(19)
(11) EP 4 524 501 A1

(12) EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43) Date of publication:
19.03.2025 Bulletin 2025/12

(21) Application number: 23802974.8

(22) Date of filing: 11.05.2023
(51) International Patent Classification (IPC): 
F28D 9/04(2006.01)
(52) Cooperative Patent Classification (CPC):
F28F 3/10; F28D 9/04
(86) International application number:
PCT/CN2023/093372
(87) International publication number:
WO 2023/217205 (16.11.2023 Gazette 2023/46)
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA
Designated Validation States:
KH MA MD TN

(30) Priority: 11.05.2022 CN 202210511442

(71) Applicant: ZHEJIANG SANHUA AUTOMOTIVE COMPONENTS CO., LTD.
Hangzhou, Zhejiang 310018 (CN)

(72) Inventor:
  • LI, Hua
    Hangzhou, Zhejiang 310018 (CN)

(74) Representative: Maikowski & Ninnemann Patentanwälte Partnerschaft mbB 
Postfach 15 09 20
10671 Berlin
10671 Berlin (DE)

   


(54) HEAT EXCHANGER


(57) A heat exchanger, comprising a first plate, a first connecting part, a second plate, a second connecting part, and a third plate; the second plate is located between the first plate and the third plate; the heat exchanger comprises a first side part and a second side part; the first connecting part is located on the first side part of the heat exchanger; the second connecting part is located on the second side part of the heat exchanger; the first connecting part, the first plate, and the second plate are of an integrated structure; the second connecting part, the second plate, and the third plate are of an integrated structure; a first circulation channel is formed between the first plate and the second plate; the first plate and the second plate are arranged in a sealed mode; the area where the first plate and the second plate are arranged in a sealed mode at least surrounds the first circulation channel; a second circulation channel is formed between the second plate and the third plate; the second plate and the third plate are arranged in a sealed mode; the area where the second plate and the third plate are arranged in a sealed mode at least surrounds the second circulation channel; the heat exchanger can be formed by folding a same plate, and the plates do not need to be stacked one by one, so that assembly is convenient.




Description


[0001] The present application claims the priority to Chinese Patent Application No. 202210511442.7, titled "HEAT EXCHANGER", filed with the China National Intellectual Property Administration on May 11, 2022, which is incorporated herein by reference in its entirety.

FIELD



[0002] The present application relates to the technical field of heat exchanging, and in particular to a heat exchanger.

BACKGROUND



[0003] A heat exchanger typically includes multiple heat-exchanging plates stacked in layers. Each of the heat-exchanging plates is provided with a flange on the periphery thereof, and the flanges of the adjacent heat-exchanging plates are sealedly arranged. The multiple heat-exchanging plates, which are arranged separately, need to be stacked one by one during assembly. Due to a large number of heat-exchanging plates, an assembly mistake may occur.

SUMMARY



[0004] An object of the present application is to provide a heat exchanger that is easy for assembling.

[0005] A heat exchanger is provided according to an embodiment of the present application, including a heat-exchanging plate, and the heat-exchanging plate includes: a first plate, a second plate, and a third plate, and the second plate is located between the first plate and the third plate, a first direction is defined, the heat exchanger includes a first side portion and a second side portion in the first direction, the heat exchanger further includes a first connecting portion and a second connection portion, and the first connecting portion is located on the first side portion and the second connection portion is located on the second side portion, and the first connecting portion, the first plate, and the second plate are formed into an integrated structure, and the second connection portion, the second plate and the third plate are formed into an integrated structure.

[0006] A first flow passage is formed between the first plate and the second plate, the first plate and the second plate are arranged in a sealed manner, and an area sealed by the first plate and the second plate at least encloses the first flow passage, and a second flow passage is formed between the second plate and the third plate, the second plate and the third plate are arranged in a sealed manner, and an area sealed by the second plate and the third plate at least encloses the second flow passage.

[0007] In the embodiments above, the first connecting portion, the first plate, the second plate, the second connecting portion and the third plate are formed into an integrated structure. The first connecting portion is located on the first side portion of the heat exchanger, and the second connecting portion is located on the second side portion of the heat exchanger, and at least a part of the heat exchanger can be formed by folding one single plate, which is beneficial for assembling.

