Heat pump drying device

Abstract

The invention discloses a heat pump drying device, comprising a compressor, a first heat exchanger, a second heat exchanger, and a third heat exchanger; the compressor comprises an inlet and an outlet; the first heat exchanger and the second heat exchanger are arranged in a drying room; the third heat exchanger is arranged outside the drying room; the first heat exchanger, the second heat exchanger, and the third heat exchanger are connected with the inlet or the outlet through a plurality of controllable switches to form a circulation system; the working modes comprise a heating mode and a temperature stabilizing mode; in the heating mode, each controllable switch is controlled to make the third heat exchanger an evaporator; one of the first heat exchanger and the second heat exchanger is an evaporator, and the other is a condenser; in the temperature stabilizing mode, each controllable switch is controlled to make the first heat exchanger or the second heat exchanger a condenser, the second heat exchanger or the first heat exchanger an evaporator, or the first heat exchanger or the second heat exchanger and the third heat exchanger a condenser, and the second heat exchanger or the first heat exchanger an evaporator. The heating speed and the temperature control accuracy are improved.

Description

Technical Field

[0001] The invention relates to the technical field of drying equipment, and in particular to a heat pump drying device. Background Art

[0002] Drying is an important process in the production process of industry, agricultural and sideline products and food processing. The drying process is a high energy consumption process. The drying device and its drying process control are closely related to the quality of the dried processed products, and are also closely related to production efficiency, cost, energy consumption, etc.

[0003] The heat pump drying equipment has a significant dehumidification effect and can quickly dry materials at room temperature, thereby ensuring the quality and color of the dried materials and producing high-quality products. In the prior art, the closed dehumidification heat pump system uses the principle of condensation dehumidification, using an evaporator to cool the wet air to below the dew point temperature, and after the water is precipitated, the condenser is used to heat the cooled dry air, thereby achieving the purpose of dehumidification and drying.

[0004] However, in the early stage of material drying, the drying room is low in temperature and humidity, and it is urgently needed to quickly heat up and dehumidify. At this time, only the power of the compressor is continuously input into the system, and no heat is absorbed from the outside, resulting in slow heating of the unit and low energy efficiency.

[0005] When the mid-term temperature stabilization stage is running for a long time, energy is continuously input into the system in the form of compressor power, causing the system temperature to continue to rise, which is not conducive to the control of the drying temperature in the drying room.

[0006] In the later stage of material drying, the moisture in the circulating air will become less and less, the evaporator will obtain less and less water latent heat from the return air, and the circulating air will be difficult to heat up. At this time, an electric heater is also needed to heat the circulating air to meet the temperature requirements of the drying process. It can be seen that this simple closed drying system also consumes a lot of electricity. Summary of the invention

[0007] In order to solve the problems of slow initial heating speed, high energy consumption and difficulty in precise temperature control in the middle and late stages of closed heat pump drying devices in the prior art, the present invention provides a heat pump drying device, which increases the initial heating speed, reduces energy consumption, improves temperature control accuracy and reduces the difficulty of precise temperature control.

[0008] In order to achieve the above object, the present invention adopts the following technical scheme:

[0009] The present invention provides a heat pump drying device for drying articles to be dried in a drying room, comprising:

[0010] A compressor including an inlet and an outlet;

[0011] A first heat exchanger, which is arranged in the drying room;

[0012] A second heat exchanger, which is arranged in the drying room;

[0013] A third heat exchanger, which is arranged outside the drying room;

[0014] The first heat exchanger, the second heat exchanger, and the third heat exchanger are connected to the inlet or the outlet through a plurality of controllable switches to form a circulation system;

[0015] Working modes include:

[0016] In the heating mode, each of the controllable switches is controlled so that the third heat exchanger is an evaporator; one of the first heat exchanger and the second heat exchanger is an evaporator and the other is a condenser;

[0017] In the temperature stabilization mode, each of the controllable switches is controlled so that the first heat exchanger or the second heat exchanger is a condenser, the second heat exchanger or the first heat exchanger is an evaporator, or the first heat exchanger or the second heat exchanger and the third heat exchanger are a condenser, and the second heat exchanger or the first heat exchanger is an evaporator.

[0018] As a specific structural design of the heat pump drying device,

[0019] The first heat exchanger includes a first port and a second port; the second heat exchanger includes a third port and a fourth port; the third heat exchanger includes a fifth port and a sixth port; there are two controllable switches, namely a first controllable switch and a second controllable switch;

[0020] The second port, the fourth port, and the sixth port are connected to each other; the first port is connected to the outlet; the third port is connected to the inlet; the first controllable switch and the second controllable switch are respectively connected to the third heat exchanger to control the connection or disconnection between the fifth port and the outlet, and the connection or disconnection between the fifth port and the inlet;

[0021] A controller is connected to the compressor, the first controllable switch, and the second controllable switch respectively; and is configured to:

[0022] When in the heating mode, controlling the first controllable switch and the second controllable switch to operate so that the fifth port is connected to the inlet and disconnected from the outlet;

[0023] When in the temperature stabilization mode, the first controllable switch and the second controllable switch are controlled to operate so that the fifth port is disconnected from the inlet, disconnected from the outlet, or connected.

