Object :
To open and clean the cotton.
Type : Major cleaning point & Loose feeding Bladed beater type (Suspended type of feeding by air suction)
Constructional details of the machine is clearly shown in fig.
It consists the inlet pipe into which the tufts are blown by the material transport Fan.
The rapid revolution of the vertical beater shaft, heavier beating of the striker in cotton against grid bar, centrifugal force and gravity combines effectively to open the cotton and remove the heavier major trash particles from it.
Due to opening of cotton tufts, heavy dust, dirt, sand particles, seed bits & other Vegetable particles, short fibres and other foreign impurities are extracted and passed through the spacing of the grid bars, surrounding the beater.
The cotton, tends to rise to the top of the machine, by the following reasons :
Spiral arrangement of the strikers,
Increase in diameter toward the top and so passage of cotton which rotates with increasing surface speed,
The air current at the top of the machine, after opening and cleaning, the cotton is sucked by the subsequent condenser and discharged into the mouth of the pneumatic pipe line (out let) which is connected and feed the materials to the next machine.
Vertical opener is used to process only low grade and short staple cottons.
Due to high degree of opening action and major cleaning point vertical opener is not recommended for processing long stapled fine cottons. In this case, vertical opener is by passed by suitable by-pass arrangement.
The factors affecting the efficiency of this machine are,
i) The beater speed (400 to 900 RPM): Opening action is increased by increasing the speed of the beater.
ii) Setting between beater blade & grid.
Too close setting will tend to curl the cotton and pass too
much good lint through grid bars. If this setting is wider, the
action on the cotton will be less which affect the opening
action. The beater can be raised or lowered to alter the
setting between the striker tips and the grid bars surrounding the beater.
Strength of air current : If too strong - Cotton will raise and pass through too and affect the opening and trash extraction.
If too weak - Cotton will move slowly and will be over treated. This may give good opening but there is a danger of fibre damage and production of curly cotton.
iv) Angle of grid bar : It should be such that the maximum trash
extraction is obtained with minimum lint loss.
If the angle is too wide - There will be loss of good fibre.
If it is too narrow _ cleaning efficiency is affected.
Hence adjustable grid bars have been introduced in latest models, By means of proper adjustment, the optimum angle can be obtained by trial to suit the particular grade of cotton being processed.
v) Space between the grid bars, angle of grid , setting between
beater and grid bar determine the cleaning efficiency of the
machine. A
