100% copper motor ring air blower pump 
Freesea Blower Series:

HR series side channel blowers with their high inlet volume flow up to 2500m³/h and a differ entail pressure up to 780mbar, they are reliable, low-maintenance and durable and are the first choice for many applications. When used with a frequency converter together, the performance can be increased considerably 2HR series side channel blower feature voltage range motors for 50HZ and 60HZ in protection class IP55(insulation classF), the 2HRseries side channel blower can be used without any modifications or tests in Europe, America and Asia.Centrifugal circulation design, high pressure, big wind power, air amortize design,even lower noise, 
lubricate without oil design, purer air, high efficiency, big range collocate, and long time use.

Operating principle of side channel blower : 

The impellers in the 2HR-series machines are mounted directly on the motor shaft for noncontact compression entirely without friction.Maximum operational reliability,even at high differential pressures.is ensured by the arrangement of the bearings outside the compression chamber.