Why are sunflower seeds shelled in the sunflower oil factory equipments?

Sunflower seed and sunflower oil presser

Sunflower oil is a new kind of cooking oil now. It’s recommended as one of the healthy oils by the WTO. The process of sunflower oil making machine includes three main sections. They are sunflower oil pretreatment and pressing, sunflower oil extraction machine and sunflower oil refinery section. The pretreatment part is very important in the whole process. It will influence the quality and oil yield rate of the sunflower oil. While the sunflower seeds shelled machine is necessary in the sunflower oil pretreatment. The shell of sunflower is about 20% of the sunflower seeds. Through there is little oil in the shell of oil sunflower seed, the harmful of the shell is more than the profit of oil in the shell.

The reasons why are the sunflower seeds shelled as follows:
The shell of sunflower will harmful to the oil presser. The life of screw of oil presser will be reduced by the shell.
There are much wax in the sunflower seed. When the shell is not moved, the wax will keep in the oil. The quality of final oil will not good as the oil from sunflower without shell.
The consumption of the refinery is increased, because the quality of final oil is bad.