Built-in gas cylinder toppling blowout preventer

Abstract

The invention discloses a built-in gas cylinder toppling blowout preventer. Comprising a lower shell and an upper shell, the lower shell and the upper shell are in threaded connection, a neck guiding pipe is arranged at the upper end of the upper shell, a plurality of air inlet channels are formed in the neck guiding pipe in the axial direction, a piston head is arranged in the upper shell, four threaded shafts are all sleeved with reset springs, and a piston rod is arranged in the piston head. The lower end of the reset spring is connected with a piston plate, the four threaded shafts are sleeved with the edge of the piston plate, the piston plate is connected with the piston head through a connecting rod, and the top end of the piston head is located on the lower portions of the air inlet channels under the action of the reset spring. By means of the built-in blowout prevention device, when the gas cylinder topples over, internal high-pressure gas can be prevented from being sprayed out, so that the gas cylinder is prevented from flying up or exploding, and the gas cylinder can be used under the condition of small-angle inclination.

Description

Technical Field

[0001] The present invention belongs to the technical field of pressure vessels, and particularly relates to an in-built anti-blowout device for cylinder tipping. Background Art

[0002] Cylinders are common special equipment and play an important role in various fields. For example, acetylene and oxygen cylinders used for welding and gas cutting, ammonia cylinders in chemical production, and anesthetic cylinders filled with nitrous oxide. However, due to the presence of high-pressure, flammable, and explosive gases inside the cylinders, the safety of cylinders has always been highly concerned. The transportation and use of cylinders are high-incidence periods for dangerous situations. Coupled with improper operation by personnel or the occurrence of sudden events, the occurrence of cylinder accidents is increasing, and the harmfulness is great, easily leading to property damage and even casualties.

[0003] In our actual life, there are many serious accidents caused by the valves at the cylinder mouths falling off due to the cylinders being accidentally tipped over during transportation or handling.

[0004] After the cylinder valve breaks due to falling to the ground, the high-pressure gas inside the cylinder rushes out. The huge pressure difference causes a huge airflow impact, and the huge reaction force of the airflow impact acts on the cylinder, making it ram around randomly at a very high speed, threatening people's lives.

[0005] After the cylinder valve falls off, it will not only generate an impact force but also cause a more serious explosion accident. If the cylinder contains flammable and explosive gases such as acetylene cylinders, after the acetylene cylinder is tipped over, due to the internal pressure and the design of the gas outflow channel, acetylene will flow out quickly. The acetylene cylinder is filled with filler and solvent (acetone), and after tipping over, it will cause the acetone to flow out with the acetylene gas, increasing the consumption of acetone and reducing the combustion temperature, which may cause flashback and explosion.

[0006] During normal use and even transportation, cylinders are placed upright and equipped with special placement racks. For example, the patent application number is CN202321584301.4, and the application name is a movable and splicable anti-tipping rack for cylinders, which ensures that the cylinders remain upright during normal transportation. However, in case of accidents such as car rollovers, the cylinders will still be severely knocked, resulting in the ejection of high-pressure gas inside, driving the cylinders to fly out and easily causing secondary accidents.

[0007] At present, the anti-blowout of cylinder tipping only stays at external anti-blowout prevention, such as equipping upright racks, installing external gas outlet fastening devices and buffer devices, etc., and cannot prevent the gas from spraying out from the inside. These designs can avoid the harm caused by ordinary misoperations and cannot effectively avoid relatively violent movements. Solving the anti-blowout from the inside is an important and feasible solution to solve the safety problems of cylinders.

[0008] In the patent with patent application number CN202321093041.0 and patent application title "An internal gas cylinder tipping anti-spray device", there are a housing, a plurality of first through holes arranged circumferentially on the housing, a second through hole arranged at the bottom of the housing, a movable cavity surrounded by the inner side wall of the housing, a sphere movably arranged in the movable cavity, a plug cover sleeved outside the top end of the housing, an elastic seal located between the plug cover and the housing, a first air passage penetrating through the plug cover, and a second air passage penetrating through the elastic seal. The second through hole and the plurality of first through holes are respectively communicated with the movable cavity; the diameter of the second air passage is smaller than the diameter of the sphere. The plug cover, elastic seal, sphere and housing of the present invention are simple and compact in structure. However, its sensitivity is not high enough and it cannot function at a small inclination angle.

