Drying apparatus, and control method and control device therefor

Abstract

The present disclosure provides a drying device and a control method and control device thereof, and relates to the technical field of heat pumps. The drying device comprises a compressor, a condenser, a first expansion valve, an auxiliary heat exchanger, a second expansion valve, an evaporator and a gas-liquid separator arranged in sequence along the flow direction of refrigerant, and a control device, wherein the control device is configured to realize drying control through temperature rise control and dehumidification control by adjusting the first expansion valve and the second expansion valve.

Description

Technical Field

[0001] This disclosure relates to the field of heat pump technology, and in particular to a drying equipment and its control method and control device. Background Technology

[0002] Air source heat pump drying equipment includes open-loop and closed-loop drying systems. Open-loop drying systems offer superior dehumidification performance, but their energy efficiency is low due to direct air exchange with the environment. Closed-loop drying systems are more environmentally friendly and efficient, but they often rely on four-way reversing valves for operation. Summary of the Invention

[0003] The drying equipment provided in this embodiment includes a compressor, a condenser, a first expansion valve, an auxiliary heat exchanger, a second expansion valve, an evaporator, and a gas-liquid separator arranged sequentially along the refrigerant flow direction, as well as a control device. The control device is configured to achieve drying control by adjusting the first and second expansion valves to control temperature rise and dehumidification. Thus, a drying equipment is realized based on the expansion valves.

[0004] This disclosure provides a drying apparatus in some embodiments, including:

[0005] The compressor, condenser, first expansion valve, auxiliary heat exchanger, second expansion valve, evaporator, and gas-liquid separator, along with the control device, are arranged sequentially along the refrigerant flow direction.

[0006] The control device is configured to control heating and dehumidification by adjusting the first expansion valve and the second expansion valve to achieve drying control.

[0007] In some embodiments, the device further includes: a first temperature sensor disposed on the inlet side of the auxiliary heat exchanger, and a second temperature sensor disposed on the outlet side of the auxiliary heat exchanger. The control device is configured to adjust the first expansion valve according to the current second temperature difference during temperature rise control, wherein the second temperature difference is the difference between the second temperature detected by the second temperature sensor and the first temperature detected by the first temperature sensor.

[0008] In some embodiments, the control device is configured to:

[0009] When the current second temperature difference is within a first range, a first adjustment value is determined by comparing the current second temperature difference with the midpoint between the lower and upper limits of the second temperature difference. The first expansion valve is then controlled to increase the first adjustment value based on its current opening. The first range is either greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference; or...

[0010] When the current second temperature difference is within the second range, the first expansion valve is controlled to maintain its current opening degree. The second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference.

[0011] In some embodiments, the control device is configured to use the difference between the current second temperature difference and the intermediate value between the lower limit and the upper limit of the second temperature difference as the first adjustment value.

[0012] In some embodiments, the device further includes: a third temperature sensor disposed on the outlet side of the condenser, and a pressure sensor disposed on the inlet side of the condenser. The control device is configured to: adjust the second expansion valve according to the current first temperature difference when the current second temperature difference is in a third range and the first expansion valve remains inactive for a first duration. The third range is located within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and the first value, and less than or equal to the difference between the upper limit of the second temperature difference and the first value. The first temperature difference is the difference between the temperature obtained by converting the pressure detected by the pressure sensor and the third temperature detected by the third temperature sensor.

[0013] In some embodiments, the control device is configured to:

[0014] When the current first temperature difference falls within the fourth range, a second adjustment value is determined by comparing the current first temperature difference with the midpoint between the lower and upper limits of the first temperature difference. The second expansion valve is then controlled to increase its opening by this second adjustment value. The fourth range is defined as either greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference; or...

[0015] When the current first temperature difference is within the fifth range, the second expansion valve is controlled to maintain its current opening degree, wherein the fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference.

[0016] In some embodiments, the control device is configured to use the difference between the current first temperature difference and the intermediate value between the lower limit and the upper limit of the first temperature difference as the second adjustment value.

[0017] In some embodiments, the control device is configured to: control the second expansion valve to maintain its current opening when the current second temperature difference is within a sixth range, wherein the sixth range is within the second range and is less than the sum of the lower limit of the second temperature difference and the second value or greater than the difference between the upper limit of the second temperature difference and the second value, and the second value is less than the first value.

[0018] In some embodiments, the control device is configured to control the second expansion valve to maintain an upper limit of its opening.

[0019] In some embodiments, the device further includes: a fourth temperature sensor disposed on the inlet side of the evaporator, and a fifth temperature sensor disposed on the outlet side of the evaporator. The control device is configured to adjust the second expansion valve according to the current third temperature difference during dehumidification control, wherein the third temperature difference is the difference between the fifth temperature detected by the fifth temperature sensor and the fourth temperature detected by the fourth temperature sensor.

[0020] In some embodiments, the control device is configured to:

[0021] When the current third temperature difference falls within the seventh range, a third adjustment value is determined by comparing the current third temperature difference with the midpoint between the lower and upper limits of the third temperature difference. The second expansion valve is then controlled to increase the third adjustment value based on its current opening. The seventh range is either greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference; or...

[0022] When the current third temperature difference is within the eighth range, the second expansion valve is controlled to maintain its current opening degree, wherein the eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference.

[0023] In some embodiments, the control device is configured to use the difference between the current third temperature difference and the intermediate value between the lower limit and the upper limit of the third temperature difference as the third adjustment value.

[0024] In some embodiments, the control device is configured to control the first expansion valve to maintain an upper limit of its opening.

[0025] In some embodiments, the device further includes: a first fan disposed in the condenser, a second fan disposed in the auxiliary heat exchanger, and a third fan disposed in the evaporator. The control device is configured to: control the rotational speed of the first fan and the second fan to be higher than the rotational speed of the third fan during heating control; or, control the rotational speed of the third fan and the second fan to be higher than the rotational speed of the first fan during dehumidification control.

