An air knife

Abstract

The present application relates to the technical field of drying device, and particularly relates to a wind knife. The wind knife comprises a lower die, an upper die and a gasket. The lower die is provided with at least one gas inlet channel for accessing gas. A plurality of distribution cavities are sequentially arranged in communication along the gas flow direction. The distribution cavity located at the most upstream of the gas flow direction is in communication with the gas inlet channel. The longitudinal height of the plurality of distribution cavities decreases from the upstream of the gas flow to the downstream of the gas flow. The gas can form a serpentine flow path in the plurality of distribution cavities. The serpentine flow path comprises a low part, a high part and a middle part. The high part is located between the low part and the middle part. The highest point of the low part and the highest point of the middle part are the same and are the lowest point of the high part. The lowest point of the low part is lower than the lowest point of the middle part. The distribution cavity located at the most downstream of the gas flow direction is in communication with a lip. The serpentine flow path is easy to form laminar flow, greatly reduces the generation of turbulent flow, and the time domain fluctuation of the wind speed sprayed by the lip is smaller.

Description

Technical Field

[0001] This invention relates to the field of drying equipment technology, and more specifically to an air knife. Background Technology

[0002] In the perovskite coating process, which includes coating and drying steps, liquid coating die A is typically used first for coating, followed by liquid coating die B for drying. In current production, liquid coating dies A and B have identical structures. The liquid coating die is designed for the perovskite coating liquid, and the uniformity of the liquid within the die meets the requirements of the coating process. However, using the liquid coating die for the drying process is not ideal. This is because liquid coating die B requires compressed air as the drying gas. The compressed air introduced into liquid coating die B easily generates turbulence, leading to unstable gas flow at the outlet of liquid coating die B. Large fluctuations in velocity amplitude occur at individual points, further deteriorating the lateral consistency of the gas flow at the outlet of liquid coating die B. The fundamental reason is that the structure of the liquid coating die B is designed for perovskite coating liquid, which can make the liquid phase material flow more uniformly. The flow direction of compressed air in the liquid coating die B is not the same as that of the liquid, which leads to the deterioration of the lateral consistency of the gas flow at the outlet of the liquid coating die B in the coating and drying process, and in severe cases, it can lead to the failure of coating.

[0003] The industry typically uses perovskite liquid coating dies, which serve a dual purpose: two dies are used to complete the coating and drying processes respectively. For example, the patent document with authorization publication number CN214864866U... Figure 1 The invention discloses a slit-type coating die for perovskite solutions, comprising a left die and a right die fixed together by bolts. Both the left and right dies have protruding lip portions at their bottoms, with an outlet for the perovskite coating solution in the center of the lip portion. A vacuum pipe is located inside the left die, and a negative pressure chamber is formed within the lip portion, with an inner sealing cavity within the negative pressure chamber. The right die contains a first cavity and a second cavity, as well as an inlet channel and a return channel for facilitating the entry and exit of the perovskite coating solution. This multi-cavity design reduces the impact of high-flow-rate solution at the outlet on solution distribution at the lip, ensures stable solution distribution, and effectively shortens the length of the direct flow zone within the die. This reduces hydraulic pressure at the lip while ensuring uniform solution distribution, thereby reducing leakage of the low-viscosity, high-density perovskite coating solution at the lip due to gravity and hydraulic pressure. The above application was also designed with consideration of the uniformity of high flow rate solution distribution. When compressed gas is introduced into its second and third cavities, turbulence is also easily generated, and the longitudinal stability and lateral uniformity of the outlet gas flow rate are poor.

[0004] In summary, there is an urgent need to make targeted improvements to the die head in the coating and drying process, which is of great significance for improving the production efficiency of perovskite coating, reducing product scrap, and lowering manufacturing costs. Summary of the Invention

[0005] The purpose of this invention is to provide an air knife that improves the uniformity of airflow throughout the airflow process, thereby increasing the production efficiency of perovskite coating and reducing product scrap.

