Planar electrode, powder coating apparatus

Abstract

This invention relates to a planar electrode and a powder coating equipment. The planar electrode includes a panel and multiple electrode needle assemblies distributed on the panel. The electrode needle assemblies are connected to a high-voltage electrostatic discharge to generate corona discharge, thereby charging the powder. The powder coating equipment includes a pair of planar electrodes, forming a powder spraying channel between the two electrodes. Powder spraying pipes are symmetrically arranged on both sides of the front end of the channel, and exhaust pipes are arranged on both sides of the rear end to maintain a negative pressure in the channel. By setting grounding needle assemblies on both sides of the workpiece inlet, free electrons in the electric field that are not attached to the powder are absorbed, effectively preventing reverse ionization. This invention replaces the traditional single-point electrode needles with a planar distribution, forming a uniform planar electric field, which allows the powder to be fully and uniformly charged, significantly improving the powder application rate to nearly 100%. It can achieve a uniform thin coating of 20-40μm, eliminate defects such as orange peel and pinholes, and improve the powder application effect in complex structures such as grooves, greatly saving powder material and improving coating quality.

Description

Technical Field

[0001] This invention relates to the field of powder coating, specifically to a planar electrode and powder coating equipment. Background Technology

[0002] Most existing electrostatic powder coating equipment uses a structure where the spray gun has a built-in single-point electrostatic needle. A strong electric field is created between the spray gun and the grounded workpiece, ionizing the air in between—a phenomenon known as corona discharge. When corona discharge occurs, air molecules (such as oxygen and nitrogen) are bombarded by electrons, generating a large number of charged ions and free electrons. The powder coating sprayed into the workpiece becomes charged with these ions and, driven by the electric field, drifts and is adsorbed onto the surface of the grounded workpiece. Once the desired thickness is achieved, the workpiece enters an oven where it is cured at high temperature to form a powder coating. This is the principle of high-voltage electrostatic powder coating. Currently, the global powder coating industry uses electrostatic powder coating guns with high-voltage electrostatic needles installed on the spray gun head. However, the commonly used corona electrostatic powder coating equipment has some insurmountable drawbacks that limit the better application of powder coating. Firstly, as charged powder is adsorbed and accumulates layer by layer onto the workpiece, a considerable number of free electrons also follow. When the accumulated negative charge exceeds a certain limit, reverse ionization occurs. This means that due to the mutual repulsion of negative charges, the adsorbed powder is bounced off the workpiece surface, resulting in pinholes or pits after the coating cures, severely affecting the surface quality. Another drawback of traditional electrostatic powder coating equipment is that, due to the Faraday cage effect, it is difficult to apply powder to grooves and other areas on the workpiece. Solving these problems that plague the entire industry has always been a major technical challenge, and resolving these issues has the value of benefiting the entire industry. We have found that the reverse ionization phenomenon in powder coatings is related to many factors, including electric field strength, coating thickness, coating performance, and powder application rate. Higher voltage results in a stronger electrostatic field at the same distance. While charged powder is adsorbed, a large number of free electrons are also adsorbed, and the combined effect of both leads to reverse ionization. Reverse ionization is more likely to occur when the powder particle size is finer because as the particle size decreases, the specific surface area of ​​the powder increases exponentially, making it easier for the powder to carry more charge. We also found that free electrons do not have a positive effect on our powder coating. If we can find a way to reduce the number of free electrons attached to the workpiece while maintaining the number of charged powder particles, we can greatly slow down or avoid reverse ionization, thereby greatly improving the coating quality.

[0003] Powder is charged by corona discharge and then adsorbed onto the workpiece surface. However, this technology has the following drawbacks: First, the electric field generated by a single-point electrocautery needle is highly concentrated, resulting in large differences in powder application rate and uneven coating thickness in different parts of the workpiece (such as edges, surfaces, and grooves). In actual production, the film thickness has to be controlled at 60-100μm, which is much higher than the 20-40μm of liquid coating, resulting in material waste.

[0004] Second: The electric field shielding is severe in complex structures such as grooves and inner corners, making it difficult for powder to enter and apply powder.

[0005] Third: Free electrons that are not attached to the powder accumulate on the surface of the workpiece, and as the coating thickens, they cause reverse ionization, resulting in coating defects such as pits and pinholes.

