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Renin Angiotensin Mechanism.

Mixing: Sigma Blade Mixer.

 

Principle:

  • It's an “Agitator  Mixer”.

  • It works on the mechanism of Shear and Convective Mixing.

  • This type of mixer employs a stationary container to hold the material and brings about mixing by means of moving  screws, paddles or blades.

  • They cause folding, kneading, tearing and mixing of the materials.


Construction:

  •  Consists of a vessel in which it uses two mixer blades, the shape of which resembles the Greek letter “sigma” (Σ).

  • The loading of material is done from top by opening the lid.

  • The unloading is done by tilting the entire vessel.

Working:

  • The materials to be mixed are introduced to the mixer through the lid.

  • The two blades rotate towards each other and operate in a mixing vessel which has a double trough shape, each blade fitting into a trough.

  • The two blades rotate at different speeds, one usually about twice the speed of the other, resulting in a lateral pulling of the material and divisions into two troughs, while the blade shape and difference in speed causes end-to-end movement.

  • After mixing the material is removed by opening the lid.

  • Material with similar size and density mixes faster than the materials with density difference and particle size change.

Uses:

  1. For granulation during tablet manufacturing.

  2. Semi-Solid mixing.

  3. Commonly used in bakery.

Advantages:

  1. Minimum dead space during mixing.

  2. Suitable for solid-solid and semisolid mixing

Disadvantages:

  1. Fixed speed.

  2. Batch type only: No continuous operation.


Commonly Asked Questions:

  1. Define Mixing. With help of a diagram describe the principle, construction and working of the Sigma Blade Mixer.

  2. Write a short note on Sigma Blade Mixer.
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