BRIEF DESCRIPTION OF THE DRAWINGS



[0008] 

FIG. 1 is a schematic perspective view of a heat exchanger according to an embodiment of the present application;

FIG. 2 is a schematic structural view of the heat exchanger in FIG. 1 in one direction;

FIG. 3 is a schematic cross-sectional structural view along a line A-A in FIG. 1;

FIG. 4 is a schematic partially enlarged view at C in FIG. 3;

FIG. 5 is a schematic partially enlarged view at D in FIG. 3;

FIG. 6 is a schematic cross-sectional structural view along a line B-B in FIG. 1;

FIG. 7 is a schematic partially enlarged view at E in FIG. 6;

FIG. 8 is a schematic structural view of a heat-exchanging plate before assembling the heat exchanger according to the present application;

FIG. 9 is a schematic perspective view of a first plate of the heat exchanger according to the present application in one direction;

FIG. 10 is a schematic perspective view of the first plate of the heat exchanger according to the present application in another direction;

FIG. 11 is a schematic perspective view of a second plate of the heat exchanger according to the present application in one direction;

FIG. 12 is a schematic perspective view of the second plate of the heat exchanger according to the present application in another direction; and

FIG. 13 is a schematic cross-sectional structural view of a heat exchanger according to another embodiment of the present application.


DETAILED DESCRIPTION OF THE EMBODIMENTS



[0009] The embodiments will be described with reference to the accompany drawings. In order to fully understand the present application, specific details are mentioned in the following description. However, those skilled in the art should understand that the specific components, devices, and features illustrated in the drawings and described herein are merely exemplary, which should not be regarded as a limit.

[0010] As shown in FIG. 1 to FIG. 13, a heat exchanger 1 includes a heat-exchanging plate 2, which includes a first plate 10, a second plate 20, and a third plate 30. The second plate 20 is located between the first plate 10 and the third plate 30. A first direction is defined, and the heat exchanger 1 has a first side portion 110 and a second side portion 120 in the first direction. As shown in FIG. 1 to FIG. 3, a direction F is indicated as the first direction, and the first plate 10 and the second plate 20 are connected by a first connecting portion 50 on the first side portion 110 of the heat exchanger 1. The first connecting portion 50, the first plate 10, and the second plate 20 are formed into an integrated structure. The second plate 20 and the third plate 30 are connected by a second connecting portion 60 on the second side portion 120 of the heat exchanger 1. The second connecting part 60, the second plate 20, and the third plate 30 are formed into an integrated structure. As shown in FIG. 1 to FIG. 8, the first plate 10, the second plate 20, and the third plate 30 are formed by folding one single plate, a first flow passage 3 is formed between the first plate 10 and the second plate 20, and the first plate 10 and the second plate 20 are arranged in a sealed manner. An area sealed by the first plate 10 and the second plate 20 at least encloses the first flow passage 3 to seal the periphery of the first flow passage 3. A second flow passage 4 is formed between the second plate 20 and the third plate 30, and the second plate 20 and the third plate 30 are arranged in a sealed manner. An area sealed by the second plate 20 and the third plate 30 at least encloses the second flow passage 4 to seal the periphery of the second flow passage 4. The heat exchanger 1 can be formed by folding one single plate without stacking multiple plates one by one, which not only avoids a mis-assembly but also facilitates the assembly. By connecting the first plate 10 and the second plate 20 on the first side portion 110 of the heat exchanger 1 through the first connection portion 50 and connecting the second plate 20 and the third plate 30 on the second side portion 120 of the heat exchanger 1 through the second connection portion 60, the heat-exchanging plate 2 can be formed by continuously stamping or rolling one single plate rather than stamping multiple heat-exchanging plates 2 separately, which improves the processing efficiency and reducing the processing cost.

[0011] As shown in FIG. 1 to FIG. 8, one single plate is folded to form the heat-exchanging plate 2. The heat-exchanging plates 2 in odd-numbered layers have the same structure, and the heat-exchanging plates 2 in even-numbered layers have the same structure, that is, the first plate 10 and the third plate 30 have the same structure. Alternatively, the heat exchanger 1 may also have only three heat-exchanging plates 2, that is, the first plate 10, the second plate 20, and the third plate 30, and the first plate 10 and the third plate 30 may also have different structures.

