White Rice Grading Screen: Functional Positioning and Working Principle

The white rice grading screen is a key equipment for fine processing of finished rice products in the rice processing process. Its core function is to accurately grade the polished and sorted finished rice into four standard grades: whole rice, general rice, large broken rice, and small broken rice based on differences in grain size. It can also be widely adapted for the separation of other granular materials, providing basic support for subsequent product packaging, quality control, and market segmentation.

1、 Core working principle

The grading logic of white rice grading screen is based on the essential differences between whole rice and broken rice particle types (length, diameter), and achieves precise separation through the synergistic effect of "plane rotation motion+multi-layer screen screening". The specific process is as follows:

Motion driven and material diffusion: After the equipment is started, the screen body rotates in a flat plane under the drive of the transmission mechanism (non violent vibration to avoid material breakage). The mixed white rice to be graded enters the upper screening surface through the feeding port. Under the dual action of rotational force and frictional force on the screening surface, the material spreads evenly and smoothly along the screening surface, avoiding local accumulation that affects the grading efficiency. Particle size difference screening: The sieve body is equipped with multiple layers (commonly three or four layers) of specialized sieves with different pore sizes, and each layer of sieve corresponds to a level of material separation:

Upper layer sieve: with a large aperture Z, only broken rice (large broken rice, small broken rice) and ordinary rice are allowed to pass through, intercepting the entire meter of length Z on the sieve surface and pushing it to the discharge port of the entire meter with rotational motion; Middle layer sieve: The aperture is second, intercepting ordinary meters and allowing smaller large and small broken meters to pass through; Lower/Bottom Screen: Further separate large and small broken rice according to the difference in pore size, and finally complete the classification through their corresponding discharge ports. Multi level extraction optimization effect: For equipment with three or four layer specifications, the screen layout and process design adopt a "connected two to three extraction" logic - that is, through the progressive screening of multi-layer screens, core grade materials such as whole meters and general meters are intercepted and purified multiple times, greatly reducing the mixing of materials of different grades and significantly improving the classification accuracy and product purity.

2、 Special note

It should be noted that different specifications and models of white rice grading screens (such as processing capacity, number of layers, and screen aperture) may have differences in screen configuration, rotation speed, and feed rate adaptation range. The actual grading effect needs to be adjusted comprehensively based on specific equipment parameters and the characteristics of the material to be processed (such as rice variety and particle uniformity).