[0006] Fourth: The electric field coverage is limited, and some powder is dispersed before it is fully charged, resulting in an initial powder application rate of only about 60%-70%.

[0007] Therefore, there is an urgent need for a powder coating equipment with a uniform electric field and a large area, which can effectively control free ions, reduce powder accumulation, and improve powder application efficiency and coating smoothness. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a planar electrode and powder coating equipment to solve the technical problems of uneven electric field distribution and uneven coating thickness caused by the existing single-point electric needle structure of powder coating equipment.

[0009] The technical solution adopted by this invention to solve its technical problem is: First aspect: A planar electrode is provided, comprising: The panel and multiple electrostatic needle assemblies distributed on the panel, wherein the electrostatic needle assemblies are connected to a high voltage electrostatic generator to generate corona discharge to charge the powder.

[0010] Furthermore, the electroacupuncture assembly includes an electroacupuncture base and a metal electroacupuncture needle; the electroacupuncture base has an insulating fixing hole and a needle body channel coaxially formed, and an air blowing hole communicating with the needle body channel; the insulating layer of the metal electroacupuncture needle is fixed in the insulating fixing hole, and the needle body of the metal electroacupuncture needle extends into the needle body channel; pressurized gas enters the needle body channel through the air blowing hole and is then ejected outward to prevent dust from adsorbing onto the surface of the metal electroacupuncture needle.

[0011] Furthermore, the panel is a flat panel.

[0012] Furthermore, the panel is a curved panel or a panel with bends.

[0013] The second aspect: providing a powder coating device, including: One side of the surface electrode uses the aforementioned surface electrode; a powder spraying channel is formed between the two surface electrodes, and the entire powder spraying channel is within the electric field generated by the two surface electrodes; The front end of the powder spraying channel is the workpiece inlet, and the rear end is the workpiece outlet. The flat plate to be sprayed with powder enters the powder spraying channel from the workpiece inlet and then moves out from the workpiece outlet. Two rows of powder spraying pipes are symmetrically arranged on both sides of the workpiece inlet for spraying powder into the powder spraying channel; A pair of exhaust ducts are respectively installed on both sides of the workpiece outlet. When the exhaust ducts are in operation, they are suitable for extracting the air from the powder spraying channel to ensure that the powder spraying channel is under negative pressure and to prevent dust from overflowing.

[0014] Furthermore, at least one grounding pin assembly for receiving free electrons in the electric field is provided, the grounding pin assembly being installed on both sides of the workpiece inlet; The grounding pin assembly is located between the planar electrode and the flat plate. The distance between the grounding pin assembly and the planar electrode is less than the distance between the planar electrode and the flat plate. The grounding pin assembly avoids the direction of dust ejected from the powder spraying pipe.

[0015] Furthermore, the grounding needle assembly includes a needle base and a grounding needle; the needle base is coaxially provided with an insulation fixing hole and a needle body channel, and is provided with an air blowing hole communicating with the needle body channel; The grounding pin is insulated and fixed in the insulating fixing hole, and the front end of the grounding pin extends into the pin body channel; high-pressure gas enters the pin body channel through the air blowing hole and is sprayed outward to remove the powder accumulated on the surface of the grounding pin.

[0016] Furthermore, the exhaust pipe is vertically oriented and connected to the panel, with an air inlet on the exhaust pipe that is flush with the panel.

[0017] Furthermore, an exhaust pipe is installed at the bottom of the powder spraying channel. The exhaust pipe, together with the exhaust pipes on both sides, draws out the air in the channel, creating a relative negative pressure in the channel.

[0018] The beneficial effects of this invention are: The planar electrode of this invention uses multiple electrode needle components distributed across a planar surface to form a planar electric field, replacing the traditional single-point electrode needle structure. This results in a more uniform powder distribution within the electric field, with a sufficiently large area. Consequently, the high voltage required to achieve the same charging effect can be significantly lower. The powder not only charges fully and uniformly as it passes through, but also significantly reduces the difference in powder application rate between different parts of the workpiece (edges, surfaces, grooves). The result of uniform coating is the ability to achieve thin (as low as 20-40 μm) and uniform coatings, greatly saving powder material. This is something that traditional powder coating equipment struggles to achieve.

