The pollution of painting production line generally includes waste gas, waste water, waste residue and noise. At present, the exhaust gas of coating production line in our country mainly comes from the exhaust gas of pretreatment, spraying room, leveling room and drying furnace, and the pollutants discharged are mainly as follows: organic solvents that can form photochemical smog, volatile matter discharged from odorous coatings, thermal decomposition products and reaction products, acid-base fog and shot peening. Dust and dust in paint mist. The most effective way to solve the pollution of organic solvents is to use coatings without organic solvents or with low content of organic solvents, to minimize the amount of organic solvents, to reduce the amount of organic solvent waste gas treatment, to centralize the waste gas containing high concentration of organic solvents, to take dilution and discharge to the atmosphere; to dry the production line. The organic solvent exhaust gas with high concentration and low air volume from solidification furnace is usually treated by combustion method, catalytic combustion method and adsorption method.
The wastewater mainly comes from degreasing, phosphating, passivation wastewater and electrophoretic paint-containing wastewater produced by cathodic electrophoresis. The water-borne paint spraying room and the waste water from cleaning, and the waste water from the recycling water of the paint spraying room are discharged regularly. Generally, all wastewater is concentrated in basement and treated separately according to the type of wastewater. The wastewater containing acid and alkali is neutralized, precipitated, filtered and discharged; the wastewater containing 6-valent chromium (Cr6-) is treated by electrolysis and chemical reduction; the wastewater of spraying room, whether water-borne paint or solvent-based paint, is treated by adding paint mist coagulant, the paint residue is discharged automatically, and the treated wastewater continues. Recycling, burning of paint residue or disposal with other industrial wastes.
Motor assembly line
Coagulant iwaterA is mostly composed of cationic polymers with medium molecular weight. It has a very high charge and has a strong attraction to the paint droplets. When the paint droplets are "captured" and adsorbed, it completely wraps the paint droplets with different affinity, penetrates the paint droplets, destroys the functional groups of the paint, and completely eliminates the stickiness. Drive the broken paint droplets to float. Paint mist coagulant iwaterB is mostly composed of polymers with molecular weight of tens of millions. Through the "bridge" action between molecules, the damaged paint mist and impurities are aggregated into larger groups to make them firm and bond, and enhance the efficiency of mechanical dehydration. The flocculant can also neutralize the system charge, keep the ion balance in the system, and the molecular weight is larger, which makes the flocculant group float faster in the system, and form paint slag floating on the water surface.
Waste residue is mainly lacquer residue and sediment from wastewater treatment. It can be dewatered by plate and frame filter press and transported to special waste residue storage area.
Noise sources mainly come from fans and transport devices, so we must choose fans and transport devices that meet the noise requirements on the production line. It is better to set up sound-absorbing materials inside the painting workshop. With the development of the times, the control system of motor assembly line has been improved continuously, which requires the control system to be more and more reliable. Therefore, the electrical control of painting production line is generally double-control, which can be controlled by each electrical cabinet or by the central room. The central control room and the drying channel are generally equipped with a computer, which can accurately control the temperature of each zone of drying and curing furnace body. The central control room can set up a TV monitor to display and record the temperature curve of rise and fall, and it can also set up a computer to control the temperature of drying and curing furnace body accurately. Set and modify parameters at any time, so as to adjust the temperature according to the size of various workpieces and painting color. The tank liquid can be controlled by a thermocouple. Generally, all motors on the coating production line are equipped with double protection and interlock with the main control. If any motor fails, the sub-control cabinet and the central control room can alarm. If the equipment fails, the whole line can stop automatically to ensure safe operation.