The mixers and Agitators maximize process flexibility by allowing blades to be installed, removed, and changed to various pitches, depending on what works best for the application at hand. From a maintenance perspective, The blades are desirable because individual blades can be replaced if they become damaged, not the entire agitator; hence, the mechanical seal isn’t disturbed and repair costs are minimized.
Homogenizing agitators ; - due to its capacity for intensive dispersing mixing, this type of agitator is perfect for achieving high homogeneity of the product. A homogenizing agitator is able to digest powders, fibrous substances. The turbine may be built in directly in the bottom of a tank or in an additional casing connected with the tank chamber in a closed cycle. There are also in-line systems, where the agitator is an separate device. Such a design permits reduction of investment costs wherever homogenization of the product is not required throughout the process.
Agitator models | Application | Advantages | Disadvantages |
Paddle: · Flat paddles · Finger paddles · Gate paddles | · Solid mixing · Slurry mixing | · Heavy duty mixing · Adjustable to 2 or 4 blades · Excellent for low-speed | · High power consumption · Inefficient liquid circulation |
Counter-rotating paddles | Paste mixing | · Efficient in the laminar condition · Blending | · Vibrates at high speed · Not suitable for liquid mixing |
Tumbling | Blending | Paste and viscous material mixing | Not suitable for fluid solutions |
Disk and cone | Polymers and dispersionpreparation | Viscous solution mixing with 60 revolutions per second | Paste mass cannot be handled |
Free shaft suspension | Sugar processing | Suspension, Thickening operation | High power requirement |
Impeller type | Emulsion preparations | · Good temperature control · Creates axial flow · Good phase mixing | Not for viscous materials |
Turbine agitator · Straight blade · Pitched blade · Vaned disk · Curved blade | Liquid and gas reactions | · Excellent for dispersionoperations · Creates good radial flow | Only for less viscous liquid below 15 to 20 Ns/m2 |
Slotted rotary · Rotating disk | Powders and | Unique particle size and homogeny product formation | · Minimum axial flow · Operates better only for 0.1 to 0.01mm particle size solids |
Screw · Screw in cone | Food and snack processing | Homogenization of high viscous materials | Not suitable for miscibility operations |
Helical · Ribbon type · Helical screw | Polymer and paints processing | Handles viscoelastic liquidsthat are more than 20 Ns/m2 | Less radial flow patterns |
Gate | Blending operations | · Good speed control · Handles pseudoplastic liquids | Not suitable for gas to liquid operations |
Anchor · Round anchor · Combine anchor and gate | Milk and fat processing | Efficient heat exchange between the reactor walls and reaction mass (fluids) | · High power consumption · Requires heavy duty gearbox |
Propeller | · Dairy and food processing · Chemicals processing | · Less Metzner –Ott shear rate constant · Homogenization · Good miscibility | · Motion of liquid starts on one spot · Dead spots formation at high rotation speeds · The occurrence of solids settling at low speeds |
Example
Rotary Airlock Valve Gear Reducer Mixing Tank & Agitator Mixer