Small-diameter air floating roller with stable flow and preparation method of small-diameter air floating roller

Abstract

The invention discloses a small-diameter air floating roller with stable flow and a preparation method of the small-diameter air floating roller. The small-diameter air floating roller with stable flow comprises an air floating roller, a plurality of throttling nozzles, a partition plate and two sets of pressure regulating valves, the air floating roller is of a hollow cavity structure with openings in the two ends; a plurality of mounting grooves are formed in the outer side of the inner cavity in the axial direction and the circumferential direction at equal intervals in an array mode, through holes are formed in the bottoms of the mounting grooves, the throttling nozzles are arranged in the mounting grooves, and the spraying directions of the multiple throttling nozzles distributed in the circumferential direction at intervals intersect with the circumferential direction; and the throttling nozzle is communicated with the inner cavity through the through hole. According to the small-diameter air floating roller with the stable flow, the air floating pressure on a thin base material is uniform, the problem that in the prior art, when an air floating roller suspends the thin base material, floating is prone to being unstable is effectively solved, and the coating speed of the thin base material is increased.

Description

Technical Field

[0001] This invention relates to the field of air flotation roller technology, and in particular to a small-diameter air flotation roller with stable flow rate and its preparation method. Background Technology

[0002] In industries such as lithium batteries, the transfer and conveying of thin substrates are involved. Commonly used contact rollers suffer from problems such as wrinkles, dark spots, and vertical streaks in thin substrate coating, which are more or less related to the processing, installation, and thermal deformation of solid rollers. Since thin substrates are generally on the micrometer scale, these problems are easily generated. Air-floating rollers are one approach attempting to solve this problem. While different application scenarios lead to different research focuses on air-floating rollers, the overall situation is similar across industries: ensuring process quality while achieving non-contact transfer of thin substrates. In conclusion, although the application of air-floating rollers in the lithium battery coating industry is not yet widespread and problems such as unstable floating and reduced coating speed exist, its research and development is of great significance for single-sided coating, especially double-sided coating.

[0003] The main problem is that, at a constant flow rate, the velocity of compressed air entering the roller cavity decreases, with the velocity near the inlet being greater than that further away, creating a pressure gradient along the axial airflow direction and gradually decreasing the pressure difference. This leads to two issues between the roller surface and the substrate: irregular wavy patterns appear on the substrate surface; and the air flotation height at the inlet and outlet ends of the substrate is significantly lower than the middle air flotation height along the substrate's conveyor path. Furthermore, existing air flotation rollers require a large amount of space.

[0004] Therefore, there is an urgent need for a small-diameter air flotation roller with stable flow rate and its preparation method. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a small-diameter air flotation roller with stable flow rate and a method for preparing the same, which overcomes or at least partially solves the above problems.

[0006] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0007] According to a first aspect of the present invention, a small-diameter air flotation roller with stable flow rate is provided, comprising: an air flotation roller, a plurality of throttling nozzles, a partition plate, and two sets of pressure regulating valves; the air flotation roller is a hollow cavity structure with open ends, and the inner cavity of the air flotation roller is divided into a middle cavity and a side cavity by the partition plate; a plurality of mounting grooves are arranged in an array at equal intervals along the axial direction and the circumferential direction on the outer side of the inner cavity, and a through hole is provided at the bottom of the mounting groove; each mounting groove is provided with a throttling nozzle, and the ejection direction of the plurality of throttling nozzles distributed at intervals along the circumferential direction intersects with the circumferential direction; the throttling nozzles are connected to the inner cavity through the through hole; wherein the throttling nozzles located at the air inlet and air outlet ends on both sides along the circumferential direction constitute a first nozzle group, and the throttling nozzles located in the middle region constitute a second nozzle group; the first nozzle group is connected to the side cavity, the second nozzle group is connected to the middle cavity, and the two sets of pressure regulating valves are respectively connected to the middle cavity and the side cavity.

[0008] In some embodiments of the present invention, the throttling nozzle includes at least a valve core, a spring, an opening adjustment ring, and a sealing throttling nozzle. The valve core is disposed in the mounting groove, with the bottom of the valve core facing the through hole. The sealing throttling nozzle is fixedly connected to the mounting groove. The opening adjustment ring is screwed onto the side of the sealing throttling nozzle facing the mounting groove. The spring is disposed in the valve core and is a cylindrical spring structure. The upper end of the spring abuts against the inner side of the opening adjustment ring, and the lower end of the spring abuts against the inner side of the valve core.

