The compressed air used for powder electrostatic spraying is basically the same as the compressed air used for liquid paint spraying. It needs to be a clean gas without oil, water and other impurities after passing through the oil-water separator, and has a regulating valve device for adjusting the changing pressure. At present, there is no unified compressed air technical index dedicated to plastic spraying construction. Some technical data quoted below are the aerospace industry standard QJ2507-91 coating quality control and are for reference only.
Gas pressure: Although the air source sent by the compressed air station or the self-contained compressed air pump has been filtered once, it should be filtered by the oil-water separator again when it enters the powder electrostatic spraying room, and then filtered in the oil-water separator. An air filter pressure reducer is installed at the outlet, so that the gas pressure when entering the powder Spray Gun can be freely adjusted to a pressure suitable for powder spraying of about 0.1MPa through the pressure reducer.
Oil content: No more than 8mg/m 3 (6.4x10-6) before .
Dust particle size: The size of the raw particles in the air filter should not be larger than 2µm. And there should be no harmful gases or vapours.
In order to verify these theoretical requirements, the following simple methods can be used for configuration: adjust the gas pressure to 0.3~0.4MPa, take the filter paper and place it in the vertical position of the gas flow (to be fixed), at a distance of 100mm, and then turn on the gas Source valve. Let the airflow rush to the filter paper, blow continuously for 2 minutes, close the valve, check the filter paper, if there are no wet spots, oil stains and other sundries, it should be a qualified gas, otherwise, it needs to be improved before it can be used for dusting.