阅读说明：本技术 一种热泵烘干机组及其控制方法 (Heat pump drying unit and control method thereof ) 是由 林创辉 张学伟 周伟强 陆家文 覃家海 于 2021-07-21 设计创作，主要内容包括：本发明公开了一种热泵烘干机组及其控制方法,所述热泵烘干机组包括控制装置、空气处理装置和热泵装置,所述空气处理装置包括壳体,所述壳体内沿着进出风方向依次设置有第一热风盘管、蒸发器、风机、电加热器、第二热风盘管,所述第一热风盘管与所述第二热风盘管连接；所述热泵装置与所述蒸发器连接,所述蒸发器用于对空气降温除湿；所述风机、电加热器和热泵装置分别与所述控制装置电性连接；本申请公开的热泵烘干机组,通过第一热风盘管回收回风的热量,第二热风盘管采用所回收的热量对空气进行加温,提高了能源利用率；第二热风盘管与所述电加热器配合工作,可提高热泵烘干机组的烘干效率和烘干效果,从而提高用户的使用体验。(The invention discloses a heat pump drying unit and a control method thereof, wherein the heat pump drying unit comprises a control device, an air treatment device and a heat pump device, the air treatment device comprises a shell, a first hot air coil, an evaporator, a fan, an electric heater and a second hot air coil are sequentially arranged in the shell along the air inlet and outlet directions, and the first hot air coil is connected with the second hot air coil; the heat pump device is connected with the evaporator, and the evaporator is used for cooling and dehumidifying air; the fan, the electric heater and the heat pump device are respectively electrically connected with the control device; according to the heat pump drying unit, the heat of return air is recovered through the first hot air coil pipe, and the second hot air coil pipe heats air by adopting the recovered heat, so that the energy utilization rate is improved; the hot-blast coil pipe of second with electric heater cooperation work can improve heat pump drying unit's drying efficiency and stoving effect to improve user's use and experience.)

1. A heat pump drying unit is characterized by comprising a control device, an air treatment device and a heat pump device, wherein the air treatment device comprises a shell, a first hot air coil, an evaporator, a fan, an electric heater and a second hot air coil are sequentially arranged in the shell along the air inlet and outlet directions, and the first hot air coil is connected with the second hot air coil; the heat pump device is connected with the evaporator, and the evaporator is used for cooling and dehumidifying air; the fan, the electric heater and the heat pump device are respectively electrically connected with the control device.

2. The heat pump dryer group of claim 1, further comprising a first temperature sensor and a first humidity sensor disposed on the air inlet side of the housing, and a second temperature sensor and a second humidity sensor disposed on the air outlet side of the housing; the first temperature sensor, the first humidity sensor, the second temperature sensor and the second humidity sensor are respectively electrically connected with the control device.

3. The heat pump dryer group of claim 2, wherein the heat pump device comprises a compressor, a heat exchanger, a drying filter, an expansion valve and a gas-liquid separator; the output end of the compressor is connected with the input end of the heat exchanger, the output end of the heat exchanger is connected with the input end of the drying filter, the output end of the drying filter is connected with the input end of the expansion valve, the output end of the expansion valve is connected with one end of the evaporator, the other end of the evaporator is connected with the input end of the gas-liquid separator, and the output end of the gas-liquid separator is connected with the input end of the compressor.

4. The heat pump dryer group of claim 3, further comprising a regulating valve and a bypass valve, and an auxiliary surface cooler and an oil cooler disposed in the housing; the auxiliary surface air cooler is arranged on the air outlet side of the evaporator, and the regulating valve is connected with an interface of the auxiliary surface air cooler; the oil cooler is arranged on the air outlet side of the second hot air coil, an inlet pipe of the oil cooler is connected with an oil way outlet of the compressor, and an outlet pipe of the oil cooler is connected with an oil way inlet of the compressor; one end of the bypass valve is connected with the inlet pipe, and the other end of the bypass valve is connected with the outlet pipe; the regulating valve and the bypass valve are respectively electrically connected with the control device.