[0009] According to a second aspect of the present invention, a method for preparing a small-diameter air-float roller with stable flow rate is provided, the method comprising:

[0010] Obtain the initial parameters of the air flotation roller at the air inlet end, wherein the initial parameters include at least the initial flow rate at the air inlet end, the air flotation height of the throttling nozzle, and the inner diameter of the air flotation roller;

[0011] Based on the initial parameters, target parameters for each of the throttling nozzles along the axial direction are determined. The target parameters include the maximum pressure difference between two different throttling nozzles, as well as the gas pressure, average flow velocity, and nozzle flow rate of each throttling nozzle at the nozzle position.

[0012] The target parameters are corrected based on the leakage of airflow at both ends of the air flotation roller, and the back pressure of each throttling nozzle is adjusted based on the corrected target parameters so that the nozzle flow rates of each throttling nozzle located in the same column along the axial direction on the array are the same, thereby obtaining the small-diameter air flotation roller with stable flow rate.

[0013] In some embodiments of the present invention, the method further includes: obtaining the initial flow rate at the air inlet, the inner diameter of the air flotation roller, and the nozzle flow rate of each throttling nozzle, and determining the average flow velocity of each throttling nozzle at the nozzle position based on the initial flow rate at the air inlet, the inner diameter of the air flotation roller, and the nozzle flow rate of each throttling nozzle.

[0014] In some embodiments of the present invention, the method further includes: obtaining the nozzle diameter of each throttling nozzle and the outlet flow velocity of each throttling nozzle, and determining the nozzle flow rate of each throttling nozzle at the nozzle position based on the nozzle diameter and the outlet flow velocity.

[0015] In some embodiments of the present invention, the method further includes: determining the gas pressure at the nozzle position of each of the throttling nozzles based on the average flow velocity, displacement, and orifice diameter at the air inlet end of the air flotation roller.

[0016] In some embodiments of the present invention, the method further includes: acquiring the gas pressure of the two throttling nozzles at the nozzle positions respectively, and determining the maximum pressure difference between the two different throttling nozzles based on the gas pressure difference between the two throttling nozzles.

[0017] In some embodiments of the present invention, adjusting the back pressure of each of the throttling nozzles so that the nozzle flow rates of each of the throttling nozzles located in the same column along the axial direction on the array are the same includes:

[0018] Collect back pressure data for each of the throttling nozzles at different opening degrees;

[0019] Based on the target parameters and back pressure data corresponding to each throttling nozzle, the opening of each throttling nozzle is adjusted so that the nozzle flow rate of each throttling nozzle located in the same column along the axial direction on the array is the same.

[0020] In some embodiments of the present invention, the method further includes, before adjusting the back pressure of each of the throttling nozzles:

[0021] Based on the maximum pressure difference between each of the throttling nozzles, the internal parameters corresponding to each throttling nozzle are determined, and the internal parameters include the stiffness coefficient of the spring in the throttling nozzle;

[0022] The design parameters corresponding to the spring are selected according to the internal parameters, and the design parameters include free height, height under allowable load, and allowable load.

[0023] In some embodiments of the present invention, the correction of the target parameter based on the leakage of airflow at both ends of the air flotation roller includes:

[0024] Obtain the wrap angle and flow coefficient of the throttling nozzles corresponding to the first nozzle group and the second nozzle group;

[0025] The nozzle flow rates of the throttling nozzles corresponding to the first nozzle group and the second nozzle group are calculated based on the wrap angle and flow coefficient, and the leakage of airflow at both ends of the air flotation roller is obtained.

[0026] The target parameters are corrected based on the leakage of airflow at both ends of the air flotation roller.

[0027] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0028] The present invention relates to a flow-stabilized small-diameter air-float roller and its preparation method. The method involves determining target parameters for each throttling nozzle along the axial direction using initial parameters, correcting these target parameters based on the leakage of airflow at both ends of the air-float roller, and adjusting the back pressure of each throttling nozzle based on the corrected target parameters. This ensures that the ejection flow rates of each throttling nozzle located in the same column along the axial direction are identical. The resulting flow-stabilized small-diameter air-float roller provides relatively uniform air-float pressure on the thin substrate, effectively overcoming the problem of unstable floating of the thin substrate when the air-float roller suspends it through the ejected airflow from the throttling nozzles in the prior art, thus improving the coating speed of the thin substrate.

