Refrigerating system capable of automatically returning liquid

Abstract

The invention provides an automatic liquid return refrigerating system which comprises an evaporator, a gas-liquid separator and an oil separator, and the interior of the gas-liquid separator communicates with the interior of the evaporator through a liquid return pipe so that liquid in the evaporator can be guided into the gas-liquid separator; the gas-liquid separator further comprises a gas return pipe, one end of the gas return pipe is communicated with the interior of the gas-liquid separator, and the other end of the gas return pipe is communicated with the interior of the oil separator, so that gas separated from the interior of the gas-liquid separator can be guided into the oil separator through the gas return pipe. And liquid at the bottom in the oil separator can also flow back to the gas-liquid separator through the gas return pipe. According to the invention, the problems that the quantity of refrigerants participating in circulation in the system is too small and the heat exchange performance of the evaporator is influenced due to liquid gathering at the middle lower part of the evaporator and / or at the middle lower part of the gas collecting main pipe of the evaporator can be solved, and the problem of liquid seal caused by liquid entering the condenser is also solved.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration, and in particular to an automatic liquid return refrigeration system. Background Art

[0002] With the extensive application of 4G and the gradual popularization of 5G, the heat generated by various data processing equipment is getting higher and higher, and data centers have higher and higher requirements for the cooling capacity and energy saving of air-conditioning equipment.

[0003] Using outdoor natural cold sources in transitional seasons and cold winters to cool the data center can significantly reduce the operating costs of air-conditioning equipment. A common method is to use fluorine pump air conditioners. In winter, the fluorine pump mode is enabled, the compressor is stopped, and the fluorine pump is used to drive the refrigerant to achieve heat pipe cooling operation, which greatly reduces the operating costs of the equipment.

[0004] The fluorine pump compression refrigeration system is a composite system. The fluorine pump heat pipe system and the compression refrigeration system share the evaporator and condenser, as well as some common refrigerant pipelines, system components, etc.

[0005] In the fluorine pump refrigeration mode of the above-mentioned composite system, the refrigerant gas at the outlet of the evaporator may carry a large amount of refrigerant liquid that has not been completely evaporated. These refrigerant liquids are prone to accumulation on the gas pipeline before entering the condenser, resulting in liquid blockage, thereby blocking the flow of refrigerant gas in certain channels, thus affecting the gas distribution uniformity and heat exchange efficiency of the condenser; liquid blockage will also affect the flow resistance of the fluorine pump heat pipe cycle, and easily destroy the stable operation of the fluorine pump. Therefore, it is necessary to intercept the refrigerant liquid at the outlet of the evaporator and prevent it from returning to the condenser. The more refrigerant liquid is intercepted, the less refrigerant liquid remains in the liquid storage tank, posing a threat to the operational reliability of the fluorine pump, so the intercepted refrigerant liquid must be returned to the liquid storage tank as soon as possible.

[0006] In order to prevent the liquid refrigerant in the evaporator from entering the compressor or condenser in the compression refrigeration mode, the return gas main is usually connected to the highest possible liquid level in the gas collecting main of the evaporator. However, this can easily cause liquid refrigerant and lubricating oil to remain at the bottom of the gas collecting main, because the refrigerant flow rate of the bottom branch is small and the flow rate is low, and it cannot carry enough liquid refrigerant and / or lubricating oil to flow upward. After running for too long, liquid refrigerant and some lubricating oil are likely to accumulate at the bottom of the gas collecting main. When the height of these liquids gradually rises, the bottom branch is likely to form a liquid seal, and the refrigerant flow that can pass through is less, resulting in the formation of "liquid storage" at the bottom of the evaporator. Obviously, these liquid refrigerants will also contain more lubricating oil, which is likely to cause insufficient refrigerant circulation and insufficient oil return in the refrigeration system; in the fluorine pump refrigeration mode, the more liquid refrigerant accumulates at the bottom of the evaporator, the less refrigerant liquid flows in the liquid storage tank, and the corresponding liquid level height in the liquid storage tank is low, which is likely to cause fluorine pump cavitation.

[0007] Therefore, it is necessary to solve the problem of liquid accumulation in the middle and lower part of the evaporator and / or the middle and lower part of the gas collecting main pipe of the evaporator to avoid too little refrigerant circulating in the system and affect the heat exchange performance of the evaporator.

[0008] Since the fluorine pump refrigeration system in the prior art has liquid accumulated in the middle and lower part of the evaporator and / or the middle and lower part of the gas collecting main pipe of the evaporator, resulting in too little refrigerant circulating in the system and affecting the heat exchange performance of the evaporator, the present invention studies and designs a refrigeration system with automatic liquid return. Summary of the invention

[0009] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the fluorine pump compression refrigeration system in the prior art that liquid accumulates in the middle and lower part of the evaporator and / or the middle and lower part of the gas collecting main pipe of the evaporator, resulting in too little refrigerant circulating in the system and affecting the heat exchange performance of the evaporator, thereby providing a refrigeration system with automatic liquid return.

[0010] In order to solve the above problems, the present invention provides a refrigeration system with automatic liquid return, which comprises:

[0011] An evaporator, a gas-liquid separator and an oil separator, wherein the interior of the gas-liquid separator is connected to the interior of the evaporator through a liquid return pipe so that the liquid inside the evaporator can be led out to the gas-liquid separator;

[0012] It also includes a return air pipe, one end of which is connected to the interior of the gas-liquid separator, and the other end of which is connected to the interior of the oil separator, so that the gas separated inside the gas-liquid separator can be introduced into the oil separator through the return air pipe, and the liquid at the bottom of the oil separator can be refluxed back into the gas-liquid separator through the return air pipe.

[0013] In some embodiments,

[0014] A one-way valve B is provided on the return air pipe, and the one-way valve B is configured to allow air flow only from the interior of the gas-liquid separator to flow into the oil separator, while allowing liquid inside the oil separator to flow back into the gas-liquid separator; the height of the bottom of the oil separator is higher than the height of the top of the gas-liquid separator, so that the liquid at the bottom of the oil separator can automatically return to the gas-liquid separator through the return air pipe by gravity.

[0015] In some embodiments,

[0016] The oil separator has oil at a first preset height inside, the return air pipe is inserted into the oil separator from the bottom of the oil separator, and the height of the return air pipe inserted into the oil separator does not exceed the height of the oil in the oil separator.

[0017] In some embodiments,

[0018] It also includes a blocking structure and a floating plug,

[0019] The blocking structure is arranged in the gas-liquid separator, and the blocking structure divides the internal cavity of the gas-liquid separator into an upper cavity and a lower cavity, the upper cavity forms a separation chamber, and the lower cavity forms a liquid storage chamber, a communication hole is arranged through the blocking structure from top to bottom and / or a communication hole is formed between the blocking structure and the inner wall of the gas-liquid separator, and the communication hole connects the separation chamber and the liquid storage chamber;

[0020] A liquid outlet is also provided at the bottom of the gas-liquid separator, and the float is provided at the liquid outlet. At least part of the structure of the float is located in the liquid storage chamber, and at least part of the structure is located in the liquid outlet. The float can rise with the increase of the liquid level in the liquid storage chamber. When the liquid level in the liquid storage chamber is greater than or equal to a second preset height, the float is floated by the liquid and opens the liquid outlet. When the liquid level in the liquid storage chamber is less than the second preset height, the float falls due to its gravity and closes the liquid outlet.

