A coating apparatus

Abstract

This invention provides a coating equipment, relating to the field of coating technology, to solve the technical problem of uneven film thickness. The coating equipment includes a tube body with an open end, comprising multiple sequentially connected tube segments. Each tube segment has at least one air inlet pipe on its inner wall, and each air inlet pipe receives air from a portion near the open end via a connecting pipe. Each air inlet pipe includes a main pipe extending away from the open end and at least one branch pipe. The branch pipe includes a single-layer sleeve or multiple coaxially spaced sleeves, with multiple air outlets formed on the sleeves. The innermost sleeve in the single-layer or multi-layer sleeve is connected to the main pipe. When the branch pipe includes multiple sleeves, the air outlets of adjacent sleeves are staggered. Along the direction away from the open end, the number of sleeve layers in each tube segment decreases sequentially. This coating equipment can improve the uniformity of film thickness on a substrate.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, and in particular to a coating equipment. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] A tube furnace is a device used to coat the surface of materials. Gaseous reactants are introduced into the substrate surface inside the furnace. Under high temperature and other conditions, the gaseous reactants undergo a chemical reaction, generating a solid thin film that is deposited on the substrate surface. For example, silane gas is introduced onto the surface of a silicon wafer; at high temperature, the silane decomposes and forms a silicon thin film on the wafer surface.

[0004] In related technologies, when gaseous reactants are introduced into the coating tube furnace, the gaseous reactants have low uniformity of distribution in the furnace, resulting in uneven film thickness on the substrate. Utility Model Content

[0005] The purpose of this invention is to provide a coating equipment to solve the technical problem of uneven film thickness.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] This utility model provides a coating device, including a tube body with an open end, the tube body having multiple tube segments, and each tube segment having at least one air inlet pipe on its inner wall, each air inlet pipe receiving air from a portion near the open end through a connecting pipe.

[0008] The air intake pipe includes a main pipe extending in a direction away from the opening end and at least one branch pipe. The branch pipe includes a single-layer sleeve or multiple layers of the sleeve arranged coaxially and spaced apart. Multiple air outlets are formed on the sleeve. The innermost sleeve in the single-layer sleeve or multiple layers of the sleeve is connected to the main pipe.

[0009] When the branch pipe includes multiple layers of the sleeve, the air outlets of two adjacent layers of the sleeve are staggered.

[0010] Along the direction away from the opening end, the number of sleeve layers in each of the pipe segments decreases sequentially.

[0011] According to at least one embodiment of the present invention, the branch pipe extends along the inner wall of the pipe section and in a direction away from the opening end.

[0012] According to at least one embodiment of the present invention, the cross-section of the pipe segment in the direction perpendicular to its axis is circular, and the central axis of the branch pipe includes a helix, the helix angle of which ranges from 5° to 85°.

[0013] According to at least one embodiment of the present invention, the branch pipes are provided on both sides of the main pipe, and the branch pipes on the same main pipe are staggered.

[0014] According to at least one embodiment of this utility model, the number of pipe segments is 2 to 9; and / or,

[0015] The number of branches on the same main pipe is 4 to 10; and / or,

[0016] The inner diameter of the innermost sleeve of the branch pipe ranges from 3mm to 8mm; and / or,

[0017] The inner diameter of the outermost sleeve of the branch pipe ranges from 9mm to 15mm.

[0018] According to at least one embodiment of the present invention, the diameter of the vent hole of the sleeve ranges from 0.5 mm to 1.5 mm; and / or,

[0019] The free end of the sleeve is a closed end; and / or,

[0020] The multiple air outlets are evenly distributed on the sleeve.

[0021] According to at least one embodiment of the present invention, the pipe segment has a plurality of air intake pipes, and the plurality of air intake pipes are evenly distributed along the circumference of the pipe segment.

[0022] According to at least one embodiment of the present invention, each of the pipe segments has the same number of main pipes and they correspond one-to-one, the central axes of the corresponding main pipes coincide, and / or,

[0023] The main tube is attached to the inner wall of the tube body.

[0024] According to at least one embodiment of the present invention, the connecting tube is attached to the inner wall of the tube body, and the connecting tube includes a straight section extending in a direction away from the open end and an arc-shaped section extending circumferentially along the inner wall of the tube body.