[0029] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a cross-sectional view along the axial direction of the small-diameter air-float roller with stable flow rate described in an embodiment of the present invention;

[0032] Figure 2 This is an isometric view of the air flotation roller with stable flow rate described in an embodiment of the present invention;

[0033] Figure 3 This is a cross-sectional view along the circumferential direction of the small-diameter air flotation roller with stable flow rate described in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of the throttling nozzle described in an embodiment of the present invention;

[0035] Figure 5 A schematic flowchart illustrating a method for preparing a small-diameter air-float roller with stable flow rate, provided in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the principle structure of a small-diameter air flotation roller preparation system with stable flow rate provided in an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Air flotation roller; 2. Throttling nozzle; 3. Baffle plate; 11. Inner cavity; 12. Mounting groove; 13. Through hole; 14. Intermediate cavity; 15. Side cavity; 21. Valve core; 22. Spring; 23. Opening adjustment ring; 24. Sealing throttling nozzle. Detailed Implementation

[0039] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0040] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0041] In the context of this disclosure, when a layer / component is referred to as being "above" another layer / component, that layer / component may be directly above the other layer / component, or there may be an intermediate layer / component between them. Additionally, if a layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component may be "below" the other layer / component. In the context of this disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0042] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0043] like Figure 1-3As shown, the small-diameter air flotation roller of this embodiment includes an air flotation roller 1, multiple throttling nozzles 2, a partition 3, and two sets of pressure regulating valves (not shown). The air flotation roller 1 is a hollow cavity structure with openings at both ends. The inner cavity 11 of the air flotation roller 1 is divided into two cavities by the partition 3, namely a middle cavity 14 and a side cavity 15. Multiple mounting grooves 12 are arranged in an array at equal intervals along the axial and circumferential directions on the outer side of the inner cavity 11. The bottom of the mounting groove 12 is provided with a through hole 13. Each mounting groove 12 is provided with a throttling nozzle. The nozzle 2, and the multiple throttling nozzles 2 distributed at intervals along the circumference, all have their ejection directions intersecting the circumferential direction. The throttling nozzles 2 are connected to the inner cavity 11 through the through hole 13. The throttling nozzles 2 located at the air inlet and air outlet on both sides along the circumferential direction constitute the first nozzle group, and the throttling nozzles 2 located in the middle region constitute the second nozzle group. The first nozzle group is connected to the side cavity 15, and the second nozzle group is connected to the middle cavity 14. The two sets of pressure regulating valves are respectively connected to the middle cavity 14 and the side cavity 15.

[0044] In this embodiment of the invention, the spacing between two adjacent mounting slots 12 along the axial direction or between two adjacent mounting slots 12 along the circumferential direction can be selected according to actual application requirements.

[0045] Combination Figure 4 As shown, in this embodiment of the invention, the throttling nozzle 2 can be a proportional throttling valve, which has the advantages of stable output flow, adjustable flow rate, and high degree of automation.

[0046] The throttling nozzle 2 includes at least a valve core 21, a spring 22, an opening adjustment ring 23, and a sealing throttling nozzle 24. The valve core 21 is disposed within the mounting groove 12, with its bottom facing the through hole 13. The sealing throttling nozzle 24 is fixedly connected to the mounting groove 12, and the opening adjustment ring 23 is screwed onto the side of the sealing throttling nozzle 24 facing the mounting groove 12. The spring 22 is disposed within the valve core 21 and is a cylindrical spring structure. The upper end of the spring 22 abuts against the inner side of the opening adjustment ring 23. The lower end of the spring 22 is held against the inner side of the valve core 21. The opening adjustment ring 23 is used to limit the movement stroke of the spring 22 to control the compression of the spring 22. Since the valve core 21 will move outward along the sealing throttle nozzle 24 (i.e., the opening ejection direction) under the action of airflow, the opening of the throttle nozzle 2 can be adjusted by adjusting the opening adjustment ring 23 in this embodiment of the invention, thereby achieving control of the back pressure of the throttle nozzle 2. The back pressure can be effectively used to eliminate the influence of pressure reduction generated by the airflow along the axial direction of the air float roller 1.

[0047] The small-diameter air-float roller described in this embodiment of the invention can adjust the back pressure of each of the throttling nozzles 2 to make the ejection flow rate of each of the throttling nozzles 2 located in the same column along the axial direction of the array the same. This effectively overcomes the problem that the thin substrate is prone to floating and unstable when the ejected airflow of the air-float roller 1 suspends the thin substrate in the prior art, and improves the coating speed of the thin substrate.

[0048] Based on the above embodiments, this invention also provides a method for preparing a small-diameter air-float roller with stable flow rate, such as... Figure 5 As shown, the method for preparing this small-diameter air-float roller with stable flow includes the following steps:

[0049] S1. Obtain the initial parameters of the air flotation roller 1 at the air inlet end.

