and the second pipeline 6, the indoor condenser 9 is disposed inside the drying room 1 and is communicated with the other end of the third pipeline 8, the first one-way valve 10 is disposed on the third pipeline 8, one end of the fourth pipeline 11 is communicated with the third pipeline 8, the outdoor condenser 12 is disposed outside the drying chamber, and the outdoor condenser 12 is communicated with the other end of the fourth pipeline 11.

In a specific implementation process, it should be noted that the control structure includes: a drying electromagnetic valve 13, a temperature control electromagnetic valve 14, a fifth pipeline 15, a sixth pipeline 16 and a filtering part; the connection relationship is as follows:

the drying solenoid valve 13 is disposed at an outlet end of the indoor condenser 9, the temperature control solenoid valve 14 is disposed at an outlet end of the outdoor condenser 12, the fifth pipeline 15 is communicated with the outlet end of the outdoor condenser 12 and the outlet end of the indoor condenser 9, a middle portion of the sixth pipeline 16 is communicated with the fifth pipeline 15, and the filter portion is disposed inside the dryer and is communicated with the sixth pipeline 16.

In a specific implementation process, it should be noted that the air supply structure includes: an indoor circulating fan 17, an exhaust fan 18, and an outdoor evaporating fan 19; the connection relationship is as follows:

the indoor circulating fan 17 is disposed inside the drying room 1, the exhaust fan 18 is disposed inside the drying room 1, and the outdoor evaporating fan 19 is disposed outside the drying room 1.

In a specific implementation process, it should be noted that a defrosting portion is further installed on the fourth pipeline 11, and the defrosting portion includes: a connecting pipe 20, two third check valves 21 and a defrosting electromagnetic valve 22; the connection relationship is as follows:

the connecting pipe 20 is communicated with the fourth pipeline 11, the two third check valves 21 are respectively disposed on the connecting pipe 20 and the fourth pipeline 11, and the defrosting solenoid valve 22 is disposed on the connecting pipe 20.

In a specific implementation process, it should be noted that the filter unit includes: a liquid storage device 23, a third needle valve 24, a filter 25, a seventh pipeline 26, a water return pipe 27 and a switch component; the connection relationship is as follows:

the water inlet end of the liquid storage device 23 is communicated with one end of the sixth pipeline 16, the third needle valve 24 is disposed on the water outlet end of the liquid storage device 23, the filter 25 is communicated with the water outlet end of the liquid storage device 23, one end of the seventh pipeline 26 is communicated with the water outlet end of the filter 25 and the water inlet end of the indoor evaporator 2, the seventh pipeline 26 is communicated with the sixth pipeline 16, the water return pipe 27 is communicated with the seventh pipeline 26, and the switch assembly is disposed on the seventh pipeline 26.

In a specific implementation process, it should be noted that the switch assembly includes: a thermostatic expansion valve 28, two second check valves 29 and a main solenoid valve 30; the connection relationship is as follows:

the thermostatic expansion valve 28 is disposed on the seventh pipe 26, two of the second check valves 29 are disposed on the sixth pipe 16, and the main solenoid valve 30 is disposed on the seventh pipe 26.