[0026] This disclosure provides a control method for a drying device, the drying device comprising: a compressor, a condenser, a first expansion valve, an auxiliary heat exchanger, a second expansion valve, an evaporator, and a gas-liquid separator arranged sequentially along the refrigerant flow direction, and a control device, the method comprising: performing temperature control and dehumidification control by adjusting the first expansion valve and the second expansion valve to achieve drying control.

[0027] In some embodiments, the drying equipment further includes: a first temperature sensor disposed on the inlet side of the auxiliary heat exchanger, and a second temperature sensor disposed on the outlet side of the auxiliary heat exchanger. The temperature control includes: adjusting the first expansion valve according to the current second temperature difference, wherein the second temperature difference is the difference between the second temperature detected by the second temperature sensor and the first temperature detected by the first temperature sensor.

[0028] In some embodiments, adjusting the first expansion valve according to the current second temperature difference includes: when the current second temperature difference is within a first range, determining a first adjustment value by comparing the current second temperature difference with the midpoint between the lower limit and the upper limit of the second temperature difference, and controlling the first expansion valve to increase the first adjustment value based on the current opening, wherein the first range is greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference; or, when the current second temperature difference is within a second range, controlling the first expansion valve to maintain the current opening, wherein the second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference.

[0029] In some embodiments, determining the first adjustment value includes: taking the difference between the current second temperature difference and the median value between the lower limit and the upper limit of the second temperature difference as the first adjustment value.

[0030] In some embodiments, the drying equipment further includes: a third temperature sensor disposed on the outlet side of the condenser, and a pressure sensor disposed on the inlet side of the condenser. The temperature control includes: adjusting the second expansion valve according to the current first temperature difference when the current second temperature difference is in a third range and the first expansion valve remains inactive for a first duration. The third range is located within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and the first value, and less than or equal to the difference between the upper limit of the second temperature difference and the first value. The first temperature difference is the difference between the temperature obtained by converting the pressure detected by the pressure sensor and the third temperature detected by the third temperature sensor.

[0031] In some embodiments, adjusting the second expansion valve according to the current first temperature difference includes: when the current first temperature difference is in a fourth range, determining a second adjustment value by comparing the current first temperature difference with the midpoint between the lower limit and the upper limit of the first temperature difference, and controlling the second expansion valve to increase the second adjustment value based on the current opening, wherein the fourth range is greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference; or, when the current first temperature difference is in a fifth range, controlling the second expansion valve to maintain the current opening, wherein the fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference.

[0032] In some embodiments, determining the second adjustment value includes using the difference between the current first temperature difference and the median value between the lower limit and the upper limit of the first temperature difference as the second adjustment value.

[0033] In some embodiments, the temperature control includes: when the current second temperature difference is within a sixth range, controlling the second expansion valve to maintain its current opening, wherein the sixth range is within the second range and is less than the sum of the lower limit of the second temperature difference and the second value or greater than the difference between the upper limit of the second temperature difference and the second value, and the second value is less than the first value.

[0034] In some embodiments, the temperature control further includes controlling the second expansion valve to maintain its upper limit of opening.

[0035] In some embodiments, the drying equipment further includes: a fourth temperature sensor disposed on the inlet side of the evaporator, and a fifth temperature sensor disposed on the outlet side of the evaporator. The dehumidification control includes: adjusting the second expansion valve according to the current third temperature difference, wherein the third temperature difference is the difference between the fifth temperature detected by the fifth temperature sensor and the fourth temperature detected by the fourth temperature sensor.

[0036] In some embodiments, adjusting the second expansion valve according to the current third temperature difference includes: when the current third temperature difference is in a seventh range, determining a third adjustment value by comparing the current third temperature difference with the midpoint between the lower limit and the upper limit of the third temperature difference, and controlling the second expansion valve to increase the third adjustment value based on the current opening, wherein the seventh range is greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference; or, when the current third temperature difference is in an eighth range, controlling the second expansion valve to maintain the current opening, wherein the eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference.

[0037] In some embodiments, determining the third adjustment value includes using the difference between the current third temperature difference and the median value between the lower limit and the upper limit of the third temperature difference as the third adjustment value.

[0038] In some embodiments, the dehumidification control further includes controlling the first expansion valve to maintain its upper limit of opening.

[0039] In some embodiments, the drying equipment further includes: a first fan disposed in the condenser, a second fan disposed in the auxiliary heat exchanger, and a third fan disposed in the evaporator; the temperature control further includes: controlling the rotational speed of the first fan and the second fan to be higher than the rotational speed of the third fan; or, the dehumidification control further includes: controlling the rotational speed of the third fan and the second fan to be higher than the rotational speed of the first fan.

[0040] Some embodiments of this disclosure provide a control device for a drying apparatus, including: a memory; and a processor coupled to the memory, the processor being configured to execute a control method for the drying apparatus based on instructions stored in the memory.

[0041] This disclosure provides a control device for a drying equipment, comprising: a module for executing a control method for the drying equipment.

[0042] Some embodiments of this disclosure provide a non-transitory computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of a control method for a drying apparatus. Attached Figure Description

[0043] The accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. This disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings.

[0044] Obviously, the accompanying drawings described below are merely some embodiments of this disclosure. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0045] Figure 1 A schematic diagram of a controlled system according to some embodiments of the present disclosure is shown.

[0046] Figure 2 A schematic diagram illustrating a control method for a drying apparatus according to some embodiments of the present disclosure is shown.

[0047] Figure 3 A schematic diagram of the structure of the control device of a drying apparatus according to some embodiments of the present disclosure is shown.

[0048] Figure 4 A schematic diagram of the structure of the control device of a drying apparatus according to some embodiments of the present disclosure is shown. Detailed Implementation

[0049] The technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings.

[0050] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this disclosure.

