A multi-stage liquid cooling plate

Abstract

The utility model provides a multistage liquid cooling plate, including liquid cooling plate, one end of liquid cooling plate is equipped with liquid inlet, the other end of liquid cooling plate is equipped with liquid outlet, be equipped with the first stage liquid cooling pipeline, second stage liquid cooling pipeline and third stage liquid cooling pipeline of successive connection on liquid cooling plate, the inner wall of liquid cooling plate one end is equipped with front end pipeline, the inner wall of liquid cooling plate other end is equipped with tail end pipeline, the first stage liquid cooling pipeline penetrates front end pipeline, third stage liquid cooling pipeline with tail end pipeline is penetrated, tail end pipeline with liquid outlet is penetrated.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to a multi-stage liquid cooling plate. Background Technology

[0002] With the increase in energy density of power batteries and the development of fast charging technology, the thermal stability of batteries faces more stringent challenges, making the battery cooling system a key factor in the development of electric vehicles. To ensure that power batteries operate within a suitable temperature range, the battery thermal management system has become a core subsystem of electric vehicles. The battery thermal management system mainly consists of a cooling system, a heating system, temperature sensors, and a control unit. During charging and discharging, the internal chemical reactions of the power battery rapidly generate a large amount of heat, causing the battery temperature to rise rapidly. Therefore, heating the battery under low-temperature conditions is relatively easy to achieve.

[0003] Current mainstream battery heating systems utilize pulsed self-discharge cycles to rapidly bring the battery to a suitable operating temperature in low-temperature environments. Optimizing battery heat dissipation technology plays a crucial role in improving battery range, ensuring safety performance, and promoting the industrialization of electric vehicles. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing a multi-stage liquid cooling plate that improves the heat dissipation performance of the battery pack.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This utility model provides a multi-stage liquid cooling plate, including a liquid cooling plate, one end of which is provided with a liquid inlet and the other end of which is provided with a liquid outlet. The liquid cooling plate is provided with a first-stage liquid cooling pipe, a second-stage liquid cooling pipe and a third-stage liquid cooling pipe connected in sequence. The inner wall of one end of the liquid cooling plate is provided with a front-end pipe and the inner wall of the other end of the liquid cooling plate is provided with a tail-end pipe. The first-stage liquid cooling pipe passes through the front-end pipe, the third-stage liquid cooling pipe passes through the tail-end pipe, and the tail-end pipe passes through the liquid outlet.

[0006] Furthermore, the primary liquid cooling pipeline includes a primary main pipeline, which is connected to the liquid inlet, and the two sides of the middle section of the primary main pipeline are respectively connected to a first primary side pipeline and a second primary side pipeline.

[0007] Furthermore, the angle between the first-level side pipe and the second-level side pipe and the first-level main pipe is 45 degrees to 50 degrees; and the first-level side pipe and the second-level side pipe are symmetrically arranged with the first-level main pipe as the axis of symmetry. Both the first-stage side pipe and the second-stage side pipe are spaced apart from the inner wall of the liquid cooling plate.

[0008] Furthermore, the end of the primary main pipeline is split into a first secondary main pipeline and a second secondary main pipeline; The first and second-level main pipelines include an inclined section and a straight section of the first and second-level main pipelines that are connected to each other. The second and second-level main pipelines include interconnected inclined and straight sections. The first secondary main pipeline inclined pipe is parallel to the first primary side pipeline, and the second secondary main pipeline inclined pipe is parallel to the second primary side pipeline; Both the first and second secondary main pipelines are parallel to the primary main pipeline.

[0009] Furthermore, the first secondary main pipeline is connected to the first secondary side pipeline and the second secondary side pipeline on both sides of the middle section of the first secondary main pipeline, and the second secondary main pipeline is connected to the third secondary side pipeline and the fourth secondary side pipeline on both sides of the middle section of the second secondary main pipeline. The first secondary side pipe is parallel to the first primary side pipe, and the second secondary side pipe is parallel to the second primary side pipe; The third secondary side pipe is parallel to the first primary side pipe, and the fourth secondary side pipe is parallel to the second primary side pipe; The second and third secondary side pipes, the third secondary side pipe, and the second through pipe are connected, and the second through pipe is parallel to the primary main pipe; The first secondary side pipe and the fourth secondary side pipe are evenly spaced from the liquid cooling plate.