[0006] To solve the above-mentioned technical problems, the present invention provides an air knife, including a lower mold, an upper mold, and a gasket located between the lower mold and the upper mold. The lower mold is provided with at least one gas inlet channel for receiving gas, and a plurality of distribution chambers are sequentially connected along the gas flow direction. The distribution chamber located at the upstream end of the gas flow direction is connected to the gas inlet channel. The longitudinal height of the plurality of distribution chambers decreases from upstream to downstream of the gas flow. The gas can form a serpentine flow path in the plurality of distribution chambers. The serpentine flow path includes a low part, a high part, and a middle part, and the high part is located between the low part and the middle part. The highest point of the low part and the highest point of the middle part are the same and the lowest point of the high part. The lowest point of the low part is 8-12 mm lower than the lowest point of the middle part. A lip is formed between the lower mold and the upper mold, and the lip is located at the end of the gas flow. The distribution chamber located at the downstream end of the gas flow direction is connected to the lip.

[0007] Preferably, the volume of the plurality of distribution chambers decreases along the gas flow direction, and the corners of the plurality of distribution chambers are provided with rounded chamfers.

[0008] Preferably, there are at least three distribution chambers, namely a first distribution chamber connected to the gas inlet channel, a third distribution chamber connected to the lip, and a second distribution chamber located between the first and third distribution chambers, with a flow-blocking channel provided between the lip and the third distribution chamber.

[0009] Preferably, the longitudinal heights of the first distribution cavity, the second distribution cavity, and the third distribution cavity decrease progressively, and the longitudinal height of the first distribution cavity is 1.5 to 2.5 times the longitudinal height of the second distribution cavity, and the longitudinal height of the second distribution cavity is 1.5 to 2.5 times the longitudinal height of the third distribution cavity.

[0010] Preferably, the width of the first distribution cavity is 1 to 1.5 times the width of the second distribution cavity, and the width of the second distribution cavity is 1 to 1.5 times the width of the third distribution cavity.

[0011] Preferably, the longitudinal height of the flow obstruction channel is 0.05~0.25mm, and the top of the flow obstruction channel is flush with the top of the third distribution chamber.

[0012] Preferably, the length of the gas inlet channel in the gas flow direction is 1 to 2 times the width of the first distribution cavity, and the length of the flow obstruction channel in the gas flow direction is 1 to 2 times the width of the first distribution cavity.

[0013] Preferably, the first distribution cavity includes a first arc and a second arc, the connection between the first distribution cavity and the second distribution cavity is provided with a third arc and a fourth arc, the second distribution cavity includes a fifth arc and a sixth arc, the connection between the second distribution cavity and the third distribution cavity is provided with a seventh arc and an eighth arc, the third distribution cavity is provided with a ninth arc and a tenth arc, and the connection between the third distribution cavity and the flow obstruction channel is provided with an eleventh arc.

[0014] Preferably, the first distribution cavity, the second distribution cavity, and the third distribution cavity are located between the lower mold and the upper mold; the first distribution cavity and the third distribution cavity are spaced apart on the lower mold, and the second distribution cavity is located on the upper mold and connects the first distribution cavity and the third distribution cavity.

[0015] Preferably, the widths of the first distribution cavity, the second distribution cavity, and the third distribution cavity are the same.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. The depths of the first, second, and third distribution chambers decrease progressively, while the flow velocities increase progressively. Together, the first, second, and third distribution chambers form a serpentine flow path. Compared to the flow paths of existing air knife one and air knife two technologies, the serpentine flow path facilitates laminar flow, greatly reduces the generation of turbulence (vortices, swirls), and results in smaller temporal fluctuations in the wind speed ejected from the lip.

[0018] 2. By matching the dimensions of the first distribution chamber, the second distribution chamber, the third distribution chamber, the flow obstruction channel, and the rounded chamfers of each chamber, the pressure drop difference of each path during lateral distribution can be reduced, which can significantly improve the uniformity of the outlet air velocity.

