Refrigerant recovery device, refrigerant recovery system and control method thereof

Abstract

The present invention provides a refrigerant recovery device, a refrigerant recovery system and a control method thereof. The refrigerant recovery device includes a suction pipeline, an exhaust pipeline, an oil return pipeline and a compression pipeline. A first check valve is provided on the suction pipeline, and the first check valve conducts unidirectionally from the second interface of the suction pipeline towards the first interface; a first oil separator is provided on the oil return pipeline, the intake port of the first oil separator is connected to the pipeline between the first interface and the first check valve, the outlet port of the first oil separator is connected to the pipeline between the first check valve and the second interface through a second check valve, and the second check valve conducts unidirectionally from the outlet port of the first oil separator towards the second interface; the inlet end of the compression pipeline is connected to the pipeline between the outlet port of the first oil separator and the second check valve. This refrigerant recovery device can ensure that the oil separator can efficiently separate lubricating oil under both the operating conditions of the refrigeration equipment and the operating conditions of the recovery system.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigerant recovery, and specifically, to a refrigerant recovery device, a refrigerant recovery system and a control method thereof. Background Art

[0002] The emission of Freon gas will cause a series of environmental problems such as the destruction of the atmosphere, the greenhouse effect and the resulting global temperature rise. Refrigeration equipment using Freon refrigerant is applied in various industries, and there may be leaks of Freon refrigerant in all links from source production and detection to user use, after-sales maintenance and scrapping treatment, and there may even be phenomena such as unauthorized emissions by people. With the increasingly strict supervision of Freon refrigerant, it is necessary to strictly monitor, recycle and reuse the Freon refrigerant in the above-mentioned various process links. Especially during testing and maintenance, it is often necessary to transfer the refrigerant in the refrigeration equipment to ensure that the refrigerant does not leak into the atmospheric environment when the connecting pipe is disconnected.

[0003] After-sales maintenance is difficult to supervise, and it is even rarer to use refrigerant recovery equipment for after-sales maintenance. In particular, there are a large number of refrigerant leaks in the after-sales maintenance of household air conditioners. On the other hand, for some special air conditioners, especially the compressors of computer room air conditioners, are placed on the low-pressure indoor unit side. There are differences between the refrigerant for pressure holding and leak detection during production testing and the rated filling refrigerant of the unit. It is very difficult to accurately control the refrigerant filling amount in the unit at the time of leaving the factory during the frequent connection and testing process. Basically, it is only possible to evacuate and refill the refrigerant, which is very wasteful of refrigerant and results in high production costs; evacuating, pressure holding and refilling the refrigerant also wastes a lot of production time and results in low production efficiency.

[0004] It is necessary to develop a refrigerant recovery and adjustment device for accurately transferring the original refrigerant in the refrigeration equipment during production, detection and after-sales maintenance to ensure no waste and no leakage. There is an existing refrigerant recovery device that has been optimized and studied in this regard. However, when the recovery system involved in this patent operates, the refrigerant flow direction of the low-pressure refrigerant suction of the recovery compressor through the first oil separator is opposite to the conventional refrigerant flow direction of the oil separator, and it is impossible to achieve a high-efficiency oil separation effect. The lubricating oil remaining in the outdoor unit of the refrigeration equipment is more likely to enter the recovery compressor, resulting in lubricating oil mixing and affecting the lubricating oil amount of the recovery compressor. Summary of the Invention

[0005] The first object of the present invention is to provide a refrigerant recovery device that ensures the same refrigerant flow direction in the oil separator when the refrigeration equipment is operating and when the recovery system is operating, so that the oil separator can achieve efficient separation of lubricating oil in both cases.

[0006] The second object of the present invention is to provide a refrigerant recovery system having the above-mentioned refrigerant recovery device.

[0007] The third object of the present invention is to provide a control method for a refrigerant recovery system having the above-mentioned refrigerant recovery system.