[0024] Furthermore, it also includes a dry-bulb temperature sensor 7, which is arranged on the first heat exchanger or the second heat exchanger, connected to the controller, and detects the return air dry-bulb temperature;

[0025] The controller receives the return air dry bulb temperature and is configured to be provided with a set dry bulb temperature and a first temperature, and determines the relationship between the return air dry bulb temperature and the set dry bulb temperature;

[0026] When the set dry-bulb temperature minus the return air dry-bulb temperature is greater than or equal to the first temperature, the heating mode is set;

[0027] When the set dry-bulb temperature minus the return air dry-bulb temperature is less than the first temperature, the temperature-stabilizing mode is set.

[0028] Furthermore, it also includes a wet-bulb temperature sensor, which is arranged on the first heat exchanger or the second heat exchanger, connected to the controller, and detects the return air wet-bulb temperature;

[0029] The controller receives the return air wet-bulb temperature and is configured to be provided with a set wet-bulb temperature and a second temperature, and determines the relationship between the return air wet-bulb temperature and the set wet-bulb temperature in the temperature-stabilizing mode;

[0030] If the set wet-bulb temperature minus the return air wet-bulb temperature is greater than or equal to the second temperature, set the temperature to a stable heating mode;

[0031] If the set wet-bulb temperature minus the return air wet-bulb temperature is less than the second temperature, the stable cooling mode is set.

[0032] Further, the controller is configured to set a third temperature and determine the relationship between the set dry-bulb temperature and the return air dry-bulb temperature when in the stable heating mode;

[0033] If the return air dry-bulb temperature minus the set dry-bulb temperature is greater than or equal to the third temperature, the first controllable switch and the second controllable switch are controlled to disconnect the fifth port from the inlet and the outlet, and the compressor stops running;

[0034] If the return air dry-bulb temperature minus the set dry-bulb temperature is less than the third temperature, the first controllable switch and the second controllable switch are controlled to disconnect the fifth port from the inlet and the outlet, and the compressor is operated.

[0035] Further, the controller is configured to be set with a fourth temperature, and to determine the relationship between the set dry-bulb temperature and the return air dry-bulb temperature when in the stable cooling mode;

[0036] If the set dry-bulb temperature minus the return air dry-bulb temperature is greater than or equal to the fourth temperature, the first controllable switch and the second controllable switch are controlled to disconnect the fifth port from the inlet and the outlet, and the compressor is operated;

[0037] If the set dry-bulb temperature minus the return air dry-bulb temperature is less than the fourth temperature, the first controllable switch and the second controllable switch are controlled to connect the fifth port with the outlet and disconnect the fifth port with the inlet.

[0038] Preferably, the first temperature ranges from 0 to 5°C; the second temperature ranges from -5 to 0°C; the third temperature ranges from -3 to 3°C; and the fourth temperature ranges from -5 to 2°C.

[0039] Further preferably, the first temperature is 2°C; the second temperature is -2°C; the third temperature range is 0°C; and the fourth temperature range is -2°C.

[0040] Preferably, it also includes:

[0041] a pipe temperature sensor, which is disposed on the third heat exchanger and connected to the controller to detect the pipe temperature of the third heat exchanger;

[0042] The controller receives the pipe temperature and is configured to determine the pipe temperature in the heating mode;

[0043] When the piping temperature is greater than 0°C, the first controllable switch and the second controllable switch are controlled to operate so that the fifth port is connected to the inlet and disconnected from the outlet; when the piping temperature is less than or equal to 0°C, the first controllable switch and the second controllable switch are controlled to operate so that the fifth port is connected to the outlet and disconnected from the inlet.

[0044] Furthermore, it also includes:

[0045] An outdoor temperature sensor, which is arranged outside the drying room and connected to the controller, is used to detect the outdoor return air temperature;

[0046] an air supply device connected in series between the second port and the inlet;

[0047] A controllable opening switch, which is connected in series with the air supply device and electrically connected with the controller;

[0048] The controller receives the outdoor return air temperature and is configured to determine the outdoor return air temperature when the heating mode is on and the fifth port is connected to the inlet and disconnected from the outlet;

[0049] When the outdoor return air temperature is greater than 0°C, the controllable opening switch is controlled to close;

[0050] When the outdoor return air temperature is less than or equal to 0° C., the controllable opening switch is controlled to open.

[0051] The technical solution of the present invention has the following technical effects compared with the prior art:

[0052] A heat pump drying device of the present invention forms different working modes: a heating mode and a temperature stabilizing mode by arranging a third heat exchanger outside a drying room and forming different circulation systems through the third heat exchanger, the first heat exchanger and the second heat exchanger; the heating mode is executed when the initial low temperature needs to be quickly heated up, and the third heat exchanger and the first heat exchanger or the second heat exchanger are both evaporators, thereby improving the problem of low heating efficiency of the closed heat pump drying device that only relies on the power of the compressor for heating; in addition, when the temperature rises to near the set temperature, the temperature stabilizing mode is executed, and the third heat exchanger stops working or becomes a condenser, and the first heat exchanger and the second heat exchanger are respectively a condenser and an evaporator, thereby preventing the drying room from heating up too quickly and overheating, improving the temperature control accuracy in the drying room, and improving the drying quality of the dried items. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0054] Figure 1 A schematic diagram of a circulation system of a first embodiment of a heat pump drying device of the present invention;

[0055] Figure 2 A schematic diagram of a circulation system of a second embodiment of a heat pump drying device of the present invention;

[0056] Figure 3 A schematic diagram of a circulation system of a third embodiment of a heat pump drying device of the present invention;

[0057] Figure 4 A schematic diagram of a circulation system of a fourth embodiment of a heat pump drying device of the present invention;

[0058] Figure 5 A schematic diagram of a circulation system of a fifth embodiment of a heat pump drying device of the present invention;

[0059] Figure 6 It is a flow chart of an embodiment of a heat pump drying device of the present invention;

[0060] Figure 7 It is a flow chart of a fourth embodiment of a heat pump drying device of the present invention;

[0061] Figure 8 This is a flow chart of a fifth embodiment of a heat pump drying device of the present invention.

