Variable oil return system and air conditioning unit

Abstract

The utility model discloses a variable oil return system and air conditioning unit, including the main circulation system of containing compressor, set up the oil return unit of the discharge side of compressor, it is used for separating the mixed lubricating oil in refrigerant and flows back to compressor, set up the oil storage unit of the oil outlet side of oil return unit, it is used for storing the lubricating oil of oil return unit separation, to reduce the lubricating oil amount in main circulation system, set up the oil supplement unit between oil storage unit and compressor, it is used for the lubricating oil storage of oil storage unit exports to the compressor. Thus through the mutual coordination of oil return unit, oil storage unit and oil supplement unit, the lubricating oil amount in whole system is dynamically regulated, avoids the problem that lubricating oil is too much or too little, need not to increase or reduce lubricating oil to compressor additionally, thereby guarantees the normal operation of compressor, even guarantees the operation efficiency of whole system.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration technology, and in particular to a variable oil return system and an air conditioning unit. Background Technology

[0002] The amount of refrigerant oil required by a screw compressor varies depending on its operating conditions. For example, under high-pressure conditions, increased friction between the rotors necessitates more refrigerant oil for lubrication and cooling to prevent overheating and wear. Under low-pressure conditions, lower pressure and less friction result in a smaller amount of refrigerant oil required.

[0003] The amount of refrigerant oil in a conventional unit is determined during filling and cannot be adjusted according to actual conditions. Instead, it is necessary to add or remove refrigerant oil to the compressor based on different situations. If the refrigerant oil is too low, oil shortage problems are likely to occur, affecting the normal operation of the compressor; if the refrigerant oil is too high, it is likely to accumulate in the heat exchanger, affecting heat exchange efficiency and the overall control of the unit. Utility Model Content

[0004] This invention provides a variable oil return system and an air conditioning unit to solve the problem in the prior art that the refrigerant oil required by the compressor cannot be adjusted according to the actual situation, which affects the normal operation of the compressor.

[0005] The technical solution of this utility model is a variable oil return system, including a main circulation system containing a compressor; and further including:

[0006] The oil return unit installed on the discharge side of the compressor is used to separate the lubricating oil mixed in the refrigerant and return it to the compressor.

[0007] An oil storage unit is provided on the oil outlet side of the oil return unit to store the lubricating oil separated by the oil return unit, thereby reducing the amount of lubricating oil in the main circulation system.

[0008] An oil replenishment unit is installed between the oil storage unit and the compressor, which is used to output the lubricating oil stored in the oil storage unit to the compressor.

[0009] Furthermore, the oil storage unit includes a liquid storage tank, which is connected to the oil outlet side of the oil return unit via a first pipe, and a first solenoid valve is provided on the first pipe.

[0010] Furthermore, the compressor is provided with a first pressure detection device on the suction side. The first pressure detection device is used to detect the suction pressure of the compressor so as to determine whether the oil storage unit needs to be started based on the detected suction pressure.

[0011] Furthermore, the top of the liquid storage tank is connected to the suction side of the compressor via a second pipe, and a second solenoid valve is provided on the second pipe. The second solenoid valve is used to discharge the gas in the liquid storage tank.

[0012] Furthermore, the refueling unit includes:

[0013] A third pipe connects the liquid storage tank to the oil inlet side of the compressor, and a third solenoid valve is provided on the third pipe.

[0014] Furthermore, the top of the liquid storage tank is connected to the discharge side of the compressor via a fourth pipe, and a fourth solenoid valve is provided on the fourth pipe, which is used to allow gas to enter the liquid storage tank.

[0015] Furthermore, the vertical height of the oil outlet of the storage tank connected to the third pipeline is lower than the oil inlet of the storage tank connected to the first pipeline.

