CN108317850B

CN108317850B - Heat pump drying device

Info

Publication number: CN108317850B
Application number: CN201810245509.0A
Authority: CN
Inventors: 黄玉优; 李欣; 叶强蔚
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2018-03-23
Filing date: 2018-03-23
Publication date: 2023-03-10
Anticipated expiration: 2038-03-23
Also published as: CN108317850A

Abstract

The application provides a heat pump drying device. The heat pump drying device comprises an evaporation chamber, a condensation chamber, an air supply chamber and an integral air valve. Wherein, the evaporation chamber is internally provided with an evaporator, and the condensation chamber is internally provided with a condenser. The evaporation chamber is communicated with the external environment through a first air door, and is communicated with the condensation chamber through a second air door. The air supply chamber is communicated with the condensing chamber through a third air door and is communicated with the evaporating chamber through a fourth air door. The integral air valve piece is movably arranged on the evaporation chamber and the air supply chamber and comprises: a first state of blocking the second damper, opening the first damper and the third damper; and a second state in which the first damper and the third damper are blocked and the second damper is opened. By adopting the technical scheme of the invention, the adjustment of different modes of the heat pump drying device can be realized only by the movable integral air valve piece without arranging a complicated air duct and a plurality of control air valve assemblies, and the heat pump drying device is convenient and quick.

Description

Heat pump drying device

Technical Field

The invention relates to the technical field of air conditioners, in particular to a heat pump drying device.

Background

When the closed heat pump drying device reaches a stable working temperature, the temperature is not necessarily just the proper temperature required by material drying, and the circulating air outlet temperature needs to be accurately controlled. Because the cold energy emitted by the evaporator is not discharged into the external environment of the integral unit but transmitted to the closed circulating air, the unit starting speed of the closed heat pump drying device is too slow, and the slow heating speed of the circulating air is not beneficial to the quick starting of industrial production.

Aiming at the two defects, the basic closed heat pump drying device has a plurality of improved forms, and the device is mainly provided with an auxiliary condenser or an auxiliary evaporator to realize quick start and temperature rise, or adopts an air duct design with mixed return air and outlet air in a certain proportion, or adopts a frequency conversion control technology to realize accurate temperature control.

The addition of an auxiliary heat exchanger and other parts of the refrigeration system requires the corresponding addition of some system control parts, which results in complex structure, poor control reliability and the like of the refrigeration system. If the conversion between the closed air channel and the open air channel is realized through the air channel conversion, the refrigeration system does not need to be modified, and the system is simple and reliable to control; the air duct and the control air valve have no fault which affects the reliability of the refrigerating system, and the maintenance is simpler and more convenient. For example, CN107543333 is an application case of air duct conversion.

However, the air duct change and the increase of the control air valve thereof also lead to the complicated control of the heat pump drying device.

Disclosure of Invention

The embodiment of the invention provides a heat pump drying device, which aims to solve the technical problem that the heat pump drying device in the prior art is complex to control for improving the efficiency of an air conditioner.

The embodiment of the present application provides a heat pump drying device, includes: the evaporator is arranged in the evaporation chamber, and the evaporation chamber is communicated with the external environment through a first air door; the condensation chamber is internally provided with a condenser, and the evaporation chamber is communicated with the condensation chamber through a second air door; the air supply chamber is communicated with the condensing chamber through a third air door and is communicated with the evaporation chamber through a fourth air door; an integral air valve member movably disposed on the evaporation chamber and the air supply chamber, the integral air valve member comprising: a first state of blocking the second damper, opening the first damper and the third damper; and a second state in which the first damper and the third damper are blocked and the second damper is opened.

In one embodiment, the integral wind valve member further comprises: and a third state of simultaneously opening the first air door, the second air door and the third air door, wherein in the third state, the first air door, the second air door and the third air door are all in an incomplete opening state.

In one embodiment, the heat pump drying device further comprises a driving assembly connected with the integrated air valve member for driving the integrated air valve member to move.

In one embodiment, a drive assembly comprises: a toothed member connected to the integral air valve member;

and the first motor is in driving connection with the rack piece and is used for driving the gear condition to drive the integral air valve piece to move.

