Introduction: The working principle of an impact crusher. The so-called impact crushing refers to the selective crushing of an object in its natural cracks, bedding planes, joint surfaces and other weak parts under the impact force in a free state. It is different from the impact force on objects in a constrained state in hammer crushing, and is different from other shear, compression, and grinding crushing processes. Therefore, it has the lowest energy consumption in the crushing process, and due to its selective crushing ability, it plays a role in separating useful minerals and obtaining more cubic products.

The impact crusher, which applies the principle of impact, uses a high-speed rotating hammer to impact the material in the crushing chamber at high speed, causing the material to undergo impact crushing and causing the impacted block to be rushed towards the impact plate at high speed. After the material is subjected to another impact crushing, it bounces back from the impact plate to the impact area of the hammer head and repeats the above crushing process. At the same time, the material travels back and forth between the hammer head and the impact plate, There is also a collision and impact effect between them. When the particle size of the crushed material is smaller than the gap between the hammer head and the impact plate, it is discharged from the lower part of the machine as the crushed product.

The crushing energy of materials with different particle sizes varies, and the smaller the material, the greater the energy required for crushing due to the gradual reduction of internal defects. According to the formula between energy and linear velocity: A=mra.

With the improvement of mining capacity, the size of the material blocks continues to increase after mining, while the single rotor impact crusher has limited the increase in feed particle size due to its own structural rationality and other reasons. Therefore, a double rotor impact crusher has been developed. In order to improve the function of the second rotor, a double rotor impact crusher with height difference setting was developed. According to the relationship between hammer wear and energy consumption and the linear speed of the rotor, the first rotor roughly crushes the material at a lower speed, while the second rotor finely crushes the material at a higher speed, improving the crushing ratio.

Vertical impact crusher is a representative of the impact crusher used in finely crushing materials. We know that the wear of the hammer head increases nonlinearly with the increase of the linear velocity of the hammer head's rotation. However, during fine crushing, the linear velocity of the hammer head is very high, and relatively lightweight materials cannot enter the effective strike zone of the high-speed rotary hammer head (which is precisely within the maximum linear velocity range), leading to a decrease in crushing effect and an intensification of hammer head wear. The vertical impact crusher adopts a central feeding method, where the initial speed of the fed material is close to zero, and gradually accelerates before being ejected from the rotor body for impact crushing, improving the impact crushing effect and reducing the wear of vulnerable parts. This type of crusher has evolved into two categories: mechanical and self lining.

Application of Impact Crusher

As mentioned above, the impact crusher has uneven discharge and is prone to "large blocks" in actual use. The impact hammer crusher can easily solve these problems.

The material is fed from the feeding port into the working area of the hammer head, and is crushed by the impact of the high-speed rotating hammer head. At the same time, the material is further crushed by the high-speed impact on the impact plate, and bounces back from the impact plate to the working area of the hammer head. The above crushing process is repeated, and finally enters the hammering area (the working area between the hammer head and the castor strip), where it is further subjected to the hammering and grinding effects of the hammer head on the castor strip. Practice has proven that materials are not fully crushed in one cycle of the rotor, but rather undergo multiple cycles before being fully crushed. Large blocks of material may not be fully crushed during the impact process. The crushing can be achieved through the rolling action between the impact plate and the hammer plate, which has been confirmed by actual experiments (in the absence of castor bars, the maximum product particle size does not exceed the gap size between the hammer plate and the impact plate).