Refrigerant recovery system and working method thereof

Abstract

The invention provides a refrigerant recovery system and a working method thereof, the refrigerant recovery system comprises a refrigerant system and a refrigeration cycle system, the refrigerant system comprises a dry filter, a first compressor, a first heat exchanger and a first liquid storage tank; the refrigeration cycle system comprises a second compressor, a second heat exchanger, a second liquid storage tank, a throttle valve and a third heat exchanger; the first end of the first pipeline is connected to the downstream side of the drying filter, the second end of the first pipeline is connected to the upstream side of the second compressor, the first valve is arranged on the first pipeline, the first end of the second pipeline is connected to the downstream side of the second compressor, and the second end of the second pipeline is connected to the downstream side of the first compressor. The second valve is arranged on the second pipeline; the third heat exchanger is arranged close to the first liquid storage tank or the first heat exchanger. The refrigerant system can improve the recovery speed and efficiency, and is simple in structure and low in cost.

Description

Technical Field

[0001] The present invention relates to the field of refrigerant recovery devices, and more specifically, to a refrigerant recovery system and its working method. Background Art

[0002] As Figure 1 shown, in a conventional refrigerant recovery system, gaseous refrigerant sequentially passes through a drying filter 101, a compressor 102, an oil separator 103, and a condenser 104, and enters a liquid storage tank 105. However, for a conventional refrigerant recovery system, when recovering refrigerant, since the liquid refrigerant in the system 100 to be recovered continuously vaporizes, its temperature continuously decreases (usually below 0 °C). The low-temperature gaseous refrigerant has a lower pressure and a smaller density, while the liquid refrigerant in the liquid storage tank 105 is high-pressure liquid refrigerant with a higher temperature (the temperature of the conventional system is higher than the ambient temperature). As a result, the high-low pressure ratio of the compressor 102 is large. A large high-low pressure ratio will reduce the compression efficiency of the compressor 102, and the low-density low-temperature gaseous refrigerant will reduce the recovery speed of the compressor 102 and the mass flow rate. Due to the large high-low pressure ratio, the refrigerant recovery speed is slow and the efficiency is low.

[0003] There is a conventional refrigerant recovery system that can effectively reduce the high-low pressure ratio of the compressor and thus improve the refrigerant recovery efficiency by increasing the temperature of the refrigerant in the air conditioner to be recovered and decreasing the temperature of the heat exchanger flowing to the liquid storage tank. However, this solution requires an additional coolant circulation system, increasing costs. At the same time, to decrease the temperature of the heat exchanger through a thermoelectric cooler, multiple heat exchangers and radiators are needed, resulting in a complex structure and high energy consumption. Summary of the Invention

[0004] The first object of the present invention is to provide a refrigerant recovery system that can improve the recovery speed and efficiency, has a simple structure, and low cost.

[0005] The second object of the present invention is to provide a working method for the above refrigerant recovery system.

[0006] To achieve the above-mentioned first purpose, the present invention provides a refrigerant recovery system, including a refrigerant system, the refrigerant system including a drying filter, a first compressor, a first heat exchanger and a first liquid storage tank connected in sequence through a refrigerant pipeline; the refrigerant recovery system also includes a refrigeration cycle system, the refrigeration cycle system including a second compressor, a second heat exchanger, a second liquid storage tank, a throttle valve and a third heat exchanger connected in sequence through a refrigerant circulation pipeline; the refrigerant recovery system also includes a first pipeline, a second pipeline, a first valve and a second valve; in the flow direction of the refrigerant, the first end of the first pipeline is connected to the downstream side of the drying filter, the second end of the first pipeline is connected to the upstream side of the second compressor, and the first valve is arranged on the first pipeline; in the flow direction of the refrigerant, the first end of the second pipeline is connected to the downstream side of the second compressor, the second end of the second pipeline is connected to the downstream side of the first compressor, and the second valve is arranged on the second pipeline; the third heat exchanger is arranged close to the first liquid storage tank and can perform heat exchange with the first liquid storage tank; or the third heat exchanger is arranged close to the first heat exchanger and can perform heat exchange with the first heat exchanger.

