? ? Early industrial cleaning agent to gasoline, kerosene, but its flammable, explosive characteristics, to the use of great safety risks and inconvenience. In addition, the lack of oil resources in our country further limits the use of such cleaning agents. Later, the preferred cleaning agent is ODS cleaning agent. ODS are mainly substances containing trichlorotrifluoroethane (CFC-113), carbon tetrachloride (CCl4), perfluorocarbons (CFC), total bromoalkanes, bromofluorocarbons and other substances that have destructive effects on the ozone layer.

? ? ?To protect the ozone layer, the international community formulated the Vienna Convention for the Protection of the Ozone Layer in 1985 and the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987. My Government acceded to the Vienna Convention in December 1989 and the Montreal Protocol in June 1991. According to the "China's Overall ODS Elimination Plan for Cleaning Industry" approved by the UN Multilateral Fund Executive Committee in March 2000, China has eliminated all ODS products in 2020.

? ? With the strengthening of the public awareness of environmental protection, but also in order to better protect our living environment, the environmental harmlessness of cleaning agent has been widely concerned by the society. Therefore, the development of new environmental protection, no pollution, low cost "green" cleaning equipment and cleaning methods have become the inevitable development trend and competition conditions of the cleaning industry.

? ? ?At present, a considerable number of domestic machinery and equipment production and processing enterprises and equipment maintenance and repair enterprises still mainly use cleaning gasoline, aviation kerosene and other cleaning media in the process of machinery and equipment processing, maintenance and repair. This kind of cleaning medium not only has the safety hazard of causing fire and explosion in the cleaning process, but also seriously polluted the natural environment and brought potential occupational hazards to the operators. Gasoline and kerosene have very fast volatilization characteristics, and machining, equipment maintenance, repair and other work is generally carried out in the indoor workshop. The high volatility inevitably leads to an increase in the concentration of organic solvents such as gasoline in the air in the workshop, which can be inhaled by operators into the respiratory tract. If workers work in such a working environment for a long time, their health will be affected, especially the central nervous system will be damaged, workers will appear dizziness, headache, weakness, insomnia and other adverse reactions, which will affect the occupational health of workers.

? ? The development of cleaning medium with moderate volatilization, non-flammable and no occupational health hazards is an inevitable development trend in cleaning industry to replace existing organic solvents such as gasoline and kerosene. Dry ice cleaning technology is the most efficient, thorough, fast, safe and environmentally friendly cleaning method because it uses carbon dioxide as the cleaning medium. It is bound to be widely used faster and faster in the future.

? ? Generally speaking, there are the following problems in the current industrial cleaning: (1) low cleanliness: the existing cleaning operation can not realize the thorough cleaning of pollutants, and the residual pollutants have an impact on the performance of the product. (2) Low operational efficiency: Due to the low decontaminating capacity of current cleaning agents, the cleaning process of components takes up a lot of time, extending the delivery time of products. In addition, the low cleaning efficiency increases the labor intensity of the front-line operators. (3) Low safety: gasoline or kerosene is flammable and explosive, and the safety risk of cleaning workplaces is very big. In the past two years, there have been a number of fires and explosions during cleaning operations, resulting in damage to facilities and injuries. (4) Great hidden danger of rust: gasoline or kerosene in addition to flammable and explosive, in use will lead to condensation on the surface of the workpiece, accelerate the surface rust of the workpiece.