[0021] In some embodiments,

[0022] The blocking structure is a windshield structure, which can block at least part of the airflow in the separation chamber from entering the liquid storage chamber. The gas-liquid separator is a cylindrical structure with a central axis. The connecting hole is arranged at a position closer to the inner wall of the gas-liquid separator than the central axis. There are multiple connecting holes, and the multiple connecting holes are arranged at intervals in the circumferential direction of the windshield.

[0023] In some embodiments,

[0024] It also includes an air inlet pipe, and the evaporator also includes an air collecting pipe, which is located at the outlet end of the evaporator. One end of the air inlet pipe is connected to the separation chamber, and the other end is connected to the air collecting pipe, so that the gas generated by the evaporator can be introduced into the separation chamber. One end of the liquid return pipe is connected to the liquid storage chamber, and the other end is connected to the bottom of the air collecting pipe. One end of the return pipe is connected to the separation chamber.

[0025] In some embodiments,

[0026] It also includes a compressor and an air outlet pipe, one end of the air outlet pipe is connected to the separation chamber of the gas-liquid separator, and the other end can be connected to the air intake port of the compressor, so that the gas separated inside the gas-liquid separator can be introduced into the compressor through the air outlet pipe.

[0027] In some embodiments,

[0028] It also includes a condenser, a first pipeline, a second pipeline and a third pipeline, one end of the first pipeline is connected to the air outlet of the compressor, and the other end is connected to the inner top of the oil separator, one end of the second pipeline is connected to the inner top of the oil separator, and the other end is connected to one end of the condenser, one end of the third pipeline is connected to the air outlet pipe, and the other end is connected to the return pipe, and a throttling device is provided on the third pipeline.

[0029] In some embodiments,

[0030] An air inlet, an air return port and an air outlet are provided on the top plate of the gas-liquid separator; one end of the air inlet pipe is inserted into the separation chamber of the gas-liquid separator through the air inlet, and the other end is connected to the interior of the air collecting pipe; the air return pipe is inserted into the separation chamber of the gas-liquid separator through the air return port, and the air outlet pipe is inserted into the separation chamber of the gas-liquid separator through the air outlet.

[0031] In some embodiments,

[0032] The air outlet pipe is a U-shaped tube structure, one end of the U-shaped tube is located in the separation chamber so as to be able to suck fluid from the separation chamber, and the other end of the U-shaped tube passes through the top of the gas-liquid separator and can extend to be connected with the air intake port of the compressor; the bottom part of the U-shaped bend section of the air outlet pipe is located in the liquid storage chamber, and an oil return port is provided on the bottom part of the U-shaped bend section, and the oil return port passes through the inner and outer walls of the bottom part of the U-shaped bend section so that the liquid in the liquid storage chamber can be sucked into the air outlet pipe through the oil return port.

[0033] In some embodiments,

[0034] The lower end of the return air pipe is vertically opposite to the air inlet end of the air outlet pipe of the U-shaped pipe structure, and the distance between the two is greater than a preset distance of 0. The return air pipe is a straight pipe, and its central axis coincides with the central axis of the air inlet end of the air outlet pipe and coincides with the central axis of the gas-liquid separator.

[0035] In some embodiments,

[0036] It also includes a fluorine pump, the lower end of the liquid outlet is also connected to a liquid outlet pipe, one end of the liquid outlet pipe is connected to the liquid storage chamber through the liquid outlet, and the other end is connected to the inlet end of the fluorine pump;

[0037] A liquid return port is also provided at the bottom of the gas-liquid separator, one end of the liquid return pipe is inserted into the liquid storage chamber of the gas-liquid separator through the liquid return port, and the other end is connected to the bottom of the gas collecting pipe.

[0038] In some embodiments,

[0039] The liquid outlet pipe is also provided with a one-way valve C, and the one-way valve C only allows the fluid to flow from the gas-liquid separator to the fluorine pump.

[0040] In some embodiments,

[0041] It also includes a liquid storage tank, a one-way valve A, an expansion valve, a fourth pipeline, a fifth pipeline and a sixth pipeline. The inlet end of the fluorine pump is also connected to the bottom end of the liquid storage tank through the fourth pipeline, and the outlet end of the fluorine pump is also connected to the evaporator through the fifth pipeline. The expansion valve is also arranged on the fifth pipeline. One end of the sixth pipeline is connected to the position between the liquid storage tank and the fluorine pump on the fourth pipeline, and the other end of the sixth pipeline is connected to the position between the fluorine pump and the expansion valve on the fifth pipeline; the outlet end of the condenser is connected to the inner top of the liquid storage tank through the seventh pipeline.

[0042] The automatic liquid return refrigeration system provided by the present invention has the following beneficial effects:

[0043] 1. The present invention provides a gas-liquid separator and a liquid return pipe, connects the liquid return pipe to the inner bottom of the evaporator or the inner bottom of the evaporator gas collecting pipe and the inside of the gas-liquid separator, and directly connects the liquid storage chamber at the bottom of the gas-liquid separator and the bottom port of the gas collecting pipe by using the liquid return pipe, so that the liquid at the bottom of the gas collecting pipe can directly flow to the bottom of the gas-liquid separator, which can effectively achieve the effect of guiding out the refrigerant liquid accumulated at the bottom of the evaporator or the bottom of the evaporator gas collecting pipe, so that it enters the gas-liquid separator and then enters the refrigeration system for circulation, and at the same time, through the gas return pipe connected to the gas-liquid separator, it is connected to the inside of the oil separator, so that the gas separated in the gas-liquid separator can be introduced into the oil separator The separator can also guide the liquid after gas-liquid separation at the bottom of the oil separator back to the gas-liquid separator through the return air pipe, thereby realizing secondary gas-liquid separation and ensuring that the refrigerant gas no longer carries the refrigerant liquid into the condenser, thereby avoiding liquid blockage and liquid seal on the gas pipeline; the refrigerant liquid separated for the second time in the oil separator forms a countercurrent with the rising gas in the pipeline along the pipeline wall under the action of gravity and returns to the gas-liquid separator again, effectively solving the problem of liquid accumulation in the middle and lower part of the evaporator and / or the middle and lower part of the gas collecting main pipe of the evaporator, resulting in too little refrigerant amount participating in the circulation in the system and affecting the heat exchange performance of the evaporator, and also solving the problem of liquid seal caused by liquid entering the condenser.

