Liquid taking structure, oil return system and air conditioning system

Abstract

The application discloses a kind of liquid taking structure, oil return system and air conditioning system, comprising: the shell of being formed liquid taking cavity by being arranged in the outside of evaporator, the float that is arranged in liquid taking cavity can follow liquid level rise and fall, one end pipe mouth is connected in the liquid taking pipe of float below liquid level, the outside of evaporator is sequentially provided with even gas hole and multiple liquid taking holes that communicate liquid taking cavity from top to bottom.The application forms liquid taking cavity between shell and evaporator by being arranged in the outside of evaporator, and even gas hole, high liquid taking hole, low liquid taking hole and even liquid hole of evaporator communicate the liquid taking cavity, to ensure that liquid level change in liquid taking cavity is consistent with evaporator, and float ball is arranged in liquid taking cavity, bottom end of float ball is always below liquid level, to ensure that float ball bottom end can take mixed liquid of rich oil layer in any working condition, any liquid level.Evaporator outside and shell between are provided with baffle and baffle, so that liquid level is kept stable, solve the problem of low lubricating oil content in liquid taking caused by liquid level fluctuation of evaporator when liquid taking.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a liquid extraction structure, an oil return system, and an air conditioning system. Background Technology

[0002] In refrigeration (heating) systems using oil bearings, lubricating oil frequently enters the refrigerant system through a seal, passes through the compressor discharge into the condenser, and then, along with the refrigerant, passes through a throttling device into the evaporator. The refrigerant evaporates in the evaporator and enters the compressor, while the lubricating oil accumulates above the liquid level in the evaporator. Gradually, the lubricating oil in the evaporator accumulates more and more, and the oil in the oil tank can no longer guarantee the lubrication and cooling of the unit's bearings, gears, etc. Insufficient oil can cause bearings and gears to seize, and structural damage. Therefore, the unit needs to be equipped with an oil return system to periodically return the lubricating oil from the rich oil layer above the liquid level in the evaporator to the oil tank to ensure adequate oil supply to the compressor.

[0003] Compared to general refrigeration, high-temperature heat pump units operate with larger temperature rises and higher pressure ratios, often requiring more compression stages. While general refrigeration systems use only single or two-stage compression, requiring only one compressor's bearings and gears for lubrication, high-temperature heat pumps with multi-stage compression cannot be adequately supplied with oil from a single compressor. This necessitates supplying oil to the bearings and gears of two or more compressors, making oil leakage particularly severe in high-temperature heat pump units and necessitating a stable and reliable oil return system.

[0004] Conventional ejector oil return, as shown in the attached document. Figure 1 The previous method of using two liquid sampling ports (one high and one low) in the evaporator to collect liquid only yielded an oil-rich mixture when the liquid level was near these ports. When the liquid level was far from the ports, it couldn't guarantee that the oil-rich mixture would be collected during oil return. Furthermore, due to unstable operating conditions, the liquid level in the evaporator fluctuated greatly, and high-speed gas was constantly generated. When the lubricating oil content in the evaporator was high, the gas mixed into the liquid, easily generating a large number of bubbles, resulting in a low lubricating oil content in the liquid collected by the ejector for oil return. This patent uses a liquid sampling chamber to create a more stable liquid level. A float ball is used to collect the liquid, ensuring that an oil-rich mixture can be collected under any operating condition. This guarantees stable oil return from the unit, increases the lubricating oil content in the collected liquid, and improves oil return efficiency. Summary of the Invention

[0005] In order to solve the technical problem of unstable lubricating oil extraction caused by evaporator liquid level fluctuations in the prior art, the present invention proposes a liquid extraction structure, an oil return system, and an air conditioning system.

[0006] The technical solution adopted in this invention is:

[0007] This invention proposes a liquid collection structure, comprising: a shell disposed on the outside of an evaporator to form a liquid collection chamber; a floating component disposed in the liquid collection chamber that can rise and fall with the liquid surface; a liquid collection pipe connected at one end to the floating component at a position below the liquid surface; and an equalization hole and a plurality of liquid holes connected to the liquid collection chamber are provided sequentially from top to bottom on the outside of the evaporator.

