Multi-axis collaborative stirring reaction kettle for electronic-grade chemical production

Abstract

The application discloses a multi-shaft cooperative stirring reaction kettle for electronic-grade chemical production, relates to the technical field of reaction kettles, and is based on a driving assembly, a kettle body and a vertically arranged stirring shaft. A plurality of single-section stirring groups containing single-section air arms and arc-shaped direction limiting frames are linearly arranged along the axial direction and are distributed in a circumferential annular staggered manner on the stirring shaft. The single-section air arms are connected with the stirring shaft through direction limiting connecting pieces and can be slightly deflected in a vertical plane along the direction limiting grooves of the arc-shaped direction limiting frames. Pressure sensing balloon pieces are arranged at the end of the single-section air arms, dynamic direction limiting rotating sleeves and open flaps are arranged on the pressure sensing balloon pieces, multi-shaft cooperative stirring is realized through single-shaft driving, the material working condition can be adaptively matched, mixed dead zones can be effectively eliminated, vortex gas can be inhibited, the temperature and shear strength in the kettle can be balanced, and the purity, uniformity and batch stability of electronic-grade chemical production can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of reactor technology, and more specifically to a multi-axis cooperative stirring reactor for the production of electronic-grade chemicals. Background Technology

[0002] For reaction vessels used in chemical production, firstly, they must meet design conditions such as high pressure and high temperature; secondly, they must possess the physical property of corrosion resistance; and thirdly, they must be equipped with stirring structures to improve reaction efficiency and promote the full reaction of various components. For the reaction process of electronic-grade chemicals, the following requirements exist due to the need for a more refined reaction process: Conventional single-shaft mixing methods have problems such as mixing dead zones (local material does not flow), local overheating, and local differences in shear strength due to the material flow pattern. In particular, during the mixing process, the surface of the mixing liquid generates microbubbles due to the vortex entrainment of air. Taking electronic product coatings containing microbubbles as an example, the process of using them as electronic product coatings may result in coating defects, uneven etching, or even short circuits. Furthermore, the issue of local dead zones can lead to several problems. First, the materials in these areas may not be fully mixed, resulting in significant differences in their reaction rates compared to other areas. Dead zones can also cause localized enrichment / depletion of additives, uneven reaction conversion rates, and batch-to-batch fluctuations in product purity, impurity distribution, and molecular weight distribution. Second, dead zones can cause regional temperature differences, which can reach 5-10°C. Since electronic-grade materials are highly sensitive to temperature during reaction, local overheating can trigger side reactions, material decomposition, impurity generation, and metal ion dissolution. Local undercooling can cause reaction stagnation and uneven crystallization, directly damaging product purity and performance.

[0003] In response to these problems, the present invention proposes a solution. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-axis collaborative stirring reactor for the production of electronic-grade chemicals. Due to the need for precision in the reaction process of electronic-grade materials, conventional single-axis stirring methods often cause problems such as local mixing dead zones, local overheating, and local differences in shear strength, which affect the overall material reaction process and subsequent use.

[0005] The objective of this invention can be achieved through the following technical solution: a multi-axis collaborative stirring reactor for the production of electronic-grade chemicals, comprising a drive assembly, a reactor body and a stirring shaft, wherein the stirring shaft is arranged in a vertical direction and is rotatably connected to the reactor body through the drive assembly; The stirring shaft is provided with multiple single-section stirring groups, including single-section air arms and arc-shaped directional frames, on the outer wall inside the vessel. The single-section stirring groups are arranged in a linear array along the length of the stirring shaft and are arranged in a ring-shaped staggered distribution along the center point of the stirring shaft. One end of the single-stage air arm is connected to the stirring shaft by a directional connector, and the directional connector and the arc-shaped directional frame maintain a small deflection along the vertical plane. An air port sleeve is provided at the upper end of the stirring shaft.

[0006] The further configuration is as follows: the directional connector is fixedly connected to the stirring shaft, and the directional connector is a hemispherical sleeve structure.

