Sand-proof and dust-proof method for electrolytic cell based on Coanda effect

Abstract

The invention discloses an electrolytic cell sand and dust prevention method based on the Coanda effect. Comprising the following steps: S1, forming a surrounding type dust cover structure which is in flexible contact with the electrolytic cell or keeps a non-contact gap with the electrolytic cell on the periphery of the full-bearing type movable bracket; s2, airflow sealing is conducted, specifically, an inner side cavity surrounded by the dustproof cover structure is continuously inflated with gas, and external sand and dust are separated through the dustproof cover structure; and S3, Coanda wall attachment acceleration is conducted, gas laminar flow is guided to a continuous variable-curvature Coanda curved surface, the gradual change curved surface of the Coanda curved surface is used for enabling gas to generate a wall attachment effect, the gas flow speed is increased, and a jet flow air curtain is formed. A continuous variable-curvature Coanda curved surface is adopted, the airflow speed is increased through the wall attachment effect, a laminar flow air curtain is formed, and curvature-flow velocity coupling optimization is formed. Compressed air is injected through the narrow slit nozzle, ambient air is pried to form a large-flow air curtain, the actually measured air curtain coverage area is 3.2 times that of a traditional flow guide plate, and the unit energy consumption is reduced by 57%.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic cell auxiliary devices, and particularly relates to a method for preventing sand and dust in an electrolytic cell based on the Coanda effect. Background Art

[0002] As one of the key paths for clean energy production, the filter press electrolytic cell, as an important technical branch in the field of hydrogen production by water electrolysis, the improvement and structural optimization of its supporting equipment have always been the focus of technological innovation.

[0003] During the operation of a filter press water electrolytic cell, due to the long-term action of gravity on the electrode plates, phenomena such as the middle section sinking and the left and right end plates turning outwards in a V shape occur during use. The electrode plates displace vertically due to gravity, and then the electrode plates sink, which affects the uniformity of the inter-pole distance inside the electrolytic cell and reduces the electrolysis efficiency.

[0004] Our company's prior application for a utility model (ZL202322792604.1) discloses an electrolytic cell support unit and a fully load-bearing mobile bracket composed of the same. The electrolytic cell support unit includes a top support device, a support device, and a sliding device. An adjusting bolt is provided at the connection between the support device and the sliding device. The inclination angle and height of the top support device can be adjusted through the adjusting bolt. The fully load-bearing mobile bracket includes a plurality of the above-mentioned electrolytic cell support units. The electrolytic cell support units are placed on the foundation or steel profiles, and insulating supporting wheels are placed under the electrode plates of the electrolytic cell.

[0005] This utility model solves the problems of sinking, sliding, and end plate turning outwards of the electrolytic cell electrode plates caused by gravity. At the same time, as the working temperature of the electrolytic cell body changes, the body will expand and contract thermally and move radially. Therefore, the above support unit has the function of radial movement. Through the sliding device, the electrolytic cell support unit can generate a certain sliding margin by itself, adapt to the changing environment by itself, avoid rigid deformation, and at the same time, through the tooth grooves, the gasket between the electrode plates can be squeezed into the tooth grooves when it expands and deforms thermally, and there is room for deformation, avoiding excessive extrusion of the gasket on the electrode plates.

[0006] Many hydrogen production projects are built in sandy environments. If the electrolytic cell encounters interference from sand and dust during operation, the support unit is directly exposed to this environment. Just relying on a ceiling cannot completely and effectively shield the electrolytic cell body. Especially, sand or large particulate dust such as stones will be unobstructedly drawn into the support unit. Over time, a large amount of pollutants will accumulate at the rollers where the support unit moves radially, causing the support unit to malfunction. During operation, it cannot continuously provide a uniform supporting force for the electrolytic cell, and thus cannot solve the problem of support misalignment caused by the thermal expansion of the cell body during the use of the electrolytic cell, increasing the risk of liquid leakage at both ends of the electrolytic cell especially.

[0007] In view of the above, it is necessary to propose a method for preventing sand and dust in an electrolytic cell based on the Coanda effect to solve the above problems. Summary of the Invention

[0008] The object of the present invention is to overcome the defects existing in the prior art and provide a method for preventing sand and dust in an electrolytic cell based on the Coanda effect.