In one embodiment, the first air door and the second air door are arranged on the evaporation chamber at intervals, the air supply chamber is arranged adjacent to the evaporation chamber, the third air door is arranged on the air supply chamber, and in a first state, the integral air valve part shields the second air door and avoids the first air door and the third air door; in a second state, the integral air valve piece shields the first air door and the third air door and avoids the second state of the second air door; and in a third state, the integral air valve component shields parts of the first air door, the second air door and the third air door.

In one embodiment, the integral air valve member is provided with a first avoiding hole, and the first avoiding hole is used for avoiding the first air door.

In one embodiment, the integral air valve member is provided with a second avoiding hole, and the second avoiding hole is used for avoiding a second air door.

In one embodiment, the first damper is provided in plurality, and correspondingly, the first avoidance hole is provided in plurality; the second air door is also provided with a plurality of second avoiding holes correspondingly.

In one embodiment, the plurality of first dampers are distributed on a side of the evaporation chamber and the plurality of second dampers are distributed on a top of the evaporation chamber, the integrated air valve member includes a top surface adapted to the top of the evaporation chamber and a side surface connected to the top surface adapted to the side of the evaporation chamber, the first avoidance holes are distributed on the side surface of the integrated air valve member, and the second avoidance holes are distributed on the top surface of the integrated air valve member.

In one embodiment, the first avoidance hole has a shape adapted to the shape of the first damper, the second avoidance hole has a shape adapted to the shape of the second damper, and the first damper and the second damper are holes having the same shape and provided in the evaporation chamber.

In one embodiment, the heat pump drying device comprises a fresh air fan connected to the evaporation chamber for supplying fresh air into the evaporation chamber.

In one embodiment, the heat pump drying apparatus further comprises an inner ambient chamber disposed adjacent to the air supply chamber and the condensing chamber.

In one embodiment, the condensing chamber is further provided with an air outlet communicated with the inner environment chamber.

In one embodiment, the heat pump drying device comprises a return fan connected between the air supply chamber and the inner environment chamber for returning air from the inner environment chamber to the air supply chamber.

In one embodiment, a third damper is provided at the top of the air supply chamber.

In one embodiment, the fourth air door is provided with an air return valve, the air return valve is used for blocking or opening the fourth air door, and the air return valve blocks the fourth air door when the integral air valve piece is in the first state; the return air valve opens the fourth air door when the integral air valve member is in the second state and the third state.

In one embodiment, the return air valve is rotatably disposed on the fourth air door, and the heat pump drying device further includes a second motor, the second motor is connected to the return air valve through a gear, and the second motor drives the return air valve to rotate so as to block or open the fourth air door.

In the embodiment, the heat pump drying device can be adjusted in different modes by only moving the integral air valve without arranging a complex air duct and a plurality of control air valve assemblies, and is convenient and quick.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. In the drawings:

fig. 1 is a schematic view of a heat pump drying apparatus according to the present invention;

fig. 2 is a schematic configuration diagram of an embodiment of a heat pump drying apparatus according to the present invention in mode one;

FIG. 3 is a schematic diagram of the embodiment of the heat pump drying appliance of FIG. 2 in mode two;

fig. 4 is an exploded view of the embodiment of the heat pump drying device of fig. 2.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following embodiments and the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

In the technical solution of the present invention, the external environment refers to an environment outside the space to be conditioned, and the internal environment refers to an environment inside the space to be conditioned.

Fig. 1 to 3 show an embodiment of the heat pump drying apparatus of the present invention, which includes an evaporation chamber 10, a condensation chamber 20, an air supply chamber 30, and an integral air valve member 40. An evaporator 11 is provided in the evaporation chamber 10, and a condenser 21 is provided in the condensation chamber 20. The evaporation chamber 10 communicates with the outside environment through a first damper a and communicates with the condensation chamber 20 through a second damper b. The air supply chamber 30 communicates with the condensing chamber 20 through a third damper c and communicates with the evaporating chamber 10 through a fourth damper d. The integrated air valve member 40 is movably disposed on the evaporation chamber 10 and the air supply chamber 30, and the integrated air valve member 40 includes: a first state in which the second damper b is blocked and the first damper a and the third damper c are opened; and a second state in which the first damper a and the third damper c are blocked and the second damper b is opened.

