The gravity separator (gravity selector) focuses on separating impurities in beans based on density differences; the air-screen gravity separator combines air separation, sieving, and gravity separation, resulting in a more complete process and more comprehensive impurity removal.
I. Gravity Separator (Gravity Selector) for Bean Cleaning
Core Principle: Utilizing the difference in specific gravity (density) between the material and impurities, combined with upward airflow and reciprocating vibration, the material is suspended, stratified, and moves along different trajectories, achieving precise separation.
Applicable Impurities: Empty grains, insect-damaged grains, moldy grains, hollow shells, and other impurities with densities different from beans.
Core Function: Refining and purifying, removing impurities of the same particle size but different specific gravities that are difficult to separate by air separation and sieving.
Workflow:
Uniform Feeding: Raw grains (with impurities, including beans) are evenly fed into the gravity separator via an elevator and feeder, forming a thin and uniform layer.
Airflow Suspension: The bottom fan generates upward airflow, lifting the material into a semi-suspended state, amplifying the specific gravity difference.
Vibration-based stratification: The gravity table vibrates reciprocatingly, causing the material to automatically stratify under the combined action of vibration and airflow: Heavier materials (such as pebbles and plump beans) sink to the bottom, adhering closely to the screen surface.
Lighter materials (such as chaff and insect-damaged particles) float to the top.
Differential separation (core process): The screen surface has an angle and special texture, which, combined with vibration and airflow, creates reverse motion: The heavier materials at the bottom (plump beans) move upwards along the screen surface and are discharged from the clean material outlet.
Lighter impurities at the top (chaff and moldy particles) flow downwards along the screen surface and are discharged from the light impurity outlet.
Extra-heavy impurities (such as pebbles) are discharged from the side heavy impurity outlet.
Discharge collection: Clean beans, light impurities, and heavy impurities flow out from their respective outlets, completing the material selection process.
II. Air-Screen Gravity Separator for Bean Cleaning
Core Principle: A three-stage combined process of air separation (removing light impurities) + sieving (removing impurities of different sizes) + gravity separation (removing impurities of varying density within the same particle), removing multiple impurities in one pass.
Applicable Impurities: Dust, straw, broken leaves, large impurities, small impurities, chaff, insect-damaged grains, moldy grains, stones, etc.
Core Advantages: Complete process, high purity, suitable for integrated initial cleaning and fine selection of beans.
Work Flow:
Pre-Air Separation (Removing Light Impurities):Material enters the air separation zone, where the fan generates vertical/horizontal airflow: Beans, being denser, fall vertically.
Light impurities such as dust, straw, and broken leaves are drawn away by the airflow and collected and discharged by the dust removal system.
Vibrating Screening (Removing Impurities of Different Sizes):After air separation, material enters a multi-layer vibrating screen:
Upper Coarse Screen: Intercepts large impurities (such as bean pods, clods of earth, and hemp rope), which are discharged from the large impurity outlet.
Middle layer sieve: Beans pass through the sieve holes, while small impurities (broken beans, mud particles) fall through and are discharged through the small impurity outlet.
Gravity separation (fine selection and purification): After sieving, the material enters the gravity separator, following the same process as the gravity mill: Airflow suspension → Vibration stratification → Differential separation.
Light impurities such as chaff, insect-damaged beans, and moldy beans are separated from heavy impurities such as stones.
Clean material discharge: The cleaned beans, after three stages of cleaning, are discharged from the final outlet and can be directly packaged or proceed to the next process.
III. Core Comparison (Gravity Separator vs. Air Screen Gravity Separator)
Gravity Separator
Principle: Single gravity separation.
Process: Feeding → Airflow suspension → Vibration stratification → Differential separation → Discharge.
Advantages: High selection accuracy, suitable for separating impurities of the same particle size but different specific gravities.
Limitations: No pre-processing air separation or screening; requires primary cleaning equipment.
Applications: Fine processing of beans, seed selection.
Air Screen Gravity Separator
Principle: Combination of air separation + screening + gravity separation.
Process: Feeding → Pre-air separation → Vibrating screening → Gravity separation → Discharge.
Advantages: One-stop impurity removal, high purity, high efficiency.
Limitations: Complex structure, higher cost.
Applications: Integrated primary cleaning and fine processing of beans, large-scale processing.
Suitable for legumes and grains: mung beans, soybeans, black beans, kidney beans, broad beans, chickpeas, sesame seeds, rapeseed, wheat, rice, etc.
Post time: Mar-19-2026
