Practice has proved that the Roots fan is the most economical and stable meltblown gas source equipment. Air compressor pressure is too high, the second is the work process requires oil lubrication, even if the claimed "oil-free" air compressor, but only in the internal oil and gas separator, there will still be a small amount of oil mist with the airflow out, resulting in meltblown cloth odor, made into a mask odor is obvious, resulting in the test does not meet the standards. From the situation of 250 production lines matched by Jinkong to customers, more and more production lines are using Roots blowers instead of air compressors.