Air knife

Abstract

The invention relates to the technical field of drying devices, in particular to an air knife. Comprising a lower die, an upper die and a gasket, the lower die is provided with at least one gas inlet channel used for introducing gas, a plurality of communicated distribution cavities are sequentially formed in the gas flowing direction, and the distribution cavity located at the most upstream of the gas flowing direction is communicated with the gas inlet channel; the longitudinal heights of the plurality of distribution cavities are gradually reduced from the airflow upstream to the airflow downstream; gas can form a snakelike flow path in the plurality of distribution cavities, the snakelike flow path comprises a low part, a high part and a middle part, the high part is positioned 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, and the lowest point of the low part is lower than the lowest point of the middle part; and the distribution cavity positioned at the most downstream of the gas flowing direction is communicated with the lip. The snakelike flow path is easy to form laminar flow, turbulent flow is greatly reduced, and the time domain fluctuation of the air speed sprayed out of the lip is smaller.

Description

Technical Field

[0001] The present invention relates to the technical field of drying devices, in particular to an air knife. Background Art

[0002] In the perovskite coating production process, including the coating process and the coating drying process, generally the liquid coating die A is used first to complete the coating process, and the liquid coating die B is used at the back end of the coating process to complete the coating drying process. In actual production, the structures of the liquid coating die A and the liquid coating die B are exactly the same. The liquid coating die is a die designed for the perovskite coating liquid. The uniformity of the perovskite coating liquid in the die can meet the requirements of the coating process, but the drying effect when the liquid coating die is used for the coating drying process is not ideal. This is because the liquid coating die B needs to use compressed air as the drying gas to pass into the die. When compressed air is passed into the liquid coating die B, turbulence is likely to occur, resulting in unstable gas flow at the outlet of the liquid coating die B. A single point has a large flow rate amplitude fluctuation in the time domain, which in turn causes the deterioration of the lateral consistency of the gas flow at the outlet of the liquid coating die B. The essential reason is that the structure of the liquid coating die head B is designed for perovskite coating liquid, which can make the liquid phase material flow more uniformly; the flow direction of the compressed air in the liquid coating die head B is not the same as that of the liquid, resulting in the deterioration of the lateral consistency of the gas flow at the outlet of the liquid coating die head B during the coating and drying process, and in severe cases, the coating is scrapped.

[0003] The industry generally uses a perovskite liquid coating die head, which is a dual-purpose die, that is, two perovskite liquid coating dies complete the coating process and the coating drying process respectively. For example, the patent document with the authorization announcement number CN214864866U, such as Figure 1 The invention discloses a slot-type coating die for a perovskite solution, comprising a left die and a right die fastened together by bolts. A protruding die lip is provided at the bottom of each die, and an outlet for overflowing the perovskite coating solution is provided in the middle of the die lip. A vacuum line is provided within the left die, and a negative pressure chamber is provided within the die lip, with an inner sealed chamber also provided within the negative pressure chamber. A first cavity and a second cavity are provided within the right die, as well as an inlet channel and a return channel for facilitating the flow of the perovskite coating solution. The multi-cavity design reduces the impact of high-flow solution from the outlet on solution distribution at the die lip, ensuring the stability of solution distribution and effectively shortening the length of the direct current zone within the die. This reduces the hydraulic pressure of the solution at the die lip while ensuring uniform solution distribution, thereby reducing leakage of the low-viscosity, high-density perovskite coating solution at the die lip due to gravity and supply hydraulic pressure. The above application is also designed with consideration given to the uniform distribution of high-flow solutions. When compressed gas is introduced into the second and third cavities, turbulence is easily generated, and the longitudinal stability and lateral uniformity of the outlet gas flow 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 reducing manufacturing costs. Summary of the Invention

[0005] The present invention aims to provide an air knife for improving the uniformity of air volume at all locations during air blowing, thereby increasing perovskite coating production efficiency and reducing product scrap.

[0006] In order to solve the above technical problems, the present invention provides a wind knife, comprising 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 accessing gas, and a plurality of distribution chambers are connected in sequence along the gas flow direction, and the distribution chamber located at the upstream of the gas flow direction is connected to the gas inlet channel; the longitudinal heights of the plurality of distribution chambers decrease from the upstream of the air flow to the downstream of the air flow; the gas can form a serpentine flow path in the plurality of distribution chambers, and 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 is the same as the highest point of the middle part and is the lowest point of the high part, and the lowest point of the low part is 8~12mm 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, and the distribution chamber located at the downstream of the gas flow direction is connected to the lip.

