The present application relates to an evaporator, in particular to a shell-and-tube evaporator with high heat exchange efficiency.

A conventional refrigeration system has an evaporator, a condenser, a throttling device, and a compressor. When a low-temperature refrigerant liquid passes through the evaporator, it exchanges heat with the outside and absorbs heat from the outside, thereby lowering an outside temperature and achieving a refrigeration effect. The outside may be air or chilled water. After heat exchange, the refrigerant liquid vaporizes to become a refrigerant gas and enters the compressor. A shell-and-tube evaporator has certain requirements for a charge amount of refrigerant, and too much or too little may affect the heat exchange performance of the evaporator and even affect the operation of the entire refrigeration system.

An evaporator provided by the present application has high heat exchange efficiency, and compared with a conventional flooded evaporator, the evaporator provided by the present application can save a charge amount of refrigerant and improve the heat exchange efficiency of the evaporator.

The evaporator in the present application comprises: a housing, a first heat exchange tube group, a second heat exchange tube group, a first side blocking plate, and a second side blocking plate; the housing has an accommodating cavity and a refrigerant inlet and a refrigerant outlet which are in communication with the accommodating cavity, and the accommodating cavity has a length direction, a width direction, and a height direction; each heat exchange tube in the first heat exchange tube group and the second heat exchange tube group extends along the length direction of the accommodating cavity, the first heat exchange tube group is located at a lower part of the accommodating cavity, and the second heat exchange tube group is located above the first heat exchange tube group; and the first side blocking plate and the second side blocking plate are respectively arranged on two sides of the second heat exchange tube group in a width direction, and the first side blocking plate and the second side blocking plate are configured to guide a refrigerant flowing out from the first heat exchange tube group to flow toward the second heat exchange tube group, wherein each of the first side blocking plate and the second side blocking plate comprises a main body portion, the main body portion is arranged in close proximity to the second heat exchange tube group, the main body portion comprises a top and a bottom which are oppositely arranged and a waist portion located between the top and the bottom, and a distance between the waist portion of the first side blocking plate and the waist portion of the second side blocking plate is smaller than a distance between the top of the first side blocking plate and the top of the second side blocking plate, and is smaller than a distance between the bottom of the first side blocking plate and the bottom of the second side blocking plate.

According to the evaporator as described above, in a height direction, one end of each of the first side blocking plate and the second side blocking plate extends beyond the second heat exchange tube group, and the other end thereof extends to an inner wall of the housing.

According to the evaporator as described above, shapes of the main body portions match a shape of the second heat exchange tube group, the bottoms of the main body portions are arranged toward the first heat exchange tube group, the distance between the bottom of the main body portion of the first side blocking plate and the bottom of the main body portion of the second side blocking plate is W21, the distance between the tops is W22, and the distance between the waist portions is W23, wherein W21≥W22>W23.

According to the evaporator as described above, each of the main body portions comprises a first part and a second part, the first part extends from the top of the main body portion toward the waist portion, the second part extends from the bottom of the main body portion toward the waist portion, cross sections of the first part and the second part are straight lines, and an included angle between the first part and the second part is between 100° and 170°.

According to the evaporator as described above, cross sections of the main body portions of the first side blocking plate and the second side blocking plate are hyperbolas.

According to the evaporator as described above, each of the first side blocking plate and the second side blocking plate comprises an extension portion, and the extension portions are connected with the bottoms of the main body portions and extend to an inner wall of the housing along the width direction of the accommodating cavity.

According to the evaporator as described above, the evaporator further comprises a top blocking plate, the top blocking plate comprises an outlet section and a pair of flow guiding sections, the outlet section is arranged above the second heat exchange tube group and has distances from the first side blocking plate and the second side blocking plate, the pair of flow guiding sections are respectively connected with two ends of the outlet section, extend obliquely downward toward an inner wall of the housing, and have distances from the inner wall of the housing, and in the height direction of the accommodating cavity, respective distal ends of the pair of flow guiding sections are lower than the top of the main body portion of the first side blocking plate and the top of the main body portion of the second side blocking plate.

According to the evaporator as described above, in the width direction of the accommodating cavity, a maximum width of the first heat exchange tube group is greater than a maximum width of the second heat exchange tube group; the evaporator is configured such that a liquid level height of the refrigerant immerses the first heat exchange tube group; and liquid return openings are provided on the first side blocking plate and the second side blocking plate, and heights of the liquid return openings are higher than a height of the first heat exchange tube group.

