During decarburization procedures the vacuum system must operate very long time in a tough pressure range. A competent gas-cooling is necessary as the extracted popular gases would otherwise overheat the filter and vacuum system.
With the development of technology and the improvement of item quality in aerospace, energy, iron and steel digesting, pharmaceutical and chemical industries, these industries have to obtain a particular vacuum environment. Simultaneously, the vacuum system used by these industries can be continuously raising, and the vacuum degree is 
continuously increasing. Moreover, the state’s environmental protection, energy saving and three wastes discharge to the above-described industries, etc. Certain Gas-Cooling Roots Pump requirements are more stringent. At present, the prevailing dry vacuum pumps in the marketplace, such as for example screw vacuum pumps and claw vacuum pumps, cannot meet up with the requirements of oil-totally free large pumping acceleration clean vacuum environment proposed by these industries because of the restrictions of pumping quickness characteristics and structural mechanism.
Because of the shortcomings of the existing technology, the technical problem to be solved by the utility model is to provide an all-gas-cooled vacuum system to satisfy the utilization in a clean vacuum environment with huge oil-free pumping speed.