[0019] 3. It can achieve 97% lateral uniformity of lip outlet air velocity without adjustment mechanism. It has a simple structure, is easy to process, and the cost of air knife is lower than that of air knife with adjustment mechanism. At the same time, the elimination of adjustment also reduces the difficulty of debugging. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure involved in the background technology;

[0021] Figure 2 This is a schematic diagram of the structure of the first type of air knife in the prior art;

[0022] Figure 3 This is a schematic diagram of the gas flow direction in the existing technology of air knife one;

[0023] Figure 4This is a schematic diagram of the structure of the second air blade in the prior art;

[0024] Figure 5 This is a schematic diagram of the gas flow direction of the second air knife in the prior art;

[0025] Figure 6 This is a schematic diagram of the structure of the present invention;

[0026] Figure 7 This is a schematic diagram of the lower mold structure of the present invention;

[0027] Figure 8 This is a schematic diagram of the upper mold structure of the present invention;

[0028] Figure 9 This is a side sectional view of the present invention;

[0029] Figure 10 This is a three-dimensional rendering of the distribution chamber of the present invention;

[0030] Figure 11 This is a diagram illustrating the airflow effect in the distribution chamber of the present invention;

[0031] Figure 12 This is a schematic diagram of the gas flow direction in the die head of the present invention;

[0032] Figure 13 yes Figure 12 Top view of gas flow direction in the middle mold head;

[0033] Figure 14 These are test data graphs for three types of air blades;

[0034] Figure 15 This is a schematic diagram of the lateral wind speed distribution at 1cm from the lip of the first wind knife in the prior art;

[0035] Figure 16 This is a schematic diagram of the lateral wind speed distribution at 1cm from the lip of the second wind knife in the prior art;

[0036] Figure 17 This is a schematic diagram of the lateral wind speed distribution at 1cm from the lip of the third wind knife of the present invention;

[0037] Figure 18 This is a schematic diagram of the lateral wind speed distribution at 3cm from the lip of the third wind knife of the present invention;

[0038] Explanation of reference numerals in the attached drawings: 1. Lower mold; 11. First distribution cavity; 12. Third distribution cavity; 13. Gas inlet channel; 2. Upper mold; 21. Second distribution cavity; 3. Gasket; 4. Lip; 5. Flow obstruction channel; 61. First arc; 62. Second arc; 63. Third arc; 64. Fourth arc; 65. Fifth arc; 66. Sixth arc; 67. Seventh arc; 68. Eighth arc; 69. Ninth arc; 610. Tenth arc; 611. Eleventh arc; 10. Air knife one; 20. Air knife two; 30. Air knife three. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0040] Figure 1 The diagram in the background section shows that when compressed gas is introduced into the second and third cavities, turbulence is easily generated, resulting in poor longitudinal stability and lateral uniformity of the outlet gas flow rate; the time-domain fluctuation of the outlet air velocity is even greater, and the outlet air velocity is uneven.

[0041] During the development of this invention, the air knife 10 was mentioned. Figure 2 This is a schematic diagram of the structure of the air knife 10 in the prior art. The air knife 10 consists of multiple chambers connected on its lower mold, and each chamber has a regular shape. Figure 3 This is a schematic diagram of the gas flow direction of the air knife-10 in the prior art; by Figure 3 It can be seen that there is a vortex in the last chamber of the lower mold, the airflow in the first chamber is not uniform, there is a vortex in the gas flow direction at its lip, and the longitudinal stability and lateral uniformity of the gas flow are poor.

[0042] Based on the Wind Blade 1.10, the researchers designed the Wind Blade 2.20. Figure 4 This is a schematic diagram of the structure of the air knife 20 in the prior art. Based on the air knife 10, the present invention improves the shape of the cavity and reduces the number of cavities to 2. Figure 5 This is a schematic diagram of the gas flow direction of the air knife 2.20. Figure 5 It can be seen that the longitudinal stability and lateral uniformity of the outlet gas flow of air knife 20 are poor; the time domain fluctuation of the outlet air velocity of the lip is large. Neither air knife 10 nor air knife 20 can meet the requirements of the perovskite coating liquid for the air jet of the air knife.