By applying the technical scheme of the invention, the evaporation chamber 10 cools and dehumidifies air through the evaporator 11 therein, and the condensation chamber 20 heats and dries the air through the condenser 21 therein. The integral air valve member 40 is moved to the first state, the integral air valve member 40 blocks the second air door b and opens the first air door a and the third air door c, so that the evaporation chamber 10 is only connected with the external environment, the air supply chamber 30, the condensation chamber 20 and the internal environment are communicated, the cold energy emitted by the evaporator 11 is carried to the external environment, the air flows in the air supply chamber 30, the condensation chamber 20 and the internal environment are continuously heated by the condenser 21, and the air temperature can be quickly increased. The integral air valve member 40 is moved to the second state, the integral air valve member 40 blocks the first air door a and the third air door c, and the second air door b is opened, so that the air flow in the air supply chamber 30 directly enters the evaporation chamber 10, and then enters the condensation chamber 20 from the evaporation chamber 10 to enter the internal environment, so that the condenser 21 in the condensation chamber 20 can continuously heat the heated air, and then the evaporator 11 in the evaporation chamber 10 cools and cools the air to remove the moisture in the internal environment, thereby dehumidifying the air in the closed space, and being applicable to the drying treatment of materials. By adopting the technical scheme of the invention, the adjustment of different modes of the heat pump drying device can be realized only by the movable integral air valve piece 40 without arranging a complicated air duct and a plurality of control air valve assemblies, and the heat pump drying device is convenient and quick.

As a preferred embodiment, the integral wind valve member 40 further comprises: and a third state of simultaneously opening the first damper a, the second damper b and the third damper c, wherein in the third state, the first damper a, the second damper b and the third damper c are in an incomplete opening state. When the air conditioner is in use, the integral air valve element 40 can be in a third state through the movable integral air valve element 40, the integral air valve element 40 can simultaneously open the third state of the first air door a, the second air door b and the third air door c, so that the air supply chamber 30 is communicated with the evaporation chamber 10 and the condensation chamber 20, the evaporation chamber is also communicated with the condensation chamber 20 and the external environment, part of fresh air in the external environment is discharged to the outside through the first air door a after entering the evaporation chamber 10, the rest enters the condensation chamber 20 through the second air door b, is mixed with air flow entering the condensation chamber 20 through the third air door c, and then is heated by the condenser 21 in the condensation chamber 20 and returns to the internal environment again, and the constant temperature control of air temperature can be realized through continuous circulation. Optionally, an air outlet 22 communicated with the internal environment is further disposed on the condensation chamber 20, and the air flow in the condensation chamber 20 blows towards the internal environment through the air outlet 22.

As shown in fig. 2 to 4, in the technical solution of the present invention, the heat pump drying device further includes a driving assembly 50, and the driving assembly 50 is connected to the integral wind valve 40 for driving the integral wind valve 40 to move. In use, automatic mode adjustment of the heat pump drying apparatus may be achieved by the drive assembly 50 driving the movement of the integral wind valve member 40. Optionally, in the technical solution of the present embodiment, the driving assembly 50 includes a rack member and a first motor. The rack member is connected to an integral wind valve member 40 and the first motor is drivingly connected to the rack member. When the wind valve is used, the first motor drives the gear to do linear motion, and then the integral wind valve piece 40 is driven to move.

Optionally, a third damper c is formed by opening 1 rectangular notch at the top of the air supply chamber 30 near the evaporation chamber 10, and the first motor is also disposed at the top of the air supply chamber 30.

As a specific embodiment, as shown in fig. 2 to 4, a first damper a and a second damper b are provided at an interval on the evaporation chamber 10. The air supply chamber 30 is disposed adjacent to the evaporation chamber 10, and the third damper c is disposed on the air supply chamber 30. In the first state, the integral air valve piece 40 shields the second air door b and avoids the first air door a and the third air door c; in the second state, the integral air valve member 40 covers the first air door a and the third air door c and avoids the second air door b; in the third state, the integral air valve member 40 covers a portion of the first damper a, the second damper b, and the third damper c. The integrated air valve member 40 can conveniently adjust the first damper a, the second damper b and the third damper c by arranging the air supply chamber 30 adjacent to the evaporation chamber 10, arranging the first damper a and the second damper b on the evaporation chamber 10 and arranging the third damper c on the air supply chamber 30.