[0008] Specifically, the multiple liquid holes include: a high-level liquid sampling hole, a low-level liquid sampling hole, and a liquid equalization hole arranged sequentially.

[0009] Furthermore, the housing is also provided with a baffle that forms a gap with the outer shell of the evaporator. The baffle is provided with a plurality of air holes that are staggered with the air holes, and a through hole is provided staggered with each liquid hole.

[0010] Furthermore, the baffle plate is provided with a baffle plate to increase the flow path for each of the liquid holes.

[0011] Furthermore, the diameter of the through hole is two to three times the diameter of the corresponding liquid hole.

[0012] The present invention also proposes an oil return system, comprising: the above-described liquid extraction structure.

[0013] The oil return system specifically includes:

[0014] The first ejector pipe is connected to the bottom of the condenser at one end and to the air inlet of the compressor at the other end. The first ejector pipe is equipped with a first ejector device and a first solenoid valve. The other end of the liquid extraction pipe is connected to the first ejector device.

[0015] The second ejector pipe has one end connected to the bottom of the condenser or the first ejector pipe, and the other end connected to the bottom of the oil tank. The second ejector pipe is equipped with a second ejector device and a second solenoid valve.

[0016] The oil suction pipe is connected at one end to the compressor suction port and at the other end to the second ejector device.

[0017] Furthermore, at least one check valve is provided on the first ejector pipe, and a check valve is also provided on the oil suction pipe.

[0018] Furthermore, the top of the oil tank is provided with a balance pipe connected to the compressor's air intake, and the balance pipe is provided with a third solenoid valve with an adjustable opening.

[0019] Furthermore, the oil tank is equipped with a level sensor to detect the oil tank level. When the oil tank level is lower than the preset normal value, the first solenoid valve is opened. After a first preset time, the second solenoid valve is opened, and then the opening degree of the third solenoid valve is adjusted to the opening degree corresponding to the current working condition.

[0020] Furthermore, when the second solenoid valve has been open for a third preset time and the oil level in the tank is still lower than the preset normal value, the opening degree of the first solenoid valve, the second solenoid valve, and the third solenoid valve are increased.

[0021] The present invention also proposes an air conditioning system, including the aforementioned oil return system.

[0022] The air conditioning system specifically includes: a compressor, a condenser, a throttling device, and an evaporator that are circulated through pipes, and also includes an oil tank that is circulated through oil supply and return pipes to the compressor.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. A shell is installed on the outside of the evaporator, and a liquid collection chamber is formed between the shell and the evaporator. The gas equalization hole, high-level liquid collection hole, low-level liquid collection hole and liquid equalization hole of the evaporator are connected to the liquid collection chamber to ensure that the liquid level change in the liquid collection chamber is consistent with that of the evaporator.

[0025] 2. A float is installed in the liquid collection chamber, with the bottom of the float always 10-20mm below the liquid surface, to ensure that the bottom of the float can collect the oil-rich mixture under any working condition and at any liquid level.

[0026] 3. A baffle and a flow deflector are installed between the outer side of the evaporator and the shell. The diameter of the holes on the baffle for gas and liquid is 2 to 3 times that of the corresponding gas and liquid intake holes, so as to slow down the speed at which gas and liquid enter the liquid intake chamber and keep the liquid level in the liquid intake chamber relatively stable, thus solving the problem of low lubricating oil content in the liquid intake caused by the fluctuation of the liquid level in the evaporator during liquid intake.

[0027] 4. Use the high-pressure liquid from the condenser as the return oil driving force to return the mixture in the liquid intake chamber of the evaporator back to the oil tank through a secondary ejector.

