Impact crusher is widely used in road construction, metallurgy, mining, building materials, transportation and other engineering technology fields. It organically combines the crushing principles of striking, counterattack, centrifugal impact, shearing and grinding, so as to make full and effective use of its energy and crushing cavity. It can crush hard materials with compressive strength more than 300 MPa, and has the characteristics of large crushing ratio and good product granularity, which makes the impact crusher play an important role in many crushing machines.

The crushing effect of impact crusher has a very important impact on the quality of finished materials. This paper mainly shares the factors that affect the effect of impact crushing and how to improve the production capacity.

Factors affecting the effect of impact crushing

1, rotor rotation speed

The research of rotor rotation speed can guide the impact crusher to select the appropriate rotation speed when crushing materials with different particle sizes and materials, so as to prevent the material from being excessively broken, and also help to reduce energy consumption. The higher the rotor speed is, the greater the impact force will be when the hammer contacts with the material. With the increase of rotating speed, the greater the impact force is, the better the impact crushing effect is and the higher the damage degree is Therefore, the interaction force between hammer and material, material and impact plate will be smaller when the subsequent shear fracture occurs.

2. Rotor moment of inertia

Generally, each type of impact crusher can crush a certain range of materials, which is largely related to the size of the rotor moment of inertia installed in the crusher. In the case of the same rotor speed, different rotary inertia rotors can provide different crushing force, that is, the crushing capacity is different, which directly affects the performance of the crusher.

When the material is crushed by impact, the greater the moment of inertia of the rotor at the same speed, the greater the impact crushing force of the hammer on the material and between the material and the impact plate When the material is sheared and broken, the smaller the reaction force on the impact plate, the more likely the material will be sheared.

3. Angle of impact plate at all levels

The angle of each impact plate has a great influence on the effective crushing force when the stone impacts the impact plate. Generally, the force perpendicular to the contact interface is called the effective crushing force, that is, the force that can cause the stone to be broken. The most ideal situation is that the stone can be perpendicular to the impact plate every time it collides with the impact plate, and the impact and shear fracture of the material are caused by the impact plate with different angles The effect of the method is also great.

• Reducing the angle of the first impact plate has a good effect on the material shear crushing, but it is not conducive to the impact crushing of the material;

• Increasing the angle of the first impact plate can increase the number of impact impact and enhance the impact crushing effect, but it is not conducive to the shear fracture of materials.

Methods to improve the capacity of counterattack

1. Reduce the humidity of materials reasonably

If the moisture content in the material is large, the material is easy to adhere in the crushing cavity, and it is also easy to block in the blanking process, thus reducing the production capacity of impact breaking. Therefore, for the material with large moisture content, we can take the way of drying or drying in advance to reasonably reduce the humidity of materials and improve the capacity of counterattack crushing.

2 pre screening materials in advance

If the material before crushing contains a large amount of large ores, the crushing time of materials in the crushing chamber will be increased, and the capacity of counterattack crushing will be reduced to a certain extent. If there is a lot of fine powder in the material before crushing, the capacity of impact crushing will be reduced. Because these fine powder will be easy to adhere, affect the conveying and cutting. Pre screening materials in advance, screening out large and powdery materials for processing, so that the materials entering the crushing chamber can meet the design requirements of impact crushing, and effectively improve the production capacity of impact crushing.

3. Reasonable increase of main motor power

In the range of rated motor power, the higher the main motor power, the higher the production efficiency and production capacity. Therefore, in production, the main motor power can be increased within the allowable range to improve the production capacity of the impact breaker.

4 properly increase the speed of the rotor

The rotor speed is one of the important working parameters of the impact crusher, which plays a decisive role in the production capacity, product size and crushing ratio of the crusher. The test results show that with the increase of rotor speed, the production capacity and crushing ratio of impact crusher are significantly increased, and the particle size of products is relatively fine. However, with the increase of rotor speed, the power consumption also increases, the wear of plate hammer is accelerated, and a certain production cost is increased. Therefore, in the production can not blindly pursue the high speed of the rotor, speed increase to be appropriate.

5. The angle of impact plate should be appropriate

At present, there are Broken line and circular arc impact plates 。 The angle of each impact plate has a great influence on the effective crushing force produced by the impact of the material on the impact plate, and also on the impact and shear crushing effect of the material.

The structure of broken line impact plate is simple However, it can not guarantee the most effective impact crushing of the ore. therefore, when purchasing and debugging the impact breaking, we must pay attention to the angle of the impact plate, Try to make the material perpendicular to the impact plate when it collides with the impact plate, so as to improve the capacity of impact breaking 。

Arc shaped impact plate There are more commonly used involute linear, the characteristics of this structural form At each point of the impact plate, the ore is impacted in the vertical direction, and the crushing efficiency is higher And higher production capacity.