Practice has proved that Roots blower is the most economical and stable melting jet source equipment. One is that the pressure of the air compressor is too high, and the other is that the working process needs oil lubrication. Even if the so-called "oil-free" air compressor is only equipped with an oil-gas separator, there will still be a small amount of oil mist ejected with the airflow, which will lead to the odor of the meltblown cloth and the obvious odor of the mask, which will lead to the failure of detection. Judging from the 250 production lines provided by Gong Jin to customers, more and more production lines are replacing air compressors with Roots blowers.