Shell-and-tube heat exchanger and air conditioning unit

Abstract

The application provides a shell-and-tube heat exchanger and an air conditioning unit. The shell-and-tube heat exchanger comprises a shell, a flash structure and a liquid separation structure arranged in the shell, a refrigerant inlet is arranged on the shell, the liquid separation structure is arranged on the side of the flash structure away from the refrigerant inlet, and the refrigerant entering through the refrigerant inlet flows through the flash structure and the liquid separation structure in sequence. The shell-and-tube heat exchanger and the air conditioning unit have the advantages that the flash structure is arranged in the shell-and-tube heat exchanger, the integration degree of the product is improved, the use of connecting pipelines is reduced, the pipeline vibration is reduced, the safety hidden danger of refrigerant leakage is reduced, the refrigerant throttled by the flash structure is subjected to gas-liquid separation, the uniformity of liquid separation is improved, the problem that the refrigerant splashes due to the fact that the refrigerant does not impact the outside of the heat exchange pipe is reduced, the film distribution effect is enhanced, and the heat transfer coefficient is improved.

Description

Technical Field

[0001] This invention relates to the field of air handling equipment technology, and in particular to a shell-and-tube heat exchanger and an air conditioning unit. Background Technology

[0002] In addition to the four main components—compressor, condenser, throttling device, and evaporator—a refrigeration system also requires auxiliary components such as oil separators, flash evaporators, and gas-liquid separators to improve unit performance. These, along with piping and electrical control equipment, ensure reliable operation. Centrifugal chillers often employ a two-stage compression, two-stage throttling, and incomplete cooling refrigeration cycle. The high-temperature, high-pressure refrigerant from the condenser passes through a first-stage throttling orifice plate into the flash evaporator for gas-liquid separation. The gas is then supplied between the high- and low-pressure compressor stages, while the liquid passes through a second-stage throttling orifice plate into the evaporator.

[0003] In particular, compared to a single-stage compression refrigeration cycle, the two-stage compression, two-stage throttling, and incomplete cooling refrigeration cycle used in centrifugal chillers improves system capacity and energy efficiency while reducing compressor discharge temperature. However, it also increases the need for orifice plates, flash evaporators, and connecting pipe components. On the one hand, the added components increase the unit's manufacturing cost, and the flash evaporator adds a safety hazard to the pressure vessel. On the other hand, it also increases the risk of vibration in the connecting pipes and refrigerant leakage. Summary of the Invention

[0004] To address the technical problems of complex refrigeration system structures in existing technologies, such as vibration of connecting pipes and refrigerant leakage, a shell-and-tube heat exchanger and air conditioning unit that combines a flash evaporation structure with a heat exchange structure to reduce structural complexity is provided.

[0005] A shell-and-tube heat exchanger includes a shell and a flash structure and a liquid distribution structure disposed within the shell. The shell has a refrigerant inlet, and the liquid distribution structure is disposed on the side of the flash structure away from the refrigerant inlet. The refrigerant entering through the refrigerant inlet flows sequentially through the flash structure and the liquid distribution structure.

[0006] The flash structure includes at least two throttling plates. All the throttling plates are arranged side by side in the housing along the direction away from the refrigerant inlet. The uppermost throttling plate and the corresponding housing, as well as the two adjacent throttling plates and the corresponding housing, form a first gas-liquid separation space. The refrigerant entering through the refrigerant inlet flows through all the first gas-liquid separation spaces in sequence.

[0007] One end of the throttling plate is provided with a throttling orifice, and the throttling orifices of two adjacent throttling plates are staggered.

[0008] All of the aforementioned throttling plates include at least a second throttling plate located at the bottom layer, the second throttling plate having an inclined portion forming an angle with the horizontal plane, and the throttling orifice being disposed on the inclined portion.

[0009] Along the width direction of the second throttling plate, the second throttling plate includes a planar portion and an inclined portion arranged side by side. The planar portion has a spacing between itself and the adjacent throttling plate to allow refrigerant to flow, and the spacing between the inclined portion and the adjacent throttling plate gradually increases in the direction away from the planar portion.