5. The heat pump dryer group of claim 3, wherein said heat pump device further comprises a first on-off valve, a first throttling device, a second on-off valve and a second throttling device; one end of the first on-off valve is connected with the low-pressure liquid spraying port of the compressor through the first throttling device, and the other end of the first on-off valve is respectively connected with the output end of the drying filter and the input end of the expansion valve; one end of the second on-off valve is connected with the middle liquid spraying port of the compressor through the second throttling device, and the other end of the second on-off valve is connected with the output end of the drying filter and the input end of the expansion valve respectively.

6. The heat pump drying unit according to claim 3, wherein the heat pump device further comprises a high-pressure protector, an exhaust pressure sensor, a low-pressure protector and a suction pressure sensor, which are electrically connected to the control device, respectively, and the high-pressure protector and the exhaust pressure sensor are disposed on a connection pipeline between the compressor and the heat exchanger; the low-pressure protector and the air suction pressure sensor are arranged on a connecting pipeline of the gas-liquid separator and the compressor.

7. The heat pump dryer set according to claim 2, wherein a check valve is disposed on a connection pipeline between the first hot air coil and the second hot air coil.

8. A control method of a heat pump dryer group, characterized in that the control method is used for realizing the operation control of the heat pump dryer group according to any one of claims 2 to 7, and the control method comprises the steps of:

the control device obtains a real-time air inlet temperature T10 fed back by the first temperature sensor, a real-time air inlet humidity phi 10 fed back by the first humidity sensor, a real-time air outlet temperature T20 fed back by the second temperature sensor and a real-time air outlet humidity phi 20 fed back by the second humidity sensor, and compares the magnitudes between T10 and a preset air inlet temperature T11 and a first temperature precision delta T11, between phi 10 and a preset air inlet humidity phi 11 and a humidity precision delta phi 11, and between T20 and a preset air outlet temperature T21 and a second temperature precision delta T21 respectively;

and the control device adjusts the working states of the heat pump device and the fan according to the comparison result.

9. The control method of the heat pump drying unit according to claim 8, wherein the heat pump device comprises a compressor, an expansion valve, a gas-liquid separator, a first on-off valve, a second on-off valve and an exhaust temperature sensor, and an oil cooler is further disposed in the housing and is disposed on an air outlet side of the second hot air coil; the compressor, the expansion valve and the gas-liquid separator are connected end to end; the compressor is connected with the oil cooler through a bypass valve, and the first on-off valve is arranged on a connecting pipeline between a low-pressure liquid spraying opening of the compressor and the expansion valve; the second on-off valve is arranged on a connecting pipeline between a middle liquid spraying port of the compressor and the expansion valve; the control method further comprises the steps of:

the control device acquires an exhaust temperature value T30 fed back by the exhaust temperature sensor in real time, and compares the value between T30 and a preset first action temperature T31, a preset first reset temperature T32, a preset second action temperature T33 and a preset second reset temperature T34 respectively;

and the control device adjusts the on-off states of the first on-off valve and the second on-off valve according to the comparison result.

10. The control method of the heat pump dryer group according to claim 9, further comprising the steps of:

the control device acquires an exhaust temperature value T30 fed back by the exhaust temperature sensor in real time, and compares the exhaust temperature value T30 with a preset third action temperature T35 and a preset third reset temperature T36 respectively;

the control device adjusts the on-off state of the bypass valve according to the comparison result.

Technical Field

The invention relates to the technical field of heat pump drying, in particular to a heat pump drying unit and a control method thereof.

Background

The existing single hot air drying heat pump unit does not have a heat recovery function, and for objects with high drying difficulty, on the premise that heat in return air cannot be effectively recovered, direct cooling and dehumidification are realized, so that a large amount of energy is consumed, and the working energy consumption of the hot air drying heat pump unit is greatly improved; in addition, the problem that the drying efficiency is low, the drying time is long and the power consumption is serious exists by simply depending on hot air for drying, and if the drying time is too short, the problem that the actual drying effect cannot reach the drying target effect exists for the articles which are difficult to dry.

It is seen that improvements and enhancements to the prior art are needed.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a heat pump drying unit which can effectively recover the heat of return air and heat the air by using the heat of the return air, thereby improving the energy utilization rate.

In order to achieve the purpose, the invention adopts the following technical scheme:

a heat pump drying unit comprises a control device, an air treatment device and a heat pump device, wherein the air treatment device comprises a shell, a first hot air coil, an evaporator, a fan, an electric heater and a second hot air coil are sequentially arranged in the shell along the air inlet and outlet directions, and the first hot air coil is connected with the second hot air coil; the heat pump device is connected with the evaporator, and the evaporator is used for cooling and dehumidifying air; the fan, the electric heater and the heat pump device are respectively electrically connected with the control device.

