An inflatable ring main unit

Abstract

The present invention discloses an inflatable ring network cabinet, including a cabinet, a switch, a one-way inflation valve, a primary condensation cover, a locking mechanism, a pressure plate, an insulation block, a silicone rubber pad, a thermally conductive copper pad, a heating electrode, a secondary condensation cover, a thermally insulating sleeve, an outer sleeve, a sponge block, an inner copper tube, a converging channel, an explosion-proof mechanism, a spherical cap, and a capillary. When started, the heating electrode heats the thermally conductive copper pad, and the heated copper pad quickly transfers heat to the inner copper tube, and the inner copper tube heats the sponge block and activated carbon powder to vaporize the liquid stored therein, and the vaporized gas is ejected along the air jet hole, so that the cabinet is filled with sulfur tetrafluoride gas, ensuring the reliability of the switch operation. The explosion-proof mechanism can release the pressure when the pressure in the cabinet increases sharply, prevent the cabinet from exploding under high pressure, and improve the safety performance. The device has a simple structure, can vaporize sulfur tetrafluoride after condensation, ensure a safe environment in the cabinet, and improve the safety performance. At the same time, an explosion-proof design is adopted to improve the safety performance of the cabinet.

Description

Technical Field

[0001] The invention relates to a ring main unit, in particular to an inflatable ring main unit. Background Art

[0002] The ring main unit is a group of electrical equipment (high-voltage switchgear) installed in a metal or non-metallic insulating cabinet or made into an assembled interval ring main unit. Its core part uses load switches and fuses, which have the advantages of simple structure, small size, low price, improved power supply parameters and performance, and power supply safety. It is widely used in distribution stations and box-type substations in urban residential areas, high-rise buildings, large public buildings, factories and enterprises and other load centers. In order to improve the safety performance of the ring main unit, it is often necessary to fill the cabinet with sulfur tetrafluoride gas. Since sulfur tetrafluoride gas will condense under a certain pressure and low temperature, the concentration of safety gas in the cabinet will be reduced, resulting in reduced safety performance. In view of the above defects, it is necessary to design an inflatable ring main unit. Summary of the invention

[0003] The purpose of the present invention is to provide an inflatable ring main unit, which can vaporize the safety gas after condensation, ensure a safe environment inside the cabinet, improve safety performance, and at the same time, adopt an explosion-proof design to improve the safety performance of the cabinet.

[0004] To solve the above technical problems, the technical scheme of the present invention is: an inflatable ring network cabinet, comprising a cabinet, a switch, and a one-way inflation valve, wherein the switch is installed at the upper inner end of the cabinet, the one-way inflation valve passes through the cabinet, and the one-way inflation valve is threadedly connected to the cabinet, and also comprises a primary condensation hood, a locking mechanism, a pressure plate, an insulation block, a silicone rubber pad, a thermally conductive copper pad, a heating electrode, a secondary condensation hood, an insulation sleeve, an outer sleeve, a sponge block, an inner copper tube, a converging channel, an explosion-proof mechanism, a spherical cap, and a capillary. The primary condensation hood is located at the lower inner end of the cabinet, the primary condensation hood is welded to the cabinet, the locking mechanism is located at the lower outer end of the cabinet, the locking mechanism is welded to the cabinet, the locking mechanism passes through the pressure plate, the insulation block is arranged at the upper end of the pressure plate, the silicone rubber pad is arranged between the insulation block and the cabinet, the thermally conductive copper pad is embedded in the insulation block, the thermally conductive copper pad is connected to the insulation block by interference fit, and one end of the heating electrode passes through the insulation block and is inserted into the insulation block. A hot copper pad, the other end of the heating electrode is connected to the insulation block by bolts, the secondary condensation cover is located inside the cabinet and is sleeved on the bottom of the primary condensation cover, the secondary condensation cover is connected to the cabinet by bolts, the insulation sleeve is embedded in the center of the secondary condensation cover, the outer sleeve is located at the upper end of the insulation sleeve, the outer sleeve is threadedly connected to the insulation sleeve, the sponge block is located inside the insulation sleeve and at the lower end of the outer sleeve, the inner copper tube passes through the outer sleeve, the sponge block, the cabinet, the silicone rubber pad and the insulation block from top to bottom in sequence and is inserted into the thermally conductive copper pad, the inner copper tube is connected to the thermally conductive copper pad by interference fit, the confluence channel is arranged on the inner side of the insulation sleeve, the confluence channel passes through the insulation sleeve, the explosion-proof mechanism passes through the thermally conductive copper pad, the explosion-proof mechanism is threadedly connected to the thermally conductive copper pad, the spherical cap is located at the top of the inner copper tube, the spherical cap is threadedly connected to the inner copper tube, the capillary is located between the outer sleeve and the inner copper tube, and the capillary is bonded to the outer sleeve.