[0043] Through the unremitting efforts of the R&D personnel, the air knife of this invention, namely air knife three 30, was improved. Figures 6-13 As shown, the air knife 30 includes a lower mold 1, an upper mold 2, and a gasket 3. The gasket 3 is located between the lower mold 1 and the upper mold 2. The lower mold 1 is provided with at least one gas inlet channel 13 for gas inlet. Multiple distribution chambers are sequentially arranged along the gas flow direction, with the upstream distribution chamber connected to the gas inlet channel 13. The longitudinal height of the multiple distribution chambers decreases from upstream to downstream of the gas flow. The gas can form a serpentine flow path in the multiple distribution chambers, including a low section, a high section, and a middle section. The high section is located between the low section and the middle section. The highest point of the low section is the same as the highest point of the middle section and is the lowest point of the high section. The height difference between the lowest point of the low section and the lowest point of the middle section is H, where H is 8~12mm. Figure 12 As shown, curve S1 is a serpentine flow path. Point A of curve S1 is at the bottom, point B is at the top, and point C is in the middle. The highest point that point A can reach is at the same height as the highest point that point C can reach, and this highest point is the lowest point of point B. A lip 4 is formed between the lower mold 1 and the upper mold 2, and the lip 4 is located at the end of the gas flow. The distribution cavity located at the downstream end of the gas flow direction is connected to the lip 4.

[0044] The volume of the multiple distribution chambers decreases along the gas flow direction. The decreasing volume of the distribution chambers can gradually increase the gas flow velocity in the air knife 30. In addition, the corners of the multiple distribution chambers are provided with rounded corners to avoid the problem of inconsistent gas flow direction in the cavity of the air knife 10.

[0045] like Figure 7 , Figure 8 , Figure 9 The plurality of distribution chambers shown includes at least three: a first distribution chamber 11, a second distribution chamber 21, and a third distribution chamber 12. The first distribution chamber 11 is connected to the gas inlet channel 13, and the third distribution chamber 12 is connected to the lip 4. The second distribution chamber 21 is located between the first distribution chamber 11 and the third distribution chamber 12. A flow-blocking channel 5 is provided between the lip 4 and the third distribution chamber 12. The first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12 are sequentially connected. Gas passes sequentially through the gas inlet channel 13, the first distribution chamber 11, the second distribution chamber 21, the third distribution chamber 12, and the flow-blocking channel 5 before being blown out from the lip 4. A serpentine flow path is formed in the first distribution chamber 11, the upper part of the serpentine flow path is located in the second distribution chamber 21, and the middle part of the serpentine flow path is located in the third distribution chamber 12.

[0046] The serpentine flow path is formed based on the structural design of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12. This structural design includes the longitudinal height and width of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12, as well as the rounded chamfers within the cavities. For example... Figure 9 As shown, the longitudinal height of the first distribution cavity 11 is H1, the longitudinal height of the second distribution cavity 21 is H2, and the longitudinal height of the third distribution cavity 12 is H3. The height H1 of the first distribution cavity 11 is 1.5 to 2.5 times the height H2 of the second distribution cavity 21, preferably H1 is twice H2; the height H2 of the second distribution cavity 21 is 1.5 to 2.5 times the height H3 of the third distribution cavity 12, preferably H2 is twice H3. The width of the first distribution cavity 11 is b, the width of the second distribution cavity 21 is c, and the width of the third distribution cavity 12 is d, where b is 1 to 1.5 times c, preferably b and c are equal; c is 1 to 1.5 times d, preferably c and d are equal. The design of the longitudinal height and width allows the gas to be evenly distributed laterally in the first distribution chamber 11 and the second distribution chamber 21, and then transformed into laminar flow in the third distribution chamber 12 and the flow obstruction channel 5 until it is ejected from the lip 4. The laminar flow achieves stable outflow and obtains better lateral uniformity of flow velocity and stable ejection in the time domain.

[0047] The longitudinal height of the flow-blocking channel 5 is 0.05~0.25mm, and the top of the flow-blocking channel 5 is flush with the top of the third distribution cavity 12. This design allows the flow-blocking channel 5 to apply frictional resistance to the fluid through the lower surface of the upper mold 2 and the upper surface of the lower mold 1, thereby causing the fluid to be "blocked" at the flow-blocking channel 5, prompting the lateral distribution process of the fluid to occur at the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12. A suitable longitudinal height for the flow-blocking channel 5 can achieve a better lateral distribution effect; the preferred longitudinal height is 0.05mm.