[0010] Furthermore, the end of the first secondary main pipeline straight pipe splits into a first tertiary main pipeline inclined pipe and a second tertiary main pipeline inclined pipe; the first tertiary main pipeline inclined pipe is connected to the first tertiary main pipeline straight pipe, and the second tertiary main pipeline inclined pipe is connected to the second tertiary main pipeline straight pipe. The end of the second and third level main pipeline straight pipe splits into a third and third level main pipeline inclined pipe and a fourth and third level main pipeline inclined pipe; the third and third level main pipeline inclined pipe is connected to the third and third level main pipeline straight pipe, and the fourth and third level main pipeline inclined pipe is connected to the fourth and third level main pipeline straight pipe.

[0011] Furthermore, the first and third-level main pipeline inclined pipes and the third and third-level main pipeline inclined pipes are both parallel to the first-level side pipeline, and the second and third-level main pipeline inclined pipes and the fourth and third-level main pipeline inclined pipes are both parallel to the second-level side pipeline. The first and third level main pipeline straight sections, the second and third level main pipeline straight sections, the third and fourth level main pipeline straight sections, and the fourth level main pipeline straight section are all parallel to the first level main pipeline.

[0012] Furthermore, multiple first- and third-level side pipes and multiple second- and third-level side pipes are respectively connected to both sides of the first- and third-level main pipeline. The second and third level main pipelines are connected to multiple third level side pipelines and multiple fourth level side pipelines on both sides of the straight pipeline. The third-level main pipeline is connected to multiple fifth-level side pipelines and multiple sixth-level side pipelines on both sides of its straight pipe. The fourth-level main pipeline is connected to multiple seventh-level side pipelines and multiple eighth-level side pipelines on both sides of the straight pipeline. The first third-level side pipe, the third third-level side pipe, the fifth third-level side pipe, and the seventh third-level side pipe are all parallel to the first first-level side pipe; The second and third-level side pipes, the fourth and sixth third-level side pipes, and the eighth third-level side pipes are all parallel to the second-level side pipes.

[0013] Furthermore, multiple first-stage third-stage side pipes and multiple eighth-stage third-stage side pipes are all spaced apart from the inner sidewall of the liquid cooling plate; Multiple second and third-level side pipes, multiple third and third-level side pipes, and the first through pipe are connected to each other; The sixth and third-level side pipes, the seventh and third-level side pipes, and the third through pipe are connected to each other; Both the first through pipe and the third through pipe are parallel to the primary main pipe.

[0014] The beneficial effects of this invention are: the multi-stage liquid cooling plate increases the heat transfer coefficient and reduces the pressure drop by continuously grading the liquid cooling plate. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a multi-stage liquid cooling plate. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0017] Please see Figure 1A multi-stage liquid cooling plate includes a liquid cooling plate 1, with an inlet 101 at one end and an outlet 102 at the other end. The liquid cooling plate 1 is provided with sequentially connected primary, secondary, and tertiary liquid cooling pipes. A front-end pipe 901 is provided on the inner wall of one end of the liquid cooling plate 1, and a rear-end pipe 902 is provided on the inner wall of the other end. The primary liquid cooling pipes pass through the front-end pipe 901, and the tertiary liquid cooling pipes communicate with the rear-end pipe 902. The rear-end pipe 902 communicates with the outlet 102.

[0018] In one specific embodiment, the liquid outlet 102 is located in the middle of one end of the liquid cooling plate 1. The liquid outlet 102 is connected to the first-stage liquid cooling pipe, the first-stage liquid cooling pipe is connected to the second-stage liquid cooling pipe, the second-stage liquid cooling pipe is connected to the third-stage liquid cooling pipe, and the outlet end of the third-stage liquid cooling pipe is connected to the liquid outlet 102. In one specific embodiment, the diameter of the liquid outlet 102 is the same as the diameter of the primary main pipe 301, and the primary main pipe 301 is parallel to the length direction of the liquid cooling plate 1.