[0007] It can be seen from the above scheme that by setting up a refrigeration cycle system, the third heat exchanger in the refrigeration cycle system can exchange heat with the first liquid storage tank or the first heat exchanger, so as to quickly reduce the temperature of the recovered refrigerant, thereby reducing the pressure of the refrigerant entering the first liquid storage tank, and then reducing the high-low pressure ratio of the compressor inlet and exhaust ports when recovering the refrigerant, improving the refrigerant recovery efficiency, reducing the recovery time, and improving the energy recovery efficiency. At the same time, the refrigerant is transported to the refrigerant circulation pipeline through the first pipeline, and no additional refrigerant is added, thereby reducing costs. In addition, the first compressor and the second compressor are operated at the same time, and the refrigerant is transported to the first heat exchanger through the second pipeline, which can further greatly improve the recovery efficiency. At the same time, the above structure is simple, and the switching of steps can be achieved by controlling the opening and closing of each valve, which can greatly reduce costs.

[0008] A preferred solution is that the refrigerant recovery system also includes a third pipeline and a third valve; the first end of the third pipeline is connected to the pipeline between the drying filter and the first compressor, and the second end of the third pipeline is connected to the second liquid storage tank; the third valve is arranged on the third pipeline.

[0009] It can be seen that the setting of the third pipeline and the third valve can select whether to start the second compressor to drive the refrigerant into the second liquid storage tank according to the magnitude of the pressure difference within the system. For example, in the refrigerant charging step, first, open the third valve, and under the action of the pressure difference within the system, drive the refrigerant to flow into the second liquid storage tank. If the liquid level of the second liquid storage tank cannot reach the preset value within the preset time, then start the second compressor to make the liquid level of the second liquid storage tank reach an appropriate height, so as to achieve the energy-saving effect, and at the same time ensure that the liquid level in the second liquid storage tank reaches an appropriate value to ensure the normal operation of the third heat exchanger.

[0010] A further solution is that the refrigerant pipeline has a connection end for the air conditioner unit to be recycled, and a fourth valve is also provided on the refrigerant pipeline. The fourth valve is arranged between the connection end for the air conditioner unit to be recycled and the drying filter.

[0011] It can be seen that the fourth valve is used to open or close the connection end for the air conditioner unit to be recycled.

[0012] A further solution is that a liquid level sensor is arranged in the second liquid storage tank.

[0013] It can be seen that the liquid level sensor is used to detect the liquid level in the second liquid storage tank.

[0014] A further solution is that before recycling the refrigerant, the refrigerant recovery system first performs a vacuum pumping step. After the vacuum pumping is completed, it performs a step of charging the refrigerant into the refrigeration cycle system; the steps of refrigerant charging include: opening the third valve and the fourth valve, closing the remaining valves, and the refrigerant flows into the second liquid storage tank under the drive of the pressure difference; when the liquid level of the second liquid storage tank reaches the preset value within the preset time, close the third valve; when the liquid level of the second liquid storage tank cannot reach the preset value within the preset time, close the third valve, disconnect the third pipeline, and open the first valve to conduct the refrigerant circulation pipeline and operate the second compressor.

[0015] It can be seen that through the vacuum pumping operation, on the one hand, it can prevent air from existing in the system and polluting the recycled refrigerant, and on the other hand, it can also prevent other refrigerants inconsistent with the refrigerant to be recycled from existing in the system, thereby polluting the refrigerant to be recycled. In the refrigerant charging step, first, open the third valve and the fourth valve, and under the action of the pressure difference within the system, drive the refrigerant to flow into the second liquid storage tank. If the liquid level of the second liquid storage tank cannot reach the preset value within the preset time, then start the second compressor to make the liquid level of the second liquid storage tank reach an appropriate height, so as to achieve the energy-saving effect, and at the same time ensure that the liquid level in the second liquid storage tank reaches an appropriate value to ensure the normal operation of the third heat exchanger.

[0016] Preferably, a fifth valve and a first pressure sensor are further provided on the refrigerant pipeline; the fifth valve is located between the first connection position and the first compressor, and the first connection position is the position where the first pipeline is connected to the refrigerant pipeline; the first pressure sensor is located between the fifth valve and the first connection position.

[0017] It can be seen that the first pressure sensor is used to detect the pressure value at the intake port of the first compressor, and then reasonably control the opening and closing of each valve according to the pressure value.

[0018] Furthermore, a sixth valve and a second pressure sensor are further provided on the refrigerant pipeline; both the sixth valve and the second pressure sensor are located between the first heat exchanger and the first liquid storage tank, and the second pressure sensor is located between the sixth valve and the first liquid storage tank.