[0062] Reference numerals:

[0063] 1. Compressor; 2. First heat exchanger; 3. Second heat exchanger; 4. Third heat exchanger; DCF1, First solenoid valve; DCF2, Second solenoid valve; 7. Dry bulb temperature sensor; 8. Wet bulb temperature sensor; 9. Pipe temperature sensor; 10. Outdoor temperature sensor; 20. Air supply device; PZF2, Solenoid expansion valve; PZF3, Controllable opening solenoid valve; STF1, First four-way valve; STF2, Second four-way valve; 11. Outlet; 12. Inlet; 21, First port; 22, Second port; 31, Third port; 32, Fourth port; 41, Fifth port; 42, Sixth port; a, First temperature; b, Second temperature; c, Third temperature; d, Fourth temperature; Tsg, Set dry bulb temperature; Thg, Return air dry bulb temperature; Tss, Set wet bulb temperature; Thg, Return air wet bulb temperature; Tp, Pipe temperature; Tw, Outdoor return air temperature. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] In the description of the present invention, it should be noted that, 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. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0066] A heat pump drying device of the present invention includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, and a third heat exchanger 4; the compressor 1 includes an inlet 12 and an outlet 11; the first heat exchanger 2, the second heat exchanger 3, and the third heat exchanger 4 are connected to the outlet 11 or the inlet 12 of the compressor 1 through a plurality of controllable switches, and each controllable switch controls the first heat exchanger 2, the second heat exchanger 3, and the third heat exchanger 4 to be adjacently connected to the inlet 12 or the outlet 11, thereby forming a circulation system having an evaporator and a condenser.

[0067] The heat pump drying device of the present invention includes a heating mode and a temperature stabilization mode. When the low-temperature initial heating in the drying room needs to be quickly heated up, the heating mode is executed; the controllable switches are controlled to make the first heat exchanger 2 or the second heat exchanger 3 a condenser, and correspondingly, the second heat exchanger 3 or the first heat exchanger 2 and the third heat exchanger 4 are evaporators, and the third heat exchanger 4 absorbs heat outside the drying room to increase the temperature in the drying room, thereby improving the closed heat pump drying device in which only a heat exchanger is set in the drying room, and the temperature is increased only by the power form of the compressor 1, thereby solving the problems of low heating efficiency and high energy consumption.

[0068] When the temperature in the drying room rises to the required temperature or the set temperature, the temperature stabilization mode is executed to control the actions of the controllable switches so that the first heat exchanger 2 or the second heat exchanger 3 and the third heat exchanger 4 are condensers, and correspondingly, the second heat exchanger 3 or the first heat exchanger 2 is an evaporator to maintain the temperature in the drying room and perform condensation and dehumidification;

[0069] Alternatively, when the temperature in the drying room rises to near the required temperature, that is, near the set temperature, the temperature stabilization mode is executed, and the controllable switches are controlled to act as a condenser, and correspondingly, the second heat exchanger 3 or the first heat exchanger 2 is used as an evaporator, and the third heat exchanger 4 is not connected to the circulation system, so that the drying room is slowly heated up and condensed and dehumidified.

[0070] The third heat exchanger 4 is provided so that the heat pump drying device is a condenser or is not connected to a circulation system in the steady temperature mode, making the temperature control in the drying room easier and more accurate.

[0071] The system structure, working principle and process of a heat pump drying device of the present invention are described in detail below through specific embodiments.

[0072] Embodiment 1

[0073] Reference Figure 1 and Figure 6The heat pump drying device of this embodiment includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, a controller, a dry-bulb temperature sensor 7, a wet-bulb temperature sensor 8, a first controllable switch, and a second controllable switch; the first controllable switch is a first solenoid valve DCF1; the second controllable switch is a second solenoid valve DCF2.

[0074] The compressor 1 includes an inlet 12 and an outlet 11 ; the first heat exchanger 2 includes a first port 21 and a second port 22 ; the second heat exchanger 3 includes a third port 31 and a fourth port 32 ; the third heat exchanger 4 includes a fifth port 41 and a sixth port 42 .

[0075] The second port 22, the fourth port 32, and the sixth port 42 are connected to each other; the first port 21 is connected to the outlet 11; the third port 31 is connected to the inlet 12; the fifth port 41 is connected to the outlet 11 through the first solenoid valve DCF1 and to the inlet 12 through the second solenoid valve DCF2; the first solenoid valve DCF1 and the second solenoid valve DCF2 are respectively connected to the controller, and the controller controls whether they are connected or disconnected.

[0076] The dry-bulb temperature sensor 7 and the wet-bulb temperature sensor 8 are respectively arranged on the second heat exchanger 3 and are respectively connected to the controller for detecting the return air dry-bulb temperature Thg and the return air wet-bulb temperature Thg in the drying room.

[0077] The controller receives the return air dry bulb temperature Thg and the return air wet bulb temperature Thg and is configured to be provided with a set dry bulb temperature Tsg and a first temperature a, and determines the relationship between the return air dry bulb temperature Thg and the set dry bulb temperature Tsg.