[0016] Furthermore, the compressor is provided with a second pressure detection device and a temperature detection device on the discharge side;

[0017] The second pressure detection device is used to detect the discharge pressure of the compressor, and the temperature detection device is used to detect the discharge temperature of the compressor, so as to determine whether the main circulation system needs to start the oil replenishment unit based on the detected discharge pressure and discharge temperature.

[0018] Furthermore, the oil return unit includes an oil separator;

[0019] The discharge side of the compressor is connected to the oil separator, and the oil outlet side of the oil separator is connected to the oil inlet side of the compressor through a fifth pipe, and a fifth solenoid valve is provided on the fifth pipe.

[0020] Furthermore, the oil separator is equipped with a liquid level detection device, which is used to detect the lubricating oil level in the oil separator.

[0021] This utility model also proposes an air conditioning unit, which includes the variable oil return system described above.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] This invention utilizes the coordinated operation of an oil return unit, an oil storage unit, and an oil replenishment unit. The oil storage unit stores the lubricating oil separated by the oil return unit, and the oil replenishment unit re-outputs the lubricating oil stored in the oil storage unit back into the system. This dynamically adjusts the amount of lubricating oil in the entire system, preventing problems of too much or too little lubricating oil. There is no need to add or reduce lubricating oil to the compressor, thus ensuring the normal operation of the compressor and even the operating efficiency of the entire system. Attached Figure Description

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this invention are used to distinguish different objects and not to describe a particular order.

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a block diagram of the variable oil return system proposed in this utility model;

[0027] Figure 2 This is a schematic diagram of the first variable oil return system proposed in this utility model;

[0028] Figure 3 This is a schematic diagram of the first fluid path of the first variable oil return system proposed in this utility model.

[0029] Figure 4 This is a schematic diagram of the second fluid path for the first variable oil return system proposed in this utility model.

[0030] Figure 5 This is a schematic diagram of the third fluid path for the first variable oil return system proposed in this utility model.

[0031] Figure 6 This is a schematic diagram of the second variable oil return system proposed in this utility model.

[0032] Figure label:

[0033] 10. Main circulation system;

[0034] 101. Compressor; 102. First pressure detection device; 103. Second pressure detection device; 104. Temperature detection device; 105. Condenser; 106. Expansion valve; 107. Shell and tube evaporator;

[0035] 20. Oil return unit;

[0036] 201. Oil separator; 202. Fifth pipeline; 203. Fifth solenoid valve; 204. Liquid level detection device;

[0037] 30. Oil storage unit;

[0038] 301. Storage tank; 302. First pipeline; 303. First solenoid valve; 304. Second pipeline; 305. Second solenoid valve; 306. First check valve;

[0039] 40. Fuel replenishment unit;

[0040] 401. Third pipeline; 402. Third solenoid valve; 403. Fourth pipeline; 404. Fourth solenoid valve; 405. Second check valve; 406. Oil pump. Detailed Implementation

[0041] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present utility model, and does not imply that every embodiment of the present utility model must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0042] The principle and structure of this utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0043] In existing technologies, the amount of refrigerant oil in the unit is determined during filling and cannot be adjusted according to actual conditions. Instead, it is necessary to add or remove refrigerant oil to the compressor based on different situations. If the refrigerant oil is too low, oil shortage problems are likely to occur, affecting the normal operation of the compressor; if the refrigerant oil is too high, it is likely to accumulate in the heat exchanger, affecting heat exchange efficiency and the overall control of the unit.

[0044] Therefore, in some embodiments, such as Figures 1-2 As shown, this utility model proposes a variable oil return system that can adjust the amount of refrigeration oil, including a main circulation system 10 containing a compressor 101; and further including:

[0045] The oil return unit 20, which is provided on the discharge side of the compressor 101, is used to separate the lubricating oil mixed in the refrigerant and return it to the compressor 101.

[0046] The oil storage unit 30, located on the oil outlet side of the oil return unit 20, is used to store the lubricating oil separated by the oil return unit 20, so as to reduce the amount of lubricating oil in the main circulation system 10.