[0009] To achieve the above object, the technical solution of the present invention is as follows: A method for preventing sand and dust in an electrolytic cell based on the Coanda Effect includes the following steps: S1: Form a dust-proof cover structure that is in a surrounding type and is in flexible contact with or maintains a non-contact gap with the electrolytic cell on the periphery of the full-load mobile bracket. The dust-proof cover structure forms a semi-closed protection structure between the foundation and the electrolytic cell. S2: Airflow sealing. Continuously fill the inner chamber surrounded by the dust-proof cover structure with gas, or form gas flow in the dust-proof cover structure itself and generate an air curtain by spraying from a specific part, so that the dust-proof cover structure separates external sand and dust. S3: Coanda wall attachment acceleration. Guide the gas laminar flow to a continuously variable curvature Coanda surface, and use the gradually changing surface of the Coanda surface to cause the gas to produce a wall attachment effect, so that the gas flow rate is increased to form a jet air curtain.

[0010] Further, the dust-proof cover structure at least includes a vertical enclosure wall provided on the side of the full-load mobile bracket. The bottom of the vertical enclosure wall is connected to the foundation, and the top is in flexible contact with the electrolytic cell or forms a non-contact gap.

[0011] Further, the dust-proof cover structure is provided with a through ventilation opening formed in the preset gas outflow direction, and the through ventilation opening is provided with a gas jet outlet at least at the gas outflow end.

[0012] Further, the through ventilation opening forms a gas suction port at one end far from the gas jet outlet. The dust-proof cover structure includes vertical enclosure walls provided on both sides of the through ventilation opening. The end faces of the vertical enclosure walls close to each other form a Coanda surface. The Coanda surface diagram includes a curved surface convex portion formed on the side far from the gas jet outlet, and the curved surface convex portion gradually transitions to the gas jet outlet side to form an inclined surface. The opening direction formed by the two inclined surfaces faces the gas jet outlet.

[0013] Further, the Coanda surface adopts a continuously variable curvature design, and the radius of curvature R gradually changes from 50 mm to 200 mm.

[0014] Further, a cavity portion is provided inside the vertical enclosure. The cavity portion is provided with a slit-shaped air flow jet port for gas to flow out along the tangent direction on the front side of the curved surface convex portion.

[0015] Further, the dust-proof cover structure includes an ion wind generation module, and the ion wind generation module includes an electrode array. The electrode array is provided with an emitter and a collector, and the ionization region is arranged between the emitter and the collector. The emitter includes tungsten needle electrodes arranged in front of the curved convex part; the collection region is a conductive silicon carbide layer plated on the surface of the convex part of the Coanda surface, and an electric field gradient is formed by grounding it; the electrode spacing in the ionization region is 20-30 mm, the electric field strength E = 7.5 kV / cm, and corona discharge induces the formation of ion wind. The ion wind airflow passes through the Coanda surface and is further accelerated by the pressure gradient generated by its curvature.

[0016] Further, a negative pressure pipe is provided on the vertical enclosure wall near the full-bearing mobile bracket side. The vertical enclosure walls symmetrically arranged on both sides form a throat section at the curved convex part. A reducing pipe is formed in the front of the throat section, and an expanding pipe is formed in the rear. One end of the negative pressure pipe is connected to the throat section, and the other end is connected to the inner side of the semi-closed protection structure.

[0017] Further, the dust-proof cover structure is made of transparent and visualizable material.

[0018] Further, the dust-proof cover structure is made of material resistant to alkali liquor corrosion.

[0019] The advantages and beneficial effects of the present invention are as follows: 1. For an electrolytic cell sand and dust prevention method based on the Coanda Effect of the present invention, a flexible connection or non-contact gap using brushes is adopted between the vertical enclosure and the electrolytic cell, allowing the electrolytic cell to have a telescopic displacement of ±5 mm level due to temperature changes, alleviating the risk of support misalignment caused by thermal stress. The upper and lower rows of brushes are staggered and fitted to form a progressive interception layer. Experimental data shows that the interception rate of 1 mm sand particles reaches 100%, and the blocking efficiency of 0.1 mm fine dust is 98.7%. At the same time, the air gap heat dissipation channel is maintained, and the temperature rise in the inner cavity is controlled within <3°C.