[0009] However, there are some problems in the prior art: When the existing gas cylinders are in use, it is impossible to block the gas cylinders when they are tipped over, which is likely to cause the internal high-pressure gas to spray out, resulting in hazards such as the gas cylinder flying up or exploding, and it cannot be used at a small-angle inclination. Therefore, we propose an internal gas cylinder tipping anti-spray device. Summary of the Invention

[0010] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide an internal gas cylinder tipping anti-spray device. By means of the internal anti-spray device, when the gas cylinder is tipped over, it can prevent the internal high-pressure gas from spraying out, thereby preventing the gas cylinder from flying up or exploding, and it can be used at a small-angle inclination.

[0011] The present invention is implemented as follows. An internal gas cylinder tipping anti-spray device includes a lower housing and an upper housing. The lower housing and the upper housing are threadedly connected. A neck tube is fixedly provided at the upper end of the upper housing. A plurality of air inlets are axially provided on the neck tube. A piston head that is movably located inside the neck tube is provided inside the upper housing. Four through holes are equidistantly arranged on the outer side of the upper housing. Four threaded shafts penetrate through the four through holes. Four return springs are sleeved on the four threaded shafts. The lower ends of the four return springs are connected to a piston plate. The edge of the piston plate is movably sleeved on the four threaded shafts. A connecting rod is fixedly installed in the middle of the piston plate. The top end of the connecting rod is fixedly connected to the bottom end of the piston head. The edge of the piston plate is movably and sealingly connected to the inner wall of the upper housing. The edge of the piston head is movably and sealingly connected to the inner wall of the neck tube. The top end of the piston head is located below the plurality of air inlets under the action of the return spring.

[0012] Furthermore, a first sealing strip is sleeved and installed on the edge of the piston plate, and a second sealing strip is sleeved and installed on the edge of the piston head.

[0013] Further, a connecting threaded post is fixedly provided at the upper end of the lower housing, and a threaded groove is opened inside the lower end of the upper housing. The upper housing and the lower housing are threadedly connected through the connecting threaded post and the threaded groove.

[0014] Further, gasket grooves are opened on the upper end face of the lower housing and the lower end face of the upper housing, and a sealing gasket is snap-fitted inside the gasket grooves.

[0015] Further, a mating threaded post is fixedly provided at the upper end of the necking tube. An air outlet passage communicating with the necking tube is opened inside the mating threaded post, and the inner diameter of the air outlet passage is smaller than the inner diameter of the necking tube.

[0016] Further, a positioning baffle is provided at the upper end of the necking tube. A rubber sleeve is provided on the positioning baffle, and both the positioning baffle and the rubber sleeve are sleeved outside the mating threaded post.

[0017] Further, threaded holes are opened at the upper edge of the upper end of the connecting threaded post. The bottom ends of the four threaded shafts are threadedly connected inside the threaded holes, and the end face of the piston plate fits against the upper end face of the connecting threaded post under the action of the return spring.

[0018] Further, a spherical moving cavity is opened inside the lower housing. A first air passage is opened at the lower part of the lower housing, and a second air passage is opened at the upper part of the lower housing. The first air passage and the second air passage are communicated through the spherical moving cavity, and the second air passage penetrates through the connecting threaded post.

[0019] Further, a sphere is movably installed inside the spherical moving cavity. A cavity is opened at the upper end inside the sphere, and a third air passage communicating axially is opened at the center of the sphere.

[0020] Further, the diameter of the third air passage is the same as the diameters of the first air passage and the second air passage, and the first air passage and the second air passage are on the same axis.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] When the present invention is in use, the piston head is pushed by the high-pressure gas inside the gas cylinder, so that when the gas cylinder is tilted, the high-pressure gas can enter the inside of the upper housing. Under the thrust of the high-pressure gas, the piston plate, the connecting rod and the piston head are pushed upward, so that the piston head can block the air inlet passage on the necking tube, preventing the high-pressure gas from entering the air inlet passage, enabling the anti-spray device to achieve blocking and preventing the high-pressure gas from spraying out, thereby improving the safety of the gas cylinder when it is tilted.