[0048] The length of the gas inlet channel 13 in the gas flow direction is 1 to 2 times the width of the first distribution chamber 11. Figure 9 The length of the gas inlet channel 13 in the gas flow direction is 'a', where 'a' is 1 to 2 times 'b'. The length of the flow-blocking channel 5 in the gas flow direction is 'e', ​​where 'e' is 1 to 2 times 'b', the width of the first distribution cavity 11. This width design allows the flow-blocking channel 5 to apply frictional resistance to the fluid through the lower surface of the upper mold 2 and the upper surface of the lower mold 1, causing the fluid to be "blocked" at the flow-blocking channel 5. This promotes the lateral distribution process of the fluid at the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12. An appropriate value of 'e' can achieve a better lateral distribution effect. Preferably, the length 'e' of the flow-blocking channel 5 in the gas flow direction is 1.33 times the width 'b' of the first distribution cavity 11.

[0049] Figure 9The document also shows the rounded chamfers at the corners of each distribution cavity. The first distribution cavity 11 includes a first arc 61 and a second arc 62. The connection between the first distribution cavity 11 and the second distribution cavity 21 is provided with a third arc 63 and a fourth arc 64. The second distribution cavity 21 includes a fifth arc 65 and a sixth arc 66. The connection between the second distribution cavity 21 and the third distribution cavity 12 is provided with a seventh arc 67 and an eighth arc 68. The third distribution cavity 12 is provided with a ninth arc 69 and a tenth arc 610. The connection between the third distribution cavity 12 and the flow obstruction channel 5 is provided with an eleventh arc 611. The radii of the first arc 61, second arc 62, third arc 63, fourth arc 64, fifth arc 65, sixth arc 66, seventh arc 67, eighth arc 68, ninth arc 69, tenth arc 610, and eleventh arc 611 are all equal to half of H3, which is half the longitudinal height of the third distribution cavity 12. The central angles of the first arc 61, second arc 62, third arc 63, fourth arc 64, fifth arc 65, sixth arc 66, seventh arc 67, eighth arc 68, ninth arc 69, tenth arc 610, and eleventh arc 611 are all 90 degrees. Adding arc angles to the first distribution cavity 11, second distribution cavity 21, and third distribution cavity 12 can form a smooth serpentine flow path, avoiding the formation of vortices or turbulence in the gas at right angles, thereby avoiding temporal velocity instability.