[0010] The housing is provided with an air inlet, which is connected to the spacing.

[0011] The flash structure also includes a filter plate disposed on the inclined portion. The filter plate is provided with filter holes, and the filter plate, part of the inclined portion and the corresponding shell together form a liquid accumulation space. The filter plate, part of the inclined portion, the adjacent throttling plate and the corresponding shell together form a first gas-liquid separation space.

[0012] The flash structure also includes multiple baffles, all of which are staggered within the first gas-liquid separation space.

[0013] The liquid separation structure includes a flow plate, and all the throttling plates include a second throttling plate located at the bottom. The flow plate is disposed below the second throttling plate, and the flow plate, the second throttling plate and the corresponding shell form a second gas-liquid separation space.

[0014] The flow plate is provided with flow holes, which are offset from the flow holes on the second throttling plate.

[0015] The shell-and-tube heat exchanger includes a side baffle located below the second throttling plate and on one side of the flow plate. On the first side of the side baffle, the flow plate, the second throttling plate, and part of the side baffle together form the second gas-liquid separation space. On the second side of the side baffle, the side baffle and the corresponding shell form an exhaust area.

[0016] An air outlet is provided on the side baffle, and the second gas-liquid separation space is connected to the exhaust area through the air outlet.

[0017] A filter mechanism is provided at the air outlet.

[0018] The flow plate is provided with flow holes, and the air outlet is located above the flow holes.

[0019] The housing is provided with an exhaust port, and an air baffle is provided between the exhaust port and the air outlet.

[0020] The shell-and-tube heat exchanger also includes multiple heat exchange tubes, all of which are located below the liquid distribution structure and on the first side of the side baffle.

[0021] The liquid separation structure further includes at least two liquid separation plates, all of which are arranged side by side below the flow plate, and liquid separation spaces are formed between the uppermost liquid separation plate and the flow plate, and between two adjacent liquid separation plates.

[0022] The liquid distribution plate is provided with liquid distribution holes, and the liquid distribution holes of two adjacent liquid distribution plates are staggered.

[0023] The flash structure includes at least two throttling plates, and the liquid distribution structure also includes at least two liquid distribution plates. A side sealing plate is connected between the edges of the uppermost throttling plate and the lowermost liquid distribution plate on the same side. The side sealing plate is configured to conform to the corresponding part of the housing.

[0024] An air conditioning unit includes the aforementioned shell-and-tube heat exchanger.

[0025] The shell-and-tube heat exchanger and air conditioning unit provided by this invention integrate the flash structure within the shell-and-tube heat exchanger, improving product integration, reducing the use of connecting pipes and thus reducing safety hazards such as pipe vibration and refrigerant leakage. At the same time, the refrigerant after throttling by the flash structure undergoes gas-liquid separation, enabling the liquid separation structure to separate the liquid refrigerant after gas-liquid separation, improving the uniformity of liquid separation, reducing refrigerant impact on the outside of the heat exchange tubes to avoid refrigerant splashing, enhancing the film effect, and improving the heat transfer coefficient. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the flash structure and liquid separation structure provided in the embodiments of the present invention;

[0027] Figure 2 This is another structural schematic diagram of an embodiment provided by the present invention;

[0028] Figure 3 This is a cross-sectional view of a shell-and-tube heat exchanger provided in an embodiment of the present invention;

[0029] Figure 4 Another cross-sectional view of the shell-and-tube heat exchanger provided in the embodiment of the present invention;

[0030] Figure 5 Another cross-sectional view of the shell-and-tube heat exchanger provided in the embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the structure of the throttle plate provided in the embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the structure of the second throttle plate in an embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram of the structure of the filter plate provided in an embodiment of the present invention;

[0034] Figure 9 This is a schematic diagram of the flow plate structure provided in an embodiment of the present invention;

[0035] Figure 10 This is a schematic diagram of the side baffle and flow plate provided in the embodiment of the present invention;