[0051] Those skilled in the art will understand that, unless otherwise specified, the terms "first," "second," etc., in the embodiments of this disclosure are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0052] Figure 1 A schematic diagram of a drying apparatus according to some embodiments of the present disclosure is shown. This drying apparatus is a closed-loop drying apparatus.

[0053] like Figure 1 As shown, the drying equipment in this embodiment includes: a compressor 1, a condenser 2, a first expansion valve 3, an auxiliary heat exchanger 4, a second expansion valve 5, an evaporator 6, and a gas-liquid separator 7 arranged sequentially along the refrigerant flow direction, and a control device 8; depending on control requirements, it may also include a first temperature sensor 10 disposed on the inlet side of the auxiliary heat exchanger 4, and a second temperature sensor 11 disposed on the outlet side of the auxiliary heat exchanger 4; depending on control requirements, it may also include a third temperature sensor 9 disposed on the outlet side of the condenser 2, and a pressure sensor 14 disposed on the inlet side of the condenser 2 (or, the exhaust side of the compressor 1); depending on control requirements, it may also include a fourth temperature sensor 12 disposed on the inlet side of the evaporator 6, and a fifth temperature sensor 13 disposed on the outlet side of the evaporator 6; depending on control requirements, it may also include a first fan 15 disposed on the condenser 2, a second fan 16 disposed on the auxiliary heat exchanger 4, and a third fan 17 disposed on the evaporator 6. The first expansion valve 3 is, for example, a first electronic expansion valve, and the second expansion valve 5 is, for example, a second electronic expansion valve. The third temperature sensor 9 is also called a liquid line temperature sensor. Pressure sensor 14 is, for example, a sensor suitable for detecting high pressure on the exhaust side of compressor 1.

[0054] The first temperature difference (denoted as t△1) is the difference between the temperature obtained by converting the pressure detected by the pressure sensor 14 (denoted as tc) and the third temperature detected by the third temperature sensor 9 (denoted as tl), i.e., t△1 = tc - tl.

[0055] The second temperature difference (denoted as t△2) is the difference between the second temperature detected by the second temperature sensor 11 (denoted as tof) and the first temperature detected by the first temperature sensor 10 (denoted as tif), i.e., t△2 = tof - tif.

[0056] The third temperature difference (denoted as t△3) is the difference between the fifth temperature (denoted as toe) detected by the fifth temperature sensor 13 and the fourth temperature (denoted as tie) detected by the fourth temperature sensor 12, i.e., t△3 = toe - tie.

[0057] During the preparation phase of operation, the drying equipment enters a self-test phase after receiving a control command. If the pressure or temperature exceeds the preset range, it is not allowed to start. After the test is completed, the fan and expansion valve perform a self-test. If there are no abnormalities, it is allowed to be put into operation.

[0058] During the initialization phase of the drying equipment, the compressor, expansion valves, and fans are put into operation with initial settings. After the preset initialization time, if there are no abnormalities in the unit, the drying control phase begins.

[0059] In some embodiments, the control device 8 is configured to perform heating and dehumidification control by adjusting the first expansion valve 3 and the second expansion valve 5 to achieve drying control. Thus, a drying device is realized based on the expansion valves. During the drying control process, heating control can be performed first to fully release the moisture in the object being dried, and then dehumidification control can be performed to remove the released moisture in a timely manner. Depending on the object being dried and the drying requirements, the heating and dehumidification control can be performed alternately once or multiple times.

[0060] The temperature control process is described below.

[0061] In some embodiments, the control device 8 is configured to adjust the first expansion valve 3 based on the current second temperature difference during temperature rise control. Thus, in temperature rise mode, based on the current second temperature difference, it is determined whether the refrigerant circulation volume of the unit needs optimization, and the first expansion valve 3 is adjusted accordingly to optimize the refrigerant circulation volume of the unit and improve the temperature rise control effect during the drying process.

[0062] In some embodiments, the control device 8 is configured to, when the current second temperature difference is within a first range, indicate that the refrigerant circulation of the unit is not optimal. It determines a first adjustment value by comparing the current second temperature difference (denoted as T△2) with the intermediate value between the lower limit (denoted as d, e.g., 4) and the upper limit (denoted as c, e.g., 10) of the second temperature difference. The difference between the current second temperature difference and the intermediate value between the lower and upper limits of the second temperature difference can be used as the first adjustment value, i.e., [T△2 - (c + d) / 2]. The first expansion valve 3 is controlled to increase the first adjustment value based on its current opening (denoted as B1), i.e., B1 += [T△2 - (c + d) / 2]. The first range is greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference, i.e., c < T△2 or T△2 < d. Therefore, in the heating mode, by controlling the first expansion valve 3, the refrigerant circulation of the unit is optimized, improving the heating control effect during the drying process.

[0063] In some embodiments, the control device 8 is configured to, when the current second temperature difference is within a second range, indicate that the refrigerant circulation volume of the unit is reasonable and there is no need to optimize the refrigerant circulation volume at this time, and control the first expansion valve 3 to maintain its current opening. The second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference, i.e., c≥T△2≥d. The first expansion valve 3 needs to be maintained for a preset time after adjustment, such as 10 seconds. In this embodiment, the control device 8 is configured to control the second expansion valve 5 to maintain its upper limit opening.

[0064] By adjusting the first expansion valve 3, the refrigerant circulation volume can be optimized, making the unit operate more reliably. Based on this, further adjustments to the second expansion valve 5 can further optimize the refrigerant circulation volume, enabling the unit to operate in a highly efficient state.

[0065] In some embodiments, the control device 8 is configured to, when the current second temperature difference is within a third range and the first expansion valve 3 remains inactive for a first duration (e.g., 60 seconds), indicate that the refrigerant circulation volume of the unit can be further optimized, and adjust the second expansion valve 5 according to the current first temperature difference. The third range is located within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and a first value (e.g., 2), and less than or equal to the difference between the upper limit of the second temperature difference and the first value, i.e., c-2 > T△2 > d+2. This further optimizes the refrigerant circulation volume of the unit by controlling the second expansion valve 5, improving the temperature control effect during the drying process.

