During decarburization Gas-Cooling Roots Pump processes the vacuum system must operate long time in a tough pressure 
range. A competent gas-cooling is necessary as the extracted hot gases would otherwise overheat the filter and vacuum program.
With the development of technology and the improvement of item quality in aerospace, electric power, iron and steel processing, pharmaceutical and chemical industries, these industries have to obtain a certain vacuum environment. At the same time, the vacuum system used by these industries is usually continuously raising, and the vacuum degree is continuously increasing. Moreover, the state’s environmental security, energy saving and three wastes discharge to the above-described industries, etc. Certain requirements are more stringent. At the moment, the existing dry vacuum pumps out there, such as for example screw vacuum pumps and claw vacuum pumps, cannot meet up with the requirements of oil-free large pumping quickness clean vacuum environment proposed by these industries due to the restrictions of pumping acceleration characteristics and structural system.
In view of the shortcomings of the prevailing technology, the specialized problem to be solved by the utility model is to provide an all-gas-cooled vacuum system to fulfill the utilization in a clean vacuum environment with large oil-free pumping speed.