[0050] In this embodiment of the invention, the initial parameters include at least the initial flow rate at the air inlet, the air flotation height of the throttling nozzle 2 (i.e., the floating height of the thin substrate), and the inner diameter of the air flotation roller 1; in this embodiment of the invention, the initial parameters refer to data that can be obtained through corresponding detection devices or equipment data.

[0051] In this embodiment of the invention, the initial parameters may also include the nozzle diameter of the throttling nozzle 2, the outlet velocity of the throttling nozzle 2, the air density, the orifice diameter of the air inlet end of the air flotation roller 1, the viscosity coefficient, etc.

[0052] In some applications, the air flotation height at the inlet and outlet ends of the thin substrate may be significantly lower than that at the middle along the circumference of the roller. This is mainly due to the greater flow leakage at the inlet and outlet ends. Therefore, this embodiment of the invention overcomes this problem by adding a throttling nozzle 2 in the circumferential direction. (See reference...) Figure 3 The figure shows a cross-sectional view of the air flotation roller 1 along the circumferential direction. The air flotation roller 1 has a plurality of throttling nozzles 2 spaced apart along the circumferential direction, and the ejection direction of the plurality of throttling nozzles 2 spaced apart along the circumferential direction intersects with the circumferential direction. For example, in the embodiment of the present invention, a plurality of throttling nozzles 2 can be spaced apart along the circumferential direction at both ends of the air flotation roller 1 (i.e., the position of the throttling nozzle 2 near the air inlet end and the position of the throttling nozzle 2 furthest from the air inlet end).

[0053] It should be noted that, in order to maintain a stable air source, in this embodiment of the invention, the air flotation roller 1 can also be equipped with two sets of pressure regulating valves. One set of the two sets of pressure regulating valves controls the air flow rate in the middle layer along the circumferential direction, and the other set controls the air flow rate at the inlet and outlet ends along the circumferential direction. The pressure regulating valve set at the inlet end is adjusted according to the initial flow rate at the inlet end, and the pressure at the inlet end is kept constant by the pressure regulating valve, thereby providing an auxiliary effect for stabilizing the floating thin substrate.

[0054] S2. Based on the initial parameters, determine the target parameters of each of the throttling nozzles 2 along the axial direction.

[0055] In this embodiment of the invention, the target parameters include, for example, the maximum pressure difference between the two different throttling nozzles 2, and the gas pressure, average flow rate, and nozzle flow rate of each of the throttling nozzles 2 at the nozzle position.

[0056] In this embodiment of the invention, the initial flow rate at the air inlet, the inner diameter of the air flotation roller 1, and the nozzle flow rate of each throttling nozzle 2 are obtained, and the average flow velocity of each throttling nozzle 2 at the nozzle position is determined based on the initial flow rate at the air inlet, the inner diameter of the air flotation roller 1, and the nozzle flow rate of each throttling nozzle 2.

[0057] Specifically, in this embodiment of the invention, the average flow velocity at the nozzle position of any nth section of the air flotation roller 1 along the axial direction at the throttling nozzle 2 is calculated using the following formula 1:

[0058]

[0059] In the formula, u n Q0 is the average flow velocity of the throttling nozzle 2 at any nth section along the axial direction of the air flotation roller 1 at the nozzle position; Q0 is the initial flow rate at the inlet end; Qn is the average flow velocity of the throttling nozzle 2 at any nth section along the axial direction of the air flotation roller 1 ... m D1 is the nozzle flow rate of the throttling nozzle 2 in the m-th section; D1 is the inner diameter of the air flotation roller 1; m is the number of throttling nozzles 2 along the axial direction, and m and n are both positive integers.

[0060] Optionally, in this embodiment of the invention, the nozzle diameter and outlet velocity of each throttling nozzle 2 are obtained, and the nozzle flow rate of each throttling nozzle 2 at the nozzle position is determined based on the nozzle diameter and outlet velocity.

[0061] Specifically, in this embodiment of the invention, the nozzle flow rate of the throttling nozzle 2 in the m-th section is calculated using the following formula 2:

[0062]

[0063] In the formula, a represents the number of throttling nozzles 2 in the circumferential direction (i.e., the number of throttling nozzles 2 in the first nozzle group or the number of throttling nozzles 2 in the second nozzle group); d 节 The nozzle diameter of throttling nozzle 2; u 喷 The outlet flow rate of the throttling nozzle 2 is .

