... *450*570Features: 1 positive displacement blower, no compression, air conveying is smooth, there is small flow rate changes ... synchronous hard-toothed surface gears ensure long life. 6 much cleaner with no oil Usage: sewage treatment, flour, aquaculture, ... electric power and cement industries etc.Accessory: suction silence (with air filter). Discharge silence, safety valve, pressure gauge, cock, ...