[0028] 5. Connect a balance pipe to the top of the oil tank to the compressor suction end to maintain low pressure inside the oil tank and complete the oil return process. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the existing technology;

[0031] Figure 2 This is a schematic diagram of the structure in an embodiment of the present invention;

[0032] Figure 3 for Figure 2 A magnified view of a portion of the image;

[0033] Figure 4 This is a schematic diagram of the pipeline flow path in an embodiment of the present invention;

[0034] Figure 5 This is a flowchart from an embodiment of the present invention;

[0035] 1. Compressor; 2. Condenser; 3. Throttling device; 4. Evaporator; 5. First ejector device; 6. Second ejector device; 7. Third solenoid valve; 8. Oil cooler; 9. Oil filter; 10. Oil pump; 11. Oil tank; 12. Second solenoid valve; 13. First solenoid valve; 14. First check valve; 15. Second check valve; 16. Third check valve; 17. First ejector pipe; 18. Second ejector pipe; 19. Oil suction pipe; 41. Float; 42. Baffle; 43. Gas equalization port; 44. High-level liquid intake port; 45. Low-level liquid intake port; 46. Liquid equalization port; 47. Liquid intake pipe. Detailed Implementation

[0036] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention 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 invention and are not intended to limit the present invention.

[0037] The principles and structure of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0038] Conventional ejector oil return, such as Figure 1 The previous method of collecting liquid using two sampling ports (high and low) in the evaporator 4 only yielded a rich oil-bearing mixture when the liquid level was near these ports. When the liquid level was far from the ports, it couldn't guarantee that a rich oil-bearing mixture would be collected during oil return. Furthermore, due to unstable operating conditions, the liquid level in the evaporator fluctuated greatly, and high-speed gas was constantly generated. When the lubricating oil content in the evaporator was high, the gas mixed into the liquid, easily generating a large number of bubbles, resulting in a low lubricating oil content in the liquid collected by the ejector for oil return. This invention uses a liquid-collecting structure to create a more stable liquid level. By using a float to collect liquid, it ensures that a rich oil-bearing mixture can be collected under any operating condition, ensuring stable oil return from the unit, increasing the lubricating oil content in the collected liquid, and improving oil return efficiency.

[0039] like Figure 2 , 3As shown, this invention proposes a liquid collection structure, specifically including: a shell, a floating component, and a liquid collection pipe 47. The shell is fixed to the outside of the evaporator 4, and the area between the shell and the outside of the evaporator 4 forms a liquid collection chamber. From top to bottom, the outer side of the evaporator 4 covered by the shell is provided with a gas equalization hole 43 and multiple liquid holes, namely a high-level liquid collection hole 44, a low-level liquid collection hole 45, and a liquid equalization hole 46, ensuring that the liquid level in the liquid collection chamber is consistent with the liquid level in the evaporator 4. The floating component is placed inside the liquid collection chamber and can float according to the liquid level in the chamber. The liquid collection pipe 47 is a flexible tube, with one end fixed to the floating component and the pipe opening fixed to the bottom of the floating component. Due to gravity, the bottom of the floating component is always below the liquid level, so the pipe opening can always be below the liquid level. The specific distance from the liquid level can be changed by adjusting the volume or gravity of the floating component, ensuring that the bottom of the float 41 can collect the oil-rich mixture under any operating condition and at any liquid level, thereby improving the efficiency of oil return.

[0040] In a specific embodiment, the floating component can be a float 41, with the bottom of the float 41 always 10-20mm below the liquid surface, ensuring that the bottom of the float 41 can collect the oil-rich mixture under any working condition and at any liquid surface.

[0041] A liquid leveling hole 46 is also provided on the outer side of the evaporator 4 at a position lower than the low liquid intake hole 45 to ensure that the liquid level in the liquid intake chamber is consistent with the liquid level inside the evaporator 4.

[0042] like Figure 2 , 3 As shown, specifically, a baffle 42 is provided between the outer side of the evaporator 4 and the shell. A gap is formed between the baffle 43 and the outer side of the evaporator. The baffle 42 can be fixed inside the shell and spaced apart from the outer side of the evaporator 4. Because the outer side of the evaporator 4 is arc-shaped, the baffle 42 is also arc-shaped. The baffle 42 has multiple vent holes corresponding to the equalization holes 43, and the vent holes are staggered with the equalization holes 43. The diameter of the vent holes is two to three times that of the equalization holes 43 to prevent gas from directly and quickly entering the liquid collection chamber, affecting the stability of the liquid surface in the liquid collection chamber and preventing the generation of bubbles, thereby improving the purity of the oil-rich mixture in the liquid collection.

[0043] The air distribution hole 43 is suitable to be set 50-100mm above the liquid level under the design operating conditions of the unit. In this embodiment, it is set 100mm above the liquid level under the design operating conditions.