[0007] The configuration is further defined as follows: the arc-shaped directional frame is vertically connected to the stirring shaft, and the position of the arc-shaped directional frame corresponds to that of the single air-throttling arm. The center point of the arc-shaped directional frame and the center point of the directional connecting piece are on the same axis.

[0008] The configuration is further defined as follows: the arc-shaped directional frame has a vertically arranged directional groove, and the width of the directional groove is equal to the outer diameter of the single throttle arm.

[0009] A further configuration is provided: a pressure-sensing balloon is installed at the other end of the single throttle arm, the pressure-sensing balloon is provided with a heat-resistant rubber pad on the outside, and the inside of the pressure-sensing balloon is in communication with the inside of the single throttle arm.

[0010] The pressure-sensing balloon is further configured such that the linear distance between the pressure-sensing balloon and the directional connector is equal to or less than the linear distance between the inner wall of the vessel and the outer wall of the stirring shaft, and the pressure-sensing balloon is oriented at an inclination along the horizontal plane.

[0011] The configuration is further defined as follows: the arc-shaped directional frame is oriented and inclined along the horizontal plane, and the inclination direction of the arc-shaped directional frame is related to the rotation direction of the stirring shaft and the inclination direction of the pressure-sensing bladder; the length direction of the single air-saving arm and the slotting direction of the directional groove are parallel to the diameter direction of the vessel body.

[0012] The configuration is further defined as follows: a dynamic directional sleeve is slidably installed on the outer wall position between the pressure-sensing balloon and the arc-shaped directional frame of the single throttle arm, and an open wing is provided on the outer wall position between the arc-shaped directional frame and the directional connector and on the outer wall position of the dynamic directional sleeve of the single throttle arm.

[0013] Further configuration: a steering limiting structure is provided between the dynamic directional control sleeve and the single throttle arm, and the curvature and thickness distribution of each open wing are different.

[0014] The present invention has the following beneficial effects: This invention utilizes a single stirring shaft to mount multiple axially arrayed, circumferentially staggered single-section stirring units, forming a multi-axis stirring structure distinct from single-axis methods. This single-axis drive achieves a multi-axis synergistic, all-dimensional stirring effect, breaking the fixed flow field of conventional single-axis stirring and eliminating mixing dead zones in areas such as near the vessel wall, bottom corners, and below the liquid surface. Furthermore, the directional, tilted arc-shaped directional frame and single-section air arm guide the material to form a three-dimensional circulating flow field, effectively suppressing the formation of surface vortices and preventing the incorporation of microbubbles into the material due to vortex entrainment. This mitigates quality risks such as coating defects and short circuits in subsequent applications of electronic-grade chemicals. Simultaneously, a pressure-sensitive balloon component senses real-time changes in the material's rheological properties, causing the single-section air arm to adaptively adjust its stirring radius. Combined with differentiated open blades, this generates multi-dimensional turbulent disturbances, balancing the shear intensity in different regions of the vessel and controlling local temperature differences to a minimum. This avoids side reactions and impurity generation caused by local overheating and reaction stagnation and uneven crystallization caused by local overcooling, significantly improving the uniformity of electronic-grade chemical reactions, product purity, and batch stability.

[0015] In addition to the above, it should be noted that multi-axis coordinated stirring can be achieved using only a single drive assembly and a single stirring shaft. Compared to conventional multi-drive multi-shaft stirring equipment, this significantly simplifies the overall structure of the equipment, reduces dynamic sealing points, and significantly lowers the risk of media leakage and external impurity intrusion under high-pressure reaction conditions, thereby improving the safety and stability of equipment operation. At the same time, the internal air pressure of the single-section air arm and the pressure-sensing balloon can be flexibly adjusted through the air port sleeve at the upper end of the stirring shaft. Combined with the adaptive sliding and deflection of the dynamic limiting rotating sleeve caused by fluid impact, secondary dynamic adjustment of stirring parameters can be achieved, which can quickly adapt to the production needs of electronic-grade chemicals with different viscosities, different reaction stages, and different operating conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a multi-axis cooperative stirring reactor for the production of electronic-grade chemicals proposed in this invention; Figure 2 This is a cross-sectional view of the vessel body in this invention; Figure 3 For the present invention Figure 2 The front view; Figure 4 This is a top-view schematic diagram of the stirring shaft in this invention; Figure 5 This is a schematic diagram of the arc-shaped directional frame and the single throttle arm in this invention; Figure 6 For the present invention Figure 5 Cross-sectional view of the single throttle arm.