[0036] Figure 11 This is a schematic diagram of the side sealing plate, throttling plate, and liquid separating plate provided in the embodiments of the present invention;

[0037] In the picture:

[0038] 1. Shell; 2. Flash structure; 3. Liquid separation structure; 101. Refrigerant inlet; 21. Throttling plate; 22. First gas-liquid separation space; 211. Throttling orifice; 212. Second throttling plate; 213. Inclined part; 214. Flat part; 102. Gas inlet; 23. Filter plate; 231. Filter hole; 24. Liquid accumulation space; 25. Baffle plate; 31. Flow plate; 26. Second gas-liquid separation space; 311. Flow hole; 4. Side baffle; 103. Exhaust area; 41. Gas outlet; 42. Baffle plate; 5. Filtration mechanism; 104. Exhaust port; 6. Heat exchange tube; 32. Liquid separation plate; 33. Liquid separation space; 321. Liquid separation orifice; 7. Side sealing plate. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0040] like Figures 1 to 11The shell-and-tube heat exchanger shown includes a shell 1 and a flash structure 2 and a liquid distribution structure 3 disposed within the shell 1. A refrigerant inlet 101 is provided on the shell 1. The liquid distribution structure 3 is located on the side of the flash structure 2 away from the refrigerant inlet 101, and the refrigerant entering through the refrigerant inlet 101 flows sequentially through the flash structure 2 and the liquid distribution structure 3. After the refrigerant entering through the refrigerant inlet 101 passes through the throttling of the flash structure 2 and the liquid distribution of the liquid distribution structure 3, it contacts the heat exchange tubes disposed within the shell 1, completing the flashing, liquid distribution, and heat exchange of the refrigerant. Integrating the flash structure 2 within the shell-and-tube heat exchanger improves product integration, reduces the use of connecting pipes, and lowers the safety hazards of pipe vibration and refrigerant leakage. Simultaneously, the refrigerant after throttling by the flash structure 2 undergoes gas-liquid separation, improving the uniformity of liquid distribution and reducing refrigerant splashing caused by refrigerant impacting the outside of the heat exchange tubes, enhancing the film distribution effect, and improving the heat transfer coefficient.

[0041] The flash structure 2 includes at least two throttling plates 21. All the throttling plates 21 are arranged side by side in the shell 1 in a direction away from the refrigerant inlet 101. The uppermost throttling plate 21 and its corresponding shell 1, as well as the two adjacent throttling plates 21 and their corresponding shell 1, each form a first gas-liquid separation space 22. The refrigerant entering through the refrigerant inlet 101 flows through all the first gas-liquid separation spaces 22 in sequence. By setting multiple throttling plates 21, the refrigerant is throttled multiple times inside the shell 1. The refrigerant in the first gas-liquid separation space 22 can effectively increase the throttling and flashing effect of the shell-and-tube heat exchanger on the refrigerant.

[0042] One end of the throttling plate 21 is provided with a throttling orifice 211, and the throttling orifices 211 on two adjacent throttling plates 21 are staggered. For example, in two adjacent throttling plates 21, the throttling orifice 211 is provided at the first end of one throttling plate 21, and the throttling orifice 211 is provided at the second end of the other throttling plate 21. That is, the flow path of the refrigerant between the throttling plates 21 is S-shaped, which maximizes the throttling flow path of the refrigerant within a certain space, thereby increasing the throttling effect of the refrigerant.

[0043] All of the aforementioned throttling plates 21 include at least a second throttling plate 212 located at the bottom layer. The second throttling plate 212 has an inclined portion 213 forming an angle with the horizontal plane, and the throttling orifice 211 is disposed on the inclined portion 213. The inclined portion 213 further achieves the effect of gas-liquid separation. The liquid refrigerant flows along the inclined portion 213 under the action of gravity, while the gaseous refrigerant remains above the liquid refrigerant, thereby achieving the effect of gas-liquid separation. At the same time, placing the throttling orifice 211 at the inclined portion 213 allows the liquid refrigerant to flow downward through the throttling orifice 211 as much as possible, further enhancing the effect of gas-liquid separation.