[0044] 2. The present invention also has a blocking structure arranged inside the gas-liquid separator, which interacts with the float below, and can divide the inside of the gas-liquid separator into an upper separation chamber and a lower liquid storage chamber, so that the gas-liquid mixture entering the separation chamber through the air inlet pipe is effectively separated into gas and liquid in the separation chamber, and the separated liquid enters the liquid storage chamber below through the connecting hole, and can be further discharged through the float at the liquid outlet, and the gas is led out of the gas-liquid separator through the return pipe (fluorine pump mode) or the air outlet pipe (compression mode). The blocking structure can effectively reduce the intensity of the upper airflow disturbing the liquid surface, thereby ensuring the normal operation of the float on the liquid surface and the normal function of liquid passage and gas blocking.

[0045] 3. The present invention also provides an air outlet pipe with a U-shaped tube structure, and an oil return port is provided on the bottom part of the bent section of the air outlet pipe. In the compression operation mode, the liquid in the liquid storage chamber can be sucked into the U-shaped tube through the oil return port, and then enters the compressor, thereby adding it to the refrigeration cycle system, further avoiding the situation where the amount of refrigerant and oil participating in the circulation is too small. In the fluorine pump refrigeration mode, the liquid in the liquid storage chamber gradually increases, thereby raising the float plug, and through the liquid outlet and the liquid outlet pipe, the liquid in the liquid storage chamber flows from the one-way valve C back to the suction port of the fluorine pump, thereby ensuring the refrigerant circulation amount of the refrigeration system.

[0046] 4. The present invention also makes the lower end of the return air pipe and the air inlet end of the air outlet pipe of the U-shaped pipe structure opposite to each other in the vertical direction, and the two are separated by a preset distance greater than 0, and the return air pipe is a straight pipe, and its central axis coincides with the central axis of the air inlet end of the air outlet pipe and the central axis of the gas-liquid separator, so that high-speed gas enters the gas-liquid separator from the air inlet pipe and rotates downward, and after contacting the wind baffle, it rebounds and flows upward along the central axis of the cylinder. Therefore, the air inlet end of the return air pipe and the U-shaped air outlet pipe are arranged on the central axis to meet the flow trend of the gas, so that more gas-liquid mixture contacts the baffle and the inner wall to complete gas-liquid separation, thereby further increasing the efficiency of gas-liquid separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a system principle diagram of the automatic liquid return refrigeration system of the present invention;

[0048] Figure 2 It is a front cross-sectional view of a gas-liquid separator of a refrigeration system with automatic liquid return according to the present invention;

[0049] Figure 3 yes Figure 2 A top view of the gas-liquid separator;

[0050] Figure 4 yes Figure 2 Top view of the blocking structure in .

[0051] The reference numerals are:

[0052] 1. Evaporator; 2. Gas-liquid separator; 3. Oil separator; 4. Liquid return pipe; 5. Air return pipe; 6. Blocking structure; 7. Air inlet pipe; 8. Separation chamber; 9. Liquid storage chamber; 10. Communication hole; 11. Compressor; 12. Air outlet pipe; 13. Air inlet; 14. Air return port; 15. Air outlet; 16. Air collecting pipe; 17. Oil return port; 18. One-way valve B; 19. Throttling device; 20. Fluorine pump; 21. Liquid outlet; 22. Liquid return port; 23. Liquid outlet pipe; 24. Float; 25. One-way valve C; 26. Liquid storage tank; 27. One-way valve A; 28. Expansion valve; 29. ​​Condenser; 30. Internal fan; 31. External fan;

[0053] 101, first pipeline; 102, second pipeline; 103, third pipeline; 104, fourth pipeline; 105, fifth pipeline; 106, sixth pipeline; 107, seventh pipeline. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0056] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0057] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0058] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0059] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0060] like Figure 1-4 As shown, the present invention provides a refrigeration system with automatic liquid return (preferably a fluorine pump compression double circulation system), which comprises:

[0061] An evaporator 1, a gas-liquid separator 2 and an oil separator 3, wherein the interior of the gas-liquid separator 2 is connected to the interior of the evaporator 1 through a liquid return pipe 4, so that the liquid inside the evaporator 1 can be led out to the gas-liquid separator 2;

[0062] It also includes a return air pipe 5, one end of which is connected to the interior of the gas-liquid separator 2, and the other end is connected to the interior of the oil separator 3, so that the gas separated inside the gas-liquid separator 2 can be introduced into the oil separator 3 through the return air pipe 5, and the liquid inside the oil separator 3 can be refluxed back to the gas-liquid separator 2 through the return air pipe 5.

[0063] The present invention provides a gas-liquid separator and a liquid return pipe, connects the liquid return pipe to the inner bottom of the evaporator or the inner bottom of the evaporator gas collecting pipe and the inside of the gas-liquid separator, and directly connects the liquid storage chamber at the bottom of the gas-liquid separator and the bottom port of the gas collecting pipe by using the liquid return pipe, so that the liquid at the bottom of the gas collecting pipe can flow directly to the bottom of the gas-liquid separator, and can effectively achieve the effect of guiding out the refrigerant liquid accumulated at the bottom of the evaporator or the bottom of the evaporator gas collecting pipe, so that it enters the gas-liquid separator and then enters the refrigeration system for circulation. At the same time, through the return pipe connected to the gas-liquid separator, it is connected to the inside of the oil separator, so that the gas separated in the gas-liquid separator can be introduced into the oil separator The separator can also guide the liquid after gas-liquid separation at the bottom of the oil separator back to the gas-liquid separator through the return air pipe to achieve secondary gas-liquid separation, ensuring that the refrigerant gas no longer carries the refrigerant liquid into the condenser, avoiding liquid blockage and liquid seal on the gas pipeline; the refrigerant liquid separated for the second time in the oil separator forms a countercurrent with the rising gas in the pipeline along the pipeline wall under the action of gravity and returns to the gas-liquid separator, effectively solving the problem of liquid accumulation in the middle and lower part of the evaporator and / or the middle and lower part of the gas collecting main pipe of the evaporator, resulting in too little refrigerant amount participating in the circulation in the system and affecting the heat exchange performance of the evaporator, and also solving the problem of liquid seal caused by liquid entering the condenser.

[0064] In some embodiments,

[0065] The return air pipe 5 is provided with a one-way valve B18, and the one-way valve B18 is configured to allow the air flow to only flow from the inside of the gas-liquid separator 2 to the oil separator 3, while allowing the liquid inside the oil separator 3 to flow back into the gas-liquid separator 2; the height of the bottom of the oil separator is higher than the height of the top of the gas-liquid separator, so that the liquid at the bottom of the oil separator 3 can automatically return to the gas-liquid separator 2 through the return air pipe 5 by gravity.

[0066] The present invention also allows the air flow to flow from the gas-liquid separator to the oil separator (fluorine pump mode) through the structural setting of the one-way valve B, and can also prevent the gas in the oil separator from flowing back to the gas-liquid separator through the oil separator and the return air pipe, especially in the compression mode. However, in the fluorine pump mode of the present invention, the one-way valve B is opened when the gas separated in the gas-liquid separator passes through the one-way valve B. At this time, the liquid at the bottom of the oil separator can flow back to the opened one-way valve B along the wall of the pipeline by gravity, and then further flow back to the gas-liquid separator through the bottom, forming a secondary separation effect, further improving the gas-liquid separation effect, ensuring that the gas entering the condenser is of higher purity, avoiding the phenomenon of liquid sealing caused by liquid entering the condenser, and avoiding the occurrence of a reduction in the heat exchange performance of the condenser; through the setting relationship between the oil separator and the height of the gas-liquid separator, the liquid at the bottom of the oil separator can automatically return to the gas-liquid separator, achieving the effect of automatic liquid return.