[0064] Assuming the thin substrate is in equilibrium, and based on the principle that buoyancy and tension are equal, due to the outlet flow velocity u of the throttling nozzle 2... 喷 If the value is fixed after installation, then the nozzle flow rate Q of the m-th throttling nozzle 2 is... m It is also a constant value, calculated based on the aforementioned formula.

[0065] Accordingly, when n=1, we can obtain the following formula 3 to calculate u1:

[0066]

[0067] Similarly, the average flow velocity u corresponding to each throttling nozzle 2 can be obtained according to the simplified formula.

[0068] Optionally, in this embodiment of the invention, the gas pressure at the nozzle position of each throttling nozzle 2 is determined based on the average flow velocity and displacement at each throttling nozzle 2 and the orifice diameter at the air inlet end of the air flotation roller 1.

[0069] Because the throttling nozzle 2 near the inlet exhausts first, the airflow velocity along the axial direction of the air flotation roller 1 gradually decreases. A pressure gradient exists along a unit length (the axial distance between two adjacent throttling nozzles 2). The pressure gradient ξ refers to the pressure change per unit distance along the fluid flow direction, and can be expressed in the form of increment ΔP / ΔL or differential dp / dl. By determining the relationship between the gas pressure P and the displacement L along the axial direction, it is convenient to calculate the gas pressure at each throttling nozzle 2 position and the pressure difference per unit length.

[0070] Specifically, the Reynolds number of the fluid is calculated using the following formula 4 in the embodiments of the present invention:

[0071]

[0072] In the formula, ρ is the air density, kg / m³ 3 u is the average flow velocity, m / s; d is the orifice diameter at the air inlet of the air flotation roller 1, m; η is the viscosity coefficient, Pa·s.

[0073] The friction loss of fluid in a straight pipe, caused by internal friction, is calculated using the following formula 5:

[0074]

[0075] In the formula, ΔPf is the friction loss along the line, Pa; λ is the coefficient of friction; L is the displacement, mm;

[0076] For example, when the initial flow rate Q0 = 1400 L / min, the maximum average flow velocity u0 = 16.6 m / s, and the fluid density ρ = 1.29 kg / m³ are obtained... 3 The design value of d is 0.042m, and at 60 degrees Celsius, η = 2 × 10 -5 Pa·s, R is calculated eThe coefficient is greater than 4000, therefore the airflow state inside the air flotation roller 1 is turbulent. The friction coefficient of turbulence is complex, and the friction coefficient λ is related to ε / d and R... e There is a functional relationship between them, and the value of λ = 2.4 is determined by looking up a table (Moody diagram).

[0077] According to the relevant definition of pressure gradient, the pressure gradient relationship is shown in Formula 6. When the axial spacing of the throttling nozzle 2 is taken as the research object, Formula 7 is obtained when L=ΔL. Formula 8 is obtained by differentiating Formula 7.

[0078]

[0079] In the formula, ξ is the pressure gradient; P is the gas pressure of the throttling nozzle 2 at the nozzle position; and C is a constant.

[0080] Therefore, in this embodiment of the invention, formula 8 is used to determine the average flow velocity u of the throttling nozzle 2 at the nth section. n The displacement L and the orifice diameter d at the air inlet end of the air flotation roller 1 are used to determine the gas pressure P of the throttling nozzle 2 at the nozzle position described in Section n. n .

[0081] In this embodiment of the invention, the gas pressure at the nozzle position of each of the two throttling nozzles 2 is obtained. Based on the difference in gas pressure between the two throttling nozzles 2, the maximum pressure difference between the two different throttling nozzles 2 is determined. Therefore, the maximum pressure difference ΔP between the throttling nozzle 2 in the nth section and the throttling nozzle 2 in the mth section is... m-n Then we have △P m-n =P m -P n The gas pressure P at the throttling nozzle 2 in the nth section was calculated separately. n And the gas pressure P at the throttling nozzle 2 in section m. m The maximum pressure difference ΔP between the two is obtained. m-n .

[0082] For example, given the design parameters D1 = 42 mm, L1 = 17 mm, average flow velocity U1 = 91.2 m / s, and other parameters: friction coefficient λ = 2.4, air density ρ = 1.2 kg / m³ 3 The gas pressure P1 is calculated to be 4847.8 Pa.

[0083] Given design parameters D1 = 42 mm, L m =557mm, calculation parameter U m =69.3 m / s, other parameters: friction coefficient λ = 2.4, air density ρ = 1.2 kg / m³ 3 Find P m =91,713.8 Pa.

[0084] Then we have △P m-n =P m -P n =0.09MPa.

