Porous channel heat dissipation structure matched with bipolar plate of hydrogen fuel cell

Abstract

The invention relates to the technical field of hydrogen fuel cells, in particular to a porous channel heat dissipation structure matched with a bipolar plate of a hydrogen fuel cell, the porous channel heat dissipation structure comprises a sealing outer frame and a bipolar plate body, the interior of the sealing outer frame is fixedly connected with the outer wall of the bipolar plate body, the bipolar plate body comprises an anode single plate and a cathode single plate, a working gas inlet hole is formed in the outer wall of the top of the bipolar plate body; the cooling device has the beneficial effects that uniform mixing of ethylene glycol and the cooling liquid is further improved by stirring the cooling liquid, meanwhile, the flowing speed and turbulivity of the cooling liquid can be increased by stirring the cooling liquid, heat can be taken away more quickly by the cooling liquid, slow flowing of the cooling liquid in the cooling tank is avoided, and the cooling effect is improved. Correspondingly, the flow velocity of the cooling liquid is increased through the arrangement of the rotating blades, so that the effect that the cooling liquid drives heat on the bipolar plate body is improved, and bubbles generated by ethylene glycol can be broken through the shearing acting force of the rotating blades and are converted into smaller bubbles.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen fuel cells, and in particular to a porous channel heat dissipation structure adapted to a bipolar plate of a hydrogen fuel cell. Background Art

[0002] As the core component of fuel cells, hydrogen fuel cell bipolar plates play many important roles, including supporting the membrane electrode structure, separating hydrogen and oxygen, collecting electrons, conducting heat, providing hydrogen and oxygen channels, discharging water generated by the reaction, and providing coolant channels. In the design of hydrogen fuel cell bipolar plates, the heat dissipation structure is crucial, as it helps ensure the efficient operation and long-term stability of the battery.

[0003] The patent application publication number is CN111668506B, which discloses a new type of hydrogen fuel cell metal bipolar plate. The metal bipolar plate improves the structure of the flow channel transition zone and optimizes the detailed structural dimensions of the bipolar plate, increases the sealing line area, and makes the circulation and distribution of fuel, oxidant and coolant between the anode plate and the cathode plate more uniform.

[0004] In the prior art, there is a limitation in the design of the cooling trough, in that the bottom thereof remains flat without a slope, which results in a relatively slow flow rate of the coolant in the trough. The slow flow of the coolant means that the rate at which heat is transferred from the cooled object to the coolant is slowed down, thereby affecting the overall cooling efficiency, causing the temperature of the cooled object to rise, and failing to achieve the desired cooling effect. Summary of the invention

[0005] The purpose of the present invention is to provide a porous channel heat dissipation structure compatible with a hydrogen fuel cell bipolar plate to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: the hydrogen fuel cell bipolar plate comprises: a sealing outer frame and a bipolar plate body, the interior of the sealing outer frame is fixedly connected to the outer wall of the bipolar plate body, the bipolar plate body comprises an anode plate and a cathode plate, the outer wall at the top of the bipolar plate body is provided with a working gas inlet hole, the outer wall at the top of the bipolar plate body is provided with a working gas outlet hole, the outer wall at the top of the bipolar plate body is provided with a working gas channel, the outer wall at one end of the working gas channel is fixedly connected with the outer wall on one side of the working gas inlet hole, the outer wall at the other end of the working gas channel is fixedly connected with the outer wall on one side of the working gas outlet hole, the outer wall at the top of the bipolar plate body is provided with a sealing area, the structure of the bottom of the bipolar plate body is the same as the structure of the top of the bipolar plate body, and a heat dissipation plate is provided inside the middle of the bipolar plate body.

[0007] Preferably, a cooling groove is provided on the heat exhaust plate, a coolant inlet is fixedly connected to the outer wall at one end of the cooling groove, a coolant outlet is fixedly connected to the outer wall at the other end of the cooling groove, a diverter plate is fixedly connected to the interior of the cooling groove, and a disturbance mechanism is arranged inside the cooling groove.