[0005] The present invention is further improved as follows:

[0006] Furthermore, the locking mechanism also includes a welding stud, a marking sleeve, and a hexagonal nut. The welding stud is located at the bottom of the outer side of the cabinet, and the welding stud is welded to the cabinet. The marking sleeve is located on the outer side of the welding stud, and the marking sleeve is threadedly connected to the welding stud. The hexagonal nut is located at the bottom of the marking sleeve, and the hexagonal nut is welded to the marking sleeve. During installation, the marking sleeve is passed through the pressure plate and sleeved on the welding stud. The hexagonal nut is tightened, and the pressure plate is subjected to force to press the insulation block and the silicone rubber pad to the cabinet. Since the length of the marking sleeve is fixed, when the marking sleeve contacts the cabinet, it can be determined that the compression of the silicone rubber is sufficient to form a reliable sealing effect.

[0007] Furthermore, the pressing plate is also provided with a positioning tongue, which is integrally connected to the pressing plate. The positioning tongue is embedded in the thermal conductive copper pad to position it, thereby preventing it from rotating and improving the pressing effect.

[0008] Furthermore, the outer sleeve is also provided with an air jet hole, which is located at the upper end of the outer sleeve and passes through the outer sleeve.

[0009] Furthermore, the outer sleeve is also provided with a sponge sleeve, which is located at the top of the inner side of the outer sleeve and is penetrated by the inner copper tube. The sponge sleeve is bonded to the outer sleeve and is used to be arranged on the top of the capillary to store a certain amount of liquid, and can directly release gas when the inner copper tube is heated.

[0010] Furthermore, the inner copper tube is also provided with a conical air inlet hole, which penetrates the inner copper tube. The conical air inlet hole has a larger aperture near the outer wall of the inner copper tube, which effectively reduces the resistance of gas entering the inner copper tube.

[0011] Furthermore, the explosion-proof mechanism also includes a plug, a first piston, a ventilation pipe, a second piston, a spring, a puncture head, and an explosion-proof membrane. The plug is located at the bottom of the thermally conductive copper pad, the plug is threadedly connected to the thermally conductive copper pad, the first piston is located at the lower end of the inner copper tube, the first piston slides along the upper and lower directions of the inner copper tube, the upper end of the ventilation pipe is welded to the first piston, the lower end of the ventilation pipe is inserted into the plug, the second piston is located at the upper end of the outer side of the ventilation pipe, the second piston is welded to the ventilation pipe, the spring is located between the plug and the second piston and at the outer side of the ventilation pipe, the puncture head is located at the lower end of the ventilation pipe, the puncture head is integrally connected to the ventilation pipe, the explosion-proof membrane is located at the lower end of the plug, and the explosion-proof membrane is adhesively connected to the plug.

[0012] Furthermore, the ventilation pipe is also provided with a first air leakage hole, and the first air leakage hole is located between the first piston and the second piston, and the first air leakage hole runs through the ventilation pipe.

[0013] Furthermore, the ventilation pipe is also provided with a second air leakage hole, which is located at the upper end of the puncture head and runs through the ventilation pipe. When the pressure in the cabinet increases sharply, the high-pressure gas enters the inner copper tube through the conical air inlet hole to push the first piston downward, the spring is compressed, and the ventilation pipe drives the puncture head to move downward quickly to pierce the explosion-proof membrane. The high-pressure gas flows into the ventilation pipe through the first air leakage hole and then is discharged from the cabinet through the second air leakage hole, thereby unloading the pressure in the cabinet to prevent the cabinet from exploding under high pressure. The gas can be replenished in the cabinet through the one-way inflation valve.

