In order to disperse the powder coating better after being sprayed out from the electrostatic powder Spray Gun, two structural methods are mainly adopted at present.
(1) Secondary air pole needle type
It is a Spray Gun that controls the powder dispersion state by increasing or decreasing the pressure of the secondary air, and its structure is shown in Figure 6-17. The powder coating is supplied from the central main pipeline, the compressed air enters from the side, and the secondary air is dispersed at the Spray Gun head. The electrode needle is in the middle, and the powder is charged through the tip corona discharge. Divided into ordinary type, corona enhanced type, flat mouth type and so on. It has the advantages of large air volume and long spray distance, but the chargeability of the paint is poor, and the pattern needs to be adjusted by air.
(2) Reflective plate type
It is by adjusting the position of the reflector to make the ejected powder and air impact the reflector to control the amplitude of the jet stream, and its structure is shown in Figure 6-18. The discharge electrode of the Spray Gun is on the sharp edge of the Spray Gun wall, and there is a disc-shaped reflector in the middle. After the powder is sprayed from the middle along the wall, it is charged through the sharp-edged corona discharge, dispersed and further charged after passing through the charged reflector. onto the object to be coated. It changes the spray pattern by adjusting the distance between the reflector and the discharge electrode. It has the advantages of high charge rate, large spray pattern range and good dispersion, but the spraying distance is relatively short, which is suitable for large-area spraying.