[0012] As shown in FIG. 1 to FIG. 13, the second plate 20 includes a first base portion 21 and a first convex portion 22 protruding relative to the first base portion 21. The first convex portion 22 is annular and is arranged around the second flow passage 4. The first convex portion 22 and the third plate 30 are arranged in a sealed manner, and the first convex portion 22 ensures that the second flow passage 4 has a certain height. The height of the second flow passage 4 can be adjusted by adjusting the height of the first convex portion 22. The first plate 10 and the first base portion 21 located on the periphery of the first convex portion 22 are arranged in a sealed manner. A length of the first connecting portion 50 is less than that of the second connecting portion 60. By shortening the length of the first connecting portion 50, it can not only reduce the cost but also reduce the weight of the heat exchanger 1. Certainly, an annular convex portion, which protrudes towards the first plate 10, may also be provided on the first base portion 21 located inside the first convex portion 22 for cooperating with the first plate 10 in a sealed manner, so as to seal the periphery of the first flow passage 3; or an annular convex portion, which protrudes towards the second plate 20 located inside the first convex portion 22, is provided on the first plate 10 for cooperating with the first base portion 21 in a sealed manner, so as to seal the periphery of the first flow passage 3; or an annular convex portion protruding towards the first plate 10 is provided on the first base portion 21 located inside the first convex portion 22 while an annular convex portion protruding towards the second plate 20 is provided on the first plate 10, and these two annular convex portions are sealedly arranged so as to seal the periphery of the first flow passage 3. The expressions "being sealedly arranged" and "in a sealed manner" herein may refer to being fixed by brazing or fixed by sealant, etc..

[0013] In some embodiments, the first flow passage 3 and the second flow passage 4 are provided with convex portions for turbulence. As shown in FIG. 1 to FIG. 12, the heat exchanger 1 further includes a fourth plate 40, and the third plate 30 is located between the second plate 20 and the fourth plate 40. A third connecting portion 70 is located on the first side portion 110 of the heat exchanger. The third plate 30 and the fourth plate 40 are connected by the third connecting portion 70, and the third connecting portion 70, the third plate 30, and the fourth plate 40 are formed into an integrated structure. A third flow passage 5 is provided between the third plate 30 and the fourth plate 40, and the third plate 30 and the fourth plate 40 are arranged in a sealed manner. An area sealed by the third plate 30 and the fourth plate 40 at least encloses the third flow passage 5 to seal the periphery of the third flow passage 5. The first plate 10 includes a second base portion 11 and a second convex portion 12 protruding relative to the second base portion 11. The second base portion 11 is arranged around the second convex portion 12. The second plate 20 includes a first base portion 21 and a first convex portion 22 protruding relative to the first base portion 21. A protruding direction of the second convex portion 12 is opposite to that of the first convex portion 22. The first convex portion 22 is annular. The first base portion 21 includes a first inner base portion 211 and a first outer base portion 212. The first convex portion 22 is arranged around the first inner base portion 211, and the first outer base portion 212 is arranged around the first convex portion 22. The third plate 30 includes a third base portion 31 and a third convex portion 32 protruding relative to the third base portion 31. A protruding direction of the third convex portion 32 is opposite to that of the first convex portion 22, and the third base portion 31 is arranged around the third convex portion 32. The fourth plate 40 includes a fourth base portion 41 and a fourth convex portion 42 protruding relative to the fourth base portion 41. A protruding direction of the fourth convex portion 42 is opposite to that of the third convex portion 32. The fourth convex portion 42 is annular, and the fourth base portion 41 includes a fourth inner base portion 411 and a fourth outer base portion 412. The fourth convex portion 42 is arranged around the fourth inner base portion 411, and the fourth outer base portion 412 is arranged around the fourth convex portion 42. The second base portion 11 and the first outer base portion 212 are arranged in a sealed manner, the first convex portion 22 and the third convex portion 32 are arranged in a sealed manner, and the third base portion 31 and the fourth outer base portion 412 are arranged in a sealed manner. The second convex portion 12 is provided with a first convex portion 13 protruding towards the second plate 20, and at least a part of the first convex portion 13 abuts against the first inner base portion 211. The first inner base portion 211 is provided with a second convex portion 23 protruding towards the third plate 30, and at least a part of the second convex portion 23 abuts against the third convex portion 32. The third convex portion 32 is provided a third convex portion 33 protruding towards the fourth plate 40, at least a part of the third convex portion 33 abuts against the fourth inner base portion 411. The fourth base portion 41 is provided with a fourth convex portion 43 protruding away from the third plate 30. In this embodiment, the convex portion is of a long-strip shape, and the long-strip convex portion is arranged at an angle relative to the length direction of the heat-exchanging plate 2. Certainly, the convex portion may also be a shape of herringbone wave or a spot wave, for example, the convex portion is multiple discrete circular convex portions or polygonal convex portions. It should be noted that, in case that the heat exchanger 1 is only provided with the first plate 10, the second plate 20, and the third plate 30, that is, in case that the heat exchanger 1 is only provided with the first flow passage 3 and the second flow passage 4, only the first convex portion 13 and the second convex portion 23 may be provided, or only the second convex portion 23 and the third convex portion 33 are provided, or only the second convex portion 23 is provided. Certainly, a convex portion protruding toward the first plate 10 and a convex portion protruding toward the third plate 30 may be provided on the second plate 20.