[0044] Along the width direction of the second throttling plate 212, the second throttling plate 212 includes a flat portion 214 and an inclined portion 213 arranged side by side. The flat portion 214 has a spacing between itself and the adjacent throttling plate 21 for refrigerant to flow through. Along the direction away from the flat portion 214, the spacing between the inclined portion 213 and the adjacent throttling plate 21 gradually increases.

[0045] The housing 1 is provided with a gas inlet 102, which is connected to the gap. The gaseous refrigerant that has undergone at least one gas-liquid separation by the throttling plate 21 still contains liquid refrigerant, but the amount of liquid refrigerant is relatively small, which is sufficient to meet the requirements for gas replenishment to the compressor. Therefore, the gas inlet 102 can be set at the gap to utilize the gaseous refrigerant within the gap to replenish the compressor.

[0046] The flash structure 2 also includes a filter plate 23, which is disposed on the inclined portion 213. The filter plate 23 has filter holes 231. The filter plate 23, part of the inclined portion 213, and the corresponding shell 1 together form a liquid accumulation space 24. The filter plate 23, part of the inclined portion 213, the adjacent throttling plate 21, and the corresponding shell 1 together form a first gas-liquid separation space 22. The filter plate 23 is used to further separate the refrigerant above the second throttling plate 212. Larger droplets, after contacting the filter plate 23, are drawn into the liquid accumulation space 24 through the filter holes 231 under the action of airflow, forming a liquid refrigerant with a certain liquid level in the liquid accumulation space 24. The filter plate 23 can reduce the disturbance of the gaseous refrigerant to the liquid surface, thereby forming a liquid seal at the throttling orifice 211 of the second throttling plate 212, ensuring the stable operation of the throttling orifice 211.

[0047] The flash structure 2 also includes multiple baffles 25, all of which are staggered within the first gas-liquid separation space 22. By utilizing multiple baffles 25, the flow distance of the refrigerant within the first gas-liquid separation space 22 is maximized. Simultaneously, when the refrigerant impacts the baffles 25, small refrigerant droplets coalesce into larger droplets, thereby achieving gas-liquid separation.

[0048] All the baffles 25 are arranged in a staggered, vertical configuration. This fully utilizes the refrigerant's own gravity for liquid separation, increasing the separation effect. Preferably, the upper and lower baffles are arranged at intervals.

[0049] The liquid separation structure 3 includes a flow plate 31, and all the throttling plates 21 include a second throttling plate 212 located at the bottom. The flow plate 31 is disposed below the second throttling plate 212, and the flow plate 31, the second throttling plate 212, and the corresponding shell 1 form a second gas-liquid separation space 26. When the gas-liquid two-phase refrigerant enters the second gas-liquid separation space 26, small droplets collide with the flow plate 31 and condense into larger droplets, achieving gas-liquid collision separation. Simultaneously, the droplets naturally settle to the bottom of the second gas-liquid separation space 26 under gravity, achieving gas-liquid gravity separation.

[0050] The flow plate 31 is provided with a flow hole 311, which is offset from the throttling hole 211 on the second throttling plate 212 to maximize the flow distance of the refrigerant. Preferably, the second end of the second throttling plate 212 is provided with a throttling hole 211, while the flow hole 311 is located opposite to the first end of the second throttling plate 212.

[0051] Specifically, there are multiple flow holes 311.

[0052] The shell-and-tube heat exchanger includes a side baffle 4, which is located below the second throttling plate 212 and on one side of the flow plate 31. On the first side of the side baffle 4, the flow plate 31, the second throttling plate 212, and part of the side baffle 4 together form the second gas-liquid separation space 26. On the second side of the side baffle 4, the side baffle 4 and the corresponding shell 1 form an exhaust region 103. The side baffle 4 can block and collect the liquid droplets splashed during the falling film evaporation process, and at the same time facilitate the direct delivery of gaseous refrigerant in the second gas-liquid separation space 26 to the exhaust region 103, preventing gaseous refrigerant from entering the liquid separation structure 3 and the heat exchange tube area, thereby improving the liquid separation effect of the liquid separation structure 3 and the heat exchange effect of the heat exchange tube.