[0008] To achieve the above first object, the present invention provides a refrigerant recovery device, including a suction pipeline, with a first interface and a second interface respectively arranged at both ends of the suction pipeline; an exhaust pipeline, with a third interface and a fourth interface respectively arranged at both ends of the exhaust pipeline; an oil return pipeline, the first end of the oil return pipeline is communicated with the suction pipeline, and the second end of the oil return pipeline is communicated with the exhaust pipeline; a compression pipeline, the outlet end of the compression pipeline is communicated with the exhaust pipeline; a first check valve is arranged on the suction pipeline, and the first check valve conducts unidirectionally from the second interface towards the first interface; a first oil separator is arranged on the oil return pipeline, the air inlet of the first oil separator is connected to the pipeline between the first interface and the first check valve, the air outlet of the first oil separator is connected to the pipeline between the first check valve and the second interface through a second check valve, the second check valve conducts unidirectionally from the air outlet of the first oil separator towards the second interface, and the oil outlet of the first oil separator is communicated with the exhaust pipeline; the inlet end of the compression pipeline is connected to the pipeline between the air outlet of the first oil separator and the second check valve.

[0009] As can be seen from the above solution, in the refrigeration equipment test step, the refrigerant enters the first oil separator through the first interface from the air outlet of the indoor unit, and then enters the indoor unit through the second check valve from the second interface; in the recovery step, the refrigerant in the outdoor unit comes out from the second interface, passes through the first check valve and the first oil separator and is then transported into the recovery compressor, and the refrigerant discharged from the recovery compressor is transported into the indoor unit after the lubricating oil separation operation of the second oil separator.

[0010] By setting the first check valve and the second check valve, it is ensured that the flow direction of the refrigerant in the oil separator is the same when the refrigeration equipment is operating and when the refrigerant recovery device is operating, so that the oil separator can achieve efficient separation of lubricating oil in both cases, avoiding the lubricating oil remaining in the outdoor unit of the refrigeration equipment from entering the recovery compressor, thus preventing lubricating oil mixing and affecting the lubricating oil amount of the recovery compressor, and solving the problem of low efficiency of the oil separator in the existing refrigerant recovery device during operation. In addition, by connecting an oil return pipeline at the inlet and outlet of the refrigerant recovery device, the refrigerating oil separated from the refrigeration equipment is recovered in advance, and the refrigerating oil recovery of the refrigerant recovery device itself is realized by connecting an oil return branch to the high and low pressure ports of the recovery compressor of the refrigerant recovery device.

[0011] Preferably, a third check valve is provided on the exhaust pipeline, and the third check valve conducts unidirectionally from the fourth interface towards the third interface; the second end of the oil return pipeline is provided with an oil return port, and the oil return port is connected to the pipeline between the third interface and the third check valve.

[0012] Furthermore, a first throttling component and a fourth check valve are also provided on the oil return pipeline. Both the first throttling component and the fourth check valve are located on the pipeline between the oil outlet of the first oil separator and the oil return port, and the fourth check valve conducts unidirectionally from the oil outlet of the first oil separator towards the oil return port.

[0013] Preferably, a solenoid valve, a recovery compressor, a second oil separator, a second throttling component, and a fifth check valve are provided on the compression pipeline; the inlet of the solenoid valve is connected to the pipeline between the gas outlet of the first oil separator and the second check valve, and the recovery compressor is arranged between the outlet of the solenoid valve and the inlet of the second oil separator; the gas outlet of the second oil separator is connected to the pipeline between the third interface and the third check valve through the fifth check valve, and the fifth check valve conducts unidirectionally from the gas outlet of the second oil separator towards the third interface; the oil outlet of the second oil separator is connected to the pipeline between the recovery compressor and the solenoid valve through the second throttling component.

[0014] Furthermore, the first throttling component and / or the second throttling component is a capillary tube.