[0008] Preferably, the plurality of disturbance mechanisms comprise a mounting rod, wherein the upper and lower sides of the mounting rod are respectively fixedly connected to the interior of the cooling groove, a cross section is arranged in the middle of the mounting rod, a circular groove is opened on the outer wall on the opposite side of the two cross sections, and an elliptical cylinder is rotatably connected inside the two circular grooves.

[0009] Preferably, the outer wall of the mounting rod is provided with grooves, the interiors of two of the grooves are rotatably connected with a rotating sleeve, and the outer wall of the rotating sleeve is fixedly connected with a rotating blade.

[0010] Preferably, a sealing shell is fixedly connected to one end of the inner wall of the cooling groove near the coolant inlet, a support rod is fixedly connected to the inner wall of the cooling groove near the bottom of the sealing shell, and a torsion spring is provided on the outer wall of the support rod.

[0011] Preferably, a baffle is provided on the outer wall of the torsion spring, the interior of the baffle is rotatably connected to the outer wall of the support rod, and an elastic strip is fixedly connected below the inner wall of the cooling groove.

[0012] Preferably, the outer wall on one side of the elastic strip is in movably contact with the outer wall of the baffle, and the interior of the sealing shell is rotatably connected to the upper side of the outer wall of the baffle.

[0013] Preferably, an exhaust groove is fixedly connected above one end of the cooling groove near the coolant outlet, the outer wall of the exhaust groove is connected through the interior of the bipolar plate body, the interior of the exhaust groove is slidably connected with a T-shaped sealing cover, the outer wall of the bottom of the T-shaped sealing cover is fixedly connected to an elastic block, and the outer wall of the bottom of the elastic block is fixedly connected to the bottom of the inner wall of the exhaust groove.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The porous channel heat dissipation structure proposed in the present invention, which is compatible with the bipolar plate of the hydrogen fuel cell, further increases the uniform mixing of ethylene glycol and the coolant by stirring the coolant. At the same time, stirring the coolant can also increase its flow velocity and turbulence, which helps the coolant to take away heat faster and avoids the slow flow of the coolant inside the cooling tank. Correspondingly, the flow velocity of the coolant is increased by the setting of the rotating blades, thereby improving the effect of the coolant in driving the heat on the bipolar plate body. The rotating blades have a shear force, which can also break the bubbles generated by the ethylene glycol and convert them into smaller bubbles. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the heat exhaust plate structure of the present invention; Figure 3 For the present invention Figure 2 A is an enlarged schematic diagram of the structure at location A; Figure 4 This is a schematic diagram of the rotating blade structure of the present invention; Figure 5 This is a schematic diagram of the internal structure of the rotating sleeve of the present invention; Figure 6 This is a schematic diagram of the mounting rod structure of the present invention; Figure 7 It is a schematic diagram of the structure of the rotating sleeve of the present invention; Figure 8 This is a schematic diagram of the sealing shell structure of the present invention; Fig. 9 It is a schematic diagram of the internal structure of the exhaust groove of the present invention.

[0015] In the figure: 1. Sealing outer frame; 11. Bipolar plate body; 12. Working gas channel; 13. Sealing area; 14. Working gas inlet hole; 15. Working gas outlet hole; 2. Coolant inlet; 21. Coolant outlet; 23. Heat exhaust plate; 24. Cooling groove; 25. Diverter plate; 3. T-shaped sealing cover; 31. Exhaust groove; 32. Elastic block; 4. Support rod; 41. Sealing shell; 42. Torsion spring; 43. Baffle; 44. Elastic strip; 5. Rotating blade; 51. Mounting rod; 52. Rotating sleeve; 53. Elastic pad; 54. Elliptical cylinder. DETAILED DESCRIPTION