[0085] S3. The target parameters are corrected according to the leakage of airflow at both ends of the air flotation roller 1, and the back pressure of each of the throttling nozzles 2 is adjusted based on the corrected target parameters so that the nozzle flow rates of each of the throttling nozzles 2 located in the same column along the axial direction on the array are the same, thereby obtaining the small-diameter air flotation roller with stable flow rate.

[0086] The present invention embodiment corrects the target parameters based on the leakage of airflow at both ends of the air-float roller 1, including: obtaining the wrap angle and flow coefficient of the throttling nozzle 2 corresponding to the first nozzle group and the second nozzle group; calculating the nozzle flow rate of the throttling nozzle 2 corresponding to the first nozzle group and the second nozzle group based on the wrap angle and flow coefficient, and obtaining the leakage of airflow at both ends of the air-float roller 1; and correcting the target parameters based on the leakage of airflow at both ends of the air-float roller 1. Specifically, the airflow forms buoyancy force in the direction perpendicular to the thin substrate, and the component force along the tangent of the thin substrate and opposite to the belt direction is the smoothing force of the thin substrate. Assuming that the tension T of the thin substrate itself is stable, the air-float height h is consistent, and gravity is ignored, a differential wrap angle dβ is intercepted in the circumferential direction of the thin substrate. The thin substrate corresponding to dβ is approximately a plane. It is known that there is an angle θ between the throttling nozzle 2 and the thin substrate, where θ is the buoyancy angle. Assuming that the thin substrate is a "rigid body", according to theoretical fluid mechanics, we obtain:

[0087]

[0088] In the formula, Q is the ejection flow rate corresponding to the nozzle, and ω is the flow coefficient.

[0089] If we define the flow coefficient Then we have:

[0090]

[0091] Where C is a constant.

[0092] For the throttling nozzle 2 of the second nozzle group (i.e., the middle region), its wrap angle is β1. For the throttling nozzle 2 of the first nozzle group (i.e., the inlet and outlet ends), its wrap angle is β2. Then β = β1 + 2β2. Substituting into formula 10, we can obtain the nozzle flow rates Q1 and Q2 of the throttling nozzle 2 corresponding to the first and second nozzle groups. According to the continuity equation Q_total = Q_part, the flow rate calculation at both ends should satisfy the following relationship: Q1 = Q2 + Q_leak, where the leakage amount Q_leak = uWh, and u is the average flow velocity in the width W direction. In this embodiment of the invention, the air flow rate (i.e., the average flow velocity u in the target parameter) of the first nozzle group and the second nozzle group is controlled by two sets of control valves respectively. The air float height of the throttling nozzle 2 can be ensured to be consistent by increasing the leakage amount of the airflow at both ends of the air float roller 1.

[0093] The embodiment of the present invention describes adjusting the back pressure of each of the throttling nozzles 2 based on the corrected target parameters to make the nozzle flow rate of each of the throttling nozzles 2 located in the same column along the axial direction of the array the same, which includes: collecting back pressure data corresponding to each of the throttling nozzles 2 at different opening degrees; and adjusting the opening degree of each of the throttling nozzles 2 according to the target parameters and back pressure data corresponding to each of the throttling nozzles 2 to make the nozzle flow rate of each of the throttling nozzles 2 located in the same column along the axial direction of the array the same.

[0094] In this embodiment of the invention, the compression of the spring 22 can be adjusted by adjusting the screw position of the opening adjustment ring 23, thereby adjusting the opening of each of the throttling nozzles 2, and thus adjusting the back pressure of each of the throttling nozzles 2, eliminating the influence of pressure reduction generated by the airflow along the axial direction of the air flotation roller 1, and stabilizing the outlet flow rate.

[0095] Before adjusting the back pressure of each of the throttling nozzles 2, the embodiment of the present invention further includes: determining the internal parameters corresponding to each of the throttling nozzles 2 according to the maximum pressure difference between each of the throttling nozzles 2, wherein the internal parameters include the stiffness coefficient of the spring 22 in the throttling nozzle 2; and selecting the design parameters corresponding to the spring 22 according to the internal parameters, wherein the design parameters include the free height, the height under allowable load, and the allowable load.

[0096] Specifically, in order to make the flow rates of each of the throttling nozzles 2 the same, this embodiment of the invention first needs to determine the maximum pressure difference between each of the throttling nozzles 2 (the pressure difference is the largest between the first section and the last section), so that the internal parameters corresponding to each of the throttling nozzles 2 can be determined, and the opening adjustment of the throttling nozzles 2 can be avoided from exceeding their design values.