[0014] As shown in FIG. 13, the first flow passage 3 or the second flow passage 4 may not be provided with convex portions for turbulence, that is, the second convex portion 12 of the first plate 10 is not provided with the convex portion, the first inner base portion 211 of the second plate 20 located inside the first convex portion 22 is not provided with the convex portion, and the third convex portion 32 of the third plate 30 is not provided with the convex portion. The first flow passage 3 and the second flow passage 4 may enhance the turbulence effect to the heat transfer fluid by providing fins, thereby improving the heat exchanging effect. Certainly, the turbulence effect may be achieved by providing plates having convex portions only in one of the first flow passage 3 and the second flow passage 4 while providing fins in the other one.

[0015] In some embodiments, the heat exchanger 1 further includes a first corner duct 6, a second corner duct 7, a third corner duct 8, and a fourth corner duct 9. The first flow passage 3 is in communication with the first corner duct 6 and the second corner duct 7, the second flow passage 4 is in communication with the third corner duct 8 and the fourth corner duct 9, and the third flow passage 5 is in communication with the first corner duct 6 and the second corner duct 7. In case that the heat exchanger 1 has multiple flow passages, the flow passages in odd-numbered layers are in communication with the first corner duct 6 and the second corner duct 7, and the flow passages in even-numbered layers are in communication with the third corner duct 8 and the fourth corner duct 9. As shown in FIG. 1 to FIG. 12, each heat-exchanging plate 2 has a first corner hole 100, a second corner hole 200, a third corner hole 300, and a fourth corner hole 400, and the first corner holes 100 of the multiple heat-exchanging plates 2 are at least partially aligned to form the first corner duct 6, the second corner holes 200 of the multiple heat-exchanging plates 2 are at least partially aligned to form the second corner duct 7, the third corner holes 300 of the multiple heat-exchanging plates 2 are at least partially aligned to form the third corner duct 8, and the fourth corner holes 400 of the multiple heat-exchanging plates 2 are at least partially aligned to form the fourth corner duct 9. The first corner hole 100 and the second corner hole 200 are circular and located at both ends of the heat-exchanging plate 2 in the length direction, and the first corner hole 100 and the second corner hole 200 are arranged close to the second side portion 120 of the heat exchanger 1. The third corner hole 300 and the fourth corner hole 400 are elliptical and located at both ends of the heat exchanger 1 in the length direction, and the third corner hole 300 and the fourth corner hole 400 are arranged close to the first side portion 110 of the heat exchanger 1. Specifically, the first plate 10 is provided with two first bosses 14 protruding towards the second plate 20, and a top of each first boss 14 is arranged in the same plane as the second base portion 11. The top of the first boss 14 is provided with either the third corner hole 300 or the fourth corner hole 400. The first corner hole 100 and the second corner hole 200 of the first plate 10 are located at the second convex portion 12, and the second plate 20 is provided with two second bosses 24 protruding towards the third plate 30. A top of each second boss 24 is located on the same plane as the top of the first convex portion 22, and the top of the second convex portion 24 is provided with either the first corner hole 100 or the second corner hole 200. The third corner hole 300 and the fourth corner hole 400 of the second plate 20 are located at the first inner base portion 211. The third plate 30 is provided with a third boss 34, and the specific structure of which is the same as the boss of the first plate 10. The fourth plate 40 is provided with a fourth boss 44, and the specific structure of which is the same as the boss of the second plate 20, and so on. A gap is provided between the first corner hole 100 and the second corner hole 200 of the first plate 10 and the first corner hole 100 and the second corner hole 200 of the second plate 20 to communicate the first flow passage 3 with the first corner duct 6 and the second corner duct 7. The top of the first boss 14 around the third corner hole 300 or the fourth corner hole 400 of the first plate 10 and the first inner base portion 211 around the second corner hole 300 or the fourth corner hole 400 of the second plate 20 are arranged in a sealed manner. The top of the second boss 21 around the first corner hole 100 or the second corner hole 200 of the second plate 20 and the top of the convex portion 32 around the first corner hole 100 or the second corner hole 200 of the third plate 30 are arranged in a sealed manner. A gap is provided between the third corner hole 300 and the fourth corner hole 400 of the second plate 20 and the third corner hole 300 and the fourth corner hole 400 of the third plate 30 to communicate the second flow passage 4 with the third corner duct 8 and the fourth corner duct 9.

