Hammer Crushers: An In – Depth Exploration

Hammer crushers are essential equipment in various industries, such as mining, cement production, and construction. They play a crucial role in reducing the size of materials, making them suitable for further processing or use. This article will comprehensively introduce hammer crushers, including their working principles, types, applications, advantages, disadvantages, and market prices.

Working Principles of Hammer Crushers

The basic working principle of a hammer crusher is to use the impact force generated by high – speed rotating hammers to break down materials. When the rotor rotates at high speed, the hammers strike the material inside the machine due to centrifugal and rotational forces. The material is crushed by the impact force of the hammers and then thrown against a surrounding surface, where it breaks into smaller pieces. The size of the pieces depends on the speed of the hammers and the strength of the material being crushed.

Components and Their Functions

• Rotor: The rotor is the main working part of the hammer crusher. It consists of a main shaft, hammer discs, pin shafts, and hammer heads. The motor drives the rotor to rotate at high speed, and the hammer heads on the rotor strike the material. The rotor needs to be made of high – strength materials to withstand the impact force and weight of the hammers and the material during the crushing process.
• Hammer Heads: The hammer heads are the key components for crushing the material. They are usually made of wear – resistant materials such as high – manganese steel or alloy steel. The shape and size of the hammer heads can affect the crushing efficiency and the size of the output particles. For example, claw – shaped hammer heads can provide a stronger impact force, while flat – shaped hammer heads can produce more uniform particles.
• Grate Screen: The grate screen is located at the bottom of the crusher. It is used to control the size of the crushed material. The material smaller than the gap between the grate bars can pass through the screen and be discharged, while the larger material is retained in the crusher for further crushing until it meets the size requirement.
• Feeding Hopper: The feeding hopper is where the material is fed into the crusher. It should be designed to ensure a smooth and continuous flow of material into the crushing chamber.

Types of Hammer Crushers

Single – Rotor Hammer Crushers

Single – rotor hammer crushers have one rotor with hammers attached. They can be further divided into irreversible and reversible types. Irreversible single – rotor hammer crushers are usually used for primary or medium crushing, where the material is crushed in one direction. Reversible single – rotor hammer crushers, on the other hand, can reverse the direction of the rotor, which is beneficial for evenly wearing the hammer heads and extending their service life. They are often used for fine crushing.

Double – Rotor Hammer Crushers

Double – rotor hammer crushers are equipped with two rotors, which can provide higher crushing efficiency and capacity. The two rotors can rotate in the same or opposite directions, depending on the design. These crushers are suitable for large – scale production and can handle materials with higher hardness and larger particle sizes.

Ring Hammer Crushers

Ring hammer crushers use ring – shaped hammers instead of traditional hammer heads. The rings are free to swing on the ends of the cross or fixed to the central rotor. As the rotor rotates, the rings strike the material and break it into smaller pieces. Ring hammer crushers are known for their high crushing ratio and are often used for crushing brittle materials such as coal, limestone, and gypsum.

Applications of Hammer Crushers

Mining Industry

In the mining industry, hammer crushers are used to crush various ores, such as iron ore, copper ore, and gold ore. They can break down large – sized ores into smaller particles, which are then further processed for extraction. For example, in an iron ore mine, a hammer crusher can crush the mined iron ore into a suitable size for subsequent grinding and beneficiation processes.

Cement Industry

Hammer crushers play a vital role in the cement industry. They are used to crush limestone, clay, and other raw materials for cement production. The crushed materials are then fed into a cement kiln for calcination. Hammer crushers can ensure a uniform particle size of the raw materials, which is beneficial for the quality and efficiency of the cement production process.

Construction Industry

In the construction industry, hammer crushers are used to process construction waste, such as concrete blocks, bricks, and asphalt. They can also crush natural stones, such as granite, basalt, and sandstone, into aggregates for use in concrete production, road construction, and building foundations. For instance, a hammer crusher can crush concrete blocks into small aggregates, which can be used as a substitute for natural sand and gravel in concrete production.

Chemical Industry

In the chemical industry, hammer crushers are used to crush various chemical materials, such as fertilizers, pesticides, and industrial salts. They can ensure the proper particle size of the chemical materials, which is important for their chemical reactions and applications. For example, in the production of fertilizers, a hammer crusher can crush the raw materials into a suitable size for better mixing and granulation.

Advantages of Hammer Crushers

High Crushing Ratio

Hammer crushers typically have a high crushing ratio, which means they can reduce the size of the material significantly in a single pass. This can simplify the crushing process and reduce the need for multiple crushing stages. For example, some hammer crushers can achieve a crushing ratio of up to 50, which is much higher than that of some other types of crushers.

High Production Capacity

These crushers are capable of handling large volumes of material, making them suitable for large – scale production. They can operate continuously for long periods, ensuring a stable supply of crushed material. For instance, a large – scale hammer crusher can have a production capacity of up to 1000 t/h, which can meet the high – volume production requirements of large mines and cement plants.

Simple Structure and Easy Maintenance

The structure of hammer crushers is relatively simple, consisting of a rotor, hammer heads, grate screen, and other components. This makes them easy to operate and maintain. The replacement of wearing parts, such as hammer heads and grate screens, is also relatively straightforward. For example, the hammer heads can be easily replaced when they are worn out, and the grate screen can be adjusted or replaced as needed.

Uniform Product Size

The crushed material produced by hammer crushers has a relatively uniform particle size. This is beneficial for subsequent processing and application. For example, in the production of concrete, the uniform particle size of the aggregates can improve the workability and strength of the concrete.

Disadvantages of Hammer Crushers

High Wear of Hammer Heads

The hammer heads of hammer crushers are subject to high wear, especially when crushing hard materials. This requires frequent replacement of the hammer heads, which increases the operating cost and downtime of the crusher. For example, when crushing granite, the hammer heads may wear out quickly, and they need to be replaced every few days or weeks, depending on the operating conditions.

Susceptible to Clogging

When crushing sticky or wet materials, the grate screen of the crusher is prone to clogging. This can reduce the production capacity and even cause the crusher to stop working. For instance, if the material contains a high amount of clay or moisture, it may stick to the grate screen and block the discharge port, resulting in a decrease in the crushing efficiency.

High Energy Consumption

Hammer crushers generally consume a relatively large amount of energy. The high – speed rotation of the rotor and the impact force required for crushing the material demand a significant amount of power. This can increase the operating cost of the crusher, especially in areas where the electricity price is high.

Market Prices of Hammer Crushers

The price of hammer crushers can vary widely depending on factors such as the type, capacity, brand, and features. On the market, small – scale hammer crushers can cost as low as a few thousand dollars, while large – scale industrial crushers can cost hundreds of thousands of dollars. For example, a basic small – capacity hammer crusher may cost around $1,000 – $5,000, while a high – capacity, high – performance crusher with advanced features can cost $100,000 – $500,000 or more.

Conclusion

Hammer crushers are important equipment in many industries, offering high crushing ratio, high production capacity, and uniform product size. However, they also have some disadvantages, such as high wear of hammer heads, susceptibility to clogging, and high energy consumption. When choosing a hammer crusher, it is necessary to consider the specific application requirements, the properties of the material to be crushed, and the budget. By carefully evaluating these factors, users can select the most suitable hammer crusher for their needs.