Propellers
Principle
Shearing force is the main principle behind the propeller mixer.Construction
The vessel has a propeller attached to it. Angular blades enable fluid to flow in both axial and radial directions through a propeller. Propellers are small and can increase up to 0.5 meters in size depending on the size of the tank. 8000 rpm is the maximum speed for a small propeller.Working
- When a centrifugal force is exerted by the propeller blades on the liquid, it backs up on the vessel's sides causing a depression around the shaft.
- Increasing the rotation speed may cause air to be sucked into the fluid, causing possible frothing and oxidation.
- Incorporate vertical baffles into the vessel as another method of suppressing vortex.
- Vortex reduction can be achieved by installing vertical propellers.
- Three propeller blades (4 feet in length) are used in vertical propeller mixers.
- A horizontal propeller or an inclined propeller or a marine propeller can also be used on a side entry mixer. Their impeller shaft is inclined so their impeller shaft is at an angle with the vessel axis to improve the process. These propellers provide good blending ability on small batches of low to medium viscosity.
Uses
- Liquids and dispersions need to be mixed up with propellers when large quantities are involved.
- Liquids with a viscosity of 2 Pa.s. can be mixed with these mixers.
- A glass lining makes these capable of handling corrosive materials.
Merits
- Whenever high mixing capacity is needed, propellers are used.
- Their maximum viscosity can be 2 Pa.s or less, making them very effective for mixing liquids. solids with a fine particle size up to 10%.
- Lab-scale mixing of gas-liquid dispersions is possible with them.
- Materials become more homogeneous when propellers are used,
- The same pattern can be used for both drying and pressing
Demerits
- Foaming and oxidation are caused by a vortex.
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