A powder spray device

Abstract

This invention relates to the field of electrostatic powder coating technology and discloses a powder coating device, including a spray gun nozzle, a plurality of spray gun nozzles arranged at intervals, and a baffle plate disposed between two adjacent spray gun nozzles. The baffle plates on both sides of the spray gun nozzles are symmetrically arranged, and each spray gun nozzle is installed on the same horizontal plane. The ends of two adjacent baffle plates are connected, and the ends of each baffle plate are located on the same horizontal plane, which is parallel to the horizontal plane where the spray gun nozzles are located. The powder sprayed from the spray gun nozzles passes through the ends of the baffle plates on both sides and can perform spraying on the material to be coated in a manner that meets the spraying requirements. Its advantage is that it can intercept uneven powder spray and improve the uniformity of powder coating.

Description

Technical Field

[0001] This invention relates to the field of electrostatic powder coating technology, and more particularly to a powder coating apparatus. Background Technology

[0002] Electrostatic powder coating is an advanced coating technology that uses a high-voltage electrostatic corona field to uniformly adsorb powder coating onto the surface of a workpiece, followed by heating and curing to form a robust coating. During electrostatic powder coating, the workpiece is transported to the spray gun position, ready for the coating operation. An electrostatic generator releases high-voltage static electricity (usually negative) towards the workpiece through the electrode needle at the spray gun nozzle. This high-voltage static electricity ionizes the mixture of powder and compressed air ejected from the spray gun nozzle, as well as the air around the electrode, giving it a negative charge. Simultaneously, the workpiece is connected to the ground via a hanger (i.e., connected to the grounding electrode), thus creating an electric field between the spray gun and the workpiece. Under the combined action of the electric field force and the compressed air pressure, the powder is pushed towards the workpiece surface and uniformly deposited on the workpiece by electrostatic attraction, forming a continuous and dense coating.

[0003] However, the powder sprayed from the spray gun is distributed in a cone shape, and the dust concentration at the edges is thin. This results in the powder thickness on both sides of the spray path being thinner than the powder thickness in the middle area, causing uneven powder coverage on the workpiece.

[0004] In summary, this powder coating device can intercept uneven powder spray and improve the uniformity of powder coating. Summary of the Invention

[0005] In view of the problem of uneven coverage thickness of powder sprayed from the spray gun on the two edge areas of the workpiece in the existing technology, a powder spraying device is proposed that can intercept the uneven powder spray and improve the uniformity of powder spraying.

[0006] To solve the above problems, the technical solution of the present invention is as follows: A powder coating apparatus includes a spray gun nozzle, a plurality of spray gun nozzles arranged at intervals, and a baffle plate disposed between two adjacent spray gun nozzles. The baffle plates on both sides of the spray gun nozzles are symmetrically arranged, and each spray gun nozzle is mounted on the same horizontal plane. The ends of two adjacent baffle plates are located on the same horizontal plane, and this horizontal plane is parallel to the horizontal plane where the spray gun nozzles are located. The powder sprayed from the spray gun nozzles passes through the ends of the baffle plates on both sides and can perform a coating on the material to be coated in accordance with the coating requirements.

[0007] As a preferred technical solution, the barrier plate is a conveyor belt structure, wherein the surface of the barrier plate in contact with the powder changes cyclically.

[0008] As a preferred technical solution, a powder scraper is provided in the area where the barrier plate does not contact the powder sprayed from the spray gun nozzle, and the powder scraper can scrape the powder on the barrier plate.

[0009] As a preferred technical solution, the powder scraper is a cavity structure with scraping grooves, the cavity structure is connected to a negative pressure mechanism, and the negative pressure mechanism is used to extract the powder in the cavity structure.

[0010] As a preferred technical solution, the end of the barrier plate is provided with a negative pressure powder suction port, which faces the plate to be sprayed with powder, and the negative pressure powder suction port can suck out the powder from the spraying area.

[0011] As a preferred technical solution, the barrier plate is provided with a movable adjustment end, which allows the distance between the ends of adjacent barrier plates to move closer or further apart.

[0012] As a preferred technical solution, the powder sprayed from two adjacent spray nozzles crosses outside the barrier plate.

[0013] As a preferred technical solution, the surface of the material to be coated does not exceed the intersection.