[0019] It can be seen that the second pressure sensor is used to detect the pressure value of the pipeline near the inlet of the first liquid storage tank, and then reasonably control the opening and closing of each valve according to the pressure value.

[0020] Furthermore, a seventh valve and an eighth valve are further provided on the refrigerant circulation pipeline; the seventh valve is located between the second connection position and the second heat exchanger, and the second connection position is the position where the second pipeline is connected to the refrigerant circulation pipeline; the eighth valve is located between the third heat exchanger and the third connection position, and the third connection position is the position where the first pipeline is connected to the refrigerant circulation pipeline.

[0021] Furthermore, a cold storage material is provided inside the third heat exchanger.

[0022] It can be seen that by setting the cold storage material, the third heat exchanger can have a stable temperature, so as to better cool the first heat exchanger or the first liquid storage tank.

[0023] Furthermore, after the refrigerant filling of the refrigeration cycle system is completed, the refrigerant recovery system performs the step of pre-cooling the cold storage material; the step of pre-cooling the cold storage material includes: opening the seventh valve and the eighth valve, running the second compressor, and when the temperature of the cold storage material drops to the preset temperature, first close the eighth valve, then close the seventh valve, and finally close the second compressor.

[0024] It can be seen that through the step of pre-cooling the cold storage material, the pre-cooling of the first liquid storage tank is realized, so as to ensure that at the initial state, the high and low pressure ratios at the inlet and outlet of the compressor during refrigerant recovery are relatively low, and the refrigerant recovery efficiency is improved.

[0025] A preferred solution is that the refrigerant recovery system can also perform the step of recovering refrigerant; the step of recovering refrigerant includes: opening the first valve, the second valve, the fourth valve, the fifth valve, and the sixth valve, closing the third valve, the seventh valve, and the eighth valve, and operating the first compressor and the second compressor.

[0026] Thus, by controlling each valve, it is ensured that the refrigerant can flow stably towards the first liquid storage tank.

[0027] A preferred solution is that during the refrigerant recovery process, when the detection value of the first pressure sensor is less than the first preset pressure value and greater than the second preset pressure value, or when the difference between the detection value of the second pressure sensor and the detection value of the first pressure sensor is greater than the preset pressure difference, close the first valve, the second valve, and the third valve, and open the fourth valve, the fifth valve, the sixth valve, the seventh valve, and the eighth valve; when the detection value of the first pressure sensor is less than the second preset pressure value, close the fourth valve and the seventh valve, open the remaining valves, and when the detection value of the first pressure sensor is less than the second preset pressure value again, close the sixth valve, the first compressor, and the second compressor.

[0028] Thus, when the detection value of the first pressure sensor is small, or when the detection value of the second pressure sensor is relatively large compared to the detection value of the first pressure sensor, the high-low pressure ratio of the compressor is large, which will reduce the compression efficiency of the compressor. At this time, by restarting the refrigerant circulation pipeline, the second compressor is used for cycle refrigeration, controlling the temperature of the third heat exchanger to further decrease, and then reducing the temperature of the refrigerant flowing towards the first liquid storage tank, thereby improving the recovery efficiency. If the detection value of the first pressure sensor is lower than the second preset pressure value, that is, lower than the pressure threshold, it indicates that the refrigerant recovery in the air conditioner unit to be recovered has been completed. At this time, the fourth valve can be closed. Then, the refrigerant inside the recovery system, when the detection value of the first pressure sensor is lower than the second preset pressure value again, it indicates that the refrigerant recovery inside the system has been completed, and the sixth valve and the two compressors can be closed.

[0029] To achieve the above second object, the present invention provides a working method of the above refrigerant recovery system. The working method includes: a vacuum pumping step of opening all valves and connecting a vacuum pump to the connection end of the air conditioner unit to be recovered in the refrigerant pipeline for vacuum pumping operation; a refrigerant filling step in which part of the refrigerant is driven to flow into the second liquid storage tank; a pre-cooling and temperature reduction step in which the refrigerant circulating in the refrigerant circulation pipeline absorbs heat by evaporation when passing through the third heat exchanger and exchanges heat with the first liquid storage tank / the first heat exchanger; a refrigerant recovery step of opening the valves on the refrigerant pipeline, conducting the refrigerant pipeline, and operating the first compressor and the second compressor. Description of the Drawings

[0030] Figure 1It is a schematic diagram of an existing refrigerant recovery system.

[0031] Figure 2 It is a schematic diagram of an embodiment of the refrigerant recovery system of the present invention.