[0007] Preferably, the volumes of the multiple distribution chambers decrease along the gas flow direction, and the corners of the multiple distribution chambers are all provided with arc chamfers.

[0008] Preferably, there are at least three of the multiple distribution chambers, which are 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 distribution chamber and the third distribution chamber, and a flow-blocking channel is provided between the lip and the third distribution chamber.

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

[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-blocking channel is 0.05-0.25 mm, and the top of the flow-blocking 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 chamber, and the length of the flow-blocking channel in the gas flow direction is 1 to 2 times the width of the first distribution chamber.

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

[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 arranged on the lower mold at intervals, and the second distribution cavity is arranged on the upper mold and connects the first distribution cavity and the third distribution cavity.

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

[0016] The beneficial effects of the present invention are as follows: 1. The depths of the first, second, and third distribution chambers decrease gradually, and the flow rate increases step by step. Together, the first, second, and third distribution chambers form a serpentine flow path. Compared to the flow paths of the first and second air knives in the prior art, the serpentine flow path facilitates laminar flow, significantly reducing turbulence (eddies and swirls), and resulting in smaller temporal fluctuations in the air velocity ejected from the lip. 2. By matching the dimensions of the first distribution chamber, the second distribution chamber, the third distribution chamber, the flow-blocking channel, and the arc chamfers of each chamber, the pressure drop difference of each path during horizontal distribution can be reduced, which can significantly improve the uniformity of the outlet air velocity; 3. 97% of the lateral uniformity of the lip outlet wind speed can be achieved without an adjustment mechanism. The structure is simple and easy to process. The cost of the air knife is lower than that of the air knife with an adjustment mechanism. At the same time, the lack of adjustment also reduces the difficulty of debugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram involved in the background technology; Figure 2 It is a structural diagram of the wind knife 1 in the prior art; Figure 3 It is a schematic diagram of the gas flow direction of the wind knife 1 in the prior art; Figure 4 It is a structural diagram of the wind knife 2 in the prior art; Figure 5 It is a schematic diagram of the gas flow direction of the second wind knife in the prior art; Figure 6It is a structural schematic diagram of the present invention; Figure 7 It is a schematic diagram of the lower mold structure of the present invention; Figure 8 It is a schematic diagram of the upper mold structure of the present invention; Figure 9 is a side sectional view of the present invention; Figure 10 is a three-dimensional rendering of the distribution chamber of the present invention; Figure 11 This is a rendering of the airflow effect of the distribution chamber of the present invention; Figure 12 Schematic diagram of the gas flow direction of the die head of the present invention; Figure 13 yes Figure 12 Top view of the gas flow direction of the die head; Figure 14 This is the test data graph of three types of air knives; Figure 15 This is a schematic diagram of the horizontal distribution of wind speed at 1 cm from the lip of the wind knife in the prior art; Figure 16 This is a schematic diagram of the horizontal distribution of wind speed at 1 cm from the lip of the wind knife 2 in the prior art; Figure 17 This is a schematic diagram of the horizontal distribution of wind speed at 1 cm from the lip of the wind knife three of the present invention; Figure 18 This is a schematic diagram of the horizontal distribution of wind speed at 3 cm from the lip of the wind knife three of the present invention; Explanation of the accompanying 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-blocking 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 DESCRIPTION

[0018] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described to better illustrate the principles of the invention and its practical application, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for specific applications.

[0019] Figure 1It is a structural diagram involved in the background technology. When compressed gas is introduced into the second and third cavities, turbulence is easily generated, and the longitudinal stability and lateral uniformity of the outlet gas flow are poor; the time domain fluctuation of the lip outlet wind speed is greater, and the outlet wind speed is uneven.

[0020] During the development of this invention, a wind knife 10 was mentioned. Figure 2 1 is a schematic diagram of the structure of the air knife 10 in the prior art. The air knife 10 is a plurality of chambers connected to each other on its lower mold, and each chamber has a regular shape; Figure 3 Schematic diagram of the gas flow direction of the wind knife 10 in the prior art; Figure 3 It can be seen that there is a vortex in the last cavity on the lower mold, the airflow in the first cavity is not uniform, there is a vortex in the gas flow at its lip, and the longitudinal stability and lateral uniformity of the gas flow are poor.