[0044] Each liquid outlet on the baffle 42 is equipped with a corresponding through-hole to stabilize the liquid surface. Specifically, the baffle 42 has a first through-hole offset from the high-level liquid outlet 44, a second through-hole offset from the low-level liquid outlet 45, and a third through-hole (or a gap can be left between it and the bottom surface of the shell) corresponding to the equalization hole 46. The diameter b of the first through-hole is two to three times the diameter a of the high-level liquid outlet 44, the diameter of the second through-hole is two to three times that of the low-level liquid outlet 45, and the diameter of the third through-hole is two to three times that of the equalization hole 46. Furthermore, a first baffle is provided between the first through-hole and the high-level liquid outlet 44, a second baffle is provided between the low-level liquid outlet 45 and the second through-hole, and a third baffle is provided between the third through-hole and the equalization hole 46 to slow down the liquid flow rate, ensuring a stable liquid surface in the liquid outlet chamber and preventing the generation of air bubbles.

[0045] like Figure 2 , 3 As shown, in addition to the high and low liquid sampling holes, other liquid sampling holes can be set between the high and low liquid sampling holes.

[0046] The baffle can be L-shaped or three plates connected vertically in sequence, with the length of the third plate being shorter than the length of the first plate for better baffle effect.

[0047] The liquid leveling hole 46 is appropriately set 50-100mm above the bottom tube sheet of the evaporator 4. In this example, the liquid leveling hole 46 is set 50mm above the bottom tube sheet of the evaporator 4. At the same time, a baffle plate and two through holes are set to ensure that the liquid level in the liquid taking chamber is stable and changes with the liquid level in the evaporator 4.

[0048] The oil-rich layer is generally within 10-20mm of the liquid surface, so the high-level liquid intake port 44 is set 10-20mm below the design operating liquid surface. The liquid surface of the extreme operating evaporator 4 is generally located 100-150mm below the design operating liquid surface, so the low-level liquid intake port 45 is set 100-150mm below the high-level liquid intake port 44. In this example, the high-level liquid intake port 44 is set 20mm below the design operating liquid surface, and the low-level liquid intake port 45 is set 150mm below the high-level liquid intake port 44. A float 41 is installed in the liquid intake chamber. According to the formula mg = ρgV, the weight and size of the float 41 are set so that the bottom of the float 41 is 20mm below the design operating liquid surface. The liquid intake pipe is connected to the bottom of the float 41 for liquid intake. The length of the liquid intake pipe must be greater than or equal to the internal height of the shell.

[0049] This invention also proposes an oil return system, including the aforementioned liquid extraction structure. Specifically, the oil return system proposed in this invention can be used in air conditioning systems with single-stage compressors or air conditioning systems with multi-stage compressors.

[0050] like Figure 4As shown, the oil return system specifically includes: a first ejector pipe 17, a second ejector pipe 18, and an oil suction pipe 19; one end of the first ejector pipe 17 is connected to the bottom of the condenser 2, and the other end is connected to the suction port of the compressor 1. The first ejector pipe 17 is equipped with a first ejector device 5 and a first solenoid valve 13. The first solenoid valve 13 is located in front of the first ejector device 5 (i.e., closer to the condenser 2). The liquid extraction pipe 47 is connected to the first ejector device 5. The first ejector pipe is equipped with multiple one-way valves; specifically, the first one-way valve 14 is located on the outlet side at the bottom of the condenser 2, and the second one-way valve 16 is located between the first ejector device 5 and the suction port of the compressor 1, ensuring that fluid does not return. The flow path is as follows: one end of the second ejector pipe 18 is connected to the bottom of the condenser 2 or to the first ejector pipe 17 (in the figure, it is directly connected to the first ejector pipe 17 to save pipework, and the connection point is located in front of the first solenoid valve 13), and the other end is connected to the bottom of the oil tank 11. The second ejector pipe is equipped with a second ejector device 6 and a second solenoid valve 12. The second solenoid valve 12 is also located in front of the second ejector device 6 (i.e., closer to the condenser 2). One end of the oil suction pipe is connected to the suction port of the compressor 1, and the other end is connected to the second ejector device 6. At the same time, the oil suction pipe is equipped with a third one-way valve 15, so that the fluid will only flow from the suction port of the compressor 1 towards the second ejector device 6.