[0019] The primary liquid cooling pipeline includes a primary main pipeline 301, which is connected to the liquid inlet 101. The two sides of the middle part of the primary main pipeline 301 are respectively connected to a first primary side pipeline 302 and a second primary side pipeline 303.

[0020] The angle between the first primary side pipe 302 and the second primary side pipe 303 and the primary main pipe 301 is 45 degrees to 50 degrees; and the first primary side pipe 302 and the second primary side pipe 303 are symmetrically arranged with the primary main pipe 301 as the axis of symmetry. In one specific embodiment, the diameter of the second-stage side pipe 303 is larger than the diameter of the first-stage side pipe 302 and the second-stage side pipe 303. In one specific embodiment, the first-stage side pipe 302 and the second-stage side pipe 303 are spaced a certain distance from the inner wall of the liquid cooling plate 1. The width of this distance is consistent with the width of the first-stage side pipe 302 and the second-stage side pipe 303, for the flow of coolant.

[0021] The first-stage side pipe 302 and the second-stage side pipe 303 are both spaced apart from the inner side wall of the liquid cooling plate 1.

[0022] The end of the primary main pipeline 301 splits into a first secondary main pipeline 401 and a second secondary main pipeline; That is, the primary main pipeline 301 is split into two, becoming a secondary liquid-cooled pipeline; The first secondary main pipeline includes a first secondary main pipeline inclined pipe 4011 and a first secondary main pipeline straight pipe 4012 that are connected to each other; The second and second-level main pipelines include the connected second and second-level main pipeline inclined pipe 4021 and the second and second-level main pipeline straight pipe 4022; The first secondary main pipeline inclined pipe 4011 is parallel to the first primary side pipe 302, and the second secondary main pipeline inclined pipe 4021 is parallel to the second primary side pipe 303; Both the first secondary main pipeline straight pipe 4012 and the second secondary main pipeline straight pipe 4022 are parallel to the primary main pipeline 301.

[0023] The first secondary main pipeline straight pipe 4012 is connected to the first secondary side pipe 501 and the second secondary side pipe 502 on both sides of the middle section, and the second secondary main pipeline straight pipe 4022 is connected to the third secondary side pipe 503 and the fourth secondary side pipe 504 on both sides of the middle section. The first secondary side pipe 501 is parallel to the first primary side pipe 302, and the second secondary side pipe 502 is parallel to the second primary side pipe 303; The third secondary side pipe 503 is parallel to the first primary side pipe 302, and the fourth secondary side pipe 504 is parallel to the second primary side pipe 303; The second secondary side pipe 502, the third secondary side pipe 503, and the second through pipe 602 are connected, and the second through pipe 602 is parallel to the primary main pipe 301. The first secondary side pipe 501 and the fourth secondary side pipe 504 are evenly spaced from the liquid cooling plate 1.

[0024] In one specific embodiment, the distance between the first secondary side pipe 501 and the inner wall of the liquid cooling plate 1 is equal to the distance between the fourth secondary side pipe 504 and the inner wall of the liquid cooling plate 1, and this distance is consistent with that between the first secondary side pipe 501 and the fourth secondary side pipe 504.

[0025] In one specific implementation, the diameters of the first and second secondary main pipeline inclined pipes 4011, the second and second secondary main pipeline inclined pipes 4021, the first and second secondary main pipeline straight pipes 4012 and the second and second secondary main pipeline straight pipes 4022 are the same and are all smaller than the first primary main pipeline 301.

[0026] In one specific implementation, the diameters of the first secondary side pipe 501, the second secondary side pipe 502, the third secondary side pipe 503, and the fourth secondary side pipe 504 are the same and are all smaller than the first primary side pipe 302.

[0027] The end of the first secondary main pipeline straight pipe 4012 splits into the first tertiary main pipeline inclined pipe 7011 and the second tertiary main pipeline inclined pipe 7012; the first tertiary main pipeline inclined pipe 7011 is connected to the first tertiary main pipeline straight pipe 7021, and the second tertiary main pipeline inclined pipe 7012 is connected to the second tertiary main pipeline straight pipe 7022. The end of the second and third level main pipeline straight pipe 4022 splits into a third and third level main pipeline inclined pipe 7013 and a fourth and third level main pipeline inclined pipe 7014; the third and third level main pipeline inclined pipe 7013 is connected to the third and third level main pipeline straight pipe 7023, and the fourth and third level main pipeline inclined pipe 7014 is connected to the fourth and third level main pipeline straight pipe 7024.

