The Structural Design of the Banana Screen

Introduction

In recent years, with the development of coal processing technology, vibrating screens, due to their high efficiency, high reliability and strong batch processing capacity, have been applied in the coal processing process for operations such as classification, dehydration and dewatering. As a type of vibrating screen, the application of Banana screen not only reduces the purchase cost and subsequent management expenses, but also saves the floor area of the factory. Moreover, Banana screen, with its high efficiency, large processing capacity and high reliability, is widely used in the coal processing industry.

The structure of the Banana screen

The Banana screen is an efficient linear vibrating screen, used for removing mud from raw coal, removing media from clean coal, and removing media from gangue in coal mines. The Banana screen has been optimized through the application of equal-thickness screening principles and linear vibration theory. The vibration parameters such as amplitude, frequency, and excitation force are set appropriately and reasonably.

The side walls, main beam, cross beam, and various structural components have high rigidity, strength, and long service life. A pair of box-type exciters are installed on the main beam of the exciters, and they are connected to the driving mechanism through polyurethane coupling and spline transmission shafts, reliably and smoothly transmitting power and linear vibration force. The screen body vibrates the materials at the predetermined frequency, causing the materials to be lifted and separated layer by layer and advance forward. From the input end to the discharge end, the screening process is carried out through the screen surface.

The screen body is mainly composed of side walls, cross beams, excitation beams, lifting beams, and rear back plates. Each component is made of high-quality structural steel through precise manufacturing. The cross beams, excitation beams, and lifting beams are all heat-treated after welding, and the screen body is machined using high-precision CNC machines. Then, high-quality imported steel hooks are selected, and the screen body is riveted firmly using advanced assembly techniques.

The side plates have no weld seams, and the cross beams and excitation beams have large cross-sectional coefficients and high rigidity. The surface of the cross beams is coated with polyurethane wear-resistant material, and the surface of the screen body is treated to Sa2.5 level and then sprayed with polyurethane protective paint. Each process of the screen body production is subject to strict inspection and control. The screen body structure has been optimized for design, making it lightweight. The screen body can withstand high-load and high-frequency vibration work conditions, avoiding cracking and wear of components, and has higher fatigue resistance, reliability, and service life.

The sieve layer of Banana Screen

Single layer

The sieve surface of the single-layer Banana screen is arranged with five or six sections of different inclinations. According to the principle of equal thickness screening, the thickness of the material layer remains basically unchanged from the inlet to the outlet. The ratio of material volume to flow velocity on each section of the sieve surface is stable, the material layer is high, and it presents a uniform state. The screening efficiency is significantly improved, which is 1-2 times higher than that of the vibrating screen with the same effective area. It is suitable for the size classification of large and medium-sized particles with high fine content, and can also be used for dehydration, desilting and dewatering operations.

Double-layer

Double-layer structure, in the banana screen, the upper layer is an elliptical sieve mesh, and the lower layer is a linear sieve mesh with an angle. This structure enables the materials to have different trajectories during the screening process, thereby achieving more precise and efficient screening. The upper sieve plate has a large inclination angle, while the lower layer is basically arranged horizontally. The feed passes through the upper sieve plate at high speed, allowing the powder to be preliminarily separated. The materials move at high speed on the sieve plate, separating into thin layers, which can efficiently handle a large amount of feed.

Technical features of Banana screen

(1) The feeding end of Banana screen has a large inclination angle, and the material has a strong throwing force and high movement speed, which enables the material to be quickly stratified. The middle part gives the already stratified material the same acceleration as a conventional screening machine, allowing fine particles to have sufficient opportunities to pass through the screen. The unit screen surface screening capacity is improved, and the thickness of the material layer on the screen from the feeding end to the discharging end remains basically unchanged.

(2) The screen plate of Banana screen is made of polyurethane and stainless steel mesh bars. The four sides of the screen plate are made of polyurethane material, which has good wear resistance and low noise characteristics. The middle part is made of stainless steel mesh bars, which have higher strength, greater wear resistance and higher opening rate compared to other materials.

(3) The installation structure of the screen plate is simple. There are no bolts connecting the screen plates to each other. They are tightly combined by the plasticity of the polyurethane material. The screen plates are not likely to loosen, reducing the occurrence of accidents. The screen plate rail seat of Banana screen and the supporting beam have protective cover strips, so the bolts under the rail seat will not be corroded or worn by coal and water.

(4) The exciter of Banana screen adopts an integral box-type exciter, which is installed on the upper beam of the screen box. The box body contains an active shaft and a driven shaft, and each shaft has a pair of equal-weight eccentric blocks. Through the synchronous reverse rotation of two shafts by gears, the eccentric blocks rotate, generating centrifugal force to form the excitation force.

(5) The protective cover strips on both sides of the screen surface of Banana screen have a simple and robust fastening structure. The two contact surfaces of the protective cover strips on both sides are inclined planes, with a large contact area. The upper part is a pressure plate, which is not likely to loosen.

Conclusion

The overall structure design of the Banana screen is compact, with a small footprint, making it easy to be arranged and installed in limited spaces. At the same time, the maintenance of the Banana screen is relatively simple, with easy replacement of components, which reduces the maintenance costs and time costs in the long run.