During decarburization processes the vacuum system must operate very long time in a tough pressure range. An efficient gas-cooling is necessary as the extracted warm 
gases would otherwise overheat the filter and vacuum program.
With the development of technology and the improvement of item quality in aerospace, energy, iron and steel digesting, pharmaceutical and chemical industries, these Gas-Cooling Roots Pump industries have to obtain a particular vacuum environment. Simultaneously, the vacuum system utilized by these industries is usually continuously increasing, and the vacuum degree is continuously increasing. Furthermore, the state’s environmental security, energy conservation and three wastes discharge to the above-stated industries, etc. The requirements are more stringent. At the moment, the existing dry vacuum pumps on the market, such as for example screw vacuum pumps and claw vacuum pumps, cannot meet the requirements of oil-totally free large pumping swiftness clean vacuum environment proposed by these industries due to the restrictions of pumping quickness characteristics and structural system.
Because of the shortcomings of the existing technology, the technical problem to be solved by the utility model is to supply an all-gas-cooled vacuum system to satisfy the use in a clean vacuum environment with huge oil-free pumping speed.