[martin417]

It is very unlikely that you will get enough suction (delta P) by direct driving an impeller with a CIM. We geared our impeller up 3:1 (the impeller turns 3 times as fast as the CIM motor) to get the necessary rpm. Also, you might look for a different impeller than the one pictured. That is a mixed flow (both axial and radial flow) impeller like what you might see in a turbocharger. This design is a compromise between flow and pressure. What you want is a pure radial flow impeller like you would find in a shop vac. Volume flow rate is not very important, you want to maximize pressure change. A large diameter, narrow cross section impeller will give you that. If you can find a 2-stage impeller, so much the better.