[0067] The present invention uses a liquid return pipe to directly connect the liquid storage chamber at the bottom of the gas-liquid separator and the bottom port of the gas collecting pipe, so that the liquid at the bottom of the gas collecting pipe can flow directly to the bottom of the gas-liquid separator. The multifunctional gas-liquid separator leads to an independent gas return port connected to the inlet of the one-way valve B, and the outlet of the one-way valve B is connected between the oil separator and the throttling device 19 (preferably an oil return capillary). In the fluorine pump refrigeration mode, the refrigerant at the outlet of the evaporator realizes the first gas-liquid separation in the gas-liquid separator, and after flowing out of the gas-liquid separator, it enters the oil separator through the one-way valve B to realize the second gas-liquid separation, thereby ensuring that the refrigerant gas no longer carries the refrigerant liquid into the condenser, avoiding the formation of liquid blockage and liquid seal on the gas pipeline; the refrigerant liquid separated for the second time in the oil separator forms a countercurrent with the rising gas in the pipeline along the pipeline wall under the action of gravity and returns to the gas-liquid separator.

[0068] The present invention solves the following technical problems:

[0069] 1. Liquid accumulation in the middle and lower part of the evaporator and / or the middle and lower part of the gas collecting main pipe of the evaporator;

[0070] 2. Liquid enters the condenser inlet, causing liquid blockage and liquid seal in the gas pipeline.

[0071] In some embodiments,

[0072] The oil separator 3 has oil of a first preset height in it, the return air pipe 5 is inserted into the interior of the oil separator 3 from the bottom of the oil separator 3, and the height of the return air pipe 5 inserted into the interior of the oil separator 3 does not exceed the height of the oil in the oil separator 3.

[0073] This is a further preferred structural form of the oil separator and the return air pipe of the present invention, that is, the return air pipe is preferably inserted into the oil separator at a height not exceeding the height of the oil, thereby ensuring that the liquid at the bottom of the oil separator is guided out, thereby improving the efficiency of returning liquid or oil.

[0074] In some embodiments,

[0075] It also includes a blocking structure 6 and a floating plug 24,

[0076] The blocking structure 6 is arranged in the gas-liquid separator 2, and the blocking structure 6 divides the internal cavity of the gas-liquid separator 2 into an upper cavity and a lower cavity, the upper cavity forms a separation chamber 8, and the lower cavity forms a liquid storage chamber 9. A communication hole 10 is provided through the blocking structure 6 from top to bottom and / or a communication hole 10 is formed between the blocking structure 6 and the inner wall of the gas-liquid separator 2, and the communication hole 10 connects the separation chamber 8 and the liquid storage chamber 9;

[0077] The bottom of the gas-liquid separator 2 is also provided with a liquid outlet 21, and the float 24 is arranged at the liquid outlet 21. At least part of the structure of the float 24 is located in the liquid storage chamber 9, and at least part of the structure is located in the liquid outlet 21 and the liquid outlet pipe 23. The float 24 can rise with the increase of the liquid level in the liquid storage chamber 9. When the liquid level in the liquid storage chamber 9 is greater than or equal to a second preset height, the float 24 is floated by the liquid and opens the liquid outlet 21. When the liquid level in the liquid storage chamber 9 is less than the second preset height, the float 24 falls due to its gravity and closes the liquid outlet 21.

[0078] The present invention also interacts with the float below through a blocking structure arranged inside the gas-liquid separator, and can divide the inside of the gas-liquid separator into an upper separation chamber and a lower liquid storage chamber, so that the gas-liquid mixture entering the separation chamber through the air inlet pipe is effectively separated into gas and liquid in the separation chamber, and the separated liquid enters the liquid storage chamber below through the connecting hole, and can be further discharged through the liquid outlet, and the gas is led out of the gas-liquid separator through the return pipe (fluorine pump mode) or the air outlet pipe (compression mode). The blocking structure can effectively reduce the intensity of the upper airflow disturbing the liquid surface, thereby ensuring the normal operation of the float on the liquid surface and ensuring the normal function of liquid passage and gas blocking.

[0079] The present invention designs a multifunctional gas-liquid separator, which adopts an upper and lower structure in which an upper gas-liquid separation chamber and a lower liquid storage chamber are connected, so as to reduce the intensity of the upper airflow disturbing the liquid surface and ensure the normal operation of the float on the liquid surface; a return liquid pipe is used to directly connect the liquid storage chamber at the bottom of the gas-liquid separator and the bottom port of the gas collecting pipe, so that the liquid at the bottom of the gas collecting pipe can directly flow to the bottom of the gas-liquid separator.

[0080] The problem of liquid accumulation at the bottom of the gas collecting pipe is effectively solved, so that the accumulated liquid can be quickly and effectively returned to the bottom liquid storage chamber of the gas-liquid separator, and then be sucked and ejected through the oil return hole of the gas-liquid separator in the compression refrigeration mode and returned to the compressor with the high-speed airflow, thereby ensuring the circulation volume of the system; in the fluorine pump refrigeration mode, the liquid in the liquid storage chamber gradually increases, thereby raising the float plug, and the liquid flows from the one-way valve C back to the suction port of the fluorine pump, thereby ensuring the circulation volume of the system. The multifunctional gas-liquid separator can realize gas-liquid separation, and the separated and stored liquid in various operating modes can continue to effectively participate in the circulation in the system without accumulating inside the gas-liquid separator.

[0081] The return pipe and the liquid outlet pipe of the present invention are preferably located in the liquid storage chamber with their pipe openings slightly higher than the inner bottom surface of the cylinder. A low-density float is also provided on the inner pipe opening of the liquid outlet pipe, and the density of the float is less than the density of the refrigerant liquid and / or the density of the lubricating oil and / or the mixed density of the oil-containing refrigerant liquid; the middle of the float is preferably a circular floating disk, and the upper and lower ends are slender cylindrical structures. The lower cylinder is inserted into the liquid outlet pipe and can float freely up and down (the diameter of the lower cylinder is smaller than the inner diameter of the liquid outlet pipe); when the top end of the upper cylinder hits the lower end surface of the wind shield, more than 1 / 2 of the lower cylinder is inserted into the liquid outlet pipe, thereby ensuring that the float will not fall out of the liquid outlet pipe.

[0082] In some embodiments,

[0083] The blocking structure 6 is a windshield structure, which can block at least part of the airflow in the separation chamber 8 from entering the liquid storage chamber 9. The gas-liquid separator 2 is a cylindrical structure with a central axis. The connecting hole 10 is arranged at a position closer to the inner wall of the gas-liquid separator 2 than the central axis. There are multiple connecting holes 10, and the multiple connecting holes 10 are arranged at intervals in the circumferential direction of the windshield.