[0047] An oil replenishment unit 40 is disposed between the oil storage unit 30 and the compressor 101, which is used to output the lubricating oil stored in the oil storage unit 30 to the compressor 101.

[0048] It should be noted that the lubricating oil proposed in this embodiment is preferably a refrigeration oil specifically adapted to the operating conditions of compressor 101, and the same applies throughout the text; and the compressor 101 proposed in this embodiment is preferably a screw compressor; the discharge side of compressor 101 proposed in this embodiment refers to the refrigerant outlet of compressor 101, and similarly, the suction side of compressor 101 refers to the refrigerant inlet of compressor 101. Furthermore, the variable oil return system proposed in this embodiment also includes a main control unit (not shown, the same applies throughout the text), which is electrically connected to the oil return unit 20, the oil storage unit 30, and the oil replenishment unit 40 respectively.

[0049] The main circulation system 10 also includes a condenser 105, an expansion valve 106, and a shell-and-tube evaporator 107. The discharge side of the compressor 101 is connected to the inlet side of the condenser 105. The discharge side of the condenser 105 is connected to the inlet side of the shell-and-tube evaporator 107 after passing through the expansion valve 106. The discharge side of the shell-and-tube evaporator 107 is connected to the suction side of the compressor 101, thereby forming the main circulation system 10 for flowing refrigerant.

[0050] Thus, the variable return oil system proposed in this embodiment has the following possible scenarios:

[0051] Firstly, such as Figure 3 As shown, during normal operation, the main control unit only activates the oil return unit 20 to separate the lubricating oil mixed in the refrigerant flowing out of the compressor 101 and return it to the compressor 101, thus preventing the lubricating oil from affecting the normal operation of the unit containing the compressor 101.

[0052] Secondly, such as Figure 4 As shown, in low-pressure operation (equivalent to excessive lubricating oil in the variable oil return system), the friction between the rotors of compressor 101 is small due to the low pressure, and less lubricating oil is required. Therefore, the main control unit simultaneously starts oil return unit 20 and oil storage unit 30 to divide the lubricating oil separated by oil return unit 20 into two parts. One part flows back to compressor 101, and the other part flows into oil storage unit 30 for storage, thereby reducing the amount of lubricating oil in the entire system and avoiding excessive lubricating oil in the system, which can easily accumulate on the shell and tube of shell and tube evaporator 107, affecting heat exchange efficiency and the overall operating efficiency of the system.

[0053] Thirdly, such as Figure 5 As shown, in high-pressure operation (equivalent to insufficient lubricating oil in the variable return oil system), the friction between the rotors of compressor 101 increases due to the higher pressure, requiring more lubricating oil for lubrication and cooling to prevent overheating and wear. Therefore, the main control unit simultaneously starts the return oil unit 20 and the replenishment oil unit 40, so that the return oil unit 20 still separates the lubricating oil and returns it all to compressor 101, while the replenishment oil unit 40 outputs the lubricating oil stored in the oil storage unit 30 to compressor 101 to increase the amount of lubricating oil in the entire system and avoid insufficient lubricating oil in the system, which can easily lead to oil shortage problems and affect the normal operation of compressor 101.

[0054] Therefore, this embodiment dynamically adjusts the amount of lubricating oil in the entire system through the coordinated operation of the oil return unit 20, the oil storage unit 30 and the oil replenishment unit 40, avoiding the problem of too much or too little lubricating oil. There is no need to add or reduce the lubricating oil to the compressor 101, thereby ensuring the normal operation of the compressor 101 and even ensuring the operating efficiency of the entire system.

[0055] In some embodiments, such as Figure 2 As shown, the oil return unit 20 includes an oil separator 201;

[0056] The discharge side of the compressor 101 is connected to the oil separator 201. The oil outlet side of the oil separator 201 is connected to the oil inlet side of the compressor 101 through the fifth pipe 202, and the fifth pipe 202 is equipped with a fifth solenoid valve 203.

