Equipment’s for Cleaning, Grading and Separation

A) Separation based upon size:

1. Screen cleaner:

• The mixture of grain and foreign matter is dropped on a screening surface which is vibrated either manually or mechanically.
• A single screen can make the separation into two fractions.

2. Hand operated screen cleaner:

• The separation take place due to difference in size of grain and foreign matter.
• The cleaner is operated by hanging on an elevated point with the help of four ropes.
• Grain is fed on the screening surface in batches.
• The cleaned grains are retained by the bottom sieve which can be discharged by pulling a spring-loaded shutter.
• Impurities of large size, stubbles, chaffs etc. are retained on the top sieve can be removed easily.
• Downstream from the bottom sieve consists of dust, dirt, broken, shriveled grain etc. drop-down during operation.

3. Air screen cleaner:

• The air screen cleaner uses three cleaning systems; blowing or aspiration, scalping screens and grading lower screens.
• It is of 3 types:

a) Vibratory screen: These screens are tightened together and suspended by hangers in such a manner that these have horizontal oscillating motion and slightly vertical motion.

b) Rotary screen: There motion is circular in horizontal plane. These have either single or double drum.

c) Pedal cum power operated air screen grain cleaner: designed to operate manually either using hand or pedal systems or by electric motor. consists of grain hopper with feeding mechanism, sieve box on hanging shoes, blower unit, driving and eccentric unit.