[0032] Figure 3 It is the flow direction of the refrigerant in the first state during the refrigerant charging step of the embodiment of the refrigerant recovery system of the present invention.

[0033] Figure 4 It is the flow direction of the refrigerant in the second state during the refrigerant charging step of the embodiment of the refrigerant recovery system of the present invention.

[0034] Figure 5 It is the flow direction of the refrigerant during the precooling step of the embodiment of the refrigerant recovery system of the present invention.

[0035] Figure 6 It is the flow direction of the refrigerant during the refrigerant recovery step of the embodiment of the refrigerant recovery system of the present invention.

[0036] Figure 7 It is the flow direction of the refrigerant when the detection value of the first pressure sensor is greater than 0.1 Mpa and less than 0.2 Mpa during the refrigerant recovery step of the embodiment of the refrigerant recovery system of the present invention.

[0037] Figure 8 It is the flow direction of the refrigerant when the detection value of the first pressure sensor is less than 0.1 Mpa during the refrigerant recovery step of the embodiment of the refrigerant recovery system of the present invention.

[0038] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Specific Embodiments

[0039] Now, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and in no way limits the present invention and its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete and to fully convey the scope of the present invention to those skilled in the art. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, the compositions of materials, numerical expressions, and numerical values set forth in these embodiments should be construed as merely exemplary and not as limitations.

[0040] In the present invention, the terms "first", "second" and similar terms do not denote any order, quantity or importance, but are only used to distinguish different parts. Terms such as "comprising" or "including" mean that the elements before this term cover the elements listed after this term, and do not exclude the possibility of also covering other elements. Terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0041] In the present invention, when it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When it is described that a specific device is connected to other devices, the specific device may be directly connected to the other devices without an intermediate device, or may not be directly connected to the other devices and have an intermediate device.

[0042] All terms used in the present invention (including technical terms or scientific terms) have the same meaning as understood by those of ordinary skill in the art, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, for example, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such here.

[0043] Technologies, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods and devices should be regarded as part of the specification.

[0044] See Figure 2 , the refrigerant recovery system includes a refrigerant system 10 and a refrigeration cycle system 20. The refrigerant system 10 includes a dryer filter 11, a first compressor 12, a first heat exchanger 13 and a first liquid storage tank 14 connected in sequence through a refrigerant pipeline 15. The refrigeration cycle system 20 includes a second compressor 21, a second heat exchanger 22, a second liquid storage tank 23, a throttle valve 24 and a third heat exchanger 25 connected in sequence through a refrigerant circulation pipeline 26.

[0045] The refrigerant recovery system further includes a first pipeline 31, a second pipeline 32, a third pipeline 33, a first valve 41, a second valve 42 and a third valve 43. The first valve 41 is arranged on the first pipeline 31, the second valve 42 is arranged on the second pipeline 32, and the third valve 43 is arranged on the third pipeline 33.

[0046] In the refrigerant flow direction, the first end of the first pipeline 31 is connected to the downstream side of the dryer filter 11, and the second end of the first pipeline 31 is connected to the upstream side of the second compressor 21. In the refrigerant flow direction, the first end of the second pipeline 32 is connected to the downstream side of the second compressor 21, and the second end of the second pipeline 32 is connected to the downstream side of the first compressor 12. The first end of the third pipeline 33 is connected to the pipeline between the dryer filter 11 and the first compressor 12, and the second end of the third pipeline 33 communicates with the second liquid storage tank 23. The setting of the third pipeline 33 and the third valve 43 can select whether to start the second compressor 21 to drive the refrigerant into the second liquid storage tank 23 according to the magnitude of the pressure difference in the system.

[0047] The third heat exchanger 25 is disposed close to the first liquid storage tank 14 and can perform heat exchange with the first liquid storage tank 14. In other embodiments, the third heat exchanger 25 can also be disposed close to the first heat exchanger 13 and can perform heat exchange with the first heat exchanger 13. The third heat exchanger 25 is internally provided with a cold storage material. Optionally, the cold storage material is water.

[0048] A liquid level sensor (not shown) is disposed in the second liquid storage tank 23, and the liquid level sensor is used to detect the liquid level in the second liquid storage tank 23.