[0020] 2. A continuously variable curvature Coanda surface is adopted, and the air flow velocity is increased through the wall attachment effect to form a laminar air curtain, achieving the optimization of curvature-flow velocity coupling. Compressed air is injected through a narrow slit nozzle to pry the ambient air to form a large-flow air curtain. The measured air curtain coverage area is 3.2 times that of the traditional deflector, and the unit energy consumption is reduced by 57%.

[0021] 3. The ion wind-Coanda composite enhancement mechanism, corona discharge induces air flow: the tungsten needle electrode array generates ion wind under the electric field, with an initial wind speed of 4.5 m / s, which is accelerated by the Coanda surface and the flow rate is increased several times.

[0022] 4. Negative pressure self-driven circulation system, utilizing the Venturi effect: The throat section (cross-sectional contraction ratio of 1:3.2) generates a local negative pressure of -1.2 kPa, automatically extracting the gas inside the protective cover through the negative pressure pipe, achieving a ventilation rate of 12 times per hour with no additional power consumption, and saving 68% energy compared to active air supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a schematic structural diagram of an electrolytic cell sand and dust prevention and control device based on the Coanda effect of the present invention; Figure 2 FIG. is an exploded view of an electrolytic cell sand and dust prevention and control device based on the Coanda effect of the present invention; Figure 3 FIG. is a schematic longitudinal sectional view of an electrolytic cell sand and dust prevention and control device based on the Coanda effect of the present invention; Figure 4 FIG. is of the present invention Figure 3 Schematic structural diagram of the A-A cross-section; Figure 5 FIG. is a schematic structural diagram of Embodiment III of the present invention; Figure 6 FIG. is a schematic structural diagram of Embodiment IV of the present invention; Figure 7 FIG. is a schematic structural diagram of Embodiment V of the present invention; Figure 8 FIG. is a schematic structural diagram of Embodiment VI of the present invention; Figure 9 FIG. is a schematic structural diagram of Embodiment VII of the present invention; In the figures: 1. Dust-proof cover structure; 2. Support unit; 3. Vertical enclosure wall; 4. Foundation; 5. Electrolytic cell; 6. Flexible connection; 7. Clearance distance; 8. Brush structure; 9. Lower row of brushes; 10. Upper row of brushes; 11. Non-contact clearance; 12. Displacement chamber; 13. Compressed air supply pipe; 14. Air curtain; 15. Through ventilation opening; 16. Gas jet outlet; 17. Cavity part; 18. Coanda surface; 19. Gas suction inlet; 20. Curved convex part; 21. Inclined plane; 22. Airflow nozzle; 23. Through hole; 24. Ion wind generation module; 25. Electrode array; 26. Emitter; 27. Collector; 28. Ionization region; 29. Tungsten needle electrode; 30. Negative pressure pipe; 31. Throat section; 32. Converging pipe; 33. Diverging pipe; 34. Electrically carbonized silicon layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following describes the specific embodiments of the present invention in further detail in conjunction with the drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention. Embodiment I:

[0025] A method for preventing sand and dust in an electrolytic cell based on the Coanda Effect, such as Figure 1 As shown, a dust cover structure 1 is formed on the periphery of the full-load movable bracket, which is in surrounding contact with the electrolytic cell 5 flexibly or maintains a non-contact gap 11, and the dust cover structure 1 forms a semi-enclosed protective structure between the foundation 4 and the electrolytic cell 5. In actual use, the full-load movable bracket is arranged in the form of, the electrolytic cell 5 is set on the foundation or steel, taking the steel as the setting foundation 4 of the electrolytic cell 5 as an example, a plurality of support units 2 of the electrolytic cell 5 are arranged in a line on the steel, and the rolling rod at the bottom can be used to form rolling, so as to deal with the additional stress on the gasket when the cell body of the electrolytic cell 5 expands and contracts due to temperature changes, causing a slight displacement of the electrolytic cell 5. It can be understood that the full-load movable bracket is arranged at the lower part of the electrolytic cell 5 along the length direction of the electrolytic cell 5.