The heat pump drying unit also comprises a first temperature sensor and a first humidity sensor which are arranged on the air inlet side of the shell, and a second temperature sensor and a second humidity sensor which are arranged on the air outlet side of the shell; the first temperature sensor, the first humidity sensor, the second temperature sensor and the second humidity sensor are respectively electrically connected with the control device.

In the heat pump drying unit, the heat pump device comprises a compressor, a heat exchanger, a drying filter, an expansion valve and a gas-liquid separator; the output end of the compressor is connected with the input end of the heat exchanger, the output end of the heat exchanger is connected with the input end of the drying filter, the output end of the drying filter is connected with the input end of the expansion valve, the output end of the expansion valve is connected with one end of the evaporator, the other end of the evaporator is connected with the input end of the gas-liquid separator, and the output end of the gas-liquid separator is connected with the input end of the compressor.

The heat pump drying unit also comprises a regulating valve, a bypass valve, an auxiliary surface cooler and an oil cooler which are arranged in the shell; the auxiliary surface air cooler is arranged on the air outlet side of the evaporator, and the regulating valve is connected with an interface of the auxiliary surface air cooler; the oil cooler is arranged on the air outlet side of the second hot air coil, an inlet pipe of the oil cooler is connected with an oil way outlet of the compressor, and an outlet pipe of the oil cooler is connected with an oil way inlet of the compressor; one end of the bypass valve is connected with the inlet pipe, and the other end of the bypass valve is connected with the outlet pipe; the regulating valve and the bypass valve are respectively electrically connected with the control device.

In the heat pump drying unit, the heat pump device further comprises a first on-off valve, a first throttling device, a second on-off valve and a second throttling device; one end of the first on-off valve is connected with the low-pressure liquid spraying port of the compressor through the first throttling device, and the other end of the first on-off valve is respectively connected with the output end of the drying filter and the input end of the expansion valve; one end of the second on-off valve is connected with the middle liquid spraying port of the compressor through the second throttling device, and the other end of the second on-off valve is connected with the output end of the drying filter and the input end of the expansion valve respectively.

In the heat pump drying unit, the heat pump device further comprises a high-pressure protector, an exhaust pressure sensor, a low-pressure protector and an air suction pressure sensor which are respectively electrically connected with the control device, and the high-pressure protector and the exhaust pressure sensor are arranged on a connecting pipeline of the compressor and the heat exchanger; the low-pressure protector and the air suction pressure sensor are arranged on a connecting pipeline of the gas-liquid separator and the compressor.

In the heat pump drying unit, a check valve is arranged on a connecting pipeline of the first hot air coil and the second hot air coil.

The invention also correspondingly provides a control method of the heat pump drying unit, which is used for realizing the working control of the heat pump drying unit, and the control method comprises the following steps:

the control device obtains a real-time air inlet temperature T10 fed back by the first temperature sensor, a real-time air inlet humidity phi 10 fed back by the first humidity sensor, a real-time air outlet temperature T20 fed back by the second temperature sensor and a real-time air outlet humidity phi 20 fed back by the second humidity sensor, and compares the magnitudes between T10 and a preset air inlet temperature T11 and a first temperature precision delta T11, between phi 10 and a preset air inlet humidity phi 11 and a humidity precision delta phi 11, and between T20 and a preset air outlet temperature T21 and a second temperature precision delta T21 respectively;

and the control device adjusts the working states of the heat pump device and the fan according to the comparison result.

In the control method of the heat pump drying unit, the heat pump device comprises a compressor, an expansion valve, a gas-liquid separator, a first on-off valve, a second on-off valve and an exhaust temperature sensor, and an oil cooler is also arranged in the shell and arranged on the air outlet side of the second hot air coil; the compressor, the expansion valve and the gas-liquid separator are connected end to end; the compressor is connected with the oil cooler through a bypass valve, and the first on-off valve is arranged on a connecting pipeline between a low-pressure liquid spraying opening of the compressor and the expansion valve; the second on-off valve is arranged on a connecting pipeline between a middle liquid spraying port of the compressor and the expansion valve; the control method further comprises the steps of:

the control device acquires an exhaust temperature value T30 fed back by the exhaust temperature sensor in real time, and compares the value between T30 and a preset first action temperature T31, a preset first reset temperature T32, a preset second action temperature T33 and a preset second reset temperature T34 respectively;

and the control device adjusts the on-off states of the first on-off valve and the second on-off valve according to the comparison result.