According to the evaporator as described above, the evaporator further comprises a defogging blocking plate, and the defogging blocking plate is arranged between the top blocking plate and the housing to cover a gap between the top blocking plate and the housing; or the defogging blocking plate is arranged between the top blocking plate and the refrigerant outlet to cover the refrigerant outlet.

According to the evaporator as described above, the refrigerant inlet is adjacent to a lower part of the first heat exchange tube group, and a height of the refrigerant outlet is higher than a height of the second heat exchange tube group.

The evaporator in the present application has the first heat exchange tube group and the second heat exchange tube group, and the second heat exchange tube group is located above the first heat exchange tube group. The first side blocking plate and the second side blocking plate are arranged on two sides of the second heat exchange tube group, wherein the first side blocking plate and the second side blocking plate have waist portions, so that a fluid flowing through the second heat exchange tube group can be first accelerated and then decelerated, thereby improving the heat exchange efficiency of the evaporator.

• FIG. 1 is a schematic block diagram of a refrigeration system;
• FIG. 2 is a perspective view of a first embodiment of an evaporator in FIG. 1;
• FIG. 3A is one radial cross-sectional view of an evaporator in FIG. 2;
• FIG. 3B is a schematic diagram of one radial cross-sectional view of an evaporator in FIG. 3A with heat exchange tube groups hidden;
• FIG. 4A is one schematic diagram of an extension portion in FIG. 3A;
• FIG. 4B is another schematic diagram of an extension portion in FIG. 3A;
• FIG. 5 is a cross-sectional view of an evaporator of a second embodiment in the present application;
• FIG. 6 is a cross-sectional view of an evaporator of a third embodiment in the present application;
• FIG. 7 is a cross-sectional view of an evaporator of a fourth embodiment in the present application;
• FIG. 8 is a cross-sectional view of an evaporator of a fifth embodiment in the present application;
• FIG. 9 is a cross-sectional view of an evaporator of a sixth embodiment in the present application; and
• FIG. 10 is a cross-sectional view of an evaporator of a seventh embodiment in the present application.

Various specific embodiments of the present application will be described below with reference to the drawings, which constitute a part of the specification. It should be understood that although terms, such as "front", "rear", "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", "forward", "reverse", "proximal", "distal", "lateral", and "longitudinal", that represent directions are used in the present application to describe various example structural parts and elements of the present application, these terms are used herein for ease of illustration only and are determined based on example orientations shown in the drawings. Since the embodiments disclosed in the present application may be disposed in different directions, these terms that represent directions are for illustration only and should not be regarded as limiting.

Ordinal numbers, such as "first" and "second" used in the present application are only for distinction and identification, and do not have any other meaning. Unless otherwise specified, they do not indicate a specific order, nor do they have a specific relevance. For example, the term "first component" by itself does not imply the presence of "second component", nor does the term "second component" by itself imply the presence of "first component".

FIG. 1 is a schematic block diagram of a refrigeration system 100. As shown in FIG. 1, the refrigeration system 100 comprises a compressor 110, a condenser 120, a throttling device 140, and an evaporator 130, which are connected by pipes to form one refrigerant circulation loop, and the loop is filled with a refrigerant. As shown by an arrow direction in FIG. 1, the refrigerant flows through the compressor 110, the condenser 120, the throttling device 140, and the evaporator 130 in sequence, and enters the compressor 110 again. In a refrigeration process, the throttling device 140 throttles a high-pressure liquid refrigerant from the condenser 120 to reduce its temperature and pressure; the low-pressure refrigerant exchanges heat with an object to be cooled in the evaporator 130, absorbs heat from the object to be cooled, and is vaporized and evaporated; refrigerant vapor generated by vaporization is sucked into the compressor 110, compressed, and discharged at a high pressure; the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 110 exchanges heat with an ambient medium in the condenser 120, releases heat, and condenses into a liquid refrigerant; and the high-temperature liquid refrigerant flows through the throttling device 140 again to reduce a pressure. In this way in cycles, a continuous refrigeration effect is produced.