[0014] Compared with the prior art, the inflatable ring network cabinet, when working, due to the condensation of liquid, the sulfur tetrafluoride in the cabinet is condensed, and the first-level condensation cover and the second-level condensation cover with a trumpet-shaped cross-section can collect the condensed liquid droplets and flow into the upper end of the insulation sleeve at the lowest point. The liquid flows into the sponge block through the confluence channel. Capillaries are arranged between the inner copper tube and the outer sleeve to form a capillary effect, and the liquid is transported from top to bottom along the inner copper tube; when starting, the heating electrode heats the thermal conductive copper pad, and the heated copper pad quickly transfers heat to the inner copper tube. The inner copper tube heats the sponge block and activated carbon powder to vaporize the stored liquid. The vaporized gas is ejected along the jet hole, so that the cabinet is filled with sulfur tetrafluoride gas, ensuring the reliability of the switch. The insulation sleeve effectively insulates and prevents the heat of the inner copper tube from being transferred to the second-level condensation cover, which affects the convergence of the liquid. The explosion-proof mechanism can release the pressure when the pressure in the cabinet increases sharply, prevent the cabinet from exploding under high pressure, and improve safety performance. The device has a simple structure and can vaporize sulfur tetrafluoride after it is condensed, thereby ensuring a safe environment inside the cabinet and improving safety performance. At the same time, an explosion-proof design is adopted to improve the safety performance of the cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The schematic diagram of the structure of the present invention is shown

[0016] Figure 2 A partial enlarged view of the circle marked with I in the present invention is shown

[0017] Figure 3 A partial enlarged view of the circle marked II of the present invention is shown

[0018] Figure 4 A schematic diagram showing the structure of the locking mechanism of the present invention is shown.

[0019] Figure 5 A three-dimensional diagram of the pressure plate of the present invention is shown.

[0020] Figure 6 The schematic diagram of the explosion-proof mechanism of the present invention is shown

[0021] In the figure: cabinet 1, switch 2, one-way inflation valve 3, primary condensation cover 4, locking mechanism 5, pressure plate 6, insulation block 7, silicone rubber pad 8, thermal conductive copper pad 9, heating electrode 10, secondary condensation cover 11, insulation sleeve 12, outer sleeve 13, sponge block 14, inner copper tube 15, confluence channel 16, explosion-proof mechanism 17, spherical cap 18, capillary 19, welding stud 501, marking sleeve 502, hexagonal nut 503, positioning tongue 601, air jet hole 1301, sponge sleeve 1302, conical air inlet hole 1501, plug 1701, first piston 1702, vent pipe 1703, second piston 1704, spring 1705, puncture head 1706, explosion-proof membrane 1707, first air leakage hole 1708, second air leakage hole 1709. DETAILED DESCRIPTION

