The working principle of the grain sorting machine is mainly based on the differences in physical properties between grain and impurities. It achieves efficient separation through multiple technologies such as screening, winnowing, photoelectric sorting, and gravity separation, which are detailed as follows:
1. Screening Principle
Screen Mesh Structure: grain sorting machine are usually equipped with multi-layer screen meshes, and the mesh specifications can be customized according to different grain types and impurity sizes. For example, the upper layer of the screen mesh for corn may be 10 mm and the lower layer 5 mm; while the upper layer for soybeans is 5 mm and the lower layer 2 mm.
Screening Process: After entering the screening mechanism, the grain moves on the screen mesh through vibration or rotation. Impurities larger than the screen holes are retained on the mesh, while grain particles smaller than the holes fall through, achieving preliminary screening.
2. Winnowing Principle
Winnowing Device: The grain sorting machine is equipped with a winnowing device, which uses the force of airflow to separate light impurities from heavy grain.
Winnowing Process: When the grain passes through the winnowing device, light impurities such as dust and rice husks are blown away by the airflow, while the heavy grain continues to fall, achieving a more refined separation effect.
3. Photoelectric Sorting Principle
Photoelectric Sensors: Some grain sorting machine are equipped with photoelectric sensors that can detect the optical properties of grain, such as color and luster.
Sorting Process: As the grain passes through the photoelectric sorting area, the sensors capture the color information of the grain and transmit the data to the control system. The control system compares and analyzes the data according to preset parameters, and then drives the actuator (such as a pneumatic or electric push rod) to distribute grain particles of different colors into different collection containers, realizing photoelectric sorting.
4. Gravity Separation Principle
Specific Gravity Difference: There may be differences in specific gravity between grain and impurities, and gravity separation technology uses this difference for separation.
Sorting Process: In the gravity separator, grain and impurities are evenly fed onto an inclined, reciprocating vibrating porous plate. A controlled airflow fluidizes the mixture into a semi-suspended state, which then flows downward and is discharged from the lower end. Heavier impurities (such as stones and clods) move upward along the surface of the porous plate due to the reciprocating vibration, and are discharged through the stone collection area, completing gravity separation.