Most of the people who want to start ginning factories do not have adequate knowledge about the ginning principles of various ginning technologies available in the world and they go primarily by the available machinery in their area without considering the correct requirement for the type of cotton available to them for ginning. This is many time resulting in avoidable loss of fibre and damage to fibres, finally resulting in lower realization of value.
The primary criteria which should be considered before selecting any ginning technology may be summarized as below:
If the length of the fibre is above 28 mm it will not be beneficial to select Saw Gin as some damage in the fibre length is certainly going to take place, hence Double Roller or McCarthy Single Roller Gins should be necessarily used to obtain optimum results if fuzzy seed cotton is to be ginned. Double Roller Gin being cost effective the same are preferred over McCarthy Single Roller Gins. However for black seed cotton Double Roller or McCarthy Single Roller will give equally good results but Rotobar can also be used.
If the trash contents in the seed cotton are on the higher side either the additional cleaning equipments should be used or only Saw Ginning should be used as in other technologies the same will choke the seed clearance grid in McCarthy Single Roller Gin or Double Roller Gin while the Saw Gin will crush the leafy material and mix it with the lint which can be separated in saw type cleaner or similar devices. Hence for the high trash machine picked seed cotton either additional cleaning equipments should be used before ginning or Saw Gins should be selected.
If the moisture contents in the seed cotton are over 8% the Saw Gin should not be used to avoid any damage to the fibre. The Roller Gins can take up to 10-11%
moisture but above that the drying process should be adopted before feeding the seed cotton to the ginning machines and the moisture contents should be brought down to below 10% before ginning.
If the seed cotton is machine picked it is bound to have higher initial trash contents which should either be removed before feeding to gins or the saw gins in case of short and medium staple cotton or rotobar for long and extralong cotton should be used which have in built cleaner feeder however the best thing would be to remove the higher trash at the seed cotton stage only and then use the Double Roller or McCarthy Single Roller if used would give better fibre parameters. or the hand picked cotton where the trash contents are lower the Double Roller or McCarthy Single Roller Gin will give best fibre parameters i.e. lowest neps and highest fibre length but there are exceptions like in Pakistan though the cotton is hand picked but due to harvesting practices it is having very high trash, hence Saw Gin is widely used.
It is seen that Double Roller Ginning Technology is most power effective i.e. for per unit of production lowest power consumption is required in case of Double Roller therefore the consideration for power cost per unit is also very important.
Posted in: Textile Ginning