[0097] In this embodiment of the invention, the stiffness coefficient k of the spring 22 in the throttling nozzle 2 is determined by the following formula 11:

[0098]

[0099] In the formula, ΔP m1 denoted by , where is the pressure difference between the throttling nozzle 2 in section m and the throttling nozzle 2 in section 1, and x is the rated compression.

[0100] When x is 7mm, d 节 It is 7mm, ΔP m1 When the pressure is 0.09 MPa, the stiffness coefficient k of the spring 22 in the throttling nozzle 2 can be calculated to be 0.495 N / mm. The selected spring 22 model and parameters are shown in Table 1 below for reference.

[0101] Table 1. Spring 22 Model and Parameters

[0102]

[0103] The method for preparing a small-diameter air-float roller with stable flow rate according to the embodiments of the present invention determines the target parameters of each of the throttling nozzles 2 along the axial direction by obtaining initial parameters, then corrects the target parameters according to the leakage of airflow at both ends of the air-float roller 1, and adjusts the back pressure of each of the throttling nozzles 2 according to the corrected target parameters, so that the nozzle flow rate of each of the throttling nozzles 2 located in the same column along the axial direction on the array is the same. The resulting small-diameter air-float roller with stable flow rate also has a more uniform air-float pressure on the thin substrate, which effectively overcomes the problem of unstable floating when the air-float roller 1 suspends the thin substrate in the prior art, and improves the coating speed of the thin substrate. At the same time, the air-float roller 1 has multiple throttling nozzles 2 distributed at intervals along the circumferential direction, and the ejection direction of the multiple throttling nozzles 2 distributed at intervals along the circumferential direction intersects with the circumferential direction, which occupies less installation space and saves internal space, thus realizing the preparation of a small-diameter air-float roller.

[0104] Based on the above embodiments, as a supplement to the above... Figure 5 The present invention provides an embodiment of a small-diameter air flotation roller preparation system with stable flow rate, which is similar to the method shown. Figure 5 Corresponding to the method embodiments shown, this system can be specifically applied to various electronic devices. (See attached document.) Figure 6 As shown, the flow-stabilized small-diameter air flotation roller preparation system includes:

[0105] The data acquisition module 100 is used to acquire the initial parameters of the air flotation roller 1 at the air inlet end, wherein the initial parameters include at least the initial flow rate at the air inlet end, the air flotation height of the throttling nozzle 2, and the inner diameter of the air flotation roller 1.

[0106] The first processing module 200 is used to determine the target parameters of each of the throttling nozzles 2 along the axial direction based on the initial parameters. The target parameters include the maximum pressure difference between two different throttling nozzles 2, as well as the gas pressure, average flow velocity, and nozzle flow rate of each throttling nozzle 2 at the nozzle position.

[0107] The second processing module 300 is used to correct the target parameters according to the leakage of airflow at both ends of the air flotation roller 1, and adjust the back pressure of each of the throttling nozzles 2 based on the corrected target parameters, so that the nozzle flow of each of the throttling nozzles 2 is the same, thereby obtaining the small-diameter air flotation roller with stable flow.

[0108] The flow-stable small-diameter air-float roller preparation system described in this embodiment can perform the flow-stable small-diameter air-float roller preparation method provided in the above embodiments. The flow-stable small-diameter air-float roller preparation system has the corresponding functional steps and beneficial effects of the flow-stable small-diameter air-float roller preparation method described in the above embodiments. For details, please refer to the embodiments of the flow-stable small-diameter air-float roller preparation method described above. The embodiments of this invention will not be repeated here.

[0109] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0110] Similarly, it should be understood that, in order to streamline this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0111] It should be noted that the above embodiments are illustrative of the invention and not restrictive of the invention, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims.

Claims

1. A small-diameter air flotation roller with stable flow rate, characterized in that, include: Air flotation roller, multiple throttling nozzles, baffles, and two sets of pressure regulating valves; The air flotation roller is a hollow cavity structure with openings at both ends. The inner cavity of the air flotation roller is divided into an intermediate cavity and a side cavity by the partition plate. Multiple mounting slots are arranged in an array at equal intervals along the axial and circumferential directions on the outer side of the inner cavity. A through hole is provided at the bottom of the mounting slot. The throttling nozzle is provided in each mounting slot. The ejection direction of the multiple throttling nozzles distributed at intervals along the circumferential direction intersects with the circumferential direction. The throttling nozzle is connected to the inner cavity through the through hole. The throttling nozzles located at the air inlet and outlet on both sides along the circumferential direction constitute the first nozzle group, and the throttling nozzles located in the middle region constitute the second nozzle group. The first nozzle group is connected to the side cavity, and the second nozzle group is connected to the middle cavity. The two sets of pressure regulating valves are respectively connected to the middle cavity and the side cavity.