[0053] The side baffle 4 is provided with an air outlet 41, and the second gas-liquid separation space 26 is connected to the exhaust area 103 through the air outlet 41.

[0054] A filter mechanism 5 is provided at the air outlet 41. The filter mechanism 5 filters the airflow entering the exhaust area 103 through the air outlet 41, so that the droplets carried in the airflow come into contact with the filter mechanism 5 and form large droplets under the adsorption of the filter mechanism 5, which then fall into the second gas-liquid separation space 26, thereby achieving the purpose of gas-liquid filter separation and ultimately ensuring the reliability of the gaseous refrigerant in the exhaust area 103.

[0055] The flow plate 31 is provided with flow holes 311, and the air outlet 41 is located above the flow holes 311. This allows large droplets formed by the filtration mechanism 5 to directly enter the liquid separation structure 3 for separation after falling into the second gas-liquid separation space 26, thus preventing the large droplets from being carried away by the airflow again and affecting the filtration effect of the filtration mechanism 5.

[0056] Preferably, the filtration mechanism 5 includes a gas-liquid filter screen.

[0057] The housing 1 is provided with an exhaust port 104, and an air baffle 42 is provided between the air outlet 41 and the exhaust port 104. This increases the gas travel distance from the air outlet 41 to the exhaust port 104, forming a "U"-shaped air passage and reducing the risk of liquid being carried in by the compressor during air intake.

[0058] The shell-and-tube heat exchanger also includes multiple heat exchange tubes 6, all of which are located below the liquid separation structure 3 and on the first side of the side baffle 4. The side baffle 4 is fully utilized to form a U-shaped air passage (second gas-liquid separation space 26—liquid separation structure 3—heat exchange structure—exhaust area 103), increasing the travel distance of the gaseous refrigerant formed after the liquid refrigerant absorbs heat and reducing the risk of liquid carryover during compressor suction.

[0059] The liquid distribution structure 3 further includes at least two liquid distribution plates 32. All the liquid distribution plates 32 are arranged side by side below the flow plate 31, and liquid distribution spaces 33 are formed between the uppermost liquid distribution plate 32 and the flow plate 31, and between two adjacent liquid distribution plates 32. By setting multiple liquid distribution plates 32, the liquid distribution effect of the liquid distribution structure 3 is further enhanced. The liquid refrigerant passes through multiple liquid distribution spaces 33 in sequence, thereby achieving a uniform liquid distribution effect. In particular, the liquid refrigerant forms a stable liquid seal above the liquid distribution hole, and the refrigerant state is the same at different positions with no airflow blowing around the liquid level. Therefore, the liquid refrigerant is separated through the liquid distribution hole only under the action of gravity. At the same time, it also avoids the excessively high flow velocity of the gas-liquid two-phase refrigerant after mixing and separation, which would spray onto the outer wall of the heat exchange tube 6 and affect the film distribution effect.

[0060] The liquid distribution plate 32 is provided with liquid distribution holes 321, and the liquid distribution holes 321 on two adjacent liquid distribution plates 32 are staggered to increase the liquid distribution effect.

[0061] Specifically, in two adjacent liquid distribution plates 32, the axis of the liquid distribution hole 321 on the upper liquid distribution plate 32 is not collinear with the axis of the liquid distribution hole 321 on the lower liquid distribution plate 32, and there may be a gap in the x direction and / or y direction in the horizontal direction.

[0062] The flash evaporation structure 2 includes at least two throttling plates 21, and the liquid distribution structure 3 includes at least two liquid distribution plates 32. A side sealing plate 7 is connected between the edges of the uppermost throttling plate 21 and the lowermost liquid distribution plate 32 on the same side. The side sealing plate 7 is configured to conform to the corresponding part of the housing 1. The side sealing plate 7 makes the flash evaporation structure 2 and the liquid distribution structure 3 form a whole. At the same time, the side sealing plate 7 can further increase the sealing effect of the flash evaporation structure 2 and the liquid distribution structure 3, avoiding the need for both the flash evaporation structure 2 and the liquid distribution structure 3 to be directly sealed to the inner surface of the housing 1, which would increase the processing difficulty.

