Positioning a Mixer in a Cylindrical Vessel

Figure 1: Aiming the shaft off center avoids vortexing and allows strong top-to-bottom turnover. This is the best position for most mixing and blending.

Figure 2: A center stirrer with a straight-blade propeller creates vortexing in an unbaffled vessel. Vortexing speeds up dispersion and dissolution of light liquids and hard-to-wet powders.

Figure 3: Baffles prevent vortexing and excessive aeration created by center-mounted stirrers with straight blade propellers. Four vertical baffles should be equidistant around the circumference of the vessel. Baffle width should be 1/12 the diameter of the tank.

Figure 4: You may want more than one kind of stirring action for multiple-step mixing. For example, if you first need to dissolve light powders, you can center the stirrer to create a vortex. Then you can reposition the stirrer at an angle to maintain a uniform suspension or to blend in other fluids. Portable clamp-mount stirrers make repositioning easy.