Oil separator and preparation method therefor, refrigerant circulation loop, and heating, ventilation and air conditioning system

Abstract

Disclosed in the present application are an oil separator and a preparation method therefor, a refrigerant circulation loop, and a heating, ventilation and air conditioning system. The oil separator comprises a barrel and a gas output pipe. The barrel has an oil separation cavity and a mounting channel in communication with the oil separation cavity. The gas output pipe comprises a first branch pipe and a second branch pipe which are formed separately, wherein the first branch pipe is connected to the barrel and is at least partially located in the barrel; one end of the first branch pipe is connected to and in communication with one end of the second branch pipe in the mounting channel; part of the second branch pipe is located outside the barrel; and the joint of the first branch pipe and the second branch pipe is achieved by means of welding, and the first branch pipe is connected to the barrel by means of welding. The technical solution of the present application can reduce the costs of the oil separator and improve the reliability thereof.

Description

Oil separator and its preparation method, refrigerant circulation loop, HVAC system

[0001] This application claims priority to Chinese Patent Application No. 2024230333205, filed on December 9, 2024, entitled "Oil Separator and HVAC Equipment"; and to Chinese Patent Application No. 22025100552791, filed on January 13, 2025, entitled "Oil Separator and Preparation Method Thereof, Refrigerant Circulation Loop, HVAC System", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of heating, ventilation and air conditioning (HVAC) technology, and in particular to an oil separator and its preparation method, a refrigerant circulation loop, and an HVAC system. Background Technology

[0003] Some HVAC systems, such as air conditioners, use compressors to compress refrigerant gas to achieve cooling and heating functions. During operation, lubricating oil is needed to lubricate the internal components of the compressor, improving its service life and reliability. To reduce or prevent lubricating oil from entering the cooling and heating cycles with the refrigerant gas and affecting the equipment's performance and structural reliability, HVAC systems often have an oil separator connected to the compressor's discharge side to separate the oil contained in the refrigerant.

[0004] In related technologies, the reliability of pipeline connections in oil separators is not high. Summary of the Invention

[0005] This application provides an oil separator and its preparation method, a refrigerant circulation loop, and a heating, ventilation, and air conditioning system, which can reduce the cost of the oil separator and improve its reliability.

[0006] In a first aspect, embodiments of this application provide an oil separator, comprising:

[0007] A cylindrical body having an oil separation chamber and an installation channel communicating with the oil separation chamber; and

[0008] The vent pipe includes a first branch pipe and a second branch pipe formed separately. The first branch pipe is connected to the cylinder body and is at least partially located inside the cylinder body. One end of the first branch pipe and one end of the second branch pipe are connected and communicate with each other in the installation channel. A portion of the second branch pipe is located outside the cylinder body.

[0009] The first branch pipe and the second branch pipe are connected by welding, and the first branch pipe is also connected to the cylinder body by welding. This not only facilitates installation but also makes the connection between the first and second branch pipes, as well as the connection between the first branch pipe and the cylinder body, more secure and provides better sealing, reducing or preventing refrigerant leakage and improving the safety and reliability of the oil separator.

[0010] In one embodiment, the material of the first branch pipe is different from that of the second branch pipe.

[0011] In this embodiment, the vent pipe is configured as two parts: a first branch pipe and a second branch pipe, which are connected. The first branch pipe is located inside the cylinder and connected to it, while the second branch pipe is located outside the cylinder and connected to the first branch pipe. The second branch pipe is used to connect to the external piping of the HVAC system, and therefore uses a suitable material, such as copper. The first branch pipe does not need to be directly connected to external piping, so it can be made of a different material, such as steel, while still meeting the function of the vent pipe. It is understood that compared to related technologies where the vent pipe is a single, integral pipe made entirely of copper, the technical solution of this embodiment allows for different materials for the first and second branch pipes, which helps reduce costs.

[0012] In one embodiment, one end of the first branch pipe and one end of the second branch pipe are sleeved within the mounting channel. This improves the convenience and tightness of the connection between the first and second branch pipes.

[0013] In one embodiment, the portions of the first and second branch pipes that are interlocked are connected by welding. This welding method ensures a more secure connection between the first and second branch pipes, provides a better seal, and prevents leakage.

[0014] In one embodiment, the end of the first branch pipe is sleeved outside the end of the second branch pipe. This allows for easier assembly when the first and second branch pipes are first sleeved together and assembled into the cylinder.

[0015] In one embodiment, the projections of the second branch pipe onto the inner wall of the mounting channel and the projections of the first branch pipe onto the inner wall of the mounting channel overlap. The width of the overlapping portion along the axial direction of the mounting channel is h, satisfying the relationship 2mm ≤ h ≤ 15mm. Understandably, if h < 2mm, the welding length is insufficient, affecting the connection stability; if h > 15mm, the solder cannot completely cover the weld, affecting the welding effect. Therefore, to ensure welding effect and connection stability, this embodiment limits 2mm ≤ h ≤ 15mm.

[0016] In one embodiment, the first branch pipe is welded to the cylinder body; at least one of the outer wall of the first branch pipe and the inner wall of the mounting channel is provided with a protrusion to define a welding gap between the outer wall of the first branch pipe and the inner wall of the mounting channel. Thus, the welding of the first branch pipe to the cylinder body ensures high connection reliability. Furthermore, the first branch pipe, the second branch pipe, and the cylinder body can be connected in a single welding operation, reducing repetitive operations and improving production efficiency.

[0017] In one embodiment, the side wall of the cylinder is provided with a first through hole communicating with the oil separation chamber, and in the height direction of the oil separator, the end of the first branch pipe away from the second branch pipe is located below the first through hole;

[0018] The height difference between the end of the first branch pipe away from the second branch pipe and the axis of the first through hole is H1, and the height difference between the end of the first branch pipe away from the second branch pipe and the bottom of the oil separation chamber is H2, satisfying the relationship 0.1≤H1 / H2≤0.6, so as to ensure high oil separation efficiency.

[0019] In one embodiment, the side wall of the cylinder is provided with a first through hole communicating with the oil separation chamber, and the axis of the first through hole is spaced apart from the axis of the cylinder. In this way, the mixed fluid entering the oil separation chamber can form a spiral, facilitating the separation of oil droplets.

[0020] In one embodiment, an air inlet pipe is also included, which passes through the first through hole. The opening of one end of the air inlet pipe located in the oil separation chamber is inclined toward the first branch pipe. This is to avoid interference between the air inlet pipe and the first branch pipe, and to further make the mixed fluid entering the oil separation chamber flow spirally along the cylinder wall, thereby improving the oil separation efficiency.

[0021] In one embodiment, the inner diameter of the air intake pipe is d1, and the cylinder includes a main body section defining the oil separation chamber, the inner diameter of the main body section being d2, satisfying the relationship 1.5≤d2 / d1≤4, so as to improve the oil separation efficiency.

[0022] In one embodiment, the cylinder is further provided with an oil guide channel communicating with the oil separation chamber, and the oil guide channel is located at the bottom of the cylinder along the height direction of the oil separator;

[0023] The oil separator also includes a filter assembly located within the oil guide channel. This filter assembly filters out foreign matter, preventing blockages in subsequent pipelines.

[0024] In one embodiment, the filter assembly includes:

[0025] The substrate is fixed within the oil guiding channel and defines the oil outlet; and

[0026] A filter screen is connected to the substrate and covers the oil inlet. The filter screen arches towards the oil separation chamber relative to the substrate to increase the effective contact area between the filter screen and the oil, thereby improving the filtration effect.

[0027] In one embodiment, the system further includes a return oil pipe, one end of which is installed in the oil guide channel. The oil guide channel has a first limiting surface, and the substrate is sandwiched between the end of the return oil pipe and the first limiting surface for easy assembly.

[0028] In one embodiment, the substrate includes a filter screen fixing part surrounding the oil inlet, and the end face of the filter screen fixing part facing the first limiting surface is constructed as a second limiting surface, which abuts against the first limiting surface. In this way, the connection between the substrate and the filter screen is constructed as the second limiting surface. While ensuring the filtration function, there is no need to design the substrate in a lot, the structure is simple, and the cost is reduced.

[0029] Alternatively, along the axial direction of the oil guide channel, a second limiting surface is provided in the middle of the substrate, facing the first limiting surface, with the second limiting surface abutting against the first limiting surface. This allows the filter screen to extend as far into the oil separation chamber as possible, increasing the contact area between the filter screen and the oil, and improving the filtration effect.

[0030] In one embodiment, the return oil pipe is welded to the inner wall of the oil guide channel, resulting in high connection reliability and good sealing performance.

[0031] In one embodiment, the cylindrical body includes:

[0032] The main body section defines the oil separation chamber;

[0033] A first reduced-diameter section connects to one end of the main body section and defines the mounting channel; the inner diameter of the first reduced-diameter section is smaller than the inner diameter of the main body section.

[0034] The second reduced-diameter section connects to the end of the main body section away from the first reduced-diameter section and defines the oil guide channel. The inner diameter of the second reduced-diameter section is smaller than the inner diameter of the main body section.

[0035] This facilitates the connection and assembly of the cylinder with the oil return pipe and the air outlet pipe.

[0036] In one embodiment, the main body segment includes a first transition segment that connects to the first reduced-diameter segment, and the inner diameter of the first transition segment gradually decreases along the direction close to the first reduced-diameter segment. This creates a smooth transition between the main body segment and the first reduced-diameter segment, facilitating processing.

[0037] In one embodiment, the main body section includes a second transition section that connects to the second reduced-diameter section, and the inner diameter of the second transition section gradually decreases along the direction close to the reduced-diameter section. This not only facilitates the machining of the cylinder, but the second transition section also serves to collect oil and guide it through the oil guide channel, improving oil discharge efficiency.