[0025] The straight section is located between two adjacent main pipes within the pipe section it passes through. One end of the arc-shaped section is connected to the corresponding straight section, and the other end is connected to the end of the main pipe within the corresponding pipe section facing the opening.

[0026] According to at least one embodiment of the present invention, the coating equipment further includes an air supply device and a plurality of flow controllers, and each of the connecting pipes is connected to the air supply device through a corresponding flow controller.

[0027] In one or more technical solutions provided in the exemplary embodiments of this utility model, at least one of the following beneficial effects can be achieved.

[0028] The coating equipment of the present invention includes a tube body with an open end, the tube body having multiple tube segments, and at least one air inlet pipe provided on the inner wall of each tube segment. The air inlet pipes are connected to an external air source at a location near the open end via connecting pipes. That is, the air inlet pipe of each tube segment takes in air from the open end, or in other words, the gas in the tube body generally flows from the open end to the direction away from the open end. The inlet pipe includes a main pipe extending away from the open end and branch pipes connected to the main pipe. The branch pipes can include a single-layer sleeve or multiple coaxial sleeves spaced apart. The outlet holes of adjacent sleeves in the multiple sleeves are staggered. When gas passes through the inlet hole of the innermost sleeve, the airflow is evenly dispersed, then it enters the next innermost sleeve and converges until full. Subsequently, it passes through the inlet hole of the next innermost sleeve, where the airflow is again evenly dispersed. This process is repeated until the gas exits from the inlet hole of the outermost sleeve and enters the pipe body, achieving flow rate control after uniform flow and pressure stabilization. In other words, the more sleeve layers there are, the better it is for uniform flow control of gases with high velocity or flow rate. Based on this, by successively decreasing the number of sleeve layers in each pipe section away from the open end, the flow velocity in areas with high velocity, such as the pipe section near the open end, can be effectively controlled, resulting in uniform outlet time and thus uniform gas distribution throughout the pipe body, thereby improving the uniformity of the coating thickness on the substrate. Attached Figure Description

[0029] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0030] Figure 1 This is an isometric structural schematic diagram of the coating equipment according to an embodiment of the present utility model;

[0031] Figure 2 This is a cross-sectional structural schematic diagram of the coating equipment according to an embodiment of the present utility model;

[0032] Figure 3 This is an isometric structural diagram of some components of the coating equipment according to an embodiment of the present utility model;

[0033] Figure 4AThis is an isometric structural schematic diagram of the first branch pipe according to an embodiment of the present utility model;

[0034] Figure 4B This is a cross-sectional structural schematic diagram of the first branch pipe according to an embodiment of the present utility model;

[0035] Figure 5A This is an isometric structural schematic diagram of the second branch pipe according to an embodiment of the present utility model;

[0036] Figure 5B This is a cross-sectional structural schematic diagram of the second branch pipe according to an embodiment of the present utility model;

[0037] Figure 6A This is an isometric structural schematic diagram of the third branch pipe according to an embodiment of the present utility model;

[0038] Figure 6B This is a cross-sectional structural schematic diagram of the third branch pipe according to an embodiment of the present utility model;

[0039] Figure 7 This is a side view of the coating equipment according to an embodiment of the present invention.

[0040] Figure label:

[0041] 10. First pipe section; 11. First main pipe; 12. First branch pipe;

[0042] 20. Second pipe section; 21. Second main pipe; 22. Second branch pipe;

[0043] 30. Third pipe section; 31. Third main pipe; 32. Third branch pipe;

[0044] 41. First connecting pipe; 42. Second connecting pipe; 421. Second straight section; 422. Second arc-shaped section; 43. Third connecting pipe; 431. Third straight section; 432. Third arc-shaped section;

[0045] 50. Flow controller;

[0046] 60. Sleeve; 61. Air inlet;

[0047] 70. Open end. Detailed Implementation

[0048] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0049] In the photovoltaic field, coating equipment is used to coat silicon wafers for photovoltaic cells to improve photoelectric conversion efficiency. For example, the silicon wafer is placed in a coating tube furnace, and process gases are introduced. After high-temperature ionization, the desired film layer is formed on the silicon wafer surface. The remaining reaction gases are then extracted from the furnace body through a vacuum vent at the tail end. Since the process gases are introduced from the furnace opening, they flow roughly along the axis of the tube furnace. However, the inlet pipes in related technologies often fail to ensure uniform airflow distribution throughout the furnace, resulting in uneven film thickness on the silicon wafer.