[0026] However, many hydrogen production projects are built in a sandy environment. If the electrolyzer 5 is disturbed by sand during operation, the support unit 2 is directly exposed to this environment. A roof alone cannot completely and effectively shield the electrolyzer 5 body, especially sand or large dust particles such as gravel will be unobstructed and drawn into the support unit 2. As time accumulates, a large amount of pollutants accumulate at the rollers where the support unit 2 moves radially, causing the support unit 2 to be unable to work normally. The operation process cannot continuously provide uniform support for the electrolyzer 5, and it is also impossible to solve the support misalignment problem caused by the thermal expansion of the tank body during the use of the electrolyzer 5, increasing the risk of leakage of the electrolyzer 5, especially at both ends. In this embodiment, a semi-enclosed protective structure is set between the foundation 4-steel and the electrolyzer 5.

[0027] Specifically, Figure 1 , 2As shown in FIG. 3 , a dust cover structure 1 consisting of enclosures can be set on both sides of a foundation based on steel sections 4, wherein the dust cover structure 1 includes at least a vertical enclosure wall 3 arranged on the side of a fully load-bearing mobile bracket, wherein the bottom of the vertical enclosure wall 3 is connected to the foundation 4, and the top is in flexible contact with the electrolytic cell 5 or forms a non-contact gap 11. It can be understood that the vertical enclosure wall 3 can surround the periphery of the full-load-bearing mobile bracket formed by the support unit 2, and the bottom of the vertical enclosure wall 3 is connected to the steel section, so that the bottom of the dust cover structure 1 is sealed. Since the operating temperature of the electrolytic cell 5 during operation is about 60-100°C, the top of the vertical enclosure wall 3 should not be directly sealed on the surface of the electrolytic cell 5, and considering first, the heat dissipation of the surface of the electrolytic cell 5; second, the expansion and contraction changes of the electrolytic cell 5 during operation; third, there will be concave and convex parts on the surface of the electrolytic cell 5 with irregular shapes; so the top of the vertical enclosure wall 3 should not establish a sealed connection with the surface of the electrolytic cell 5 to form a shield; a preferred implementation method in this embodiment is to establish a flexible connection between the top of the vertical enclosure wall 3 and the electrolytic cell 5, and specifically, a gap distance 7 is set between the upper edge of the vertical enclosure wall 3 and the surface of the electrolytic cell 5, and the flexible connection 6 is set in the gap distance 7.

[0028] Specifically, Figure 4 As shown, the flexible connection 6 can be a brush structure 8 arranged on the upper edge of the vertical enclosure wall 3. The brush structure 8 is provided at a gap distance 7 between the vertical enclosure wall 3 and the electrolytic cell 5 to provide a good blocking effect on sand and dust, especially large particles of sand and dust.

[0029] As an improvement, the brush structure 8 may include a lower row of brushes 9 and an upper row of brushes 10. When set, the lower row of brushes 9 is set on the vertical enclosure wall 3, and the upper row of brushes 10 is set on the surface of the electrolytic cell 5, and the upper row of brushes 10 and the lower row of brushes 9 are set sideways in contact with each other, and the brushes are used to block the gap distance 7 to form a barrier to sand and dust; its advantage is that it can not only meet the slight expansion and contraction deformation of the electrolytic cell 5, but also have a good air permeability and heat dissipation effect, avoiding heat accumulation and temperature rise on the inner side of the dust cover structure 1; it can be understood that the lower row of brushes 9 and the upper row of brushes 10 are arranged in at least one row; and, in order to improve the dust blocking effect of the brush structure 8, the lower row of brushes 9 and the upper row of brushes 10 can be arranged in multiple rows, and each row of the lower row of brushes 9 and the upper row of brushes 10 should be staggered. Embodiment 2:

[0030] In a specific implementation, the protective cover structure at least includes a vertical enclosure wall 3 arranged on the side of the full-length load-bearing mobile bracket. The shape of the vertical enclosure wall 3 is not limited, and it can be a rectangle to wrap and protect the support unit 2; multiple vertical enclosure walls 3 are connected to form a surrounding enclosure to separate the full-length load-bearing mobile bracket from the external space, thereby shielding against sand and dust.

[0031] Preferably, the material for manufacturing the protective cover structure should be resistant to alkali solution corrosion. Since the electrolytic cell 5 is filled with alkaline electrolyte, certain requirements are imposed on the alkali solution corrosion resistance of the protective cover structure. In actual use, materials such as polycarbonate (PC), polymethyl methacrylate (acrylic), or plexiglass, which are resistant to alkali, can be used.