[0014] The beneficial effects of this invention are: 1. In the powder coating apparatus of the present invention, when the spray gun nozzle performs spraying, the sprayed powder is ejected in a cone shape. Because the present invention provides baffles on both sides of the spray gun nozzle, the powder in the unstable areas on both sides of the cone-shaped powder is blocked by the baffles before contacting the surface of the material to be coated, and is directly adsorbed onto the baffles. Meanwhile, the powder with a uniform center passes through the end of the baffles and coats the material, resulting in a uniform powder thickness covering the material. Furthermore, several spray gun nozzles and baffles are arranged in a straight line, and the ends of the baffles are interconnected, allowing the areas covered by each spray gun nozzle on the material to be interconnected, achieving automated and uniform coating of the entire material.

[0015] 2. The barrier plate of the powder coating device of the present invention is a conveyor belt structure driven by a rotating drum. The conveyor belt has two sets of alternating rotating contact surfaces. Compared with a fixed barrier plate, its effective contact area is at least twice that of a fixed barrier plate, thereby increasing the powder holding capacity. The conveyor belt barrier plate rotates only cyclically under the drive of the drive roller shaft, switching between the spraying area and the non-spraying area. In the non-spraying area, i.e., the area of ​​the conveyor belt that is not opposite to the spray gun nozzle, a powder scraper is provided. The powder scraper has a V-shaped scraping groove, and the edge of the powder scraper is flush with the back of the conveyor belt. The areas are closely spaced, and as the conveyor belt moves, the edge of the conveyor belt and the powder scraper move relative to each other. The powder on the conveyor belt is separated from the conveyor belt and collected by the powder scraper. The conveyor belt with the powder removed re-enters the powder spraying area from the end, and re-adsorbs the powder on the conical edge. This makes the powder spraying device of the present invention suitable for long-term and high-concentration powder spraying operations. The powder on the powder scraper can also be directly sucked and transferred by the negative pressure device, further improving the effective working time and saving the time of dealing with the powder on the barrier plate or powder scraper.

[0016] 3. In the powder coating device of the present invention, a negative pressure suction port connected to a negative pressure device is provided directly above the overlapping powder coating area created by adjacent spray nozzles on the board. During the powder coating operation, the negative pressure device provides a suction effect, and part of the powder on the overlapping powder coating area is sucked out through the negative pressure suction port, preventing it from settling on the board, thereby reducing the powder thickness of the overlapping coating area and improving the uniformity of the coating. Moreover, by adjusting the magnitude of the negative pressure suction, the powder thickness of the corresponding area can be controlled. At the same time, the generated negative pressure area provides orderly guidance for the airflow that originally sprayed from the spray nozzle and hit the baffle plate, so that this part of the airflow can move orderly along the baffle plate and be sucked out of the coating system, avoiding rebound impact on the powder in the central coating area, causing uneven powder coating, and ensuring the overall uniformity of the coating area.

[0017] 4. The powder coating device of the present invention has a rotatable adjustable end at one end of the baffle plate near the spray gun nozzle, which can move the ends of adjacent baffle plates away from each other or closer together, greatly increasing the flexibility of the powder coating device. When the ends of the baffle plates move away from each other, the effective spraying area of ​​the spray gun nozzle narrows, thereby reducing the overlapping spraying area of ​​two adjacent spray gun nozzles and improving the overall uniformity of powder coating. At the same time, in conjunction with the negative pressure powder suction port of the powder coating device, the adjustment of the powder coating accuracy of the overlapping spraying area is greatly improved. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of the powder coating device described in this invention; Figure 2This is a partially enlarged schematic diagram of the spraying operation area of ​​the powder spraying device described in this invention; Figure 3 This is a schematic diagram showing the positions of the barrier plate and the substrate to be coated in the powder coating device of the present invention. Figure 4 This is a schematic diagram showing the relationship between the powder sprayed from the nozzle of the powder spraying device described in this invention and the limiting effect of the barrier plate. Figure 5 This is a schematic diagram of the powder coating device of the present invention, which includes a barrier plate in the form of a conveyor belt. Figure 6 A partial schematic diagram of a powder coating device with a barrier plate in the form of a conveyor belt. Figure 7 A partial cross-sectional schematic diagram of a powder coating device with a barrier plate in the form of a conveyor belt. Figure 8 This is a schematic diagram of a partial spraying area of ​​the powder spraying device described in this invention; Figure 9 This is a schematic diagram of a powder suction port with negative pressure and a rotatable baffle plate.