[0018] In the figure: 1. Drive assembly; 2. Vessel body; 3. Air port sleeve; 4. Stirring shaft; 5. Pressure-sensing balloon; 6. Arc-shaped directional frame; 7. Directional groove; 8. Dynamic directional rotating sleeve; 9. Single-stage air arm; 10. Directional connector; 11. Open vane. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: The reaction vessel for the production of electronic-grade chemicals addressed in this example follows the basic principle of conventional technical solutions: a single vertically positioned stirring shaft is rotated by a drive mechanism, and multiple layers of stirring blades are fixedly installed on the stirring shaft. The shearing and thrust generated by the circumferential rotation of the blades propels the material flow within the vessel, achieving mixing, mass transfer, and heat transfer of multiple components. This meets the basic requirements of reaction processes such as the synthesis, compounding, and purification of electronic-grade chemicals. However, the following problems exist in the specific process: In the single-shaft fixed-blade stirring mode, the material flow trajectory is fixed and singular, which easily forms a mixing dead zone in the near-wall area of ​​the inner wall of the vessel, the corner of the bottom of the vessel, and below the liquid surface. This causes uneven mixing of materials, local enrichment or depletion of additives, which directly leads to large fluctuations in product purity, impurity content, and molecular weight distribution between batches. At the same time, the shear strength of the fixed blades is severely unevenly distributed radially. Excessive shearing in some areas can easily cause material decomposition and side reactions, while insufficient shearing will cause the reaction to stagnate. Moreover, the high-speed rotating blades can easily drive the liquid surface to form vortices and generate air entrapment. Tiny air bubbles mixed in the material can cause pinholes and defects in the subsequent electronic coating, and even cause serious quality accidents such as uneven etching and short circuits. Furthermore, the presence of mixing dead zones and stagnant layers can lead to local temperature differences of 5-10°C within the reactor. Since the reaction process of electronic-grade chemicals is extremely sensitive to temperature, local overheating can cause material decomposition, impurity generation, and metal ion dissolution, while local undercooling can lead to reaction stagnation and uneven crystallization, severely damaging product performance and yield. To address this, the present invention proposes the following technical solution: Reference Figures 1-6This embodiment provides a multi-axis collaborative stirring reactor for the production of electronic-grade chemicals, including a drive assembly 1, a reactor body 2, and a stirring shaft 4 arranged vertically. The stirring shaft 4 is rotatably connected to the reactor body 2 through the drive assembly 1. The stirring shaft 4 is provided with multiple sets of single-section stirring groups on the outer wall inside the reactor body 2. Each set of single-section stirring groups includes a single-section gas arm 9 and an arc-shaped directional frame 6. The multiple sets of single-section stirring groups are linearly arrayed along the length of the stirring shaft 4 and are arranged in a ring-shaped staggered distribution along the center point of the stirring shaft 4. One end of the single-section gas arm 9 is connected to the stirring shaft 4 through a directional connector 10, and can be kept in a small-amplitude deflection state along the vertical plane through the directional connector 10 and the arc-shaped directional frame 6. An air port sleeve 3 communicating with the inside of the single-section gas arm 9 is provided at the upper end of the stirring shaft 4. This solution uses a single main shaft to drive multiple sets of adaptively deflectable stirring units, achieving a multi-axis coordinated stirring effect. It breaks the fixed flow field of conventional single-axis stirring, eliminates mixing dead zones at the source, suppresses vortex entrainment, balances shear strength, and reduces local temperature differences. It is fully adapted to the high purity, high uniformity, and high stability requirements of electronic-grade chemical production, and the driving method can be belt drive.