[0032] Preferably, the dust-proof cover structure 1 is made of a transparent and visualizable material. For example, the protective cover structure made of transparent acrylic forms a transparent and visualizable enclosure, which allows operators to directly observe the state of the full-load mobile bracket inside from the outside and also facilitates the observation of the surface of the electrolytic cell 5, thus eliminating blind spots for equipment observation. Embodiment Three:

[0033] As another implementation method, on the basis of setting the gap distance 7 in the previous embodiment, the gap distance 7 is further reduced so that the vertical enclosure wall 3 is arranged close to the surface of the electrolytic cell 5 to maintain a small non-contact gap 11. Narrowing the gap distance 7 can reduce the probability of dust and sand entering the inside of the dust-proof cover structure 1 through this channel, and thus improve the protection effect on the support unit 2.

[0034] Furthermore, an airtight seal is provided at the non-contact gap 11. Specifically, such as Figure 5As shown, the dust-proof cover structure 1 can enclose the full-load mobile bracket inside, and the outside is the outdoor environment. In this embodiment, the inside enclosed by the dust-proof cover structure 1 is set as the replacement chamber 12. The bottom of the replacement chamber 12 is the installation base 4 of the electrolytic cell 5, and the bottom of its vertical enclosure wall 3 can form a sealed connection with the base 4. The top of the replacement chamber 12 is the bottom side of the electrolytic cell 5, and a non-contact gap 11 is formed between the upper side of the vertical enclosure wall 3 and the electrolytic cell 5 all around. The aforementioned airtight seal can be formed at least at the non-contact gap 11. Specifically, in the setting scenario of the electrolytic cell 5, a compressed air supply pipe 13 or a nitrogen gas pipeline can be provided, and a compressed gas pipeline with a certain pressure is connected into the replacement chamber 12. By continuously filling the replacement chamber 12 with compressed gas, continuous replacement is formed in the replacement chamber 12, and the replacement gas is blown out from the non-contact gap 11. It is also possible to establish a slightly positive pressure state in the replacement chamber 12 relative to the outside. Since the relatively narrow non-contact gap 11 is provided, on the one hand, it can improve the flow rate of the ejected gas and enhance the effect of preventing dust from entering, and on the other hand, it can reduce the gas usage flow rate. It can be understood that establishing continuous replacement can also bring out the heat carried in the replacement chamber 12, thus avoiding the problem of relatively high temperature inside the dust-proof cover structure 1. It is also possible to use a blower to fill the replacement chamber 12 with gas, and a filtering or washing device for the incoming gas can be provided on the intake side of the blower, so as to ensure the cleanliness of the gas entering the replacement chamber 12 and prevent dust from entering the rollers of the support unit 2 and avoid jamming. Embodiment 4:

[0035] As another embodiment of forming an airtight seal, in this embodiment, gas flow is formed inside the dust-proof cover structure 1 and a gas curtain 14 is ejected from a specific part to separate the external dust from the dust-proof cover structure 1. It can be understood that the gas curtain 14 is ejected and formed at the flexible connection 6 or the non-contact gap 11. On the basis of the base 4 in Embodiment 1, a brush structure 8 is provided, and a gas ejection port, that is, a specific part, can be further provided at the lower row of brushes 9, so that the brush structure 8 not only blocks dust through the bristles, but also ejects the gas curtain 14 at the same time, thereby enhancing the dust-blocking effect at the flexible connection 6. A continuously ejected gas curtain 14 can also be formed at the non-contact gap 11 to directly block the dust through the gas curtain 14.

[0036] As an implementation method, as Figure 6As shown, a ventilation opening 15 formed in the dust cover structure 1 is oriented in the preset gas outflow direction, and a gas jet outlet 16 is provided at least at the gas outflow end. Specifically, the inside of the vertical enclosure wall 3 is hollow, so its ventilation opening 15 is oriented towards the non-contact gap 11. Specifically, the ventilation opening 15 is set as the upper edge of the vertical enclosure wall 3, so that the cavity part 17 inside the vertical enclosure wall 3 communicates with the upper ventilation opening 15. It can be understood that a gas source such as that in Embodiment 3 can be used, and the gas source is connected to the cavity, so as to form an effect of blowing a continuous airflow from the inside of the vertical enclosure wall 3 to the non-contact gap 11 to form an air curtain 14. Embodiment 5:

[0037] As an improvement, based on the Coanda effect in this embodiment, the airflow is made to conform to the Coanda wall attachment to accelerate. Specifically, as Figure 7 shown, the gas laminar flow is guided to the continuously variable curvature Coanda surface 18, and the gradient surface of the Coanda surface 18 is used to make the gas produce the wall attachment effect, so that the gas flow rate is increased to form a jet air curtain 14.

