1. The exhaust of the spray room in order to maintain the working environment of the spray room, the ventilation speed should be controlled within the range of (0.25 ~ 1) m/s according to the provisions of the Labor Safety and Health law. The exhaust of the general spray room is large air volume, the concentration of solvent vapor is very low (its volume fraction is roughly in the range of 10-3% ~ 2×10-'%). In addition, the exhaust of the spray room also contains part of the paint mist produced by spraying.
The particle size of this dust (lacquer fog droplets) is about (20 ~ 200) μm or so, no large wind flying far away, and cause a nearby public hazard, but also become an obstacle to waste gas treatment, these must be paid attention to.
2. The function of air drying room exhaust air in the room is to make the coating in the painting, drying or forced drying before, so that part of the solvent in the film smooth volatilization and the formation of a good film, generally is the extension of the painting room process, in this exhaust contains only solvent vapor, and almost no spray paint mist.
3. Exhaust from the drying room Exhaust gas discharged from the drying room, including exhaust from the paint system and fuel system. The former contains the residual solvent in the coating film not evaporated in the spray chamber and the drying chamber, part of the volatile components such as plasticizer or resin monomer, thermal decomposition products, reaction products. The latter is used as a heat source for fuel combustion exhaust gases. Its composition varies with fuel, such as burning heavy oil, containing a considerable amount of sulfur on the production of sulfite gas, when the furnace temperature is low, operation adjustment and poor maintenance and management, due to incomplete combustion and smoke. The use of gas fuel, although the fuel cost is high and the combustion exhaust gas is relatively clear, there are low equipment cost, easy maintenance, high thermal efficiency advantages. Where electricity and steam are used as heat sources in the drying room, exhaust gases from the fuel system are not considered.
