Discussion on the present situation and development of coating equipment production line in China

Coating production line equipment in our country began to develop since 70s, especially after the reform and opening up, the rapid development, but basically is in a "spontaneous" state, the domestic powder coating equipment does not meet the market demand, many key spraying equipment or to introduce more. Estimation of existing coating production lines in China thousands of above, and every year hundreds of investment in new production lines, the annual investment of about billion yuan, foreign sales of products and the company's share reached 30% - 40%; China's total 1000 coating equipment factory, domestic products now covers almost all department of coating industry.

The so-called coating refers to the metal and non-metallic surface covering protective layer or decorative layer. With the development of industrial technology, powder coating equipment coating has been developed by hand to the direction of industrial automation, and automation degree is more and more high, so the application of coating production line is more and more widely, and deep into many fields of the national economy.

1. as a pretreatment technique, the traditional method of initial pretreatment is trough leaching, which is impregnated by process. With the improvement and development of the process, the "two in one" (oil removal, rust removal) and three in one (i.e. oil removal, rust removal, passivation) process have appeared. At present, foreign and domestic appliance industry by spraying pretreatment, which is characterized by high production efficiency, simple operation, easy to realize automation or semi automation, good degreasing effect, phosphating film is compact and uniform. But no matter what, surface pretreatment is a must, according to the requirements of different coating and corrosion resisting requirements of removing oil and rust, phosphating treatment method to the workpiece to be raw material conditions to choose. Of course, in the pretreatment process, sandblasting, shot blasting or grinding process also in different sectors of different sectors, according to the needs of choice of applications. The development of surface treatment technology in development, it is the first general use of tap water washing, but with the requirements of technology and development, now has been washed with distilled water or pure water; pretreatment is treated by ultrasonic technology.

2. as a drying curing process, there are generally hot air circulation and radiation heating type. In 50s and 60s, the main steam or electric heater as a heat source for drying and curing, from 60s began to appear in 70s infrared drying, far infrared drying and microwave drying, in 1994 there have been rapid infrared heating technology. With the uniform requirements for drying temperature control and temperature control requirements, appeared in the furnace for hot air circulation, the late 80s fuel (gas) hot air circulation drying oven (curing furnace), fuel (gas) and hot air drying (curing) is widely used in general, the current domestic use; the electric heating hot air drying furnace is more, but the electricity as a method of baking heat source is often not an economy, especially the capacity fee burden, the construction investment increases; but the design and operation of electric heating is relatively simple and convenient operation, so the application is still relatively small in in drying furnace. The use of fuel (gas) method to replace the heating electric baking is a major energy saving technology, with the domestic industrial development, fuel (gas) supply has been basically solved or are easy to solve, such as the rated heating per hour to design large drying furnace hundreds of thousands to millions of calories by electric heating and drying, the operational cost of fuel heating furnace the difference of 3 - 5 times, so in the production line, can be applied. But because China's energy structure dominated by coal, determines a considerable portion of China area and industry in the future energy use, still depends on the development and utilization of coal, especially the geographical environment and economic developed regions, so we adopt coal combustion as the heat source, the heat pipe heat exchanger as new technology is the development of pulverized coal heating furnace (dry curing). The kiln adopts fully closed structure and unique set of dust emission burner, dust collector, and pulverized coal combustion does not affect the basic working environment, clean air around the furnace, almost no dust, greatly improving the operating environment. All the indexes meet the requirements of urban environmental protection.

3. in order to make the air in the dust coating production line has been effectively controlled, should first improve the production line environmental conditions, separate grinding, clean process and painting process, to avoid grinding generated dust into the production line or dry spraying room (curing) furnace, eliminate grinding dust on the spraying effect; secondly, shall regularly replace the air filter, which can effectively remove the dust in the air. In recent years, with the strict environmental protection requirements, waterborne coatings, high solid coatings, powder coatings and other environmentally friendly coatings have been developed rapidly. According to reports, China's annual output of powder coatings has reached 60 thousand T, second only to the United States, Italy and Germany, ranking fourth in the world. Since 80s, China has successively introduced more than 500 powder coating production lines, and according to the current situation, it should be said to have reached saturation. And how to speed up the localization of powder coating equipment has become an imminent topic in China's painting industry.

4. wastewater mainly comes from degreasing, phosphating and passivation wastewater produced by coating pretreatment, and wastewater containing electrophoretic paint produced by cathodic electrophoresis. Painting room and cleaning waste water produced in aqueous paint, waste water discharged from circulating water of paint and painting room periodically. In general, all waste water is concentrated in the basement and treated separately according to the type of sewage. Neutralization, filtration, and discharge of wastewater containing acid and alkali; wastewater containing 6 valent chromium (Cr, 6-) was treated by electrolysis and chemical reduction