The advantages and characteristics of Mineral sizer in coal crushing process

Introduction

In the coal processing industry, the crushing operation plays a crucial role. It directly affects coal sales and the investment in subsequent processing stages, which is closely tied to the economic benefits of coal enterprises. The deeper development of the market economy and advancements in coal washing equipment have raised new and higher requirements for traditional crushing operations. These requirements include the need for crushing equipment to ensure strict product size, minimal over-crushing, simple structure, high reliability, and low maintenance costs for components.

The Mineral Sizer, with its new technology and structure, effectively meets these demands. Its unique crushing principle and adjustable crushing chamber design ensure strict control over product size and reduce over-crushing.

Structural Features of the Mineral Sizer

Components

The main components of the Mineral Sizer include the drive unit (which consists of dual motors, a hydraulic coupling, a gearbox, a self-aligning drum-shaped gear coupling), the crushing rolls (including roll shafts and crushing tooth rings), comb plates, the machine body, centralized lubrication system, and detection and control devices.

Drive Unit

The drive unit provides the power for the Mineral Sizer. Each crushing roll has its own independent drive unit, which can be adjusted to the optimal crushing speed based on the material to be crushed and the desired particle size. The hydraulic coupling can buffer the excessive shock and torque generated during crushing, providing overload protection, and has features for fuse and explosion protection.

Crushing Rolls

The crushing rolls, including the roll shafts and crushing tooth rings, are the main working parts of the Mineral Sizer. The highly plastic roll shafts can withstand the bending stresses generated during the crushing of high-strength materials. The crushing tooth rings are welded with spiral-arranged crushing teeth. The tooth tips are designed to be eagle-beak shaped, which helps reduce energy consumption and over-crushing. The tooth rings have high strength and wear resistance. The comb plates of the Mineral Sizer are fixed to the sides of the crushing frame, with hard-wearing crushing teeth welded onto the surface. The distance between the comb plate and the tooth rolls can be adjusted according to the material, achieving different crushing requirements.

Machine Body

The machine body of the Mineral Sizer is a powerful frame structure. The side plates, front panel, and motor are all installed together with the base. The parts exposed to friction during crushing are protected by liners. The structure is robust, offering excellent stability and ensuring that the crushing forces are confined to the upper part of the body, minimizing the dynamic load on the foundation and ensuring the machine’s stability during operation.

Centralized Lubrication System

The bearings of the Mineral Sizer’s crushing rolls are lubricated using a centralized lubrication system, which reduces labor intensity and is safe, reliable, and convenient. A positive-pressure grease seal is set at the bearing seals to improve the reliability of the roll bearing seals.

Technical Features of the Mineral Sizer

Dual Function of Crushing and Screening

The mineral sizer is equipped with a spiral-shaped crushing teeth arranged on the tooth roller. The two rollers move relative to each other, resembling a rotating sieve, which can screen out the materials smaller than the product size and crush the large pieces of materials. This avoids the defect of impurities from the crushed materials contaminating the mineral sizer. It has the dual functions of crushing and screening. Within a certain range, it can independently complete the crushing and screening operations without the need for a separate screening device, simplifying the system and saving investment.

Extremely Low Over-Crushing

The mineral sizer crushes the materials by utilizing the principle of shearing, rather than the compression, impact or other principles used by traditional crushers. During the crushing process, materials smaller than the product size directly pass through the gap of the teeth rollers of the mineral sizer without undergoing crushing action, while only materials larger than the size requirement are crushed. Therefore, it has an extremely low rate of over-crushing. For medium-hard materials such as coal and coke, the over-crushing rate is generally around 13%, which can significantly enhance the economic benefits of the user unit and is the preferred crushing equipment for crushing operations of medium-hard materials such as coal and coke.

Ensuring Product Size

The Mineral Sizer uses a fixed center distance to force material through the crushing rolls. The roll’s structure and size are designed based on the required product size, strictly controlling the space through which the material passes. This guarantees uniform product size, minimal fines, energy savings, and a long service life. After the crushing teeth wear out, they can be welded or the tooth tips can be replaced on-site, making maintenance quick and inexpensive.

Overload Protection

The Mineral Sizer eliminates the long gear drives and retreating systems found in traditional crushers, reducing intermediate energy consumption and failure points. The operation is simple, with fully symmetric rolls that are interchangeable. In addition to an overload protection system, the coupling has fuse and explosion protection functions. The drive unit is further protected by shear pins at the external teeth of the half-couplers, ensuring the unit is protected if the Mineral Sizer becomes jammed.

Adjustable Center Distance

The center distance of the Mineral Sizer, combined with different tooth configurations, determines the maximum feed size for efficient material crushing. The crushing chamber length can be adjusted according to different processing capacities, and the design can allow for either adjustable or fixed center distance. By adjusting the center distance, the gap between the crushing rolls can be changed to control the product size, meeting different production requirements.

Operation and Maintenance

Operation

To ensure the safe and stable operation of the Mineral Sizer, its management and maintenance must be strengthened. Before starting, operators should read the equipment’s operation log and clear any material from the crushing chamber to ensure sufficient oil supply.

The Mineral Sizer should be started without load and fed only after reaching normal speed without abnormalities to ensure uniform feeding and prevent overload. It is prohibited to feed iron or wood debris into the Mineral Sizer.

If any abnormal sounds, temperature rises, or odors are noticed during operation, the machine should be stopped immediately, and the issue should be addressed before restarting.

Before stopping the machine, feeding should be stopped, and any material in the crushing chamber should be cleared.

Maintenance

Strengthen the daily maintenance and regular inspection of the mineral sizer. Every week, check the tightness of each connecting bolt and the working conditions of the reducer and motor.

Monthly check the wear condition of the crushing teeth. If the tooth part is severely worn, it should be repaired by welding or replaced in time to ensure adequate oil supply for the reducer and hydraulic coupling and the good working condition of the monitoring and control device.

Analyze common faults, take effective solutions and handling methods, establish a preventive maintenance system and a file for the replacement cycle of vulnerable parts.

Conclusion

As market demand continues to grow and technology progresses, the Mineral Sizer has become an excellent solution. With its modular design, overload protection drive unit, adjustable crushing rolls, and centralized lubrication system, the Mineral Sizer ensures stable and efficient operation.