[0038] In one embodiment, the cylinder is a single, integral component, offering good integrity and sealing, and facilitating manufacturing. And / or,

[0039] The outer diameter d3 of the main body section meets the condition 30mmn≤d3≤60mm, so as to make the cylinder smaller and ensure oil separation efficiency.

[0040] In one embodiment, it also includes an intake pipe and an oil return pipe;

[0041] The cylinder is made of steel and is provided with a first through hole, a second through hole and a third through hole;

[0042] The first end of the air intake pipe is inserted into the first through hole and welded to the cylinder body, and the second end of the air intake pipe is welded with a first copper connecting pipe, which is connected to the oil separation chamber through the air intake pipe.

[0043] The first end of the vent pipe is inserted into the second through hole and welded to the cylinder body. The second end of the vent pipe is welded with a second copper connecting pipe, which communicates with the oil separation chamber through the vent pipe.

[0044] The first end of the return oil pipe is inserted into the third through hole and welded to the cylinder body. The second end of the return oil pipe is welded with a third copper connecting pipe, which is connected to the oil separation chamber through the return oil pipe.

[0045] By welding a first copper connecting pipe, a second copper connecting pipe, and a third copper connecting pipe to the second end of the intake pipe, the second end of the exhaust pipe, and the second end of the oil return pipe, respectively, before connecting the oil separator to the compressor and other components via piping, a transition copper pipe can be welded to the connection end of the corresponding piping. Then, the first, second, and third copper connecting pipes are welded to their respective transition copper pipes. Welding between copper pipes is more convenient, and stable welding can be achieved through manual brazing or manual fusion welding. For brazing, flame welding or high-frequency welding techniques can be selected; for fusion welding, argon arc welding techniques can be selected. Furthermore, when the intake pipe, exhaust pipe, and oil return pipe are made of stainless steel or carbon steel, [the following text is incomplete and requires further context: "by..."] Since the oil separator is relatively small in size, the entire oil separator can be placed in a high-temperature furnace. The first, second, and third copper connecting pipes are then welded to the inlet pipe, outlet pipe, and return oil pipe respectively using a furnace welding process. When the steel and copper pipes are welded using the furnace welding process, the furnace contains hydrogen or hydrogen from the decomposition of ammonia in a high-temperature environment. Hydrogen is a reducing gas, which can reduce the oxide film on the outside of the steel pipe, allowing the steel and copper pipes to be brazed in the furnace. This ensures the welding stability of the first, second, and third copper connecting pipes to the inlet pipe, outlet pipe, and return oil pipe. Similarly, furnace welding can also be used when welding the transition copper pipes at the connection ends of the corresponding piping.

[0046] In some embodiments, the cylinder, the inlet pipe, the outlet pipe, and the return oil pipe are made of stainless steel or carbon steel. This can effectively reduce the cost of the oil separator and improve performance such as connection stability and vibration stress resistance. Furthermore, stainless steel has good corrosion resistance and can effectively resist the erosion of heat exchange media in environments with frequent heat exchange.

[0047] In some embodiments, the air inlet pipe, the air outlet pipe, and the oil return pipe are all welded steel pipes. Compared to seamless steel pipes, welded steel pipes are less expensive and easier to process and form.

[0048] In some embodiments, the inner diameter of the cylinder is d, where 19 mm ≤ d ≤ 89 mm. This prevents the oil separation efficiency of the oil separator from being too low due to a small oil separation chamber inside the cylinder, while also preventing the overall size of the machine from being too large due to an excessively large cylinder diameter.

[0049] In some embodiments, the first through hole is located on the circumferential side of the cylinder, and the axial length of the first through hole is H, where 1.2 mm ≤ H ≤ 7 mm. This prevents the flange length from being too small, which could lead to loosening after welding the air intake pipe, and also prevents the flange length from being too large, which could increase the volume of the oil separator.

[0050] In some embodiments, an arc transition surface is provided at the connection between the outer surface of the first through hole and the cylinder body, and the radius of the arc transition surface is R, where 0.2 mm ≤ R ≤ 1.2 mm. This achieves a smooth transition connection between the flange and the cylinder body, preventing breakage at the connection between the flange and the cylinder body.

[0051] In some embodiments, the axis of the first through hole is perpendicular to and does not intersect the axis of the cylinder. This allows the mixture of lubricating oil and heat exchange medium to have a tangential velocity when it enters the oil separator through the first through hole, while also extending the oil-gas separation path and prolonging the rotation time of the mixture within the cylinder, thereby improving the oil-gas separation effect.

[0052] In some embodiments, the cylindrical body includes a main body section, a first transition section, and a second transition section. The first transition section is located between the top end of the main body section and a second through hole, and the second through hole is connected to the first transition section. The second transition section is located between the bottom end of the main body section and a third through hole, and the third through hole is connected to the second transition section. Both the outer surfaces of the first and second transition sections are trumpet-shaped slopes. The angle between the outer surface of the first transition section and its axis is α1, where 30 degrees ≤ α1 ≤ 67.5 degrees. The angle between the outer surface of the second transition section and its axis is α2, where 30 degrees ≤ α2 ≤ 67.5 degrees. This design prevents the slopes of the outer surfaces of the first and second transition sections from being too large or too small.

[0053] In some embodiments, the air inlet pipe is inserted into the first through hole, the air outlet pipe is inserted into the second through hole, and the oil return pipe is inserted into the third through hole; wherein the insertion length of the air inlet pipe into the first through hole, the insertion length of the air outlet pipe into the second through hole, and the insertion length of the oil return pipe into the third through hole are L1, where 7 mm ≤ L1 ≤ 30 mm. This ensures that the air inlet pipe into the first through hole, the air outlet pipe into the second through hole, and the oil return pipe into the third through hole all have sufficient insertion length to guarantee weld penetration depth, thereby ensuring connection stability.

[0054] In some embodiments, the connection surfaces of the air inlet pipe and the first through hole, the air outlet pipe and the second through hole, and the oil return pipe and the third through hole are all provided with textured structures. This can effectively improve the corrosion resistance of the weld.

[0055] Secondly, this application also provides a method for preparing an oil separator, characterized in that it includes:

[0056] The two ends of the steel cylinder are spun and compressed to form a second and a third through hole;

[0057] The side of the cylinder is stamped to form the first through hole;

[0058] The first end of the air inlet pipe is inserted into the first through hole and welded to the cylinder body; the first end of the air outlet pipe is inserted into the second through hole and welded to the cylinder body; and the first end of the oil return pipe is inserted into the third through hole and welded to the cylinder body.

[0059] The first copper connecting pipe is welded to the second end of the air inlet pipe, the second copper connecting pipe is welded to the second end of the air outlet pipe, and the third copper connecting pipe is welded to the second end of the oil return pipe using a furnace welding process.

[0060] In some embodiments, the cylinder is made of stainless steel, and the steps of inserting the first end of the air inlet pipe into the first through hole and welding it to the cylinder, inserting the first end of the air outlet pipe into the second through hole and welding it to the cylinder, and inserting the first end of the oil return pipe into the third through hole and welding it to the cylinder include:

[0061] Insert the first end of the air inlet pipe into the first through hole, insert the first end of the air outlet pipe into the second through hole, and insert the first end of the oil return pipe into the third through hole.

[0062] The air inlet pipe, the air outlet pipe, and the oil return pipe are welded to the cylinder in a furnace using copper solder.

[0063] In some embodiments, the cylinder is characterized in that the cylinder body is made of carbon steel, and the steps of inserting the first end of the air inlet pipe into the first through hole and welding it to the cylinder body, inserting the first end of the air outlet pipe into the second through hole and welding it to the cylinder body, and inserting the first end of the oil return pipe into the third through hole and welding it to the cylinder body include:

[0064] Insert the first end of the air inlet pipe into the first through hole, insert the first end of the air outlet pipe into the second through hole, and insert the first end of the oil return pipe into the third through hole.

[0065] The air inlet pipe, the air outlet pipe, and the oil return pipe are welded to the cylinder in a furnace using copper solder.

[0066] An anti-corrosion layer is formed on the surface of the cylinder, at the weld between the air inlet pipe and the cylinder, at the weld between the air outlet pipe and the cylinder, and at the weld between the oil return pipe and the cylinder.

[0067] In some embodiments, the steps of welding the first copper connecting pipe to the second end of the intake pipe, welding the second copper connecting pipe to the second end of the exhaust pipe, and welding the third copper connecting pipe to the second end of the return oil pipe include:

[0068] The first copper connecting pipe is first welded to the air inlet pipe, the second copper connecting pipe is first welded to the air outlet pipe, and the third copper connecting pipe is first welded to the oil return pipe using tin bronze solder.

[0069] The first copper connecting pipe is welded to the inlet pipe, the second copper connecting pipe to the outlet pipe, and the third copper connecting pipe to the return oil pipe using copper solder in a furnace for a second welding.

[0070] Thirdly, this application also provides a refrigerant circulation loop, including a compressor, a four-way valve, a piping assembly, and an oil separator as described in any of the above embodiments. The oil separator further includes an inlet pipe and an oil return pipe communicating with the oil separation chamber. The inlet pipe is connected to the exhaust port of the compressor through the piping assembly, the exhaust pipe is connected to the first through hole of the four-way valve through the piping assembly, and the oil return pipe is connected to the first through hole of the compressor through the piping assembly.

[0071] Fourthly, this application also provides a heating, ventilation, and air conditioning system, including an outdoor unit and an indoor unit, wherein the outdoor unit includes a refrigerant circulation loop as described in any of the above embodiments, and the outdoor unit is connected to the indoor unit through the piping assembly. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0073] Figure 1 is a schematic diagram of an embodiment of the oil separator of this application;

[0074] Figure 2 is a schematic cross-sectional view of the oil separator in Figure 1 at section AA.