[0057] In this way, when the system is running, the oil return unit 20 also operates. That is, the oil separator 201 separates the lubricating oil mixed with the refrigerant flowing out of the compressor 101. Then, the main control unit controls the fifth solenoid valve 203 to open, so that the lubricating oil in the oil separator 201 flows back to the compressor 101 through the fifth pipe 202, thus preventing the lubricating oil from affecting the normal operation of the unit containing the compressor 101.

[0058] In some embodiments, such as Figure 2 As shown, the oil storage unit 30 includes a liquid storage tank 301, which is connected to the oil outlet side of the oil return unit 20 through a first pipe 302. A first solenoid valve 303 is provided on the first pipe 302.

[0059] In this way, when there is too much lubricating oil in the system, the main control unit will open the first solenoid valve 303 and close the fifth solenoid valve 203, so that some of the lubricating oil in the oil separator 201 flows into the liquid storage tank 301 through the first pipe 302 for storage. The lubricating oil flowing into the liquid storage tank 301 does not participate in the refrigeration cycle and is stored for later use, so as to reduce the amount of lubricating oil in the system and avoid excessive lubricating oil in the system.

[0060] When the lubricating oil in the system changes from excessive to appropriate, that is, when there is no need to increase or decrease it, the main control unit closes the first solenoid valve 303 and opens the fifth solenoid valve 203 (that is, the valves in the system return to normal operation).

[0061] Furthermore, a first check valve 306 and a first solenoid valve 303 are sequentially provided along the lubricating oil flow path on the first pipe 302. The first check valve 306 is used to prevent the lubricating oil in the first pipe 302 from flowing back.

[0062] In a further embodiment, to ensure that the pressure inside the reservoir 301 remains balanced when storing lubricating oil, such as... Figure 2 As shown, the top of the liquid storage tank 301 is connected to the suction side of the compressor 101 through a second pipe 304. A second solenoid valve 305 is provided on the second pipe 304, which is used to discharge the gas in the liquid storage tank 301.

[0063] Thus, when there is too much lubricating oil in the system, the main control unit will open the first solenoid valve 303, close the fifth solenoid valve 203, and activate the second solenoid valve 305. This allows some of the lubricating oil in the oil separator 201 to flow into the storage tank 301 through the first pipe 302 for storage. The pressure difference on the suction side of the compressor 101 will then discharge the gas in the storage tank 301 through the second pipe 304, thus maintaining pressure balance in the storage tank 301. Of course, when the amount of lubricating oil in the system changes from too much to a suitable level, the main control unit will close the first solenoid valve 303, open the fifth solenoid valve 203, and close the second solenoid valve 305.

[0064] In a further embodiment, to ensure that the system can determine whether the lubricating oil in the oil separator 201 flows into the storage tank 301 for storage based on the suction pressure data of the compressor 101, such as... Figure 2 As shown, the compressor 101 is provided with a first pressure detection device 102 on the suction side. The first pressure detection device 102 is used to detect the suction pressure of the compressor 101 so as to determine whether the oil storage unit 30 needs to be started based on the detected suction pressure.

[0065] It should be noted that the first pressure detection device 102 proposed in this embodiment is preferably a pressure sensor.

[0066] In this way, the main control unit detects the suction pressure of the compressor 101 in real time through the first pressure detection device 102. When the suction pressure P1 is detected to be ≤300kPa and the load Q of the compressor 101 is ≤4×A0-100 (A0 is equivalent to the opening of the expansion valve 106, the same throughout the text), the main control unit determines that there is too much lubricating oil in the system. At this time, the main control unit will open the opening A1 of the first solenoid valve 303, close the opening A3 of the fifth solenoid valve 203, and start the second solenoid valve 305 so that part of the lubricating oil in the oil separator 201 flows into the liquid storage tank 301 through the first pipe 302 for storage. The lubricating oil flowing into the liquid storage tank 301 does not participate in the refrigeration cycle and is stored for later use, so as to reduce the amount of lubricating oil in the system and avoid excessive lubricating oil in the system.