[0019] The powder coating equipment of this invention employs one or two planar electrodes. The planar electrodes allow the powder to be uniformly charged over a large area, increasing the probability of powder charging. After the free ion collector absorbs excess free ions, the electric field strength is appropriately reduced, and the powder itself is fully charged. This results in a smaller Faraday cage effect under a smaller electric field. Furthermore, the powder, being self-charged, can still be adsorbed by the workpiece at grooves with the assistance of airflow. This mechanism effectively alleviates the Faraday cage effect at complex structures such as grooves and inner corners, allowing powder to penetrate areas that are difficult to cover with traditional equipment, achieving uniform powder coating across the entire surface.

[0020] The planar electric field covers the entire powder spraying channel, extending the residence time of the powder within the channel and allowing for more complete charging. Simultaneously, because the electric field is uniform and controllable, the powder does not need to be propelled by a strong electric field, significantly reducing the amount of uncharged or insufficiently charged powder drifting into the environment. The initial powder application rate can be increased to nearly 100%, reducing powder waste and recycling costs.

[0021] Both the electrode assembly and the grounding electrode assembly have internal insulation fixing holes, electrode channels, and air blowing holes. High-pressure gas continuously blows through them, effectively removing dust accumulated on the surfaces of the electrode and grounding electrode in real time. This avoids problems such as unstable discharge and reduced ion collection efficiency caused by dust accumulation, reduces the frequency of equipment downtime for cleaning, and improves production continuity and equipment stability.

[0022] By installing grounding pin assemblies (free ion collectors) on both sides of the workpiece inlet, free ions that are not attached to the powder in the electric field are effectively absorbed, reducing the number of ions reaching the workpiece surface. This avoids reverse ionization caused by the accumulation of free ions during coating thickening, eliminates defects such as orange peel and pinholes on uneven surfaces, and significantly improves the surface quality and smoothness of the coating.

[0023] The placement of the grounding pin assembly, acting as a free electron absorber, is crucial. It must be positioned between the workpiece and the planar electrode, at a distance smaller than the distance between the electrode and the workpiece, but away from the direction of the dust ejected from the spray gun. The powder ejected from the spray gun, due to its forward momentum, will not be collected by the free electron collector, while free electrons are easily absorbed. Because the distance between the absorber's electric pin and the electrode is short, the electric field strength is very high, resulting in a strong corona discharge, making it easy for the powder injected into it to become charged.

[0024] The powder coating rate is closely related to the amount of powder charge. A stronger electric field results in a stronger corona discharge, making it easier for the powder to become charged. However, moving spray guns and irregular workpieces always create a very uneven high-voltage electric field, leading to uneven charging and increasing the probability of extreme situations, which in turn increases the probability of reverse ionization. This invention first separates the electrostatic needles on the spray gun and arranges them evenly on a panel. Separating the needles from the powder coating has many advantages: firstly, it creates a large-area, uniform electric field, greatly increasing the probability of powder becoming charged and the probability of charged powder being driven by a multiplied electric field; secondly, it achieves the same charging and powder coating effect with a significantly reduced voltage. Lowering the voltage reduces the number of free electrons generated and the amount of charged powder, greatly mitigating the probability of reverse ionization; thirdly, the panel also acts as a seal, isolating the powder coating space, preventing powder drift, and greatly improving the powder coating rate. In summary, the planar electrode increases the charging space, reduces the charging intensity, and achieves a higher powder coating rate while avoiding a series of side effects caused by excessively high electrostatic fields. Attached Figure Description

[0025] The invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram (top view) of a planar electrode coating equipment; Figure 2 This is a schematic diagram of the electrocautery assembly; Figure 3 This is a schematic diagram of a right-angled panel; Figure 4 This is a schematic diagram of a curved panel; Among them, 1. Panel; Electroacupuncture assembly, 21. Electroacupuncture base, 211. Air inlet; 22. Metal electroacupuncture needle; 3. Powder spraying pipe; 4. Exhaust pipe; 5. Grounding pin assembly; 6. Flat panel materials. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0028] like Figure 1 and Figure 2 As shown, this embodiment provides a planar electrode, including a panel 1 and a plurality of electrocautery needle assemblies 2 distributed on the panel 1. The electrocautery needle assemblies 2 are connected to a high-voltage electrostatic discharge to generate corona discharge to charge the powder.