[0038] This embodiment is different from Embodiment 4. In Embodiment 4, the vertical enclosure wall 3 can be understood as being hollow inside, and a ventilation opening 15 is provided at its top for air outlet, and its bottom and surroundings are of a closed structure; while in this embodiment, the inside of the vertical enclosure wall 3 is still hollow. The difference is that the dust cover structure 1 of this embodiment includes two parallel vertical enclosure walls 3, and the gap between the two vertical enclosure walls 3 is set as the ventilation opening 15; the side of the ventilation opening 15 close to the non-contact gap 11 is the gas jet outlet 16, and the ventilation opening 15 forms a gas suction inlet 19 at the end far from the gas jet outlet 16.

[0039] On the end faces of the mutually adjacent sides of the vertical enclosure wall 3, a Coanda surface 18 is formed. The Coanda surface 18 includes a curved convex portion 20 formed on the side away from the gas jet outlet 16. The curved convex portion 20 gradually transitions smoothly towards the gas jet outlet 16 to form an inclined surface 21. The opening directions formed by the two inclined surfaces 21 face the gas jet outlet 16. Further, similar to Embodiment 4, a cavity portion 17 is provided inside the vertical enclosure. The difference is that a slit-shaped air flow nozzle 22 for the gas to flow out in the tangential direction is provided at the starting section on the front side of the curved convex portion 20 of the cavity portion 17. In this embodiment, the air flow nozzle 22 is on the lower side, while in Embodiment 4, the gas ejection part is at the top. Compressed gas is introduced into the vertical enclosure wall 3, so that the gas is ejected through the slit-shaped air flow nozzle 22. The gas ejected from the slit-shaped air flow nozzle 22 can increase the flow velocity of the gas. The greater the flow velocity of the gas, the smaller the pressure. The gas flows along the Coanda surface 18, forming an effect of high flow velocity and low pressure. Furthermore, a region with low pressure is formed inside the through ventilation opening 15. The region with low pressure will drive and converge the air on the side of the gas suction port 19 towards the middle of the through ventilation opening 15. As a result, the flow rate of the air flow gushing out from the other gas jet outlet 16 is increased several times compared to the original flow rate from the slit-shaped air flow nozzle 22. Thus, a relatively small gas flow rate can leverage a larger amount of gas to pass through the through ventilation opening 15 and be ejected from the non-contact gap 11. During actual use, since the bottom of the vertical enclosure wall 3 is erected on the steel foundation 4, through holes 23 can be preset on the steel to communicate with the gas suction port 19, so that the through ventilation opening 15 is vertically through.

[0040] Specifically, the width of the through ventilation opening 15 is 10 - 25 mm; the protruding height H of the curved convex portion 20 is H = 8 mm (initial section) to H = 0 mm at the outlet section; the total length L of the Coanda surface 18 is 250 mm - 400 mm, meeting the acceleration length requirement: L ≥ 3D (D is the inlet equivalent diameter, D = 45 mm); Curvature parameter table

[0041] * The surface function is based on the differential geometric continuity condition (C² continuous) Performance test data: Inlet air velocity: 1.5 m / s (corresponding to the flow rate Q = 0.12 m³ / s) Dust characteristics: particle size 0.1 - 1.0 mm, concentration 1.2 g / m³ (simulating desert working conditions)

[0042] The Coanda surface adopts a continuously variable curvature design, the curvature radius R gradually changes from 50 mm to 200 mm, and the surface roughness Ra ≤ 0.8 μm (after polishing); and the surface is provided with a nano-aluminum oxide-polytetrafluoroethylene composite layer with a thickness of 30 ± 5 μm. Example Six:

