How to prevent static electricity accidents during the painting process of automobile factories
During the spray painting process of automobile manufacturers, the air often contains a large amount of flammable gases volatilized from paints, thinners and solvents. Although it is equipped with a ventilation device, the exhaust air volume often fails to meet the requirements, and these flammable gases may reach the explosive limit. If electrostatic discharge generates electric sparks, it is very easy to cause combustion and explosion. Especially in the work site, it is inevitable that there will be a lot of spray paint scattered, and there is paint dirt everywhere in the exhaust pipe on the workbench, if it catches fire, the fire will spread rapidly.
When spraying paint, paint and its thinner are all substances with high resistivity, which are easy to generate and accumulate static electricity. The paint has a fast flow rate in the pipeline. When spraying, the paint is sprayed from the small holes of the spray gun with compressed air. The working pressure of the air pump is generally 3 to 4 kgf/cm2. The flow rate of the spray paint in the pipeline is generally above 3 m/sec. So fast, it is easy to generate static electricity.
The spray gun, human body, and workpiece are insulated from the ground, and static electricity is not easy to conduct away. Although the spray gun used for painting is made of metal, it is connected to the air pump through a plastic hose or a rubber hose and is also insulated from the ground. Workers holding spray guns generally wear rubber-soled work shoes with strong insulation, which are also insulated from the ground. If the workpiece to be sprayed is a non-metallic body, or although it is a metal material, but has other supports, backing plates, and poor conductivity, these will accumulate static electricity.
In order to prevent static electricity from accumulating and causing fires, the spray gun should be equipped with static elimination devices, such as good grounding devices; operators should wear anti-static shoes with low resistance; when spraying non-metallic workpieces, the continuous spraying time should not exceed one and a half minutes bell. The spraying workshop must be well ventilated to reduce the accumulation of flammable gas in the air; the scattered paint must be removed frequently. Without affecting the quality, spray water in the spraying workshop to increase the indoor air humidity and reduce the accumulation of static electricity. The amount of paint stored in the workshop should not be too much, and generally should not exceed the amount used in one shift.