Cage Crusher

Equipment Introduction

The cage crusher, also known as a squirrel cage crusher, cage-type crusher, or cage sand crusher, is a medium-sized horizontal cage bar crusher designed based on the principle of impact crushing. This equipment is widely used in numerous industrial sectors, including mining, metallurgy, building materials, highways, railways, water conservancy, chemicals, brick and tile production, and organic fertilizer and compound fertilizer production.

The cage crusher uses two opposing high-speed rotating cages to repeatedly impact materials, crushing them to a specific particle size. Its core advantages lie in its simple structure, high crushing efficiency, good sealing performance, stable operation, and ease of cleaning and maintenance. The equipment is particularly widely used in brick and tile factories because the crushed material has a high proportion of fine powder particles (≤0.2mm), which is beneficial for brick forming.

However, this equipment also has certain limitations, such as relatively small production capacity, high power consumption, frequent replacement of easily worn parts, and relatively high operating costs.

Equipment Structure

The cage crusher mainly consists of the following core components:

1. Casing and Base: Typically welded from thickened steel plates, the casing has internal linings to prevent wear. The base supports the entire transmission system.
2. Cage Rotor (Core Component): Composed of an inner and outer cage. The cage is formed by welding high-strength round steel bars (cage ribs) evenly spaced onto a disc. The inner and outer cages are concentrically arranged and nested within each other.
3. Transmission System: Includes two independent motors, pulleys, a drive belt, and bearing housings. The two motors drive the inner and outer cages to rotate at high speed in opposite directions.
4. Feed Hopper and Discharge Port: The feed hopper is located on the side of the machine (usually directly opposite the center of the inner cage), and the discharge port is located at the bottom of the machine.

Working Principle of the Equipment

The working principle of the cage crusher is based on the combined effects of impact crushing, material collision, and friction grinding. The specific process is as follows:

1. Feeding Stage:Material enters the central area of ​​the crusher (between two opposing rotating cages) through the feed inlet.

2. Impact Crushing Stage: The material first falls onto the innermost high-speed rotating steel bar, where it is initially crushed by the violent impact. Because the two cages rotate in opposite directions (one clockwise, one counterclockwise), the material is subjected to repeated impacts from both directions. The linear velocity of the steel bar is typically in the range of 25-40 m/s, while the circumferential velocity of the outer steel bar can reach 22-37 m/s.
3. Centrifugal Throwing and Collision Stage: Under centrifugal force, the crushed material is thrown outwards. The material is thrown towards the opposite rotating steel bar ring in the other cage, where it is impacted again. During this process, the material particles collide with each other, further crushing the material. The material also impacts and rubs against the inner wall and lining of the machine casing.
4. Staged Crushing and Discharge: The material passes through each ring of steel bars sequentially from the inside out, receiving an impact with each passing ring. After repeated impacts from all the steel bar rings, the material is crushed to the required particle size and finally discharged from the bottom of the crusher.
5. Particle size control principle:

The fineness of the powder is controlled by the distance between the two cages: the smaller the distance, the finer the powder, but the output is relatively lower.

Increasing the cage rotation speed and the number of steel rod rotations can make the product particle size finer.

However, if the rotation speed is too high, the material will not easily move from the center to the periphery, which will actually reduce productivity and accelerate the wear of the steel rods.

Applications of the Equipment

Cage crushers have a wide range of applications, mainly including the following:

1. Brick and Tile Industry and Building Materials Industry

Cage crushers are widely used in brick and tile factories, suitable for crushing soft and brittle materials such as industrial slag, dry clay, shale, and medium-hard coal gangue. The crushed material has a high proportion of fine powder particles, which is beneficial for brick forming. It can also be used for medium and fine crushing operations of limestone, coke, coal powder, and glassy ore.

2. Fertilizer and Chemical Industry: Cage crushers are core equipment in organic fertilizer, compound fertilizer, and chemical raw material production lines. They are widely used for crushing organic minerals, compound fertilizers, compound fertilizer granules, and other fertilizers. They can crush various single fertilizers with a moisture content below 6%, and are especially suitable for materials with high hardness. They are ideal crushing equipment for hard granules such as monoammonium phosphate (MAP), diammonium phosphate (DAP), and urea. The core application is in the secondary crushing (decomposition) stage of fermented materials in organic fertilizer production lines. They can crush semi-finished organic fertilizers such as composted livestock and poultry manure, composted straw powder, and mushroom residue to the fineness required for granulation.
3. Mining and Metallurgical Industry: Suitable for fine crushing of soft materials such as dry clay blocks, diatomaceous earth, chalk, asbestos ore, coal, and asphalt.
4. Multi-Industry Application: Widely used in mining, building materials, chemical, feed, food, pharmaceutical, and plastics industries, primarily suitable for crushing low-hardness materials.
5. Mixing and Crushing Function:The cage crusher can simultaneously mix and crush various raw materials, such as shale mixed with fly ash, industrial slag mixed with coal gangue, and clay mixed with fly ash, all with excellent results.

6. Applicable Scope and Boundaries

The cage crusher is mainly designed for brittle materials with medium to low hardness and for crushing fermented and decomposed organic fertilizer. It is not suitable for crushing the following materials:

High-toughness fibrous materials (such as incompletely decomposed straw containing long fibers, rubber, and plastics)

High-hardness rocks (quartzite, granite, etc., which will rapidly abrade the steel bars)

Materials with an initial moisture content >12% and a plastic paste-like consistency (easily clogging the bars, reducing efficiency, or even causing blockage).