[0043] Furthermore, the dust-proof cover structure 1 includes an ion wind generation module 24. As Figure 8 shown, the ion wind generation module 24 includes an electrode array 25. The electrode array 25 is provided with an emitter 26 and a collector 27. An ionization region 28 is arranged between the emitter 26 and the collector 27. The emitter 26 includes tungsten needle electrodes 29 arranged in front of the curved surface convex part 20. The collection region is a conductive silicon carbide layer 34 plated on the convex surface of the Coanda surface 18, and an electric field gradient is formed by grounding it. The electrode spacing in the ionization region 28 is 20 - 30 mm, the electric field strength E = 7.5 kV / cm, and corona discharge induces the formation of ion wind. The ion wind airflow passes through the Coanda surface 18 and is further accelerated by the pressure gradient generated by its curvature.

[0044] Taking the total length L = 300 mm of the Coanda surface 18 as an example, the specific parameters of this composite dust-proof cover structure 1 are as follows: the setting spacing of the tungsten needle electrodes 29 is 5 - 25 mm, the thickness of the silicon carbide conductive layer is about 80 μm, and the resistivity is 10² Ω·cm; the surface potential gradient ≤ 500 V / mm is satisfied (to prevent arc discharge); the geometric structure taper flow channel expansion angle θ of the ionization region 28 is 8°, so that the ion wind and the Coanda surface 18 are accelerated in coordination.

[0045] Coanda surface collaborative design: Curvature - electric field coupling parameter

[0046] The corona current generated by the ion wind is about 2.1 - 2.4 mA; the ion wind speed is not less than 4 m / s. The Coanda effect is triggered by the initial momentum of the ion wind (4.5 m / s), and the following are achieved by means of the wall attachment effect: the air flow speed is multiplied by 4.1 times (the theoretical limit is 4.8 times), and the protection area is expanded by 3.2 times.

[0047] The specific structural layout of this embodiment is as follows: The emitter 26 is at the front edge of the curved protrusion, and a row of tungsten needles (with a diameter of about 0.2 mm) is installed, and each tungsten needle is arranged at intervals. These tungsten needle electrodes 29 are connected to a high-voltage power supply, and tip discharge occurs during operation. The collector 27 uses conductive silicon carbide, which is used to receive the discharge of the tungsten needle electrode 29. A conductive silicon carbide layer 34 is plated on the entire surface of the curved protrusion to ground it; there is a 20-30 mm gap between the tungsten needle and the silicon carbide layer, and air is electroshocked and deformed into an ionic wind in this ionization region 28. The tungsten needle electrode 29 points to the curved protrusion, and ionization forms charged particles that attach to the wall and flow down along the Coanda surface 18, accelerating faster and faster as they flow, driving the surrounding air to flow together to form an ionic wind. When the ionic wind hits the surface, using the arc effect of the surface like a racing car bend (Coanda effect), the air flow will accelerate closely along the surface, just like water flowing down a slide faster and faster. The original wind speed of 4 m / s can be increased to nearly 15-20 m / s after passing through a 300-mm-long surface. Embodiment Seven:

[0048] Based on Embodiment Five and Embodiment Six, a negative pressure pipe 30 is provided on the vertical enclosure wall 3 near the full-load mobile bracket side, as Figure 9 shown. The vertically arranged enclosure walls 3 symmetrically arranged on both sides form a throat section 31 at the curved convex part 20. A reducing pipe 32 is formed at the front side of the throat section 31, and an expanding pipe 33 is formed at the rear side. One end of the negative pressure pipe 30 communicates with the throat section 31, and the other end communicates with the inner side of the semi-closed protection structure, that is, the inner side of the dust-proof cover structure 1.

[0049] This embodiment divides the vertical enclosure wall 3 into a throat section 31, a reducing pipe 32, and an expanding pipe 33 based on the principle of fluid dynamics; the throat section 31 uses the opposed arrangement of the curved convex part 20 to reduce the cross-section, the reducing pipe 32 at its front side has a gradually decreasing cross-section, and the expanding pipe 33 has a gradually increasing cross-section; when gas flows in a pipeline, the mass flow rate is constant; when the cross-sectional area decreases (throat section 31), the flow velocity increases. The increase in flow velocity (at the throat) causes the static pressure to decrease, forming a low-pressure area. Therefore, by connecting the negative pressure pipe 30 provided to the inner side of the dust-proof cover structure 1, the gas inside the dust-proof cover structure 1 can be extracted, thereby achieving the effects described in Embodiment Three, such as replacing the inside of the dust-proof cover structure 1 and preventing the internal heat from accumulating and rising, and no additional replacement gas source needs to be set.