FIG. 2 is a perspective view of a first embodiment of the evaporator 130 in FIG. 1. As shown in FIG. 2, the evaporator 130 has a housing 201 and a pair of tube plates 208 and 209. The housing 201 is cylindrical with openings at two ends, and the pair of tube plates 208 and 209 are respectively placed at the two ends of the housing 201 to seal the openings at the two ends of the housing 201. The housing 201 and the pair of tube plates 208 and 209 enclose an accommodating cavity 305, and the accommodating cavity 305 is used to accommodate heat exchange tubes. Referring to the position shown in FIG. 2, the evaporator 130 has a height direction H, a length direction L, and a width direction W, and the height direction, length direction, and width direction of the accommodating cavity 305 are consistent with the directions of the evaporator 130. A refrigerant inlet 211 and a refrigerant outlet 212 are provided on the housing 201, wherein the refrigerant outlet 212 is located at an upper part of the evaporator 130 in the height direction, and the refrigerant inlet 211 is located at a lower part of the evaporator 130 in the height direction. The liquid refrigerant or gas-liquid mixed refrigerant in the refrigeration system 100 enters the evaporator 130 from the refrigerant inlet 211, absorbs heat in the evaporator 130 to become a gaseous refrigerant, and is discharged from the refrigerant outlet 212.

FIG. 3A is a radial cross-sectional view of the evaporator in FIG. 2. As shown in FIG. 3A, an accommodating cavity 305 is formed inside the housing 201, and a heat exchange tube group 310, a distributor 330, a first side blocking plate 311, a second side blocking plate 312, and a top blocking plate 370 are arranged in the accommodating cavity 305.

The heat exchange tube group 310 is a heat exchange tube bundle formed by a plurality of mutually parallel heat exchange tubes. Each heat exchange tube in the heat exchange tube bundle extends along the length direction L of the accommodating cavity 305. A fluid channel is formed in the heat exchange tubes for circulating water or other media. The fluid channel is formed by connecting a plurality of heat exchange tubes end to end in sequence. A gap between each heat exchange tube and an adjacent heat exchange tube forms a refrigerant channel for circulating the refrigerant. The medium in the fluid channel and the refrigerant in the refrigerant channel transfer heat through tube walls of the heat exchange tubes. The heat exchange tube group 310 comprises a first heat exchange tube group 301 and a second heat exchange tube group 302, wherein the second heat exchange tube group 302 is arranged above the first heat exchange tube group 301.

In one embodiment of the present application, as shown in combination with FIG. 2 and FIG. 3A, the refrigerant inlet 211 is arranged below the housing 201 and is located at a middle part of the evaporator 130 in the length direction. The refrigerant inlet 211 is also located at a middle part of the evaporator 130 in the width direction, such that in the height direction of the evaporator 130, the refrigerant inlet 211 is located at a lowest position. The distributor 330 is arranged at the bottom of the accommodating cavity 305, is located above the refrigerant inlet 211, and is used to guide the refrigerant entering the evaporator 130 to flow in the length direction of the accommodating cavity 305 so as to be distributed into the heat exchange tube group 310 as uniformly as possible.

In another embodiment of the present application, the positions of the refrigerant inlet 211 and the distributor 330 are higher than the bottom of the accommodating cavity 305, but not higher than the first heat exchange tube group 301.

As shown in FIG. 3A, the first heat exchange tube group 301 is arranged upward from an inner wall of the bottom of an accommodating cavity housing 201 and the outside of the distributor 330, and the first heat exchange tube group 301 has an upper part 315 and a lower part 316. The lower part 316 is arranged substantially in close proximity to and along the inner wall of the housing 201, and the upper part 315 is substantially flush in the height direction of the accommodating cavity 305. Viewed from the length direction L of the evaporator 130, a contour of the lower part 316 of the first heat exchange tube group 301 is substantially arc-shaped, a contour of the upper part 315 is substantially a horizontal straight line, and two ends of the lower part 316 are connected with two ends of the upper part 315. The upper part 315 has a first heat exchange tube group width W11.

The second heat exchange tube group 302 is arranged upward from the upper part 315 of the first heat exchange tube group 301, the second heat exchange tube group 302 has an upper part 318 and a lower part 319 as well as a pair of side parts 328 and 329, and the lower part 319 of the second heat exchange tube group 302 is in close proximity to the upper part 315 of the first heat exchange tube group 301. The lower part 319 of the second heat exchange tube group 302 has a second heat exchange tube group width W12, and the second heat exchange tube group width W12 is smaller than the first heat exchange tube group width W11. The second heat exchange tube group 302 is arranged in a middle part of the accommodating cavity 305 in the width direction, such that the pair of side parts 328 and 329 of the second heat exchange tube group 302 form certain distances from the inner wall of the housing 201 respectively.