In the control method of the heat pump drying unit, the control method further comprises the following steps:

the control device acquires an exhaust temperature value T30 fed back by the exhaust temperature sensor in real time, and compares the exhaust temperature value T30 with a preset third action temperature T35 and a preset third reset temperature T36 respectively;

the control device adjusts the on-off state of the bypass valve according to the comparison result.

Has the advantages that:

the invention provides a heat pump drying unit, which has the following advantages:

(1) the first hot air coil pipe is used for recovering the heat of return air, and the second hot air coil pipe is used for heating air by adopting the recovered heat, so that the energy utilization rate is improved;

(2) the second hot air coil pipe and the electric heater work in a matched mode, so that the drying efficiency and the drying effect of the heat pump drying unit can be improved, and the use experience of a user is improved;

(3) the first hot air coil is arranged on the air inlet side of the evaporator, the first hot air pipe pre-cools the return air, and energy consumption required by the evaporator during cooling and dehumidifying the air can be reduced, so that working energy consumption of the heat pump drying unit is reduced, and working effect of the heat pump drying unit is improved.

Drawings

Fig. 1 is a schematic structural diagram of a heat pump drying unit provided by the invention;

fig. 2 is a system structure diagram of a heat pump drying unit provided by the invention;

FIG. 3 is a first logic flow diagram of a control method provided by the present invention;

FIG. 4 is a second logic flow diagram of the control method provided by the present invention;

fig. 5 is a third logic flow diagram of the control method provided by the present invention.

Description of the main element symbols: 1-control device, 2-shell, 21-first hot air coil, 22-evaporator, 23-blower, 24-electric heater, 25-second hot air coil, 26-auxiliary surface cooler, 261-regulating valve, 27-oil cooler, 28-air filter, 29-check valve, 31-compressor, 32-heat exchanger, 33-drying filter, 34-expansion valve, 35-gas-liquid separator, 36-bypass valve, 371-first on-off valve, 372-first throttle device, 373-second on-off valve, 374-second throttle device, 381-high pressure protector, 382-exhaust pressure sensor, 391-low pressure protector, 392-suction pressure sensor, 41-first temperature sensor, 22-electric heater, 42-first humidity sensor, 43-second temperature sensor, 44-second humidity sensor, 45-exhaust temperature sensor, 5-display operation panel.

Detailed Description

The invention provides a heat pump drying unit and a control method thereof, and in order to make the purpose, technical scheme and effect of the invention clearer and clearer, the invention is further described in detail below by referring to the attached drawings and embodiments.

In the description of the present invention, it is to be understood that the terms "mounted," "connected," and the like are to be interpreted broadly, and those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Referring to fig. 1 and 2, the present invention provides a heat pump drying unit, including a control device 1, an air processing device and a heat pump device, where the air processing device includes a casing 2, a first hot air coil 21, an evaporator 22, a fan 23, an electric heater 24, and a second hot air coil 25 are sequentially arranged in the casing 2 along an air inlet and outlet direction, and the first hot air coil 21 is connected with the second hot air coil 25; the heat pump device is connected with the evaporator 22, and the evaporator 22 is used for cooling and dehumidifying air; the fan 23, the electric heater 24 and the heat pump device are respectively electrically connected with the control device 1; in one embodiment, the control device 1 adjusts the rotational speed of the fan 23 through a fan regulator.

According to the heat pump drying unit, return air is input into the shell 2 from the air inlet formed in the shell 2 and passes through the first hot air coil 21, the first hot air coil 21 pre-cools the return air, the heat of the return air is effectively recovered, the pre-cooled return air is further cooled and dehumidified in the evaporator 22, and the energy consumption required by the evaporator 22 is reduced due to the fact that the return air is cooled once, so that the working energy consumption of the heat pump drying unit is reduced; the return air after temperature reduction and dehumidification is heated through the electric heater 24 and the second hot air coil 25 in sequence, the second hot air coil 25 is connected with the first hot air coil 21, the air is heated by utilizing the heat recovered by the first hot air coil 21, the energy utilization rate is improved, and the electric heater 24 is matched with the second hot air coil 25, so that the drying temperature can be improved, the drying efficiency and the drying effect are improved, and the use experience of a user is indirectly improved; under the action of the fan 23, the heated air is output from an air outlet formed on the housing 2.