Raw Material Requirements for the Equipment:

1. Hardness: Suitable for brittle materials (such as urea, ammonium phosphate, compound fertilizer lumps, coke, gypsum, etc.), not recommended for high-hardness ores.
2. Moisture: Highly adaptable to material moisture content, generally requiring the moisture content to be controlled below 15%. Excessive moisture can easily cause blockage of the cage gaps.
3. Particle Size: The feed particle size is generally required to be below 50mm to ensure crushing efficiency.

Operation and maintenance methods

1. Operating procedures: Two motors must be started first, and then feeding is allowed after the speed is stable; starting with load is strictly prohibited; feeding should be even and avoid piling up materials.
2. Lubrication maintenance: The bearing seat is a critical point and needs to be injected with high-temperature grease regularly, and is usually inspected once per shift.
3. Check the cage bars: Check the wear of the cage bars regularly. If the cage bars are severely deformed or worn and become thinner, it will affect the discharging granularity and dynamic balance and should be replaced in time.
4. Dynamic balance calibration: After repairing or replacing cage bars, dynamic balance calibration must be performed again to prevent severe vibration of the equipment.

Common Equipment Problems and Solutions

Application of equipment in production lines

1. Organic fertilizer and compound fertilizer production line

Cage crusher is the core equipment of organic fertilizer and compound fertilizer production line:

The fermented and decomposed organic fertilizer semi-finished products are subjected to secondary crushing (crushing)

Crush materials containing small lumps (lump diameter <80mm) to the particle size required by the process (usually more than 90% passes 40~60 mesh or particle size <1~3mm)

The discharged material is basically in the form of loose powder and can be directly entered into the next process (stirring or granulation) without screening.

The crushing ratio can reach i=10~50

For decomposed organic fertilizers with a slightly higher moisture content (≤8%~10%), it is less likely to cause clogging.

2. Production line configuration method

Can be used independently

Can be connected to batching machines, mixers, and granulators to assemble fully automatic production lines

The equipment supports continuous feeding, uninterrupted operation, and stable mass production 24 hours a day

It can meet the needs of organic fertilizer plants and organic-inorganic compound fertilizer companies with an annual output of 10,000 to 200,000 tons.

It can be used as a single unit or can be connected in two stages to obtain finer products.

3. Brick and building materials production line

Used for fine crushing of raw materials for brick making

Blending and crushing of multiple raw materials

It is suitable for the crushing of lime sand brick raw materials and the secondary crushing or return crushing section of small mineral processing plants.

4. Chemical industry and compound fertilizer production

Used for fine crushing of vitreous siliceous raw materials, soft limestone and coke

The oversized particles (oversize) screened out after granulation in the production of compound fertilizer are recycled and crushed

Handling lightly caked fertilizers such as potassium chloride and potassium sulfate

Target Customers for Cage Crusher

1. Organic and Compound Fertilizer Manufacturers

The production of organic and compound fertilizers is the primary demand for cage crushers. Fermented and decomposed organic fertilizer materials require secondary crushing (decomposition) to meet granulation requirements. This is especially suitable for small to medium-sized organic fertilizer plants with an annual production capacity of 10,000 to 200,000 tons.

2. Brick and Building Material Manufacturers

Brick and tile plants are a traditional application area for cage crushers. They need to finely crush raw materials such as industrial slag, dry clay, shale, and coal gangue. A high proportion of fine powder particles after crushing is beneficial for brick forming.

3. Fertilizer Manufacturers

Cage crushers are ideal for companies that need to crush monoammonium phosphate (MAP), diammonium phosphate (DAP), urea, and other fertilizer granules, especially when processing damp and caking fertilizer raw materials.

4. Chemical and Mining Enterprises

Companies that need to process brittle materials with medium to low hardness, such as limestone, coke, coal powder, and glassy ore. 5. Selection Recommendations

Small users: Models with an hourly output of 1-4 tons, suitable for laboratories and small processing plants.

Medium users: Models with an hourly output of 4-10 tons, suitable for small to medium-sized compound fertilizer plants and brick and tile factories.

Large users: Models with an hourly output of 10-15 tons, suitable for large-scale production bases.

Selection should be based on your industry, material type, and daily processing capacity, with a 10%-20% capacity margin.

Prioritize models equipped with wear-resistant steel rods and variable frequency speed control.

Technical Summary (Core Advantages)

The biggest advantage of the cage crusher lies in its dual-purpose operation for both dry and wet materials and its integrated crushing and mixing capabilities. Unlike hammer crushers, it doesn’t easily stick to the bottom due to material adhesion, and unlike roller crushers, it doesn’t suffer from uneven particle size distribution. For brittle materials with moderate moisture content, it is currently one of the most efficient and cost-effective dispersing solutions.

Cage crushers, as a classic impact crushing equipment, occupy an irreplaceable position in industries such as fertilizer, chemical, and building materials due to their advantages of simple structure, high crushing efficiency, and uniform particle size. Although traditional limitations such as rapid steel bar wear and high noise levels exist, the development of technologies such as dust-free operation, intelligent systems, and wear-resistant materials has significantly improved modern cage crushers in terms of environmental friendliness, reliability, and automation. When selecting a model, users should fully consider material characteristics, production capacity requirements, environmental requirements, and maintenance costs to choose the most suitable model for their production scenario. Through standardized operation and scientific maintenance, long-term stable and efficient operation of the equipment can be ensured.

We have been deeply involved in the fertilizer equipment field for many years, and our products cover process design, equipment manufacturing, installation, commissioning, and after-sales maintenance for multiple categories of production lines, including organic fertilizer, compound fertilizer, BB fertilizer (blended fertilizer), and bio-fertilizer, providing you with full-process services.