[0023] In order to allow the high-pressure gas to enter the interior of the upper shell body when the gas cylinder is tipped over, the present invention provides an eccentrically weighted sphere inside the lower shell body. When the gas cylinder is in a vertical state, the eccentrically weighted sphere is in a horizontal plane under the action of gravity, and when the gas cylinder is slightly tilted, the third gas passage is not connected with the first gas passage and the second gas passage under the action of gravity, so that the gas cylinder can be used safely. When the gas cylinder is completely tipped over, the heavier part of the sphere is in the lower part under the action of gravity. At this time, the third gas passage is connected with the first gas passage and the second gas passage, so that the high-pressure gas in the gas cylinder enters the upper shell body, pushing the piston plate, pushing the piston plate, the connecting rod and the piston head upward, so that the piston head can block the air inlet on the neck pipe, so that the air inlet cannot enter the high-pressure gas, so that the blowout prevention device can be blocked to prevent the high-pressure gas from spraying out, thereby improving the safety of the gas cylinder when tipping over.

[0024] When the gas cylinder is lifted up, the gas is reset under the action of gravity. At this time, the third air channel is staggered with the first air channel and the second air channel, so that the high-pressure gas no longer enters the interior of the upper shell body, and under the action of the reset spring, the piston plate, the connecting rod and the piston head move downward, and the piston head is separated from the blockage of the air inlet channel on the neck tube, so that the gas cylinder can be used normally.

[0025] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a side view structural schematic diagram provided by the present invention;

[0027] Figure 2 It is a schematic diagram of the structure provided by the present invention when viewed from above;

[0028] Figure 3 is a bottom view schematic diagram of the outer shell provided by the present invention;

[0029] Figure 4 is a schematic top view of the outer shell provided by the present invention;

[0030] Figure 5 It is a top view schematic diagram of the internal structure provided by the present invention;

[0031] Figure 6 It is a bottom view schematic diagram of the internal structure provided by the present invention;

[0032] Figure 7 The figure is a cross-sectional schematic diagram of the explosion structure provided by the present invention.

[0033] In the figure: 1. Lower housing; 2. Upper housing; 3. Necking tube; 4. Air inlet duct; 5. Matching threaded post; 6. First air duct; 7. Spherical movable cavity; 8. Second air duct; 9. Sphere; 10. Cavity; 11. Third air duct; 12. Threaded shaft; 13. Return spring; 14. Piston plate; 15. Connecting rod; 16. Piston head; 17. Sealing gasket; 18. First sealing strip; 19. Second sealing strip; 20. Threaded hole; 21. Through hole; 22. Positioning baffle; 23. Rubber sleeve; 24. Gasket groove; 25. Threaded groove; 26. Connecting threaded post; 27. Air outlet duct. Detailed implementation manner

[0034] In order to further understand the content, features and effects of the present invention, the following embodiments are exemplified and described in detail with reference to the accompanying drawings as follows.

[0035] As Figures 1 to 7 shown, an internal gas cylinder tipping anti-spray device provided by an embodiment of the present invention includes a lower housing 1 and an upper housing 2. The lower housing 1 and the upper housing 2 are threadedly connected. The upper end of the upper housing 2 is fixedly provided with a necking tube 3. A plurality of air inlet ducts 4 are axially opened on the necking tube 3. Inside the upper housing 2, there is a piston head 16 movably located inside the necking tube 3. Four through holes 21 are equidistantly opened on the outer side of the upper housing 2. Four threaded shafts 12 penetrate through the four through holes 21. Return springs 13 are sleeved on the four threaded shafts 12. The lower end of the return spring 13 is connected to a piston plate 14. The edge of the piston plate 14 is movably sleeved on the four threaded shafts 12. A connecting rod 15 is fixedly installed in the middle of the piston plate 14. The top end of the connecting rod 15 is fixedly connected to the bottom end of the piston head 16. The edge of the piston plate 14 is movably and sealingly connected to the inner wall of the upper housing 2. The edge of the piston head 16 is movably and sealingly connected to the inner wall of the necking tube 3. Under the action of the return spring 13, the top end of the piston head 16 is located below a plurality of air inlet ducts 4.