[0075] Figure 3 is an enlarged structural schematic diagram of the connection between the first and second branch pipes in this application;

[0076] Figure 4 is a top view of the cross-sectional structure of an embodiment of the oil separator of this application;

[0077] Figure 5 is a schematic diagram of the structure at point B in Figure 2;

[0078] Figure 6 is a top view of a structural schematic diagram of an embodiment of the filter assembly of this application;

[0079] Figure 7 is a schematic cross-sectional view of the filter assembly at interface CC in Figure 6.

[0080] Figure 8 is a cross-sectional structural diagram of another embodiment of the filter assembly in Figure 6 at interface CC;

[0081] Figure 9 is a schematic diagram of the structure of an oil separator in one embodiment of this application;

[0082] Figure 10 is a structural schematic diagram of the cylinder from a first perspective in an embodiment of this application;

[0083] Figure 11 is a structural schematic diagram of the cylinder from a second perspective in an embodiment of this application;

[0084] Figure 12 is a schematic diagram of the structure of the cylinder, air outlet pipe, oil return pipe and filter assembly in one embodiment of this application;

[0085] Figure 13 is an enlarged view of point D in Figure 12;

[0086] Figure 14 is an enlarged view of point E in Figure 12;

[0087] Figure 15 is a partial structural schematic diagram of an oil separator in one embodiment of this application;

[0088] Figure 16 is an enlarged schematic diagram of point F in Figure 15;

[0089] Figure 17 is an enlarged schematic diagram of point G in Figure 15;

[0090] Figure 18 is a schematic diagram of the preparation process of the refrigerant circulation loop in one embodiment of this application;

[0091] Figure 19 is a schematic diagram of the refrigerant circulation loop in one embodiment of this application;

[0092] Figure 20 is a schematic diagram of the structure of a heating, ventilation and air conditioning system according to an embodiment of this application.

[0093] Reference numerals: 100, Oil separator; 10, Cylinder; 11, Main body section; 111, First transition section; 113, Second transition section; 115, Oil separation chamber; 117, First through hole; 118, Second through hole; 119, Third through hole; 13, First diameter reduction section; 131, Installation channel; 15, Second diameter reduction section; 151, Oil guide channel; 153, First limiting surface; 16, First copper connecting pipe; 17, Second copper connecting pipe; 18, ... Three copper connecting pipes; 30, exhaust pipe-exhaust pipe; 31, first branch pipe; 311, welding gap; 33, second branch pipe; 50, intake pipe; 70, oil return pipe-oil return pipe; 90, filter assembly; 91, base; 911, second limiting surface; 93, filter; 200, outdoor unit; 210, compressor; 220, four-way valve; 230, piping assembly; 240, gas-liquid separator; 250, heat exchanger; 300, indoor unit.

[0094] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0095] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0096] Where the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0097] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0098] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0099] One aspect of this application provides a heating, ventilation, or air conditioning system, which is used for heating, ventilation, or air conditioning, such as an air conditioner.

[0100] In some embodiments, the HVAC system includes a compressor, a condenser, an expansion valve, an evaporator, and an oil separator. The compressor compresses refrigerant, which then exchanges heat with air and condenses in the condenser. The condensed refrigerant flows through the expansion valve and expands, exchanging heat with air and evaporating. Optionally, when the HVAC system operates as a cooler, the evaporator may correspond to an indoor heat exchanger located in the indoor space, and the condenser may correspond to an outdoor heat exchanger located in the outdoor space; when the HVAC system operates as a heater, the evaporator may correspond to an outdoor heat exchanger located in the outdoor space, and the condenser may correspond to an indoor heat exchanger located in the indoor space.

[0101] In one embodiment, as shown in FIG20, the HVAC system includes an outdoor unit 200 and an indoor unit 300. The outdoor unit 200 includes a refrigerant circulation loop as in any of the above embodiments, and the outdoor unit 200 is connected to the indoor unit 300 through a piping assembly 230.

[0102] As shown in Figure 19, the refrigerant circulation loop includes a compressor 210, a four-way valve 220, a piping assembly 230, and an oil separator 100 as described in any of the above embodiments. The first copper connecting pipe 16 is connected to the exhaust port of the compressor 210 through the piping assembly 230, the second copper connecting pipe 17 is connected to the first through hole of the four-way valve 220 through the piping assembly 230, and the third copper connecting pipe 18 is connected to the first through hole of the compressor 210 through the piping assembly 230.

[0103] When the compressor 210 discharges, the lubricating oil in the compressor 210 is mixed with the heat exchange medium and discharged from the discharge port of the compressor 210. Then, it is discharged into the oil separation chamber 115 through the piping assembly 230, the first copper connecting pipe 16 and the intake pipe 50. The oil separator 100 separates the heat exchange medium and the lubricating oil. The heat exchange medium flows through the outlet pipe 30 and the second copper connecting pipe 17 to the first through hole of the four-way valve 220, and can flow to the heat exchanger 250 and other devices connected to the outlet of the four-way valve 220. The lubricating oil returns to the gas-liquid separator 240 or the compressor 210 through the return oil pipe 70 and the third copper connecting pipe 18.

[0104] During compressor operation, lubricating oil is required to lubricate the internal components, improving the compressor's lifespan and reliability. To reduce or prevent lubricating oil from entering the refrigeration and heating cycles with the refrigerant gas, thus affecting the HVAC system's performance and structural reliability, an oil separator is connected between the compressor and the condenser to separate the oil contained in the refrigerant. In related technologies, the refrigerant outlet pipe in the oil separator is made entirely of copper for connection to external piping. This undoubtedly increases costs during mass production and is detrimental to economic efficiency.

[0105] This application provides an oil separator 100. Referring to Figures 1 and 2, in some embodiments, the oil separator 100 includes a cylinder 10, an inlet pipe 50, an outlet pipe 30, and an oil return pipe 70. The inlet pipe 50, outlet pipe 30, and oil return pipe 70 are all connected to the cylinder 10. The inlet pipe 50 is used to introduce refrigerant into the cylinder 10, where the refrigerant undergoes an oil droplet separation process. The outlet pipe 30 is used to discharge the refrigerant after oil droplet separation to an external pipeline. The oil return pipe 70 is used to discharge the oil droplets separated from the refrigerant from the cylinder 10.

[0106] Optionally, the cylinder 10 is made of metal and is generally cylindrical. For example, the cylinder 10 can be made of stainless steel or carbon steel. In particular, when using carbon steel, an anti-rust coating is applied to the outer surface of the cylinder 10 to prevent rusting. The cylinder 10 has an oil separation chamber 115 inside, and one end of the cylinder 10 along its axial direction has an installation channel 131 communicating with the oil separation chamber 115. A portion of the vent pipe 30 is disposed within the installation channel 131. The vent pipe 30 includes a first branch pipe 31 and a second branch pipe 33, both of which can be selected as pipes with a circular cross-section. The first branch pipe 31 is connected to the cylinder 10 and is at least partially located inside the cylinder 10. One end of the first branch pipe 31 and one end of the second branch pipe 33 are connected and communicate within the installation channel 131. A portion of the second branch pipe 33 is located outside the cylinder 10 for communication with external pipelines. In this embodiment, the materials of the first branch pipe 31 and the second branch pipe 33 are different. For example, the first branch pipe 31 is a steel pipe, specifically a stainless steel pipe or a carbon steel pipe, and the second branch pipe 33 is a copper pipe, such as a copper pipe, so as to facilitate connection with an external pipe that is also made of copper.

[0107] In other words, in this embodiment, the vent pipe 30 is configured as two parts: a first branch pipe 31 and a second branch pipe 33. The first branch pipe 31 and the second branch pipe 33 are connected. The first branch pipe 31 is located inside and connected to the cylinder 10, while the second branch pipe 33 is located outside the cylinder 10 and connected to the first branch pipe 31. The second branch pipe 33 is used to connect to the external piping of the HVAC system, and therefore uses a suitable material, such as copper. The first branch pipe 31 does not need to be directly connected to external pipes, so, provided that the function of the vent pipe 30 is met, the first branch pipe 31 can be made of a different material, such as steel. It is understandable that, compared to related technologies where the vent pipe 30 is a single, integral pipe made entirely of copper, the technical solution of this embodiment allows for different materials for the first branch pipe 31 and the second branch pipe 33 of the vent pipe 30, which helps to reduce costs.

[0108] In addition, the first branch pipe 31 and the second branch pipe 33 are connected in the installation channel 131, which not only facilitates installation, but also reduces or avoids refrigerant leakage and improves the safety and reliability of the oil separator 100.

[0109] Referring to Figure 3, in one embodiment, one end of the first branch pipe 31 and one end of the second branch pipe 33 are sleeved within the mounting channel 131. In the illustrated embodiment, the upper end of the first branch pipe 31 along its own axial direction is sleeved with the lower end of the second branch pipe 33 along its own axial direction. This makes it easier to align and connect the first branch pipe 31 and the second branch pipe 33. Furthermore, the sleeved structure at the connection point of the first branch pipe 31 and the second branch pipe 33 can prevent refrigerant leakage, improve the tightness of the connection between the first branch pipe 31 and the second branch pipe 33, and improve the sealing effect of the outlet pipe 30.