[0022] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6As shown, an inflatable ring network cabinet comprises a cabinet 1, a switch 2, and a one-way inflation valve 3. The switch 2 is installed at the upper end of the inner side of the cabinet 1, and the one-way inflation valve 3 passes through the cabinet 2. The one-way inflation valve 3 is threadedly connected to the cabinet 2. It also comprises a primary condensation cover 4, a locking mechanism 5, a pressure plate 6, an insulation block 7, a silicone rubber pad 8, a thermally conductive copper pad 9, a heating electrode 10, a secondary condensation cover 11, an insulation sleeve 12, an outer sleeve 13, a sponge block 14, an inner copper tube 15, a converging channel 16, an explosion-proof mechanism 17, a spherical cap 18, and a capillary 19. The primary condensation cover 4 is located at the lower end of the inner side of the cabinet 1, and the primary condensation cover 4 is welded to the cabinet 1. The locking mechanism 5 is located at the lower end of the outer side of the cabinet 1, and the locking mechanism 5 is connected to the cabinet 1 is connected by welding, the locking mechanism 5 passes through the pressing plate 6, the insulation block 7 is arranged at the upper end of the pressing plate 6, the silicone rubber pad 8 is arranged between the insulation block 7 and the cabinet 1, the heat-conducting copper pad 9 is embedded in the insulation block 7, and the heat-conducting copper pad 9 is connected to the insulation block 7 by interference fit, one end of the heating electrode 10 passes through the insulation block 7 and is inserted into the heat-conducting copper pad 9, and the other end of the heating electrode 10 is connected to the insulation block 7 by bolts, the secondary condensation cover 11 is located on the inner side of the cabinet 1 and is sleeved on the bottom of the primary condensation cover 4, the secondary condensation cover 11 is connected to the cabinet 1 by bolts, the insulation sleeve 12 is embedded in the center of the secondary condensation cover 11, the outer sleeve 13 is located at the upper end of the insulation sleeve 12, and the outer sleeve 13 is connected to the insulation sleeve 1 2 is connected by thread, the sponge block 14 is located on the inner side of the thermal insulation sleeve 12 and on the lower end of the outer sleeve 13, the inner copper tube 15 passes through the outer sleeve 13, the sponge block 14, the cabinet 1, the silicone rubber pad 8 and the thermal insulation block 7 from top to bottom in sequence and is inserted into the thermally conductive copper pad 9, the inner copper tube 15 is connected to the thermally conductive copper pad 9 by interference fit, the confluence channel 16 is arranged on the inner side of the thermal insulation sleeve 12, the confluence channel 16 passes through the thermal insulation sleeve 12, the explosion-proof mechanism 17 passes through the thermally conductive copper pad 9, the explosion-proof mechanism 17 is threadedly connected to the thermally conductive copper pad 9, the spherical cap 18 is located on the top of the inner copper tube 15, the spherical cap 18 is threadedly connected to the inner copper tube 15, the capillary 19 is located between the outer sleeve 13 and the inner copper tube 15, the capillary 19 is bonded and connected to the outer sleeve 13, and the locking mechanism 5 also includes a welding stud 501, a marking sleeve 502, and a hexagonal nut 503. The welding stud 501 is located at the bottom of the outer side of the cabinet 1, and the welding stud 501 is welded to the cabinet 1. The marking sleeve 502 is located on the outer side of the welding stud 501, and the marking sleeve 502 is threadedly connected to the welding stud 501. The hexagonal nut 503 is located at the bottom of the marking sleeve 502, and the hexagonal nut 503 is welded to the marking sleeve 502. During installation, the marking sleeve 502 is passed through the pressure plate 6 and is sleeved on the welding stud 501. The hexagonal nut 503 is tightened, and the pressure plate 6 is subjected to force to press the insulation block 7 and the silicone rubber pad 8 to the cabinet 1. Since the length of the marking sleeve 502 is fixed,When the marking sleeve 502 contacts the cabinet, it can be determined that the compression amount of the silicone rubber pad 8 is sufficient to form a reliable sealing effect. The pressure plate 6 is also provided with a positioning tongue 601, and the positioning tongue 601 is integrally connected to the pressure plate 6. The positioning tongue 601 is embedded in the thermal conductive copper pad 9 to position it to prevent it from rotating and improve the clamping effect. The outer sleeve 13 is also provided with an air jet hole 1301, and the air jet hole 1301 is located at the upper end of the outer sleeve 13. The air jet hole 1301 penetrates the outer sleeve 13. The outer sleeve 13 is also provided with a sponge sleeve 1302, and the sponge sleeve 1302 is located at the inner top of the outer sleeve 13 and is penetrated by the inner copper tube 15. The sponge sleeve 1302 is bonded to the outer sleeve 13, and the sponge sleeve 13 02 is used to be arranged on the top of the capillary 19, for storing a certain amount of liquid, and can directly release gas when the inner copper tube 15 is heated. The inner copper tube 15 is also provided with a conical air inlet hole 1501, and the conical air inlet hole 1501 runs through the inner copper tube. The aperture of the conical air inlet hole 1501 near the outer wall of the inner copper tube 15 is larger, which effectively reduces the resistance of gas entering the inner copper tube 15. The explosion-proof mechanism 17 also includes a plug 1701, a first piston 1702, a vent 1703, a second piston 1704, a spring 1705, a piercing head 1706, and an explosion-proof membrane 1707. The plug 1701 is located at the bottom of the thermally conductive copper pad 9, and the plug 1701 is threadedly connected to the thermally conductive copper pad 9. The first piston 1702 Located at the lower end of the inner copper tube 15, the first piston 1702 slides along the upper and lower directions of the inner copper tube 15, and a sealing structure such as a sealing ring is provided between the first piston 1702 and the inner copper tube 15 to prevent gas leakage. The upper end of the vent pipe 1703 is welded to the first piston 1702, and the lower end of the vent pipe 1703 is inserted into the plug 1701. The second piston 1704 is located at the upper end of the outer side of the vent pipe 1703, and the second piston 1704 is welded to the vent pipe 1703. The spring 1705 is located between the plug 1701 and the second piston 1704 and is located on the outer side of the vent pipe 1703. The puncture head 1706 is located at the lower end of the vent pipe 1703, and the puncture head 1706 is connected to the vent pipe 17 03 are connected as one body, the explosion-proof membrane 1707 is located at the lower end of the plug 1701, the explosion-proof membrane 1707 is bonded to the plug 1701, the ventilation pipe 1703 is also provided with a first air leakage hole 1708, the first air leakage hole 1708 is located between the first piston 1702 and the second piston 1704, the first air leakage hole 1708 runs through the ventilation pipe 1703, the ventilation pipe 1703 is also provided with a second air leakage hole 1709, the second air leakage hole 1709 is located at the upper end of the piercing head 1706, the second air leakage hole 1709 runs through the ventilation pipe, the diameter of the first piston 1702 is smaller than the diameter of the second piston 1704, so that the gas can smoothly enter the first air leakage hole 1708 through the inner copper tube 15. When the pressure in the cabinet 1 increases sharply,The high-pressure gas enters the inner copper tube 15 through the conical air inlet hole 1501 to push the first piston 1702 downward, the spring 1705 is compressed, and the ventilation pipe 1703 drives the piercing head 1706 to move downward quickly to pierce the explosion-proof membrane 1707. The high-pressure gas flows into the ventilation pipe 1703 through the first air leakage hole 1708 and is discharged from the cabinet 1 through the second air leakage hole 1709, thereby relieving the pressure in the cabinet 1 to prevent the cabinet 1 from exploding under high pressure. The gas can be firstly replenished in the cabinet through the one-way inflation valve 3. When the inflatable ring main unit is working, the sulfur tetrafluoride in the cabinet 1 is condensed due to the condensation of the liquid. The first-level condensation cover 4 and the second-level condensation cover 11 with a trumpet-shaped cross-section can collect the condensed liquid droplets and flow into the upper end of the insulation sleeve 12 at the lowest point. The liquid flows into the sponge block 14 through the confluence channel 16. The capillary 19 is arranged between the inner copper tube 15 and the outer sleeve 13 to form a capillary effect, and the liquid is transported from top to bottom along the inner copper tube 15. When starting, the heating electrode 10 heats the heat-conducting copper pad 9, and the heating copper pad 9 quickly transfers the heat to the inner copper tube 15. The inner copper tube 15 heats the sponge block 14 and the activated carbon powder to vaporize the stored liquid. The vaporized gas is ejected along the jet hole 1301, so that the cabinet 1 is filled with sulfur tetrafluoride gas, ensuring the reliable operation of the switch 2. The insulation sleeve 12 effectively insulates and prevents the heat of the inner copper tube 15 from being transferred to the second-level condensation cover 11, which affects the confluence of the liquid. The explosion-proof mechanism 17 can release the pressure when the pressure in the cabinet 1 increases sharply, preventing the cabinet 1 from exploding under high pressure and improving safety performance. The device has a simple structure and can vaporize sulfur tetrafluoride after condensation, ensuring a safe environment in the cabinet and improving safety performance. At the same time, the explosion-proof design is adopted to improve the safety performance of the cabinet.