[0066] In some embodiments, the control device 8 is configured to indicate that the refrigerant circulation volume of the unit can be further optimized when the current first temperature difference is within a fourth range. A second adjustment value is determined by comparing the current first temperature difference (denoted as T△1) with the intermediate value between the lower limit (denoted as b) and the upper limit (denoted as a) of the first temperature difference. The difference between the current first temperature difference and the intermediate value between the lower limit and the upper limit of the first temperature difference can be used as the second adjustment value, i.e., [T△1 - (a + b) / 2]. The second expansion valve 5 is controlled to increase the second adjustment value based on the current opening degree (denoted as B2), i.e., B2 += [T△1 - (a + b) / 2]. The fourth range is greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference, i.e., b > T△1 or T△1 > a. Thus, by controlling the second expansion valve 5, the refrigerant circulation volume of the unit is further optimized, and the temperature control effect during the drying process is improved.

[0067] In some embodiments, the control device 8 is configured to indicate that the refrigerant circulation rate of the unit is at the boundary of the optimal state when the current first temperature difference is within a fifth range, and adjustment is not recommended. The control device 8 then controls the second expansion valve 5 to maintain its current opening. The fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference, i.e., a≥T△1≥b. The second expansion valve 5 must be maintained for a preset time after adjustment, for example, 10 seconds.

[0068] In some embodiments, the control device 8 is configured to indicate that the refrigerant circulation volume of the unit is at the boundary of the optimal state when the current second temperature difference is in the sixth range, and it is not recommended to adjust it. The control device 8 controls the second expansion valve 5 to maintain the current opening. The sixth range is located within the second range and is less than the sum of the lower limit of the second temperature difference and the second value (e.g., 1) or greater than the difference between the upper limit of the second temperature difference and the second value. The second value is less than the first value, i.e., d+1 > T△2 or T△2 > c-1.

[0069] By setting the first value, the third range is located in the middle region of the second range; conversely, by setting the second value, the sixth range is located in the boundary region of the second range. Therefore, those skilled in the art will understand that the specific values ​​of the first and second values ​​are not limited to the examples listed above.

[0070] In the process of temperature control, in addition to temperature control by adjusting the first expansion valve 3 and the second expansion valve 5 as described in the above embodiments, the fans can also be controlled. The speed of the first fan 15 and the speed of the second fan 16 can be controlled to be higher than the speed of the third fan 17. For example, the first fan 15 and the second fan 16 can be controlled to run at high speed, while the third fan 17 can be controlled to standby and not operate, thereby further improving the temperature control effect.

[0071] The dehumidification control process is described below.

[0072] In some embodiments, the control device 8 is configured to adjust the second expansion valve 5 based on the current third temperature difference during dehumidification control. Thus, in dehumidification mode, based on the current third temperature difference, it is determined whether the refrigerant circulation volume of the unit needs optimization, and the second expansion valve 5 is adjusted accordingly to optimize the refrigerant circulation volume of the unit and improve the dehumidification control effect during the drying process.

[0073] In some embodiments, the control device 8 is configured to indicate that the refrigerant circulation of the unit can be optimized when the current third temperature difference is within the seventh range. A third adjustment value is determined by comparing the current third temperature difference (denoted as T△3) with the intermediate value between the lower limit (denoted as f, e.g., 4) and the upper limit (denoted as e, e.g., 10) of the third temperature difference. The difference between the current third temperature difference and the intermediate value between the lower and upper limits of the third temperature difference can be used as the third adjustment value, i.e., [T△3 - (e + f) / 2]. The second expansion valve 5 is controlled to increase the third adjustment value based on the current opening, i.e., B2 + = [T△3 - (e + f) / 2]. The seventh range is greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference, i.e., e < T△3 or T△3 < f. Therefore, in dehumidification mode, by controlling the second expansion valve 5, the refrigerant circulation of the unit is optimized, improving the dehumidification control effect during the drying process.

[0074] In some embodiments, the control device 8 is configured to, when the current third temperature difference is within an eighth range, indicate that the refrigerant circulation volume of the unit does not need to be optimized at this time, and control the second expansion valve 5 to maintain its current opening. The eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference, i.e., e≥T△3≥f. The second expansion valve 5 needs to be maintained for a preset time after adjustment, for example, 10 seconds. In this embodiment, the control device 8 is configured to control the first expansion valve 3 to maintain its upper limit opening.

[0075] In the dehumidification control process, in addition to dehumidification control by adjusting the first expansion valve 3 and the second expansion valve 5 as described in the above embodiments, the fans can also be controlled. The speed of the third fan 17 and the second fan 16 can be controlled to be higher than the speed of the first fan 15. For example, the first fan 15 can be controlled to run at a low speed, while the third fan 17 and the second fan 16 can be controlled to run at a high speed, thereby further improving the dehumidification effect.

[0076] In some embodiments, the upper / lower limits a, b, c, d, e, and f in the foregoing embodiments depend on different refrigerants and the heating capacity of the unit. These values ​​can be determined through matching tests to ensure unit operational reliability while simultaneously measuring optimal energy efficiency. Therefore, those skilled in the art will understand that the specific values ​​of a, b, c, d, e, and f are not limited to the examples listed above.

[0077] The drying equipment provided in this embodiment includes a compressor, a condenser, a first expansion valve, an auxiliary heat exchanger, a second expansion valve, an evaporator, and a gas-liquid separator arranged sequentially along the refrigerant flow direction, as well as a control device. The control device is configured to achieve drying control by adjusting the first expansion valve and the second expansion valve to control heating and dehumidification.