[0110] The first branch pipe 31 is welded to the cylinder 10 to ensure stable fixation of the first branch pipe 31 within the mounting channel 131, resulting in a high connection reliability. Specifically, at least one of the outer wall of the first branch pipe 31 and the inner wall of the mounting channel 131 has a protrusion to define a welding gap 311 between them. For example, if the outer wall of the first branch pipe 31 has a protrusion, during assembly, after inserting the first branch pipe 31 into the mounting channel 131, the protrusion abuts against the inner wall of the mounting channel 131, facilitating pre-positioning before welding. Except for the portion of the outer wall surface of the first branch pipe 31 that abuts against the inner wall of the mounting channel 131, the remaining outer wall surface defines a welding gap 311 between the first branch pipe 31 and the inner wall of the mounting channel 131 for filling with solder. Optionally, the protrusion is an elongated strip extending approximately axially along the first branch pipe 31 to extend the width of the welding gap 311 in the axial direction of the first branch pipe 31, thereby increasing the welding strength. The protrusions are multiple and spaced apart circumferentially along the first branch pipe 31 to ensure more uniform solder distribution. Of course, the shape of the protrusions is not limited in this embodiment; in other embodiments, the protrusions may be spherical or similar, and may also be located on the inner wall of the mounting channel 131. It is understood that placing the protrusions on the first branch pipe 31 is easier to process than placing them on the inner wall of the mounting channel 131, thus improving production efficiency.

[0111] The portion where the first branch pipe 31 and the second branch pipe 33 interlock is also connected by welding. In this way, welding makes the connection between the first branch pipe 31 and the second branch pipe 33 more secure, provides better sealing, and prevents refrigerant leakage.

[0112] Furthermore, the end of the first branch pipe 31 is fitted over the end of the second branch pipe 33. As shown in Figure 3, the upper end of the first branch pipe 31 along its own axial direction has a flared section, the inner diameter of which is larger than the inner diameter of the rest of the first branch pipe 31. The flared section is fitted over the lower end of the second branch pipe 33 along its own axial direction. In this way, the inner diameter of the second branch pipe 33 can be the same as the inner diameter of the first branch pipe 31 excluding the flared section, so as to ensure the consistency of the inner diameter of the parts of the first branch pipe 31 and the second branch pipe 33 used for refrigerant flow, thereby ensuring smooth refrigerant flow and improving the sealing of the outlet pipe 30 to prevent refrigerant leakage. During assembly, the first branch pipe 31 and the second branch pipe 33 can be fitted together first and then installed into the installation channel 131 together, reducing the docking operation. During welding, the solder enters the welding gap 311 from the opening at the end of the installation channel 131 away from the oil separation chamber 115. Since the end of the first branch pipe 31 is sleeved outside the end of the second branch pipe 33, the gap between the end of the first branch pipe 31 and the end of the second branch pipe 33 can also be exposed upwards. The solder can fill the welding gap 311 and the gap between the end of the first branch pipe 31 and the end of the second branch pipe 33 in one go, thereby completing the welding of the first branch pipe 31 to the cylinder 10 and the welding of the first branch pipe 31 and the second branch pipe 33 in one go, reducing repetitive operations and improving welding efficiency and production efficiency.

[0113] In one embodiment, the projections of the second branch pipe 33 onto the inner wall of the mounting channel 131 and the first branch pipe 31 onto the inner wall of the mounting channel 131 overlap. The width of the overlapping portion along the axial direction of the mounting channel 131 is h, satisfying the relationship 2mm ≤ h ≤ 15mm. Understandably, if h < 2mm, the welding length of the first branch pipe 31 and the second branch pipe 33 is insufficient, affecting the connection stability of the first branch pipe 31 and the second branch pipe 33; if h > 15mm, the solder cannot completely cover the gap between the first branch pipe 31 and the second branch pipe 33, affecting the welding effect. Therefore, to ensure welding effect and connection stability, this embodiment limits 2mm ≤ h ≤ 15mm. Optionally, h can be 7mm, 9mm, 12mm, 15mm, etc.

[0114] Referring to Figures 2 and 4, in one embodiment, the side wall of the cylinder 10 is provided with a first through hole 117 communicating with the oil separation chamber 115. The intake pipe 50 passes through the first through hole 117 so that the internal flow channel of the intake pipe 50 communicates with the oil separation chamber 115. In the height direction (axial direction of the cylinder 10) of the oil separator 100, the end of the first branch pipe 31 away from the second branch pipe 33 is located below the first through hole 117, preventing the refrigerant flowing from the intake pipe 50 into the cylinder 10 from directly flowing into the first branch pipe 31. Further, the height difference between the end of the first branch pipe 31 away from the second branch pipe 33 and the axis of the first through hole 117 is H1, and the height difference between the end of the first branch pipe 31 away from the second branch pipe 33 and the bottom of the oil separation chamber 115 is H2, satisfying the relationship 0.1≤H1 / H2≤0.6. Understandably, if H1 / H2 is greater than 0.6, it indicates that the distance between the end of the first branch pipe 31 furthest from the second branch pipe 33 and the axis of the first through hole 117 is too great. The end of the first branch pipe 31 furthest from the second branch pipe 33 is closer to the bottom of the oil separation chamber 115, which may cause oil backflow or blockage of the first branch pipe 31, making it difficult for refrigerant to flow. If H1 / H2 is less than 0.1, it may cause the refrigerant flowing from the inlet pipe 50 into the cylinder 10 to flow directly into the first branch pipe 31, resulting in poor oil separation. Therefore, to ensure high oil separation efficiency, this application embodiment limits 0.1 ≤ H1 / H2 ≤ 0.6, and H1 / H2 can be selected as 0.3, 0.4, 0.6, etc.

[0115] In one embodiment, the axis of the first through hole 117 is spaced apart from the axis of the cylinder 10, and the air inlet pipe 50 passes through the first through hole 117 along its axis. Thus, the mixed fluid (a mixture of refrigerant and oil) flowing into the oil separation chamber 115 from the first through hole 117 impacts the inner wall of the oil separation chamber 115 and forms a spiral under the guidance of the inner wall, facilitating the separation of oil droplets from the mixed fluid.

[0116] In some embodiments, the axis O2 of the first through hole 117 is perpendicular to and does not intersect with the axis O1 of the cylinder 10, such that the axis O2 of the first through hole 117 is eccentrically set relative to the axis O1 of the cylinder 10. This allows the mixture formed by the lubricating oil and heat exchange medium of the compressor 210 to enter the oil separation chamber 115 along the first through hole 117. When the mixture enters the oil separator 100 along the first through hole 117, it has a tangential velocity, which allows the mixture to rotate inside the cylinder 10. This enables the mixture to achieve oil-gas separation through centrifugal force, preventing the mixture from directly colliding with the cylinder 10, reducing kinetic energy loss, and accelerating the oil-gas separation speed. Furthermore, there is a certain distance between the mixture and the axis O1 of the cylinder 10, which prolongs the oil-gas separation path and extends the rotation time of the mixture inside the cylinder 10, thereby improving the oil-gas separation effect.

[0117] Furthermore, referring to Figure 4, the intake pipe 50 is located on one side of the first branch pipe 31. Specifically, from the perspective shown in Figure 4, the intake pipe 50 is located below the first branch pipe 31, and the opening of one end of the intake pipe 50 within the oil separation chamber 115 is inclined towards the first branch pipe 31. Understandably, the inclined opening of the intake pipe 50 within the oil separation chamber 115 reduces the amount of material near the first branch pipe 31, thus avoiding interference between the intake pipe 50 and the first branch pipe 31. In addition, the inclined opening can guide the mixed fluid entering the oil separation chamber 115 towards the inner wall of the oil separation chamber 115, causing it to flow spirally along the inner wall of the oil separation chamber 115, thereby improving oil separation efficiency.

[0118] In one embodiment, the inner diameter of the air inlet pipe 50 is d1, and the cylinder 10 includes a main body section 11 that defines the oil separation chamber 115. Specifically, the main body section 11 includes a cylinder 10 structure with a first through hole 117, the specific structural range of which will be described in subsequent embodiments. In this embodiment, the inner diameter of the main body section 11 is d2, satisfying the relationship 1.5 ≤ d2 / d1 ≤ 4, to ensure the flow velocity of the fluid along the inner wall of the oil separation chamber 115 and improve oil separation efficiency.

[0119] During the rotation of the fluid along the inner wall of the oil separation chamber 115, the separated oil is deposited at the bottom of the oil separation chamber 115. Referring to Figures 2 and 5, to prevent oil accumulation, in some embodiments, the cylinder 10 is also provided with an oil guide channel 151 communicating with the oil separation chamber 115. The oil guide channel 151 is located at the bottom of the cylinder 10 along the height direction of the oil separator 100, and is used to guide the oil at the bottom of the oil separation chamber 115 through the oil guide channel 151. The oil separator 100 in this embodiment also includes a filter assembly 90, which is located inside the oil guide channel 151. The filter assembly 90 can filter foreign objects, preventing foreign objects from flowing into other subsequent pipelines and causing blockage, thus ensuring the smooth flow of the flow path.

[0120] In one specific embodiment, the filter assembly 90 includes a substrate 91 and a filter screen 93. The substrate 91 is fixed within the oil channel 151 to form the connection base for the filter screen 93. The substrate 91 defines an oil passage. The filter screen 93 is connected to the substrate 91 and covers the oil passage. The substrate 91 may optionally be annular, with the oil passage defined in the middle portion of the substrate 91 to facilitate oil flow. The filter screen 93 and the substrate 91 may be welded together. The filter screen 93 arches towards the oil separation chamber 115 relative to the substrate 91, thereby increasing the effective contact area between the filter screen 93 and the oil, improving the filtration effect of the filter assembly 90 on foreign matter, and effectively preventing pipeline blockage.

[0121] Referring to Figures 2 and 5, in one embodiment, one end of the oil return pipe 70 is installed inside the oil guide channel 151 to guide the oil within the oil guide channel 151 to an external pipeline. For example, the other end of the oil return pipe 70 can be connected to a compressor to recover and reuse the separated oil, ensuring smooth compressor operation while improving oil utilization efficiency and avoiding waste. Optionally, the end of the oil return pipe 70 located inside the oil guide channel 151 is welded to the inner wall of the oil guide channel 151, ensuring high connection reliability and good sealing.