[0028] In one specific implementation, the first and second-level main pipeline straight pipe 4012 is split in two, becoming one half of the tertiary liquid-cooled pipeline, and the second and second-level main pipeline straight pipe 4022 is split in two, becoming the other half of the tertiary liquid-cooled pipeline.

[0029] The first and third-level main pipeline inclined pipes 7011 and 7013 are both parallel to the first-level side pipe 302, and the second and third-level main pipeline inclined pipes 7012 and 7014 are both parallel to the second-level side pipe 303. The first and third-level main pipeline straight pipes 7021, 7022, 7023, and 7024 are all parallel to the first-level main pipeline 301.

[0030] The first and third-level main pipeline 7021 is connected to multiple first and third-level side pipelines 801 and multiple second and third-level side pipelines 802 on both sides respectively. The second and third level main pipeline straight pipe 7022 is connected to multiple third level side pipes 803 and multiple fourth level side pipes 804 on both sides respectively; The third-level main pipeline 7023 is connected to multiple fifth-level side pipelines 805 and multiple sixth-level side pipelines 806 on both sides. The fourth-level main pipeline 7024 is connected to multiple seventh-level side pipelines 807 and multiple eighth-level side pipelines 808 on both sides. The first tertiary side pipe 801, the third tertiary side pipe 803, the fifth tertiary side pipe 805 and the seventh tertiary side pipe 807 are all parallel to the first primary side pipe 302; The second and third-level side pipes 802, the fourth and third-level side pipes 804, the sixth and eighth third-level side pipes 806 and 808 are all parallel to the second and first-level side pipes 303.

[0031] Multiple first-level third-stage side pipes 801 and multiple eighth-level third-stage side pipes 808 are all spaced apart from the inner sidewall of the liquid cooling plate 1; In one specific embodiment, the spacing between the plurality of first-level third-stage side pipes 801 and the inner wall of the liquid cooling plate 1 and the spacing between the plurality of eighth-level third-stage side pipes 808 and the inner wall of the liquid cooling plate 1 are consistent, and the spacing is consistent with the pipe diameter of the first-level third-stage side pipes 801 and the eighth-level third-stage side pipes 808.

[0032] Multiple second and third-level side pipes 802, multiple third and third-level side pipes 803, and the first through pipe 601 are connected together; The plurality of the sixth-level third-stage side pipes 806, the plurality of the seventh-level third-stage side pipes 807, and the third through pipe 603 are connected together; Both the first through pipe 601 and the third through pipe 603 are parallel to the primary main pipe 301.

[0033] In one specific embodiment, the diameters of the first and third-level main pipeline inclined pipes 7011, 7012, 7013, and 7014, and the first and fourth-level main pipeline straight pipes 7021, 7022, 7023, and 7024 are consistent. Furthermore, they are all aligned with the length direction of the liquid cooling plate 1.

[0034] In one specific implementation, the first tertiary side pipe 801, the second tertiary side pipe 802, the third tertiary side pipe 803, the fourth tertiary side pipe 804, the fifth tertiary side pipe 805, the sixth tertiary side pipe 806, the seventh tertiary side pipe 807, and the eighth tertiary side pipe 808 have the same diameter, and are all smaller than the first and second tertiary side pipe 501.

[0035] In one specific embodiment, the coolant is a CuO nanofluid coolant.

[0036] In one specific implementation, a multi-stage liquid cooling plate covers the surface of the battery pack for cooling the surface of the battery pack.

[0037] The flow process of coolant in a multi-stage liquid cooling plate is as follows: After entering through the inlet 101, the coolant flows to both sides of the front-end pipe 901 and the primary main pipe 301. After flowing through both sides of the front-end pipe 901, the coolant flows to the inner wall of the liquid cooling plate 1 along its length, where it merges with the coolant flowing through the primary main pipe 301, the first primary side pipe 302, and the second primary side pipe 303. The merged coolant continues to flow along the inner wall of the liquid cooling plate 1 along its length, and then merges with the coolant flowing out of the first secondary side pipe 501 and the fourth secondary side pipe 504. It continues to flow along the inner wall of the liquid cooling plate 1 along its length, and then merges with the coolant flowing out of multiple first tertiary side pipes 801 and the eighth tertiary side pipe 808 before flowing into the tail pipe 902 and out through the outlet 102.