[0029] Compared to traditional single-point electrocautery structures, the planar electrode of this invention uses multiple electrocautery components arrayed on the panel to form a uniform planar electric field. This allows the powder passing through this electric field to be fully and uniformly charged, significantly reducing the difference in powder application rate between different parts of the workpiece (such as edges, planes, and grooves) during subsequent coating. This provides a key foundation for achieving thin (as low as 20-40 μm) and uniform coatings, and helps to significantly save powder materials.

[0030] like Figure 2 As shown, this embodiment further defines the specific structure of the electrocautery assembly 2 based on embodiment 1. The electrocautery assembly 2 includes an electrocautery base 21 and a metal electrocautery needle 22. The electrocautery base 21 has an insulating fixing hole and a needle body channel coaxially formed, and an air blowing hole 211 communicating with the needle body channel. The insulating layer of the metal electrocautery needle 22 is fixed within the insulating fixing hole, and the needle body of the metal electrocautery needle 22 extends into the needle body channel. Pressurized gas enters the needle body channel through the air blowing hole 211 and is then ejected outwards to prevent dust from adsorbing onto the surface of the metal electrocautery needle 22.

[0031] This structure effectively avoids discharge instability caused by powder accumulation through continuous airflow purging, reduces the frequency of equipment downtime for cleaning, and improves production continuity.

[0032] This embodiment describes the shape of panel 1 based on embodiment 1. Panel 1 can be a flat plate to accommodate the coating of flat materials. Alternatively, panel 1 can also be a curved panel or a panel with bends (such as...). Figure 3 and Figure 4 As shown), a panel with bends refers to a panel such as... Figure 3 The panel shown has a right-angle structure formed by a bend. The bending angle and number of bends are determined according to actual needs to adapt to the coating requirements of workpieces with different shapes and enhance the applicability of the equipment. When only one side of the workpiece needs to be coated, a surface electrode can be set on the side opposite to the surface to be coated and high-voltage electrostatic discharge can be turned on.

[0033] like Figure 1 As shown, this embodiment provides a powder coating device, including a pair of face electrodes, two rows of powder spraying pipes 3 and a pair of exhaust pipes 4.

[0034] The two planar electrodes are as described in the previous planar electrode embodiment, and the panel of the planar electrode is a flat plate. A powder spraying channel is formed between the two planar electrodes, and the entire powder spraying channel is within the uniform electric field generated by the two planar electrodes. The front end of the powder spraying channel is the workpiece inlet, and the rear end is the workpiece outlet. The flat plate 6 to be powdered enters the powder spraying channel from the workpiece inlet and then exits from the workpiece outlet. Two rows of powder spraying pipes 3 are symmetrically arranged on both sides of the workpiece inlet for spraying powder into the powder spraying channel. A pair of exhaust pipes 4 are respectively arranged on both sides of the workpiece outlet. When the exhaust pipes 4 are in operation, they are suitable for extracting air from the powder spraying channel to ensure a relative negative pressure inside the powder spraying channel and prevent dust from overflowing. The air drawn into the exhaust pipes moves in a spiral motion in the pipes to prevent powder from adhering to the inner wall.

[0035] For details on the exhaust duct, please refer to the prior patent (CN115739473A-Exhaust mechanism to prevent powder accumulation, painting spray booth).

[0036] This equipment uses planar electrodes to uniformly charge the powder over a large area, increasing the probability of powder charging. The planar electric field covers the entire powder spraying channel, extending the powder's residence time within the channel and resulting in more complete charging. Simultaneously, because the electric field is uniform and controllable, the powder does not need to be driven by a strong electric field force to fly, significantly reducing the dispersion of uncharged or insufficiently charged powder. The initial powder application rate can be increased to nearly 100%, reducing powder waste and recycling costs.

[0037] like Figure 1 As shown, this embodiment, based on embodiment 4, further includes at least one grounding pin assembly 5. The grounding pin assembly 5 is located between the planar electrode and the flat plate 6, the distance between the grounding pin assembly 5 and the planar electrode is less than the distance between the planar electrode and the flat plate 6, and the grounding pin assembly 5 avoids the direction of dust ejected from the powder spraying pipe 3.

[0038] The structure of the grounding needle assembly 5 is similar to that of the electric needle assembly 2, including a needle base and a grounding needle. An insulating fixing hole and a needle body channel are coaxially formed within the needle base, and an air blowing hole communicating with the needle body channel is also provided. The grounding needle is insulated and fixed within the insulating fixing hole, and the front end of the grounding needle extends into the needle body channel. High-pressure gas enters the needle body channel through the air blowing hole and is then ejected outwards to prevent powder accumulation on the surface of the grounding needle.