[0122] In this embodiment, the oil guide channel 151 is provided with a first limiting surface 153. The base 91 is sandwiched between the end of the return oil pipe 70 located in the oil guide channel 151 and the first limiting surface 153. Thus, during the assembly process, after the base 91 is placed into the installation channel 131, the return oil pipe 70 can be connected so that the base 91 can be fixed by the end of the return oil pipe 70 and the first limiting surface 153. The assembly is convenient, fast and efficient.

[0123] Referring to Figures 5 to 7, in one embodiment, the substrate 91 includes a filter screen 93 fixing portion surrounding the oil inlet. The end face of the filter screen 93 fixing portion facing the first limiting surface 153 is configured as a second limiting surface 911, and the second limiting surface 911 abuts against the first limiting surface 153. In this embodiment, the connection between the substrate 91 and the filter screen 93 is configured as the second limiting surface 911. While ensuring the filtration function, no excessive design is required for the substrate 91, resulting in a simple structure and reduced costs.

[0124] Referring to Figures 5, 6, and 8, in another embodiment, along the axial direction of the oil guide channel 151, the middle part of the substrate 91 is provided with a second limiting surface 911 facing the first limiting surface 153, and the second limiting surface 911 abuts against the first limiting surface 153. This allows the filter screen 93 to extend into the oil separation chamber 115 as much as possible, increasing the contact area between the filter screen 93 and the oil, and improving the filtration effect.

[0125] Referring to Figures 1 and 2, in some embodiments, the cylinder 10 includes a main body section 11, a first reduced-diameter section 13, and a second reduced-diameter section 15. The first reduced-diameter section 13 and the second reduced-diameter section 15 are located at opposite ends of the main body section 11 along its axial direction. The inner diameter of the first reduced-diameter section 13 is smaller than the inner diameter of the main body section 11, and the inner diameter of the second reduced-diameter section 15 is smaller than the inner diameter of the main body section 11. The main body section 11 defines an oil separation chamber 115, the first reduced-diameter section 13 defines the aforementioned installation channel 131, and the second reduced-diameter section 15 defines the aforementioned oil guiding channel 151. This ensures that the main body section 11 has sufficient dimensions for refrigerant flow and facilitates the connection and assembly of the cylinder 10 with the oil return pipe 70 and the gas outlet pipe 30.

[0126] Optionally, the main body section 11 includes a first transition section 111, which connects to the first reduced-diameter section 13. The inner diameter of the first transition section 111 gradually decreases along the direction approaching the first reduced-diameter section 13. This allows for a smooth transition between the main body section 11 and the first reduced-diameter section 13, facilitating machining. The main body section 11 may also include a second transition section 113, which connects to the second reduced-diameter section 15. The inner diameter of the second transition section 113 gradually decreases along the direction approaching the second reduced-diameter section 15. This not only facilitates machining of the cylinder 10, but the second transition section 113 also collects oil and guides it to the oil guide channel 151, improving oil discharge efficiency. The main body section 11 may have either the first transition section 111 or the second transition section 113 alone, or both may be provided simultaneously to ensure a smooth transition between the main body section 11 and the first reduced-diameter section 13 and the second reduced-diameter section 15, thereby improving oil discharge efficiency.

[0127] In this embodiment, the outer diameter d3 of the main body section 11 satisfies the condition 30mmn≤d3≤60mm. Understandably, if the outer diameter d3 is greater than 60mm, the fluid entering the main body section 11 will experience a significant decrease in flow velocity along its inner wall, which is detrimental to oil droplet separation. Conversely, if the outer diameter d3 is less than 30mm, the oil droplet separation efficiency will be poor. This application embodiment limits the outer diameter d3 to meet the condition 30mmn≤d3≤60mm to achieve miniaturization of the cylinder 10 and ensure oil separation efficiency. The outer diameter d3 can be selected as 40mm, 50mm, or 60mm.

[0128] Furthermore, the cylinder 10 is a single integral component, that is, the main body section 11, the first reduced diameter section 13, and the second reduced diameter section 15 are integrally formed, which has good integrity and sealing performance, and is easy to manufacture and process. Of course, the main body section 11, the first reduced diameter section 13, and the second reduced diameter section 15 can also be processed and formed separately and then welded to form the cylinder 10, and this application embodiment does not limit this.

[0129] When welding oil separators with compressors and other components to assemble the whole machine, the large size of the whole machine makes it difficult to place it in a high-temperature furnace for welding. In order to control raw material costs, the piping connecting the oil separator and compressors is mostly made of stainless steel. Due to the limitations of stainless steel pipes, it is difficult to achieve stable welding by hand when welding copper pipes to stainless steel pipes or stainless steel pipes to stainless steel pipes.

[0130] In other embodiments, as shown in Figures 9 and 10, the oil separator 100 includes a cylinder 10, an air inlet pipe 50, an air outlet pipe 30, and an oil return pipe 70.

[0131] Specifically, the cylinder 10 has an oil separation chamber 115 (as shown in Figure 12). The cylinder 10 is made of steel and has a first through hole 117, a second through hole 118, and a third through hole 119. The first end of the air inlet pipe 50 is inserted into the first through hole 117 and welded to the cylinder 10. The first end of the air outlet pipe 30 is inserted into the second through hole 118 and welded to the cylinder 10. The first end of the oil return pipe 70 is inserted into the third through hole 119 and welded to the cylinder 10.

[0132] The second end of the intake pipe 50 is welded with a first copper connecting pipe 16, which is connected to the oil separation chamber 115 through the intake pipe 50; the second end of the exhaust pipe 30 is welded with a second copper connecting pipe 17, which is connected to the oil separation chamber 115 through the exhaust pipe 30; and the second end of the return oil pipe 70 is welded with a third copper connecting pipe 18, which is connected to the oil separation chamber 115 through the return oil pipe 70. It should be noted that when the oil separator 100 is applied in the refrigerant circulation loop, the oil separator 100 is installed between the compressor 210 (as shown in Figure 19) and the four-way valve 220 (as shown in Figure 19). When the compressor 210 discharges, the lubricating oil in the compressor 210, along with the heat exchange medium, is discharged into the oil separation chamber 115 through the first copper connecting pipe 16 and the inlet pipe 50. The oil separator 100 separates the heat exchange medium and the lubricating oil. The heat exchange medium flows to the four-way valve 220 through the outlet pipe 30 and the second copper connecting pipe 17, while the lubricating oil returns to the gas-liquid separator 240 or the compressor 210 through the return oil pipe 70 and the third copper connecting pipe 18. The first copper connecting pipe 16, the second copper connecting pipe 17, and the third copper connecting pipe 18 can be made of deoxidized phosphor bronze, copper, or other copper alloys.

[0133] It is understandable that in this application, by welding the first copper connecting pipe 16, the second copper connecting pipe 17, and the third copper connecting pipe 18 to the second end of the intake pipe 50, the second end of the outlet pipe 30, and the second end of the oil return pipe 70 respectively, before connecting the oil separator 100 to the compressor 210 and other components via piping, a transition copper pipe can be welded to the connection end of the corresponding piping first, and then the first copper connecting pipe 16, the second copper connecting pipe 17, and the third copper connecting pipe 18 are welded to the corresponding transition copper pipes respectively. Welding between copper pipes is more convenient, and stable welding can be achieved through manual brazing or manual fusion welding. For brazing, flame welding or high-frequency welding technology can be selected; for fusion welding, argon arc welding technology can be selected. Furthermore, when the intake pipe 50, the outlet pipe 30, and the oil return pipe 70 are made of stainless steel or carbon steel, since the oil separator 100 is relatively small, the oil separator 100 can be integrated as a whole. Placed in a high-temperature furnace, the first copper connecting pipe 16, the second copper connecting pipe 17, and the third copper connecting pipe 18 are welded to the inlet pipe 50, the outlet pipe 30, and the return oil pipe 70 respectively using a furnace welding process. When welding steel pipes and copper pipes using the furnace welding process, in a high-temperature environment, the furnace contains hydrogen or hydrogen from the decomposition of ammonia. Hydrogen is a reducing gas, which can reduce the oxide film on the outside of the steel pipe, allowing the steel pipe and copper pipe to be brazed in the furnace. This ensures the welding stability of the first copper connecting pipe 16, the second copper connecting pipe 17, and the third copper connecting pipe 18 with the inlet pipe 50, the outlet pipe 30, and the return oil pipe 70. Similarly, furnace welding can also be used when welding transition copper pipes at the connection ends of corresponding pipes. The welding temperature parameters for furnace welding are 800 degrees to 1082 degrees (this temperature is the actual surface temperature of the product to be welded in the furnace). Of course, the welding temperature parameters for furnace welding can also be selected according to actual needs.

[0134] In some embodiments, the cylinder 10, inlet pipe 50, outlet pipe 30, and oil return pipe 70 are made of stainless steel or carbon steel. It is understood that stainless steel and carbon steel are less expensive than copper, effectively reducing the cost of the oil separator 100. Furthermore, stainless steel and carbon steel have good structural strength and are not easily deformed, improving connection stability and resistance to vibration stress. Stainless steel also has good corrosion resistance, effectively resisting the erosion of the heat exchange medium in environments with frequent heat exchange. When the cylinder 10, inlet pipe 50, outlet pipe 30, and oil return pipe 70 are made of stainless steel, the stainless steel can be formed from Fe, Cr, and Ni elements. The addition of Cr and Ni elements gives the stainless steel a lower pitting corrosion potential, lower pitting corrosion weight loss, and a lower martensitic transformation temperature, making it more difficult for the stainless steel to undergo martensitic phase transformation during processing. This results in stronger resistance to pitting corrosion and stress corrosion, allowing for direct flame welding without annealing.

[0135] In some embodiments, the intake pipe 50, the exhaust pipe 30, and the oil return pipe 70 are all welded steel pipes. Compared with seamless steel pipes, welded steel pipes are cheaper and easier to process and form.