[0019] The reference numerals and components involved in the accompanying drawings are shown below: 1. Spray gun nozzle; 2. Barrier plate; 3. Sheet material; 4. Powder scraper; 41. Scraper groove; 5. Negative pressure powder suction port; 6. Conveying mechanism. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1; please refer to the appendix. Figure 1 Appendix Figure 2 , Figure 1 This is a three-dimensional schematic diagram of the powder coating device described in this invention. Figure 2This is a partially enlarged schematic diagram of the spraying operation area of ​​the powder coating device of the present invention. A powder coating device includes a spray nozzle 1 and a baffle plate 2. The baffle plate 2 can be installed via a telescopic mounting bracket 7, allowing for flexible adjustment of the distance between the baffle plate 2, the spray nozzle 1, and the substrate 3 to be coated. Several spray nozzles 1 are arranged at equal intervals along a straight line, and each spray nozzle 1 is located on the same horizontal plane. Preferably, this straight line is perpendicular to the forward direction of the substrate 3 to be coated, and the horizontal plane is parallel to the surface of the substrate 3 and located above the substrate 3. Because the powder sprayed from the spray nozzle 1 diffuses in a cone shape, and the powder concentration at the edge of the cone is lower than that in the center, the powder velocity is also lower than that in the center. Therefore, it is easily affected by external factors, resulting in irregular diffusion. Thus, when using it for automated spraying of the substrate 3, the powder deposits on... The powder on the surface of the substrate 3 is thinner on the sides than in the center, and the powder coverage on the sides is not concentrated. This results in scattered powder coverage even at the far ends of the substrate 3, away from the spraying center. In existing technologies, when performing automated powder coating on substrate 3, the spray nozzles 1 are usually arranged equidistantly in a straight line, with a conveyor mechanism 6 below the spray nozzles 1 to transport the substrate 3. The substrate 3 is placed on the conveyor mechanism 6, and it passes uniformly under the spray nozzles 1 driven by the conveyor mechanism 6. Since the conical edges of adjacent spray nozzles 1 overlap, they overlap on the surface of the substrate 3, resulting in uneven powder thickness. To solve the above problem, in the powder coating device of the present invention, a baffle plate 2 is provided between two adjacent spray nozzles 1, and the baffle plates 2 on both sides of each spray nozzle 1 are symmetrically arranged. Preferably, please refer to the appendix. Figure 3 , Figure 3 This is a schematic diagram showing the positions of the partition plates and the substrate to be coated in the powder coating device of the present invention. The partition plates 2 are inclined to increase the contact area with the powder and facilitate the adhesion of powder to the edge areas. Two adjacent partition plates 2 form an inverted V-shaped space, and the spray nozzle 1 is located at the top of the inverted V-shaped space. The ends of the adjacent partition plates 2 are connected, and the ends of each partition plate 2 are located on the same horizontal plane, which is parallel to the horizontal plane where the spray nozzle 1 is located, and also parallel to the surface of the substrate 3 to be coated.

[0022] Please see the appendix Figure 4 , Figure 4This is a schematic diagram illustrating the relationship between the powder sprayed from the nozzle of the powder spraying device of the present invention and the limiting effect of the barrier plate. In the powder spraying device of the present invention, the distance between the ends of the barrier plates 2 on both sides of the nozzle 1, i.e., the width of the opening, is less than or equal to the effective width of the spray from the nozzle 1 on the horizontal plane where the ends of the barrier plates 2 are located. The effective width refers to the required spraying precision of the material 3 after the powder in this area covers the surface of the material 3. That is, the powder sprayed through the barrier plates 2 on both sides of the nozzle 1 can directly cover the material 3 to be sprayed and directly meet the spraying requirements without the thinness on both sides. It should be understood that when the nozzle 1 sprays, the sprayed powder is sprayed in a cone shape. Since the present invention has barrier plates 2 on both sides of the nozzle 1, the powder in the unstable area on both sides of the cone-shaped powder is blocked by the barrier plates 2 before contacting the surface of the material 3 to be sprayed, and is directly adsorbed on the barrier plates 2. The powder with a uniform center passes through the end of the barrier plate 2 to spray the material 3, so that the powder covering the material 3 is of uniform thickness. Several spray nozzles 1 and barrier plates 2 are arranged in a straight line, and the ends of the barrier plates 2 are connected to each other, so that the areas covered by each spray nozzle 1 on the board 3 are interconnected, realizing automated and uniform spraying of the entire board 3.