[0084] This is the preferred structural form of the blocking structure of the present invention, that is, it is preferably a windshield structure, which separates the separation chamber and the liquid storage chamber to a certain extent, so that the liquid separated in the separation chamber can flow into the liquid storage chamber below through the connecting hole; the connecting hole is preferably arranged at a position close to the inner wall of the gas-liquid separator, so that most of the discharged liquid can be discharged, further improving the efficiency of gas-liquid separation; the connecting holes of the present invention are preferably multiple, and are arranged at intervals in the circumferential direction, which can increase the flow area, increase the downstream flow velocity and flow rate of the liquid, and further improve the efficiency of gas-liquid separation.

[0085] like Figure 2As shown, the present invention provides a multifunctional gas-liquid separator with a windshield, which consists of a cylindrical closed cylinder, an air inlet pipe, an air return pipe, a U-shaped air outlet pipe, a windshield, a liquid return pipe and a liquid outlet pipe. Various pipes are welded and sealed at the places where they pass through the cylinder, and the inner and outer sides of the cylinder are connected through inner and outer pipe openings; the gas-liquid separator is divided into a separation chamber and a liquid storage chamber in upper and lower parts by a horizontal windshield, and the windshield can reduce the impact of the violent high-speed rotating airflow in the upper part on the bottom liquid surface, thereby ensuring the stability of the liquid surface as much as possible, that is, ensuring the stability of the float on the liquid surface.

[0086] In the present invention, a small gap (forming a connecting hole 10) is preferably reserved between the wind shield and the inner wall of the cylinder. The preferred gap value is equivalent to the aperture of the filter screen arranged on the oil return port, so that larger solid particles in the upper separation chamber cannot pass through this gap into the lower liquid outlet chamber, thereby reducing solid impurities in the bottom liquid; the liquid separated in the upper separation chamber flows downward along the inner wall of the cylinder, passes through the small gap between the wind shield and flows into the liquid storage chamber at the bottom;

[0087] Alternatively, the side periphery of the windshield plate and the inner wall of the cylinder are fixed by interference fit, welding, or other limiting structures; in this case, the windshield plate and the inside of the cylinder are sealed without gaps, and a plurality of small-sized connecting holes 10 are arranged on the outer periphery of the windshield plate to connect the separation chambers and the liquid storage chambers on the upper and lower sides, so that the liquid separated in the upper separation chamber can enter the lower liquid storage chamber through these connecting holes.

[0088] In some embodiments,

[0089] It also includes an air inlet pipe 7, and the evaporator 1 also includes an air collecting pipe 16. The air collecting pipe 16 is located at the outlet end of the evaporator 1. One end of the air inlet pipe 7 is connected to the separation chamber 8, and the other end is connected to the air collecting pipe 16, so that the gas generated by the evaporator 1 can be introduced into the separation chamber 8. One end of the return pipe 4 is connected to the liquid storage chamber 9, and the other end is connected to the bottom of the air collecting pipe 16. One end of the return pipe 5 is connected to the separation chamber 8.

[0090] The present invention can collect the gas at the outlet end of the evaporator into one body through the gas collecting pipe for exhaust; the air inlet pipe is connected between the upper end of the gas collecting pipe and the separation chamber, and can lead the gas above the gas collecting pipe (gas-liquid mixture, containing more gas) to the gas-liquid separator for gas-liquid separation; the liquid return pipe is connected between the bottom of the gas collecting pipe and the liquid storage chamber, and can lead the accumulated liquid at the bottom of the gas collecting pipe to the liquid storage chamber, thereby reducing the situation of excessive liquid accumulation at the bottom of the gas collecting pipe and improving the refrigeration capacity of the system cycle; the gas return pipe is connected with the separation chamber, and can lead the separated gas to the oil separator to meet the refrigerant circulation supply in the fluorine pump mode.

[0091] The air inlet pipe of the present invention is located inside the cylinder and has a vertical bend and then connected to a horizontal pipe section, so that the vertically downward high-speed gas changes its flow direction to horizontal and flows horizontally along the tangent direction of the cylinder wall, and forms a high-speed rotating airflow after hitting the inner wall of the cylinder. The rotating airflow rotates downward along the wall, and the liquid carried by the high-speed gas is thrown onto the wall under the action of centrifugal force, flows downward along the wall and gathers at the bottom of the cylinder; the high-speed rotating downward gas flows downward, hits the wind shield and / or the bottom of the cylinder and / or the liquid surface at the bottom, then rebounds and flows upward along the central axis of the cylinder, and then flows out of the cylinder from the U-shaped air outlet pipe or the air return pipe, thereby completing the gas-liquid separation effect.

[0092] In some embodiments,

[0093] It also includes a compressor 11 and an air outlet pipe 12, one end of the air outlet pipe 12 is connected to the separation chamber 8 of the gas-liquid separator 2, and the other end can be connected to the air intake port of the compressor 11, so that the gas separated inside the gas-liquid separator 2 can be introduced into the compressor 11 through the air outlet pipe 12.

[0094] The present invention also adopts the setting of a compressor, which is connected to the separation chamber and the air intake of the compressor through an air outlet pipe, so that the gas separated by the gas-liquid separator can be guided to the compressor for compression, thereby ensuring the circulation of the refrigerant in the refrigeration cycle system in the compression mode.

[0095] In some embodiments,

[0096] It also includes a condenser 29, a first pipeline 101, a second pipeline 102 and a third pipeline 103. One end of the first pipeline 101 is connected to the air outlet of the compressor 11, and the other end is connected to the inner top of the oil separator 3. One end of the second pipeline 102 is connected to the inner top of the oil separator 3, and the other end is connected to one end of the condenser 29. One end of the third pipeline 103 is connected to the air outlet pipe 12, and the other end is connected to the return air pipe 5. The third pipeline 103 is provided with a throttling device 19.

[0097] The present invention also realizes the communication relationship between the compressor, the oil separator and the condenser through the arrangement of the condenser and the first to third pipelines, thereby ensuring that the gas at the compressor outlet first passes through the oil separator to separate the oil and then enters the condenser. Through the arrangement of the third pipeline, the oil can be returned to the compressor to ensure the normal demand for lubricating oil of the compressor, and the oil separator can guide the liquid inside the oil separator back to the gas-liquid separator through the return air pipe in the fluorine pump mode, thereby realizing secondary gas-liquid separation, improving the effect of gas-liquid separation, and further ensuring that the refrigerant entering the condenser is in a gaseous state, thereby avoiding the occurrence of liquid sealing.

[0098] In some embodiments,

[0099] An air inlet 13, an air return port 14 and an air outlet 15 are provided on the top plate of the gas-liquid separator 2; one end of the air inlet pipe 7 is inserted into the separation chamber 8 of the gas-liquid separator 2 through the air inlet 13, and the other end is connected to the interior of the collecting pipe 16; the air return pipe 5 is inserted into the separation chamber 8 of the gas-liquid separator 2 through the air return port 14, and the air outlet pipe 12 is inserted into the separation chamber 8 of the gas-liquid separator 2 through the air outlet 15.

