Powder coating device

Abstract

To provide a powder coating device that removes only fine powders that are difficult to attach to a coated object from a recovery powder circulation path, suppresses a ratio of fine powders contained in recovery powders, and has high adhesion efficiency.SOLUTION: A powder coating device performs coating by blowing a powdered paint A conveyed by conveyance air from a coating material tank 1 to a coated object W in a powder coating booth 6, and comprises a circulation path that recovers overspray powders which have not attached to the coated object W and returns the recovered recovery powders to the coating material tank 1. In the powder coating device, a fine powder removal device for removing fine powders which are difficult to adhere to the coated object is installed in the recovery powder circulation path.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a powder coating device that sprays powder paint from a paint tank onto an object to be coated from a paint gun in a coating booth and is equipped with a recovered powder circulation path that collects overspray powder that does not adhere to the object to be coated and transports it to the paint tank. [Background technology]

[0002] As shown in Figure 2, the powder coating device sucks powder paint A from a paint tank 20 using an injector 21 that supplies compressed air, and transports the powder paint A via a paint hose 22 to a paint gun 23, where the compressed air supplied to the injector 21 is converted into carrier air.The powder paint A is then sprayed from the paint gun 23 onto an object to be coated W, causing the powder paint A to adhere to the object to be coated W by electrostatic force.

[0003] Conventionally, in this type of powder coating apparatus, powder paint A that does not adhere to the workpiece W in the coating booth 24 is sucked into and collected by a bag filter collection device 25. The recovered powder collected by the bag filter collection device 25 is air-transported to a mini-cyclone 28 via a transfer hose 27 by an injector 26 installed in the bag filter collection device 25, and after the recovered powder is separated from the transport air by the mini-cyclone 28, debris C mixed in with the recovered powder is removed by a screening device 29 equipped with a vibrating sieve, and the powder is returned to the paint tank 20 for reuse (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-159248 [Patent Document 2] Patent No. 3429314 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] In conventional powder coating equipment, the collected powder, including fine powder, is continuously reused by an air circulation mechanism in which the bag filter recovery device 25 and the mini cyclone 28, and the paint tank 20 and the mini cyclone 28 are each connected to a degassing mechanism.

[0006] However, if the recovered powder containing fine particles is continuously reused, the proportion of fine particles in the recovered powder that are difficult to adhere to the workpiece W increases, resulting in a decrease in the coating efficiency on the workpiece B and an increase in the defective rate.

[0007] SUMMARY OF THE INVENTION The present invention aims to provide a powder coating apparatus that removes only fine powder from the circulation path of the recovered powder, thereby reducing the proportion of fine powder contained in the recovered powder and achieving high deposition efficiency. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a powder coating apparatus in which powder paint transported from a paint tank by conveying air is sprayed onto an object to be coated in a powder coating booth, overspray powder that does not adhere to the object to be coated is collected, and the collected powder is returned to the paint tank through a circulation path, and the apparatus is characterized in that a fine powder removal device is installed in the circulation path for the collected powder to remove fine powder that does not adhere to the object to be coated.

[0009] The fine powder removal device can be composed of a mini-cyclone that separates the recovered powder to be returned to the paint tank from the fine powder in the recovered powder, and a dust collector that collects the fine powder separated by the mini-cyclone.

[0010] The mini-cyclone also includes a degassing mechanism that releases the negative pressure generated by the dust collector to the atmosphere to adjust the pressure. [Effects of the Invention]

[0011] According to the powder coating device of this invention, fine powder that does not easily adhere to the object to be coated can be removed from the circulation path of the recovered powder of the powder paint, thereby reducing the proportion of fine powder contained in the recovered powder, increasing the adhesion efficiency, and not only reducing defective products but also leading to a reduction in industrial waste. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing a circulation path of collected powder in a powder coating apparatus according to the present invention. [Figure 2] 1 is a schematic diagram showing a circulation path of collected powder in a conventional powder coating device. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a powder coating apparatus according to the present invention will now be described with reference to the accompanying drawings.