[0021] Example 2: This example is described in detail below with reference to relevant technical features: When the reactor starts up, the drive component 1 outputs torque, which drives the stirring shaft 4 to rotate at a constant speed along the preset rotation direction. The stirring shaft 4 synchronously drives all the single-section stirring groups fixed to its outer wall to make synchronous circumferential motion, realizing the basic stirring action. In each single-section stirring group, the hemispherical sleeve structure limiting connector 10 is fixedly connected to the stirring shaft 4, providing a stable deflection fulcrum for the single-section air arm 9. The arc-shaped limiting frame 6 is vertically fixedly connected to the stirring shaft 4. Its setting position corresponds one-to-one with the single-section air arm 9, and the center point of the arc-shaped limiting frame 6 and the center point of the limiting connector 10 are on the same axis. The single-section air arm 9 passes through the vertically opened limiting groove 7 inside the arc-shaped limiting frame 6. The groove width of the limiting groove 7 is equal to the outer diameter of the single-section air arm 9, which not only provides precise guidance and limit for the vertical plane deflection of the single-section air arm 9, avoiding the deviation of the circumferential deflection trajectory, but also prevents the single-section air arm 9 from radial movement during high-speed rotation, ensuring the stability and consistency of the stirring trajectory. As the stirring shaft 4 continues to rotate, the pressure-sensing balloon 5 installed at the end of the single-stage air arm 9 moves in a circular motion synchronously with the single-stage air arm 9. The interior of the pressure-sensing balloon 5 is connected to the internal air passage of the single-stage air arm 9. The internal air pressure can be precisely adjusted through the air port sleeve 3 at the upper end of the stirring shaft 4 to adapt to the stirring needs of materials with different viscosities and working conditions. Stable gas can also be filled into the single-stage air arm 9. The pressure change in the pressure-sensing balloon 5 can be obtained in real time during the specific operation process, thereby indirectly reflecting the relative state of material stirring in a single area. The pressure-sensitive balloon 5 is covered with a heat-resistant rubber pad, which can directly act on the material in the near-wall area of ​​the inner wall of the vessel 2 during rotation, breaking the stagnant layer in the near-wall area and eliminating the mixing dead zone that is very easy to occur in the near-wall area in conventional stirring schemes. To this end, it is also necessary to further limit the overall length of the single air-blocking arm 9 to ensure that the material in the entire radial area inside the vessel can be fully mixed. Simultaneously, the pressure-sensing bulb 5 can sense changes in material viscosity and fluid pressure at different radial positions during rotation in real time. When the viscosity of the material inside the vessel increases or the local material state changes, the pressure-sensing bulb 5 will generate corresponding deformation, thereby driving the single-stage air arm 9 to make a small-amplitude deflection in the vertical plane along the limiting groove 7 of the arc-shaped limiting frame 6, realizing adaptive dynamic adjustment of the stirring radius. Specifically, under normal conditions, each single-stage air arm 9 naturally hangs down to the lowest point of the limiting groove 7 under the action of gravity. However, when it rotates, on the one hand, due to the buoyancy and reaction force of the raw material, and on the other hand, due to the small-amplitude centrifugal force generated during rotation, it can automatically match the optimal stirring coverage and stirring intensity according to the real-time changes in the rheological characteristics of the material, avoiding the problems of uneven mixing and insufficient reaction caused by the fixed blades not being able to adapt to changes in the material state. Figure 3 Taking the uppermost single-section mixing group as an example, its mixing area corresponds to the maximum arc area in the arc-shaped directional frame 6; Both the arc-shaped directional frame 6 and the pressure-sensing spherical element 5 are oriented and inclined along the horizontal plane. The inclination direction of the arc-shaped directional frame 6 is related to the rotation direction of the stirring shaft 4 and the inclination direction of the pressure-sensing spherical element 5. The length direction of the single-throttling arm 9 and the slotting direction of the directional groove 7 are parallel to the diameter direction of the vessel body 2. During the rotational stirring process, this inclined structure can generate a combined radial and axial thrust on the material simultaneously, breaking the limitation of conventional single-axis stirring which can only form a planar circular flow field. For example, in conventional stirring methods, which are single-axis unidirectional rotation methods, vortices are inevitably generated. Under the action of centrifugal force, the raw materials produce obvious stratification, such as light on top and heavy on the bottom, dense in the central