[0050] To address the aforementioned issues, the coating equipment provided by the exemplary embodiment of this utility model lays branch pipes with different numbers of sleeves in different pipe sections according to the gas flow distribution along the pipe axis, thereby producing different uniform flow effects and achieving uniform airflow distribution throughout the pipe, thus improving the uniformity of film thickness.

[0051] It should be noted that the coating equipment provided in the exemplary embodiment of this utility model is described using the coating of photovoltaic cells as an example, but is not limited thereto.

[0052] Figure 1 This is an isometric structural schematic diagram of the coating equipment according to an embodiment of the present utility model; Figure 2 This is a cross-sectional structural schematic diagram of the coating equipment according to an embodiment of the present utility model; Figure 3 This is an isometric structural diagram of some components of the coating equipment according to an embodiment of the present invention. (Combined with...) Figures 1-3 As shown, the coating equipment provided in the exemplary embodiment of this utility model includes a tube body with an open end 70. The tube body has multiple tube segments, and each tube segment has at least one air inlet pipe on its inner wall. Each air inlet pipe is connected to a portion near the open end 70 for air intake. The air inlet pipe includes a main pipe extending in a direction away from the open end 70 and at least one branch pipe. The branch pipe includes a single-layer sleeve 60 or multiple coaxial and spaced-apart sleeves 60. Multiple air outlets are formed on the sleeves 60. The innermost sleeve 60 of the single-layer sleeve 60 or multiple sleeves 60 is connected to the main pipe. When the branch pipe includes multiple sleeves 60, the air outlets of adjacent sleeves 60 are staggered. In the direction away from the open end 70, the number of sleeves 60 in each tube segment decreases sequentially.

[0053] In practical applications, the number of pipe segments depends on the actual airflow distribution. For example, there can be 2, 3, 4, 5, 6, 7, 8, or 9 pipe segments. The following description uses 3 pipe segments as an example. For instance, the first pipe segment 10, the second pipe segment 20, and the third pipe segment 30 are arranged along the direction away from the opening end 70 of the pipe body.

[0054] The number of sleeves 60 included in the branch pipe is also determined according to the actual airflow uniformity required. For example, the branch pipe can have 2, 3, 4, 5, 6, 7, 8, or 9 layers of sleeves 60, or it can be a single-layer sleeve 60. The following description uses the example of the first branch pipe 12 in the first pipe section 10 having 3 nested sleeves 60, the second branch pipe 22 in the second pipe section 20 having 2 nested sleeves 60, and the third branch pipe 32 in the third pipe section 30 having a single-layer sleeve 60, but it is not limited to this.

[0055] When the process gas enters the first pipe section 10 from the first connecting pipe 41 near the opening end 70 through the first branch pipe 12, the innermost sleeve 60 is connected to the first connecting pipe 41. The gas is first split through the air inlet 61 of the innermost sleeve 60 and then merges in the space between the second inner sleeve 60 and the innermost sleeve 60 until it is full. Then it is split again through the air inlet 61 of the second inner sleeve 60 (which is offset from the air inlet 61 of the innermost sleeve 60). Then it enters the space between the second inner sleeve 60 and the outer sleeve 60 until it is full. Then it enters the pipe body through the air inlet 61 of the outer sleeve 60 (which is offset from the air inlet 61 of the second inner sleeve 60). After the uniform flow and pressure stabilization of the three sleeves 60, the airflow in the first pipe section 10 is effectively controlled.

[0056] When the process gas enters the second pipe section 20 through the second branch pipe 22, the gas flow passes through two layers of sleeves 60 for uniform flow and pressure stabilization before entering the interior of the second pipe section 20. The specific uniform flow process is similar to that of the first branch pipe 12, and will not be described in detail here.

[0057] When the process gas enters the third pipe section 30 through the third branch pipe 32, the gas flow is regulated and uniformly compressed by a single-layer sleeve 60 before entering the interior of the third pipe section 30. Therefore, the gas flow distribution becomes more uneven closer to the opening end 70; for example, the flow velocity is higher closer to the gas source. Thus, using branch pipes with more layers of sleeves 60 for regulated and uniform flow improves the uniformity of gas distribution throughout the pipe, thereby increasing the uniformity of the coating thickness on the substrate. The decreasing number of sleeves 60 in each branch pipe of each pipe section effectively unifies the gas exit time of each pipe section, achieving a uniform atmosphere throughout the pipe and preventing a situation where the coating is thicker near the opening end 70 and thinner further away from the opening end 70.