[0023] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. An inflatable ring main unit, comprising a cabinet, a switch, and a one-way inflatable valve, wherein the switch is mounted on the upper inner side of the cabinet, the one-way inflatable valve penetrates the cabinet, and the one-way inflatable valve is threadedly connected to the cabinet, characterized in that It also includes a primary condensation hood, a locking mechanism, a pressure plate, an insulation block, a silicone rubber pad, a thermally conductive copper pad, a heating electrode, a secondary condensation hood, an insulation sleeve, an outer sleeve, a sponge block, an inner copper tube, a confluence channel, an explosion-proof mechanism, a spherical cap, and a capillary. The primary condensation hood is located at the lower end of the inner side of the cabinet, the primary condensation hood is welded to the cabinet, the locking mechanism is located at the lower end of the outer side of the cabinet, the locking mechanism is welded to the cabinet, the locking mechanism passes through the pressure plate, the insulation block is arranged at the upper end of the pressure plate, the silicone rubber pad is arranged between the insulation block and the cabinet, the thermally conductive copper pad is embedded in the insulation block, the thermally conductive copper pad is connected to the insulation block by interference fit, one end of the heating electrode passes through the insulation block and is inserted into the thermally conductive copper pad, the other end of the heating electrode is connected to the insulation block by bolts, the secondary condensation hood is located inside the cabinet and is sleeved on the bottom of the primary condensation hood, the secondary condensation hood is connected to the cabinet by bolts, and the insulation sleeve is embedded in the center of the secondary condensation hood. The outer sleeve is located at the upper end of the thermal insulation sleeve, the outer sleeve is threadedly connected to the thermal insulation sleeve, the sponge block is located inside the thermal insulation sleeve and at the lower end of the outer sleeve, the inner copper tube passes through the outer sleeve, the sponge block, the cabinet, the silicone rubber pad and the thermal insulation block from top to bottom in sequence and is inserted into the thermally conductive copper pad, the inner copper tube is connected to the thermally conductive copper pad by interference fit, the confluence channel is arranged on the inner side of the thermal insulation sleeve, the confluence channel passes through the thermal insulation sleeve, the explosion-proof mechanism passes through the thermally conductive copper pad, the explosion-proof mechanism is threadedly connected to the thermally conductive copper pad, the spherical cap is located at the top of the inner copper tube, the spherical cap is threadedly connected to the inner copper tube, the capillary is located between the outer sleeve and the inner copper tube, the capillary is bonded to the outer sleeve, the outer sleeve is also provided with an air jet hole, the air jet hole is located at the upper end of the outer sleeve, the air jet hole passes through the outer sleeve, the outer sleeve is also provided with a sponge sleeve, the sponge sleeve is located at the top of the inner side of the outer sleeve and is penetrated by the inner copper tube, and the sponge sleeve is bonded to the outer sleeve.

