Bearings For Cement Industry

Introduction to rotary kiln

The rotary kiln is a rotating calcining kiln that belongs to the category of building materials equipment, according to the different materials processed. Rotary kilns are classified into three types: cement kilns, metallurgical chemical kilns, and lime kilns.

Cement kilns are used for calcining cement clinker and are categorized into two types: dry-production cement kilns and wet-production cement kilns.

Metallurgical chemical kilns are mainly used in the metallurgical industry, such as magnetization roasting of lean iron ore in steel plants, oxidation roasting of chromium and nickel-iron ore, roasting of high-alumina vanadium ore in refractory materials plants, roasting of clinker and aluminum hydroxide in aluminum plants; roasting in chemical plants Chromium ore and chromium ore powder and other similar minerals.

Limekiln (i.e., activated lime kiln) is used for baking activated lime, and light-burned dolomite is used in steel plants and ferroalloy plants.

Rotary kiln bearings are a vital component of rotary kiln equipment. They carry the weight and operation of the entire kiln body. At the same time, they are in harsh working environments such as high temperature, high load, and high corrosion. Therefore, the quality and quality of the bearings are very important. Performance has extremely high requirements. This article will introduce in detail the characteristics, structure, material selection, and maintenance of rotary kiln bearings.

• Characteristics of rotary kiln bearings

• Rotary kiln bearings usually work under high temperatures, heavy load, and high-speed conditions, so they have the following significant characteristics:

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• High speed and heavy load: The rotation speed of rotary kiln bearings is usually very high, and they need to bear the huge weight of the kiln body and impact load. It requires the bearings to have high load-bearing capacity and high-speed and heavy-load characteristics.

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• High-temperature resistance: The working temperature of the rotary kiln is usually very high, so the bearings need to be able to work stably in high-temperature environments. Some advanced bearing materials, such as high-temperature alloys and ceramic bearings, can maintain good performance at high temperatures.

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• Corrosion resistance: Rotary kiln bearings will be exposed to various chemicals and corrosive gases during work, so they must have good corrosion resistance.

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• High reliability: Since the shutdown and maintenance of the rotary kiln will have a significant impact on production, the bearings are required to have extremely high reliability to ensure long-term stable operation.

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• Maintainability: In order to facilitate the maintenance and replacement of equipment, the design of rotary kiln bearings should be easy to disassemble and replace so that they can be repaired or replaced when damage occurs.

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• The structure of rotary kiln bearings

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• Rotary kiln bearings usually consist of inner rings, outer rings, rolling elements, and cages. The inner ring cooperates with the shaft and rotates with the shaft. The cage evenly separates the rolling elements to reduce friction and wear between them, while the outer ring cooperates with the body. The rolling elements mainly have spherical, cylindrical, and conical shapes and cooperate with the inner ring and outer ring to form a raceway.

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• Material selection for rotary kiln bearings

• The choice of materials greatly influences the performance and quality of rotary kiln bearings. Common bearing materials include high-quality low-carbon steel, medium-carbon steel, and high-carbon steel, such as GCr15, GCr15SiMn, and GCr4. These materials can achieve the requirements of high hardness and high fatigue resistance through appropriate heat treatment and surface treatment. In some special cases, in order to improve the bearing capacity and high-temperature resistance, high-temperature alloy and ceramic bearing materials can be selected. These materials have high-temperature strength and chemical stability, allowing them to maintain good performance in high temperatures and corrosive environments.

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• Selection of rotary kiln bearings

• When selecting rotary kiln bearings, you need to consider the following factors:

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• Working conditions: It is necessary to understand the working environment of the bearing, such as temperature, humidity, atmosphere, impact load, and vibration. These conditions will affect the service life and reliability of the bearing, so the selection needs to be based on the actual situation.

• Bearing size: Bearing size and construction type need to be considered. Bearings of different sizes and types have different load-carrying capacities and service lives. It is necessary to select the appropriate bearing size and type according to actual needs.

• Accuracy grade: The accuracy grade of the bearing needs to be considered. The higher the accuracy level, the smoother and more reliable the bearing operation, but the higher the manufacturing cost. The appropriate accuracy level needs to be selected based on actual needs.

• Performance: The performance and maintenance costs of the bearing need to be considered, including lubrication performance, anti-wear performance, anti-fatigue performance, service life, etc. It is necessary to select suitable bearing materials and heat treatment methods according to actual needs to ensure the best balance between bearing performance and maintenance costs.

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• In short, as a key component of rotary kiln equipment, rotary kiln bearings need to have the features of high speed and heavy load, high-temperature resistance, corrosion resistance, high reliability, and easy maintenance.