During decarburization procedures the vacuum system needs to operate long time in a tough pressure range. An efficient 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 digesting, pharmaceutical and chemical industries, these industries have to obtain a certain vacuum environment. Simultaneously, the vacuum system used by these industries can be continuously increasing, and the vacuum degree is continuously increasing. Moreover, the state’s environmental protection, energy conservation and three wastes discharge to the above-pointed out industries, etc. The 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 velocity clean vacuum environment proposed by these industries because of the restrictions of pumping acceleration characteristics and structural system.
In view of the shortcomings of the prevailing technology, the Gas-Cooling Roots Pump technical problem to be solved by the utility model is to supply an all-gas-cooled vacuum system to satisfy the utilization in a clean vacuum environment with huge oil-free pumping speed.