[0016] Alternatively, a part of heat-exchanging plates 2 may also have only two corner holes, three corner holes, or five corner holes, etc.. The different flow path configurations of the flow passages can be achieved according to different number of corner holes. The shapes of the corner holes may also be the same, for example, they are all circular.

[0017] It should be noted that the above provides a detailed introduction to the heat exchanger provided by the present application. Specific examples are used in this article to explain the principles and implementation methods of the present application, and the above examples are only used for understanding the core idea of the present application. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the scope of the claims of the present application.


Claims

1. A heat exchanger (1), comprising a heat-exchanging plate (2), wherein the heat-exchanging plate (2) comprises: a first plate (10), a second plate (20), and a third plate (30), and the second plate (20) is located between the first plate (10) and the third plate (30),

a first direction is defined to be perpendicular to a stacking direction of the heat-exchanging plate (2), wherein the heat exchanger (1) comprises a first side portion (110) and a second side portion (120), which are arranged on two opposite sides of the heat exchanger (1) in the first direction,

the heat exchanger (1) further comprises a first connecting portion (50) and a second connection portion (60), wherein the first connecting portion (50) is located on the first side portion (110) and the second connection portion (60) is located on the second side portion (120),

the first connecting portion (50), the second connection portion (60), the third plate (30), the first plate (10), and the second plate (20) are formed into an integrated structure.


 
2. The heat exchanger (1) according to claim 1, wherein a first flow passage (3) is formed between the first plate (10) and the second plate (20), the first plate (10) and the second plate (20) are arranged in a sealed manner, and an area sealed by the first plate (10) and the second plate (20) at least encloses the first flow passage (3),
a second flow passage (4) is formed between the second plate (20) and the third plate (30), the second plate (20) and the third plate (30) are arranged in a sealed manner, and an area sealed by the second plate (20) and the third plate (30) at least encloses the second flow passage (4).
 
3. The heat exchanger (1) according to claim 1 or 2, wherein the second plate (20) comprises a first base portion (21) and a first convex portion (22) protruding relative to the first base portion (21), and the first convex portion (22) is arranged around the second flow passage (4),
the first convex portion (22) and the third plate (30) are arranged in a sealed manner, and the first convex portion (22) and the first plate (10) are arranged in a sealed manner.
 
4. The heat exchanger (1) according to claim 3, wherein the first plate (10) comprises a second base portion (11) and a second convex portion (12) protruding relative to the second base portion (11), a protruding direction of the second convex portion (12) is opposite to a protruding direction of the first convex portion (22), and the second base portion (11) is arranged around the second convex portion (12),
the first base portion (21) comprises a first outer base portion (212), the first outer base portion (212) is arranged around the first convex portion (22), and the second base portion (11) and the first outer base portion (212) are arranged in a sealed manner.
 
5. The heat exchanger (1) according to claim 3, wherein the third plate (30) comprises a third base portion (31) and a third convex portion (32) protruding relative to the third base portion (31), a protruding direction of the third convex portion (32) is opposite to a protruding direction of the first convex portion (22),
the third base portion (31) is arranged around the third convex portion (32) and the first convex portion (22) and the third convex portion (32) are arranged in a sealed manner.
 