[0078] When the set dry-bulb temperature Tsg minus the wind-back dry-bulb temperature Thg is greater than or equal to the first temperature a, it is in the heating mode, that is, the controller controls the first solenoid valve DCF1 to close and the second solenoid valve DCF2 to open, the first heat exchanger 2 is a condenser, the second heat exchanger 3 and the third heat exchanger 4 are evaporators, and the third heat exchanger absorbs heat from outside the drying room and provides heat to the drying room, so that the temperature in the drying room rises rapidly.

[0079] When the set dry-bulb temperature Tsg minus the wind-back dry-bulb temperature Thg is less than the first temperature a, it is in the temperature-stabilizing mode, that is, the controller controls the first solenoid valve DCF1 to be closed or opened, and the second solenoid valve DCF2 to be closed, so that the first heat exchanger 2 is a condenser, the second heat exchanger 3 is an evaporator, and the third heat exchanger 4 is a condenser or is not connected to the circulation system, so that the temperature in the drying room is maintained for dehumidification or the temperature is slowly increased for dehumidification, and dehumidification is achieved while ensuring the temperature control accuracy.

[0080] Preferably, the controller is configured to also be provided with a set wet-bulb temperature Tss, a second temperature b, a third temperature c, a fourth temperature d, and to determine the relationship between the return air wet-bulb temperature Thg and the set wet-bulb temperature Tss in a steady temperature mode.

[0081] When the set wet-bulb temperature Tss minus the return air wet-bulb temperature Thg is greater than or equal to the second temperature b, it is a stable heating mode; if at this time the return air dry-bulb temperature Thg minus the set dry-bulb temperature Tsg is greater than or equal to the third temperature c, the first solenoid valve DCF1 and the second solenoid valve DCF2 are controlled to be closed, and the compressor 1 stops running; if at this time the return air dry-bulb temperature Thg minus the set dry-bulb temperature Tsg is less than the third temperature c, the first solenoid valve DCF1 and the second solenoid valve DCF2 are controlled to be closed, and the compressor 1 is operated, which is a closed heat pump drying system to achieve slow heating and condensation dehumidification.

[0082] When the wet-bulb temperature Tss minus the rheumatoid-bulb temperature Thg is set to be less than the second temperature b, it is in the stable temperature holding mode; if the dry-bulb temperature Tsg minus the rheumatoid-bulb temperature Thg is set to be greater than or equal to the fourth temperature d, the first solenoid valve DCF1 is controlled to be closed and the second solenoid valve DCF2 is controlled to be closed, and the closed heat pump drying system is operated to achieve slow heating and condensation dehumidification; if the dry-bulb temperature Tsg minus the rheumatoid-bulb temperature Thg is set to be less than the fourth temperature d, the first solenoid valve DCF1 is controlled to be opened and the second solenoid valve DCF2 is controlled to be closed, that is, the third heat exchanger 4 is a condenser, so as to maintain the temperature and dehumidify in the drying room.

[0083] Preferably, the value range of the first temperature a is 0~5°C; the value range of the second temperature b is -5~0°C; the value range of the third temperature c is -3~3°C; the value range of the fourth temperature d is -5~2°C.

[0084] Preferably, the value of the first temperature a is 2°C; the value of the second temperature b is -2°C; the value of the third temperature c is 0°C; and the value of the fourth temperature d is -2°C.

[0085] Embodiment 2

[0086] Reference Figure 2 and Figure 6 The heat pump drying device of this embodiment further includes a pipe temperature sensor 9 on the basis of the first embodiment, which is arranged on the third heat exchanger 4 and connected to the controller for detecting the pipe temperature Tp of the third heat exchanger 4 .

[0087] The controller receives the pipe temperature Tp and is configured to judge the pipe temperature Tp when in the heating mode; when the pipe temperature Tp is less than or equal to 0°C, the first solenoid valve DCF1 is controlled to open and the second solenoid valve DCF2 is controlled to close, so that the third heat exchanger 4 is a condenser and runs the defrost mode.

[0088] Embodiment 3

[0089] Reference Figure 3 and Figure 6 The heat pump drying device of this embodiment further includes an outdoor temperature sensor 10, an air supply device 20, and a controllable opening solenoid valve PZF3 on the basis of the second embodiment.

[0090] The air supply device 20 is connected in series with the controllable opening solenoid valve PZF3, and its two ends are connected to the second port 22 and the inlet 12 respectively; the controllable opening solenoid valve PZF3 is connected to the controller, and the controller controls the action to connect or disconnect the air supply device 20 between the second port 22 and the inlet 12.

[0091] The outdoor temperature sensor 10 is arranged on the third heat exchanger 4 and connected to the controller for detecting the outdoor return air temperature Tw; the controller receives the outdoor return air temperature Tw and is configured to determine the outdoor return air temperature Tw in the heating mode;

[0092] When the outdoor return air temperature Tw is greater than 0°C, the controller controls the controllable opening solenoid valve PZF3 to close, that is, the air supply device 20 is not connected between the second port 22 and the inlet 12, and the compressor 1 is not supplied with air;

[0093] When the outdoor return air temperature Tw is less than or equal to 0° C., the controller controls the controllable opening solenoid valve PZF3 to open, connects the air supply device 20 between the second port 22 and the inlet 12, supplies air to the compressor 1, and improves the efficiency of the compressor 1.

[0094] Preferably, the controller can control the opening of the controllable opening solenoid valve PZF3 according to the value of the outdoor return air temperature Tw, and control the amount of air supplied to the compressor 1 by the air supply device 20, so as to improve the efficiency of the compressor 1.