[0067] When the suction pressure P1 is detected to be greater than 350 kPa and the load Q of compressor 101 is greater than 4 × A0 - 100, the main control unit determines that the amount of lubricating oil in the system is appropriate and there is no need to increase or decrease it. At this time, the main control unit closes the first solenoid valve 303, opens the fifth solenoid valve 203 to a greater degree A3, and closes the second solenoid valve 305 (that is, the valves in the system return to normal operation).

[0068] In some embodiments, such as Figure 2 As shown, the oil replenishment unit 40 includes:

[0069] A third pipe 401 connects the liquid storage tank 301 to the oil inlet side of the compressor 101, and a third solenoid valve 402 is provided on the third pipe 401.

[0070] Thus, when the lubricating oil level in the system is too low, the main control unit will increase the opening of the third solenoid valve 402 and the fifth solenoid valve 203, allowing the lubricating oil in the reservoir 301 to enter the compressor 101 through the third pipe 401 based on the pressure difference, thereby increasing the lubricating oil level in the system. When the lubricating oil level in the system returns to a suitable level, the main control unit will close the third solenoid valve 402 and decrease the opening of the fifth solenoid valve 203 (i.e., the valves in the system return to normal operating conditions).

[0071] Furthermore, a third solenoid valve 402 and a second check valve 405 are sequentially installed along the lubricating oil flow path on the third pipe 401. The second check valve 405 is used to prevent the lubricating oil in the third pipe 401 from flowing back.

[0072] In a further embodiment, to ensure that the pressure inside the reservoir 301 remains balanced when lubricating oil is output, such as... Figure 2As shown, the top of the liquid storage tank 301 is connected to the discharge side of the compressor 101 through a fourth pipe 403. A fourth solenoid valve 404 is provided on the fourth pipe 403, and the fourth solenoid valve 404 is used to allow gas to enter the liquid storage tank 301.

[0073] Thus, when the lubricating oil level in the system is too low, the main control unit will increase the opening of the third solenoid valve 402 and the fifth solenoid valve 203, and activate the fourth solenoid valve 404. This allows the lubricating oil in the reservoir 301 to enter the compressor 101 through the third pipe 401 based on the pressure difference, thereby increasing the lubricating oil level in the system. Meanwhile, the gas discharged from the compressor 101 will enter the reservoir 301 through the fourth pipe 403 to maintain pressure balance within the reservoir 301. Conversely, when the lubricating oil level in the system returns to a suitable level, the main control unit will close the third solenoid valve 402, decrease the opening of the fifth solenoid valve 203, and close the fourth solenoid valve 404.

[0074] Furthermore, in this embodiment, the oil storage unit 30 stores lubricating oil and the oil replenishment unit 40 replenishes lubricating oil through gravity and the pressure difference of the compressor 101, without the need for an additional pump structure, thus making the system's pipeline structure more streamlined and the cost lower.

[0075] Of course, in other embodiments, such as Figure 6 As shown, an oil pump 406 can also be installed on the third pipe 401 to draw the lubricating oil in the liquid storage tank 301 into the compressor 101 more quickly.

[0076] In some embodiments, the vertical height of the oil outlet of the storage tank 301 connected to the third pipe 401 is lower than the oil inlet of the storage tank 301 connected to the first pipe 302, so as to form a gravity flow path for the oil.

[0077] In this way, the lubricating oil can naturally sink from the high oil inlet to the low oil outlet by gravity, achieving oil gravity flow; it can also make the air bubbles carried in the oil float to the top of the liquid storage tank 301, preventing gas from entering the compressor 101 through the oil outlet, thus achieving gas-liquid separation.