[0015] To achieve the above second objective, the present invention provides a refrigerant recovery system, including an indoor unit, an outdoor unit, and the above refrigerant recovery device. The indoor unit is provided with an indoor compressor, and the indoor unit and the outdoor unit are connected and communicated through the refrigerant recovery device. The first interface is communicated with the gas outlet of the indoor unit, the third interface is communicated with the liquid inlet of the indoor unit, the second interface is communicated with the gas inlet of the outdoor unit, and the fourth interface is communicated with the liquid outlet of the outdoor unit.

[0016] Preferably, the first interface is connected to the gas outlet of the indoor unit through a first connecting pipe, the third interface is connected to the liquid inlet of the indoor unit through a second connecting pipe, the second interface is connected to the gas inlet of the outdoor unit, and the fourth interface is connected to the liquid outlet of the outdoor unit.

[0017] Furthermore, the indoor unit includes a liquid valve, an expansion valve, an evaporator, an indoor compressor, and a gas valve arranged in sequence along the refrigerant flow direction; the gas outlet of the indoor unit is located at the gas outlet end of the gas valve, and the liquid inlet of the indoor unit is located at the liquid inlet end of the liquid valve.

[0018] To achieve the above third objective, the present invention provides a control method for the above refrigerant recovery system. The control method includes: performing a vacuum pumping step; after detecting that the vacuum degree of the refrigerant recovery device is qualified, performing a refrigeration equipment test step; after detecting that the refrigeration equipment test is qualified, performing a conversion control step; the conversion control step includes: after the external fan stops running for a first preset time, stopping the operation of the indoor compressor and the internal fan, and starting the external fan; closing the gas valve, and after the pressures of the indoor unit and the outdoor unit are balanced, the conversion control step ends; after the conversion control step ends, performing a recovery step; the recovery step includes: opening the solenoid valve on the compression pipeline, and starting the recovery compressor, the internal fan, and the external fan.

[0019] As can be seen from the above solution, when the above refrigerant recovery system is connected to the refrigeration equipment, through different combinations of valve opening and closing and the operation control of the recovery compressor, problems such as refrigerant recovery after the online test and the mixing of the refrigeration oil between the refrigeration equipment and the refrigerant recovery device can be solved. There is no need for a special pressure vessel for storing refrigerant, ensuring the consistency of the refrigerant filling amount of the refrigeration equipment.

[0020] A preferred solution is that in the refrigeration equipment test step, the solenoid valve is closed. The refrigerant enters the first oil separator from the air outlet of the indoor unit through the first interface, and then enters the outdoor unit from the second interface through the second one-way valve. The lubricating oil separated by the first oil separator returns to the indoor unit from the third interface through the exhaust pipeline; in the recovery step, the refrigerant in the outdoor unit comes out from the second interface, is transported to the recovery compressor through the first one-way valve and the first oil separator, and after the refrigerant discharged from the recovery compressor undergoes the lubricating oil separation operation of the second oil separator, it is transported into the indoor unit. Description of the Drawings

[0021] Figure 1 is the system schematic diagram of an embodiment of the refrigerant recovery system of the present invention.

[0022] Figure 2 is the system schematic diagram of an embodiment of the refrigerant recovery device of the present invention.

[0023] The present invention will be further described below in conjunction with the drawings and embodiments. Detailed Embodiments

[0024] Refer to Figure 1 and Figure 2 , the refrigerant recovery system includes an indoor unit 1, an outdoor unit 2, and a refrigerant recovery device 3. The indoor unit 1 and the outdoor unit 2 are connected through the refrigerant recovery device 3.

[0025] The refrigerant recovery device 3 includes a suction pipeline 4, a discharge pipeline 5, an oil return pipeline 6, and a compression pipeline 7. The two ends of the suction pipeline 4 are respectively provided with a first interface 41 and a second interface 42. The two ends of the discharge pipeline 5 are respectively provided with a third interface 51 and a fourth interface 52. The first interface 41 and the air outlet 11 of the indoor unit 1 are connected by a gas fluorine pipe 8 serving as a first connecting pipe. The third interface 51 and the liquid inlet 12 of the indoor unit 1 are connected by a liquid fluorine pipe 9 serving as a second connecting pipe. The second interface 42 is connected to the air inlet of the outdoor unit 2, and the fourth interface 52 is connected to the liquid outlet of the outdoor unit 2. Moreover, the first interface 41 communicates with the air outlet 11 of the indoor unit 1, the third interface 51 communicates with the liquid inlet 12 of the indoor unit 1, the second interface 42 communicates with the air inlet of the outdoor unit 2, and the fourth interface 52 communicates with the liquid outlet of the outdoor unit 2.