[0016] In order to make the purpose and technical solution of the present invention clearly and completely described, and the advantages more clearly understood, the embodiments of the present invention are further described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] For example, see Figure 1-Figure 9The present invention provides a technical solution of a porous channel heat dissipation structure compatible with a hydrogen fuel cell bipolar plate: the hydrogen fuel cell bipolar plate comprises: a sealing outer frame 1 and a bipolar plate body 11, the interior of the sealing outer frame 1 is fixedly connected to the outer wall of the bipolar plate body 11, the bipolar plate body 11 comprises an anode single plate and a cathode single plate, the outer wall at the top of the bipolar plate body 11 is provided with a working gas inlet hole 14, the outer wall at the top of the bipolar plate body 11 is provided with a working gas outlet hole 15, the outer wall at the top of the bipolar plate body 11 is provided with a working gas channel 12, the outer wall at one end of the working gas channel 12 is fixedly connected with the outer wall on one side of the working gas inlet hole 14, the outer wall at the other end of the working gas channel 12 is fixedly connected with the outer wall on one side of the working gas outlet hole 15, the outer wall at the top of the bipolar plate body 11 is provided with a sealing area 13, the structure at the bottom of the bipolar plate body 11 is the same as the structure at the top of the bipolar plate body 11, and a heat dissipation plate 23 is provided inside the middle of the bipolar plate body 11.

[0018] The working gas enters the working gas channel 12 on the bipolar plate body 11 through the working gas inlet hole 14 and is then evenly distributed to each reaction area. In the reaction area, hydrogen and oxygen undergo an electrochemical reaction under the action of the catalyst to generate electricity and water. The waste gas after the reaction is discharged through the outlet hole. At the same time, the coolant circulates through the cooling groove 24 to take away the heat generated by the reaction and keep the fuel cell within a suitable operating temperature range. The basic requirement for heat dissipation of the bipolar plate body 11 is achieved through the setting of the coolant.

[0019] Embodiment 2, on the basis of embodiment 1, an inner wall of the cooling groove 24 is fixedly connected to a sealing shell 41 at one end near the coolant inlet 2, an inner wall of the cooling groove 24 is fixedly connected to a support rod 4 near the bottom of the sealing shell 41, an outer wall of the support rod 4 is provided with a torsion spring 42, an outer wall of the torsion spring 42 is provided with a baffle 43, the interior of the baffle 43 is rotatably connected to the outer wall of the support rod 4, an elastic strip 44 is fixedly connected to the bottom of the inner wall of the cooling groove 24, an outer wall on one side of the elastic strip 44 is in active contact with the outer wall of the baffle 43, and the interior of the sealing shell 41 is rotatably connected to the top of the outer wall of the baffle 43.

[0020] The coolant is impacted by the reflux and mixed with ethylene glycol. As the coolant continues to flow in, the impact force generated pushes the baffle 43 to rotate. Then, through the rotation of the baffle 43, the baffle 43 can drive the torsion spring 42 to rotate on the support rod 4, so that the coolant drives the ethylene glycol into the interior of the cooling tank 24. The mixing of the coolant and ethylene glycol depends on the flow of the coolant and does not require an additional power source, so it has the characteristic of energy saving.

[0021] Embodiment 3, on the basis of embodiment 2, a cooling groove 24 is opened on the heat dissipation plate 23, the outer wall at one end of the cooling groove 24 is penetrated and fixedly connected with a coolant inlet 2, the outer wall at the other end of the cooling groove 24 is penetrated and fixedly connected with a coolant outlet 21, the interior of the cooling groove 24 is fixedly connected with a diverter plate 25, and a disturbance mechanism is arranged inside the cooling groove 24.

[0022] By adapting the cooling groove 24 to the hydrogen fuel cell bipolar plate, when the coolant flows along the guide of the cooling groove 24, it can quickly absorb the heat on the bipolar plate body 11 and take it away, which helps to reduce the temperature of the bipolar plate body 11 and prevent performance degradation or damage due to local overheating.

[0023] Embodiment 4, on the basis of embodiment 3, multiple disturbance mechanisms include a mounting rod 51, the upper and lower sides of the mounting rod 51 are respectively fixedly connected to the inside of the cooling groove 24, a cross section is arranged in the middle of the mounting rod 51, a circular groove is provided on the outer wall on the opposite side of the two cross sections, an elliptical cylinder 54 is rotatably connected to the inside of the two circular grooves, a groove is provided on the outer wall of the mounting rod 51, a rotating sleeve 52 is rotatably connected to the inside of the two grooves, and a rotating blade 5 is fixedly connected to the outer wall of the rotating sleeve 52.