[0100] This is a further preferred structural form of the gas-liquid separator of the present invention, that is, through the air inlet, air return port and air outlet arranged on the top thereof, it can be respectively inserted in conjunction with the air inlet pipe, air return pipe and air outlet pipe to ensure that the multiple pipes realize the connection between the separation chamber inside the gas-liquid separator and the gas collecting pipe, oil separator and compressor respectively.

[0101] In some embodiments,

[0102] The outlet pipe 12 is a U-shaped tube structure, one end of which is located in the separation chamber 8 so that fluid can be sucked in from the separation chamber 8, and the other end of the U-shaped tube passes through the top of the gas-liquid separator 2 and can extend to be connected to the suction port of the compressor 11; the bottom part of the U-shaped bend section of the outlet pipe 12 is located in the liquid storage chamber 9, and an oil return port 17 is provided on the bottom part of the U-shaped bend section, and the oil return port 17 passes through the inner and outer walls of the bottom part of the U-shaped bend section so that the liquid in the liquid storage chamber 9 can be sucked into the outlet pipe 12 through the oil return port 17.

[0103] This is the preferred structure of the air outlet pipe of the present invention. An oil return port is arranged on the bottom part of the bent section of the air outlet pipe, and the liquid in the liquid storage chamber can be sucked into the U-shaped tube through the oil return port in the compression operation mode, and then enters the compressor, thereby being added to the refrigeration cycle system, further avoiding the situation where the refrigerant and oil involved in the circulation are too small. In the fluorine pump refrigeration mode, the liquid in the liquid storage chamber gradually increases to raise the float plug, and the liquid in the liquid storage chamber flows back from the one-way valve C to the suction port of the fluorine pump through the liquid outlet and the liquid outlet pipe, thereby ensuring the refrigerant circulation amount of the refrigeration system.

[0104] The bent section at the bottom of the U-shaped air outlet pipe of the present invention is close to the bottom of the cylinder, and an oil return port is arranged on the side, and a filter screen is preferably arranged on the oil return port.

[0105] The windshield of the present invention is preferably sleeved on the U-shaped air outlet pipe, that is, at least two connecting holes are provided on the windshield, and the two ports of the U-shaped air outlet pipe can pass through the two connecting holes respectively, so that the windshield is clamped on the bending section at the bottom of the U-shaped air outlet pipe.

[0106] In some embodiments,

[0107] The lower end of the return air pipe 5 is vertically opposite to the air inlet end of the air outlet pipe 12 of the U-shaped tube structure, and the distance between the two is greater than a preset distance of 0. The return air pipe 5 is a straight pipe, and its central axis coincides with the central axis of the air inlet end of the air outlet pipe 12 and coincides with the central axis of the gas-liquid separator 2.

[0108] The present invention also places the lower end of the return air pipe and the air inlet end of the air outlet pipe of the U-shaped pipe structure opposite to each other in the vertical direction, and the two are separated by a preset distance greater than 0, and the return air pipe is a straight pipe, and its central axis coincides with the central axis of the air inlet end of the air outlet pipe and the central axis of the gas-liquid separator, so that high-speed gas enters the gas-liquid separator from the air inlet pipe and rotates downward, and after contacting the wind baffle, it rebounds and flows upward along the central axis of the cylinder. Therefore, the air inlet end of the return air pipe and the U-shaped air outlet pipe are arranged on the central axis to meet the flow trend of the gas, so that more gas-liquid mixture contacts the baffle and the inner wall to complete gas-liquid separation, thereby further increasing the efficiency of gas-liquid separation.

[0109] The U-shaped air outlet pipe of the present invention is preferably located at the inlet end inside the cylinder and the return pipe are both located on the vertical center axis of the cylinder. The air inlet ends of the two are located inside the cylinder and are vertically opposite but not connected. The reason for being located on the center axis is that high-speed gas enters the gas-liquid separator from the air inlet pipe and rotates downward, and after contacting the wind shield, it rebounds and flows upward along the center axis of the cylinder. Therefore, setting the air inlet ends of the return pipe and the U-shaped air outlet pipe on the center axis is in line with the flow trend of the gas.

[0110] In some embodiments,

[0111] It also includes a fluorine pump 20, and the lower end of the liquid outlet 21 is also connected to a liquid outlet pipe 23, one end of the liquid outlet pipe 23 is connected to the liquid storage chamber 9 through the liquid outlet 21, and the other end is connected to the inlet end of the fluorine pump 20;

[0112] The bottom of the gas-liquid separator 2 is also provided with a liquid return port 22 , one end of the liquid return pipe 4 is inserted into the liquid storage chamber 9 of the gas-liquid separator 2 through the liquid return port 22 , and the other end is connected to the bottom of the gas collecting pipe 16 .

[0113] This is a further preferred structural form of the present invention. Through the arrangement of the fluorine pump and the liquid outlet pipe, the liquid in the liquid storage chamber gradually increases in the fluorine pump refrigeration mode, thereby raising the float plug. Through the liquid outlet and the liquid outlet pipe, the liquid in the liquid storage chamber flows from the liquid outlet pipe back to the liquid suction port of the fluorine pump, thereby ensuring the refrigerant circulation volume of the refrigeration system; and a liquid return port is also arranged at the bottom of the gas-liquid separator, which can allow the liquid return pipe to be inserted, thereby ensuring the connection between the bottom of the gas collecting pipe and the liquid storage chamber, and ensuring the effect of draining out the liquid gathered at the bottom of the gas collecting pipe.

[0114] In some embodiments,

[0115] The liquid outlet pipe 23 is also provided with a one-way valve C25 , and the one-way valve C25 only allows the fluid to flow from the gas-liquid separator 2 to the fluorine pump 20 .

[0116] The present invention also ensures that the liquid separated from the liquid storage chamber of the gas-liquid separator can flow back to the fluorine pump through the provision of a one-way valve C, thereby ensuring the supply of refrigerant to the circulation system in the fluorine pump mode, and at the same time preventing the refrigerant between the inlet of the fluorine pump and the liquid storage tank from flowing back into the gas-liquid separator through the liquid outlet pipe, thereby avoiding the occurrence of a short circuit in the evaporator (this situation usually occurs in the compression mode).

[0117] The liquid in the liquid storage chamber of the present invention is sucked and injected through the oil return hole of the gas-liquid separator in the compression refrigeration mode and returns to the compressor together with the high-speed airflow. In the fluorine pump refrigeration mode, the liquid in the liquid storage chamber gradually increases to raise the float plug, and the liquid flows from the one-way valve C back to the liquid suction port of the fluorine pump, thereby ensuring the circulation volume of the system.