[0136] In some embodiments, the inner diameter of the cylinder 10 is d, where 19 mm ≤ d ≤ 89 mm. It is understood that when d is less than 19 mm, the diameter of the cylinder 10 is too small, resulting in a smaller oil separation chamber 115 within the cylinder 10 and thus lower oil separation efficiency of the oil separator 100. When d is greater than 89 mm, the diameter of the cylinder 10 is too large, occupying a significant amount of space and potentially leading to an excessively large overall size. Furthermore, it can cause structural instability in the cylinder 10, making it prone to deformation due to impact. Here, d can be 19 mm, 25 mm, 30 mm, 40 mm, 45 mm, 70 mm, 89 mm, or other values.

[0137] As shown in Figure 11, in some embodiments, the first through hole 117 is located on the circumference of the cylinder 10, and the axial length of the first through hole 117 is H, where 1.2 mm ≤ H ≤ 7 mm. It can be understood that the first through hole 117 can be a flanged hole formed by stamping the side of the cylinder 10. H is the flanged length along its axial direction. When H is less than 1.2 mm, the flanged length is too small, the welding length between the air inlet pipe 50 and the flange is too short, and the air inlet pipe 50 is prone to loosening after welding. When H is greater than 7 mm, the flanged length is too large, which will increase the volume of the oil separator 100, making it difficult to transport and place the oil separator 100. H can be 1.2 mm, 2 mm, 3 mm, 4 mm, 5 mm, 7 mm, or other values.

[0138] In some embodiments, an arc transition surface is provided at the connection between the outer surface of the first through hole 117 and the cylinder 10. The arc transition surface can achieve a smooth transition connection between the flange and the cylinder 10, preventing breakage at the connection between the flange and the cylinder 10. The radius of the arc transition surface is R, where 0.2 mm ≤ R ≤ 1.2 mm. When R is less than 0.2 mm, the radius of the arc transition surface is too small, making it difficult to achieve a smooth transition connection between the flange and the cylinder 10. When R is greater than 1.2 mm, the radius of the arc transition surface is too large, which will affect the thickness of the flange, resulting in a reduction in the thickness of the flange, and thus affecting the structural strength of the flange. R can be 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, or other values.

[0139] In some embodiments, the axis O2 of the first through hole 117 is perpendicular to and does not intersect with the axis O1 of the cylinder 10, such that the axis O2 of the first through hole 117 is eccentrically set relative to the axis O1 of the cylinder 10. This allows the mixture formed by the lubricating oil and heat exchange medium of the compressor 210 to enter the oil separation chamber 115 along the first through hole 117. When the mixture enters the oil separator 100 along the first through hole 117, it has a tangential velocity, which allows the mixture to rotate inside the cylinder 10. This enables the mixture to achieve oil-gas separation through centrifugal force, preventing the mixture from directly colliding with the cylinder 10, reducing kinetic energy loss, and accelerating the oil-gas separation speed. Furthermore, there is a certain distance between the mixture and the axis O1 of the cylinder 10, which prolongs the oil-gas separation path and extends the rotation time of the mixture inside the cylinder 10, thereby improving the oil-gas separation effect.

[0140] In some embodiments, the cylinder 10 includes a main body section 11, a first transition section 111, and a second transition section 113. The first transition section 111 is located between the top end of the main body section 11 and the second through hole 118, and the second through hole 118 is connected to the first transition section 111. The second transition section 113 is located between the bottom end of the main body section 11 and the third through hole 119, and the third through hole 119 is connected to the second transition section 113. It should be noted that the second through hole 118 and the third through hole 119 can be formed by spin compression of the cylinder 10. Compared with the main body section 11, the aperture of the second through hole 118 and the third through hole 119 is smaller, which can accelerate the flow rate of fluid (such as lubricating oil, heat exchange medium, etc.) through the second through hole 118 and the third through hole 119, thereby improving the oil-gas separation efficiency of the oil separator 100. In addition, it also facilitates the welding of the thinner-diameter outlet pipe 30 and return oil pipe 70 to the cylinder 10.

[0141] The outer surfaces of the first transition segment 111 and the second transition segment 113 are both trumpet-shaped inclined surfaces. The angle between the outer surface of the first transition segment 111 and the axis of the first transition segment 111 is α1, where 30 degrees ≤ α1 ≤ 67.5 degrees. The angle between the outer surface of the second transition segment 113 and the axis of the second transition segment 113 is α2, where 30 degrees ≤ α2 ≤ 67.5 degrees. Understandably, the first transition section 111 is used to achieve the transition connection between the main body section 11 and the second through hole 118, and the second transition section 113 is used to achieve the transition connection between the main body section 11 and the third through hole 119. Taking α1 as an example, when α1 is less than 30 degrees, the slope of the outer surface of the first transition section 111 is too large, and stress concentration and cracks are likely to occur at the connection between the first transition section 111 and the main body section 11 and the second through hole 118. When α1 is greater than 67.5 degrees, the slope of the outer surface of the first transition section 111 is too small. With the length of the first transition section 111 being a fixed value, this will result in the diameter of the second through hole 118 being too large, failing to meet the design requirements. Here, α1 can be 30 degrees, 45 degrees, 60 degrees, 67.5 degrees, or other degrees, and α2 can be 30 degrees, 45 degrees, 60 degrees, 67.5 degrees, or other degrees.

[0142] As shown in Figures 12 to 14, the air inlet pipe 50 is inserted into the first through hole 117, the air outlet pipe 30 is inserted into the second through hole 118, and the oil return pipe 70 is inserted into the third through hole 119; this facilitates welding of the air inlet pipe 50, the air outlet pipe 30, and the oil return pipe 70 to the cylinder 10. Specifically, the air inlet pipe 50 can be inserted into the first through hole 117, or the first through hole 117 can be inserted into the air inlet pipe 50; the air outlet pipe 30 can be inserted into the second through hole 118, or the second through hole 118 can be inserted into the air inlet pipe 30; and the oil return pipe 70 can be inserted into the third through hole 119, or the third through hole 119 can be inserted into the oil return pipe 70.

[0143] The insertion lengths of the intake pipe 50 and the first through hole 117, the exhaust pipe 30 and the second through hole 118, and the return oil pipe 70 and the third through hole 119 are all L1, where 7 mm ≤ L1 ≤ 30 mm. This ensures that the intake pipe 50 and the first through hole 117, the exhaust pipe 30 and the second through hole 118, and the return oil pipe 70 and the third through hole 119 all have sufficient insertion lengths to guarantee weld penetration depth and thus ensure connection stability. L1 can be 7 mm, 15 mm, 20 mm, 25 mm, 30 mm, or other values.

[0144] It should also be noted that, according to experiments, when steel pipes are welded together using tin bronze solder, corrosion and leakage are likely to occur at the weld when the insertion length is less than 7 mm. In a neutral salt spray test, corrosion and leakage usually occur within 100 to 500 hours. However, when the insertion length is greater than 7 mm, the corrosion resistance of the weld can be effectively improved, and corrosion and leakage can occur after more than 1000 hours in a neutral salt spray test. When steel pipes are welded together using copper solder, even if the insertion length is less than 7 mm, corrosion and leakage can occur after more than 1000 hours in a neutral salt spray test. Therefore, when L1 is greater than or equal to 7 mm, tin bronze or copper solder can be used to weld the air inlet pipe 50 to the first through hole 117, the air outlet pipe 30 to the second through hole 118, and the oil return pipe 70 to the third through hole 119.

[0145] In some embodiments, the connecting surfaces of the intake pipe 50 and the first through hole 117, the exhaust pipe 30 and the second through hole 118, and the oil return pipe 70 and the third through hole 119 are all provided with textured structures. It is understood that, taking the welding of the intake pipe 50 and the first through hole 117 as an example, the textured structure can be provided on the outer peripheral surface of the portion of the intake pipe 50 inserted into the first through hole 117, or on the inner wall surface of the portion where the first through hole 117 and the intake pipe 50 are welded. When the solder melts between the inner wall of the intake pipe 50 and the first through hole 117, the textured structure can increase the roughness of the connecting surfaces of the intake pipe 50 and the first through hole 117, thereby providing capillary action for the solder, allowing the solder to flow along the textured structure, thus increasing the solder's spread length and improving the welding effect. The textured structure can be a brushed structure or a knurled structure, or other structures that can increase the surface roughness of the connecting surfaces of the intake pipe 50 and the first through hole 117.

[0146] As shown in Figures 12 and 13, in some embodiments, the vent pipe 30 includes a first branch pipe 31 and a second branch pipe 33. The first branch pipe 31 is a steel pipe and is located inside the oil separation chamber 115. The second branch pipe 33 is a copper pipe. The first end of the second branch pipe 33 is inserted into the oil separation chamber 115 and welded to the first branch pipe 31 and the cylinder 10. The second end of the second branch pipe 33 extends out of the oil separation chamber 115 from the first through hole 117. The second copper connecting pipe 17 is welded to the second end of the second branch pipe 33. It is understandable that the first branch pipe 31 is inserted into the oil separation chamber 115, and the first branch pipe 31 is a steel pipe. The first branch pipe 31 can be welded to the cylinder 10 by furnace welding to extend the length of the gas outlet pipe 30 into the oil separation chamber 115, so that the heat exchange medium can be better discharged from the oil separator 100 along the gas outlet pipe 30, and the cost of the gas outlet pipe 30 can be reduced. The second branch pipe 33 is a copper pipe, and the second branch pipe 33 can also be welded to the first branch pipe 31 by furnace welding. The second branch pipe 33 and the second copper connecting pipe 17 are both copper pipes, which makes the welding of the second branch pipe 33 and the second copper connecting pipe 17 more convenient. The first branch pipe 31 and the cylinder 10, the second branch pipe 33 and the first branch pipe 31, and the second copper connecting pipe 17 and the second branch pipe 33 can also be welded simultaneously in the same furnace welding process.