The first heat exchange tube group 301 has a first region 361 and a pair of second regions 362 and 363, and the pair of second regions 362 and 363 are respectively located on two sides of the first region 361. In the width direction of the accommodating cavity 305, the bottom of the second heat exchange tube group 302 is aligned with the first region 361, and the second regions 362 and 363 are both offset from the lower part 319 of the second heat exchange tube group 302.

In one embodiment of the present application, the heat exchange tubes in the first heat exchange tube group 301 and the second heat exchange tube group 302 have the same tube diameter and are all uniformly arranged in columns, and the total number of columns of the first heat exchange tube group 301 is greater than the total number of columns of the second heat exchange tube group 302.

The second heat exchange tube group 302 has a middle part 317 between the upper part 318 and the lower part 319, and in the width direction of the accommodating cavity 305, the width of the second heat exchange tube group 302 gradually narrows from the lower part 319 toward the middle part 317, and then gradually widens from the middle part 317 toward the upper part 318. That is, at the middle part 317, the width of the second heat exchange tube group 302 is minimum. In one embodiment of the present application, the number of columns of a row of heat exchange tubes at the middle part 317 is minimum.

In the width direction, a first side blocking plate 311 and a second side blocking plate 312 are respectively arranged on two sides of the second heat exchange tube group 302, and the first side blocking plate 311 and the second side blocking plate 312 are used to guide a refrigerant flowing out from the first heat exchange tube group 301 to flow toward the second heat exchange tube group 302.

FIG. 3B is a schematic diagram of a radial cross-sectional view of the evaporator in FIG. 3A with heat exchange tubes hidden. In this embodiment, the first side blocking plate 311 and the second side blocking plate 312 are symmetrical structures. As shown in FIG. 3B, the first side blocking plate 311 comprises a main body portion 321 and an extension portion 323. The main body portion 321 is arranged in close proximity to the side part 328 of the second heat exchange tube group, and the extension portion 323 is located above the first heat exchange tube group 301. The main body portion 321 has a top 341, a bottom 342, and a waist portion 343. The waist portion 343 is located between the top 341 and the bottom 342. The top 341 extends beyond the upper part 318 of the second heat exchange tube group 302 in the height direction of the accommodating cavity 305. The bottom 342 is substantially flush with the lower part 319 of the second heat exchange tube group 302. The bottom 342 is connected with one side of the extension portion 323, and the extension portion 323 extends from the bottom 342 along the width direction of the accommodating cavity 305 toward the inner wall of the housing 201 and is connected with the inner wall of the housing 201. The main body portion 321 comprises a first part 351 and a second part 352, the first part 351 extends from the top 341 of the main body portion 321 toward the waist portion 343, and the second part 352 extends from the bottom 342 of the main body portion 321 toward the waist portion 343. In this embodiment, cross sections of the first part 351 and the second part 352 are straight lines, that is to say, both the first part 351 and the second part 352 are flat plates. Both the first part 351 and the second part 352 extend obliquely relative to the height direction of the accommodating cavity 305, and the waist portion 343 is closer to the main body portion 322 of the second side blocking plate 312 than the top 341 or the bottom 342, such that an obtuse included angle is formed between the first part 351 and the second part 352, and the included angle between the first part 351 and the second part 352 is between 100° and 170°.

Similarly, the second side blocking plate 312 comprises a main body portion 322 and an extension portion 324. The main body portion 322 is arranged in close proximity to the side part 329 of the second heat exchange tube group, and the extension portion 324 is located above the first heat exchange tube group 301. The main body portion 322 has a top 346, a bottom 347, and a waist portion 348. The waist portion 348 is located between the top 346 and the bottom 347. The top 346 extends beyond the upper part 318 of the second heat exchange tube group 302 in the height direction of the accommodating cavity 305. The bottom 347 is substantially flush with the lower part 319 of the second heat exchange tube group 302. The bottom 347 is connected with one side of the extension portion 324, and the extension portion 324 extends from the bottom 347 along the width direction of the accommodating cavity 305 toward the inner wall of the housing 201 and is connected with the inner wall of the housing 201. The main body portion 322 comprises a first part 356 and a second part 357, the first part 356 extends from the top 346 of the main body portion 322 toward the waist portion 348, and the second part 357 extends from the bottom 347 of the main body portion 322 toward the waist portion 348. In this embodiment, cross sections of the first part 356 and the second part 357 are straight lines, that is to say, both the first part 356 and the second part 357 are flat plates. Both the first part 356 and the second part 357 extend obliquely relative to the height direction of the accommodating cavity 305, and the waist portion 348 is closer to the main body portion 321 of the first side blocking plate 311 than the top 346 or the bottom 347, such that an obtuse included angle is formed between the first part 356 and the second part 357, and the included angle between the first part 356 and the second part 357 is between 100° and 170°.