[0078] During the heating control process, the heat exchanger needs a larger evaporation area. By controlling the expansion valve, the heat exchanger is assisted to function as an evaporator, thus providing a larger evaporation area during heating. During the dehumidification control process, the heat exchanger needs a larger condensation area. By controlling the expansion valve, the heat exchanger is assisted to function as a condenser, with both heat exchangers and condensers dissipating heat together, thus providing a larger condensation area during dehumidification. Therefore, during the drying control process, the expansion valve allows for flexible switching between heating and dehumidification control, and the actual evaporation and condensation areas of the unit can also be flexibly varied. The (closed-loop) drying equipment of this embodiment, through its simple structure, solves the business requirements of a larger evaporation area during heating and a larger condensation area during dehumidification.

[0079] Furthermore, the three heat exchangers are connected in series, with the condenser and evaporator working continuously, and the auxiliary heat exchanger also switching between condensation and evaporation and working continuously, so there is no flow accumulation and the reliability is higher.

[0080] Figure 2 A schematic diagram illustrating a control method for a drying apparatus according to some embodiments of the present disclosure is shown.

[0081] like Figure 2 As shown, the control method of the drying equipment in this embodiment includes: temperature control (step S21) and dehumidification control (step S22) by adjusting the first expansion valve 3 and the second expansion valve 5 to achieve drying control.

[0082] In some embodiments, step S21 of performing temperature control includes: in step S211, adjusting the first expansion valve 3 according to the current second temperature difference, wherein the second temperature difference is the difference between the second temperature detected by the second temperature sensor 11 and the first temperature detected by the first temperature sensor 10.

[0083] In some embodiments, step S211, adjusting the first expansion valve 3 according to the current second temperature difference, includes: in step S211a, when the current second temperature difference is within a first range, determining a first adjustment value by comparing the current second temperature difference with the median value between the lower limit and the upper limit of the second temperature difference, using the difference between the current second temperature difference and the median value between the lower limit and the upper limit of the second temperature difference as the first adjustment value, and controlling the first expansion valve 3 to increase the first adjustment value based on the current opening, wherein the first range is greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference; or, in step S211b, when the current second temperature difference is within a second range, controlling the first expansion valve 3 to maintain the current opening, wherein the second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference.

[0084] In some embodiments, step S21 for temperature control further includes: in step S212, when the current second temperature difference is within a third range and the first expansion valve 3 remains inactive for a first duration, adjusting the second expansion valve 5 according to the current first temperature difference, wherein the third range is within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and the first value and less than or equal to the difference between the upper limit of the second temperature difference and the first value, and the first temperature difference is the difference between the temperature obtained by pressure conversion detected by the pressure sensor 14 and the third temperature detected by the third temperature sensor 9.

[0085] In some embodiments, step S212 of adjusting the second expansion valve 5 according to the current first temperature difference includes: in step S212a, when the current first temperature difference is in a fourth range, determining a second adjustment value by comparing the current first temperature difference with the midpoint between the lower limit and the upper limit of the first temperature difference, taking the difference between the current first temperature difference and the midpoint between the lower limit and the upper limit of the first temperature difference as the second adjustment value, and controlling the second expansion valve 5 to increase the second adjustment value based on the current opening, wherein the fourth range is greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference; or, in step S212b, when the current first temperature difference is in a fifth range, controlling the second expansion valve 5 to maintain the current opening, wherein the fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference.

[0086] In some embodiments, the temperature control in step S21 further includes: in step S213, when the current second temperature difference is in the sixth range, controlling the second expansion valve 5 to maintain the current opening, wherein the sixth range is located within the second range and is less than the sum of the lower limit of the second temperature difference and the second value or greater than the difference between the upper limit of the second temperature difference and the second value, and the second value is less than the first value.

[0087] In some embodiments, step S21 for temperature control further includes: when performing steps S211a and S211b, performing step S214 to control the second expansion valve 5 to maintain the upper limit of its opening.

[0088] In some embodiments, step S21, which involves controlling the temperature rise, further includes: in step S215, controlling the rotational speed of the first fan 15 and the second fan 16 to be higher than the rotational speed of the third fan 17. Step 213 can be executed simultaneously with steps 211 and 212.

[0089] In some embodiments, the dehumidification control in step S22 includes: in step S221, adjusting the second expansion valve 5 according to the current third temperature difference, wherein the third temperature difference is the difference between the fifth temperature detected by the fifth temperature sensor 13 and the fourth temperature detected by the fourth temperature sensor 12.

[0090] In some embodiments, step S221, adjusting the second expansion valve 5 according to the current third temperature difference, includes: in step S221a, when the current third temperature difference is in a seventh range, determining a third adjustment value by comparing the current third temperature difference with the midpoint between the lower limit and the upper limit of the third temperature difference, using the difference between the current third temperature difference and the midpoint between the lower limit and the upper limit of the third temperature difference as the third adjustment value, and controlling the second expansion valve 5 to increase the third adjustment value based on the current opening, wherein the seventh range is greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference; or, in step S221b, when the current third temperature difference is in an eighth range, controlling the second expansion valve 5 to maintain the current opening, wherein the eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference.

[0091] In some embodiments, the dehumidification control in step S22 further includes: in step S222, controlling the first expansion valve 3 to maintain its upper limit of opening. Steps S222 and S221 can be executed simultaneously.

[0092] In some embodiments, the dehumidification control in step S22 includes: in step S223, controlling the rotational speed of the third fan 17 and the second fan 16 to be higher than the rotational speed of the first fan 15. Step S223 can be executed simultaneously with steps S221 and S222.

[0093] During the heating control process, the heat exchanger needs a larger evaporation area. By controlling the expansion valve, the auxiliary heat exchanger functions as an evaporator, thus providing a larger evaporation area during heating. Similarly, during dehumidification control, the heat exchanger needs a larger condensation area. Again, by controlling the expansion valve, the auxiliary heat exchanger functions as a condenser, working together with the condenser to dissipate heat, thus providing a larger condensation area during dehumidification. Therefore, during the drying control process, the expansion valve allows for flexible switching between heating and dehumidification control, and the actual evaporation and condensation areas of the unit can also be flexibly adjusted.

