1) Ribbon Agitator:
Good when blending materials of like size, shape and density such as powders or granular ingredients.
Lateral scrubbing action of inner ribbon against the outer ribbon produces heat. This can be useful when coating ingredients.
Choppers can be added when incorporating liquids or pastes and to disperse minor ingredients.
Ribbon agitators are most commonly used in the food industry where bulk products are repeatedly blended.
2) Paddle Agitator:
Good when blending materials of dissimilar size, shape and density. Paddles scoop ingredients from the bottom of the trough and lift them into the product stream.
Low shear mixing is useful when blending friable or oversized ingredients.
Choppers are often used in conjunction with paddle agitators to reduce product size, incorporate colorants or other minor ingredients.
Sanitary paddle agitators are the easiest to clean and sanitize.
Paddle agitators are fitted with tighter clearances with the trough than ribbons to allow more efficient clean-out at the end of each batch. Paddle agitators are efficient with batch sizes down to 20% of the rated capacity of the blender.