[0026] The first end of the oil return pipeline 6 is communicated with the suction pipeline 4, and the second end of the oil return pipeline 6 is communicated with the discharge pipeline 5. A first one-way valve 43 is provided on the suction pipeline 4, and the first one-way valve 43 conducts unidirectionally from the second interface 42 towards the first interface 41. A first oil separator 61, a first throttling component 62, and a fourth one-way valve 63 are provided on the oil return pipeline 6. The air inlet 611 of the first oil separator 61 is connected to the pipeline between the first interface 41 and the first one-way valve 43. The air outlet 612 of the first oil separator 61 is connected to the pipeline between the first one-way valve 43 and the second interface 42 through a second one-way valve 64. The second one-way valve 64 conducts unidirectionally from the air outlet 612 of the first oil separator 61 towards the second interface 42. The oil outlet 613 of the first oil separator 61 is communicated with the discharge pipeline 5. A third one-way valve 53 is provided on the discharge pipeline 5, and the third one-way valve 53 conducts unidirectionally from the fourth interface 52 towards the third interface 51. The second end of the oil return pipeline 6 is provided with an oil return port 65, and the oil return port 65 is connected to the pipeline between the third interface 51 and the third one-way valve 53. Both the first throttling component 62 and the fourth one-way valve 63 are located on the pipeline between the oil outlet 613 of the first oil separator 61 and the oil return port 65. The fourth one-way valve 63 conducts unidirectionally from the oil outlet 613 of the first oil separator 61 towards the oil return port 65.

[0027] The inlet end of the compression pipeline 7 is connected to the pipeline between the air outlet 612 of the first oil separator 61 and the second one-way valve 64, and the outlet end of the compression pipeline 7 is communicated with the discharge pipeline 5.

[0028] The compression pipeline 7 is provided with a solenoid valve 71, a recovery compressor 72, a second oil separator 73, a second throttling component 74 and a fifth one-way valve 75. The inlet of the solenoid valve 71 is connected to the pipeline between the air outlet 612 of the first oil separator 61 and the second one-way valve 64, and the recovery compressor 72 is provided between the outlet of the solenoid valve 71 and the air inlet 731 of the second oil separator 73. In this embodiment, the gas outlet 732 of the second oil separator 73 is connected to the oil return port 65 through the fifth one-way valve 75. Optionally, the gas outlet 732 of the second oil separator 73 can also be connected to the exhaust pipeline 5 between the third interface 51 and the third one-way valve 53 through the fifth one-way valve 75, or the gas outlet 732 of the second oil separator 73 can also be connected to the oil return pipeline 6 between the fourth one-way valve 63 and the oil return port 65 through the fifth one-way valve 75. The fifth one-way valve 75 is unidirectionally conducted from the gas outlet 732 of the second oil separator 73 toward the third interface 51. The oil outlet 733 of the second oil separator 73 is connected to the pipeline between the recovery compressor 72 and the solenoid valve 71 through the second throttling component 74. Preferably, the first throttling component 62 and the second throttling component 74 are both capillaries.