[0051] During the specific oil return phase, the high-pressure liquid from the bottom of the condenser 2 passes quickly through the first ejector pipe and the first ejector device 5, causing a low pressure in the liquid collection pipe connected to the float 41 at the bottom of the first ejector device 5. The oil-rich mixture collected in the float 41 is sucked into the first ejector device 5 through the liquid collection pipe and carried to the suction end of the compressor 1 in the low-pressure stage. The suction end continues to suck in air to maintain a low pressure, and the refrigerant in the oil-rich mixture vaporizes and enters the compressor 1, completing the purification of the oil-rich mixture.

[0052] An oil suction pipe is connected to the second ejector device 6 at the suction end. High-pressure liquid from the bottom of the condenser 2 passes quickly through the second ejector device 6, causing a low pressure in the oil suction pipe at the bottom of the second ejector device 6 connected to the suction end of the compressor 1. The lubricating oil at the suction end of the compressor 1 is drawn into the second ejector device 6 and returns to the bottom of the oil tank 11. A balance pipe is installed at the top of the oil tank 11, connecting to the suction end of the compressor 1. A third solenoid valve 7 is installed on the balance pipe, and its opening degree can be adjusted. The remaining refrigerant in the lubricating oil evaporates into gas in the high-temperature oil tank 11 and returns to the suction end of the compressor through the balance pipe, reducing the oil tank pressure and making it easier for the lubricating oil to return to the oil tank.

[0053] The oil return system of the present invention also includes a controller (which can be the controller of the air conditioning system or a separate controller that communicates with the air conditioning system) and a level sensor installed at a preset normal liquid level in the oil tank 11, which can detect whether the liquid level in the oil tank 11 is lower than the preset normal value. The oil return can be initiated by detecting whether the unit is in the oil return phase, or the single oil return volume can be increased to accelerate the oil return speed.

[0054] like Figure 5 As shown, the specific control is as follows: real-time detection of the liquid level in the oil tank 11 to determine whether the liquid level in the oil tank 11 is lower than the preset normal value;

[0055] If so, check the opening and closing of the first solenoid valve 13 and the second solenoid valve 12. If they are both open and the opening time exceeds the third preset time, directly increase the opening degree of the first solenoid valve 13, the second solenoid valve 12, and the third solenoid valve 7. If they are not open, first open the first solenoid valve 13, wait for the first preset time, then open the second solenoid valve 12, and adjust the opening degree of the third solenoid valve 7 to the opening degree corresponding to the current working condition, and return to the step of checking the liquid level of the oil tank 11.

[0056] If not, check the opening and closing of the first solenoid valve 13 and the second solenoid valve 12. If both are open, close the first solenoid valve 13 first, wait for the first preset time, and then close the second solenoid valve 12, waiting for the next oil return phase. If neither is open, keep the first solenoid valve 13 and the second solenoid valve 12 closed, and wait for the next oil return phase.

[0057] The present invention also proposes an air conditioning system, including the aforementioned oil return system.

[0058] The air conditioning system can specifically be a high-temperature heat pump unit, including: a compressor 1, a condenser 2, a throttling device 3 and an evaporator 4 connected by a pipeline, and also including: an oil supply pipeline connecting the oil tank 11 and the compressor 1, an oil return pipeline connecting the compressor 1 and the oil tank 11, and an oil pump 10, an oil cooler 8 and an oil filter 9 installed on the oil supply pipeline.

[0059] Refrigeration (heating) cycle: Low-temperature, low-pressure liquid refrigerant exchanges heat with the outside in evaporator 4, evaporates and absorbs heat to become low-temperature, low-pressure refrigerant gas, enters compressor 1, is compressed by compressor 1 to become high-temperature, high-pressure gas, enters condenser 2, exchanges heat with the outside, condenses and releases heat to become high-temperature, high-pressure liquid, passes through throttling device 3 to become low-temperature, low-pressure liquid, enters evaporator 4, and completes the cycle.