[0039] The grounding pin assembly 5 acts as a free electron absorber, absorbing free electrons that are not attached to the powder within the electric field, thereby reducing the total charge of the powder adsorbed on the workpiece. By absorbing excess free electrons, it can effectively avoid reverse ionization caused by excessive charge during coating thickening, eliminate defects such as orange peel, pinholes, and unevenness, and significantly improve the surface quality of the coating.

[0040] This embodiment further optimizes the arrangement of the exhaust pipe 4 based on embodiment 4. The exhaust pipe 4 is arranged vertically and connected to the panel 1. An air inlet is opened on the exhaust pipe 4 and is attached to the panel 1. The gas entering the pipe rotates downward, which can reduce dust accumulation on the wall.

[0041] In addition, a bottom exhaust pipe can be installed at the bottom of the powder spraying channel. This bottom exhaust pipe, together with the exhaust pipes 4 on both sides, draws air out of the channel, creating a relative negative pressure within the channel. This structure helps to form a stable airflow path, ensuring that the powder moves uniformly in the electric field and further improving the powder coating efficiency.

[0042] Combination Figure 1 and Figure 2 The working process of the powder coating equipment of the present invention is as follows: The flat plate 6 to be powdered enters the powder spraying channel from the workpiece inlet, and the powder spraying pipe 3 sprays powder into the channel. The powder is fully charged in the uniform planar electric field generated by the planar electrode and moves along the channel under the action of the negative pressure airflow guided by the exhaust pipe 4. During this process, the grounding pin assembly 5 installed on both sides of the workpiece inlet preferentially absorbs free electrons, reducing the total amount of charge adsorbed on the workpiece surface. Finally, the fully charged powder is uniformly adsorbed on the workpiece surface under the action of the electric field force. Because the accumulation of free electrons is effectively controlled, reverse ionization is avoided, thereby completing high-quality coating.

[0043] The equipment of the present invention is conducive to the precise adjustment and control of the spraying process. It can adjust the distance between the panel 1 and the workpiece, the electric field strength, the number, arrangement position and spraying angle of the powder spraying tubes 3, and even install more spray guns in difficult powdering positions, laying the equipment foundation for digital and intelligent powder spraying.

[0044] This embodiment further clarifies the core innovative mechanism of the present invention, namely, separating the high-voltage electrode from the powder spraying gun and combining it with a free electron collector (grounding pin assembly 5), thereby obtaining a technical effect completely different from that of the traditional electrostatic powder spraying gun.

[0045] In traditional electrostatic powder coating equipment, the high-voltage electric needle is integrated inside the powder coating gun head, so the powder is simultaneously charged and accelerated at the moment of spraying. This integrated structure has the following inherent defects: the electric field is highly concentrated near the spray gun exit and the distribution is extremely uneven; the powder charging time is short and insufficient; and a high voltage must be applied to achieve a sufficient powder coating rate, which exacerbates reverse ionization and the Faraday cage effect.

[0046] This invention employs a structural design that separates the electrodes from the powder spraying gun: planar electrodes are independently positioned on both sides of the powder spraying channel, forming a large-scale planar electric field; the powder spraying pipes 3 are symmetrically positioned on both sides of the workpiece inlet, independent of the electrodes; after the powder is sprayed from the powder spraying pipes 3, it first enters the planar electric field region and then becomes charged, rather than being charged simultaneously at the moment of spraying. The resulting technical effects are: The charging time is significantly extended: the powder remains in the electric field as it passes through the entire powder spraying channel, resulting in more complete and uniform charging. Electric field strength can be reduced: Due to improved charging efficiency, sufficient charge can be obtained for the powder without high voltage, and the working voltage can be reduced by 30%-50% compared to traditional equipment; Uniform electric field distribution: The planar electrode makes the electric field cover the entire channel cross section, eliminating the electric field "peak" area of ​​traditional spray guns, and the electric field effect on all parts of the workpiece is consistent.

[0047] Based on the separation of the electrode from the powder spraying gun, this invention further incorporates a grounded free electron collector. Free electrons are extremely light, have low inertia, and are easily driven by an electric field; a local strong electric field region is formed between the free electron collector and the electrode needle, preferentially capturing free electrons in the electric field that are not attached to the powder; due to its relatively large mass, the powder can pass through this region without being absorbed by inertia, and at the same time, it becomes further charged in this region.