[0029] The indoor unit 1 includes a liquid valve 13, an expansion valve 14, an evaporator 15, an indoor compressor 16 and a gas valve 17 which are arranged in sequence along the flow direction of the refrigerant. The gas outlet 11 of the indoor unit 1 is located at the gas outlet end of the gas valve 17, and the liquid inlet 12 of the indoor unit 1 is located at the liquid inlet end of the liquid valve 13. The indoor unit 1 also includes an indoor fan 18, and the outdoor unit 2 includes a condenser 21 and an outdoor fan 22. Fluorine injection nozzles are provided on both the gas valve 17 and the liquid valve 13, and the gas valve 17 and the liquid valve 13 can only be opened or closed manually. When the gas valve 17 and / or the liquid valve 13 are closed, the fluorine injection nozzle on the gas valve 17 or the liquid valve 13 can only be connected to the outdoor unit 2 and not connected to the indoor unit 1. Optionally, at this time, the fluorine injection nozzle on the gas valve 17 or the liquid valve 13 can also be connected only to the indoor unit 1 and not connected to the outdoor unit 2.

[0030] During the production test of the existing refrigeration equipment, the indoor unit 1 and the outdoor unit 2 are separated. At the same time, because the outdoor unit 2 is very simple, it is not equipped with a complex electronic control system, but the indoor unit 1 is complex and equipped with an electronic control system. Therefore, on the production line, the indoor unit 1 is mainly tested online and the refrigeration system leaks are detected. The usual practice is: a small amount of refrigerant is injected into the indoor unit 1 for leak detection, and the outdoor unit 2 is equipped with a sufficient amount of refrigerant using a test tool. After the indoor and outdoor units are connected, the test tool of the outdoor unit 2 is used to run with its own refrigerant. After the test is completed, the liquid valve 13 is closed and the refrigerant is fully pressed into the test tool of the outdoor unit 2 through the indoor compressor 16, including the small amount of refrigerant originally used for leak detection of the indoor unit 1. Since the same test fixture of the outdoor unit 2 is used, after testing multiple indoor units 1, the leak detection refrigerants of the numerous original indoor units 1 will be accumulated one by one in the test fixture of the outdoor unit 2, resulting in more and more refrigerant in the test fixture and more accumulation of refrigeration oil of the indoor compressor 16, which can only be discharged regularly or adjusted to other pressure vessels for storage, which affects the accuracy of the test and also causes waste of production costs, extension of production time, and reduction of production efficiency.

[0031] When the refrigerant recovery device 3 of the present invention is connected to the outdoor unit 2, the whole will be used as a test fixture for online testing on the production line. At this time, it is only necessary to connect the air outlet 11 of the indoor unit 1 with the first interface 41 through the gas fluorine tube 8, and connect the liquid inlet 12 of the indoor unit 1 with the third interface 51 through the liquid fluorine tube 9. At the same time, the rated filling amount of the unit in the indoor unit 1 is required to replace the original small amount of refrigerant for leak detection. When performing online testing, the valves on the first interface 41, the second interface 42, the third interface 51, the fourth interface 52, the air outlet 11 of the indoor unit 1 and the liquid inlet 12 of the indoor unit 1 are all opened. The above five valves can be manually controlled valves or automatically controlled valves. In addition, the five one-way valves can be automatically turned on or off according to the pressure difference at both ends.

[0032] The control method of the refrigerant recovery system comprises the following steps:

[0033] First, perform the vacuuming step. Connect the vacuum pump through the fluorine injection nozzle on the gas valve 17 and / or the liquid valve 13 to vacuum the refrigerant recovery device 3 and the outdoor unit 2. After the vacuuming is qualified, close the valve of the vacuum gauge, turn off the vacuum pump, and then open the gas valve 17 and the liquid valve 13, and then remove the vacuum gauge.