[0094] Figure 3 A schematic diagram of the structure of the control device of a drying apparatus according to some embodiments of the present disclosure is shown.

[0095] like Figure 3As shown, the control device 300 of the drying equipment in this embodiment includes a memory 310 and a processor 320 coupled to the memory 310. The processor 320 is configured to execute the methods in any of the foregoing embodiments based on instructions stored in the memory 310.

[0096] The control device 300 of the drying equipment may also include an input / output interface 330, a network interface 340, a storage interface 350, etc. These interfaces 330, 340, 350, as well as the memory 310 and the processor 320, can be connected, for example, via a bus 360.

[0097] The memory 310 may include, for example, system memory, fixed non-volatile storage media, etc. The system memory stores, for example, the operating system, application programs, boot loader, and other programs.

[0098] The processor 320 can be implemented using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates, or transistors, or other discrete hardware components.

[0099] The input / output interface 330 provides a connection interface for input / output devices such as monitors, mice, keyboards, and touchscreens. The network interface 340 provides a connection interface for various networked devices. The storage interface 350 provides a connection interface for external storage devices such as SD cards and USB flash drives. The bus 360 can use any bus architecture from various bus structures. For example, bus architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, and Peripheral Component Interconnect (PCI) bus.

[0100] Figure 4 A schematic diagram of the structure of the control device of a drying apparatus according to some embodiments of the present disclosure is shown.

[0101] like Figure 4 As shown, the control device 400 of the drying equipment in this embodiment is configured to control the temperature rise and dehumidification by adjusting the first expansion valve 3 and the second expansion valve 5, so as to achieve drying control.

[0102] The control device 400 of the drying equipment includes a heating control module 410 and a dehumidification control module 420.

[0103] The heating control module 410 includes a first heating control unit 411, configured to adjust the first expansion valve 3 according to the current second temperature difference, wherein the second temperature difference is the difference between the second temperature detected by the second temperature sensor 11 and the first temperature detected by the first temperature sensor 10.

[0104] The first temperature control unit 411 is configured to, when the current second temperature difference is within a first range, determine a first adjustment value by comparing the current second temperature difference with the midpoint between the lower and upper limits of the second temperature difference, and use the difference between the current second temperature difference and the midpoint between the lower and upper limits of the second temperature difference as the first adjustment value, and control the first expansion valve 3 to increase the first adjustment value based on the current opening degree, wherein the first range is greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference; or, when the current second temperature difference is within a second range, control the first expansion valve 3 to maintain the current opening degree, wherein the second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference.

[0105] The first heating control unit 411 is also configured to control the second expansion valve 5 to maintain the upper limit of its opening.

[0106] The temperature control module 410 includes a second temperature control unit 412, configured to adjust the second expansion valve 5 according to the current first temperature difference when the current second temperature difference is in a third range and the first expansion valve 3 remains inactive for a first duration. The third range is located within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and the first value, and less than or equal to the difference between the upper limit of the second temperature difference and the first value. The first temperature difference is the difference between the temperature obtained by converting the pressure detected by the pressure sensor 14 and the third temperature detected by the third temperature sensor 9.

[0107] The second temperature control unit 412 is configured to, when the current first temperature difference is in a fourth range, determine a second adjustment value by comparing the current first temperature difference with the midpoint between the lower and upper limits of the first temperature difference, and use the difference between the current first temperature difference and the midpoint between the lower and upper limits of the first temperature difference as the second adjustment value, and control the second expansion valve 5 to increase the second adjustment value based on the current opening degree, wherein the fourth range is greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference; or, when the current first temperature difference is in a fifth range, control the second expansion valve 5 to maintain the current opening degree, wherein the fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference.

[0108] The heating control module 410 includes a third heating control unit 413, configured to control the second expansion valve 5 to maintain its current opening when the current second temperature difference is within a sixth range, wherein the sixth range is within the second range and is less than the sum of the lower limit of the second temperature difference and the second value or greater than the difference between the upper limit of the second temperature difference and the second value, and the second value is less than the first value.

[0109] The heating control module 410 includes a fourth heating control unit 414, configured to control the speed of the first fan 15 and the speed of the second fan 16 to be higher than the speed of the third fan 17. Step 213 can be executed simultaneously with steps 211 and 212.

[0110] The dehumidification control module 420 is configured to adjust the second expansion valve 5 according to the current third temperature difference, wherein the third temperature difference is the difference between the fifth temperature detected by the fifth temperature sensor 13 and the fourth temperature detected by the fourth temperature sensor 12.

[0111] The dehumidification control module 420 includes a first dehumidification control unit 421, configured to, when the current third temperature difference is in a seventh range, determine a third adjustment value by comparing the current third temperature difference with the midpoint between the lower and upper limits of the third temperature difference, and use the difference between the current third temperature difference and the midpoint between the lower and upper limits of the third temperature difference as the third adjustment value, and control the second expansion valve 5 to increase the third adjustment value based on the current opening degree, wherein the seventh range is greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference; or, when the current third temperature difference is in an eighth range, control the second expansion valve 5 to maintain the current opening degree, wherein the eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference.

[0112] The dehumidification control module 420 includes a second dehumidification control unit 422, which is configured to control the first expansion valve 3 to maintain the upper limit of its opening.

[0113] The dehumidification control module 420 includes a third dehumidification control unit 423, which is configured to control the speed of the third fan 17 and the second fan 16 to be higher than the speed of the first fan 15.

[0114] This disclosure provides a non-transitory computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a control method for a drying device.

[0115] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more non-transitory computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer program code.