[0023] Example 2: During prolonged spraying operations, the powder adhering to the barrier plate 2 gradually thickens, leading to reduced adhesion. The powder on the barrier plate 2 is easily blown back onto the substrate 3, resulting in reduced powder coverage on the substrate 3. To address this issue, in this example, please refer to the attached document... Figure 5 Appendix Figure 6 , Figure 5 This is a schematic diagram of the powder coating device of the present invention, which includes a barrier plate in the form of a conveyor belt. Figure 6This is a partial schematic diagram of a powder coating device with a barrier plate in the form of a conveyor belt. The barrier plate 2 is a conveyor belt structure driven by a rotating drum. The conveyor belt has two sets of alternating rotating contact surfaces. Compared with a fixed barrier plate 2, its effective contact area is at least twice that of a fixed barrier plate 2, thereby increasing the powder holding capacity. The drive roller shaft of this conveyor belt structure is located on one side of the spray nozzle 1, and the other side is formed by a driven rod to form a vertical V-shaped structure, so that the ends of adjacent conveyor belt barrier plates 2 can be joined together to form a V-shaped structure, thereby reducing the impact on the connection between the coverage areas of two adjacent spray nozzles 1 and avoiding obvious dividing lines. For the conveyor belt type barrier plate 2, for ease of description, the area in direct contact between the conveyor belt and the powder sprayed from the spray gun nozzle 1 is defined as the front area, and the opposite side is the back area. Driven by the drive roller, the front area of ​​the conveyor belt rotates towards the spray gun nozzle 1. On the other side of the conveyor belt that is not opposite to the spray gun nozzle 1, i.e., the back area, a powder scraper 4 is provided. The powder scraper 4 is provided with a scraping groove 41. The edge of the powder scraper 4 is in close contact with the back area of ​​the conveyor belt. As the conveyor belt moves, the conveyor belt and the edge of the powder scraper 4 generate relative movement. The powder on it is separated from the conveyor belt and collected by the powder scraper 4. The conveyor belt with the powder removed re-enters the powder spraying area from the end and re-adsorbs the powder on the conical edge, making the powder spraying device of the present invention suitable for long-term and high-concentration powder spraying operations.

[0024] Please see the appendix Figure 7 , Figure 7 This is a partial cross-sectional schematic diagram of a powder coating device with a conveyor belt-shaped baffle plate. In some preferred embodiments, the powder scraper 4 is a cavity structure with a scraping groove 41. The cavity is connected to a negative pressure mechanism through a pipe. The conveyor belt-shaped baffle plate 2 carrying powder contacts the scraping groove 41 of the powder scraper 4. Under the movement of the conveyor belt, the powder on it is scraped off by the scraping groove 41 and enters the cavity through the opening at the scraping groove 41. The powder in the cavity is sucked out by the negative pressure mechanism and can be recycled, further improving the working time of the powder coating device.

[0025] Example 3; please refer to the appendix. Figure 8 , Figure 8This is a schematic diagram of a partial spraying area of ​​the powder coating device described in this invention. When using the powder coating device to powder coat the sheet 3, the powder sprayed from two adjacent nozzles 1 will overlap after passing through the end of the barrier plate 2. To ensure the continuity of the coating on the sheet 3, the sheet 3 should be located below the intersection point. Therefore, the powder thickness at the overlapping powder position on the sheet 3 may be twice the powder thickness in other areas, severely reducing the uniformity of the coating. In some preferred embodiments, the spraying position of the sheet 3 is exactly at the point where the powder sprayed from two adjacent nozzles 1 just begins to intersect. This avoids overlapping of the powder coating areas. However, this spraying method results in a lack of smooth transition of powder between the two coating areas, which may lead to... After spraying, a clear dividing line is produced. Therefore, in order to solve the problem of the overlapping spraying area, reduce the difference in powder coating thickness between the overlapping spraying area and other spraying areas, and improve the overall uniformity, a negative pressure powder suction port 5 is provided at the end of the barrier plate 2. The negative pressure powder suction port 5 can at least extract the powder between the end of the barrier plate 2 and the board 3. Specifically, in this embodiment, a gap is left between the ends of two adjacent barrier plates 2, and a cavity connected to a negative pressure device is provided at the upper end of two adjacent barrier plates 2. The gap is at least one opening of the cavity, and the gap is the negative pressure powder suction port 5 facing the board 3. Side baffles can be provided next to the barrier plates 2 on both sides to form a corresponding cavity structure, and the ends of the barrier plates 2 form the negative pressure powder suction port 5.