6. The heat exchanger (1) according to claim 4, wherein the second convex portion (12) is provided with a first convex portion (13) protruding towards the second plate (20), and the first base portion (21) comprises a first inner base portion (211), wherein the first convex portion (22) is arranged around the first inner base portion (211), and at least a part of the first convex portion (13) abuts against the first inner base portion (211).
 
7. The heat exchanger (1) according to claim 5, wherein the first base portion (21) comprises a first inner base portion (211), the first convex portion (22) is arranged around the first inner base portion (211),
the first inner base portion (211) is provided with a second convex portion (23) protruding towards the third plate (30), the third convex portion (32) is provided a third convex portion (33) protruding away from the second plate (20),and at least a part of the second convex portion (23) abuts against the third convex portion (32).
 
8. The heat exchanger (1) according to any one of claims 1 to 7, further comprising a first corner duct (6), a second corner duct (7), a third corner duct (8), and a fourth corner duct (9),
wherein the first flow passage (3) is in communication with the first corner duct (6) and the second corner duct (7), and the second flow passage (4) is in communication with the third corner duct (8) and the fourth corner duct (9).
 
9. The heat exchanger (1) according to any one of claims 1 to 7, further comprising a fourth plate (40) and a third connecting portion (70), wherein

the third plate (30) is located between the second plate (20) and the fourth plate (40), the third connecting portion (70) is located on the first side portion (110) of the heat exchanger (1), and the third connecting portion (70), the third plate (30), and the fourth plate (40) are formed into an integrated structure,

a third flow passage (5) is provided between the third plate (30) and the fourth plate (40), the third plate (30) and the fourth plate (40) are arranged in a sealed manner, and an area sealed by the third plate (30) and the fourth plate (40) at least encloses the third flow passage (5).


 
10. The heat exchanger (1) according to claim 9, further comprising a first corner duct (60), a second corner duct (7), a third corner duct (8), and a fourth corner duct (9), wherein
the first flow passage (3) is in communication with the first corner duct (6) and the second corner duct (7), the second flow passage (4) is in communication with the third corner duct (8) and the fourth corner duct (9), and the third flow passage (5) is in communication with the first corner duct (6) and the second corner duct (7).
 
11. The heat exchanger (1) according to claim 10, wherein the first plate (10) comprises a second base portion (11) and a second convex portion (12) protruding relative to the second base portion (11), the second base portion (11) is arranged around the second convex portion (12),

the second plate (20) comprises a first base portion (21) and a first convex portion (22) protruding relative to the first base portion (21), the first base portion (21) comprises a first inner base portion (211) and a first outer base portion (212), the first convex portion (22) is arranged around the first inner base portion (211) and the first outer base portion (212) is arranged around the first convex portion (22),

a protruding direction of the second convex portion (12) is opposite to a protruding direction of the first convex portion (22),

the third plate (30) comprises a third base portion (31) and a third convex portion (32) protruding relative to the third base portion (31), the third base portion (31) is arranged around the third convex portion (32), and a protruding direction of the third convex portion (32) is opposite to a protruding direction of the first convex portion (22),

the fourth plate (40) comprises a fourth base portion (41) and a fourth convex portion (42) protruding relative to the fourth base portion (41), wherein the fourth base portion (41) comprises a fourth inner base portion (411) and a fourth outer base portion (412), the fourth convex portion (42) is arranged around the fourth inner base portion (411), the fourth outer base portion (412) is arranged around the fourth convex portion (42), and a protruding direction of the fourth convex portion (42) is opposite to a protruding direction of the third convex portion (32),

the second base portion (11) and the first outer base portion (212) are arranged in a sealed manner, the first convex portion (22) and the third convex portion (32) are arranged in a sealed manner, and the third base portion (31) and the fourth outer base portion (412) are arranged in a sealed manner,

the second convex portion (12) is provided with a first convex portion (13) protruding towards the second plate (20), and at least a part of the first convex portion (13) abuts against the first inner base portion (211), wherein the first inner base portion (211) is provided with a second convex portion (23) protruding towards the third plate (30), and at least a part of the second convex portion (23) abuts against the third convex portion (32), wherein the third convex portion (32) is provided a third convex portion (33) protruding towards the fourth plate (40), and at least a part of the second convex portion (23) abuts against the fourth inner base portion (411).


 




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Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description