A single-layer banana screen, also known as a multi-slope screen, is a type of vibrating screen that is widely used in mining, aggregate, and mineral processing industries. It is named for its banana-like shape, with multiple deck slopes that increase progressively from feed end to discharge end. This design helps to achieve higher throughput and more efficient separation. 

Working Principle of Single Layer Banana Screen

Feeding

Material Introduction: The material is fed onto the screen at the feed end. The feed rate and material distribution are critical for efficient screening.

Initial Screening: The initial section of the screen deck is typically inclined at a steeper angle, which helps to rapidly stratify the material and initiate the screening process.

Vibration

Vibratory Motion: The screen deck is vibrated using an eccentric drive mechanism. The vibration helps to move the material along the screen surface and separate particles based on size.

Amplitude and Frequency: The amplitude and frequency of vibration are crucial parameters that influence the screening efficiency. They can be adjusted based on the material characteristics and desired separation size.

Screening Process

Multi-Slope Design: The banana screen features a series of decks with progressively decreasing angles. The top deck has the steepest angle, and the angle decreases towards the discharge end. This design helps to maintain a higher material velocity at the feed end and slower velocity at the discharge end.

Material Stratification: As the material moves along the screen, it stratifies, with finer particles moving towards the bottom and coarser particles remaining on the top. This stratification enhances the separation efficiency.

Separation: The material is separated into different size fractions as it moves across the screen. The undersized particles pass through the screen apertures, while the oversized particles are discharged at the end.

Discharge

Oversized Material: The oversized material that does not pass through the screen apertures is discharged at the end of the screen.

Undersized Material: The undersized material that passes through the screen is collected and can be further processed or sent to the next stage of the production process.

Key Features and Advantages

High Capacity: The banana screen's design allows for higher throughput compared to traditional flat screens.

Efficient Stratification: The multi-slope design enhances material stratification, leading to more efficient separation.

Versatility: It can handle a wide range of materials, including wet, dry, fine, and coarse particles.

Reduced Blinding: The vibratory motion and screen design help to reduce screen blinding and maintain consistent performance.

Applications

Mining and Mineral Processing: For separating ores and minerals based on size.

Aggregate Industry: For classifying crushed stone, sand, and gravel.

Coal Processing: For separating coal into different size fractions.

In summary, the single-layer banana screen operates by feeding material onto a vibrating screen deck with progressively decreasing angles, facilitating efficient separation of particles based on size through stratification and vibration.