In a more preferred embodiment, a first avoidance hole 41 is formed in the integrated air valve member 40, and the first avoidance hole 41 is used for avoiding the first damper a. Preferably, a second avoidance hole 42 is further formed in the integral wind valve member 40, and the second avoidance hole 42 is used for avoiding the second damper b. When the air valve is used, the first avoidance hole 41 and the second avoidance hole 42 are formed in the reasonable positions of the integral air valve piece 40, so that the first air door a and the second air door b can be blocked or opened ingeniously.

As shown in fig. 2 and 3, it is preferable that the first damper a is plural, and correspondingly, the first avoidance hole 41 is plural. The second damper b is also plural, and correspondingly, the second avoiding hole 42 is also plural. The plurality of first dampers a are provided to allow the evaporation chamber 10 to be more smoothly communicated with the external environment, and the plurality of second dampers b are provided to allow the evaporation chamber 10 to be more smoothly communicated with the condensation chamber 20.

As a specific embodiment, as shown in fig. 2 to 4, a plurality of first dampers a are distributed at the side of the evaporation chamber 10, and a plurality of second dampers b are distributed at the top of the evaporation chamber 10. The integrated wind valve member 40 includes a top surface adapted to the top of the evaporation chamber 10 and side surfaces connected to the top surface adapted to the side portions of the evaporation chamber 10, the first escape holes 41 are distributed on the side surfaces of the integrated wind valve member 40, and the second escape holes 42 are distributed on the top surface of the integrated wind valve member 40. In use, the side of the evaporation chamber 10 is connected to the external environment through the first damper a, and the top of the evaporation chamber 10 is connected to the condensation chamber 20 through the second damper b. In a preferred embodiment, the first avoiding hole 41 has a shape corresponding to the shape of the first damper a, the second avoiding hole 42 has a shape corresponding to the shape of the second damper b, and the first damper a and the second damper b are holes having the same shape and opened in the evaporation chamber 10. When in use, the first air door a and the second air door b are staggered, and the first avoidance hole 41 and the second avoidance hole 42 are arranged at proper positions on the integral air valve member 40, so that the different air doors can be switched. Preferably, in the technical solution of this embodiment, the first damper a and the second damper b are circular holes with the same size, and the first avoidance hole 41 and the second avoidance hole 42 are also circular holes with the same size. Specifically, the first dampers a are arranged in an array on the side surface of the evaporation chamber 10, the second dampers b are also arranged in an array on the top surface of the evaporation chamber 10, and the second dampers b and the first dampers a are staggered in the moving direction of the integral type air valve member 40, so that the integral type air valve member 40 can realize the switching of the first state, the second state and the third state. Specifically, on the integral wind valve member 40, the distance between the circular holes in the same row/column is D, the distance between the rows/columns is D/2, and the diameter D of the circular holes is less than D/2; the staggered distance of the hole sites of the adjacent rows/adjacent columns is D/2.

Optionally, in the technical solution of this embodiment, the third damper c is opened at the top of the air supply chamber 30, and the integral air valve 40 blocks the third damper c.

Preferably, in the technical solution of this embodiment, as shown in fig. 1 to 4, the heat pump drying device further includes an inner environment chamber 90, the inner environment chamber 90 is disposed adjacent to the air supply chamber 30 and the condensation chamber 20, and the condensation chamber 20 is communicated with the inner environment chamber 90 through the air outlet 22. As shown in fig. 2 and 3, in the solution of the present embodiment, the heat pump drying device includes a return fan 70, and the return fan 70 is connected between the air supply chamber 30 and the inner environment chamber 90. In use, the return air fan 70 is used to return air from the internal environment into the air supply compartment 30.

Specifically, as shown in fig. 4, the left side plate 101, the right side plate 102, the front plate 103, the rear plate 104, and the top cover 105 enclose a space in which the middle partition 106 is disposed. The right space is an inner ambient chamber 90, the evaporation chamber 10 and the air supply chamber 30 are arranged at the bottom of the left space, and the upper part of the left space forms a condensation chamber 20. The fresh air blower 60 is arranged on the left side of the left side plate 101, the return air blower 70 is arranged on the right side of the middle partition plate 106, and vent holes communicated with the first air door a are further formed in the front panel 103 and the rear panel 104.