[0036] In this embodiment, preferably, a first sealing strip 18 is sleeved and installed on the edge of the piston plate 14, and a second sealing strip 19 is sleeved and installed on the edge of the piston head 16;

[0037] It should be noted that the setting of the first sealing strip 18 can improve the sealing performance of the piston plate 14 during sliding, and the setting of the second sealing strip 19 can improve the sealing performance of the piston head 16 during sliding, and can improve the stable sliding performance of the piston plate 14 and the piston head 16 during sliding.

[0038] In this embodiment, preferably, a connecting threaded post 26 is fixedly provided at the upper end of the lower housing 1, a threaded groove 25 is opened on the inner side of the lower end of the upper housing 2, and the upper housing 2 and the lower housing 1 are threadedly connected through the connecting threaded post 26 and the threaded groove 25;

[0039] It should be noted that the setting of the connecting threaded column 26 facilitates the threaded connection between the upper housing 2 and the lower housing 1 through the threaded groove 25, improving the stable connection between the lower housing 1 and the upper housing 2.

[0040] In this embodiment, preferably, gasket grooves 24 are provided on the upper end face of the lower housing 1 and the lower end face of the upper housing 2, and a sealing gasket 17 is snap-fitted and installed inside the gasket grooves 24;

[0041] It should be noted that the setting of the gasket grooves 24 facilitates the installation and connection of the sealing gasket 17, thereby maintaining the sealing between the lower housing 1 and the upper housing 2 and improving the contact between the lower housing 1 and the upper housing 2.

[0042] In this embodiment, preferably, a mating threaded column 5 is fixedly provided at the upper end of the neck tube 3, and an air outlet passage 27 communicating with the neck tube 3 is provided inside the mating threaded column 5, and the inner diameter of the air outlet passage 27 is smaller than the inner diameter of the neck tube 3;

[0043] It should be noted that the setting of the mating threaded column 5 facilitates the connection of the blowout preventer to the gas outlet of the gas cylinder, and the diameter of the air outlet passage 27 is smaller than the diameter of the neck tube 3, which can improve the efficiency and rate of gas outlet.

[0044] In this embodiment, preferably, a positioning baffle 22 is provided at the upper end of the neck tube 3, a rubber sleeve 23 is provided on the positioning baffle 22, and both the positioning baffle 22 and the rubber sleeve 23 are sleeved outside the mating threaded column 5;

[0045] It should be noted that the positioning baffle 22 and the rubber sleeve 23 are in direct contact. When the mating threaded column 5 is engaged with the valve air inlet, the positioning baffle 22, the rubber sleeve 23 and the valve base are deformed by extrusion, which can fully achieve the sealing effect and prevent gas leakage.

[0046] In this embodiment, preferably, a threaded hole 20 is provided at the upper edge of the connecting threaded column 26, the bottom ends of the four threaded shafts 12 are threadedly connected in the threaded hole 20, and the end face of the piston plate 14 is in contact with the upper end face of the connecting threaded column 26 under the action of the return spring 13;

[0047] It should be noted that the connection of the bottom ends of the threaded shafts 12 is achieved through the threaded hole 20 on the connecting threaded column 26, which can maintain the stable connection of the threaded shafts 12, and the piston plate 14 is in contact with the upper end face of the connecting threaded column 26, facilitating the pushing of high-pressure gas.

[0048] In this embodiment, preferably, a spherical movable cavity 7 is provided inside the lower housing 1, a first air passage 6 is provided in the lower part of the lower housing 1, a second air passage 8 is provided in the upper part of the lower housing 1, the first air passage 6 is communicated with the second air passage 8 through the spherical movable cavity 7, and the second air passage 8 penetrates through the connecting threaded column 26;

[0049] It should be noted that the setting of the spherical movable cavity 7 facilitates the placement of the sphere 9, and the settings of the first air duct 6 and the second air duct 8, which are communicated with the spherical movable cavity 7, can realize the flow of high-pressure gas and realize the pushing and adjustment of the piston plate 14.

