Roller graders revisited

Roller graders or sizers, delicate products

Sizers or graders using moving and turning rollers for very delicate products

The graders (sizers), shown here, are very versatile, classifying almost all products (fruits, vegetables, tubers, nuts, strawberries, etc.). It is so delicate with the product that it also sorts mature tomatoes without breaking them.

The turning rollers carry the product from one side of the grader to the other and during this movement the distance between the rollers increases continuously. The results is that the smaller products falls between the rollers in the beginning and the biggest product comes out at the end.

Perpendicular under the rollers small conveyor belts are placed that receive the different sizes.

The number of sizes these kind of graders can grade depends on the number of the small conveyor belts.

These graders have two minor drawbacks:

1. Changing the rollers (you need different rollers for different shaped products)
2. Adjusting the sizes to grade.

These two tasks are a bit uncomfortable.

The rollers of a roller sizer

A roller sizer (grader) with 4 exits for 4 product sizes.

Depending on the shape of the product to be sorted, suitable rollers are chosen.

grading peaches

grading apples

Specially shaped rollers

Rollers covered in rubber, for softer treatment of delicate products

To get a better understanding how these graders work, watch the movies.