During decarburization procedures the vacuum system needs to operate long time in a rough pressure range. An efficient gas-cooling is essential as the extracted 
incredibly hot gases would or else overheat the filter and vacuum program.
With the development of technology and the improvement of product quality in aerospace, electric power, iron and steel digesting, pharmaceutical and chemical industries, these industries need to obtain a certain vacuum environment. Simultaneously, the vacuum system used by these industries is continuously increasing, and the vacuum level is continuously increasing. Furthermore, the state’s environmental safety, energy conservation and three wastes discharge to the above-talked about industries, etc. The requirements are more stringent. At the Gas-Cooling Roots Pump china moment, the existing dry vacuum pumps available, such as screw vacuum pumps and claw vacuum pumps, cannot meet the requirements of oil-free large pumping velocity clean vacuum environment proposed by these industries because of the restrictions of pumping velocity 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 supply an all-gas-cooled vacuum system to fulfill the use in a clean vacuum environment with large oil-free pumping speed.