As another alternative embodiment, in addition to the structure of the inner environment chamber 90 shown in the figure, the inner environment chamber 90 may be a space structure separately provided and connected to the air supply chamber 30 and the condensation chamber 20 through air ducts, respectively.

Optionally, as a preferred embodiment, a return air valve 80 is provided on the fourth damper d. In use, the return air valve 80 is used to block or open the fourth damper d. When the integral air valve member 40 is in the first state, the return air valve 80 blocks the fourth air door d; the return air valve 80 opens the fourth damper d when the integral air valve member 40 is in the second and third states. Preferably, the return air valve 80 is also activated by an actuator. Alternatively, the heat pump drying device includes a second motor disposed on the evaporation chamber 10, and the return air valve 80 is rotatably disposed on the fourth damper d and is connected to the second motor through a gear. The second motor drives the return air valve 80 to rotate to block or open the fourth damper d.

As can be seen from the above, the heat pump drying device of the present invention has three modes in total:

mode one

The integral air valve member 40 is in the initial position at the far left end, and the return air valve 80 is closed, corresponding to: the third damper c and the first damper a are opened, and the second damper b and the fourth damper d are closed.

The condensing chamber 20, the inner ambient chamber 90 and the air supply chamber 30 form a closed space, and the internal air is circulated by the return fan 70 while being continuously heated by the condenser 21.

The fresh air fan 60 drives fresh air outside to enter the evaporation chamber 10, and then the fresh air passes through the evaporator 11 and is discharged from the first air door a. Since the cold energy emitted from the evaporator 11 is carried to the outside, the temperature of the air in the internal ambient room 90 is rapidly raised.

Mode two

Under the driving of the driving assembly 50, the integral air valve member 40 reaches the rightmost end position, and the return air valve 80 is opened, which corresponds to: the third damper c and the first damper a are closed, and the second damper b and the fourth damper d are opened.

The evaporation chamber 10, the condensation chamber 20, the inner environment chamber 90 and the air supply chamber 30 form a closed space, the internal air circularly flows under the driving of the air return fan 70, meanwhile, the internal air is continuously heated by the condenser 21 and is continuously cooled by the evaporator 11, and the condensed water generated on the evaporator 11 is discharged to the outdoor space, so that the air in the closed space can be dehumidified, and the dehumidifying device can be applied to the drying treatment of materials.

Mode three

Under the drive of the drive assembly 50, the integral air valve member 40 reaches the intermediate position, and the return air valve 80 is opened, all the dampers are in the open state, but the third damper c, the second damper b and the first damper a are in the approximately half-open state.

The evaporation chamber 10, the condensation chamber 20, the inner ambient chamber 90 and the air supply chamber 30 form an open space, and the evaporation chamber 10 communicates with the outdoor air through a first damper a. At this time, the fresh air fan 60 and the return air fan 70 are driven simultaneously, outdoor fresh air enters and is mixed with part of return air passing through the fourth air door d in the evaporation chamber 10 and then passes through the evaporator 11, part of mixed air is discharged to the outdoor through the first air door a, and the rest of mixed air passes through the second air door b and is mixed with other return air passing through the third air door c again and then is heated by the condenser 21 and returns to the inlet of the return air fan 70 again, so that the constant temperature control of the air temperature in the inner environment chamber 90 can be realized through continuous circulation.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat pump drying apparatus, comprising:

the evaporator comprises an evaporation chamber (10), wherein an evaporator (11) is arranged in the evaporation chamber (10), and the evaporation chamber (10) is communicated with an external environment through a first air door (a);

the condensation chamber (20), a condenser (21) is arranged in the condensation chamber (20), and the evaporation chamber (10) is communicated with the condensation chamber (20) through a second air door (b);

an air supply chamber (30) communicated with the condensation chamber (20) through a third air door (c) and communicated with the evaporation chamber (10) through a fourth air door (d);

a unitary air valve member (40) movably disposed over the evaporation chamber (10) and the air supply chamber (30), the unitary air valve member (40) comprising: a first state of blocking the second damper (b), opening the first damper (a) and the third damper (c); and a second state of blocking the first damper (a) and the third damper (c) and opening the second damper (b);