[0063] In particular, the shell-and-tube heat exchanger also includes a side sealing plate, which is arranged parallel to the baffle 25. The side sealing plate seals the first end of all the throttling plates 21 and the first end of all the liquid distribution plates 32, thereby increasing the sealing effect of the flash structure 2 and the liquid distribution structure 3. This avoids the need for both the flash structure 2 and the liquid distribution structure 3 to be directly sealed to the inner surface of the shell 1, which would increase the processing difficulty.

[0064] Example

[0065] Taking the flash structure 2, which includes two throttling plates 21, and the liquid separation structure 3, which includes two liquid separation plates 32, as an example:

[0066] Along the direction away from the refrigerant inlet 101, the two throttling plates 21 are the first-stage throttling plate and the second-stage throttling plate (second throttling plate 212), and the two liquid distribution plates 32 are the first-stage liquid distribution plate and the second-stage liquid distribution plate.

[0067] A liquid inlet pipe is installed at the refrigerant inlet 101, a gas inlet pipe is installed at the gas inlet 102, and a gas outlet pipe is installed at the exhaust outlet 104.

[0068] The high-temperature, high-pressure liquid refrigerant discharged from the condenser enters the evaporator through the liquid inlet pipe at the top of the shell 1. The refrigerant flows downward and passes through the primary throttling orifice on the primary throttling plate, achieving throttling and pressure reduction to become a gas-liquid two-phase system. The primary throttling orifice is located at one end of the heat exchanger's axial direction. The gas-liquid two-phase refrigerant enters the first gas-liquid separation space 22, which consists of a primary throttling plate at the top, a secondary throttling plate at the bottom, axial side sealing edges, circumferential side sealing plates 7, and the inner wall of the shell 1. A staggered baffle plate 25 is arranged along the axial direction of the heat exchanger within the first gas-liquid separation space 22. The gas-liquid two-phase refrigerant passes through the upper and lower baffle plates, achieving gas-liquid separation through collision. The secondary throttling plate is bent downwards at one end of the circumference and has a secondary throttling orifice at the lower axial end. A horizontally placed filter plate 23 is positioned at the midpoint of its inclined surface, with filter holes 231 machined on the filter plate 23. Therefore, the bottom of the filter plate 23, together with the secondary throttling plate, the side sealing plate 7, and the side sealing plate, forms a liquid accumulation space 24. The liquid accumulation space 24 is located at the bottom of the first gas-liquid separation space 22, where the liquid refrigerant gathers under the influence of gravity and airflow. Within the first gas-liquid separation space 22, the gas and liquid refrigerant flow axially along the shell 1. As it passes the upper and lower baffles, the two phases collide with them and their flow direction changes. Small droplets condense into larger droplets, which drip downwards along the baffles 25 and side sealing plate 7. Simultaneously, the larger droplets gradually settle at the bottom of the space under gravity as they flow axially. Finally, the larger droplets contact the top of the filter plate 23 and, under the influence of airflow, converge into the liquid accumulation space 24 through the filter holes 231. Within the liquid accumulation space 24, the liquid refrigerant reaches a certain level. The filter plate 23 reduces the disturbance of the liquid surface by the gaseous refrigerant, thereby forming a liquid seal at the secondary throttling orifice, ensuring the stable operation of the throttling orifice 211. The primary and secondary throttling orifices are located at both ends of the heat exchanger's axial direction, making full use of the heat exchanger's axial length to increase the refrigerant flow path and enhance the gas-liquid separation effect. At the same end as the secondary throttling orifice in the axial direction and at the other end in the circumferential direction, a gas supply pipe is installed on the shell 1 to guide the gaseous refrigerant separated after passing through the first gas-liquid separation space 22 into the compressor for gas supply.