[0058] In some embodiments, the number of air intake pipes provided on the inner wall of each pipe segment can be one, that is, a first main pipe 11 and one or more first branch pipes 12 connected to the first main pipe 11 are provided in the first pipe segment 10.

[0059] When a first branch pipe 12 is provided on the first main pipe 11, the free end of the first branch pipe 12 extends along the circumference of the inner wall of the first pipe section 10 and in a direction away from the opening end 70 until it extends to the other side of the first main pipe 11. That is, the first branch pipe 12 extends forward at an angle along the airflow direction of the first main pipe 11 and does not strictly form a ring in accordance with the circumferential direction of the inner wall of the first pipe section 10.

[0060] When a plurality of first branch pipes 12 are provided on the first main pipe 11, the free ends of the first branch pipes 12 extend along the circumference of the inner wall of the first pipe section 10 and in a direction away from the opening end 70. The plurality of first branch pipes 12 are arranged on both sides of the first main pipe 11 and are staggered along the extension direction of the first main pipe 11. Two first branch pipes 12 that are adjacent in the axial direction of the first main pipe 11 and located on both sides of the first main pipe 11 extend to both sides and in a direction away from the opening end 70. The orthographic projections of the two first branch pipes 12 on the cross section of the pipe body overlap or form a continuous pattern, so that the gas distribution in the first pipe section 10 is uniform.

[0061] For example, each of the first branch pipes 12 on the first main pipe 11 is evenly distributed along the axial direction of the first main pipe 11.

[0062] In other embodiments, the number of air inlets provided on the inner wall of each pipe section can be multiple, such as 2, 3, 4, 5, 6, 7, 8, or 9 air inlets. Each main pipe is attached to the inner wall of the pipe body, which facilitates material feeding into the pipe body.

[0063] For example, the first pipe section 10 is provided with 5 air intake pipes attached to the inner wall, that is, 5 first main pipes 11. The 5 first main pipes 11 are evenly distributed along the circumference of the inner wall of the first pipe section 10 and attached to the inner wall. The first branch pipes 12 on both sides of each first main pipe 11 extend to the other two adjacent first main pipes 11 until they are close to or attached to the adjacent first main pipes 11.

[0064] like Figure 1 As shown, when the cross-section of the pipe is circular, the central axis of the first branch pipe 12 may include a helix. The helix angle ranges from 5° to 85°, for example, it can be 10°, 15°, 30°, 45°, 60°, 75°, 80°, etc. The helix angle refers to the angle between the generatrix of the cylinder containing the helix and the helix itself; that is, the smallest angle formed by the helix and the generatrix of the cylinder during the helix's upward rotation around the cylinder. Within the aforementioned range of helix angles, the central axis of the first branch pipe 12 can achieve a more uniform airflow distribution. Preferably, the helix angle is 45°.

[0065] For example, the number of first branch pipes 12 on the same first main pipe 11 is 4 to 10, such as 4, 6, 8 or 10, and the number of first branch pipes 12 on both sides of the same first main pipe 11 is the same.

[0066] Figure 4A This is an isometric structural schematic diagram of the first branch pipe 12 according to an embodiment of the present utility model; Figure 4B This is a cross-sectional view of the first branch pipe 12 according to an embodiment of the present invention. See also... Figure 4A and Figure 4B The inner diameter d1 of the innermost sleeve 60 of the first branch pipe 12 ranges from 3mm to 8mm, for example, it can be 3.5mm, 4mm, 5mm, 6mm, 6.35mm, 7mm, etc.; the inner diameter d3 of the outermost sleeve 60 of the first branch pipe 12 ranges from 9mm to 15mm, for example, it can be 9.5mm, 10mm, 12mm, 12.7mm, 13mm, 14mm, etc.