From the above general situation it follows that: when the device is used, firstly, when the drying temperature required in the drying room 1 is lower than the outdoor environment temperature, the indoor evaporator 2 and the outdoor condenser 12 start to work, the low-pressure gas coming out of the indoor evaporator 2 enters the compressor 5 through the first pipeline 4, is compressed into high-temperature high-pressure gas, is discharged through the second pipeline 6, at the moment, the first one-way valve 10 on the third pipeline 8 is in a closed state, then enters the outdoor condenser 12 through the third pipeline 8 and the fourth pipeline 11, the defrosting electromagnetic valve 22 on the connecting pipe 20 is used for controlling defrosting of the outdoor condenser 12, then the high-temperature gas enters the condenser to release heat, so that heat exchange is realized, then the gas flow enters the sixth pipeline 16 through the fifth pipeline 15, the drying electromagnetic valve 13 on the fifth pipeline 15 is used for realizing automatic drying, and the temperature control electromagnetic valve 14 is used for realizing automatic temperature control, then the second check valve 29 is opened, the water in the air flow enters the liquid reservoir 23, the third needle valve 24 is used for adjusting or cutting off the liquid flowing out from the liquid reservoir 23, the liquid is filtered by the filter 25, then the main electromagnetic valve 30 is opened, because one end of the seventh pipeline 26 is connected to the water inlet end of the indoor evaporator 2, circulation is realized, meanwhile, the air flow coming out from the compressor 5 contains the liquid, the liquid is conveyed into the separator 7 through the second pipeline 6 for separation, after the liquid is separated out, the air flow enters the liquid reservoir 23 through the sixth pipeline 16 through the return pipe 27, when the temperature required by the drying room 1 is higher than the outdoor environment temperature, firstly, the water inlet pipe 36 is connected into the water supply pipe, then the first combustion chamber 34 combusts the fuel, the fuel heats the inside of the first combustion chamber 34 outside the isolation pipeline 35, thereby heating the water inlet pipe 36, in the process that the water supply enters the water containing pot 38 through the water inlet pipe 36, the first combustion chamber 34 primarily heats tap water, then the second combustion chamber 37 combusts to heat the water containing pot 38, the hot water is guided out under the action of the heat conducting fins 40, then the electric push rod 42 begins to extend to drive the blocking door 43 to open, the fan 41 begins to rotate to blow hot air inside the shell 39 into the drying room 1, the temperature rising speed of the drying room 1 is increased, the indoor evaporator 2 and the indoor condenser 9 are opened to work, during the working process, the first one-way valve 10 on the third pipeline 8 is opened, air flow passes through the third pipeline 8 and enters the indoor condenser 9, then enters the liquid storage device 23 through the fifth pipeline 15 and the sixth pipeline 16, after being filtered by the filter 25, enters the indoor evaporator 2 through the seventh pipeline 26 to realize circulation, the exhaust fan 18 is used for exhausting air, the indoor circulating fan 17 is used for realizing indoor air circulation and radiating heat to the indoor evaporator 2, the outdoor evaporation fan 19 is used for adjusting the outdoor temperature and for cooling the outdoor condenser 12.

Preferably, the first tube 4 is further provided with a first needle valve 31.

Preferably, the second pipe 6 is provided with a second needle valve 32, and the second pipe 6 is provided with a pressure switch 33.

Above-mentioned technical scheme has only embodied the utility model discloses technical scheme's preferred technical scheme, some changes that this technical field's technical personnel probably made to some parts wherein have all embodied the utility model discloses a principle belongs to within the protection scope of the utility model.

Claims

1. A medium-low temperature air source heat pump dryer device comprises a drying room (1), and is characterized in that a preheating mechanism and a drying mechanism are installed in the drying room (1);

the preheating mechanism includes: the device comprises a first combustion chamber (34), an isolation pipeline (35), a water inlet pipe (36) and a heat dissipation structure;

the first combustion chamber (34) is fixed at the outer side of the drying room (1), two ends of the isolation pipeline (35) are fixed in the first combustion chamber (34), the water inlet pipe (36) penetrates through the middle part of the isolation pipeline (35), and the heat dissipation structure is arranged in the drying room (1);

the drying mechanism includes: the system comprises an indoor evaporator (2), a four-way valve (3), a first pipeline (4), a compressor (5), a second pipeline (6), a separator (7), a preheating structure, a condensing structure, a control structure and an air supply structure;

the indoor evaporator (2) is arranged inside the drying room (1), the four-way valve (3) is communicated with an air outlet pipe of the indoor evaporator (2), the first pipeline (4) is communicated with one end of a four-way valve (3), the compressor (5) is arranged inside the drying room (1), and the air inlet end is communicated with the first pipeline (4), one end of the second pipeline (6) is communicated with one end of the compressor (5), one end of the separator (7) is connected with the other end of the second pipeline (6), the other end of the separator (7) is communicated with the four-way valve (3), the condensing structure is arranged in the drying room (1) and is communicated with the four-way valve, the control structure is arranged in the drying room (1) and communicated with the first pipeline (4), and the air supply structure is arranged in the drying room (1) and on the outer side of the drying room.