[0034] Next, perform the refrigeration equipment test step. In the refrigeration equipment test step, close the solenoid valve 71 and start the operation test of the refrigeration equipment. At this time, the refrigerant flow circulation route is as follows: After the refrigerant comes out of the indoor compressor 16, it first passes through the gas valve 17 and the air outlet 11 of the indoor unit 1, and then enters the first oil separator 61 through the first interface 41. The lubricating oil is separated through the first oil separator 61. The separated refrigerant enters the outdoor unit 2 through the second check valve 64 from the second interface 42. The lubricating oil separated by the first oil separator 61 enters the exhaust pipe 5 from the oil return port 65 after passing through the first throttling component 62 and the fourth check valve 63, and is mixed with the liquid refrigerant coming from the condenser 21 again and then returns to the indoor unit 1 from the third interface 51, so that the lubricating oil content in the outdoor unit 2 is greatly reduced, the mixing amount of the lubricating oil can be reduced in the recovery step, and the lubricating oil amount in the indoor unit 1 is basically balanced. The refrigerant entering the outdoor unit 2 comes out from the fourth interface 52 after passing through the condenser 21, and then successively passes through the third check valve 53, the third interface 51, the liquid inlet 12 of the indoor unit 1, the liquid valve 13, the expansion valve 14, and the evaporator 15 and then enters the indoor compressor 16.

[0035] Next, after detecting that the refrigeration equipment test is qualified, prepare to run the recovery step, and first perform the conversion control step before running the recovery step. The conversion control step includes: The first step, the external fan 22 stops running for the first preset time. The high-temperature and high-pressure refrigerant gas discharged from the indoor compressor 16 will wash the liquid refrigerant in the condenser 21 to make it return to the indoor unit 1 as soon as possible. Then, stop running the indoor compressor 16 and the internal fan 18, and start the external fan 22 to cool the residual refrigerant in the condenser 21. The second step, close the gas valve 17, and after waiting for the second preset time, when the indoor unit 1 and the outdoor unit 2 achieve pressure balance, the conversion control step ends.

[0036] Then, after the conversion control step is completed, the transition control between the refrigeration equipment test step and the recovery step is realized, and then the recovery step can be executed. The recovery step includes: opening the solenoid valve 71 on the compression pipeline 7, starting the recovery compressor 72, the indoor fan 18 and the outdoor fan 22. After starting the recovery compressor 72, the refrigerant remaining on the outdoor unit 2 is compressed back to the indoor unit 1 through the recovery compressor 72, and the speed of the indoor fan 18 is adjusted according to the pressure of the indoor unit 1, so that the high-temperature and high-pressure refrigerant gas discharged from the recovery compressor 72 into the evaporator 15 is condensed and liquefied as soon as possible. The high-speed operation of the outdoor fan 22 of the outdoor unit 2 makes the refrigerant liquid remaining in the condenser 21 gasify as soon as possible for the recovery compressor 72 to suck. The first oil separator 61 can separate and store the lubricating oil of the original refrigeration equipment and realize gas-liquid separation at the same time, so as to prevent the liquid refrigerant that has not been completely evaporated from directly returning to the recovery compressor 72; the second oil separator 73 can realize the separation of the refrigerant and lubricating oil at the outlet of the recovery compressor 72, so as to ensure the normal circulation of the lubricating oil of the recovery compressor 72 itself. The two oil separators can isolate the lubricating oil between the two compressors to the greatest extent, avoiding excessive mixing of the lubricating oil between the two, thereby ensuring that both compressors have sufficient lubricating oil.

[0037] In the recovery step, the refrigerant flow circulation route is: the refrigerant from the inlet end of the third one-way valve 53 first passes through the fourth interface 52 and the condenser 21, and after coming out from the second interface 42, it passes through the first one-way valve 43 and the first oil separator 61 and then is transported to the recovery compressor 72 through the solenoid valve 71. The refrigerant discharged from the recovery compressor 72 passes through the lubricating oil separation operation of the second oil separator 73, and then passes through the fifth one-way valve 75, the third interface 51, the liquid inlet 12 of the indoor unit 1, the liquid valve 13 and the expansion valve 14 in turn, and is finally recovered to the evaporator 15.

[0038] When it is detected that the suction pressure and temperature of the recovery compressor 72 are at the critical point Low, it indicates that the recovery of the refrigerant meets the requirements and the recovery mode can be stopped: after closing the liquid valve 13, the operation of the recovery compressor 72 and the external fan 22 is stopped, and after waiting for the third preset time, the operation of the internal fan 18 is stopped, and the solenoid valve 71 is closed.