the unitary wind valve member (40) further comprises: a third state in which the first damper (a), the second damper (b), and the third damper (c) are simultaneously opened, in which the first damper (a), the second damper (b), and the third damper (c) are all in an incompletely opened state;

the first air door (a) and the second air door (b) are arranged on the evaporation chamber (10) at intervals, the air supply chamber (30) is arranged adjacent to the evaporation chamber (10), the third air door (c) is arranged on the air supply chamber (30), and in the first state, the integral air valve member (40) shields the second air door (b), and avoids the first air door (a) and the third air door (c); in the second state, the integral air valve piece (40) shields the first air door (a) and the third air door (c) and avoids the second air door (b); in the third state, the integral wind valve member (40) shields parts of the first, second and third dampers (a, b, c);

the heat pump drying device further comprises a driving assembly (50), wherein the driving assembly (50) is connected with the integral wind valve piece (40) and used for driving the integral wind valve piece (40) to move.

2. The heat pump drying appliance according to claim 1, wherein the driving assembly (50) comprises:

a toothed member connected to the integral wind valve member (40);

and the first motor is in driving connection with the rack piece and is used for driving the gear condition to drive the integral wind valve piece (40) to move.

3. The heat pump drying device according to claim 1, wherein the integral air valve member (40) is provided with a first avoidance hole (41), and the first avoidance hole (41) is used for avoiding the first air door (a).

4. The heat pump drying device according to claim 3, wherein a second avoidance hole (42) is formed in the integral air valve member (40), and the second avoidance hole (42) is used for avoiding the second air door (b).

5. The heat pump drying apparatus according to claim 4, wherein the first damper (a) is plural, and correspondingly, the first avoiding hole (41) is plural; the second air door (b) is also provided with a plurality of corresponding second avoidance holes (42).

6. The heat pump drying apparatus according to claim 5, wherein a plurality of the first dampers (a) are distributed on the side of the evaporation chamber (10), a plurality of the second dampers (b) are distributed on the top of the evaporation chamber (10), the integrated wind valve member (40) includes a top surface adapted to the top of the evaporation chamber (10) and a side surface connected to the top surface adapted to the side of the evaporation chamber (10), the first escape holes (41) are distributed on the side surface of the integrated wind valve member (40), and the second escape holes (42) are distributed on the top surface of the integrated wind valve member (40).

7. The heat pump drying device according to claim 6, wherein the first avoidance hole (41) is shaped to fit the shape of the first damper (a), the second avoidance hole (42) is shaped to fit the shape of the second damper (b), and the first damper (a) and the second damper (b) are identically shaped holes opened in the evaporation chamber (10).

8. The heat pump drying device according to claim 1, characterized in that the heat pump drying device comprises a fresh air fan (60), and the fresh air fan (60) is connected to the evaporation chamber (10) for supplying fresh air into the evaporation chamber (10).

9. The heat pump drying appliance according to claim 1, further comprising an inner ambient chamber (90), the inner ambient chamber (90) being disposed adjacent to the air supply chamber (30) and the condensing chamber (20).

10. The heat pump drying apparatus according to claim 9, wherein the condensing chamber (20) is further provided with an air outlet (22) communicating with the inner ambient chamber (90).

11. The heat pump drying apparatus as claimed in claim 10, wherein said heat pump drying apparatus includes a return fan (70), said return fan (70) being connected between said air supply chamber (30) and said inner ambient chamber (90) for returning air from said inner ambient chamber (90) into said air supply chamber (30).

12. The heat pump drying appliance according to claim 1, wherein the third damper (c) is opened at the top of the air supply chamber (30).

13. The heat pump drying apparatus according to claim 1, wherein a return air valve (80) is provided on the fourth damper (d), the return air valve (80) being configured to block or open the fourth damper (d), the return air valve (80) blocking the fourth damper (d) when the integral air valve member (40) is in the first state; the return air valve (80) opens the fourth damper (d) when the unitary air valve member (40) is in the second and third states.

14. The heat pump drying device according to claim 13, wherein the return air valve (80) is rotatably disposed on a fourth air door (d), and the heat pump drying device further comprises a second motor, the second motor is connected with the return air valve (80) through a gear, and the second motor drives the return air valve (80) to rotate so as to realize the blocking or opening of the fourth air door (d).