... , windproof, rainproof and dustproof5. Newly punch forming fan blade, reasonable angel and reach the max. air flow, ... test, vibration test, concentric performance test, fan blade turning speed test, input air test and vehicle efficiency test9. ... heavy hammer and centrifugal exhaust fanModelStandardBlademmBlade Speed Round/minMotor Speed Round/minCapacitym3/hPressurePaNoiseDBPowerWVoltageVSize (mm ...