In one embodiment, referring to fig. 1, an air filter 28 is disposed on an air inlet side of the housing 2, the air filter 28 is located on the air inlet side of the first hot air coil 21, and the air filter 28 filters return air, so as to improve the cleanliness of the air output by the heat pump drying unit.

Further, referring to fig. 1 and fig. 2, the heat pump dryer group further includes a first temperature sensor 41 and a first humidity sensor 42 disposed on the air inlet side of the casing 2, and a second temperature sensor 43 and a second humidity sensor 44 disposed on the air outlet side of the casing 2; the first temperature sensor 41, the first humidity sensor 42, the second temperature sensor 43, and the second humidity sensor 44 are respectively electrically connected to the control device 1, and the control device 1 can adjust the working state of the heat pump device according to real-time data fed back by the first temperature sensor 41, the first humidity sensor 42, the second temperature sensor 43, and the second humidity sensor 44.

Further, referring to fig. 1 and 2, the heat pump apparatus includes a compressor 31, a heat exchanger 32, a dry filter 33, an expansion valve 34, and a gas-liquid separator 35; the output end of the compressor 31 is connected with the input end of the heat exchanger 32, the output end of the heat exchanger 32 is connected with the input end of the dry filter 33, the output end of the dry filter 33 is connected with the input end of the expansion valve 34, the output end of the expansion valve 34 is connected with one end of the evaporator 22, the other end of the evaporator 22 is connected with the input end of the gas-liquid separator 35, and the output end of the gas-liquid separator 35 is connected with the input end of the compressor 31; the high-temperature refrigerant output by the compressor 31 is cooled in the heat exchanger 32, and then sequentially passes through the drying filter 33 and the expansion valve 34 and enters the evaporator 22; the refrigerant having absorbed heat in the evaporator 22 returns to the compressor 31 through the gas-liquid separator 35, and the refrigerant circulates.

Further, referring to fig. 1 and 2, the heat pump dryer group further includes a regulating valve 261 and a bypass valve 36, and an auxiliary surface cooler 26 and an oil cooler 27 disposed in the casing 2; the auxiliary surface cooler 26 is arranged on the air outlet side of the evaporator 22, and the regulating valve 261 is connected with an interface of the auxiliary surface cooler 26; the oil cooler 27 is arranged on the air outlet side of the second hot air coil 25, an inlet pipe of the oil cooler 27 is connected with an oil path outlet of the compressor 31, and an outlet pipe of the oil cooler 27 is connected with an oil path inlet of the compressor 31; one end of the bypass valve 36 is connected with the inlet pipe, and the other end is connected with the outlet pipe; the regulating valve 261 and the bypass valve 36 are respectively electrically connected with the control device 1; the auxiliary surface cooler 26 is arranged to cool the air, so that the energy consumption required by the evaporator 22 for cooling and dehumidifying the air can be further reduced, and the working energy consumption of the heat pump drying unit can be further reduced; the oil cooler 27 is provided to heat air by high-temperature lubricating oil output from the compressor 31, so that the energy utilization rate is improved while the temperature of the lubricating oil is reduced.

Further, referring to fig. 1 and fig. 2, the heat pump apparatus further includes a first on-off valve 371, a first throttling device 372, a second on-off valve 373, and a second throttling device 374; one end of the first on-off valve 371 is connected with the low-pressure liquid spraying port of the compressor 31 through the first throttling device 372, and the other end of the first on-off valve 371 is connected with the output end of the dry filter 33 and the input end of the expansion valve 34 respectively; one end of the second on-off valve 373 is connected to the middle liquid injection port of the compressor 31 through the second throttling device 374, and the other end of the second on-off valve 373 is connected to the output end of the dry filter 33 and the input end of the expansion valve 34, respectively; the first on-off valve 371 and the second on-off valve 373 are arranged, the compressor 31 can output high-temperature refrigerant to the evaporator 22, the problem of ice blockage of the evaporator 22 is avoided, and the stability and the safety of the heat pump drying unit during operation are improved.

