During decarburization procedures the vacuum system needs to operate very long time in a tough pressure range. An efficient gas-cooling is essential as the extracted popular gases would otherwise overheat the filter and vacuum program.
With the development of technology and the improvement of product quality in aerospace, energy, iron and steel digesting, pharmaceutical and chemical industries, these industries need to obtain a specific vacuum environment. At the same time, the vacuum system used by these industries is definitely continuously increasing, and the vacuum level is continuously increasing. Moreover, the state’s environmental security, energy conservation and three wastes discharge to the above-described industries, etc. Certain requirements are more stringent. At present, the existing dry vacuum pumps out there, such as screw vacuum pumps and claw vacuum pumps, Gas-Cooling Roots Pump china cannot meet the requirements of oil-free large pumping acceleration clean vacuum environment proposed by these industries because of the restrictions of pumping velocity characteristics and structural system.
Because 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 satisfy the use in a clean vacuum environment with large oil-free pumping speed.