2. The small-diameter air-float roller with stable flow rate according to claim 1, characterized in that: The throttling nozzle includes at least a valve core, a spring, an opening adjustment ring, and a sealing throttling nozzle. The valve core is disposed in the mounting groove, with its bottom facing the through hole. The sealing throttling nozzle is fixedly connected to the mounting groove, and the opening adjustment ring is screwed onto the side of the sealing throttling nozzle facing the mounting groove. The spring is disposed inside the valve core and is a cylindrical spring structure. The upper end of the spring abuts against the inner side of the opening adjustment ring, and the lower end of the spring abuts against the inner side of the valve core.

3. A method for preparing a small-diameter air-float roller with stable flow rate, applied to the small-diameter air-float roller with stable flow rate as described in any one of claims 1-2, characterized in that, The method for preparing the small-diameter air flotation roller with stable flow includes: Obtain the initial parameters of the air flotation roller at the air inlet end, wherein the initial parameters include at least the initial flow rate at the air inlet end, the air flotation height of the throttling nozzle, and the inner diameter of the air flotation roller; Based on the initial parameters, target parameters for each of the throttling nozzles along the axial direction are determined. The target parameters include the maximum pressure difference between two different throttling nozzles, as well as the gas pressure, average flow velocity, and nozzle flow rate of each throttling nozzle at the nozzle position. The target parameters are corrected based on the leakage of airflow at both ends of the air flotation roller, and the back pressure of each throttling nozzle is adjusted based on the corrected target parameters so that the nozzle flow rates of each throttling nozzle located in the same column along the axial direction on the array are the same, thereby obtaining the small-diameter air flotation roller with stable flow rate.

4. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 3, characterized in that, The method further includes: obtaining the initial flow rate at the air inlet, the inner diameter of the air flotation roller, and the nozzle flow rate of each throttling nozzle, and determining the average flow velocity of each throttling nozzle at the nozzle position based on the initial flow rate at the air inlet, the inner diameter of the air flotation roller, and the nozzle flow rate of each throttling nozzle.

5. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 3, characterized in that, The method further includes: obtaining the nozzle diameter and outlet velocity of each throttling nozzle, and determining the nozzle flow rate of each throttling nozzle at the nozzle position based on the nozzle diameter and outlet velocity.

6. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 3, characterized in that, The method further includes: determining the gas pressure at the nozzle position of each throttling nozzle based on the average flow velocity, displacement, and orifice diameter at the air inlet end of the air flotation roller.

7. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 3, characterized in that, The method further includes: acquiring the gas pressure at the nozzle position of the two throttling nozzles respectively, and determining the maximum pressure difference between the two different throttling nozzles based on the gas pressure difference between the two throttling nozzles.

8. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 7, characterized in that, The step of adjusting the back pressure of each of the throttling nozzles to make the nozzle flow rates of each of the throttling nozzles located in the same column along the axial direction of the array the same includes: Collect back pressure data for each of the throttling nozzles at different opening degrees; Based on the target parameters and back pressure data corresponding to each throttling nozzle, the opening of each throttling nozzle is adjusted so that the nozzle flow rate of each throttling nozzle located in the same column along the axial direction on the array is the same.

9. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 8, characterized in that, Before adjusting the back pressure of each of the throttling nozzles, the method further includes: Based on the maximum pressure difference between each of the throttling nozzles, the internal parameters corresponding to each throttling nozzle are determined, and the internal parameters include the stiffness coefficient of the spring in the throttling nozzle; The design parameters corresponding to the spring are selected according to the internal parameters, and the design parameters include free height, height under allowable load, and allowable load.

10. The method for preparing a small-diameter air-float roller with stable flow rate according to claim 3, characterized in that, The step of correcting the target parameter based on the leakage of airflow at both ends of the air flotation roller includes: Obtain the wrap angle and flow coefficient of the throttling nozzles corresponding to the first nozzle group and the second nozzle group; The nozzle flow rates of the throttling nozzles corresponding to the first nozzle group and the second nozzle group are calculated based on the wrap angle and flow coefficient, and the leakage of airflow at both ends of the air flotation roller is obtained. The target parameters are corrected based on the leakage of airflow at both ends of the air flotation roller.

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