[0021] Based on the Wind Knife 10, the R&D personnel designed the Wind Knife 20. Figure 4 This is a structural diagram of the wind knife 2 20 in the prior art. Based on the wind knife 10, the present invention improves the cavity shape and reduces the number of cavities to 2; Figure 5 This is a schematic diagram of the gas flow of the air knife 20. Figure 5 It can be seen that the longitudinal stability and lateral uniformity of the gas flow at the outlet of wind knife 20 are poor; the time domain fluctuation of the wind speed at the lip outlet is large, and both wind knife 10 and wind knife 20 cannot meet the requirements of the perovskite coating liquid for the air flow ejected by the wind knife.

[0022] After unremitting efforts of R&D personnel, the wind knife of the present invention is improved, namely wind knife 30, such as Figure 6-Figure 13 As shown, the air knife three 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 accessing gas, and a plurality of distribution chambers are provided in sequence along the gas flow direction, and the distribution chamber located at the upstream of the gas flow direction is connected to the gas inlet channel 13; the longitudinal heights of the plurality of distribution chambers decrease from the upstream of the air flow to the downstream of the air flow; the gas can form a serpentine flow path in the plurality of distribution chambers, and 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 is the same as the highest point of the middle part and is the lowest point of the high part, and the height difference between the lowest point of the low part and the lowest point of the middle part is H, and H is 8~12mm, as shown Figure 12 As shown in , curve S1 represents 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 equal to the highest point that point C can reach, and this highest point is the lowest point that point B can reach. A lip 4 is formed between the lower mold 1 and the upper mold 2, and is located at the end of the gas flow. The distribution chamber located farthest downstream in the gas flow direction is connected to the lip 4.

[0023] The volumes of the multiple distribution chambers decrease along the direction of gas flow. The decreasing volumes of the distribution chambers can gradually increase the gas flow rate in the air knife three 30, and the corners of the multiple distribution chambers are provided with arc chamfers to avoid the problem of inconsistent gas flow direction in the cavity of the air knife one 10.

[0024] like Figure 7 、 Figure 8 、 Figure 9 The plurality of distribution chambers shown are at least three, namely 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 and third distribution chambers 11, 12, and a flow-blocking channel 5 is provided between the lip 4 and the third distribution chamber 12. The first, second, and third distribution chambers 11, 21, and 12 are connected in sequence, and gas passes through the gas inlet channel 13, the first, second, and third distribution chambers 11, 21, and 12, and the flow-blocking channel 5 in sequence before being blown out of the lip 4. A serpentine flow path is formed in the first, second, and third distribution chambers 11, 21, and 12, with the lower portion of the serpentine flow path located in the first distribution chamber 11, the upper portion of the serpentine flow path located in the second distribution chamber 21, and the middle portion of the serpentine flow path located in the third distribution chamber 12.

[0025] The formation of the serpentine flow path is based on the structural design of the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12, which includes the longitudinal height, width and arc chamfers of the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12. Figure 9 As shown, the longitudinal height of the first distribution chamber 11 is H1, the longitudinal height of the second distribution chamber 21 is H2, and the longitudinal height of the third distribution chamber 12 is H3. The height H1 of the first distribution chamber 11 is 1.5 to 2.5 times the height H2 of the second distribution chamber 21, preferably H1 is twice H2; the height H2 of the second distribution chamber 21 is 1.5 to 2.5 times the height H3 of the third distribution chamber 12, preferably H2 is twice H3. The width of the first distribution chamber 11 is b, the width of the second distribution chamber 21 is c, and the width of the third distribution chamber 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 above-mentioned design of longitudinal height and width enables the gas to complete the lateral uniform distribution of gas flow in the first distribution chamber 11 and the second distribution chamber 21, and transform into laminar flow in the third distribution chamber 12 and the flow-blocking channel 5 until it is ejected from the lip 4, achieving stable outflow by laminar flow, and obtaining better lateral uniformity of flow velocity and stable ejection in the time domain.

[0026] The vertical height of the blocking channel 5 is 0.05-0.25 mm, and the top of the blocking channel 5 is flush with the top of the third distribution chamber 12. This design allows the blocking channel 5 to exert frictional resistance on 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" in the blocking channel 5 and promoting the lateral distribution of the fluid between the first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12. A suitable vertical height for the blocking channel 5 can achieve good lateral distribution effects, with a preferred vertical height of 0.05 mm.