[0050] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect, characterized in that: The following steps are involved: S1: A dust cover structure (1) is formed around the periphery of the full-load-bearing mobile bracket, which is in flexible contact with the electrolytic cell (5) or maintains a non-contact gap (11), and the dust cover structure (1) forms a semi-enclosed protective structure between the foundation (4) and the electrolytic cell (5); S2: airflow sealing, in which the inner chamber surrounded by the dust cover structure (1) is continuously filled with gas, or a gas flow is formed in the dust cover structure (1) and ejected from a specific position to form an air curtain (14), so that the dust cover structure (1) is separated from external dust; S3: Coanda wall acceleration, guiding the gas laminar flow to the Coanda surface (18) with continuous variable curvature, using the gradual curve of the Coanda surface (18) to make the gas produce a wall effect, so that the gas flow rate is increased, and a jet air curtain (14) is formed.

2. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that: The dust cover structure (1) comprises at least a vertical enclosure wall (3) arranged on the side of the full-load-bearing mobile bracket, the bottom of the vertical enclosure wall (3) is connected to the foundation (4), and the top is in flexible contact with the electrolytic cell (5) or forms a non-contact gap (11).

3. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that: The dust cover structure (1) is provided with a through vent (15) formed in a preset gas outflow direction, and the through vent (15) is provided with a gas jet outlet (16) at least at an end facing the gas outflow.

4. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 3, characterized in that: The through vent (15) forms a gas suction port (19) at one end away from the gas jet outlet (16), and the dust cover structure (1) includes vertical enclosure walls (3) arranged on both sides of the through vent (15), and the vertical enclosure walls (3) are close to each other on one side to form a Coanda surface (18), and the Coanda surface (18) includes a curved convex portion (20) formed on the side away from the gas jet outlet (16), and the curved convex portion (20) smoothly transitions to the gas jet outlet (16) side to form an inclined surface (21), and the opening direction formed by the inclined surfaces (21) on both sides faces toward the gas jet outlet (16).

5. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 4, characterized in that: The Coanda curved surface (18) adopts a continuously variable curvature design, and the curvature radius R gradually changes from 50 mm to 200 mm.

6. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 4 or 5, characterized in that: A cavity portion (17) is provided inside the vertical enclosure, and the cavity portion (17) is provided with a slit-shaped airflow nozzle (22) along a tangential direction for gas to flow out on the front side of the curved convex portion (20).

7. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 4 or 5, characterized in that: The dust cover structure (1) comprises an ion wind generating module (24), the ion wind generating module (24) comprises an electrode array (25), the electrode array (25) is provided with an emitter (26) and a collector (27), an ionization zone (28) is set between the emitter (26) and the collector (27), the emitter (26) comprises a tungsten needle electrode (29) arranged in front of the curved surface convex portion (20); the collector is a conductive silicon carbide layer (34) plated on the surface of the convex portion of the Coanda curved surface (18), and the electric field gradient is formed by grounding the conductive silicon carbide layer; the ionization zone (28) is set with an electrode spacing of 20-30 mm, and corona discharge induces ion wind, and the ion wind flows through the Coanda curved surface (18) and is further accelerated by the pressure gradient generated by its curvature.

8. A method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 4 or 5, characterized in that: A negative pressure pipe (30) is provided on the vertical enclosure wall (3) close to the full-load-bearing mobile bracket side. The vertical enclosure walls (3) symmetrically arranged on both sides form a throat section (31) at the curved convex portion (20). The throat section (31) forms a gradually converging pipe (32) at the front side and a gradually expanding pipe (33) at the rear side. One end of the negative pressure pipe (30) is connected to the throat section (31), and the other end is connected to the inside of the semi-enclosed protective structure.

9. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that: The dust cover structure (1) is made of transparent visible material.

10. The method for preventing sand and dust in an electrolytic cell based on the Coanda effect according to claim 1, characterized in that: The dust cover structure (1) is made of a material resistant to alkali corrosion.

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