2. The inflatable ring main unit according to claim 1, characterized in that The locking mechanism also includes a welding stud, a marking sleeve, and a hexagonal nut. The welding stud is located at the bottom of the outer side of the cabinet, and the welding stud is welded to the cabinet. The marking sleeve is located at the outer side of the welding stud, and the marking sleeve is threadedly connected to the welding stud. The hexagonal nut is located at the bottom of the marking sleeve, and the hexagonal nut is welded to the marking sleeve.

3. The inflatable ring main unit according to claim 1, characterized in that The pressing plate is also provided with a positioning tongue, and the positioning tongue is integrally connected with the pressing plate.

4. The inflatable ring main unit according to claim 1, characterized in that The inner copper tube is also provided with a tapered air inlet hole, and the tapered air inlet hole runs through the inner copper tube.

5. The inflatable ring main unit according to claim 1, characterized in that The explosion-proof mechanism also includes a plug, a first piston, a ventilation pipe, a second piston, a spring, a puncture head, and an explosion-proof membrane. The plug is located at the bottom of the thermally conductive copper pad, and the plug is threadedly connected to the thermally conductive copper pad. The first piston is located at the lower end of the inner copper tube, and the first piston slides along the upper and lower directions of the inner copper tube. The upper end of the ventilation pipe is welded to the first piston, and the lower end of the ventilation pipe is inserted into the plug. The second piston is located at the upper end of the outer side of the ventilation pipe, and the second piston is welded to the ventilation pipe. The spring is located between the plug and the second piston and is located on the outer side of the ventilation pipe. The puncture head is located at the lower end of the ventilation pipe, and the puncture head is integrally connected to the ventilation pipe. The explosion-proof membrane is located at the lower end of the plug, and the explosion-proof membrane is adhesively connected to the plug.

6. The inflatable ring main unit according to claim 5, characterized in that The ventilation pipe is also provided with a first air leakage hole, the first air leakage hole is located between the first piston and the second piston, and the first air leakage hole runs through the ventilation pipe.

7. The inflatable ring main unit according to claim 5, characterized in that The ventilation pipe is also provided with a second air leakage hole, which is located at the upper end of the puncture head and runs through the ventilation pipe.

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