[0147] As shown in Figure 14, in some embodiments, a filter assembly 90 is provided inside the third through hole 119. The filter assembly 90 is made of stainless steel and is welded to the inner wall of the cylinder 10. The filter assembly 90 can filter impurities in the lubricating oil, preventing the lubricating oil from carrying too many impurities back to the compressor 210 and affecting the normal operation of the compressor 210. Furthermore, the stainless steel construction of the filter assembly 90 can reduce its cost and improve its corrosion resistance. Alternatively, the filter assembly 90 can be welded to the cylinder 10 using furnace welding.

[0148] As shown in Figures 15 to 17, in some embodiments of this application, the first copper connecting pipe 16 is connected to the air inlet pipe 50, the second copper connecting pipe 17 is connected to the air inlet pipe 50, and the third copper connecting pipe 18 is connected to the oil return pipe 70 by a plug-in connection, so as to facilitate welding of the first copper connecting pipe 16 to the air inlet pipe 50, the second copper connecting pipe 17 to the air inlet pipe 50, and the third copper connecting pipe 18 to the oil return pipe 70. Specifically, the first copper connecting pipe 16 can be inserted into the air inlet pipe 50, or the air inlet pipe 50 can be inserted into the first copper connecting pipe 16; the second copper connecting pipe 17 can be inserted into the air outlet pipe 30, or the air outlet pipe 30 can be inserted into the second copper connecting pipe 17; the third copper connecting pipe 18 can be inserted into the oil return pipe 70, or the oil return pipe 70 can be inserted into the third copper connecting pipe 18.

[0149] In one embodiment, the insertion lengths of the first copper connecting pipe 16 to the air inlet pipe 50, the second copper connecting pipe 17 to the air inlet pipe 50, and the third copper connecting pipe 18 to the oil return pipe 70 are all L2, where 7 mm ≤ L2 ≤ 30 mm. This ensures that the first copper connecting pipe 16 to the air inlet pipe 50, the second copper connecting pipe 17 to the air inlet pipe 50, and the third copper connecting pipe 18 to the oil return pipe 70 all have sufficient insertion lengths to guarantee weld penetration depth, thereby ensuring connection stability. L2 can be 7 mm, 15 mm, 20 mm, 25 mm, 30 mm, or other values.

[0150] Secondly, based on the oil separator 100 described above, this application also provides a method for preparing the oil separator 100, used to prepare the oil separator 100 in the above embodiments, as shown in FIG18, the preparation method includes:

[0151] S10. The two ends of the steel cylinder 10 are spun into a compression port to form a second through hole 118 and a third through hole 119. The spun into a compression port is a cold working process, which is simple and reliable and can reduce the manufacturing difficulty of the oil separator 100.

[0152] S20. The side of the cylinder 10 is stamped to form the first through hole 117. Stamping is also a cold working process. The processing method is simple and reliable, which can reduce the processing and manufacturing difficulty of the oil separator 100.

[0153] S30. Insert the first end of the air inlet pipe 50 into the first through hole 117 and weld it to the cylinder body 10. Insert the first end of the air outlet pipe 30 into the second through hole 118 and weld it to the cylinder body 10. Insert the first end of the oil return pipe 70 into the third through hole 119 and weld it to the cylinder body 10.

[0154] S40, the first copper connecting pipe 16 is connected to the second end of the air inlet pipe 50, the second copper connecting pipe 17 is connected to the second end of the air outlet pipe 30, and the third copper connecting pipe 18 is connected to the second end of the oil return pipe 70 by furnace welding.

[0155] Before step S10, the cylinder 10 can be inspected and cleaned to ensure that the cylinder 10 is intact and to remove dirt from the cylinder 10, so as to facilitate the subsequent processing of the cylinder 10.

[0156] In some embodiments, step S10 includes

[0157] S11. Perform spin compression machining on one end of the cylinder 10 to form one of the second through hole 118 and the third through hole 119;

[0158] S12. Clean the cylinder 10;

[0159] S11. Perform a spin compression process on the other end of the cylinder 10 to form another of the second through hole 118 and the third through hole 119, so as to form the second through hole 118 and the third through hole 119 respectively through two spin compression processes.

[0160] In some embodiments, the cylinder 10 is made of stainless steel, and step S30 includes:

[0161] S31. Insert the first end of the intake pipe 50 into the first through hole 117, and insert the first end of the exhaust pipe 30 into the second through hole 118. Insert the first end of the return oil pipe 70 into the third through hole 119.

[0162] S32. The inlet pipe 50, outlet pipe 30 and oil return pipe 70 are welded to the cylinder 10 in the furnace using copper solder. Copper solder can ensure the welding stability of the inlet pipe 50, outlet pipe 30 and oil return pipe 70 to the cylinder 10, and can effectively improve the corrosion resistance of the weld. In addition, stainless steel itself has good corrosion resistance, so there is no need to set a protective layer at the welding point of the inlet pipe 50, outlet pipe 30 and oil return pipe 70 to the cylinder 10, which can reduce the preparation steps of the oil separator 100.

[0163] In other embodiments, the cylinder 10 is made of carbon steel, and step S30 includes:

[0164] S33. Insert the first end of the intake pipe 50 into the first through hole 117, insert the first end of the exhaust pipe 30 into the second through hole 118, and insert the first end of the return oil pipe 70 into the third through hole 119.

[0165] S34. Use copper solder to weld the air inlet pipe 50, air outlet pipe 30 and oil return pipe 70 to the cylinder 10 in the furnace.

[0166] S35. An anti-corrosion layer is formed on the surface of the cylinder 10, at the weld between the inlet pipe 50 and the cylinder 10, at the weld between the outlet pipe 30 and the cylinder 10, and at the weld between the return oil pipe 70 and the cylinder 10. It is understandable that carbon steel has stronger structural strength and hardness than stainless steel, and is easier to process, which simplifies the manufacturing process of the oil separator 100. Simultaneously, the anti-corrosion layer enhances the corrosion resistance of the welds between the inlet pipe 50, the outlet pipe 30, and the return oil pipe 70 and the cylinder 10, thereby ensuring the corrosion resistance of these welds.

[0167] The anti-corrosion layer can be formed by spraying or by surface treatment processes, such as chromium diffusion, carbon-chromium co-diffusion, molybdenum diffusion, carbon-molybdenum co-diffusion, nitriding, or nitrogen-carbon co-diffusion.

[0168] In some embodiments, after step S20 and before step S30, the filter assembly 90 can be installed at the third through hole 119 and the filter assembly 90 can be welded to the cylinder 10.

[0169] In some embodiments, step S40 includes:

[0170] S41. The first copper connecting pipe 16 is welded to the air inlet pipe 50, the second copper connecting pipe 17 is welded to the air outlet pipe 30, and the third copper connecting pipe 18 is welded to the oil return pipe 70 using tin bronze solder.

[0171] S42. The first copper connecting pipe 16 is welded to the inlet pipe 50, the second copper connecting pipe 17 to the outlet pipe 30, and the third copper connecting pipe 18 to the return oil pipe 70 using copper solder for a second welding in the furnace. It is understandable that compared with copper solder, tin bronze solder has a lower melting point and cost. Manual welding can be used to perform the first welding of the first copper connecting pipe 16 to the inlet pipe 50, the second copper connecting pipe 17 to the outlet pipe 30, and the third copper connecting pipe 18 to achieve pre-fixation and prevent the first copper connecting pipe 16, the second copper connecting pipe 17, and the third copper connecting pipe 18 from falling off during the process of transporting the welded cylinder 10 to the furnace. At the same time, copper solder has better corrosion resistance, which can improve the connection stability.

[0172] It should also be noted that after step S40, the formed oil separator 100 can be cleaned, its airtightness checked, a protective layer sprayed on, and packaged.

[0173] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this application and simplifying the description, and 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. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0174] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An oil separator, characterized in that, include: The cylinder has an oil separation chamber and an installation channel communicating with the oil separation chamber; and The vent pipe includes a first branch pipe and a second branch pipe formed separately. The first branch pipe is connected to the cylinder body and is at least partially located inside the cylinder body. One end of the first branch pipe and one end of the second branch pipe are connected and communicate with each other in the installation channel. A portion of the second branch pipe is located outside the cylinder body. The first branch pipe and the second branch pipe are connected by welding, and the first branch pipe is connected to the cylinder by welding.

2. The oil separator as described in claim 1, characterized in that, The material of the first branch pipe is different from that of the second branch pipe.

3. The oil separator as described in claim 1, characterized in that, One end of the first branch pipe and one end of the second branch pipe are sleeved in the installation channel, and the parts of the first branch pipe and the second branch pipe that are sleeved together are connected by welding.

4. The oil separator as described in claim 3, characterized in that, The end of the first branch pipe is sleeved outside the end of the second branch pipe; and / or, The projection of the second branch pipe onto the inner wall of the installation channel and the projection of the first branch pipe onto the inner wall of the installation channel have an overlapping portion. The width of the overlapping portion in the axial direction of the installation channel is h, which satisfies the relationship 2mm≤h≤15mm.

5. The oil separator as described in claim 4, characterized in that, At least one of the outer wall of the first branch pipe and the inner wall of the mounting channel is provided with a protrusion to define a welding gap between the outer wall of the first branch pipe and the inner wall of the mounting channel.

6. The oil separator according to any one of claims 1 to 5, characterized in that, The side wall of the cylinder is provided with a first through hole that connects to the oil separation chamber. In the height direction of the oil separator, the end of the first branch pipe that is away from the second branch pipe is located below the first through hole. The height difference between the end of the first branch pipe away from the second branch pipe and the axis of the first through hole is H1, and the height difference between the end of the first branch pipe away from the second branch pipe and the bottom of the oil separation chamber is H2, satisfying the relationship 0.1≤H1 / H2≤0.