[0024] By stirring the coolant, the uniform mixing of ethylene glycol and the coolant is further increased. At the same time, stirring the coolant can also increase its flow velocity and turbulence, which helps the coolant to take away heat faster and avoids the slow flow of the coolant in the cooling tank 24. Correspondingly, the flow velocity of the coolant is increased by the setting of the rotating blades 5, thereby improving the effect of the coolant in driving the heat on the bipolar plate body 11. The rotating blades 5 have a shear force, which can also break up the bubbles generated by ethylene glycol and convert them into smaller bubbles. As the bubbles are refined, their surface area increases, and the chance of contact with dissolved gases or impurities in the coolant increases, making them easier to eliminate.

[0025] Embodiment 5, on the basis of embodiment 4, an exhaust groove 31 is fixedly connected above one end of the cooling groove 24 near the coolant outlet 21, the outer wall of the exhaust groove 31 is connected through the interior of the bipolar plate body 11, the interior of the exhaust groove 31 is slidably connected with a T-shaped sealing cover 3, the outer wall of the bottom of the T-shaped sealing cover 3 is fixedly connected with an elastic block 32, and the outer wall of the bottom of the elastic block 32 is fixedly connected to the bottom of the inner wall of the exhaust groove 31.

[0026] When the gas inside the exhaust groove 31 gathers to a certain extent, the driving force of the gas can be used to push the T-shaped sealing cover 3 to the outside of the exhaust groove 31. When the T-shaped sealing cover 3 leaves the exhaust groove 31, the gas inside the coolant can be discharged, ensuring that the coolant fully fills every corner of the cooling groove 24, thereby improving the heat exchange efficiency and making the bipolar plate body 11 work more stably.

[0027] Embodiment 6, based on embodiment 4, an elastic pad 53 is fixedly connected to the inner wall of the rotating sleeve 52 near the mounting rod 51 , and the inner walls of the two elastic pads 53 are rotatably connected to the outer wall of the mounting rod 51 .

[0028] By arranging the elastic pad 53 inside the rotating sleeve 52, the vibration and impact generated when the rotating sleeve 52 rotates on the mounting rod 51 can be absorbed. At the same time, the softness of the elastic pad 53 can reduce the direct contact between the rotating sleeve 52 and the mounting rod 51, thereby reducing friction and wear, which helps to reduce the resistance during rotation, further improves the rotation efficiency of the rotating blade 5, and reduces the heat and noise generated by the friction between the rotating sleeve 52 and the mounting rod 51, so that the rotating sleeve 52 can rotate more smoothly on the mounting rod 51.

[0029] In actual use, when working, when the hydrogen fuel cell is running, the working gas enters the working gas channel 12 on the bipolar plate body 11 through the working gas inlet hole 14, and then is evenly distributed to each reaction area. In the reaction area, hydrogen and oxygen undergo an electrochemical reaction under the action of the catalyst to generate electricity and water. The waste gas after the reaction is discharged through the outlet hole. At the same time, the coolant circulates through the cooling groove 24 to take away the heat generated by the reaction and keep the fuel cell within a suitable operating temperature range.

[0030] It should be noted that the sealing area 13 is located at the edge of the bipolar plate body 11 to prevent the reaction gas from leaking to the outside of the fuel cell; the working gas inlet hole 14 set on the anode plate on the bipolar plate body 11 is the hydrogen inlet, and the working gas inlet hole 14 set on the cathode plate is the oxygen inlet.

[0031] Before the coolant enters the cooling tank 24, ethylene glycol is first poured into the coolant inlet 2. Due to the cooperation of the baffle 43 and the elastic strip 44, the ethylene glycol is intercepted, thereby preventing the ethylene glycol from entering the cooling tank 24 when it is not mixed with the coolant. Accordingly, by setting the baffle 43, the need for additional containers to mix the ethylene glycol can be reduced. At the same time, ethylene glycol has good thermal conductivity, which can help the coolant absorb and transfer heat faster. When ethylene glycol is mixed with the coolant, this thermal conductivity will be further enhanced. Therefore, the coolant with ethylene glycol added can more efficiently take away the heat generated by the bipolar plate body 11 during operation, ensuring the stable operation of the bipolar plate body 11.