Further, referring to fig. 1 and fig. 2, the heat pump apparatus further includes a high-pressure protector 381, an exhaust pressure sensor 382, a low-pressure protector 391 and an intake pressure sensor 392, which are electrically connected to the control apparatus 1, respectively, and the high-pressure protector 381 and the exhaust pressure sensor 382 are disposed on a connection pipeline between the compressor 31 and the heat exchanger 32; the low-pressure protector 391 and the suction pressure sensor 392 are provided in a connection line between the gas-liquid separator 35 and the compressor 31.

Further, referring to fig. 1, the heat pump apparatus further includes an exhaust temperature sensor 45 electrically connected to the control apparatus 1, the exhaust temperature sensor 45 is configured to detect an exhaust temperature of the compressor 31, and the exhaust temperature sensor 45 is disposed on a connection pipeline between the compressor 31 and the high voltage protector 381; the control device 1 may adjust the operating states of the first on-off valve 371, the second on-off valve 373, and the bypass valve 36 based on real-time data fed back from the exhaust temperature sensor 45.

Further, referring to fig. 1 and fig. 2, a check valve 29 is disposed on a connection pipeline between the first hot air coil 21 and the second hot air coil 25; the check valve 29 is arranged, so that liquid can be prevented from flowing backwards, and the safety degree of the heat pump drying unit during working is improved.

Referring to fig. 3 to 5, the present invention further provides a control method of a heat pump dryer group correspondingly, where the control method is used to implement the operation control of the heat pump dryer group, and the control method includes the steps of:

s100, the control device 1 obtains a real-time air inlet temperature T10 fed back by the first temperature sensor 41, a real-time air inlet humidity phi 10 fed back by the first humidity sensor 42, a real-time air outlet temperature T20 fed back by the second temperature sensor 43 and a real-time air outlet humidity phi 20 fed back by the second humidity sensor 44, and compares the T10 with a preset air inlet temperature T11, a first temperature precision delta T11, the phi 10 with a preset air inlet humidity phi 11, a humidity precision delta phi 11 and the magnitude of the T20 with a preset air outlet temperature T21 and a second temperature precision delta T21 respectively; in one embodiment, the heat pump dryer group further includes a display operation panel 5 electrically connected to the control device 1, and a user or a worker may input the values of T11, Δ T11, Φ 11, Δ Φ 11, T21, and Δ T21 in the control device 1 in advance according to the working conditions, the working environment, and the like of the heat pump dryer group through the display operation panel 5.

S200, the control device 1 adjusts the working states of the heat pump device and the fan 23 according to the comparison result; specifically, in an embodiment, referring to fig. 3, the step S200 specifically includes the following steps:

s210, if phi 11-delta phi 11 is not less than phi 10 and not more than phi 11+ delta phi 11, the control device 1 controls the compressor 31 to keep the original working state; in addition, when the auxiliary surface cooler 26 is arranged in the shell 2, if phi 11-delta phi 11 is less than or equal to phi 10 and less than or equal to phi 11+ delta phi 11, the control device 1 controls the compressor 31 and the regulating valve 261 to keep the working state unchanged.

S220, if phi 10 is larger than phi 11+ delta phi 11, the control device 1 controls the compressor 31 to load; further, when the auxiliary surface cooler 26 is provided in the casing 2, if Φ 10 > Φ 11+ Δ Φ 11, the control device 1 controls the compressor 31 and the regulating valve 261 to be loaded.

S230, if the phi 10 is smaller than the phi 11 to the delta phi 11, the control device 1 controls the compressor 31 to unload; in addition, when the auxiliary surface cooler 26 is provided in the casing 2, if Φ 10 < Φ 11- Δ Φ 11, the control device 1 controls the compressor 31 and the adjustment valve 261 to unload to adjust the dehumidification effect of the evaporator 22.