[0027] 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 central gas inlet channel 13 in the direction of gas flow is a, where a is 1-2 times b. The length of the choke channel 5 in the direction of gas flow is e, which is 1-2 times the width b of the first distribution chamber 11. This width design allows the choke channel 5 to exert frictional resistance on 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 "block" in the choke channel 5 and promoting the lateral distribution of the fluid in the first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12. An appropriate value of e can achieve a better lateral distribution effect. The preferred length e of the choke channel 5 in the direction of gas flow is 1.33 times the width b of the first distribution chamber 11.

[0028] Figure 9 It also shows the arc chamfers at the corners of each distribution chamber. The first distribution chamber 11 includes a first arc 61 and a second arc 62. The third arc 63 and the fourth arc 64 are provided at the connection between the first distribution chamber 11 and the second distribution chamber 21. The second distribution chamber 21 includes a fifth arc 65 and a sixth arc 66. The seventh arc 67 and the eighth arc 68 are provided at the connection between the second distribution chamber 21 and the third distribution chamber 12. The third distribution chamber 12 is provided with a ninth arc 69 and a tenth arc 610. The third distribution chamber 12 is provided with an eleventh arc 611 at the connection between the third distribution chamber 12 and the flow-blocking channel 5. The radius of the first arc 61, the second arc 62, the third arc 63, the fourth arc 64, the fifth arc 65, the sixth arc 66, the seventh arc 67, the eighth arc 68, the ninth arc 69, the tenth arc 610, and the eleventh arc 611 is equal to half of H3, that is, half of the longitudinal height of the third distribution chamber 12. The central angles of the first arc 61, the second arc 62, the third arc 63, the fourth arc 64, the fifth arc 65, the sixth arc 66, the seventh arc 67, the eighth arc 68, the ninth arc 69, the tenth arc 610, and the eleventh arc 611 are all 90 degrees. The addition of arc angles in the first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12 can form a smooth serpentine flow path, avoiding the formation of vortices or turbulence of the gas at right angles, thereby avoiding the generation of flow velocity instability in the time domain.

[0029] A preferred embodiment is that the air knife 30 includes an upper mold 2, a gasket 3, and a lower mold 1, and 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 provided on the upper mold 2 and connects the first distribution cavity 11 and the third distribution cavity 12. The width of the first distribution cavity 11, the width of the second distribution cavity 21, and the width of 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 manner of 0.5 times; 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 die 1 is provided with a gas inlet channel 13, a first distribution chamber 11, and a third distribution chamber 12; the upper die 2 is provided with a second distribution chamber 21. The first distribution chamber 11, the second distribution chamber 21, and the third distribution chamber 12 are all formed by sweeping the cross section of a rounded rectangular shape. The upper die 2, the gasket 3, and the lower die 1 are bolted together. The double-row bolt structure provides enhanced rigidity, and when combined with the serpentine flow path, the air knife performance is improved. The gasket 3 is positioned between the upper die 2 and the lower die 1, forming a narrow choke channel 5, which terminates in a lip 4. The thinner or longer the choke channel 5, the greater the pressure drop and the better the lateral uniformity of the ejected gas velocity. In this embodiment, the longitudinal height of the choke channel 5 is 0.05 mm. The lower die 1 is connected to the fixed base of the coater. Figure 10 is a three-dimensional rendering of the distribution chamber of the present invention, Figure 10 It can be seen that the gas flow path in the air knife 3 30 of the present invention is a serpentine path, and the cross-sectional area of ​​the flow path decreases step by step. Figure 11 This is a diagram showing the airflow effect of 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 It is a schematic diagram of the gas flow direction of 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 flow is much greater than 40m / s. Figure 13 yes Figure 12 Top view of the gas flow in the die head, Figure 13It can be seen that the gas is mainly distributed transversely in the first distribution chamber 11 and the second distribution chamber 21, and is completed transversely in the third distribution chamber 12. There is no obvious transverse distribution behavior in the flow-blocking channel 5, and the transverse uniformity of the flow velocity of the gas after it is 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 wind knife three 30 decrease step by step, and the flow velocity increases 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 lines of the wind knife one 10 and the wind knife two 20 in the prior art, the serpentine flow path is easy to form laminar flow, which greatly reduces the generation of turbulence (eddy current, swirl), and the time domain fluctuation of the wind speed 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-blocking channel 5, and the arc chamfers of each cavity, the pressure drop difference of each path during transverse distribution can be reduced, which can significantly improve the uniformity of the outlet wind speed.