[0060] Lubrication system: Lubricating oil enters oil pump 10 from oil tank 11, becomes high temperature and high pressure liquid, enters oil cooler 8 to be cooled into low temperature lubricating oil, enters oil filter 9 to filter impurities, enters compressor 1 through oil supply circuit to lubricate the bearings, gears, etc. of compressor 1, and then absorbs the heat of bearings, gears, etc., and returns to oil tank 11 through return oil pipeline to complete oil circuit circulation.

[0061] When the lubricating oil lubricates the bearings and other components of the compressor 1, a small amount of lubricating oil enters the refrigerant circulation loop through the oil seal, dissolves in the refrigerant, and enters the condenser 2 with the refrigerant. It then enters the evaporator 4 through the throttling device 3. The refrigerant absorbs heat and evaporates into gas, which enters the compressor 1 from above the evaporator 4 through the suction pipe. Meanwhile, the lubricating oil accumulates above the liquid surface in the evaporator 4. The aforementioned oil return system can extract the lubricating oil and send it back to the oil tank.

[0062] It should be noted that the terminology used above is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0063] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0064] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0065] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0066] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A liquid-collecting structure, characterized in that, include: A shell is set on the outside of the evaporator to form a liquid collection chamber. A floating component is set in the liquid collection chamber and can rise and fall with the liquid level. One end of the floating component is connected to a liquid collection pipe at a position below the liquid level. The outside of the evaporator is provided with a gas equalization hole and a plurality of liquid holes that communicate with the liquid collection chamber from top to bottom. The shell is also provided with a baffle that is spaced apart from the outer shell of the evaporator to form a gap. The baffle is provided with a plurality of gas holes that are staggered with the gas equalization hole, and a through hole is provided staggered with each of the liquid holes.

2. The liquid extraction structure as described in claim 1, characterized in that, The plurality of liquid holes include: a high-level liquid sampling hole, a low-level liquid sampling hole, and a liquid equalization hole arranged sequentially.

3. The liquid extraction structure as described in claim 1, characterized in that, The baffle plate is provided with a baffle plate to increase the flow path for each of the liquid holes.

4. The liquid extraction structure as described in claim 1, characterized in that, The diameter of the through hole is two to three times the diameter of the corresponding liquid hole, and the diameter of the air hole is also two to three times the diameter of the equalizing air hole.

5. An oil return system, characterized in that, include: The liquid extraction structure as described in any one of claims 1 to 4.

6. The oil return system as described in claim 5, characterized in that, include: The first ejector pipe is connected to the bottom of the condenser at one end and to the compressor suction port at the other end. The first ejector pipe is equipped with a first ejector device and a first solenoid valve. The other end of the liquid extraction pipe is connected to the first ejector device. The second ejector pipe has one end connected to the bottom of the condenser or the first ejector pipe, and the other end connected to the bottom of the oil tank. The second ejector pipe is equipped with a second ejector device and a second solenoid valve. The oil suction pipe is connected at one end to the compressor suction port and at the other end to the second ejector device.

7. The oil return system as described in claim 6, characterized in that, The first ejector pipe is equipped with at least one check valve, and the oil suction pipe is also equipped with a check valve.

8. The oil return system as described in claim 6, characterized in that, The top of the oil tank is equipped with a balance pipe that connects to the compressor's air intake, and the balance pipe is equipped with a third solenoid valve with an adjustable opening.

9. The oil return system as described in claim 6, characterized in that, The oil tank is equipped with a level sensor to detect the oil level. When the oil level is lower than the preset normal value, the first solenoid valve is opened. After a first preset time, the second solenoid valve is opened, and the opening of the third solenoid valve is adjusted to the opening corresponding to the current working condition.

10. The oil return system as described in claim 9, characterized in that, When the second solenoid valve has been open for a third preset time and the oil level in the tank is still lower than the preset normal value, the opening degree of the first solenoid valve, the second solenoid valve, and the third solenoid valve shall be increased.

11. An air conditioning system, characterized in that, Includes the oil return system as described in any one of claims 5 to 10.

12. The air conditioning system as described in claim 11, characterized in that, include: The compressor, condenser, throttling device, and evaporator are circulated and connected by pipelines, and the oil tank is also circulated and connected to the compressor via oil supply and return pipelines.

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