In one embodiment of the present application, the extension portion 323 and the extension portion 324 are provided with liquid return openings 385 to allow a fluid to pass through. Areas of the liquid return openings 385 are small, so as to avoid more fluid that undergoes heat exchange through the first heat exchange tube group 301 from directly overflowing the liquid return openings 385.

In the width direction of the accommodating cavity 305, the respective main body portions 321 and 322 of the first side blocking plate 311 and the second side blocking plate 312 enclose a shape that is narrow in the middle and wide at two ends. A distance between the bottom 342 of the first side blocking plate 311 and the bottom 347 of the second side blocking plate 312 is W21, a distance between the top 341 of the first side blocking plate 311 and the top 346 of the second side blocking plate 312 is W22, a distance between the waist portion 343 of the first side blocking plate 311 and the waist portion 348 of the second side blocking plate 312 is W23, and a distance between distal ends of the respective extension portions 323 and 324 of the first side blocking plate 311 and the second side blocking plate 312 is W24, wherein W24>W21≥W22>W23.

The top blocking plate 370 is arranged above the heat exchange tube group 310, and extends along the width direction and the length direction of the accommodating cavity 305. The top blocking plate 370 comprises an outlet section 371 and a pair of flow guiding sections 372 and 373. The outlet section 371 is arranged above the second heat exchange tube group 302 and has certain distances from a top end of the first side blocking plate 311 and a top end of the second side blocking plate 312, capable of allowing the fluid to flow through between the top blocking plate 370 and the first side blocking plate 311 and the second side blocking plate 312. The pair of flow guiding sections 372 and 373 are respectively connected with two ends of the outlet section 371, and extend obliquely downward toward the inner wall of the housing 201. The flow guiding sections 372 and 373 have distances from the inner wall of the housing 201, and have distances from between the top end of the first side blocking plate 311 and the top end of the second side blocking plate 312. In the height direction of the accommodating cavity 305, the respective distal ends of the flow guiding sections 372 and 373 are lower than the tops of the respective main body portions 321 and 322 of the first side blocking plate 311 and the second side blocking plate 312.

In this embodiment, a width of the outlet section 371 is greater than W22. In other embodiments, the width of the outlet section 371 may be less than W22, as long as a maximum width between the flow guiding sections 372 and 373 can be greater than W22. The outlet section 371 and the flow guiding sections 372 and 373 may be respectively separate components connected together by welding or screw connection or the like, or may be an integrally formed component.

The distributor 330 is approximately in an elongated strip shape, and extends along the length direction of the accommodating cavity 305. The distributor 330 comprises a first plate 398 and a second plate 399, proximal ends of the first plate 398 and the second plate 399 in the width direction are connected with each other, and an included angle is formed between the first plate 398 and the second plate 399. Viewed from one cross section, the distributor 330 is in an inverted "V" shape. When the distributor 330 is installed in the accommodating cavity 305, distal ends of the first plate 398 and the second plate 399 abut against a lower part of the housing 201, and an elongated strip-shaped distribution space 339 is formed between the distributor 330 and the housing 201. The refrigerant inlet 211 is in communication with the distribution space 339. The distributor 330 is capable of guiding the refrigerant entering the distribution space 339 to flow along the length direction to be rapidly and uniformly distributed into the first heat exchange tube group 301.