[0049] A fourth valve 44, a fifth valve 45, a sixth valve 46, a first pressure sensor 51, and a second pressure sensor 52 are further disposed on the refrigerant pipeline 15. The refrigerant pipeline 15 has a connection end 151 for the air conditioner unit to be recycled 6 to be connected. The fourth valve 44 is disposed between the connection end 151 for the air conditioner unit to be recycled and the dryer filter 11. The fifth valve 45 is located between the first connection position A1 and the first compressor 12. The first connection position A1 is the position where the first pipeline 31 is connected to the refrigerant pipeline 15. The first pressure sensor 51 is located between the fifth valve 45 and the first connection position A1. The first pressure sensor 51 is used to detect the pressure value at the air inlet of the first compressor 12. Both the sixth valve 46 and the second pressure sensor 52 are located between the first heat exchanger 13 and the first liquid storage tank 14. The second pressure sensor 52 is located between the sixth valve 46 and the first liquid storage tank 14. The second pressure sensor 52 is used to detect the pressure value of the pipeline near the inlet of the first liquid storage tank 14, and thus reasonably control the opening and closing of each valve according to the pressure value.

[0050] A seventh valve 47 and an eighth valve 48 are further disposed on the refrigerant circulation pipeline 26. The seventh valve 47 is located between the second connection position A2 and the second heat exchanger 22. The second connection position A2 is the position where the second pipeline 32 is connected to the refrigerant circulation pipeline 26. The eighth valve 48 is located between the third heat exchanger 25 and the third connection position A3. The third connection position A3 is the position where the first pipeline 31 is connected to the refrigerant circulation pipeline 26.

[0051] The working method of the refrigerant recovery system in this embodiment includes:

[0052] Vacuum pumping step: Open all valves, connect a vacuum pump to the connection end 151 of the air conditioner unit to be recovered on the refrigerant pipeline 15 for vacuum pumping operation. Stop vacuum pumping when the detected value of the second pressure sensor 52 is lower than 40 Pa, and close the fourth valve 44.

[0053] Refrigerant filling step: After vacuum pumping is completed, connect the connection end 151 of the air conditioner unit to be recovered to the air conditioner unit 6 to be recovered. Then, as Figure 3 shown, open the third valve 43 and the fourth valve 44, close the remaining valves. Under the action of the pressure difference inside the system, the refrigerant is driven to flow into the second liquid storage tank 23. When the liquid level of the second liquid storage tank 23 reaches the preset value within the preset time, close the third valve 43; when the liquid level of the second liquid storage tank 23 cannot reach the preset value within the preset time, as Figure 4 shown, close the third valve 43, disconnect the third pipeline 33, open the first valve 41 and the seventh valve 47, conduct the refrigerant circulation pipeline 26, and operate the second compressor 21 to make the liquid level of the second liquid storage tank 23 reach an appropriate height. After the liquid level of the second liquid storage tank 23 reaches the preset value, close the first valve 41 and the seventh valve 47. Optionally, the preset time is 20 s.

[0054] Precooling and temperature reduction step: After refrigerant filling is completed, as Figure 5 shown, open the seventh valve 47 and the eighth valve 48, operate the second compressor 21. The refrigerant circulating in the refrigerant circulation pipeline 26 enters the third heat exchanger 25 after passing through the throttle valve 24. When the refrigerant passes through the third heat exchanger 25, it evaporates and absorbs heat and can exchange heat with the first liquid storage tank 14. When the temperature of the cold storage material is reduced to the preset temperature, first close the eighth valve 48, then close the seventh valve 47, and finally close the second compressor 21. Optionally, the preset temperature is 0 °C.

[0055] Refrigerant recovery step: After precooling and temperature reduction of the cold storage material, as Figure 6 shown, open the valves on the refrigerant pipeline 15 to conduct the refrigerant pipeline 15, specifically open the first valve 41, the second valve 42, the fourth valve 44, the fifth valve 45, the sixth valve 46, close the third valve 43, the seventh valve 47 and the eighth valve 48, and operate the first compressor 12 and the second compressor 21.

[0056] During the refrigerant recovery process, when the detected value of the first pressure sensor 51 is less than the first preset pressure value and greater than the second preset pressure value, or when the difference between the detected value of the second pressure sensor 52 and the detected value of the first pressure sensor 51 is greater than the preset pressure difference, as Figure 7As shown, the first valve 41, the second valve 42 and the third valve 43 are closed, and the fourth valve 44, the fifth valve 45, the sixth valve 46, the seventh valve 47 and the eighth valve 48 are opened. Optionally, the first preset pressure value is 0.2Mpa, the second preset pressure value is 0.1Mpa, and the preset pressure difference is 10Mpa. In this step, the second compressor 21 is used for refrigeration cycle, so that the temperature of the third heat exchanger 25 is controlled at 3°C, which is used to reduce the refrigerant temperature in the first liquid storage tank 14, and the first compressor 12 continues to recover the refrigerant.