[0014] As shown in Figure 1, the powder coating device of this invention is a device in which powder coating material A in a paint tank 1 is sucked in by an injector 2 to which compressed air is injected, and the compressed air injected into the injector 2 is converted into carrier air and transported to a coating gun 4 via a paint hose 3. The powder coating material A is then sprayed from the coating gun 4 onto an object to be coated W, where it adheres to the object to be coated W by electrostatic force.

[0015] The object to be coated W is suspended and supported by a transport conveyor 5 and transported through the painting booth 6 from the entrance side to the exit side, and while being transported, powder paint A is sprayed onto the object to be coated from an electrostatic painting gun 4 installed in the painting booth 6. The painting gun 4 is installed so that it can move up and down by a reciprocator 7.

[0016] In the painting booth 6, overspray powder that does not adhere to the workpiece W is supplied to a bag filter collection device 8 via a collection duct 7, which separates the collected powder from the air. The collected powder is then air-transported to a mini cyclone 11 via a conveying hose 10 by an injector 9 installed below the bag filter collection device 8, and is then separated into the collected powder and the conveying air by the mini cyclone 11.

[0017] A sieve-type screening device 13 is connected to the discharge outlet of the mini-cyclone 11, and dust C mixed in with the recovered powder is removed.

[0018] The recovered powder that has passed through the screening device 13 is sent to the paint tank 1 via a flexible tube 14.

[0019] The paint tank 1 that supplies the powder paint to the paint gun 4 has a perforated plate at the bottom, and dehumidified and oil-free compressed air is supplied from below the perforated plate, keeping the powder paint inside in a fluid state and preventing the formation of clumps of powder paint.

[0020] The upper part of the mini cyclone 11 is connected via piping 17 to a dust collector 16 that collects dust using the negative pressure of a blower 15, and from the recovered powder air-transported to the mini cyclone 11, fine powder D that does not easily adhere to the object to be coated W is removed by the dust collector 16.

[0021] The mini cyclone 11 is provided with a hood-shaped deaeration mechanism 12 at the top that is connected to the atmosphere, and this deaeration mechanism 12 adjusts the negative pressure in the dust collector 16, sending only fine powder D that does not easily adhere to the workpiece W to the dust collector 16, thereby efficiently removing the fine powder D that does not easily adhere to the workpiece W.

[0022] Furthermore, the paint tank 1 that supplies the powder paint to the paint gun 4 is a fluidized type that is supplied with compressed air from below as described above, so fine powder D that does not easily adhere to the workpiece W also gathers in the upper part of the paint tank 1. For this reason, a hood-shaped deaeration mechanism 18 that is open to the atmosphere is provided above the paint tank 1, and this deaeration mechanism 18 is connected to the piping 17, and the fine powder D that has risen up inside the paint tank 1 is also removed by the dust collector 16 while adjusting the negative pressure.

[0023] The present invention is not limited to the above-described embodiments, and can of course be embodied in various other forms without departing from the spirit of the present invention. The scope of the present invention is indicated by the claims, and further includes the meaning of equivalents set forth in the claims, and all modifications within the scope of the claims. [Explanation of symbols]

[0024] 1 paint tank 4 paint guns 6 Powder Coating Booth 11 Mini Cyclone 12,18 Degassing mechanism 16 Dust collector A Powder paint D Fine powder

Claims

1. This powder coating device is equipped with a circulation path that sprays powder paint transported by conveying air from a paint tank onto an object to be coated in a powder coating booth, collects overspray powder that does not adhere to the object to be coated, and returns the collected powder to the paint tank, and is characterized in that a fine powder removal device is installed in the circulation path for the collected powder to remove fine powder that does not easily adhere to the object to be coated.

2. 2. A powder coating apparatus according to claim 1, wherein the fine powder removal device comprises a mini-cyclone for separating the recovered powder to be returned to the paint tank from the fine powder in the recovered powder, and a dust collector for collecting the fine powder separated by the mini-cyclone.

3. 3. A powder coating apparatus according to claim 2, wherein said mini-cyclone and said paint tank are provided with a deaeration mechanism for adjusting the negative pressure generated by said dust collecting device by releasing it to the atmosphere.

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