[0050] In a preferred embodiment, the air knife 30 includes an upper mold 2, a gasket 3, and a lower mold 1. A first distribution cavity 11, a second distribution cavity 21, and a third distribution cavity 12 are located between the lower mold 1 and the upper mold 2. The first distribution cavity 11 and the third distribution cavity 12 are spaced apart on the lower mold 1, and the second distribution cavity 21 is located on the upper mold 2 and connects the first distribution cavity 11 and the third distribution cavity 12. The widths of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12 are the same. The longitudinal heights of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12 decrease in a 0.5-fold increment; that is, the height H1 of the first distribution cavity 11 is twice the height H2 of the second distribution cavity 21, and the height H2 of the second distribution cavity 21 is twice the height H3 of the third distribution cavity 12. The lower mold 1 has a gas inlet channel 13, a first distribution chamber 11, and a third distribution chamber 12; the upper mold 2 has a second distribution chamber 21; the first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12 are all obtained by transverse sweeping cut of rounded rectangular cross sections; the upper mold 2, the gasket 3, and the lower mold 1 are fixed by bolts, and the double-row bolt structure has better rigidity, which, combined with the serpentine flow path, results in better air knife performance. The gasket 3 is located between the upper mold 2 and the lower mold 1, forming a slit obstruction channel 5. The end of the obstruction channel 5 is a lip 4. The thinner or longer the obstruction channel 5, the greater the pressure drop and the better the transverse uniformity of the ejected gas flow velocity. In this embodiment, the longitudinal height of the obstruction channel 5 is 0.05 mm; the lower mold 1 is connected to the coating machine's fixed base. Figure 10This is a three-dimensional rendering of the distribution chamber of the present invention, by Figure 10 It can be seen that the gas flow channel in the air knife 30 of the present invention has a serpentine path and the cross-sectional area of ​​the flow channel decreases step by step. Figure 11 This is a diagram illustrating the airflow effect in the distribution chamber of the present invention. Figure 11 It can be seen that the gas forms a serpentine flow in the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12. Figure 12 This is a schematic diagram of the gas flow direction in the die head of the present invention. Figure 12 It can be seen that the gas forms a serpentine flow in the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12, and forms a jet flow at the lip 4, and the flow velocity at the center of the jet is much greater than 40m / s. Figure 13 yes Figure 12 The top view of the gas flow direction of the intermediate mold head, from Figure 13 It can be seen that the gas is mainly laterally distributed in the first distribution chamber 11 and the second distribution chamber 21, and the lateral distribution is completed in the third distribution chamber 12. There is no obvious lateral distribution behavior in the flow obstruction channel 5, and the lateral uniformity of the gas velocity after being ejected from the lip 4 is good. The depths of the first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12 of the air knife 30 decrease step by step, and the flow velocities increase step by step. The first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12 together form a serpentine flow path. Compared with the flow paths of the existing air knife 10 and air knife 20, the serpentine flow path is easier to form laminar flow, which greatly reduces the generation of turbulence (vortices, swirls), and the time-domain fluctuation of the wind velocity ejected from the lip is smaller. By matching the dimensions of the first distribution chamber 11, the second distribution chamber 21, the third distribution chamber 12, the flow obstruction channel 5, and the rounded chamfers of each chamber, the pressure drop difference of each path during lateral distribution can be reduced, which can significantly improve the uniformity of the outlet wind velocity.

[0051] Figure 14 These are test data for three types of air blades, from... Figure 14 It can be seen that the lateral uniformity of the outlet flow velocity of the air knife 30 is better than that of the air knife 10 and the air knife 20, and the air knife 30 still has a good effect at a distance of 3cm from the lip 4.

[0052] Figure 15 This is a test result image of the Wind Blade 10 at a distance of 1cm from the lip. Figure 15 The curve indicates that the outlet velocity of the air knife 10 has poor lateral uniformity.

[0053] Figure 16 This is a test result image of the Wind Blade 2.20 at 1cm from the lip. Figure 16 The curve indicates that the lateral uniformity of the outlet velocity of the second air knife 20 is poor.

[0054] Figure 17 This is a test result image of the Wind Blade 3.30 at 1cm from the lip. Figure 17The curve indicates that the outlet velocity of the air knife 330 has good lateral uniformity.

[0055] Figure 18 This is a test result image of the Wind Blade 3.30 at a distance of 3cm from the lip. Figure 18 The curve shows that the outlet velocity uniformity of the air knife 30 is better in the lateral direction than that of the air knife 30 at 1 cm. This indicates that the gas velocity uniformity of the air knife 30 at 3 cm from the lip is better than that at 1 cm from the lip.

[0056] After testing Figure 10 , Figure 11 , Figure 12 , Figure 13 This invention demonstrates that the structure of the air knife 30 fully meets the process requirements for drying perovskite coating liquid. By opening a second distribution cavity 21 on the upper mold 2, and through the shape and size matching of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12, the gas flow within the second distribution cavity 21 and the third distribution cavity 12 is laminar, improving the longitudinal stability and lateral uniformity of the outlet gas flow rate. The longitudinal stability and lateral uniformity of the outlet gas flow rate are good, with lateral consistency exceeding 97%. The gas forms a serpentine flow path through the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12. The structural design of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12 facilitates laminar flow, which is orderly and stable; conversely, turbulent flow is disordered and fluctuating. Laminar flow is beneficial for improving longitudinal stability, providing a foundation for improving lateral uniformity. Through the combination of the first distribution cavity 11, the second distribution cavity 21, and the third distribution cavity 12, the lateral and longitudinal uniformity are improved.