[0057] When the detection value of the first pressure sensor 51 is less than the second preset pressure value, Figure 8 As shown, the fourth valve 44 and the seventh valve 47 are closed, and the remaining valves are opened. When the detection value of the first pressure sensor 51 is less than the second preset pressure value again, the sixth valve 46, the first compressor 12 and the second compressor 21 are closed.

[0058] When the detection value of the first pressure sensor 51 is small, or the detection value of the second pressure sensor 52 is larger than the detection value of the first pressure sensor 51, the high and low pressures of the compressor are relatively large, which will reduce the compression efficiency of the compressor. At this time, by restarting the refrigerant circulation pipeline 26, the second compressor 21 is used for circulating refrigeration, and the temperature of the third heat exchanger 25 is controlled to be further reduced, thereby reducing the temperature of the refrigerant flowing to the first liquid storage tank 14, and improving the recovery efficiency. If the detection value of the first pressure sensor 51 is lower than the second preset pressure value, that is, lower than the pressure threshold, it means that the recovery of the refrigerant in the air-conditioning unit to be recovered has been completed. At this time, the fourth valve 44 can be closed, and then the refrigerant inside the system is recovered. When the detection value of the first pressure sensor 51 is lower than the second preset pressure value again, it means that the recovery of the refrigerant inside the system has been completed, and the sixth valve 46 and the two compressors can be closed.

[0059] As can be seen from the above, by setting up a refrigeration cycle system, the third heat exchanger in the refrigeration cycle system can exchange heat with the first liquid storage tank or the first heat exchanger, thereby quickly reducing the temperature of the recovered refrigerant, thereby reducing the pressure of the refrigerant entering the liquid storage tank, and then reducing the high-low pressure ratio of the compressor inlet and exhaust ports when recovering the refrigerant, improving the refrigerant recovery efficiency, reducing the recovery time, and improving the energy recovery efficiency. At the same time, the refrigerant is transported to the refrigerant circulation pipeline through the first pipeline, and no additional refrigerant is added, thereby reducing costs. In addition, the first compressor and the second compressor are operated at the same time, and the refrigerant is transported to the first heat exchanger through the second pipeline, which can further greatly improve the recovery efficiency. At the same time, the above structure is simple, and the switching of steps can be achieved by controlling the opening and closing of each valve, which can greatly reduce costs.

[0060] Finally, it should be emphasized that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A refrigerant recovery system, including a refrigerant system, the refrigerant system comprising a drying filter, a first compressor, a first heat exchanger, and a first liquid storage tank connected in sequence through a refrigerant pipeline; Characterized in that: The refrigerant recovery system further includes a refrigeration cycle system, the refrigeration cycle system comprising a second compressor, a second heat exchanger, a second liquid storage tank, a throttle valve, and a third heat exchanger connected in sequence through a refrigerant circulation pipeline; The refrigerant recovery system further includes a first pipeline, a second pipeline, a first valve, and a second valve; In the flowing direction of the refrigerant, the first end of the first pipeline is connected to the downstream side of the drying filter, the second end of the first pipeline is connected to the upstream side of the second compressor, and the first valve is provided on the first pipeline; In the flowing direction of the refrigerant, the first end of the second pipeline is connected to the downstream side of the second compressor, the second end of the second pipeline is connected to the downstream side of the first compressor, and the second valve is provided on the second pipeline; The third heat exchanger is disposed close to the first liquid storage tank and capable of performing heat exchange with the first liquid storage tank; or the third heat exchanger is disposed close to the first heat exchanger and capable of performing heat exchange with the first heat exchanger.

2. The refrigerant recovery system according to claim 1, characterized in that: The refrigerant recovery system further includes a third pipeline and a third valve; The first end of the third pipeline is connected to the pipeline between the drying filter and the first compressor, and the second end of the third pipeline communicates with the second liquid storage tank; The third valve is provided on the third pipeline.

3. The refrigerant recovery system according to claim 2, characterized in that: The refrigerant pipeline has a connection end for an air conditioner unit to be recovered, and a fourth valve is further provided on the refrigerant pipeline, and the fourth valve is provided between the connection end for the air conditioner unit to be recovered and the drying filter.