[0078] In a further embodiment, to ensure that the system can determine whether the lubricating oil in the liquid receiver 301 is output to the compressor 101 based on the discharge pressure and discharge temperature data of the compressor 101, such as... Figure 2 As shown, the compressor 101 is provided with a second pressure detection device 103 and a temperature detection device 104 on the discharge side;

[0079] The second pressure detection device 103 is used to detect the discharge pressure of the compressor 101, and the temperature detection device 104 is used to detect the discharge temperature of the compressor 101, so as to determine whether the main circulation system 10 needs to start the oil replenishment unit 40 based on the detected discharge pressure and discharge temperature.

[0080] It should be noted that the second pressure detection device 103 proposed in this embodiment is preferably a pressure sensor, and the temperature detection device 104 is preferably a temperature sensor.

[0081] In this way, the main control unit detects the discharge pressure of the compressor 101 in real time through the second pressure detection device 103 and the discharge temperature of the compressor 101 in real time through the temperature detection device 104. When the discharge pressure P2 is detected to be ≥1200kPa and the discharge temperature T1 is detected to be ≥80℃, the main control unit determines that the system has entered a severe operating condition. The compressor 101 needs more lubricating oil for lubrication and cooling. At this time, the main control unit will open the opening degree A2 of the third solenoid valve 402, open the opening degree A3 of the fifth solenoid valve 203, and start the fourth solenoid valve 404 so that the lubricating oil in the liquid storage tank 301 enters the compressor 101 according to the pressure difference of the compressor 101, thereby increasing the amount of lubricating oil in the system. The gas discharged from the compressor 101 will enter the liquid storage tank 301 through the fourth pipe 403 to keep the pressure in the liquid storage tank 301 balanced.

[0082] If the main control unit detects that the exhaust pressure P2 < 1150 kPa and the exhaust temperature T1 < 80℃, it determines that the system has escaped the harsh working conditions, that is, the amount of lubricating oil in the system is appropriate and is in normal operation. At this time, the main control unit closes the third solenoid valve 402, opens the fifth solenoid valve 203 to a smaller degree A3, and closes the fourth solenoid valve 404.

[0083] In a further embodiment, to ensure that the system can determine whether the lubricating oil in the reservoir 301 is output to the compressor 101 based on the lubricating oil level data of the oil separator 201, such as... Figure 2 As shown, the oil separator 201 is equipped with a liquid level detection device 204, which is used to detect the lubricating oil level in the oil separator 201.

[0084] In this way, the main control unit monitors the lubricating oil level in the oil separator 201 in real time through the liquid level detection device 204. When the lubricating oil level is detected to be below the threshold, the main control unit will determine that there is too little lubricating oil in the system. At this time, the main control unit will open the third solenoid valve 402 to a larger degree A2, open the fifth solenoid valve 203 to a larger degree A3, and start the fourth solenoid valve 404 so that the lubricating oil in the storage tank 301 enters the compressor 101 according to the pressure difference of the compressor 101, thereby increasing the amount of lubricating oil in the system. The gas discharged from the compressor 101 will enter the storage tank 301 through the fourth pipe 403 to keep the pressure in the storage tank 301 balanced.

[0085] If the lubricating oil level reaches the threshold, the main control unit will determine that the amount of lubricating oil in the system is appropriate. At this time, the main control unit closes the third solenoid valve 402, opens the fifth solenoid valve 203 to a smaller degree A3, and closes the fourth solenoid valve 404.

[0086] In some embodiments, the present invention also provides an air conditioning unit, the air conditioning unit including the variable oil return system described above.

[0087] Therefore, this embodiment uses the coordinated operation of the oil return unit 20, the oil storage unit 30, and the oil replenishment unit 40 to dynamically adjust the amount of lubricating oil in the entire system by using data such as suction pressure, exhaust pressure, exhaust temperature, and lubricating oil level. This avoids problems of too much or too little lubricating oil and eliminates the need to add or reduce the amount of lubricating oil to the compressor 101, thereby ensuring the normal operation of the compressor 101 and the variable oil return system, and even ensuring the operating efficiency of the entire unit.