[0039] After the recovery step is completed, most of the refrigerant in the refrigerant recovery device 3, the outdoor unit 2, the gas fluorine pipe 8 and the liquid fluorine pipe 9 has been recovered and returned to the indoor unit 1. Only a small amount of refrigerant gas remains in the pipeline between the liquid valve 13 and the outlets of the fourth check valve 63, the fifth check valve 75 and the third check valve 53, which is usually within the allowable error of the filling amount of the indoor unit 1.

[0040] In addition, an outlet valve is provided at the air outlet 11 of the indoor unit 1, and an inlet liquid valve is provided at the liquid inlet 12 of the indoor unit 1. After closing the outlet valve and the inlet liquid valve, and then disconnecting the air outlet 11 and the liquid inlet 12 of the indoor unit 1, the vacuum degree of the recovery system and the outdoor unit 2 can be maintained. After the next indoor unit 1 is connected, only the pipe section between the air outlet 11 of the indoor unit 1 and the air valve 17, and the pipe section between the liquid inlet 12 of the indoor unit 1 and the liquid valve 13 need to be evacuated, and the evacuation time required is greatly shortened. At the same time, it can also avoid the loss of lubricating oil caused by frequent evacuation of the refrigerant recovery device 3 and the outdoor unit 2.

[0041] As can be seen from the above solution, through the setting of the first one-way valve and the second one-way valve, it is ensured that the flow direction of the refrigerant in the oil separator is the same when the refrigeration equipment is operating and when the refrigerant recovery device is operating, so that the oil separator can achieve efficient separation of lubricating oil in both cases, avoiding the lubricating oil remaining in the outdoor unit of the refrigeration equipment from entering the recovery compressor, thereby causing lubricating oil mixing and affecting the lubricating oil volume of the recovery compressor, and solving the problem of low efficiency of the oil separator during the operation of the existing refrigerant recovery device. In addition, by connecting an oil return pipeline to the inlet and outlet of the refrigerant recovery device, the refrigerating oil separated from the refrigeration equipment is recovered in advance, and the refrigerating oil of the refrigerant recovery device itself is recovered through the connection of the high and low pressure ports of the recovery compressor of the refrigerant recovery device. When the above refrigerant recovery system is connected to the refrigeration equipment, through different combinations of valve opening and closing and the operation control of the recovery compressor, problems such as refrigerant recovery after the online test and mixing of the refrigerating oil between the refrigeration equipment and the refrigerant recovery device can be solved. There is no need for a special pressure vessel for storing refrigerant, ensuring the consistency of the refrigerant filling volume of the refrigeration equipment.

[0042] 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 modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Refrigerant recovery device, comprising: An intake pipe, with a first interface and a second interface respectively provided at both ends of the intake pipe; An exhaust pipe, with a third interface and a fourth interface respectively provided at both ends of the exhaust pipe; An oil return pipe, the first end of the oil return pipe is communicated with the intake pipe, and the second end of the oil return pipe is communicated with the exhaust pipe; A compression pipe, the outlet end of the compression pipe is communicated with the exhaust pipe; It is characterized in that: A first check valve is provided on the intake pipe, and the first check valve conducts unidirectionally from the second interface towards the first interface; A first oil separator is provided on the oil return pipe, the air inlet of the first oil separator is connected to the pipe between the first interface and the first check valve, the air outlet of the first oil separator is connected to the pipe between the first check valve and the second interface through a second check valve, the second check valve conducts unidirectionally from the air outlet of the first oil separator towards the second interface, and the oil outlet of the first oil separator is communicated with the exhaust pipe; The inlet end of the compression pipe is connected to the pipe between the air outlet of the first oil separator and the second check valve.

2. The refrigerant recovery device according to claim 1, characterized in that: A third check valve is provided on the exhaust pipe, and the third check valve conducts unidirectionally from the fourth interface towards the third interface; A second end of the oil return pipe is provided with an oil return port, and the oil return port is connected to the pipe between the third interface and the third check valve.