[0067] Figure 5A This is an isometric structural schematic diagram of the second branch pipe 22 according to an embodiment of the present utility model; Figure 5B This is a cross-sectional view of the second branch pipe 22 according to an embodiment of the present invention. See also... Figure 5A and Figure 5B The inner diameter d1 of the innermost sleeve 60 of the first branch pipe 12 ranges from 3mm to 8mm, for example, it can be 3.5mm, 4mm, 5mm, 6mm, 6.35mm, 7mm, etc. The inner diameter d2 of the outermost sleeve 60 of the second branch pipe 22 ranges from 6mm to 13mm, for example, it can be 6.5mm, 7mm, 8mm, 9mm, 10mm, 12mm, 12.7mm, etc.

[0068] Figure 6A This is an isometric structural schematic diagram of the third branch pipe 32 according to an embodiment of the present utility model; Figure 6B This is a cross-sectional view of the third branch pipe 32 according to an embodiment of the present invention. See also... Figure 6A and Figure 6B The inner diameter d1 of the sleeve 60 of the first branch pipe 12 is in the range of 3mm to 8mm, for example, it can be 3.5mm, 4mm, 5mm, 6mm, 6.35mm, 7mm, etc.

[0069] In some implementations, see Figures 4A-6B The diameter of the vent hole of sleeve 60 ranges from 0.5mm to 1.5mm, for example, it can be 0.65mm, 0.7mm, 0.8mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, etc.

[0070] In some implementations, see Figures 4A-6B The free end of the sleeve 60 is a closed end, and multiple vent holes are evenly distributed on the sleeve 60. For example, the free end of the sleeve 60 may also have vent holes, that is, multiple vent holes are evenly distributed on the entire sleeve 60.

[0071] In some embodiments, the air inlets in the second pipe section 20 and the third pipe section 30 are arranged in the same way and in the same number as the air inlet in the first pipe section 10, and the main pipes of each pipe section correspond one-to-one, with the central axes of the corresponding main pipes of each pipe section coinciding, so that the flow rate of each branch pipe in each pipe section can be controlled and the air can be distributed evenly. For example, the number of main pipes in the second pipe section 20, the third pipe section 30, and the first pipe section 10 is 5 each, and the circumferential positions of the 5 main pipes in the first pipe section 10 are the same as the circumferential positions of the 5 main pipes in the second pipe section 20 and the circumferential positions of the 5 main pipes in the third pipe section 30.

[0072] See Figure 1 and Figure 3 The first main pipe 11 is connected to the external air source through the first connecting pipe 41, which passes through the pipe body near the opening end 70.

[0073] See Figure 1 and Figure 2 The second main pipe 21 is connected to the air source via a second connecting pipe 42. For example, the second connecting pipe 42 includes a second straight section 421 extending in a direction away from the opening end 70 and a second arc-shaped section 422 extending circumferentially along the inner wall of the pipe body. The second straight section 421 is located between two adjacent first main pipes 11 (adjacent rows of first branch pipes 12) within the first pipe section 10 it passes through. One end of the second arc-shaped section 422 is connected to the corresponding second straight section 421, and the other end is connected to the end of the second main pipe 21 within the second pipe section 20 facing the opening end 70. This arrangement can minimize obstruction of the airflow distribution in the first pipe section 10 through which the second straight section 421 passes.

[0074] See also Figure 2The third main pipe 31 is connected to the air source via a third connecting pipe 43. For example, the third connecting pipe 43 includes a third straight section 431 extending in a direction away from the opening end 70 and a third arc-shaped section 432 extending circumferentially along the inner wall of the pipe body. The third straight section 431 is located between two adjacent first main pipes 11 (adjacent rows of first branch pipes 12) in the first pipe section 10 and between two adjacent second main pipes 21 (adjacent rows of second branch pipes 22) in the second pipe section 20. One end of the third arc-shaped section 432 is connected to the corresponding third straight section 431, and the other end is connected to the end of the third main pipe 31 in the third pipe section 30 facing the opening end 70. This arrangement can minimize the obstruction of the airflow distribution in the first pipe section 10 and the second pipe section 20 through which the third straight section 431 passes.

[0075] See also Figure 1 The coating equipment also includes an air supply device and multiple flow controllers 50, with each connecting pipe connected to the air supply device via a corresponding flow controller 50.

[0076] For example, the flow controller 50 can be a flow meter, a pneumatic valve, etc. By setting the flow controller 50 on each connecting pipe, the flow rate of the air inlet pipe in each pipe section can be further precisely controlled by adjusting the amount of air inlet, so as to achieve a uniform effect of gas in the pipe body, improve the airflow environment and make the coating uniform.