[0048] This invention achieves an electrostatic spraying principle completely different from traditional spray guns through two collaborative innovations: separation of the electrode from the powder spraying gun and a free electron collector. First: From "point electric field" to "surface electric field": This completely changes the electric field distribution pattern and eliminates excessively strong local electric fields; Second: From "instantaneous charging" to "continuous charging": The powder is fully charged in the channel, reducing its dependence on high voltage; Third: From "free electron interference" to "controllable absorption of free electrons": actively capturing free electrons and eliminating their negative impact on the coating; Fourth: From "forced adsorption at excessively high voltage" to "fully charged adsorption at low voltage": achieving higher powder application rate and better coating quality under normal voltage.

[0049] These differences enable the present invention to achieve a thin coating (20-40μm), uniform coating, no orange peel, no pinholes, and full powder coating of grooves that traditional spray guns cannot achieve. At the same time, the initial powder coating rate is close to 100%, which greatly saves powder materials, reduces the recycling burden, and provides a feasible equipment foundation for intelligent, digital, and precise spraying control.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A planar electrode, characterized in that, include: The panel and multiple electrostatic needle assemblies distributed on the panel, wherein the electrostatic needle assemblies are connected to a high voltage electrostatic generator to generate corona discharge to charge the powder.

2. The planar electrode according to claim 1, characterized in that, The electrocautery assembly includes an electrocautery base and a metal electrocautery needle; the electrocautery base has an insulating fixing hole and a needle body channel coaxially formed, and an air blowing hole communicating with the needle body channel; the insulating layer of the metal electrocautery needle is fixed in the insulating fixing hole, and the needle body of the metal electrocautery needle extends into the needle body channel; pressurized gas enters the needle body channel through the air blowing hole and is then ejected outward to prevent dust from adsorbing onto the surface of the metal electrocautery needle.

3. The planar electrode according to claim 1, characterized in that, The panel is a flat panel.

4. The planar electrode according to claim 1, characterized in that, The panel is a curved panel or a panel with bends.

5. A powder coating equipment, characterized in that, include: One of the planar electrodes uses the planar electrode described in any one of claims 1-3; A powder spraying channel is formed between the two planar electrodes, and the entire powder spraying channel is within the electric field generated by the two planar electrodes; The front end of the powder spraying channel is the workpiece inlet, and the rear end is the workpiece outlet. The flat plate to be sprayed with powder enters the powder spraying channel from the workpiece inlet and then moves out from the workpiece outlet. Two rows of powder spraying pipes are symmetrically arranged on both sides of the workpiece inlet for spraying powder into the powder spraying channel; A pair of exhaust ducts are respectively installed on both sides of the workpiece outlet. When the exhaust ducts are in operation, they are suitable for extracting the air from the powder spraying channel to ensure that the powder spraying channel is under negative pressure and to prevent dust from overflowing.

6. The powder coating equipment according to claim 5, characterized in that, Also includes At least one grounding pin assembly for receiving free electrons in an electric field, the grounding pin assembly being installed on both sides of the workpiece inlet; The grounding pin assembly is located between the planar electrode and the flat plate. The distance between the grounding pin assembly and the planar electrode is less than the distance between the planar electrode and the flat plate. The grounding pin assembly avoids the direction of dust ejected from the powder spraying pipe.

7. The powder coating equipment according to claim 6, characterized in that, The grounding needle assembly includes a needle base and a grounding needle; the needle base has an insulating fixing hole and a needle body channel coaxially formed inside, and an air blowing hole communicating with the needle body channel; The grounding pin is insulated and fixed in the insulating fixing hole, and the front end of the grounding pin extends into the pin body channel; high-pressure gas enters the pin body channel through the air blowing hole and is sprayed outward to remove the powder accumulated on the surface of the grounding pin.

8. The powder coating equipment according to claim 5, characterized in that, The exhaust pipe is vertically arranged and connected to the panel. An air inlet is provided on the exhaust pipe and is attached to the panel.

9. The powder coating equipment according to claim 5, characterized in that, A bottom exhaust pipe is installed at the bottom of the powder spraying channel. The bottom exhaust pipe, together with the exhaust pipes on both sides, draws out the air in the channel, creating a relative negative pressure in the channel.

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