area and loose in the outer area. This guides the material to form a three-dimensional flow field with up and down circulation inside the reactor body 2, effectively suppressing the formation of liquid surface vortices during stirring. This avoids the problem of tiny bubbles mixed into the material caused by vortex air entrainment, and greatly reduces the risk of coating defects, uneven etching, and short circuits when electronic-grade chemicals are subsequently used as electronic coatings, etching solutions, and other products. For stirring processes with special requirements, the pressure inside the reactor body can also be increased to promote the overflow and breakage of bubbles in the raw materials. Meanwhile, the three-dimensional flow field can significantly enhance the mass and heat transfer efficiency of materials in the reactor, quickly balance the temperature of each area in the reactor, control the local temperature difference within a very small range, avoid side reactions, material decomposition, impurity generation and metal ion dissolution caused by local overheating, and eliminate reaction stagnation and uneven crystallization caused by local overcooling, thus ensuring the purity and performance stability of the product batch. A dynamic directional sleeve 8 is slidably installed on the outer wall of the single throttle arm 9, corresponding to the position between the pressure-sensing balloon 5 and the arc-shaped directional frame 6. Open blades 11 are provided on both the outer wall of the single throttle arm 9, corresponding to the position between the arc-shaped directional frame 6 and the directional connector 10, and on the outer wall of the dynamic directional sleeve 8. A steering limiting structure is provided between the dynamic directional sleeve 8 and the single throttle arm 9. During the stirring process, the dynamic directional sleeve 8 can rotate synchronously with the single throttle arm 9 in the circumferential direction without relative circumferential rotation. Simultaneously, the fluid impact force of the material on the open blades 11 will cause the dynamic directional sleeve 8 to rotate accordingly. A rotation process is formed relative to the axis of the single air arm 9, but its rotation angle is not a full rotation, but rather a combination of the impact force of the raw material fluid on the open vane 11. This requires the use of the directional limiting structure. In addition, the single air arm 9 is deflected up and down and is also impacted by the original fluid, which simultaneously drives the dynamic directional limiting sleeve 8 to slide adaptively along the axis of the single air arm 9. During the sliding process, the effective cantilever length of the single air arm 9 can be changed, thereby realizing the secondary adaptive adjustment of the stirring radius and stirring intensity. This works in synergy with the deflection adjustment of the pressure-sensing balloon 5 to further improve the adaptability of the stirring parameters to changes in material working conditions. To address this, it is necessary to limit the curvature and thickness distribution of each open blade 11 to be different. During rotation, this can generate turbulent disturbances of different intensities and directions on the material, further breaking the laminar flow state of the material, enhancing the micro-mixing effect of the material, and balancing the shear intensity of each region in the reactor to avoid local over-shearing or under-shearing. This ensures that the reaction degree of the material in each region of the reactor is highly consistent, accurately controlling the molecular weight distribution and impurity content of the product, and meeting the high-precision production requirements of electronic-grade chemicals. Multiple sets of single-section stirring groups, linearly arrayed along the length of the stirring shaft 4 and circumferentially staggered, form a multi-axis collaborative, all-dimensional stirring system during rotation. The single-section air arms 9 at different axial positions can fully cover and stir material layers at different heights within the vessel body 2, eliminating axial stirring blind spots. The single-section stirring groups at different circumferential positions form staggered stirring trajectories, further avoiding mixing dead zones. Simultaneously, the independent deflection of each set of single-section air arms 9 creates an asymmetric dynamic flow field, significantly enhancing the mixing effect. It should be noted that this is because the single-section air arms 9 need to be connected to… With the corresponding flexible air tube, the overall stirring structure does not need to perform a continuous unidirectional rotation process, but rather a cyclical rotation process. The single rotation angle is related to the number of single stirring groups. The overall diagram of this invention only includes four single stirring groups, but the number can be changed according to the actual situation. For example, with 6 single stirring groups, each single stirring group is staggered along the ring array, with equal vertical spacing and a ring angle deviation of 60°. The single rotation angle is about 120°. For example, after rotating 120° clockwise, it rotates 240° in the opposite direction, and so on in a cyclical manner.