[0030] Figure 14 The test data of three types of air knives are Figure 14 It can be seen that the lateral uniformity of the outlet flow rate of wind knife three 30 is better than that of wind knife one 10 and wind knife two 20, and wind knife three 30 still has a good effect at 3 cm away from the lip 4.

[0031] Figure 15 This is the test result of Air Knife 10 at 1cm from the lip. Figure 15 The middle curve shows that the lateral uniformity of the outlet flow velocity of air knife 10 is poor.

[0032] Figure 16 This is the test result of the air knife 20 at 1cm from the lip. Figure 16 The middle curve shows that the lateral uniformity of the outlet flow velocity of the air knife 2 20 is poor.

[0033] Figure 17 This is the test result of Air Knife 30 at 1cm from the lip. Figure 17 The middle curve shows that the outlet flow velocity of the air knife 30 has good lateral uniformity.

[0034] Figure 18 This is the test result of Air Knife 30 at 3cm from the lip. Figure 18 The middle curve shows that the lateral uniformity of the outlet flow rate of Wind Knife 30 is good, and is better than the uniformity of Wind Knife 30 at 1 cm, which means that the gas flow rate uniformity of Wind Knife 30 at 3 cm of the lip is better than that of Wind Knife 30 at 1 cm of the lip.

[0035] After testing, Figure 10 、 Figure 11 、 Figure 12 、 Figure 13It is explained that the structure of the air knife 30 of the present invention fully meets the process requirements for drying the perovskite coating liquid. By opening a second distribution chamber 21 on the upper mold 2 and matching the shapes and sizes of the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12, the gas flow in the second distribution chamber 21 and the third distribution chamber 12 is made laminar, which improves the longitudinal stability and transverse uniformity of the outlet gas flow. The longitudinal stability and transverse uniformity of the outlet gas flow are good, and the transverse consistency can be better than 97%. The gas forms a serpentine flow path through the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12. The structural design of the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12 makes it easy to form laminar flow, which is orderly and stable; on the contrary, turbulent flow is disordered and fluctuating; laminar flow is conducive to improving longitudinal stability and provides a basis for improving transverse consistency; through the matching of the first distribution chamber 11, the second distribution chamber 21 and the third distribution chamber 12, the transverse and longitudinal uniformity are improved.

Claims

1. An air knife, comprising a lower die (1), an upper die (2), and a gasket (3) located between the lower die (1) and the upper die (2), characterized in that: The lower mold (1) is provided with at least one gas inlet channel (13) for receiving gas, and a plurality of distribution chambers are sequentially provided along the gas flow direction, wherein the distribution chamber located at the most upstream of the gas flow direction is connected to the gas inlet channel (13); the longitudinal heights of the plurality of distribution chambers decrease 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 chambers, wherein 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 is the same as the highest point of the middle part and is the lowest point of the high part, and the lowest point of the low part is 8 to 12 mm lower than the lowest point of the middle part; 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, and the distribution chamber located at the most downstream of the gas flow direction is connected to the lip (4).

2. The air knife according to claim 1, characterized in that: The volumes of the multiple distribution chambers decrease along the gas flow direction, and the corners of the multiple distribution chambers are all provided with arc chamfers.

3. The air knife according to claim 2, characterized in that: There are at least three of the multiple distribution chambers, which are 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 chamber (11), the second distribution chamber (21), and the third distribution chamber (12) decrease gradually, and the longitudinal height of the first distribution chamber (11) is 1.5 to 2.5 times the longitudinal height of the second distribution chamber (21), and the longitudinal height of the second distribution chamber (21) is 1.5 to 2.5 times the longitudinal height of the third distribution chamber (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-blocking channel (5) is 0.05-0.25 mm, and the top of the flow-blocking channel (5) is flush with the top of the third distribution chamber (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 chamber (11), and the length of the flow-blocking channel (5) in the gas flow direction is 1 to 2 times the width of the first distribution chamber (11).

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

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 arranged on the lower mold (1) at intervals, and the second distribution cavity (21) is arranged on the upper mold (2) and communicates with the first distribution cavity (11) and the third distribution cavity (12).

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

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