Project Overview

The designed capacity of this project is to process 13,333 t of raw coal per day, with a raw coal processing capacity of 833 t/h. The plant operates 330 days per year, 16 hours per day, with an annual operating time of 5,280 hours.

Coal preparation process: Lump coal of 300–50mm (adjustable) and 50–25mm (adjustable) is processed by intelligent dry separation, while -25mm fine coal is reserved for air separation.

The Banana Screen complies with the latest national standards, industry standards, and the requirements of JB/T 5496, and is manufactured according to approved drawings and technical documents in accordance with specified procedures.

Banana Screen Technical Parameters

Equipment: Double Deck Banana Screen

Capacity: ≥420t/h

Material source: Raw coal transferred from the raw coal bunker

Material characteristics: The apparent relative density of the coal seam ranges from 1.23 to 1.55 g/cm³, with an arithmetic average value of 1.41 g/cm³. The moisture content of the coal seam (Mad) ranges from 4.69% to 16.21%, with an average moisture content of 10.27%. The predicted maximum total moisture content (Mt) is approximately 30.94%.

Feed particle size: 0–300mm

Double amplitude: 8–10mm

Vibration isolation system: Steel helical compression springs

Screen Panels

Effective screening area: 2×3.6m width × 7.3m length (double deck)

Screen opening size: Upper deck 2mm; lower deck 0.5mm

Screen deck inclination angle: 10°, 14°, 18°, 22°, 26°, 30°

Screen panel type: Polyurethane frame rail-mounted screen panels

Working Principle and Main Components

The Banana Screen consists of multiple sections of screen decks. From the feed end to the discharge end, the inclination angle of the screen surface gradually decreases. During operation, the feed end has a larger inclination angle, allowing materials entering the screen surface to move forward rapidly with higher acceleration and achieve quick stratification. A large amount of material smaller than the screen openings fully contacts the screen surface and passes through efficiently. At the discharge end, the inclination angle becomes gentler, slowing down material movement and providing sufficient residence time for the remaining fine particles to pass through the screen, greatly improving screening efficiency.

Equipment Performance Features

Side Plates and External Protection Plates

The screen machine side plates and external protection plates are made of Q355D high-quality low-alloy high-strength structural steel plates. The steel plates comply with the special technical requirements of GB/T3274 standard. This material features high strength, fatigue resistance, impact resistance, corrosion resistance, low-temperature resistance, wear resistance, and good machinability. It provides excellent overall mechanical properties and is highly suitable for Banana Screen manufacturing.

The side plates and external protection plates are designed using CAD computer-aided design. Data is transmitted from the computer control center to a high-precision laser cutting machine to complete cutting and hole processing in one operation.

The side plates are cut from a single steel plate without splicing. The manufacturing accuracy is ≤±0.03mm, exceeding the AS3678-250 standard, ensuring high equipment manufacturing precision.

Crossbeam

The screen machine crossbeam adopts a rectangular hollow structure with high rigidity and lightweight characteristics, completely eliminating vertical splicing. This structural design provides a high safety factor and is suitable for Banana Screen operating conditions.

The rectangular crossbeam is fully welded through with the connecting flanges at both ends. After welding, overall heat treatment is performed to eliminate welding stress. The flange connection surfaces are precision machined to ensure end-face perpendicularity.

The corner supports connecting the longitudinal screen panel support rails and crossbeams are fully sealed welded to prevent liquid from entering and corroding the crossbeam.

Exciter Base Beam

The exciter base beam plays a critical role in the operation of the Banana Screen. It adopts a box-section design with internal reinforcing plates, providing high rigidity and lightweight characteristics.

The reinforced flange of the large exciter adopts a special design to effectively improve the strength of the Banana Screen. All welds undergo complete stress relief treatment. The exciter mounting surface adopts a special structural design and is machined according to strict accuracy requirements, effectively improving the overall strength of the Banana Screen.

Rail Beam

The rail beam adopts high-strength hot-rolled unequal angle steel and is fixed above the crossbeam by rivets to support the screen panels. This rail beam structure features simple design, high strength, and long service life.

Rear Back Plate

The rear back plate of the screen machine is made of Q245R steel plate through bending. The rail beam and rear back plate are connected by rivets. Reinforced bent channel steel is installed at the connection area to effectively improve the strength of the rear back plate and completely prevent cracking.

Screen Frame

The screen frame is manufactured using high-quality low-alloy high-strength structural steel plates and profiles. It features advanced design, reasonable structural arrangement, high rigidity, high strength, durability, and reliable operation.

Replaceable parts of the screen frame are assembled using high-strength bolts and self-locking nuts. The crossbeams and exciter base are connected by rivets.

The flatness error of the formed screen panel support frame is not more than 1mm per square meter, and the difference between the two diagonal lengths is not more than 1mm per meter.

The screen frame adopts a riveted structure, ensuring that the side plates are free from welding stress and fundamentally solving the problem of bolt loosening from the structural design perspective.

The steel structure of the screen body is shot blasted to achieve Sa2.5 surface cleanliness, followed by multiple layers of protective and wear-resistant primer coating.

The tensile strength of rivets used for connecting main components is not less than 785MPa. The performance grade of high-strength bolts is not lower than Grade 10.9S specified in GB/T1231.

Vibration Isolation System

The screen machine adopts steel cylindrical helical compression springs for vibration damping. The spring material is 60Si2Mn. EXCT vibration isolation springs adopt special parameter design, featuring high load capacity, long service life, and excellent vibration damping performance.

Screen Panels

The screen panels are fixed using polyurethane slot structures, making installation and removal convenient and fast. Replacement of all screen panels on the entire screen machine can be completed by only two workers within 30 minutes.

The feed section is equipped with a blind plate impact protection area, and the screen surface is reinforced. Rubber plates are installed between the screen panels and support beams to provide cushioning. Material particle size is considered in the design to prevent blockage.

Both sides of the screen panels adopt polyurethane side strips and polyurethane wedge blocks for compression installation. This not only fixes the screen panels but also effectively prevents material abrasion on the screen frame side plates, extending the service life of the screen frame. No coal leakage occurs at the connection between the screen frame and screen panels.

Drive System

The drive system consists of a motor, small pulley, V-belt, large pulley, and end bearing housing, which drive the exciter rotation and generate linear motion of the Banana Screen.

The two exciters are connected through a universal drive shaft to achieve synchronous operation. This drive method provides high torque transmission capacity, excellent transmission efficiency, long service life, and enables long-term continuous and reliable operation.