[0022] Compared to conventional multi-drive multi-shaft stirred reactors, this solution achieves multi-shaft coordinated stirring effect with only a single stirring shaft 4, greatly simplifying the equipment structure, reducing dynamic sealing points, lowering the risk of sealing leakage under high-pressure reaction conditions, and improving the safety and stability of equipment operation. It is perfectly suited to the high-pressure, high-cleanliness, and high-stability requirements of electronic-grade chemical production.

[0023] The above are merely examples and descriptions of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A multi-shaft cooperative stirred reactor for the production of electronic-grade chemicals, comprising a drive assembly (1), a reactor body (2), and a stirring shaft (4), characterized in that, The stirring shaft (4) is arranged in a vertical direction and is rotatably connected to the vessel body (2) through the drive assembly (1); The stirring shaft (4) is provided with multiple single-section stirring groups, including single-section air arms (9) and arc-shaped directional frames (6), on the outer wall inside the vessel body (2). The single-section stirring groups are arranged in a linear array along the length of the stirring shaft (4) and are arranged in a ring-shaped staggered distribution along the center point of the stirring shaft (4). One end of the single air arm (9) is connected to the stirring shaft (4) by a directional connector (10), and the directional connector (10) and the arc-shaped directional frame (6) maintain a small deflection along the vertical plane. An air port sleeve (3) is provided at the upper end of the stirring shaft (4).

2. The multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 1, characterized in that, The directional connector (10) is fixedly connected to the stirring shaft (4), and the directional connector (10) is a hemispherical sleeve structure.

3. The multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 1, characterized in that, The arc-shaped directional frame (6) is vertically connected to the stirring shaft (4), and the position of the arc-shaped directional frame (6) corresponds to that of the single air-saving arm (9). The center point of the arc-shaped directional frame (6) and the center point of the directional connecting piece (10) are on the same axis.

4. A multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 3, characterized in that, The arc-shaped directional frame (6) has a vertically arranged directional groove (7), the width of which is equal to the outer diameter of the single throttle arm (9).

5. A multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 1, characterized in that, A pressure-sensing balloon (5) is installed at the other end of the single throttle arm (9). The pressure-sensing balloon (5) is provided with a heat-resistant rubber pad on the outside, and the inside of the pressure-sensing balloon (5) is in communication with the inside of the single throttle arm (9).

6. A multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 5, characterized in that, The linear distance between the pressure-sensitive balloon (5) and the directional connector (10) is equal to or less than the linear distance between the inner wall of the vessel body (2) and the outer wall of the stirring shaft (4), and the pressure-sensitive balloon (5) is oriented and inclined along the horizontal plane.

7. A multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 6, characterized in that, The arc-shaped directional frame (6) is oriented and inclined along the horizontal plane, and the inclination direction of the arc-shaped directional frame (6) is related to the rotation direction of the stirring shaft (4) and the inclination direction of the pressure-sensing bladder (5). The length direction of the single air-saving arm (9) and the slotting direction of the directional groove (7) are parallel to the diameter direction of the vessel body (2).

8. A multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 7, characterized in that, The single throttle arm (9) is slidably mounted on the outer wall position between the pressure-sensing balloon (5) and the arc-shaped directional frame (6), and the single throttle arm (9) is provided with an open wing (11) on the outer wall position between the arc-shaped directional frame (6) and the directional connector (10) and on the outer wall position of the dynamic directional frame (8).

9. A multi-axis cooperative stirred reactor for the production of electronic-grade chemicals according to claim 8, characterized in that, A steering limit structure is provided between the dynamic directional control sleeve (8) and the single throttle arm (9), and the curvature and thickness distribution of each open wing (11) are different.

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