[0038] In addition, part of the coolant in the primary main pipe 301 flows into the first primary side pipe 302 and the second primary side pipe 303, and the other part flows into the first secondary main pipe inclined pipe 4011 and the second secondary main pipe inclined pipe 4021 respectively after passing through the primary main pipe 301. The coolant flowing through the inclined pipe 4011 of the first and second secondary main pipelines flows into the straight pipe 7021 of the first and third secondary main pipelines and the straight pipe 7022 of the second and third secondary main pipelines respectively through the straight pipe 4012 of the first and second secondary main pipelines. The coolant flowing through the inclined pipe 4021 of the second and second-level main pipeline flows through the straight pipe 4022 of the second and second-level main pipeline into the straight pipe 7023 of the third and third-level main pipeline and the straight pipe 7024 of the fourth and third-level main pipeline, respectively. As the coolant in the first and third-level main straight pipe 7021 flows toward the outlet 102, it continuously flows into multiple first and third-level side pipes 801 and multiple second and third-level side pipes 802 on both sides. After passing through the gaps in the inner wall and the first through pipe 601, it flows into the tail pipe 902 and then flows out from the outlet 102.

[0039] The coolant flow pattern in the second and third level main pipeline straight pipes 7022, the third and fourth level main pipeline straight pipes 7023 and the fourth level main pipeline straight pipe 7024 is the same as that in the first level main pipeline straight pipe 7021, so it will not be repeated.

[0040] Table 1 shows the comparison of optimization effects. Compared with before optimization, the pressure drop and heat transfer coefficient have been improved.

[0041] Table 1 Comparison of Optimization Effects

[0042] The embodiments described above merely illustrate the implementation of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be defined by the appended claims.

Claims

1. A multi-stage liquid cooling plate, characterized in that: The system includes a liquid cooling plate (1), one end of which is provided with an inlet (101) and the other end of which is provided with an outlet (102). The liquid cooling plate (1) is provided with a first-stage liquid cooling pipe, a second-stage liquid cooling pipe and a third-stage liquid cooling pipe connected in sequence. The inner wall of one end of the liquid cooling plate (1) is provided with a front-end pipe (901) and the inner wall of the other end of the liquid cooling plate (1) is provided with a tail-end pipe (902). The first-stage liquid cooling pipe passes through the front-end pipe (901), the third-stage liquid cooling pipe passes through the tail-end pipe (902), and the tail-end pipe (902) passes through the outlet (102).

2. The multi-stage liquid cooling plate according to claim 1, characterized in that: The primary liquid cooling pipeline includes a primary main pipeline (301), which is connected to the liquid inlet (101). The two sides of the middle part of the primary main pipeline (301) are respectively connected to a first primary side pipeline (302) and a second primary side pipeline (303).

3. A multi-stage liquid cooling plate according to claim 2, characterized in that: The angle between the first primary side pipe (302) and the second primary side pipe (303) and the primary main pipe (301) is 45 degrees to 50 degrees; and the first primary side pipe (302) and the second primary side pipe (303) are symmetrically arranged with the primary main pipe (301) as the axis of symmetry. The first-stage side pipe (302) and the second-stage side pipe (303) are both spaced apart from the inner wall of the liquid cooling plate (1).

4. A multi-stage liquid cooling plate according to claim 2, characterized in that: The end of the primary main pipeline (301) is split into a first secondary main pipeline and a second secondary main pipeline; The first secondary main pipeline includes a first secondary main pipeline inclined pipe (4011) and a first secondary main pipeline straight pipe (4012) that are connected to each other. The second and second-level main pipelines include the connected second and second-level main pipeline inclined pipe (4021) and the second and second-level main pipeline straight pipe (4022). The first secondary main pipeline inclined pipe (4011) is parallel to the first primary side pipe (302), and the second secondary main pipeline inclined pipe (4021) is parallel to the second primary side pipe (303); Both the first secondary main pipeline straight pipe (4012) and the second secondary main pipeline straight pipe (4022) are parallel to the primary main pipeline (301).