[0116] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0117] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0118] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0119] The above description is only a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A drying device, characterized in that, include: The compressor (1), condenser (2), first expansion valve (3), auxiliary heat exchanger (4), second expansion valve (5), evaporator (6) and gas-liquid separator (7), and control device (8) are arranged sequentially along the refrigerant flow direction. The control device (8) is configured to perform heating control and dehumidification control by adjusting the first expansion valve (3) and the second expansion valve (5) to achieve drying control, wherein: during the drying control process, heating control is performed first, and then dehumidification control is performed. During the heating control process, the auxiliary heat exchanger (4) works as an evaporator to expand the evaporation area; during the dehumidification control process, the auxiliary heat exchanger (4) works as a condenser, and the auxiliary heat exchanger (4) dissipates heat together with the condenser (2) to expand the condensation area.

2. The drying equipment according to claim 1, characterized in that, Also includes: A first temperature sensor (10) is installed on the inlet side of the auxiliary heat exchanger (4). A second temperature sensor (11) is installed on the outlet side of the auxiliary heat exchanger (4). The control device (8) is configured to adjust the first expansion valve (3) according to the current second temperature difference during temperature control. The second temperature difference is the difference between the second temperature detected by the second temperature sensor (11) and the first temperature detected by the first temperature sensor (10).

3. The drying equipment according to claim 2, characterized in that, The control device (8) is configured to: When the current second temperature difference is within the first range, the first adjustment value is determined by comparing the current second temperature difference with the midpoint between the lower limit and the upper limit of the second temperature difference, and the first expansion valve (3) is controlled to increase the first adjustment value based on the current opening. The first range is greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference. or, When the current second temperature difference is within the second range, the first expansion valve (3) is controlled to maintain its current opening degree, where the second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference.

4. The drying equipment according to claim 3, characterized in that, The control device (8) is configured to use the difference between the current second temperature difference and the intermediate value between the lower limit and the upper limit of the second temperature difference as the first adjustment value.

5. The drying equipment according to claim 3, characterized in that, Also includes: A third temperature sensor (9) is installed on the outlet side of the condenser (2). A pressure sensor (14) is installed on the inlet side of the condenser (2). The control device (8) is configured to: adjust the second expansion valve (5) according to the current first temperature difference when the current second temperature difference is within the third range and the first expansion valve (3) remains inactive for a first duration. The third range is located within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and the first value, and less than or equal to the difference between the upper limit of the second temperature difference and the first value. The first temperature difference is the difference between the temperature obtained by pressure conversion detected by the pressure sensor (14) and the third temperature detected by the third temperature sensor (9).

6. The drying equipment according to claim 5, characterized in that, The control device (8) is configured to: When the current first temperature difference is in the fourth range, the second adjustment value is determined by comparing the current first temperature difference with the midpoint between the lower limit and the upper limit of the first temperature difference, and the second expansion valve (5) is controlled to increase the second adjustment value based on the current opening. The fourth range is greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference. or, When the current first temperature difference is within the fifth range, the second expansion valve (5) is controlled to maintain the current opening degree, wherein the fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference.

7. The drying equipment according to claim 6, characterized in that, The control device (8) is configured to use the difference between the current first temperature difference and the intermediate value between the lower limit and the upper limit of the first temperature difference as the second adjustment value.

8. The drying equipment according to claim 5, characterized in that, The control device (8) is configured to: when the current second temperature difference is within the sixth range, control the second expansion valve (5) to maintain its current opening. Wherein, the sixth range is located within the second range and is less than the sum of the lower limit of the second temperature difference and the second value or greater than the difference between the upper limit of the second temperature difference and the second value, and the second value is less than the first value.

9. The drying equipment according to claim 3 or 4, characterized in that, The control device (8) is configured to control the second expansion valve (5) to maintain the upper limit of its opening.

10. The drying equipment according to any one of claims 1-8, characterized in that, Also includes: A fourth temperature sensor (12) is installed on the inlet side of the evaporator (6). A fifth temperature sensor (13) is installed on the outlet side of the evaporator (6). The control device (8) is configured to adjust the second expansion valve (5) according to the current third temperature difference during dehumidification control. The third temperature difference is the difference between the fifth temperature detected by the fifth temperature sensor (13) and the fourth temperature detected by the fourth temperature sensor (12).

11. The drying equipment according to claim 10, characterized in that, The control device (8) is configured to: When the current third temperature difference is within the seventh range, the third adjustment value is determined by comparing the current third temperature difference with the midpoint between the lower limit and the upper limit of the third temperature difference, and the second expansion valve (5) is controlled to increase the third adjustment value based on the current opening. The seventh range is greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference. or, When the current third temperature difference is within the eighth range, the second expansion valve (5) is controlled to maintain the current opening degree, wherein the eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference.

12. The drying equipment according to claim 11, characterized in that, The control device (8) is configured to use the difference between the current third temperature difference and the intermediate value between the lower limit and the upper limit of the third temperature difference as the third adjustment value.

13. The drying equipment according to claim 10, characterized in that, The control device (8) is configured to control the first expansion valve (3) to maintain the upper limit of its opening.

14. The drying equipment according to any one of claims 1-8, characterized in that, Also includes: The first fan (15) is installed in the condenser (2). The second fan (16) is installed in the auxiliary heat exchanger (4). A third fan (17) is installed on the evaporator (6). The control device (8) is configured to: control the rotation speed of the first fan (15) and the rotation speed of the second fan (16) to be higher than the rotation speed of the third fan (17) during heating control; or, control the rotation speed of the third fan (17) and the second fan (16) to be higher than the rotation speed of the first fan (15) during dehumidification control.

15. A control method for a drying device, characterized in that, The drying equipment includes: a compressor (1), a condenser (2), a first expansion valve (3), an auxiliary heat exchanger (4), a second expansion valve (5), an evaporator (6), and a gas-liquid separator (7) arranged sequentially along the refrigerant flow direction, as well as a control device (8). The method includes: adjusting the first expansion valve (3) and the second expansion valve (5) to achieve drying control, wherein: during the drying control process, heating control is performed first, followed by dehumidification control; during the heating control process, the auxiliary heat exchanger (4) works as an evaporator to expand the evaporation area; during the dehumidification control process, the auxiliary heat exchanger (4) works as a condenser, and the auxiliary heat exchanger (4) dissipates heat together with the condenser (2) to expand the condensation area.