A flow direction of the refrigerant is shown in FIG. 3B, a hollow arrow represents a gaseous refrigerant, and a solid arrow represents a liquid refrigerant. A low-temperature refrigerant enters the distribution space 339 formed between the distributor 330 and the housing 201 from the refrigerant inlet 211. The refrigerant flows along the length direction of the accommodating cavity 305 in the distribution space 339. During the working process of the evaporator, a liquid level height of the refrigerant is maintained to be approximately flush with the top of the first heat exchange tube group 301, that is to say, the first heat exchange tube group 301 is immersed in the liquid refrigerant. In heat exchange tube gaps of the heat exchange tubes, the refrigerant exchanges heat with the fluid in the heat exchange tubes, and a part of the refrigerant absorbs heat and becomes gaseous. The gaseous refrigerant moves upward. The gaseous refrigerant generated in the heat exchange process in the first heat exchange tube group 310 entrains a large amount of liquid refrigerant to move upward and enter the second heat exchange tube group 302 to continue heat exchange. The first side blocking plate 311 and the second side blocking plate 312 guide the refrigerant to flow upward. Since at the connection between the first heat exchange tube group 301 and the second heat exchange tube group 302, a width of the second heat exchange tube group 302 is less than a width of the first heat exchange tube group 301, that is to say, a flow cross-sectional area of the second heat exchange tube group 302 is less than a flow cross-sectional area of the first heat exchange tube group 301, and thus the refrigerant entering the second heat exchange tube group 302 from the first heat exchange tube group 301 can be accelerated, so that the liquid refrigerant entrained by the gaseous refrigerant can flow upward in the second heat exchange tube group 302 to reach a certain height. The gas-liquid mixed refrigerant entering the second heat exchange tube group 302 continues to exchange heat with the second heat exchange tube group 302, a part of the liquid refrigerant is converted into a gaseous state, and continues to drive the refrigerant fluid to flow upward.

The refrigerant after heat exchange in the second heat exchange tube group 302 flows toward the top blocking plate 370, wherein the gaseous refrigerant flows out from the gap between the top blocking plate 370 and the first side blocking plate 311 and the second side blocking plate 312, and then flows out from the refrigerant outlet 212 after passing through the gap between the top blocking plate 370 and the housing 201. A part of the liquid refrigerant after heat exchange in the second heat exchange tube group 302 is blocked by the top blocking plate 370, then changes a flow direction, and returns into the heat exchange tube group 310 to continue heat exchange. The other part flows out from the gap between the top blocking plate 370 and the first side blocking plate 311 and the second side blocking plate 312, and the flow guiding sections 372 and 373 of the top blocking plate 370 guide this part of fluid downward into the space between the first side blocking plate 311 and the second side blocking plate 312 and the housing. Thus, the refrigerant falls onto the extension portion 323 of the first side blocking plate 311 and the extension portion 324 of the second side blocking plate 312. The refrigerant enters the first heat exchange tube group 301 again from the liquid return openings 385 on the extension portions 323 and 324 to continue heat exchange.

When the fluid undergoes heat exchange in the second heat exchange tube group 302, a flow velocity of the fluid changes. Below the heights of the waist portion 343 and the waist portion 348, the second part 352 of the first side blocking plate 311 and the second part 357 of the second side blocking plate 312 are inclined toward each other, and the flow cross-sectional area of the refrigerant gradually decreases from bottom to top. Therefore, when the refrigerant flows from the heights of the bottom 342 and the bottom 347 to the heights of the waist portion 343 and the waist portion 348, the flow velocity gradually increases, thereby ensuring that the liquid in the refrigerant gas is not separated due to gravity and can be entrained to a higher position, so as to ensure that surfaces of the heat exchange tubes above the waist portions 343 and 348 can obtain sufficient refrigerant liquid, thereby ensuring heat exchange performance.

Above the heights of the waist portion 343 and the waist portion 348, the first part 351 of the first side blocking plate 311 and the first part 356 of the second side blocking plate 312 are inclined away from each other, and the flow cross-sectional area of the refrigerant gradually increases from bottom to top. When the refrigerant flows from the heights of the waist portion 343 and the waist portion 348 to the heights of the top 341 and the top 346, the flow cross-sectional area of the refrigerant gradually increases, the flow velocity of the refrigerant gradually decreases, and large liquid droplets entrained in the refrigerant gas are separated from the gas due to gravity and fall back into the heat exchange tube group. When the refrigerant flows out from the upper part 318 of the second heat exchange tube group 302, a small amount of refrigerant liquid is separated from the gas when colliding with the top blocking plate 370 and returns into the second heat exchange tube group 302, or flows toward the outer sides of the first side blocking plate 311 and the second side blocking plate 312 along the flow guiding sections 372 and 373 of the top blocking plate 370.

