Object:
To separate the fibres from seed
The constructional detail of the machine is clearly shown in fig. The seed cotton is placed in bulk on the table. By means of the reciprocating motion of the table by the crank arrangement, the seed cotton comes into contact with knife roller (formed of a number of knife discs).
Auxiliary roller breaks the large cluster of seed cotton and maintains a constant supply of cotton to knife roller.
Knife portion being arranged in such a manner that anything coming into contact with it is given a reciprocal or to and fro motion as well as being subject to a striking action due to its revolution.
The seed cotton is carried forward in the direction of knife roller's motion until it is brought into touch with leather roller. This roller, which has a much roughened surface, due spirally-formed saw cuts. Has pressing against, it by means of spring and steel doctor Knife.
The cotton fibres brought into contact with the leather adhere to it, and are carried round past .the knife. It is impossible for the seeds to follow. So, seeds will remain at the point of contact of the doctor knife and leather roller, with the fibres still connected with it. The essential feature of this gin now comes into play.
The knife roller is so set as to act upon, these adhering seeds, and it gives to them a gentle to and fro motion, repeated very quickly 'and at the same time a slight striking action or pressure also repeated quickly. The combined action soon causes the seeds to separate from the fibres and to fall down through the grid to floor. The freed fibro passing forward is stripped from the roller by some arrangement of the stripping board.
The seed cotton not taken up by one leather roller (on the right of the figure) is brought round into contact with another 1eather roller where same process as described above is gone through and to which the same parts equally apply.
SETTING
1. Seeds cannot get between dish rail and knife roller. Carelessness here produces large quantities of crushed seeds
2. Sharp edge of the doctor knife does not cut the fibres.
3. The degree of pressure of the doctor knife upon the leather roller can be varied by means of spring and thumb screw according to the tenacity with which the fibres adhere to the seeds.
4. The leather roller should be parallel to the knife roller and the setting between leather roller and knife roller, should be 1/3 of the diameter of the largest seed.
If this setting is too near - the seeds would be broken. If this setting is too wider large seeds would not be acted upon by knives and m/c would block itself by an accumulation of un stripped seeds.
Knife roller gin is suitable to process coarser and medium Types of Indian cotton. The Indian Cotton fibres are not too easily separated ' from seeds, so heavier beating on seed is required to. Separate the fibres. This is achieved in this gin by giving heavier beating of the rapidly revolving knives of the roller on the seed cotton.