[0095] Embodiment 4

[0096] Reference Figure 4 , Figure 6 and Figure 7 The heat pump drying device of this embodiment includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, a controller, a dry-bulb temperature sensor 7, and a wet-bulb temperature sensor 8; each controllable switch is a first four-way valve STF1, a first solenoid valve DCF1, and a second solenoid valve DCF2.

[0097] The compressor 1 includes an inlet 12 and an outlet 11 ; the first heat exchanger 2 includes a first port 21 and a second port 22 ; the second heat exchanger 3 includes a third port 31 and a fourth port 32 ; the third heat exchanger 4 includes a fifth port 41 and a sixth port 42 .

[0098] The second port 22, the fourth port 32, and the sixth port 42 are connected to each other; the first port 21, the outlet 11, the third port 31, and the inlet 12 are respectively connected to the four ports of the first four-way valve STF1, so that when the first four-way valve STF1 is closed, the first port 21 is connected to the outlet 11, and the third port 31 is connected to the inlet 12; when the first four-way valve STF1 is opened, the first port 21 is connected to the inlet 12, and the third port 31 is connected to the outlet 11; the fifth port 41 is connected to the first port 21 through the first solenoid valve DCF1, and is connected to the third port 31 through the second solenoid valve DCF2; the first solenoid valve DCF1 and the second solenoid valve DCF2 are respectively connected to the controller, and the controller controls them to be connected or disconnected. The first four-way valve STF1 is connected to the controller, and the controller controls it to be closed or opened.

[0099] The dry-bulb temperature sensor 7 and the wet-bulb temperature sensor 8 are respectively arranged on the second heat exchanger 3 and are respectively connected to the controller for detecting the return air dry-bulb temperature Thg and the return air wet-bulb temperature Thg in the drying room.

[0100] The controller receives the return air dry bulb temperature Thg and the return air wet bulb temperature Thg and is configured to be provided with a set dry bulb temperature Tsg and a first temperature a, and determines the relationship between the return air dry bulb temperature Thg and the set dry bulb temperature Tsg.

[0101] When the set dry-bulb temperature Tsg minus the wind-back dry-bulb temperature Thg is greater than or equal to the first temperature a, it is in the heating mode, that is, the controller controls the first four-way valve STF1 to close, the first solenoid valve DCF1 to close, and the second solenoid valve DCF2 to open. The first heat exchanger 2 is a condenser, the second heat exchanger 3 and the third heat exchanger 4 are evaporators. The third heat exchanger absorbs heat from outside the drying room to assist in heating the drying room, thereby increasing the heating rate in the drying room and reducing power consumption.

[0102] When the set dry-bulb temperature Tsg minus the wind-back dry-bulb temperature Thg is less than the first temperature a, it is in the temperature-stabilizing mode, that is, the controller controls the first four-way valve STF1 to be closed, the first solenoid valve DCF1 to be closed or opened, and the second solenoid valve DCF2 to be closed, so that the first heat exchanger 2 is a condenser, the second heat exchanger 3 is an evaporator, and the third heat exchanger 4 is a condenser or is not connected to the circulation system, so that the temperature in the drying room is maintained for dehumidification or the temperature is slowly increased for dehumidification, and dehumidification is achieved while ensuring the temperature control accuracy.

[0103] Preferably, the controller is configured to also be provided with a set wet-bulb temperature Tss, a second temperature b, a third temperature c, a fourth temperature d, and to determine the relationship between the return air wet-bulb temperature Thg and the set wet-bulb temperature Tss in the steady temperature mode.

[0104] When the set wet-bulb temperature Tss minus the return air wet-bulb temperature Thg is greater than or equal to the second temperature b, it is in the stable heating mode; if at this time the return air dry-bulb temperature Thg minus the set dry-bulb temperature Tsg is greater than or equal to the third temperature c, the first solenoid valve DCF1 and the second solenoid valve DCF2 are controlled to be closed, and the compressor 1 stops running; if at this time the return air dry-bulb temperature Thg minus the set dry-bulb temperature Tsg is less than the third temperature c, the first solenoid valve DCF1 and the second solenoid valve DCF2 are controlled to be closed, and the compressor 1 is operated, which is a closed heat pump drying system, and slow heating and dehumidification are performed to achieve slow heating and condensation dehumidification.

[0105] When the wet-bulb temperature Tss minus the rheumatoid-bulb temperature Thg is set to be less than the second temperature b, it is in the stable temperature holding mode; if the dry-bulb temperature Tsg minus the rheumatoid-bulb temperature Thg is set to be greater than or equal to the fourth temperature d, the first solenoid valve DCF1 and the second solenoid valve DCF2 are controlled to be closed, and the closed heat pump drying system is operated to slowly heat up and condense and dehumidify; if the dry-bulb temperature Tsg minus the rheumatoid-bulb temperature Thg is set to be less than the fourth temperature d, the first solenoid valve DCF1 is controlled to be opened and the second solenoid valve DCF2 is controlled to be closed, that is, the third heat exchanger 4 is a condenser, so as to maintain the temperature and dehumidify in the drying room.

