... casing ensures reliable running with low noise under the high pressure condition.2.4Precision harden-teeth-surface helical timing gears without ... to use and maintenance .3.Roots blower Performance dataBore:50-250mm Pressure rise:9.8~98Kpa Flow capacity:0.6~113m³/min ... inlet silencer with filter,outler silencer,pully,belts,belts cover,pressure release valve, check valve,flexible joint,pressu-re gauge, ...