The method to solve the recovery of over-sprayed powder in electrostatic powder spraying


Powder electrostatic spraying will produce a large number of unadsorbed powder. These powders will cause pollution to the surrounding air.

At present, there are two main types of powder recovery: cyclone separation and filtration.

[Recovery of powder coating powder] The solution to the recovery of powder overspray in powder electrostatic spraying

Electrostatic powder coating is a method of using the coating under the action of high voltage electrostatic induction, under the action of electric field force to make the powder coating powder evenly adsorbed on the surface of the coated workpiece, and then through melting leveling and curing film to achieve the purpose of coating. During the coating process, a large amount of unadsorbed powder will be produced, which will cause pollution to the surrounding air. At present, there are two main types of powder recovery: cyclone separation and filtration.

1, the cyclone separation recovery device is to make the powder flow rotating movement, under the action of centrifugal force, to achieve the purpose of powder coating powder and air separation. According to the different structure of cyclone separation powder recovery device, its powder recovery rate can reach 80 ~ 90% in general. In order to meet the environmental requirements, separation of fine powder particles, to ensure the clean discharge of air, in the cyclone separation recovery device discharge end need to add a secondary filtration device.

2. The filter powder recovery device is to pass the powder air through the filter material with certain micropores to achieve the purpose of gas and solid separation. However, the disadvantage is that the micropores in the filter material are easy to be blocked, resulting in the reduction of the recovery air flow and the reduction of the recovery effect. In order to overcome this shortcoming, a pulse-back blowing filter device was developed, which used pulse-back blowing to periodically clean the particles adsorbed in the micropores of the filter material to keep the air flow smooth and maintain a constant recovery effect. According to the size of the powder particles, the powder recovery rate can generally reach 98% by selecting the appropriate filter element material. In the process of powder electrostatic spraying, most of the pulse blowback filter devices are used, but because of the requirements of powder and color change, it is necessary to clean the spray chamber and recovery system, resulting in a large amount of waste powder spillover during cleaning, resulting in pollution.

The recovery device of over-sprayed powder in powder electrostatic spraying is composed of a first-stage whirlwind separation device, an automatic discharge valve and a second-stage pulse back-blowing filter element filtration recovery device. Level of cyclone separating device connected to spray chamber entrance, the settlement of level of cyclone separating device room and automatic unloading valve connection, primary cyclone separating device outfalls and secondary back pulse filter recovery unit inlet connection, secondary back pulse filter cartridge recycling equipment export through air duct connected to the induced draft fan. The utility model has the advantages of improving the automation degree of powder painting process, improving the effective utilization rate of powder, reducing the powder pollution to the atmosphere during the powder painting process and cleaning the spray room, greatly reducing the labor intensity of powder painting process, and significantly improving the labor productivity of painting.

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