The waist portion 343 and the waist portion 348 are substantially flush with the center position of the second heat exchange tube group 302, which can ensure the heat exchange effect of the heat exchange tubes below the center position of the second heat exchange tube group 302, and can also ensure that a certain number of heat exchange tubes are arranged above the center position of the second heat exchange tube group 302, reducing the liquid content of the refrigerant flowing out of the second heat exchange tube group 302.

In the present application, in this embodiment, the arrangement of the first side blocking plate 311 and the second side blocking plate 312 makes the heat exchange efficiency of the refrigerant high, and the liquid level of the refrigerant only needs to be maintained flush with the height of the first heat exchange tube group 301, which can save a certain amount of refrigerant. Due to the arrangement of the waist portion 343 and the waist portion 348, the flow of the fluid performing heat exchange in the second heat exchange tube group 302 has two stages of acceleration and deceleration, the acceleration stage is conducive to the fluid flowing to a higher height, and the deceleration stage is conducive to the separation of gas and liquid in the fluid. The first side blocking plate 311 and the second side blocking plate 312 having the waist portion 343 and the waist portion 348 can improve the heat exchange efficiency of the fluid in the second heat exchange tube group 302.

FIG. 4A is a schematic diagram of the extension portion in FIG. 3A, and FIG. 4B is another schematic diagram of the extension portion in FIG. 3A.

As shown in FIG. 4A, the liquid return opening 385 is a hole 486 penetrating through the extension portion 323. As shown in FIG. 4B, the liquid return opening 385 is a notch 487 recessed inward from an edge of the extension portion 323.

FIG. 5 is a cross-sectional view of an evaporator of a second embodiment in the present application, which is similar to the embodiment shown in FIG. 3A, except that shapes of a first side blocking plate 511 and a second side blocking plate 512 are different. In the embodiment shown in FIG. 5, the first side blocking plate 511 comprises a main body portion 521 and an extension portion 523, the main body portion 521 comprises a first part 551 and a second part 552, wherein the extension portion 523 has the same extending direction as the second part 552, and no longer forms an included angle with the second part 552. A distal end of the extension portion 523 extends downward beyond an upper part 518 of a first heat exchange tube group 501. Similarly, the second side blocking plate 512 comprises a main body portion 522 and an extension portion 524, the main body portion 522 comprises a first part 556 and a second part 557, wherein the extension portion 524 has the same extending direction as the second part 557, and no longer forms an included angle with the second part 557. A distal end of the extension portion 524 extends downward beyond an upper part 518 of a first heat exchange tube group 501. In the working process of this embodiment, a liquid level height of a refrigerant is substantially flush with the upper part 515 of the first heat exchange tube group 501, therefore, a part of the extension portion 523 and the extension portion 524 can be immersed in the first heat exchange tube group 501.

The first side blocking plate 511 and the second side blocking plate 512 of the embodiment shown in FIG. 5 have waist portions 543 and 548, and can achieve technical effects similar to those of the embodiment shown in FIG. 3A.

FIG. 6 is a cross-sectional view of an evaporator of a third embodiment in the present application, which is similar to the embodiment shown in FIG. 5, except that the shapes of a top blocking plate 670, a first side blocking plate 611 and a second side blocking plate 612 are different. In the embodiment shown in FIG. 6, in a radial cross section, the shapes of the first side blocking plate 611 and the second side blocking plate 612 are curves, and the waist portions 643 and 648 are the closest parts of the two curves. That is to say, a main body portion 621 and an extension portion 623 of the first side blocking plate 611 smoothly transition therebetween, and a first part 651 and a second part 652 of the main body portion 621 smoothly transition therebetween. A main body portion 622 and an extension portion 624 of the second side blocking plate 612 smoothly transition therebetween, and a first part 656 and a second part 657 of the main body portion 622 smoothly transition therebetween.

Similarly, the cross section of the top blocking plate 670 is also arc-shaped, that is, an outlet section 671 and flow guiding sections 672 and 673 smoothly transition therebetween.

The first side blocking plate 611 and the second side blocking plate 612 of the embodiment shown in FIG. 6 have waist portions 643 and 648, and can achieve technical effects similar to those of the embodiment shown in FIG. 3A.