6.

7. The oil separator according to any one of claims 1 to 6, characterized in that, The side wall of the cylinder is provided with a first through hole that connects to the oil separation chamber, and the axis of the first through hole is spaced apart from the axis of the cylinder.

8. The oil separator as described in claim 7, characterized in that, The centerline of the first through hole is perpendicular to and does not intersect the centerline of the cylinder.

9. The oil separator as described in claim 7, characterized in that, It also includes an intake pipe, which passes through the first through hole, and the opening of one end of the intake pipe located in the oil separation chamber is inclined toward the first branch pipe; and / or, The inner diameter of the air intake pipe is d1, and the cylinder includes a main body section that defines the oil separation chamber. The inner diameter of the main body section is d2, satisfying the relationship 1.5≤d2 / d1≤4.

10. The oil separator according to any one of claims 1 to 9, characterized in that, The cylinder is also provided with an oil guide channel that connects to the oil separation chamber, and the oil guide channel is located at the bottom of the cylinder along the height direction of the oil separator; The oil separator also includes a filter assembly located within the oil guide channel.

11. The oil separator as claimed in claim 10, characterized in that, The filter assembly includes: The substrate is fixed within the oil guiding channel and defines the oil outlet; and A filter screen is connected to the substrate and covers the oil outlet. The filter screen is arched relative to the substrate into the oil separation chamber.

12. The oil separator as claimed in claim 11, characterized in that, It also includes an oil return pipe, one end of which is installed in the oil guide channel. The oil guide channel is provided with a first limiting surface, and the substrate is sandwiched between the end of the oil return pipe and the first limiting surface.

13. The oil separator as described in claim 12, characterized in that, The substrate includes a filter screen fixing part surrounding the oil inlet, the end face of the filter screen fixing part facing the first limiting surface being constructed as a second limiting surface, the second limiting surface abutting against the first limiting surface; or... Along the axial direction of the oil guide channel, the middle part of the substrate is provided with a second limiting surface facing the first limiting surface, and the second limiting surface abuts against the first limiting surface.

14. The oil separator as described in claim 12, characterized in that, The return oil pipe is welded to the inner wall of the oil guide channel.

15. The oil separator as described in claim 10, characterized in that, The cylindrical body includes: The main body section defines the oil separation chamber; A first reduced-diameter section connects to one end of the main body section and defines the mounting channel; the inner diameter of the first reduced-diameter section is smaller than the inner diameter of the main body section. The second reduced-diameter section connects to the end of the main body section away from the first reduced-diameter section and defines the oil guide channel. The inner diameter of the second reduced-diameter section is smaller than the inner diameter of the main body section.

16. The oil separator as described in claim 15, characterized in that, The main body segment includes a first transition segment, which connects to the first diameter-reducing segment, and the inner diameter of the first transition segment gradually decreases along the direction close to the first diameter-reducing segment; and / or, The main body segment includes a second transition segment, which connects to the second reduced diameter segment, and the inner diameter of the second transition segment gradually decreases along the direction close to the second reduced diameter segment.

17. The oil separator as described in claim 15, characterized in that, The cylindrical body is a single integral component; and / or, The outer diameter d3 of the main body section satisfies the condition 30mmn≤d3≤60mm.

18. The oil separator according to any one of claims 1 to 17, characterized in that, It also includes the intake manifold and the oil return manifold; The cylinder is made of steel and is provided with a first through hole, a second through hole and a third through hole; The first end of the air intake pipe is inserted into the first through hole and welded to the cylinder body, and the second end of the air intake pipe is welded with a first copper connecting pipe, which is connected to the oil separation chamber through the air intake pipe. The first end of the vent pipe is inserted into the second through hole and welded to the cylinder body. The second end of the vent pipe is welded with a second copper connecting pipe, which communicates with the oil separation chamber through the vent pipe. The first end of the return oil pipe is inserted into the third through hole and welded to the cylinder body. The second end of the return oil pipe is welded with a third copper connecting pipe, which is connected to the oil separation chamber through the return oil pipe.

19. The oil separator as claimed in claim 18, characterized in that, The cylinder, the air inlet pipe, and the oil return pipe are made of stainless steel or carbon steel.

20. The oil separator as claimed in claim 18, characterized in that, The air inlet pipe, the air outlet pipe, and the oil return pipe are all welded steel pipes.

21. The oil separator as claimed in claim 18, characterized in that, The inner diameter of the cylinder is d, where 19 mm ≤ d ≤ 89 mm.

22. The oil separator as described in claim 18, characterized in that, The first through hole is located on the periphery of the cylinder, and the length of the first through hole along its axial direction is H, 1.2 mm ≤ H ≤ 7 mm.

23. The oil separator as described in claim 22, characterized in that, An arc transition surface is provided at the connection between the outer side of the first through hole and the cylinder body. The radius of the arc transition surface is R, where 0.2 mm ≤ R ≤ 1.2 mm.

24. The oil separator as claimed in claim 18, characterized in that, The cylindrical body includes a main body section, a first transition section, and a second transition section. The first transition section is located between the top end of the main body section and the second through hole, and the second through hole is connected to the first transition section. The second transition section is located between the bottom end of the main body section and the third through hole, and the third through hole is connected to the second transition section. The outer surfaces of the first transition section and the second transition section are both trumpet-shaped inclined surfaces. The angle between the outer surface of the first transition section and the axis of the first transition section is α1, where 30 degrees ≤ α1 ≤ 67.5 degrees. The angle between the outer surface of the second transition section and the axis of the second transition section is α2, where 30 degrees ≤ α2 ≤ 67.5 degrees.

25. The oil separator as described in claim 18, characterized in that, The air intake pipe is inserted into the first through hole, the air outlet pipe is inserted into the second through hole, and the oil return pipe is inserted into the third through hole; The insertion length of the air intake pipe to the first through hole, the insertion length of the air outlet pipe to the second through hole, and the insertion length of the oil return pipe to the third through hole are L1, where 7 mm ≤ L1 ≤ 30 mm.

26. The oil separator as described in claim 18, characterized in that, The connection surfaces of the air intake pipe and the first through hole, the air outlet pipe and the second through hole, and the oil return pipe and the third through hole are all provided with textured structures.

27. A method for preparing an oil separator, characterized in that, include: The two ends of the steel cylinder are spun and compressed to form a second and a third through hole; The side of the cylinder is stamped to form the first through hole; The first end of the air inlet pipe is inserted into the first through hole and welded to the cylinder body; the first end of the air outlet pipe is inserted into the second through hole and welded to the cylinder body; and the first end of the oil return pipe is inserted into the third through hole and welded to the cylinder body. The first copper connecting pipe is welded to the second end of the air inlet pipe, the second copper connecting pipe is welded to the second end of the air outlet pipe, and the third copper connecting pipe is welded to the second end of the oil return pipe using a furnace welding process.

28. The method for preparing the oil separator as described in claim 27, characterized in that, The cylinder body is made of stainless steel. The steps of inserting the first end of the air inlet pipe into the first through hole and welding it to the cylinder body, inserting the first end of the air outlet pipe into the second through hole and welding it to the cylinder body, and inserting the first end of the oil return pipe into the third through hole and welding it to the cylinder body include: Insert the first end of the air inlet pipe into the first through hole, insert the first end of the air outlet pipe into the second through hole, and insert the first end of the oil return pipe into the third through hole. The air inlet pipe, the air outlet pipe, and the oil return pipe are welded to the cylinder in a furnace using copper solder.

29. The method for preparing the oil separator according to claim 27, characterized in that, The cylinder body is made of carbon steel. The steps of inserting the first end of the air inlet pipe into the first through hole and welding it to the cylinder body, inserting the first end of the air outlet pipe into the second through hole and welding it to the cylinder body, and inserting the first end of the oil return pipe into the third through hole and welding it to the cylinder body include: Insert the first end of the air inlet pipe into the first through hole, insert the first end of the air outlet pipe into the second through hole, and insert the first end of the oil return pipe into the third through hole. The air inlet pipe, the air outlet pipe, and the oil return pipe are welded to the cylinder in a furnace using copper solder. An anti-corrosion layer is formed on the surface of the cylinder, at the weld between the air inlet pipe and the cylinder, at the weld between the air outlet pipe and the cylinder, and at the weld between the oil return pipe and the cylinder.

30. The method for preparing the oil separator according to claim 27, characterized in that, The steps of welding the first copper connecting pipe to the second end of the intake pipe, welding the second copper connecting pipe to the second end of the exhaust pipe, and welding the third copper connecting pipe to the second end of the return oil pipe include: The first copper connecting pipe is first welded to the air inlet pipe, the second copper connecting pipe is first welded to the air outlet pipe, and the third copper connecting pipe is first welded to the oil return pipe using tin bronze solder. The first copper connecting pipe is welded to the inlet pipe, the second copper connecting pipe to the outlet pipe, and the third copper connecting pipe to the return oil pipe using copper solder in a furnace for a second welding.

31. A refrigerant circulation loop, characterized in that, The device includes a compressor, a four-way valve, a piping assembly, and an oil separator as described in any one of claims 1 to 26. The oil separator further includes an inlet pipe and an oil return pipe communicating with the oil separation chamber. The inlet pipe is connected to the exhaust port of the compressor through the piping assembly. The exhaust pipe is connected to the first through hole of the four-way valve through the piping assembly. The oil return pipe is connected to the first through hole of the compressor through the piping assembly.

32. A heating, ventilation, and air conditioning system, characterized in that, It includes an outdoor unit and an indoor unit, wherein the outdoor unit includes the refrigerant circulation loop as described in claim 31, and the outdoor unit is connected to the indoor unit through the piping assembly.

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