5. A multi-stage liquid cooling plate according to claim 4, characterized in that: The first secondary main pipeline straight pipe (4012) is connected to the first secondary side pipe (501) and the second secondary side pipe (502) on both sides of the middle section, and the second secondary main pipeline straight pipe (4022) is connected to the third secondary side pipe (503) and the fourth secondary side pipe (504) on both sides of the middle section. The first secondary side pipe (501) is parallel to the first primary side pipe (302), and the second secondary side pipe (502) is parallel to the second primary side pipe (303); The third secondary side pipe (503) is parallel to the first primary side pipe (302), and the fourth secondary side pipe (504) is parallel to the second primary side pipe (303); The second secondary side pipe (502), the third secondary side pipe (503), and the second through pipe (602) are connected, and the second through pipe (602) is parallel to the primary main pipe (301); The first secondary side pipe (501) and the fourth secondary side pipe (504) are evenly spaced from the liquid cooling plate (1).

6. A multi-stage liquid cooling plate according to claim 4, characterized in that: The end of the first secondary main pipeline straight pipe (4012) splits into the first tertiary main pipeline inclined pipe (7011) and the second tertiary main pipeline inclined pipe (7012); the first tertiary main pipeline inclined pipe (7011) is connected to the first tertiary main pipeline straight pipe (7021), and the second tertiary main pipeline inclined pipe (7012) is connected to the second tertiary main pipeline straight pipe (7022); The end of the second-level main pipeline straight pipe (4022) splits into the third-level main pipeline inclined pipe (7013) and the fourth-level main pipeline inclined pipe (7014); the third-level main pipeline inclined pipe (7013) is connected to the third-level main pipeline straight pipe (7023), and the fourth-level main pipeline inclined pipe (7014) is connected to the fourth-level main pipeline straight pipe (7024).

7. A multi-stage liquid cooling plate according to claim 6, characterized in that: The first and third-level main pipeline inclined pipes (7011) and the third and third-level main pipeline inclined pipes (7013) are both parallel to the first-level side pipe (302), and the second and third-level main pipeline inclined pipes (7012) and the fourth and third-level main pipeline inclined pipes (7014) are both parallel to the second-level side pipe (303). The first and third-level main pipeline straight pipes (7021), the second and third-level main pipeline straight pipes (7022), the third and third-level main pipeline straight pipes (7023), and the fourth and third-level main pipeline straight pipes (7024) are all parallel to the first-level main pipeline (301).

8. A multi-stage liquid cooling plate according to claim 7, characterized in that: The first and third-level main pipeline straight pipe (7021) is connected to multiple first and third-level side pipes (801) and multiple second and third-level side pipes (802) on both sides respectively. The second and third level main pipeline straight pipe (7022) is connected to multiple third level side pipes (803) and multiple fourth level side pipes (804) on both sides respectively. The third-level main pipeline (7023) is connected to multiple fifth-level side pipelines (805) and multiple sixth-level side pipelines (806) on both sides. The fourth-level main pipeline (7024) is connected to multiple seventh-level side pipelines (807) and multiple eighth-level side pipelines (808) on both sides. The first third-level side pipe (801), the third third-level side pipe (803), the fifth third-level side pipe (805) and the seventh third-level side pipe (807) are all parallel to the first first-level side pipe (302); The second and third-level side pipes (802), the fourth and third-level side pipes (804), the sixth and eighth third-level side pipes (806) are all parallel to the second and first-level side pipes (303).

9. A multi-stage liquid cooling plate according to claim 8, characterized in that: Multiple first-level third-stage side pipes (801) and multiple eighth-level third-stage side pipes (808) are spaced apart from the inner wall of the liquid cooling plate (1); Multiple second and third-level side pipes (802), multiple third and third-level side pipes (803), and the first through pipe (601) are connected to each other; Multiple sixth-level third-level side pipes (806), multiple seventh-level third-level side pipes (807), and the third through pipe (603) are connected to each other; Both the first through pipe (601) and the third through pipe (603) are parallel to the primary main pipe (301).

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