How Does a Roller Screen Work
I. Definition
A Roller Screen is a high-efficiency screening device whose screening area is composed of main bearings with rollers rotating in the same direction, enabling the separation and transportation of materials. Also known as a swing feeder or disc screen, the Roller Screen is suitable for various materials, including wet and sticky ones. Compared with traditional vibrating screens, it is less prone to blockages, ensuring processing capacity and screening efficiency. With its outstanding advantages, our Roller Screen is widely used in industries such as coal, chemical engineering, mining, and metallurgy.
II. Core Components
The core components of a Roller Screen include the screen box, drive unit, screen shaft assembly, and cleaning device.
Screen Box
The main body of the screen is welded from low-alloy high-strength structural steel. All screen shaft assemblies are fixed to the main body with connecting bolts. Wear-resistant liners are used to avoid direct contact between materials and the box, significantly extending the equipment’s service life. These liners are bolt-connected to the screen box for easy replacement.
Drive Unit
The drive unit adopts a single-shaft single-motor drive with shaft interlocking combined transmission. Reasonable power configuration and screen surface structure ensure uniform weight distribution within the screen, guaranteeing stable operation. The drive unit features a simple design for easy installation, with no movement of the connected screen shafts during operation. It is compact, lightweight, long-lasting, and has low maintenance costs.
Screen Shaft Assembly
The screen shaft assembly consists of a motor, speed reducer, screen shaft, screen disc, flat key, lock nut, coupling, bearing housing, and accessories. The drive motor connects to the speed reducer and screen shaft via a coupling. The screen shaft is designed for safety and rationality, effectively preventing bending or breaking. If any screen shaft fails, materials can still be pushed forward by the previous shaft, ensuring continuous screening. Bearing housings are installed on the outer side of the screen box for easy disassembly.
The Roller Screen uses parabolic screen discs with rounded edges to minimize rotational resistance. The discs are arranged in a staggered pattern for optimal design, offering high impact resistance without deformation or breakage and excellent wear resistance for long service life. The parabolic design maximizes material flow disturbance, improving screening accuracy and efficiency.
Self-Cleaning Device
The self-cleaning device for the screen shaft is made of wear-resistant media with a cutting edge inclined below the screen shaft. It automatically clears fibrous debris, sticky substances, and other materials adhering to the screen, addressing screen surface congestion issues.
III. Working Principle
The screening area is composed of multiple parallel roller shafts, each equipped with staggered screen discs that rotate in the same direction to achieve material feeding and screening. The screen surface of the Roller Screen is formed by parallel screen shafts, each uniformly fitted with special-shaped screen discs. These discs, with carefully designed curved surfaces, protrusions, or unique profiles, enable efficient screening during rotation. Driven by the drive unit, all screen shafts rotate synchronously in the same direction and at the same speed, with the discs working together to create a continuous rolling screen surface.
When materials enter the screen surface from the feed inlet, they begin to move forward due to friction and centrifugal force generated by the rotating discs. As the shafts continue to rotate, the materials tumble and loosen on the screen, gradually forming a uniform-thickness material flow with a certain acceleration, ensuring full dispersion and preventing accumulation or blockage. The gaps between the screen shafts and discs form screening holes, whose sizes can be adjusted as needed. Materials smaller than the screening holes fall through the gaps under their own gravity and the throwing force from the rotating shafts, becoming undersize materials. Larger materials are continuously pushed by the discs to the end of the screen surface, becoming oversize materials. In this way, the Roller Screen achieves precise and efficient material classification, playing a crucial role in mining, building materials, chemical engineering, and other industries to enhance material processing efficiency and quality.
IV. Our Company’s Technical Breakthroughs
Aiming at the pain points in coal processing, our company has improved and developed a series of patented technologies. The dedicated Roller Screen we launched effectively solves the technical challenges of underground coal recovery. Through continuous R&D and testing, we have addressed the shortcomings and defects of traditional roller screens:
Proposed a critical crushing analysis method for material jamming and shear under the meshing condition of the roller screen mesh, obtaining the force characteristics of rollers and screens during jamming to solve parameter setting issues for overload control systems.
Developed an automatic control technology for solving material jamming based on a self-recovering overload protection circuit, achieving automatic response to overload, automatic adjustment for foreign objects, and self-recovery.
Developed multi-stage variable speed flat screen equal-thickness roller screen technology and designed a wear-resistant cam screen differential tooth arrangement.
Developed the GZS series large high-efficiency Roller Screens, with a processing capacity of 300–3,800 tons per hour, which have been successfully applied at home and abroad, achieving good economic and social benefits.
V. Our Company’s Roller Screen
The main body of our Roller Screen is welded from Q355D low-alloy high-strength structural steel. All screen shaft assemblies are fixed to the Roller Screen with connecting bolts. Wear-resistant liners with a thickness of not less than 25mm are installed on the sides of the Roller Screen to prevent direct contact between materials and the box, greatly improving service life. The liners are bolt-connected to the box for easy replacement.
The screen shaft assembly includes a drive unit (motor + speed reducer), screen shaft, roller blade discs, flat keys, lock nuts, couplings, bearing housings, and accessories. The drive motor connects to the speed reducer and screen shaft via couplings. The screen shaft is made of 42CrMo forgings with CAE stress analysis for rational and safe design, effectively preventing gear roller bending or breaking. Special rubber bowl seals are used to ensure no dust leakage.
If any screen mesh fails, materials can be pushed over the faulty mesh by the previous mesh to continue screening. The roller screen discs are cast from wear-resistant manganese-chromium alloy steel, capable of withstanding impacts and wear from materials <800mm without deformation or breakage. The screen mesh surface has a hardness of HRC55 for good wear resistance, with screen shafts lasting no less than 30,000 hours and screen meshes no less than 12,000 hours.
Bearing housings for screen shafts are installed on the outer side of the screen mesh side plates for easy disassembly. All bearings use a forced lubrication system with centralized automatic lubrication via a grease pump, enabling automatic or manual timed and quantitative centralized lubrication.
Our company’s Roller Screen adopts a modular component design for quick and easy part replacement, facilitating maintenance and reducing downtime and maintenance costs. The fully enclosed structure operates without vibration, effectively preventing dust overflow, with low noise, energy conservation, environmental protection, and environmental friendliness.
VI. Conclusion
Our company’s Roller Screen incorporates advanced technology to effectively solve the technical challenges of underground coal recovery. It achieves automatic response to overload, automatic adjustment for foreign objects, and self-recovery, significantly improving processing capacity and screening efficiency, and achieving good economic and social benefits. Therefore, our company is highly confident in providing you with high-quality products and the best services.