[0088] Specifically, in a properly commissioned refrigeration system, an air conditioning unit may experience one of the following four scenarios, and only one of these scenarios can occur at any given time:

[0089] Firstly, such as Figure 3 As shown, the air conditioning unit is operating normally. At this time, the main control unit only opens the fifth solenoid valve 203 so that the lubricating oil separated in the oil separator 201 flows back to the compressor 101 through the fifth pipe 202, so as to avoid the lubricating oil affecting the normal operation of the air conditioning unit.

[0090] Secondly, such as Figure 4As shown, there is too much lubricating oil in the air conditioning unit. That is, the main control unit detects that the suction pressure P1 ≤ 300 kPa and the load Q of the compressor 101 ≤ 4 × A0 - 100. At this time, the main control unit will open the opening A1 of the first solenoid valve 303, close the opening A3 of the fifth solenoid valve 203, and start the second solenoid valve 305 so that part of the lubricating oil in the oil separator 201 flows into the liquid storage tank 301 through the first pipe 302 for storage. The pressure difference on the suction side of the compressor 101 will discharge the gas in the liquid storage tank 301 through the second pipe 304 to keep the pressure in the liquid storage tank 301 balanced.

[0091] When the suction pressure P1 is detected to be greater than 350 kPa and the load Q of compressor 101 is greater than 4 × A0 - 100, the main control unit determines that the amount of lubricating oil in the air conditioning unit is appropriate. At this time, the main control unit closes the first solenoid valve 303, opens the fifth solenoid valve 203 to a greater degree A3, and closes the second solenoid valve 305, that is, the valves in the air conditioning unit return to normal operation.

[0092] Thirdly, such as Figure 5 As shown, the air conditioning unit has insufficient lubricating oil. Specifically, the main control unit detects that the exhaust pressure P2 ≥ 1200 kPa and the exhaust temperature T1 ≥ 80℃. The main control unit determines that the air conditioning unit has entered a severe operating condition, and the compressor 101 needs more lubricating oil for lubrication and cooling. At this time, the main control unit will open the third solenoid valve 402 to a greater extent A2, open the fifth solenoid valve 203 to a greater extent A3, and start the fourth solenoid valve 404. This allows the lubricating oil in the liquid receiver 301 to enter the compressor 101 according to the pressure difference of the compressor 101, thereby increasing the amount of lubricating oil in the air conditioning unit. Meanwhile, the gas discharged from the compressor 101 will enter the liquid receiver 301 through the fourth pipe 403 to keep the pressure in the liquid receiver 301 balanced.

[0093] When the exhaust pressure P2 < 1150 kPa and the exhaust temperature T1 < 80℃ are detected, it is determined that the system has left the harsh operating condition, that is, the amount of lubricating oil in the air conditioning unit is appropriate and is in normal operation. At this time, the main control unit closes the third solenoid valve 402, opens the fifth solenoid valve 203 to a smaller degree A3, and closes the fourth solenoid valve 404, that is, the valves in the air conditioning unit return to normal operation.

[0094] Fourth, such as Figure 5As shown, if the lubricating oil in the air conditioning unit is too low, that is, if the main control unit detects that the lubricating oil level has not reached the threshold, the main control unit will open the third solenoid valve 402 to a greater degree A2, open the fifth solenoid valve 203 to a greater degree A3, and start the fourth solenoid valve 404, so that the lubricating oil in the liquid storage tank 301 enters the compressor 101 according to the pressure difference of the compressor 101, thereby increasing the amount of lubricating oil in the air conditioning unit. Meanwhile, the gas discharged from the compressor 101 will enter the liquid storage tank 301 through the fourth pipe 403 to keep the pressure in the liquid storage tank 301 balanced.