[0069] After secondary throttling, the two-phase refrigerant enters the second gas-liquid separation space 26. The second gas-liquid separation space 26 consists of a top secondary throttling plate, a bottom flow plate 31, a circumferential outlet plate, and an axial side sealing plate. An outlet hole is machined at a higher position on the side sealing plate, away from the secondary throttling orifice. A gas-liquid filter screen (filter mechanism 5) is installed around the outlet hole within the second gas-liquid separation space 26, and a flow hole 311 is machined at the end of the flow plate 31 away from the secondary throttling orifice. As the two-phase refrigerant enters the second gas-liquid separation space 26, small droplets collide with the flow plate 31 and condense into larger droplets, achieving gas-liquid collision separation. Simultaneously, the droplets naturally settle to the bottom of the second gas-liquid separation space 26 under gravity, achieving gas-liquid gravity separation. When the airflow carrying a small amount of fine droplets reaches the outlet at a higher position, it comes into contact with the gas-liquid filter screen. Under the adsorption of the gas-liquid filter screen, the small droplets form larger droplets and fall to the bottom of the second gas-liquid separation space 26, thus achieving gas-liquid separation. Finally, the droplets pass through the flow hole 311 under the blowing action of the axial airflow, while the refrigerant gas enters the heat exchange space of the heat exchanger through the outlet.

[0070] Liquid refrigerant enters the primary liquid distribution space 33 through the flow orifice 311, with a primary liquid distribution plate at the bottom. The primary liquid distribution plate has evenly distributed distribution holes 321 machined along the axial and circumferential directions of the heat exchanger. Liquid refrigerant then enters the secondary liquid distribution space through these holes 321, with a secondary liquid distribution plate at the bottom. This secondary liquid distribution plate also has evenly distributed distribution holes 321 machined along the axial and circumferential directions of the heat exchanger. Within the primary and secondary liquid distribution spaces, the liquid refrigerant forms a stable liquid seal above the distribution holes 321. The refrigerant state is the same at different locations, and there is no airflow blowing around the liquid level. Therefore, the liquid is separated through the distribution holes 321 only under the influence of gravity. This also prevents the gas-liquid two-phase refrigerant from mixing and being sprayed onto the outer wall of the heat exchange tube 6 at excessively high flow rates, which would affect the film distribution effect. The distribution holes 321 on both liquid distribution plates 32 are staggered along the axial and circumferential directions to enhance the liquid separation effect.

[0071] An air conditioning unit includes the aforementioned shell-and-tube heat exchanger.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A shell and tube heat exchanger, characterized by: The application relates to a shell (1) and a flash structure (2) and a liquid separation structure (3) arranged in the shell (1), the shell (1) is provided with a refrigerant inlet (101), the liquid separation structure (3) is arranged on the side of the flash structure (2) away from the refrigerant inlet (101), and the refrigerant entering the refrigerant inlet (101) sequentially flows through the flash structure (2) and the liquid separation structure (3); the flash structure (2) comprises at least two throttle plates (21), all the throttle plates (21) are arranged in parallel in the shell (1) in the direction away from the refrigerant inlet (101), and the first gas-liquid separation space (22) is surrounded between the uppermost throttle plate (21) and the corresponding shell (1) and between the adjacent two throttle plates (21) and the corresponding shell (1), and the refrigerant entering the refrigerant inlet (101) sequentially flows through all the first gas-liquid separation spaces (22); one end of the throttle plate (21) is provided with a throttling hole (211), and the throttling holes (211) on the adjacent two throttle plates (21) are arranged alternately; at least a second throttle plate (212) located at the lowermost among all the throttle plates (21) is arranged, an inclined part (213) with an included angle with a horizontal plane is formed on the second throttle plate (212), and the throttling hole (211) is arranged on the inclined part (213); the flash structure (2) further comprises a liquid filter plate (23), the liquid filter plate (23) is arranged on the inclined part (213), the liquid filter plate (23) is provided with a liquid filter hole (231), the liquid filter plate (23), part of the inclined part (213) and the corresponding shell (1) jointly form a liquid accumulation space (24), and the liquid filter plate (23), part of the inclined part (213), the adjacent throttle plate (21) and the corresponding shell (1) jointly form the first gas-liquid separation space (22); the liquid separation structure (3) comprises an overflow plate (31), all the throttle plates (21) comprise the second throttle plate (212) located at the lowermost, the overflow plate (31) is arranged below the second throttle plate (212), and the overflow plate (31), the second throttle plate (212) and the corresponding shell (1) jointly form a second gas-liquid separation space (26).