3. The refrigerant recovery device according to claim 2, characterized in that: A first throttling component and a fourth check valve are further provided on the oil return pipe, both the first throttling component and the fourth check valve are located on the pipe between the oil outlet of the first oil separator and the oil return port, and the fourth check valve conducts unidirectionally from the oil outlet of the first oil separator towards the oil return port.

4. The refrigerant recovery device according to claim 3, characterized in that: A solenoid valve, a recovery compressor, a second oil separator, a second throttling component and a fifth check valve are provided on the compression pipe; The inlet of the solenoid valve is connected to the pipe between the air outlet of the first oil separator and the second check valve, and the recovery compressor is arranged between the outlet of the solenoid valve and the air inlet of the second oil separator; The air outlet of the second oil separator is connected to the pipe between the third interface and the third check valve through the fifth check valve, and the fifth check valve conducts unidirectionally from the air outlet of the second oil separator towards the third interface; The oil outlet of the second oil separator is connected to the pipe between the recovery compressor and the solenoid valve through the second throttling component.

5. The refrigerant recovery device according to claim 4, characterized in that: The first throttling component and / or the second throttling component is a capillary tube.

6. A refrigerant recovery system, characterized in that, Comprising an indoor unit, an outdoor unit, and a refrigerant recovery device as described in any one of claims 1 to 5, wherein the indoor unit is provided with an indoor compressor, and the indoor unit and the outdoor unit are connected and communicated through the refrigerant recovery device; The first interface is communicated with the air outlet of the indoor unit, the third interface is communicated with the liquid inlet of the indoor unit, the second interface is communicated with the air inlet of the outdoor unit, and the fourth interface is communicated with the liquid outlet of the outdoor unit.

7. The refrigerant recovery system according to claim 6, characterized in that: The first interface is connected to the air outlet of the indoor unit through a first connecting pipe, the third interface is connected to the liquid inlet of the indoor unit through a second connecting pipe, the second interface is connected to the air inlet of the outdoor unit, and the fourth interface is connected to the liquid outlet of the outdoor unit.

8. The refrigerant recovery system according to claim 7, characterized in that: The indoor unit includes a liquid valve, an expansion valve, an evaporator, the indoor compressor, and a gas valve arranged in sequence along the refrigerant flow direction; The air outlet of the indoor unit is located at the air outlet end of the gas valve, and the liquid inlet of the indoor unit is located at the liquid inlet end of the liquid valve.

9. A control method for a refrigerant recovery system, characterized in that, The refrigerant recovery system adopts the refrigerant recovery system as described in any one of claims 6 to 8, and the control method includes: Performing a vacuum pumping step; After detecting that the vacuum degree of the refrigerant recovery device is qualified, performing a refrigeration equipment test step; After detecting that the refrigeration equipment test is qualified, performing a conversion control step; The conversion control step includes: After the external fan stops running for a first preset time, stopping the operation of the indoor compressor and the internal fan, and starting the external fan; Closing the gas valve, and after the pressure of the indoor unit and the outdoor unit is balanced, the conversion control step ends; After the conversion control step ends, performing a recovery step; The recovery step includes: opening the solenoid valve on the compression pipeline, and starting the recovery compressor, the internal fan, and the external fan.

10. The control method of the refrigerant recovery system according to claim 9, characterized in that: In the refrigeration equipment test step, closing the solenoid valve, the refrigerant enters the first oil separator from the air outlet of the indoor unit through the first interface, and then enters the outdoor unit from the second interface through the second one-way valve. The lubricating oil separated by the first oil separator passes through the exhaust pipeline and returns to the indoor unit from the third interface; In the recovery step, the refrigerant in the outdoor unit comes out from the second interface, passes through the first one-way valve and the first oil separator, and then is transported into the recovery compressor. The refrigerant discharged from the recovery compressor is transported into the indoor unit after the lubricating oil separation operation of the second oil separator.

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