[0050] In this embodiment, preferably, a sphere 9 is movably installed inside the spherical movable cavity 7. A cavity 10 is formed at the upper end inside the sphere 9, and a third air duct 11 communicating with each other is axially formed at the center of the sphere 9;

[0051] It should be noted that the setting of the sphere 9 is used to block the entry of high-pressure gas and control the inflow of high-pressure gas. The formation of the cavity 10 enables the sphere 9 to form an eccentric weight, and under the action of gravity, the angle of the sphere 9 can be adjusted to facilitate the communication between the third air duct 11 and the first air duct 6 and the second air duct 8, realizing the inflow of high-pressure gas.

[0052] In this embodiment, preferably, the diameter of the third air duct 11 is the same as that of the first air duct 6 and the second air duct 8, and the first air duct 6 and the second air duct 8 are on the same axis;

[0053] It should be noted that the same diameter of the third air duct 11 and the first air duct 6 and the second air duct 8 facilitates docking and enables the inflow of high-pressure gas. The first air duct 6 and the second air duct 8 are on the same axis, and the third air duct 11 is axially arranged, facilitating the communication between the first air duct 6 and the second air duct 8 through the third air duct 11 when the sphere 9 rotates.

[0054] The specific operation process of this application:

[0055] When in use, the blowout preventer is connected to the output port of the gas cylinder through the cooperating threaded column 5, and the positioning baffle 22 and the rubber sleeve 23 are directly attached between the blowout preventer and the output port of the gas cylinder. When the cooperating threaded column 5 and the valve air inlet are engaged, the positioning baffle 22, the rubber sleeve 23 and the valve base are deformed by extrusion, which can fully achieve the sealing effect and prevent gas leakage;

[0056] When the gas cylinder is tipped over, the ball 9 in the spherical active cavity 7 inside the lower shell 1 rotates, that is, a cavity 10 is opened at the center of the upper end of the ball 9. The setting of the cavity 10 facilitates the ball 9 to be kept in a state where the angle of the ball 9 can be effectively adjusted when the gas cylinder is tipped over, that is, the center of gravity of the ball 9 is lowered to be lower than the center of its own circle, so that the cavity 10 can be stably located at the upper end of the ball 9, and four third air passages 11 are opened in the transverse direction of the ball 9. If the gas cylinder is placed vertically, the third air passage 11 is misaligned with the first air passage 6 and the second air passage 8. The third air passage 11 is arranged so that the high-pressure gas will not enter the interior of the upper shell 2 at this time, and when the gas cylinder is tilted, the third air passage 11 is also arranged in a staggered manner with the first air passage 6 and the second air passage 8, so that the high-pressure gas will not enter the interior of the upper shell 2. When the gas cylinder is tilted, no matter which direction the gas cylinder is tilted, at this time, the sphere 9 is rotated under the action of the cavity 10, so that the cavity 10 in the sphere 9 faces upward, and at this time, part of the third air passage 11 is connected with the first air passage 6 and the second air passage 8, so that the high-pressure gas in the gas cylinder flows into the interior of the upper shell 2;

[0057] When the high-pressure gas flows into the upper shell 2, the high-pressure gas pushes the piston plate 14, and the piston plate 14 is positioned and slidably installed by the four threaded shafts 12, that is, the installation of the piston plate 14 by the four threaded shafts 12 is convenient to maintain the stability of the piston plate 14 under the push of the high-pressure gas, and prevent the piston plate 14 from being unevenly stressed and tilted, and the piston plate 14 is connected to the piston head 16 by the connecting rod 15. When the piston plate 14 is moved and adjusted, the piston head 16 follows the movement and adjustment through the connecting rod 15, so that the piston head 16 can be moved and adjusted in the neck pipe 3, so that the piston head 16 can block the intake duct 4, so that the intake duct 4 no longer enters the high-pressure gas, and the gas is prevented. When the cylinder is tipped over, high-pressure gas is ejected, and when the cylinder is lifted up, the sphere 9 is straightened again, and the third air passage 11 is misaligned with the first air passage 6 and the second air passage 8. At this time, the high-pressure gas no longer enters the upper shell 2 through the first air passage 6 and the second air passage 8, and then, the piston plate 14 is pushed back to its original position by the return spring 13, and at the same time, the piston head 16 is pushed back. At this time, the piston head 16 moves to the lower part of the air inlet 4, and the air inlet 4 introduces high-pressure airflow again, so that the cylinder can achieve normal exhaust. This effect breaks through the irreversible defect of the cylinder's anti-spray self-closure, so that the anti-spray effect is achieved after tipping over and the normal effect is restored after being straightened and upright.

