the number of baffles is usually 4; the number of number of impeller blades ranges from 4 to 16 but is generally 6 or 8. Special situations may,of course,dictate different proportion from those above;it may be advantageous,for example,to place the agitator higher or lower in the tank,or a much deeper tank may be needed to achieve the desired process result.The listed"standard"proportion.nonetheless,are widely accepted and are the basis of many published correlations of agitator performance.