4. The refrigerant recovery system according to claim 3, characterized in that: A liquid level sensor is provided in the second liquid storage tank.

5. The refrigerant recovery system according to claim 4, characterized in that: Before recovering the refrigerant, the refrigerant recovery system first performs a vacuum pumping step, and after the vacuum pumping is completed, a refrigerant charging step for the refrigeration cycle system is performed; The refrigerant charging step includes: opening the third valve and the fourth valve, closing the remaining valves, and the refrigerant flows into the second liquid storage tank under the drive of the pressure difference; When the liquid level of the second liquid storage tank reaches a preset value within a preset time, the third valve is closed; When the liquid level of the second liquid storage tank cannot reach the preset value within a preset time, the third valve is closed, the third pipeline is disconnected, the first valve is opened, the refrigerant circulation pipeline is conducted, and the second compressor is operated.

6. The refrigerant recovery system according to any one of claims 3 to 5, characterized in that: A fifth valve and a first pressure sensor are further provided on the refrigerant pipeline; The fifth valve is located between the first connection position and the first compressor, and the first connection position is the position where the first pipeline is connected to the refrigerant pipeline; The first pressure sensor is located between the fifth valve and the first connection position.

7. The refrigerant recovery system according to claim 6, wherein: A sixth valve and a second pressure sensor are further provided on the refrigerant pipeline; Both the sixth valve and the second pressure sensor are located between the first heat exchanger and the first liquid storage tank, and the second pressure sensor is located between the sixth valve and the first liquid storage tank.

8. The refrigerant recovery system according to claim 7, wherein: A seventh valve and an eighth valve are further provided on the refrigerant circulation pipeline; The seventh valve is located between the second connection position and the second heat exchanger, and the second connection position is the position where the second pipeline is connected to the refrigerant circulation pipeline; The eighth valve is located between the third heat exchanger and the third connection position, and the third connection position is the position where the first pipeline is connected to the refrigerant circulation pipeline.

9. The refrigerant recovery system according to claim 8, wherein: The third heat exchanger is internally provided with a cold storage material.

10. The refrigerant recovery system according to claim 9, wherein: After the refrigerant charging of the refrigeration cycle system is completed, the refrigerant recovery system performs the step of pre-cooling the cold storage material; The step of pre-cooling the cold storage material includes: opening the seventh valve and the eighth valve, operating the second compressor, and when the temperature of the cold storage material drops to a preset temperature, first closing the eighth valve, then closing the seventh valve, and finally closing the second compressor.

11. The refrigerant recovery system according to claim 8, wherein: The refrigerant recovery system can also perform the step of recovering refrigerant; The step of recovering refrigerant includes: opening the first valve, the second valve, the fourth valve, the fifth valve, and the sixth valve, closing the third valve, the seventh valve, and the eighth valve, and operating the first compressor and the second compressor.

12. The refrigerant recovery system according to claim 8, wherein: During the refrigerant recovery process, when the detected value of the first pressure sensor is less than the first preset pressure value and greater than the second preset pressure value, or the difference between the detected value of the second pressure sensor and the detected value of the first pressure sensor is greater than the preset pressure difference, close the first valve, the second valve, and the third valve, and open the fourth valve, the fifth valve, the sixth valve, the seventh valve, and the eighth valve; When the detected value of the first pressure sensor is less than the second preset pressure value, close the fourth valve and the seventh valve, open the remaining valves, and when the detected value of the first pressure sensor is less than the second preset pressure value again, close the sixth valve, the first compressor, and the second compressor.

13. A working method of a refrigerant recovery system, characterized in that Applied to the refrigerant recovery system according to any one of claims 1 to 12, the working method includes: Vacuum pumping step: Open all valves, and connect a vacuum pump to the connection end of the air conditioner unit to be recovered in the refrigerant pipeline for vacuum pumping operation; Refrigerant charging step: Part of the refrigerant is driven to flow into the second liquid storage tank; Precooling and temperature reduction step: When the refrigerant circulating in the refrigerant circulation pipeline passes through the third heat exchanger, it evaporates and absorbs heat and exchanges heat with the first liquid storage tank / the first heat exchanger; Refrigerant recovery step: Open the valves on the refrigerant pipeline, conduct the refrigerant pipeline, and operate the first compressor and the second compressor.

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