Pressure Ratio in Multistage Centrifugal Blower

This is a MathCad document that shows the predicted pressure ratio per stage in a centrifugal blower. The impeller which is modeled here is typical of what you would find in a Shop-Vac or Lamb blower. This calculation was done during development of a more efficient blower. The project resulted in a 70% more efficient blower with a modest increase in manufacturing cost. The original blade configuration is shown below. The blower is patented 6,543,449

Calculation of efficiency and pressure ratio for 3 stage centrifugal blower - Steve Harrington 1-7-97

This model was used to investigate the effect of changing the blade angle on the pressure rise per stage. A custom dynamometer and flow bench was set up to measure the torque, RPM, flow and pressure for a single stage of the blower. This was used to determine the efficiency used in the calculations above.