[0032] By blocking the baffle 43 and the elastic strip 44 provided at the coolant inlet 2, when the coolant enters the cooling tank (24), the coolant is caused to produce a reflux state, and is mixed with ethylene glycol through the reflux impact of the coolant. As the coolant continues to flow in, the impact force generated pushes the baffle 43 to rotate, and then through the rotation of the baffle 43, the baffle 43 can drive the torsion spring 42 to rotate on the support rod 4, so that the coolant drives the ethylene glycol to enter the cooling tank 24. The mixing of the coolant and ethylene glycol depends on the flow of the coolant, and no additional power source is required, so it has the characteristic of energy saving.

[0033] By adapting the cooling groove 24 to the hydrogen fuel cell bipolar plate, when the coolant flows along the guide of the cooling groove 24, it can quickly absorb the heat on the bipolar plate body 11 and take it away, which helps to reduce the temperature of the bipolar plate body 11 and prevent performance degradation or damage due to local overheating.

[0034] By utilizing the flow of coolant in the cooling tank 24, the action of the fluid can be used to drive the rotating blade 5 to rotate, and then the rotating sleeve 52 can be driven by the rotating blade 5 to move, so that the coolant inside the cooling tank 24 can be stirred. By stirring the coolant, the uniform mixing of ethylene glycol and the coolant is further increased. At the same time, by stirring the coolant, its flow velocity and turbulence can also be increased, which helps the coolant to take away heat faster and avoids the slow flow of the coolant inside the cooling tank 24. Correspondingly, the setting of the rotating blade 5 increases the flow rate of the coolant, thereby improving the effect of the coolant on driving the heat on the bipolar plate body 11. The rotating blade 5 has a shearing force, which can also break the bubbles generated by ethylene glycol and convert them into smaller bubbles. As the bubbles become finer, their surface area increases, and the chance of contact with dissolved gases or impurities in the coolant increases, making them easier to eliminate.

[0035] It should be noted that the diverter plate 25 arranged in the cooling groove 24 at the position aligned with the coolant inlet 2 can direct the coolant entering the cooling groove 24 to flow to the two sides of the heat dissipation plate 23 through the diverter plate 25 .

[0036] By rotating the elliptical cylinder 54 inside the mounting rod 51, the contact area between the mounting rod 51 and the rotating sleeve 52 can be reduced. When the rotating sleeve 52 rotates on the mounting rod 51, the elliptical cylinder 54 can be driven to rotate on the mounting rod 51. The contact between the elliptical cylinder 54 and the mounting rod 51 and the rotating sleeve 52 is local, and the contact area is smaller, thereby reducing friction and wear during rotation. At the same time, the driving force required for the rotating blade 5 is smaller, and the rotation efficiency is higher, making it easier for the fluid to drive the rotating blade 5 to rotate.

[0037] By arranging the elastic pad 53 inside the rotating sleeve 52, the vibration and impact generated when the rotating sleeve 52 rotates on the mounting rod 51 can be absorbed. At the same time, the softness of the elastic pad 53 can reduce the direct contact between the rotating sleeve 52 and the mounting rod 51, thereby reducing friction and wear, which helps to reduce the resistance during rotation, further improves the rotation efficiency of the rotating blade 5, and reduces the heat and noise generated by the friction between the rotating sleeve 52 and the mounting rod 51, so that the rotating sleeve 52 can rotate more smoothly on the mounting rod 51.