[0118] In some embodiments,

[0119] It also includes a liquid storage tank 26, a one-way valve A27, an expansion valve 28, a fourth pipeline 104, a fifth pipeline 105, a sixth pipeline 106 and a seventh pipeline 107. The inlet end of the fluorine pump 20 is also connected to the bottom end of the liquid storage tank 26 through the fourth pipeline 104, and the outlet end of the fluorine pump 20 is also connected to the evaporator 1 through the fifth pipeline 105. The expansion valve 28 is also provided on the fifth pipeline 105. One end of the sixth pipeline 106 is connected to the position between the liquid storage tank 26 and the fluorine pump 20 on the fourth pipeline 104, and the other end of the sixth pipeline 106 is connected to the position between the fluorine pump 20 and the expansion valve 28 on the fifth pipeline 105; the outlet end of the condenser 29 is connected to the inner top of the liquid storage tank 26 through the seventh pipeline 107.

[0120] The present invention also arranges a liquid storage tank, a one-way valve A, an expansion valve, and multiple pipelines so that the liquid storage tank can store refrigerant at a higher liquid level in the fluorine pump mode, ensuring that cavitation does not occur during the suction operation of the fluorine pump. The one-way valve A can effectively prevent the fluid at the outlet of the fluorine pump from flowing back to the inlet of the fluorine pump.

[0121] like Figure 1 As shown, the fluorine pump compression refrigeration system of the present invention is composed of a compressor, an oil separator, a condenser, a liquid storage tank, a fluorine pump, an expansion valve, an evaporator and a gas-liquid separator connected in sequence; a check valve A is connected in parallel to bypass the fluorine pump, and the flow direction of the check valve A is only allowed to be directed from the inlet of the fluorine pump to the outlet of the fluorine pump; a check valve B is connected in parallel to bypass the compressor, and the flow direction of the check valve B is only allowed to flow from the gas-liquid separator to the oil separator;

[0122] The one-way valve B is connected between the gas return port of the gas-liquid separator and the oil return port of the oil separator; further, the oil separator is arranged on the upper part of the gas-liquid separator, and the one-way valve B is connected in series on the connecting pipe between the two, and it is ensured that the pipe between the two has no convex and / or concave pipe section (bending is allowed), so as to ensure that the liquid in the oil separator can return to the gas-liquid separator below along the inner wall surface of the pipe under the action of gravity;

[0123] A throttling device 19 (preferably an oil return capillary tube) is connected between the oil return port of the oil separator and the air intake port of the compressor;

[0124] The upper middle part of the gas collecting pipe of the evaporator is connected to the gas inlet of the gas-liquid separator;

[0125] The bottom port of the gas collecting pipe of the evaporator is connected to the liquid return port of the gas-liquid separator through a liquid return pipe, so that the liquid accumulated at the bottom of the gas collecting pipe can flow directly to the bottom of the gas-liquid separator, thereby solving the problem of liquid accumulation in the middle and lower part of the evaporator and / or the gas collecting pipe;

[0126] The liquid outlet at the bottom of the gas-liquid separator is connected to the liquid suction port of the fluorine pump through a one-way valve C, and the flow direction of the one-way valve C only allows the flow from the gas-liquid separator to the liquid suction port of the fluorine pump.

[0127] Figure 1 In the medium compression refrigeration mode, the refrigerant cycle is: compressor → oil separator → condenser → liquid storage tank → check valve A → expansion valve → evaporator → gas-liquid separator → compressor. In this mode, the outlet of the check valve B is the high-temperature and high-pressure refrigerant gas and / or lubricating oil inside the oil separator, so the check valve B cannot be conducted and is in a reverse high-pressure cut-off closed state; the liquid in the liquid storage chamber at the bottom of the gas-liquid separator is sucked and ejected through the oil return hole of the gas-liquid separator in the compression refrigeration mode and returns to the suction port of the compressor together with the high-speed airflow, thereby ensuring the circulation volume of the system.

[0128] Figure 1In the fluorine pump refrigeration mode, the refrigerant cycle is: fluorine pump → expansion valve → evaporator → gas-liquid separator → one-way valve B → oil separator → condenser → liquid storage tank → fluorine pump. In this mode, the outlet pressure of the fluorine pump and the one-way valve A is relatively high, and the one-way valve A is in the reverse high-pressure cut-off closed state; the liquid in the liquid storage chamber at the bottom of the gas-liquid separator gradually increases in the fluorine pump refrigeration mode, thereby raising the float plug, and after the float plug rises, it opens the internal pipe mouth of the liquid outlet pipe, and the liquid in the liquid storage chamber flows out of the liquid outlet pipe and returns to the suction port of the fluorine pump through the one-way valve C, thereby ensuring the circulation volume of the system; because the multifunctional gas-liquid separator leads to an independent return port connected to the inlet of the one-way valve B, and the outlet of the one-way valve B is connected between the oil separator and the oil return capillary, in the fluorine pump refrigeration mode, the evaporator The refrigerant at the outlet of the condenser realizes the first gas-liquid separation in the gas-liquid separator. After the refrigerant gas flows out of the gas-liquid separator, it enters the oil separator through the one-way valve B to realize the second gas-liquid separation (the space in the oil separator suddenly becomes larger, causing the gas flow rate to drop sharply, which is helpful to achieve gas-liquid separation), thereby ensuring that the refrigerant gas flowing out of the oil separator no longer carries the refrigerant liquid into the condenser, avoiding the formation of liquid blockage and liquid seal on the gas pipeline; the refrigerant liquid separated for the second time in the oil separator forms a countercurrent with the rising gas in the pipeline along the pipeline wall under the action of gravity and returns to the gas-liquid separator.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A refrigeration system with automatic liquid return, characterized in that: include: An evaporator (1), a gas-liquid separator (2) and an oil separator (3), wherein the interior of the gas-liquid separator (2) is connected to the interior of the evaporator (1) via a liquid return pipe (4) so ​​that the liquid inside the evaporator (1) can be led into the gas-liquid separator (2); The invention also includes a return air pipe (5), one end of which is connected to the interior of the gas-liquid separator (2), and the other end of which is connected to the interior of the oil separator (3), so that the gas separated in the gas-liquid separator (2) can be introduced into the oil separator (3) through the return air pipe (5), and the liquid in the oil separator (3) can be returned to the gas-liquid separator (2) through the return air pipe (5).

2. The automatic liquid return refrigeration system according to claim 1, characterized in that: A one-way valve B (18) is provided on the return air pipe (5), and the one-way valve B (18) is configured to allow air flow only from the interior of the gas-liquid separator (2) to flow into the oil separator (3), while also allowing liquid inside the oil separator (3) to flow back into the gas-liquid separator (2); the bottom of the oil separator (3) is higher than the top of the gas-liquid separator (2), so that the liquid at the bottom of the oil separator (3) can automatically return to the gas-liquid separator (2) through the return air pipe (5) by gravity.

3. The automatic liquid return refrigeration system according to claim 1, characterized in that: The oil separator (3) contains oil at a first preset height, the return air pipe (5) is inserted into the interior of the oil separator (3) from the bottom of the oil separator (3), and the height of the return air pipe (5) inserted into the interior of the oil separator (3) does not exceed the height of the oil in the oil separator (3).