[0106] When the wet-bulb temperature Tss minus the rheological bulb temperature Thg is set to be less than the second temperature b, it is in the stable temperature holding mode; if the dry-bulb temperature Tsg minus the rheological bulb temperature Thg is set to be less than the fourth temperature d at this time, the third heat exchanger 4 can be controlled to be a condenser, the second heat exchanger 3 to be a condenser, and the first heat exchanger 2 to be an evaporator by controlling the first four-way valve STF1 to be opened, the first solenoid valve DCF1 to be closed, and the second solenoid valve DCF2 to be opened, so as to achieve temperature condensation and dehumidification in the drying room.

[0107] In addition, preferably, the heat pump drying device of this embodiment further includes a pipe temperature sensor 9 , which is disposed on the third heat exchanger 4 and connected to the controller, and is used to detect the pipe temperature Tp of the third heat exchanger 4 .

[0108] The controller receives the piping temperature Tp and is configured to determine the piping temperature Tp when in the heating mode; if the piping temperature Tp is less than or equal to 0°C, the first four-way valve STF1 is controlled to open, the first solenoid valve DCF1 is closed, and the second solenoid valve DCF2 is controlled to open, so that the third heat exchanger 4 is a condenser and runs in the defrost mode.

[0109] Preferably, the value range of the first temperature a is 0~5°C; the value range of the second temperature b is -5~0°C; the value range of the third temperature c is -3~3°C; the value range of the fourth temperature d is -5~2°C.

[0110] Preferably, the value of the first temperature a is 2°C; the value of the second temperature b is -2°C; the value of the third temperature c is 0°C; and the value of the fourth temperature d is -2°C.

[0111] Preferably, the heat pump drying device further includes an outdoor temperature sensor 10, an air supply device 20, and a controllable opening solenoid valve PZF3.

[0112] The air supply device 20 is connected in series with the controllable opening solenoid valve PZF3, and its two ends are connected to the second port 22 and the inlet 12 respectively. The controllable opening solenoid valve PZF3 is connected to the controller, and its action is controlled by the controller to connect or disconnect the air supply device 20 between the second port 22 and the inlet 12.

[0113] The outdoor temperature sensor 10 is arranged on the third heat exchanger 4 and connected to the controller for detecting the outdoor return air temperature Tw; the controller receives the outdoor return air temperature Tw and is configured to determine the outdoor return air temperature Tw in the heating mode;

[0114] When the outdoor return air temperature Tw is greater than 0°C, the controller controls the controllable opening solenoid valve PZF3 to close, that is, the air supply device 20 is not connected between the second port 22 and the inlet 12, and the compressor 1 is not supplied with air;

[0115] When the outdoor return air temperature Tw is less than or equal to 0°C, the controller controls the controllable opening solenoid valve PZF3 to open, connects the air supply device 20 between the second port 22 and the inlet 12, supplies air to the compressor 1, and improves the efficiency of the compressor 1;

[0116] Preferably, the controller can control the opening of the controllable opening solenoid valve PZF3 according to the value of the outdoor return air temperature Tw, and control the amount of air supplied to the compressor 1 by the air supply device 20, so as to make the compressor 1 more efficient.

[0117] Embodiment 5

[0118] Reference Figure 5 and Figure 8 The heat pump drying device of this embodiment includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, a controller, a dry-bulb temperature sensor 7, and a wet-bulb temperature sensor 8; each controllable switch is a second four-way valve STF2.

[0119] The compressor 1 includes an inlet 12 and an outlet 11 ; the first heat exchanger 2 includes a first port 21 and a second port 22 ; the second heat exchanger 3 includes a third port 31 and a fourth port 32 ; the third heat exchanger 4 includes a fifth port 41 and a sixth port 42 .

[0120] The second port 22, the fourth port 32, and the sixth port 42 are connected to each other; the first port 21 is connected to the outlet 11; the third port 31 is connected to the inlet 12; the fifth port 41, the outlet 11, and the inlet 12 are respectively connected to the three ports of the second four-way valve STF2; the fourth ports of the second four-way valve STF2 are closed. When the second four-way valve STF2 is closed, the fifth port 41 is connected to the inlet 12; when the second four-way valve STF2 is opened, the fifth port 41 is connected to the outlet 11.

[0121] The dry-bulb temperature sensor 7 and the wet-bulb temperature sensor 8 are respectively arranged on the second heat exchanger 3 and are respectively connected to the controller for detecting the return air dry-bulb temperature Thg and the return air wet-bulb temperature Thg in the drying room.

[0122] The controller receives the return air dry bulb temperature Thg and the return air wet bulb temperature Thg and is configured to be provided with a set dry bulb temperature Tsg and a first temperature a, and determines the relationship between the return air dry bulb temperature Thg and the set dry bulb temperature Tsg.

[0123] When the set dry bulb temperature Tsg minus the wind dry bulb temperature Thg is greater than or equal to the first temperature a, it is the heating mode, and the controller controls the second four-way valve STF2 to close, then the first heat exchanger 2 is the condenser, the second heat exchanger 3 and the third heat exchanger 4 are the evaporators, and the temperature is quickly raised.

[0124] When the set dry-bulb temperature Tsg minus the return air dry-bulb temperature Thg is less than the first temperature a, it is in the steady temperature mode, that is, the controller controls the second four-way valve STF2 to open, so that the first heat exchanger 2 and the third heat exchanger 4 are condensers, and the second heat exchanger 3 is an evaporator, so as to achieve precise temperature control and condensation dehumidification.

[0125] In addition, preferably, the heat pump drying device of this embodiment further includes a pipe temperature sensor 9 , which is disposed on the third heat exchanger 4 and connected to the controller, and is used to detect the pipe temperature Tp of the third heat exchanger 4 .