[0038] When the coolant flows to the coolant outlet 21, due to the through connection between the exhaust groove 31 and the bipolar plate body 11, when the coolant drives the bubbles that have not been eliminated inside to pass through the exhaust groove 31, since the density of the gas is less than the density of the coolant, the gas rises into the exhaust groove 31. When the gas inside the exhaust groove 31 gathers to a certain extent, the driving force of the gas can be used to push the T-shaped sealing cover 3 toward the outside of the exhaust groove 31. When the T-shaped sealing cover 3 leaves the exhaust groove 31, the gas inside the coolant can be discharged, ensuring that the coolant fully fills every corner of the cooling groove 24, thereby improving the heat exchange efficiency and making the bipolar plate body 11 work more stably.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A porous channel heat dissipation structure adapted to a hydrogen fuel cell bipolar plate, characterized in that: The hydrogen fuel cell bipolar plate comprises: a sealing outer frame (1) and a bipolar plate body (11); the interior of the sealing outer frame (1) is fixedly connected to the outer wall of the bipolar plate body (11); the bipolar plate body (11) comprises an anode plate and a cathode plate; the top outer wall of the bipolar plate body (11) is provided with a working gas inlet hole (14); the top outer wall of the bipolar plate body (11) is provided with a working gas outlet hole (15); the top outer wall of the bipolar plate body (11) is provided with a working gas channel (12 ), the outer wall at one end of the working gas channel (12) is penetrated and fixedly connected with the outer wall on one side of the working gas inlet hole (14), the outer wall at the other end of the working gas channel (12) is penetrated and fixedly connected with the outer wall on one side of the working gas outlet hole (15), the outer wall at the top of the bipolar plate body (11) is provided with a sealing area (13), the structure of the bottom of the bipolar plate body (11) is the same as the structure of the top of the bipolar plate body (11), and a heat dissipation plate (23) is provided in the middle of the bipolar plate body (11).

2. The porous channel heat dissipation structure adapted to the hydrogen fuel cell bipolar plate according to claim 1, characterized in that: The heat exhaust plate (23) is provided with a cooling groove (24), an outer wall at one end of the cooling groove (24) is penetrated and fixedly connected with a cooling liquid inlet (2), an outer wall at the other end of the cooling groove (24) is penetrated and fixedly connected with a cooling liquid outlet (21), a flow divider plate (25) is fixedly connected inside the cooling groove (24), and a disturbance mechanism is provided inside the cooling groove (24).

3. The porous channel heat dissipation structure adapted to the hydrogen fuel cell bipolar plate according to claim 2, characterized in that: The plurality of disturbance mechanisms include a mounting rod (51), wherein the upper and lower sides of the mounting rod (51) are respectively fixedly connected to the inside of the cooling groove (24), a cross section is provided in the middle of the mounting rod (51), a circular groove is provided on the outer wall of the two opposite sides of the cross section, and an elliptical cylinder (54) is rotatably connected inside the two circular grooves.

4. The porous channel heat dissipation structure adapted to the bipolar plate of a hydrogen fuel cell according to claim 3, characterized in that: The outer wall of the mounting rod (51) is provided with a groove, the interior of two of the grooves is rotatably connected to a rotating sleeve (52), and the outer wall of the rotating sleeve (52) is fixedly connected to a rotating blade (5).

5. The porous channel heat dissipation structure adapted to the bipolar plate of a hydrogen fuel cell according to claim 2, characterized in that: A sealing shell (41) is fixedly connected to one end of the inner wall of the cooling groove (24) near the coolant inlet (2), a support rod (4) is fixedly connected to the inner wall of the cooling groove (24) near the bottom of the sealing shell (41), and a torsion spring (42) is provided on the outer wall of the support rod (4).

6. The porous channel heat dissipation structure adapted to the bipolar plate of a hydrogen fuel cell according to claim 5, characterized in that: The outer wall of the torsion spring (42) is provided with a baffle (43), the interior of the baffle (43) is rotatably connected to the outer wall of the support rod (4), and an elastic strip (44) is fixedly connected below the inner wall of the cooling groove (24).

7. The porous channel heat dissipation structure adapted to the bipolar plate of a hydrogen fuel cell according to claim 6, characterized in that: The outer wall of one side of the elastic strip (44) is in movable contact with the outer wall of the baffle (43), and the interior of the sealing shell (41) is rotatably connected to the upper part of the outer wall of the baffle (43).

8. The porous channel heat dissipation structure adapted to the bipolar plate of a hydrogen fuel cell according to claim 2, characterized in that: An exhaust groove (31) is fixedly connected above one end of the cooling groove (24) near the coolant outlet (21); an outer wall of the exhaust groove (31) is connected through the inside of the bipolar plate body (11); a T-shaped sealing cover (3) is slidably connected inside the exhaust groove (31); an elastic block (32) is fixedly connected to the outer wall of the bottom of the T-shaped sealing cover (3); and an outer wall of the bottom of the elastic block (32) is fixedly connected to the bottom of the inner wall of the exhaust groove (31).

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