[0026] During the use of the powder coating device described in this embodiment, two adjacent powder coating devices have overlapping powder coating areas on the plate 3. Directly above this area is the negative pressure powder suction port 5 connected to the negative pressure device. Please refer to the attached document. Figure 9 , Figure 9This is a schematic diagram of a powder suction port with a rotatable baffle plate. During powder coating, the negative pressure device provides suction, drawing out some powder from the overlapping powder coating areas through the negative pressure suction port 5, preventing it from settling on the board 3. This reduces the powder thickness in the overlapping coating areas and improves the uniformity of the coating. Furthermore, by adjusting the magnitude of the negative pressure suction, the powder thickness in the corresponding areas can be controlled. It should be understood that during the process of the baffle plate 2 intercepting the powder sprayed from the spray gun nozzle 1, although the powder sprayed from the spray gun nozzle 1 is intercepted by the baffle plate 2, the gas will collide with the baffle plate 2, thereby generating turbulence and rebounding into the central area, causing airflow impact on the powder in the central area, resulting in the powder in the central area becoming disordered and chaotic before reaching the plate 3. The powder that should have been uniformly deposited on the plate 3 also becomes disordered and uneven. However, in the powder spraying device described in this embodiment, since a pressure suction source is provided at the end of the baffle plate 2, the airflow is sucked out of the spraying area from the negative pressure powder suction port 5. Therefore, the airflow that originally collided with the baffle plate 2 is provided with orderly guidance. When the airflow sprayed from the spray gun nozzle 1 collides with the baffle plate 2 to generate high-pressure airflow, and there is a formed negative pressure suction area at the end of the baffle plate 2, the airflow can move orderly along the baffle plate 2 and be sucked out of the spraying system, which greatly reduces the impact effect on the central spraying area and ensures the overall uniformity of the spraying area.

[0027] It should be noted that: In Example 2, a powder scraper 4 with a negative pressure suction cavity is provided. The negative pressure suction cavity used in the powder scraper 4 in Example 2 and the negative pressure cavity in Example 3 can be the same cavity, with the same negative pressure source providing suction; or they can be independent negative pressure sources and negative pressure cavities, so as to facilitate the adjustment of the negative pressure suction intensity according to the respective negative pressure suction intensity requirements.

[0028] Example 4; In some preferred embodiments, the end of the barrier plate 2 near the spray nozzle 1 is a rotatable adjustable end. Specifically, taking the conveyor belt type barrier plate 2 as an example, a rotating motor can be set to drive the entire barrier plate 2 to rotate with the active drive roller shaft of the barrier plate 2 as the axis. At this time, the ends of the barrier plates 2 can move away from each other or move closer to each other, which greatly increases the flexibility of the powder coating device of the present invention. When the ends of the barrier plates 2 move away from each other, that is, the effective spraying area of ​​the spray nozzle 1 is narrowing and the overlapping spraying area of ​​two adjacent spray nozzles 1 is shrinking. In use, the board 3 can be pre-coated and the spraying effect can be observed in real time. According to the spraying effect, the distance between the ends of the barrier plates 2 can be adjusted until the spraying areas of the two spray nozzles 1 just do not overlap, or the width of the overlap does not affect the overall powder coating accuracy. The powder coating device of this Example 4, combined with the negative pressure powder suction port 5 of the powder coating device of Example 3, can greatly improve the adjustment of the powder coating accuracy of the overlapping spraying area.

[0029] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the principle of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A powder coating apparatus, comprising spray nozzles, wherein a plurality of the spray nozzles are arranged at intervals, characterized in that, It also includes a baffle plate, which is disposed between two adjacent spray gun nozzles. The baffle plates on both sides of the spray gun nozzle are symmetrically arranged, and each spray gun nozzle is installed on the same horizontal plane. The ends of two adjacent baffle plates are located on the same horizontal plane, and this horizontal plane is parallel to the horizontal plane where the spray gun nozzle is located. The powder sprayed from the spray gun nozzle passes through the ends of the baffle plates on both sides and can spray the material to be sprayed in a manner that meets the spraying requirements.

2. The powder coating apparatus according to claim 1, characterized in that, The barrier plate is a conveyor belt structure, wherein the surface of the barrier plate in contact with the powder changes cyclically.

3. The powder coating apparatus according to claim 2, characterized in that, A powder scraper is provided in the area where the barrier plate does not contact the powder sprayed from the nozzle, and the powder scraper can scrape the powder on the barrier plate.

4. The powder coating apparatus according to claim 3, characterized in that, The powder scraper is a cavity structure with scraping grooves. The cavity structure is connected to a negative pressure mechanism, which is used to extract powder from the cavity structure.

5. The powder coating apparatus according to claim 1, characterized in that, The barrier plate is provided with a negative pressure powder suction port at its end. The negative pressure powder suction port is facing the plate to be sprayed with powder. The negative pressure powder suction port can suck out the powder from the spraying area.

6. The powder coating apparatus according to claim 1, characterized in that, The barrier plate is provided with a movable adjustment end, which allows the distance between the ends of adjacent barrier plates to move closer or further apart.

7. The powder coating apparatus according to claim 1, characterized in that, The powder sprayed from two adjacent nozzles of the spray guns crosses outside the barrier plate.

8. The powder coating apparatus according to claim 7, characterized in that, The surfaces of the panels to be sprayed should not exceed the intersections.

Images