Baffles are attached to the inside vertical wall of the tank by means of welded brackets four equally spaced baffles are usually sufficient to prevent liquid swirling and vortex formation the optimum baffle width (wbf) depends on the impeller design and fluid viscosity, but is of the order 1/10 to 1/12 the tank dismeter for clean, low-viscosity liquids, baffles are affached perpendicular to wall as illustrated in figure 8.4 (a)