Fruits can be sorted by size or weight. For spherical fruits with regular shapes, such as widely cultivated plums, plums, olives, garlic, oranges, tomatoes, etc., grading by size is a simple and easy method.

Grading by size, or diameter, usually takes advantage of the ever-changing pores through which the fruit falls or rolls out when the pores exceed the diameter. Because the drum classifier works smoothly, and will not cause mechanical damage to the fruit, classification efficiency is high, low noise, so in line with the development trend of modern agricultural machinery.

In many places, either the fruits produced in a certain area are classified in concentrated places, or the food processing enterprises grade specific varieties of fruits in a short period of time during the fruit ripening season, with a small amount of grading and a short time for the machine to use each year. Therefore, the FstSort structure is simple, easy to manufacture, low cost, easy to adjust the use of the grader is more popular.