2. The medium and low temperature air source heat pump dryer apparatus of claim 1, wherein the heat dissipation structure comprises: a second combustion chamber (37), a water containing pot (38), a shell (39), a plurality of heat conducting fins (40), two fans (41), a plurality of electric push rods (42) and two plugging doors (43);

the second combustion chamber (37) is arranged in the drying room (1), the water containing pot (38) is fixed at the upper end of the combustion chamber, the shell (39) is fixed at the upper end of the water containing pot (38), the heat conducting fins (40) penetrate through the lower wall surface of the shell (39), the two fans (41) are respectively arranged on the wall surface of the shell (39), the electric push rods (42) are respectively embedded in the wall surface of the shell (39), the two blocking doors (43) are movably arranged in the wall surface of the shell (39), and two ends of each blocking door are respectively fixed on the telescopic ends of the two electric push rods (42).

3. The medium and low temperature air source heat pump dryer apparatus of claim 1, wherein the condensing structure comprises: a third pipeline (8), an indoor condenser (9), a first one-way valve (10), a fourth pipeline (11) and an outdoor condenser (12);

one end of the third pipeline (8) is communicated with the four-way valve (3) and the second pipeline (6), the indoor condenser (9) is arranged inside the drying room (1) and communicated with the other end of the third pipeline (8), the first one-way valve (10) is arranged on the third pipeline (8), one end of the fourth pipeline (11) is communicated with the third pipeline (8), the outdoor condenser (12) is arranged on the outer side of the drying room, and the outdoor condenser (12) is communicated with the other end of the fourth pipeline (11).

4. The medium and low temperature air source heat pump dryer apparatus of claim 1, wherein the control structure comprises: a drying electromagnetic valve (13), a temperature control electromagnetic valve (14), a fifth pipeline (15), a sixth pipeline (16) and a filtering part;

the drying electromagnetic valve (13) is arranged at the outlet end of the indoor condenser (9), the temperature control electromagnetic valve (14) is arranged at the outlet end of the outdoor condenser (12), the fifth pipeline (15) is communicated with the outlet end of the outdoor condenser (12) and the outlet end of the indoor condenser (9), the middle part of the sixth pipeline (16) is communicated with the fifth pipeline (15), and the filtering part is arranged inside the dryer and is communicated with the sixth pipeline (16).

5. The medium and low temperature air source heat pump dryer apparatus of claim 1, wherein the air supply structure comprises: an indoor circulating fan (17), an exhaust fan (18) and an outdoor evaporating fan (19);

the indoor circulating fan (17) is arranged inside the drying room (1), the exhaust fan (18) is arranged inside the drying room (1), and the outdoor evaporating fan (19) is arranged outside the drying room (1).

6. The medium and low temperature air source heat pump dryer device according to claim 3, wherein the fourth duct (11) is further installed with a defrosting part, and the defrosting part comprises: a connecting pipe (20), two third one-way valves (21) and a defrosting electromagnetic valve (22);

the connecting pipe (20) is communicated with the fourth pipeline (11), the two third one-way valves (21) are respectively arranged on the connecting pipe (20) and the fourth pipeline (11), and the defrosting electromagnetic valve (22) is arranged on the connecting pipe (20).

7. The medium and low temperature air source heat pump dryer apparatus of claim 4, wherein the filter section comprises: the device comprises a liquid storage device (23), a third needle valve (24), a filter (25), a seventh pipeline (26), a water return pipe (27) and a switch component;

the water inlet end of the liquid storage device (23) is communicated with one end of a sixth pipeline (16), the third needle valve (24) is arranged at the water outlet end of the liquid storage device (23), the filter (25) is communicated with the water outlet end of the liquid storage device (23), one end of the seventh pipeline (26) is communicated with the water outlet end of the filter (25) and the water inlet end of the indoor evaporator (2), the seventh pipeline (26) is communicated with the sixth pipeline (16), the water return pipe (27) is communicated with the seventh pipeline (26), and the switch assembly is arranged on the seventh pipeline (26).

8. The medium and low temperature air source heat pump dryer apparatus of claim 7 wherein the switch assembly comprises: a thermostatic expansion valve (28), two second one-way valves (29) and a main solenoid valve (30);

the thermostatic expansion valve (28) is arranged on a seventh pipeline (26), the two second one-way valves (29) are arranged on a sixth pipeline (16), and the main circuit solenoid valve (30) is arranged on the seventh pipeline (26).

9. The medium and low temperature air source heat pump dryer device according to claim 1, characterized in that the first duct (4) is mounted with a first needle valve (31).

10. The medium and low temperature air source heat pump dryer device according to claim 1, characterized in that the second duct (6) is installed with a second needle valve (32), and the second duct (6) is installed with a pressure switch (33).