[0126] The controller receives the pipe temperature Tp and is configured to determine the pipe temperature Tp when in the heating mode; if the pipe temperature Tp is less than or equal to 0°C, the second four-way valve STF2 is controlled to open, so that the third heat exchanger 4 is a condenser and in the defrosting mode.

[0127] Preferably, the heat pump drying device of this embodiment further includes an electromagnetic expansion valve PZF2, which is connected in series with the third heat exchanger 4 and connected to the controller, and the controller controls its action to connect the third heat exchanger 4 to the circulation system or not to the circulation system. The controller is configured to also set a set wet bulb temperature Tss, a second temperature b, a third temperature c, a fourth temperature d, and determine the relationship between the return air wet bulb temperature Thg and the set wet bulb temperature Tss in the steady temperature mode.

[0128] When the set wet-bulb temperature Tss minus the return air wet-bulb temperature Thg is greater than or equal to the second temperature b, it is in the stable heating mode; if at this time the return air dry-bulb temperature Thg minus the set dry-bulb temperature Tsg is greater than or equal to the third temperature c, the second four-way valve STF2 is controlled to be closed, the electromagnetic expansion valve PZF2 is controlled to be closed, and the compressor 1 is stopped to ensure the temperature requirement; if at this time the return air dry-bulb temperature Thg minus the set dry-bulb temperature Tsg is less than the third temperature c, the second four-way valve STF2 and the electromagnetic expansion valve PZF2 are controlled to be closed, and the compressor 1 is operated, which is a closed heat pump drying system to achieve slow heating and condensation dehumidification.

[0129] When the wet-bulb temperature Tss minus the rheological-bulb temperature Thg is set to be less than the second temperature b, it is in the stable temperature holding mode; if the dry-bulb temperature Tsg minus the rheological-bulb temperature Thg is set to be greater than or equal to the fourth temperature d, the second four-way valve STF2 and the electromagnetic expansion valve PZF2 are controlled to be closed, and the closed heat pump drying system is operated to slowly heat up and condense and dehumidify; if the dry-bulb temperature Tsg minus the rheological-bulb temperature Thg is set to be less than the fourth temperature d, the second four-way valve STF2 and the electromagnetic expansion valve PZF2 are controlled to be opened, that is, the third heat exchanger 4 is a condenser, so as to maintain the temperature in the drying room and condense and dehumidify.

[0130] Preferably, the value range of the first temperature a is 0~5°C; the value range of the second temperature b is -5~0°C; the value range of the third temperature c is -3~3°C; the value range of the fourth temperature d is -5~2°C.

[0131] Preferably, the value of the first temperature a is 2°C; the value of the second temperature b is -2°C; the value of the third temperature c is 0°C; and the value of the fourth temperature d is -2°C.

[0132] Preferably, the heat pump drying device further includes an outdoor temperature sensor 10, an air supply device 20, and a controllable opening solenoid valve PZF3.

[0133] The air supply device 20 is connected in series with the controllable opening solenoid valve PZF3, and its two ends are connected to the second port 22 and the inlet 12 respectively. The controllable opening solenoid valve PZF3 is connected to the controller, and its action is controlled by the controller to connect or disconnect the air supply device 20 between the second port 22 and the inlet 12.

[0134] The outdoor temperature sensor 10 is arranged on the third heat exchanger 4 and connected to the controller for detecting the outdoor return air temperature Tw; the controller receives the outdoor return air temperature Tw and is configured to determine the outdoor return air temperature Tw in the heating mode;

[0135] When the outdoor return air temperature Tw is greater than 0°C, the controller controls the controllable opening solenoid valve PZF3 to close, that is, the air supply device 20 is not connected between the second port 22 and the inlet 12, and the compressor 1 is not supplied with air;

[0136] When the outdoor return air temperature Tw is less than or equal to 0°C, the controller controls the controllable opening solenoid valve PZF3 to open, connects the air supply device 20 between the second port 22 and the inlet 12, supplies air to the compressor 1, and improves the efficiency of the compressor 1;

[0137] Preferably, the controller can control the opening of the controllable opening solenoid valve PZF3 according to the value of the outdoor return air temperature Tw, and control the amount of air supplied to the compressor 1 by the air supply device 20, so as to make the compressor 1 more efficient.