[0095] When the lubricating oil level is detected to have reached the threshold, it is determined that the amount of lubricating oil in the air conditioning unit is appropriate. At this time, the main control unit closes the third solenoid valve 402, opens the fifth solenoid valve 203 to a smaller degree A3, and closes the fourth solenoid valve 404, that is, the valves in the air conditioning unit are restored to normal operation.

[0096] Obviously, the embodiments described above are only some embodiments of this utility model, not all embodiments. The accompanying drawings show preferred embodiments of this utility model, but do not limit the patent scope of this utility model. This utility model can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this utility model.

Claims

1. A variable oil return system, comprising a main circulation system (10) containing a compressor (101); characterized in that, Also includes: The oil return unit (20) provided on the discharge side of the compressor (101) is used to separate the lubricating oil mixed in the refrigerant and return it to the compressor (101); An oil storage unit (30) is provided on the oil outlet side of the oil return unit (20) to store the lubricating oil separated by the oil return unit (20) in order to reduce the amount of lubricating oil in the main circulation system (10). An oil replenishment unit (40) is provided between the oil storage unit (30) and the compressor (101) for outputting the lubricating oil stored in the oil storage unit (30) to the compressor (101).

2. The variable return oil system according to claim 1, characterized in that, The oil storage unit (30) includes a liquid storage tank (301), which is connected to the oil outlet side of the oil return unit (20) through a first pipe (302). A first solenoid valve (303) is provided on the first pipe (302).

3. The variable return oil system according to claim 1, characterized in that, The compressor (101) is provided with a first pressure detection device (102) on the suction side. The first pressure detection device (102) is used to detect the suction pressure of the compressor (101) so as to determine whether the oil storage unit (30) needs to be started based on the detected suction pressure.

4. The variable return oil system according to claim 2, characterized in that, The top of the liquid storage tank (301) is connected to the suction side of the compressor (101) through a second pipe (304). A second solenoid valve (305) is provided on the second pipe (304) and is used to discharge the gas in the liquid storage tank (301).

5. The variable return oil system according to claim 2, characterized in that, The refueling unit (40) includes: A third pipe (401) is provided on the oil inlet side of the liquid storage tank (301) and the compressor (101), and a third solenoid valve (402) is provided on the third pipe (401).

6. The variable return oil system according to claim 5, characterized in that, The top of the liquid storage tank (301) is connected to the discharge side of the compressor (101) through a fourth pipe (403). A fourth solenoid valve (404) is provided on the fourth pipe (403), which is used to allow gas to enter the liquid storage tank (301).

7. The variable return oil system according to claim 5, characterized in that, The vertical height of the oil outlet of the storage tank (301) connected to the third pipe (401) is lower than the oil inlet of the storage tank (301) connected to the first pipe (302).

8. The variable return oil system according to any one of claims 1 to 7, characterized in that, The compressor (101) is provided with a second pressure detection device (103) and a temperature detection device (104) on the discharge side; The second pressure detection device (103) is used to detect the discharge pressure of the compressor (101), and the temperature detection device (104) is used to detect the discharge temperature of the compressor (101), so as to determine whether the main circulation system (10) needs to start the oil replenishment unit (40) based on the detected discharge pressure and discharge temperature.

9. The variable return oil system according to any one of claims 1 to 7, characterized in that, The oil return unit (20) includes an oil separator (201); The discharge side of the compressor (101) is connected to the oil separator (201), and the oil outlet side of the oil separator (201) is connected to the oil inlet side of the compressor (101) through the fifth pipe (202), and the fifth pipe (202) is provided with a fifth solenoid valve (203).

10. The variable return oil system according to claim 9, characterized in that, The oil separator (201) is equipped with a liquid level detection device (204), which is used to detect the lubricating oil level in the oil separator (201).

11. An air conditioning unit, characterized in that, The air conditioning unit includes the variable oil return system as described in any one of claims 1 to 10.

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