FIG. 7 is a cross-sectional view of an evaporator of a fourth embodiment in the present application, which is similar to the embodiment shown in FIG. 6, except that the embodiment in FIG. 7 further comprises defogging blocking plates 701 and 703. The defogging blocking plates 701 and 703 are respectively arranged between distal ends of two sides of the top blocking plate 770 and a housing 201 to connect the distal ends of the top blocking plate 770 with the housing 201. The defogging blocking plates 701 and 703 close the distance between the distal ends of the top blocking plate 770 and the housing 201, and a fluid flowing out from a second heat exchange tube group 702 needs to pass through the defogging blocking plates 701 and 703 to flow toward a refrigerant outlet 212. The defogging blocking plates 701 and 703 are porous flat plates capable of preventing a part of liquid droplets from passing through. The defogging blocking plates 701 and 703 extend obliquely upward from the distal ends of the top blocking plate 770 to facilitate guiding the liquid fluid back into the heat exchange tube group.

The first side blocking plate 711 and the second side blocking plate 712 of the embodiment shown in FIG. 7 have waist portions 743 and 748, and can achieve technical effects similar to those of the embodiment shown in FIG. 3A. The defogging blocking plates in FIG. 7 can further reduce the liquid content of the fluid flowing toward the refrigerant outlet 212.

FIG. 8 is a cross-sectional view of an evaporator of a fifth embodiment in the present application, which is similar to the embodiment shown in FIG. 7, except that connection positions of defogging blocking plates 801 and 802 and a top blocking plate 870 of the embodiment in FIG. 8 are different. The defogging blocking plates 801 and 802 are arranged to be connected with an end of an outlet section of the top blocking plate 870 and a housing 201. Further, the connection positions of the defogging blocking plates 801 and 802 with the top blocking plate 870 can be any positions of the top blocking plate 870, as long as a gap between the top blocking plate 870 and the housing 201 is closed.

The first side blocking plate 811 and the second side blocking plate 812 of the embodiment shown in FIG. 8 have waist portions 843 and 848, and can achieve technical effects similar to those of the embodiment shown in FIG. 3A. The defogging blocking plates in FIG. 8 can further reduce the liquid content of the fluid flowing toward the refrigerant outlet 212.

FIG. 9 is a cross-sectional view of an evaporator of a sixth embodiment in the present application, which is similar to the embodiment shown in FIG. 8, except that the position arrangement of a defogging blocking plate 901 of the embodiment in FIG. 9 is different. In a height direction of an accommodating cavity, the defogging blocking plate 901 is arranged above a top blocking plate 970, that is, located between a refrigerant outlet 212 and the top blocking plate 970. An edge of the defogging blocking plate 901 is connected with an inner wall of a housing 201, and a fluid entering the refrigerant outlet 212 needs to pass through the defogging blocking plate 901.

The first side blocking plate 911 and the second side blocking plate 912 of the embodiment shown in FIG. 9 have waist portions 943 and 948, and can achieve technical effects similar to those of the embodiment shown in FIG. 3A. The defogging blocking plates in FIG. 9 can further reduce the liquid content of the fluid flowing toward the refrigerant outlet 212.

FIG. 10 is a cross-sectional view of an evaporator of a seventh embodiment in the present application, which is similar to the embodiment shown in FIG. 6, except that the embodiment in FIG. 10 no longer provides a top blocking plate and a defogging blocking plate. Compared with the embodiment of FIG. 6, the embodiment of FIG. 10 has more rows of second heat exchange tube groups 1002. That is to say, the number of heat exchange tubes is greater. The heat exchange tubes at a top of the second heat exchange tube group 1002 can function as a top blocking plate and a defogging blocking plate to reduce the liquid content of the fluid.

The first side blocking plate 1011 and the second side blocking plate 1012 of the embodiment shown in FIG. 10 have waist portions 1043 and 1048, and can achieve technical effects similar to those of the embodiment shown in FIG. 3A.

Although the present disclosure has been described in conjunction with the examples of embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or foreseeable now or in the near future, may become apparent to those of at least ordinary skill in the art. In addition, the technical effects and/or technical problems described in the present specification are exemplary rather than restrictive; and therefore, the disclosure in the present specification may be used to solve other technical problems and have other technical effects. Accordingly, various changes may be made without departing from the spirit or scope of the present disclosure. Accordingly, the present disclosure is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.