4. The automatic liquid return refrigeration system according to claim 1, characterized in that: Also includes a blocking structure (6) and a floating plug (24); The blocking structure (6) is arranged in the gas-liquid separator (2), and the blocking structure (6) divides the internal cavity of the gas-liquid separator (2) into an upper cavity and a lower cavity, the upper cavity forming a separation chamber (8), and the lower cavity forming a liquid storage chamber (9), and a communication hole (10) is provided through the blocking structure (6) from top to bottom and / or a communication hole (10) is formed between the blocking structure (6) and the inner wall of the gas-liquid separator (2), and the communication hole (10) connects the separation chamber (8) and the liquid storage chamber (9); The bottom of the gas-liquid separator (2) is further provided with a liquid outlet (21), and the float (24) is provided at the liquid outlet (21). At least part of the structure of the float (24) is located in the liquid storage chamber (9), and at least part of the structure is located in the liquid outlet (21). The float (24) can rise as the liquid level in the liquid storage chamber (9) rises. When the liquid level in the liquid storage chamber (9) is greater than or equal to a second preset height, the float (24) is floated by the liquid and opens the liquid outlet (21). When the liquid level in the liquid storage chamber (9) is less than the second preset height, the float (24) falls under its gravity and closes the liquid outlet (21).

5. The automatic liquid return refrigeration system according to claim 4, characterized in that: The blocking structure (6) is a windshield structure capable of blocking at least part of the airflow in the separation chamber (8) from entering the liquid storage chamber (9); the gas-liquid separator (2) is a cylindrical structure having a central axis; the connecting hole (10) is arranged at a position closer to the inner wall of the gas-liquid separator (2) than the central axis; there are a plurality of connecting holes (10), and the plurality of connecting holes (10) are spaced apart in the circumferential direction of the windshield.

6. The automatic liquid return refrigeration system according to claim 4 or 5, characterized in that: It also includes an air inlet pipe (7), and the evaporator (1) also includes an air collecting pipe (16). The air collecting pipe (16) is located at the outlet end of the evaporator (1). One end of the air inlet pipe (7) is connected to the separation chamber (8), and the other end is connected to the air collecting pipe (16), so that the gas generated by the evaporator (1) can be introduced into the separation chamber (8). One end of the return pipe (4) is connected to the liquid storage chamber (9), and the other end is connected to the bottom of the air collecting pipe (16). One end of the return pipe (5) is connected to the separation chamber (8).

7. The automatic liquid return refrigeration system according to claim 6, characterized in that: The invention also includes a compressor (11) and an air outlet pipe (12), one end of the air outlet pipe (12) is connected to the separation chamber (8) of the gas-liquid separator (2), and the other end can be connected to the air intake of the compressor (11), so that the gas separated inside the gas-liquid separator (2) can be introduced into the compressor (11) through the air outlet pipe (12).

8. The automatic liquid return refrigeration system according to claim 7, characterized in that: The utility model further comprises a condenser (29), a first pipeline (101), a second pipeline (102) and a third pipeline (103), wherein one end of the first pipeline (101) is connected to the air outlet of the compressor (11), and the other end is connected to the inner top of the oil separator (3); one end of the second pipeline (102) is connected to the inner top of the oil separator (3), and the other end is connected to one end of the condenser (29); one end of the third pipeline (103) is connected to the air outlet pipe (12), and the other end is connected to the air return pipe (5); and a throttling device (19) is provided on the third pipeline (103).

9. The automatic liquid return refrigeration system according to claim 7, characterized in that: An air inlet (13), an air return port (14) and an air outlet (15) are provided on the top plate of the gas-liquid separator (2); one end of the air inlet pipe (7) is inserted into the separation chamber (8) of the gas-liquid separator (2) through the air inlet (13), and the other end is connected to the interior of the gas collecting pipe (16); the air return pipe (5) is inserted into the separation chamber (8) of the gas-liquid separator (2) through the air return port (14), and the air outlet pipe (12) is inserted into the separation chamber (8) of the gas-liquid separator (2) through the air outlet (15).

10. The automatic liquid return refrigeration system according to claim 7, characterized in that: The outlet pipe (12) is a U-shaped pipe structure, one end of the U-shaped pipe is located in the separation chamber (8) so as to be able to suck fluid from the separation chamber (8), and the other end of the U-shaped pipe passes through the top of the gas-liquid separator (2) and can extend to be connected with the air intake of the compressor (11); the bottom part of the U-shaped bending section of the outlet pipe (12) is located in the liquid storage chamber (9), and an oil return port (17) is provided on the bottom part of the U-shaped bending section. The oil return port (17) passes through the inner and outer walls of the bottom part of the U-shaped bending section so as to be able to suck the liquid in the liquid storage chamber (9) into the outlet pipe (12) through the oil return port (17).

11. The automatic liquid return refrigeration system according to claim 10, characterized in that: The lower end of the return air pipe (5) is vertically opposite to the air inlet end of the air outlet pipe (12) of the U-shaped pipe structure, and the two are separated by a preset distance greater than 0. The return air pipe (5) is a straight pipe, and its central axis coincides with the central axis of the air inlet end of the air outlet pipe (12) and coincides with the central axis of the gas-liquid separator (2).

12. The automatic liquid return refrigeration system according to any one of claims 6 to 11, characterized in that: It also includes a fluorine pump (20), the lower end of the liquid outlet (21) is also connected to a liquid outlet pipe (23), one end of the liquid outlet pipe (23) is connected to the liquid storage chamber (9) through the liquid outlet (21), and the other end is connected to the inlet end of the fluorine pump (20); The bottom of the gas-liquid separator (2) is also provided with a liquid return port (22), one end of the liquid return pipe (4) is inserted into the liquid storage chamber (9) of the gas-liquid separator (2) through the liquid return port (22), and the other end is connected to the bottom of the gas collecting pipe (16).

13. The automatic liquid return refrigeration system according to claim 12, characterized in that: A one-way valve C (25) is also provided on the liquid outlet pipe (23), and the one-way valve C (25) only allows the fluid to flow from the gas-liquid separator (2) to the fluorine pump (20).

14. The automatic liquid return refrigeration system according to claim 12, characterized in that: The fluorine pump (20) further comprises a liquid storage tank (26), a one-way valve A (27), an expansion valve (28), a fourth pipeline (104), a fifth pipeline (105), a sixth pipeline (106) and a seventh pipeline (107). The inlet end of the fluorine pump (20) is further connected to the bottom end of the liquid storage tank (26) through the fourth pipeline (104), and the outlet end of the fluorine pump (20) is further connected to the evaporator (1) through the fifth pipeline (105). The fifth pipeline (105) also has a The expansion valve (28) is provided, one end of the sixth pipeline (106) is connected to the position between the liquid storage tank (26) and the fluorine pump (20) on the fourth pipeline (104), and the other end of the sixth pipeline (106) is connected to the position between the fluorine pump (20) and the expansion valve (28) on the fifth pipeline (105); the outlet end of the condenser (29) is connected to the inner top of the liquid storage tank (26) through the seventh pipeline (107).

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