[0138] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0139] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A heat pump drying device, used for drying articles to be dried in a drying room, characterized in that: include: A compressor including an inlet and an outlet; A first heat exchanger, which is arranged in the drying room; A second heat exchanger, which is arranged in the drying room; A third heat exchanger, which is arranged outside the drying room; The first heat exchanger, the second heat exchanger, and the third heat exchanger are connected to the inlet or the outlet through a plurality of controllable switches to form a circulation system; Working modes include: In the heating mode, each of the controllable switches is controlled so that the third heat exchanger is an evaporator; one of the first heat exchanger and the second heat exchanger is an evaporator and the other is a condenser; In a temperature stabilization mode, each of the controllable switches is controlled so that the first heat exchanger or the second heat exchanger is a condenser, the second heat exchanger or the first heat exchanger is an evaporator, or the first heat exchanger or the second heat exchanger and the third heat exchanger are a condenser, and the second heat exchanger or the first heat exchanger is an evaporator; The first heat exchanger includes a first port and a second port; the second heat exchanger includes a third port and a fourth port; the third heat exchanger includes a fifth port and a sixth port; each of the controllable switches is a first four-way valve, a first solenoid valve, and a second solenoid valve; The second port, the fourth port, and the sixth port are connected to each other; the first port, the outlet, the third port, and the inlet are respectively connected to the four ports of the first four-way valve, so that when the first four-way valve is closed, the first port is connected to the outlet, and the third port is connected to the inlet; when the first four-way valve is opened, the first port is connected to the inlet, and the third port is connected to the outlet; the fifth port is connected to the first port through the first solenoid valve, and is connected to the third port through the second solenoid valve; A controller is connected to the compressor, the first four-way valve, the first solenoid valve, and the second solenoid valve respectively; and is configured as follows: When in the temperature rising mode, the first four-way valve is controlled to be closed, and the first solenoid valve and the second solenoid valve are controlled to operate so that the fifth port is connected to the inlet and disconnected from the outlet; When in the temperature stabilization mode, the first four-way valve is controlled to be closed, and the first solenoid valve and the second solenoid valve are controlled to operate so that the fifth port is disconnected from the inlet, disconnected from the outlet, or connected; It also includes a dry-bulb temperature sensor, which is arranged on the first heat exchanger or the second heat exchanger, connected to the controller, and detects the return air dry-bulb temperature; The controller receives the return air dry bulb temperature and is configured to be provided with a set dry bulb temperature and a first temperature, and determines the relationship between the return air dry bulb temperature and the set dry bulb temperature; When the set dry-bulb temperature minus the return air dry-bulb temperature is greater than or equal to the first temperature, the heating mode is set; When the set dry-bulb temperature minus the return air dry-bulb temperature is less than the first temperature, the temperature-stabilizing mode is set; It also includes a wet-bulb temperature sensor, which is arranged on the first heat exchanger or the second heat exchanger, connected to the controller, and detects the return air wet-bulb temperature; The controller receives the return air wet-bulb temperature and is configured to be provided with a set wet-bulb temperature and a second temperature, and determines the relationship between the return air wet-bulb temperature and the set wet-bulb temperature in the temperature-stabilizing mode; If the set wet-bulb temperature minus the return air wet-bulb temperature is greater than or equal to the second temperature, set the temperature to a stable heating mode; If the set wet bulb temperature minus the return air wet bulb temperature is less than the second temperature, the stable temperature holding mode is set; The controller is configured to set a third temperature and determine the relationship between the set dry-bulb temperature and the return air dry-bulb temperature when in the stable heating mode; If the return air dry-bulb temperature minus the set dry-bulb temperature is greater than or equal to the third temperature, the first solenoid valve and the second solenoid valve are controlled to operate so that the fifth port is disconnected from the inlet and the outlet, and the compressor stops running; If the return air dry-bulb temperature minus the set dry-bulb temperature is less than the third temperature, the first solenoid valve and the second solenoid valve are controlled to operate so that the fifth port is disconnected from the inlet and the outlet, and the compressor is operated; The controller is configured to be set with a fourth temperature and to determine the relationship between the set dry-bulb temperature and the return air dry-bulb temperature when in the stable temperature holding mode; If the set dry-bulb temperature minus the return air dry-bulb temperature is greater than or equal to the fourth temperature, the first solenoid valve and the second solenoid valve are controlled to operate so that the fifth port is disconnected from the inlet and the outlet, and the compressor is operated; If the set dry-bulb temperature minus the return air dry-bulb temperature is less than the fourth temperature, the first solenoid valve and the second solenoid valve are controlled to operate so that the fifth port is connected to the outlet and the fifth port is disconnected from the inlet; or the first four-way valve is controlled to be opened, the first solenoid valve is closed, and the second solenoid valve is controlled to be opened so that the third heat exchanger is a condenser, the second heat exchanger is a condenser, and the first heat exchanger is an evaporator, so as to maintain the temperature in the drying room for condensation and dehumidification; Also includes: An outdoor temperature sensor, which is arranged outside the drying room and connected to the controller, is used to detect the outdoor return air temperature; an air supply device connected in series between the second port and the inlet; A controllable opening solenoid valve, which is connected in series with the air supply device and is electrically connected to the controller; The controller receives the outdoor return air temperature and is configured to determine the outdoor return air temperature when the heating mode is on and the fifth port is connected to the inlet and disconnected from the outlet; When the outdoor return air temperature is greater than 0°C, the controllable opening solenoid valve is controlled to close; When the outdoor return air temperature is less than or equal to 0° C., the controllable opening solenoid valve is controlled to open.

2. The heat pump drying device according to claim 1, characterized in that: The first temperature ranges from 0 to 5°C; the second temperature ranges from -5 to 0°C; the third temperature ranges from -3 to 3°C; and the fourth temperature ranges from -5 to 2°C.

3. The heat pump drying device according to claim 2, characterized in that: The first temperature is 2°C; the second temperature is -2°C; the third temperature ranges from 0°C; and the fourth temperature ranges from -2°C.

4. The heat pump drying device according to any one of claims 1 to 3, characterized in that: Also includes: a pipe temperature sensor, which is disposed on the third heat exchanger and connected to the controller to detect the pipe temperature of the third heat exchanger; The controller receives the pipe temperature and is configured to determine the pipe temperature in the heating mode; When the piping temperature is greater than 0°C, the first solenoid valve and the second solenoid valve are controlled to connect the fifth port to the inlet and disconnect it from the outlet; when the piping temperature is less than or equal to 0°C, the first solenoid valve and the second solenoid valve are controlled to connect the fifth port to the outlet and disconnect it from the inlet.

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