Claims

1. An air knife, comprising a lower mold (1), an upper mold (2), and a gasket (3) located between the lower mold (1) and the upper mold (2), characterized in that: The lower mold (1) is provided with at least one gas inlet channel (13) for gas access, and multiple distribution chambers are sequentially connected along the gas flow direction. The distribution chamber located at the upstream of the gas flow direction is connected to the gas inlet channel (13). The longitudinal height of the multiple distribution chambers decreases from the upstream of the gas flow to the downstream of the gas flow. The gas can form a serpentine flow path in the multiple distribution chambers. The serpentine flow path includes a low part, a high part and a middle part. The high part is located between the low part and the middle part. The highest point of the low part and the highest point of the middle part are the same and the lowest point of the high part. The lowest point of the low part is 8~12mm lower than the lowest point of the middle part. A lip (4) is formed between the lower mold (1) and the upper mold (2). The lip (4) is located at the end of the gas flow. The distribution chamber located at the downstream of the gas flow direction is connected to the lip (4).

2. The air knife according to claim 1, characterized in that: The volume of the multiple distribution chambers decreases along the gas flow direction, and each of the multiple distribution chambers has rounded chamfers at its corners.

3. The air knife according to claim 2, characterized in that: The plurality of distribution chambers include at least three, namely a first distribution chamber (11) connected to the gas inlet channel (13), a third distribution chamber (12) connected to the lip (4), and a second distribution chamber (21) located between the first distribution chamber (11) and the third distribution chamber (12). A flow-blocking channel (5) is provided between the lip (4) and the third distribution chamber (12).

4. The air knife according to claim 3, characterized in that: The longitudinal heights of the first distribution cavity (11), the second distribution cavity (21), and the third distribution cavity (12) decrease progressively, and the longitudinal height of the first distribution cavity (11) is 1.5 to 2.5 times the longitudinal height of the second distribution cavity (21), and the longitudinal height of the second distribution cavity (21) is 1.5 to 2.5 times the longitudinal height of the third distribution cavity (12).

5. The air knife according to claim 4, characterized in that: The width of the first distribution cavity (11) is 1 to 1.5 times the width of the second distribution cavity (21), and the width of the second distribution cavity (21) is 1 to 1.5 times the width of the third distribution cavity (12).

6. The air knife according to claim 5, characterized in that: The longitudinal height of the flow obstruction channel (5) is 0.05~0.25mm, and the top of the flow obstruction channel (5) is flush with the top of the third distribution cavity (12).

7. The air knife according to claim 6, characterized in that: The length of the gas inlet channel (13) in the gas flow direction is 1 to 2 times the width of the first distribution cavity (11), and the length of the flow obstruction channel (5) in the gas flow direction is 1 to 2 times the width of the first distribution cavity (11).

8. The air knife according to claim 3, characterized in that: The first distribution cavity (11) includes a first arc (61) and a second arc (62). The connection between the first distribution cavity (11) and the second distribution cavity (21) is provided with a third arc (63) and a fourth arc (64). The second distribution cavity (21) includes a fifth arc (65) and a sixth arc (66). The connection between the second distribution cavity (21) and the third distribution cavity (12) is provided with a seventh arc (67) and an eighth arc (68). The third distribution cavity (12) is provided with a ninth arc (69) and a tenth arc (610). The connection between the third distribution cavity (12) and the flow obstruction channel (5) is provided with an eleventh arc (611).

9. The air knife according to claim 3, characterized in that: The first distribution cavity (11), the second distribution cavity (21) and the third distribution cavity (12) are located between the lower mold (1) and the upper mold (2); the first distribution cavity (11) and the third distribution cavity (12) are spaced apart on the lower mold (1), and the second distribution cavity (21) is located on the upper mold (2) and connects the first distribution cavity (11) and the third distribution cavity (12).

10. The air knife according to claim 5, characterized in that: The widths of the first distribution cavity (11), the second distribution cavity (21), and the third distribution cavity (12) are the same.

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