2. The shell-and-tube heat exchanger of claim 1, wherein: Along the width direction of the second throttle plate (212), the second throttle plate (212) comprises a flat part (214) and an inclined part (213) arranged in parallel, the flat part (214) and the adjacent throttle plate (21) have a spacing for refrigerant circulation, and the spacing between the inclined part (213) and the adjacent throttle plate (21) gradually increases in the direction away from the flat part (214).

3. The shell and tube heat exchanger of claim 2, wherein: The shell (1) is provided with a gas supplementing port (102), and the gas supplementing port (102) is communicated with the spacing.

4. The shell and tube heat exchanger of claim 1, wherein: The flash structure (2) further comprises a plurality of baffles (25), all of which are staggered in the first gas-liquid separation space (22).

5. The shell and tube heat exchanger of claim 1, wherein: The flow plate (31) is provided with a flow hole (311), and the flow hole (311) is arranged in a staggered manner with the throttling hole (211) on the second throttling plate (212).

6. The shell and tube heat exchanger of claim 1, wherein: The shell-and-tube heat exchanger comprises a side baffle (4) located below the second throttling plate (212) and on one side of the flow plate (31), and on a first side of the side baffle (4), the flow plate (31), the second throttling plate (212) and part of the side baffle (4) jointly form the second gas-liquid separation space (26), and on a second side of the side baffle (4), the side baffle (4) and the corresponding shell (1) form an exhaust area (103).

7. The shell and tube heat exchanger of claim 6, wherein: The side baffle (4) is provided with an air outlet (41), and the second gas-liquid separation space (26) and the exhaust area (103) are communicated through the air outlet (41).

8. The shell and tube heat exchanger of claim 7, wherein: The air outlet (41) is provided with a filtering mechanism (5).

9. The shell and tube heat exchanger of claim 7, wherein: The flow plate (31) is provided with a flow hole (311), and the air outlet (41) is located above the flow hole (311).

10. The shell and tube heat exchanger of claim 7, wherein: The shell (1) is provided with an exhaust port (104), and the air outlet (41) and the exhaust port (104) are provided with a baffle plate.

11. The shell and tube heat exchanger of claim 6, wherein: The shell-and-tube heat exchanger further comprises a plurality of heat exchange pipes (6), all of which are arranged below the distribution structure (3), and all of which are located on the first side of the side baffle (4).

12. The shell and tube heat exchanger of claim 1, wherein: The distribution structure (3) further comprises at least two distribution plates (32), all of which are arranged side by side below the flow plate (31), and the uppermost distribution plate (32) and the flow plate (31) and the adjacent two distribution plates (32) form a distribution space (33).

13. The shell and tube heat exchanger of claim 12, wherein: The distribution plate (32) is provided with a distribution hole (321), and the distribution holes (321) on the adjacent two distribution plates (32) are arranged in a staggered manner.

14. The shell and tube heat exchanger of claim 1, wherein: The flash structure (2) comprises at least two throttling plates (21), and the distribution structure (3) further comprises at least two distribution plates (32), the uppermost throttling plate (21) and the lowermost distribution plate (32) are connected between the edges on the same side by a side sealing plate (7), and the side sealing plate (7) is arranged in a shape corresponding to the corresponding part of the shell (1).

15. An air conditioning unit characterized by: The shell-and-tube heat exchanger comprises a shell-and-tube heat exchanger according to any one of claims 1 to 14. The shell-and-tube heat exchanger comprises a shell-and-tube heat exchanger according to any one of claims 1 to 14.

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