[0058] 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 built-in gas cylinder tipping prevention device, comprising a lower shell (1) and an upper shell (2), characterized in that: The lower shell (1) and the upper shell (2) are threadedly connected, a neck tube (3) is fixedly provided at the upper end of the upper shell (2), a plurality of air inlet passages (4) are axially provided on the neck tube (3), a piston head (16) is provided inside the upper shell (2) and is movable inside the neck tube (3), four through holes (21) are provided at equal intervals on the outer side of the upper shell (2), four threaded shafts (12) are penetrated in the four through holes (21), a return spring (13) is sleeved on the four threaded shafts (12), and the lower end of the return spring (13) is connected to the piston head (16) A piston plate (14) is provided, the edge of which is movably sleeved on the four threaded shafts (12); a connecting rod (15) is fixedly installed in the middle of the piston plate (14); the top end of the connecting rod (15) is fixedly connected to the bottom end of the piston head (16); the edge of the piston plate (14) is movably sealed to the inner wall of the upper shell (2); the edge of the piston head (16) is movably sealed to the inner wall of the neck tube (3); and the top end of the piston head (16) is located at the bottom of several of the intake ducts (4) under the action of the return spring (13).

2. A built-in gas cylinder tipping prevention device according to claim 1, characterized in that: A first sealing strip (18) is sleeved and installed on the edge of the piston plate (14), and a second sealing strip (19) is sleeved and installed on the edge of the piston head (16).

3. The built-in gas cylinder tipping prevention device according to claim 1, characterized in that: A connecting threaded column (26) is fixedly provided at the upper end of the lower shell (1), a threaded groove (25) is provided on the inner side of the lower end of the upper shell (2), and the upper shell (2) and the lower shell (1) are threadedly connected via the connecting threaded column (26) and the threaded groove (25).

4. The built-in gas cylinder tipping prevention device according to claim 1 is characterized in that: The upper end surface of the lower shell (1) and the lower end surface of the upper shell (2) are both provided with a gasket groove (24), and a sealing gasket (17) is mounted in the gasket groove (24).

5. The built-in gas cylinder tipping prevention device according to claim 1 is characterized in that: A matching threaded column (5) is fixedly provided at the upper end of the neck guide tube (3), and an air outlet (27) communicating with the neck guide tube (3) is provided inside the matching threaded column (5), and the inner diameter of the air outlet (27) is smaller than the inner diameter of the neck guide tube (3).

6. A built-in gas cylinder tipping prevention device according to claim 5, characterized in that: The upper end of the neck guide tube (3) is provided with a positioning baffle (22), and a rubber sleeve (23) is provided on the positioning baffle (22). Both the positioning baffle (22) and the rubber sleeve (23) are sleeved on the outer side of the matching threaded column (5).

7. The built-in gas cylinder tipping prevention device according to claim 3 is characterized by: A threaded hole (20) is provided at the upper edge of the connecting threaded column (26), and the bottom ends of the four threaded shafts (12) are threadedly connected in the threaded hole (20). Under the action of the return spring (13), the end surface of the piston plate (14) is attached to the upper end surface of the connecting threaded column (26).

8. The built-in gas cylinder tipping prevention device according to claim 7, characterized in that: A spherical movable cavity (7) is provided inside the lower shell (1), a first air passage (6) is provided at the lower portion of the lower shell (1), and a second air passage (8) is provided at the upper portion of the lower shell (1); the first air passage (6) and the second air passage (8) are connected via the spherical movable cavity (7), and the second air passage (8) passes through the connecting threaded column (26).

9. The built-in gas cylinder tipping prevention device according to claim 8, characterized in that: A spherical body (9) is movably mounted inside the spherical movable chamber (7), a cavity (10) is provided at the upper end of the interior of the spherical body (9), and a third air passage (11) is provided in communication with the central axis of the spherical body (9).

10. A built-in gas cylinder tipping prevention device according to claim 9, characterized in that: The diameter of the third air channel (11) is the same as the diameters of the first air channel (6) and the second air channel (8), and the first air channel (6) and the second air channel (8) are located on the same axis.

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