Rectangular Airlift Pumps Cylindrical Airlifts (Wurts et. al., 1994) Think inside the box. Cylinder vs. Square Tube • Volume, 3 (diam) x 10 Cylinder = 71 • Volume, 3 x 3 x 10 square tube = 90 • Square tube = 27 % more volume • Both use same horizontal space Surface Area/Volume Ratio Riser Dimensions Area/Volume (in2/in3) Cylinder 3 x 12 1.33 Square Tube 3 x 3 x 12 1.33 Rectangular 12 x 12 x 30 0.23 Multi-cylinder vs. Rectangular Riser Unit Dims. Surface Area 40 cylinders 3 x 12 (cyl.) 4522 One rectangular 12 x 12 x 30 1008