Sieve Shaker , Principle , Working

Sieve Shaker 

A polydispersed powder is subjected to size separation to obtain the powder of desired size or size distribution .

Sieve shaker is the most commonly used instrument for this purpose in pharmaceutical industry .

Principle :

Sieve shaker is based on the principle of agitation .

- Vibration

- Oscillation

- Gyration

Construction :

The shaker has a platform for the sieve to rest . sieve are placed on the platform in the ascending order of the sequence like coarser sieve (Sieve no 10) at top while fine sieve (Sieve no 120 ) at bottom which is connected to the collector pan .

The Other accessories like capping , screws , frames , timer are provided for the smooth functioning of shaker .

Working :

1. Sample under size saperation is placed on topmost region on set of sieve i.e. on coarse sieve and finally closed with lid .

2. the whole set of sieve is placed on shaker and fixed at appropriate position .

3. Equipment is turned on and allows the material to get moved on sieve due to vibration or agitation .

4. Particles will pass through sieve aperture and moves to next sieve until they get retained on sieve .

5. Particles retained on the sieve are called as oversized particle and those passed through sieve are termed as undersized particles .

6. After Specific time Period (20 min) the shaker is turned off . other particles are retained on each sieve .

Advantages :

1. Cost Effective

2. Simple and no skilled person is required .

Disadvantages :

1. chances of sieve blending .

2. Not Suitable for wet sample .

3. Due to Agitation , Particles colloid each other thus chance of size reduction . this leads to error in estimation .

4. Not able to measure the size above 50 micrometer .