S240, if T11-delta T11 is not less than T10 is not less than T11+ delta T11, the control device 1 controls the fan 23 and the compressor 31 to keep the original working state;

s250, if T10 is greater than T11+ delta T11, the control device 1 firstly controls the fan 23 to load, and when the fan 23 is loaded to be consistent with the preset maximum load value of the fan 23, the control device 1 controls the compressor 31 to unload;

and S260, if T10 is less than T11-delta T11, the control device 1 firstly controls the compressor 31 to load, and when the compressor 31 is loaded to be consistent with the preset maximum loading value of the compressor 31, the control device 1 controls the fan 23 to unload so as to adjust the heating effect of the heat pump drying unit.

S270, if the T21-delta T21 is not less than T20 is not less than T21+ delta T21, the control device 1 controls the compressor 31 to keep the original working state;

s280, if T20 is more than T21+ delta T21, the control device 1 controls the compressor 31 to unload;

and S290, if T20 is less than T21-delta T21, the control device 1 controls the loading of the compressor 31 to adjust the heating effect of the heat pump drying unit.

According to the control method disclosed by the application, the control device 1 can adjust the working states of the compressor 31, the fan 23 and the regulating valve 261 according to the real-time data fed back by the first temperature sensor 41, the first humidity sensor 42 and the second temperature sensor 43, so that the stability and the reliability of the heat pump drying unit during working are improved.

Further, referring to fig. 2 and 4, the heat pump device includes a compressor 31, an expansion valve 34, a gas-liquid separator 35, a first on-off valve 371, a second on-off valve 373, and an exhaust temperature sensor 45, an oil cooler 27 is further disposed in the housing 2, and the oil cooler 27 is disposed on an air outlet side of the second hot air coil 25; the compressor 31, the expansion valve 34 and the gas-liquid separator 35 are connected end to end; the compressor 31 is connected to the oil cooler 27 through a bypass valve 36, and the first on-off valve 371 is disposed on a connection line between a low-pressure liquid injection port of the compressor 31 and the expansion valve 34; the second on-off valve 373 is disposed on a connection pipeline between the intermediate liquid injection port of the compressor 31 and the expansion valve 34; the control method further comprises the steps of:

s310, the control device 1 obtains an exhaust temperature value T30 fed back by the exhaust temperature sensor 45 in real time, and compares the value of the T30 with a preset first action temperature T31, a preset first reset temperature T32, a preset second action temperature T33 and a preset second reset temperature T34 respectively;

s320, the control device 1 adjusts the on-off states of the first on-off valve 371 and the second on-off valve 373 according to the comparison result, specifically, referring to fig. 4, in an embodiment, the step S320 specifically includes the steps of:

s321, if T30 is not less than T31, the control device 1 controls the first on-off valve 371 to be switched on;

s322, if T30 is less than T32, the control device 1 controls the first on-off valve 371 to be disconnected;

s323, if T30 is not less than T33, the control device 1 controls the second cut-off valve 373 to be switched on;

s324, if T30 < T34, the control device 1 controls the second shutoff valve 373 to open.

The user or the worker can set the sizes of T31, T32, T33 and T34 in the control device 1 in advance through the display operation panel 5; the control device 1 adjusts the on-off states of the first on-off valve 371 and the second on-off valve 373 according to the comparison results of T30 and T31, T32, T33 and T34, so that the problem of ice blockage of the evaporator 22 can be avoided, the working temperature of the compressor 31 can be prevented from being too high, and the safety degree of the heat pump dryer set during working is improved.

Further, referring to fig. 5, the control method further includes the steps of:

s410, the control device 1 obtains an exhaust temperature value T30 fed back by the exhaust temperature sensor 45 in real time, and compares the value between T30 and a preset third action temperature T35 and a third reset temperature T36 respectively;

s420, the control device 1 adjusts the on-off state of the bypass valve 36 according to the comparison result; in an embodiment, referring to fig. 5, the step S420 specifically includes the steps of:

s421, if T30 is less than or equal to T35, the control device 1 controls the bypass valve 36 to be switched on;

s422, if T30 is greater than T36, the control device 1 controls the bypass valve 36 to be opened.

The user or the worker can set the sizes of T35 and T36 in the control device 1 in advance through the implementation operation panel; the control device 1 adjusts the on-off state of the bypass valve 36 according to the comparison result of the T30 and the T35 and the T36, can fully utilize the high-temperature lubricating oil of the compressor 31 to heat air, improve the energy utilization rate, avoid overhigh working temperature of the compressor 31 and improve the safety degree of the heat pump drying unit during working.

It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the protective scope of the present invention.