16. The method according to claim 15, characterized in that, The drying equipment further includes: a first temperature sensor (10) installed on the inlet side of the auxiliary heat exchanger (4), and a second temperature sensor (11) installed on the outlet side of the auxiliary heat exchanger (4). The heating control includes adjusting the first expansion valve (3) according to the current second temperature difference, wherein the second temperature difference is the difference between the second temperature detected by the second temperature sensor (11) and the first temperature detected by the first temperature sensor (10).

17. The method according to claim 16, characterized in that, Adjusting the first expansion valve (3) based on the current second temperature difference includes: When the current second temperature difference is within the first range, a first adjustment value is determined by comparing the current second temperature difference with the midpoint between the lower and upper limits of the second temperature difference. The first expansion valve (3) is then controlled to increase the first adjustment value based on the current opening degree. The first range is greater than the upper limit of the second temperature difference or less than the lower limit of the second temperature difference; or, When the current second temperature difference is within the second range, the first expansion valve (3) is controlled to maintain its current opening degree, where the second range is greater than or equal to the lower limit of the second temperature difference and less than or equal to the upper limit of the second temperature difference.

18. The method according to claim 17, characterized in that, Determining the first adjustment value includes: taking the difference between the current second temperature difference and the median value between the lower limit and the upper limit of the second temperature difference as the first adjustment value.

19. The method according to claim 17, characterized in that, The drying equipment also includes: a third temperature sensor (9) installed on the outlet side of the condenser (2) and a pressure sensor (14) installed on the inlet side of the condenser (2). The temperature control includes: when the current second temperature difference is within the third range and the first expansion valve (3) remains inactive for a first duration, adjusting the second expansion valve (5) according to the current first temperature difference. The third range is located within the second range and is greater than or equal to the sum of the lower limit of the second temperature difference and the first value, and less than or equal to the difference between the upper limit of the second temperature difference and the first value. The first temperature difference is the difference between the temperature obtained by pressure conversion detected by the pressure sensor (14) and the third temperature detected by the third temperature sensor (9).

20. The method according to claim 19, characterized in that, Adjusting the second expansion valve (5) based on the current first temperature difference includes: When the current first temperature difference is within the fourth range, a second adjustment value is determined by comparing the current first temperature difference with the midpoint between the lower and upper limits of the first temperature difference. The second expansion valve (5) is then controlled to increase the second adjustment value based on its current opening. The fourth range is either greater than the upper limit of the first temperature difference or less than the lower limit of the first temperature difference; or... When the current first temperature difference is within the fifth range, the second expansion valve (5) is controlled to maintain the current opening degree, wherein the fifth range is greater than or equal to the lower limit of the first temperature difference and less than or equal to the upper limit of the first temperature difference.

21. The method according to claim 20, characterized in that, Determining the second adjustment value includes: taking the difference between the current first temperature difference and the median value between the lower limit and the upper limit of the first temperature difference as the second adjustment value.

22. The method according to claim 19, characterized in that, The temperature control includes: when the current second temperature difference is within the sixth range, controlling the second expansion valve (5) to maintain its current opening. Wherein, the sixth range is located within the second range and is less than the sum of the lower limit of the second temperature difference and the second value or greater than the difference between the upper limit of the second temperature difference and the second value, and the second value is less than the first value.

23. The method according to claim 17 or 18, characterized in that, The temperature control also includes controlling the second expansion valve (5) to maintain the upper limit of its opening.

24. The method according to any one of claims 15-22, characterized in that, The drying equipment also includes: a fourth temperature sensor (12) disposed on the inlet side of the evaporator (6), and a fifth temperature sensor (13) disposed on the outlet side of the evaporator (6). The dehumidification control includes adjusting the second expansion valve (5) according to the current third temperature difference, wherein the third temperature difference is the difference between the fifth temperature detected by the fifth temperature sensor (13) and the fourth temperature detected by the fourth temperature sensor (12).

25. The method according to claim 24, characterized in that, Adjusting the second expansion valve (5) based on the current third temperature difference includes: When the current third temperature difference is within the seventh range, a third adjustment value is determined by comparing the current third temperature difference with the midpoint between the lower and upper limits of the third temperature difference. The second expansion valve (5) is then controlled to increase the third adjustment value based on the current opening degree. The seventh range is greater than the upper limit of the third temperature difference or less than the lower limit of the third temperature difference; or... When the current third temperature difference is within the eighth range, the second expansion valve (5) is controlled to maintain the current opening degree, wherein the eighth range is greater than or equal to the lower limit of the third temperature difference and less than or equal to the upper limit of the third temperature difference.

26. The method according to claim 25, characterized in that, Determining the third adjustment value includes: taking the difference between the current third temperature difference and the median value between the lower limit and the upper limit of the third temperature difference as the third adjustment value.

27. The method according to claim 24, characterized in that, The dehumidification control also includes: controlling the first expansion valve (3) to maintain the upper limit of its opening.

28. The method according to any one of claims 15-22, characterized in that, The drying equipment further includes: a first fan (15) installed in the condenser (2), a second fan (16) installed in the auxiliary heat exchanger (4), and a third fan (17) installed in the evaporator (6). The temperature control also includes: controlling the rotation speed of the first fan (15) and the second fan (16) to be higher than the rotation speed of the third fan (17); or, The dehumidification control also includes controlling the rotation speed of the third fan (17) and the second fan (16) to be higher than the rotation speed of the first fan (15).

29. A control device for a drying equipment, comprising: Memory; as well as A processor coupled to the memory, the processor being configured to execute the control method of the drying apparatus according to any one of claims 15-28 based on instructions stored in the memory.

30. A control device for a drying equipment, comprising: A module for implementing the control method of the drying equipment according to any one of claims 15-28.

31. A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for the drying apparatus according to any one of claims 15-28.

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