[0077] Figure 7 This is a side view structural schematic diagram of a coating apparatus according to an embodiment of the present utility model. (In conjunction with...) Figure 1 and Figure 7 As shown, five first connecting pipes 41, connected to the first main pipe 11, penetrate the wall of the first pipe section 10 at its opening edge, extend from the inner wall to the outer wall, and then connect to the air source through corresponding pipes (located outside the pipe body). A flow meter is installed on each pipe connected to the first connecting pipe 41 to control the flow rate entering each first main pipe 11. Five pipes connected to the second straight section 421, at the opening edge of the first pipe section 10, extend from the inner wall to the outer wall and continue along the outer wall of the pipe body in a direction away from the opening end 70, eventually connecting to the air source. Each of these five pipes connected to the second straight section 421 is equipped with a pneumatic valve to control the flow rate entering each second main pipe 21 within the second pipe section 20. The arrangement of the five pipes connected to the third straight section 431 and connected to the air source is similar to the arrangement of the five pipes connected to the second straight section 421 and the corresponding pneumatic valve arrangement, and will not be described further here. It should be noted that the arrangement of the pipelines located outside the pipe body for supplying gas to each pipe section does not interfere with each other; they all simply pass through the pipe body from the outside of the pipe body at the opening edge.

[0078] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A coating equipment, characterized in that, The device includes a pipe body with an open end, the pipe body having multiple pipe segments connected in sequence, each pipe segment having at least one air inlet pipe on its inner wall, and each air inlet pipe receiving air from a portion near the open end via a connecting pipe. The air intake pipe includes a main pipe extending in a direction away from the opening end and at least one branch pipe. The branch pipe includes a single-layer sleeve or multiple sleeves arranged coaxially and spaced apart. Multiple air outlets are formed on the sleeve. The innermost sleeve in the single-layer sleeve or multiple sleeves is connected to the main pipe. When the branch pipe includes multiple layers of the sleeve, the air outlets of adjacent two layers of the sleeve are staggered. Along the direction away from the opening end, the number of sleeve layers in each of the pipe segments decreases sequentially.

2. The coating equipment according to claim 1, characterized in that, The branch pipe extends along the inner wall of the pipe section and in a direction away from the opening end.

3. The coating equipment according to claim 2, characterized in that, The cross-section of the pipe section perpendicular to its axis is circular, and the central axis of the branch pipe includes a helix, the helix angle of which ranges from 5° to 85°.

4. The coating equipment according to claim 2, characterized in that, The main pipe has branch pipes on both sides, and the branch pipes on the same main pipe are staggered.

5. The coating equipment according to claim 4, characterized in that, The number of the pipe sections is 2 to 9; and / or, The number of branches on the same main pipe is 4 to 10; and / or, The inner diameter of the innermost sleeve of the branch pipe ranges from 3mm to 8mm; and / or, The inner diameter of the outermost sleeve of the branch pipe ranges from 9mm to 15mm.

6. The coating equipment according to any one of claims 1-5, characterized in that, The diameter of the vent hole of the sleeve ranges from 0.5 mm to 1.5 mm; and / or, The free end of the sleeve is a closed end; and / or, The multiple air outlets are evenly distributed on the sleeve.

7. The coating equipment according to claim 6, characterized in that, The pipe segment has multiple air intake pipes, and the multiple air intake pipes are evenly distributed along the circumference of the pipe segment.

8. The coating equipment according to claim 7, characterized in that, Each of the aforementioned pipe segments has the same number of main pipes, and they correspond one-to-one; the central axes of the corresponding main pipes coincide; and / or, The main tube is attached to the inner wall of the tube body.

9. The coating equipment according to claim 7, characterized in that, The connecting tube is attached to the inner wall of the tube body, and the connecting tube includes a straight section extending away from the open end and an arc-shaped section extending circumferentially along the inner wall of the tube body. The straight section is located between two adjacent main pipes within the pipe section it passes through. One end of the arc-shaped section is connected to the corresponding straight section, and the other end is connected to the end of the main pipe within the corresponding pipe section facing the opening.

10. The coating equipment according to claim 9, characterized in that, The coating equipment also includes an air supply device and multiple flow controllers, with each of the connecting pipes connected to the air supply device via a corresponding flow controller.

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