How Does the Crusher in Coal Feeder Breaker Adjust Discharge Size
Introduction
Equipment definition and positioning
The working principle of the coal Feeder Breaker is to continuously convey the raw ore to the crushing chamber through the feeding module. After the particle size reduction is completed by the internal core components, it is directly discharged to the downstream equipment without the need for additional transfer links.
The crushing component, as the core crushing unit of the coal Feeder Breaker, is mainly composed of the rotor, broken teeth and Impact Plate. The rotor is connected to the motor through the V-belt. The broken teeth are evenly distributed and fixed on the rotor, and rotate synchronously with the rotor to form crushing kinetic energy. The impact liners are arranged around the rotor, forming a relative crushing space with the broken teeth. The sieve plate/grate plate is installed at the bottom of the crushing chamber, forming the discharge channel and playing a role in particle size screening at the same time. During operation, after the materials enter the cavity, they are crushed by the coordinated action of the high-speed rotating broken teeth, the impact liners, the screen plates/grates, and are finally discharged through the screen plates/grates.
Adjust the target
The particle size of the output from the crushing component is adjusted by regulating key structural and operational parameters to change the average particle size distribution of the material. It is necessary to ensure that the proportion of particles in the output that meet the requirements of the downstream process reaches the design standard. This not only avoids subsequent equipment failures caused by excessive coarse particles but also prevents energy waste and efficiency decline due to over-crushing. Ultimately, it achieves a precise match between the output quality and the downstream process.
The particle size control factors of crushing components
Analysis of the crushing process
The material crushing in the crushing chamber is the result of the combined action of impact, shearing and collision.
The impact effect stems from the instantaneous strike of the high-speed rotating broken teeth on the material, using huge kinetic energy to break through the internal bonding force of the material, causing it to shatter instantly.
The shearing effect occurs between the broken teeth and the impact liner, screen plate/grate plate. The material is held between the relatively moving parts and is cut into fine particles by the shearing force.
The impact effect includes the mutual collision between the crushed materials and the secondary impact between the materials and the inner wall of the cavity and the surface of the components, further refining the particle size.
The intensity and synergistic effect of the three functions are directly determined by the structural parameters of the cavity and the operating status of the equipment, jointly influencing the final output particle size.
Three main parameters affecting particle size
The gap between the hammerhead and the impact liner
The minimum distance between the end of the broken teeth’s rotation trajectory and the impact liner directly determines the number of impacts of the material in the cavity. The smaller the gap, the more easily the material is intercepted by the impact liner after being struck by the broken teeth, resulting in multiple reciprocating impacts, more thorough crushing and finer output particle size. The larger the gap, the fewer times the material is impacted, and it can pass through the cavity quickly. The particle size of the discharged material is relatively coarser.
The minimum gap between the broken teeth and the sieve/grate plate
The minimum distance between the broken teeth and the surface of the screen plate/grate plate during rotation is a key parameter for controlling the particle size of the output. Materials with particle sizes smaller than this gap can pass through and be discharged smoothly, while those larger than this gap are retained in the cavity and continue to be crushed until the particle size meets the requirements. The accuracy of this directly affects the uniformity of the discharged particle size.
The aperture or gap width of the sieve plate/grate plate itself
The direct factors restricting the maximum output particle size. No matter what fineness the material is crushed to in the cavity, the maximum particle size finally discharged cannot exceed the width of the aperture or gap. Different specifications of aperture designs correspond to different requirements for the discharge particle size.
Influence of operating parameters
The higher the rotor linear speed, the greater the kinetic energy obtained by the broken teeth, the stronger the impact strength on the material, and the harder the material can be crushed, with finer output particle size. However, excessively high linear speed will increase energy consumption and broken teeth wear. The feed particle size needs to match the crushing capacity of the coal feeder breaker. If the feed particle size is too large, it may exceed the crushing limit of the broken teeth, resulting in insufficient crushing and coarse output. If the feed particle size is too small, it is easy to cause excessive crushing, increase energy consumption and reduce production efficiency.
Core regulatory mechanism
Adjustment and replacement of the gap between grate and screen plates
Structural principle
The adjustment and replacement of the grate plate/screen plate are mainly achieved through two designs: adjustable grate plates and replaceable screen plates. The adjustable grate plate adopts a hydraulic drive or mechanical bolt positioning structure. The hydraulic drive type moves the grate plate laterally or longitudinally through a hydraulic cylinder, precisely adjusting the gap with the broken teeth. The mechanical bolt positioning type achieves gap fixation by adjusting the fixed position of the grate plate installation bracket and using bolt locking. The replaceable sieve plate adopts a modular design and is fixed to the bottom of the cavity through a quick connection interface. Sieve plate modules with different hole diameters or gap widths can be replaced according to the particle size requirements.
Adjustment operation
Adjustment method
The position of the grate plate is adjusted through the hydraulic system or mechanical bolts to change its distance from the broken teeth’s rotation trajectory. When the distance is reduced, the path length of the material in the crushing zone increases, the number of impacts and shears it undergoes increases, and the particle size of the discharged material becomes finer. When the distance is increased, the material passage speed speeds up, the number of crushing times decreases, and the particle size of the discharged material becomes coarser.
Replacement method
When it is necessary to significantly adjust the maximum output particle size, after the machine stops, the original screen plate can be disassembled through the quick interface and replaced with a new screen plate corresponding to the pore size specification. The maximum output particle size is directly limited, with high adjustment accuracy and convenient operation.
Effect evaluation
Gap adjustment has a direct impact on the output rate of fine materials and energy consumption. Reducing the gap can increase the proportion of fine material output, but the retention time of the material in the cavity is prolonged, the crushing load increases, and the energy consumption per unit material (specific energy consumption) rises. Increasing the gap can reduce energy consumption, but the output rate of fine materials will decrease accordingly. In actual operation, it is necessary to balance the output rate of fine materials and energy consumption based on the downstream process requirements and select the optimal gap parameters.
Adjustment of the clearance of the impact liner
Reduce the gap
By adjusting the mechanism to reduce the distance between the liner and the broken teeth, the number of impacts of the material in the cavity is increased. After multiple reciprocating impacts, the particle size of the material becomes finer, which is suitable for scenarios where the downstream process has a high demand for fine materials.
Increase the gap
By increasing the distance between the liner and the broken teeth, the number of impacts on the material can be reduced, excessive crushing can be avoided, and the output particle size will be coarser. This is especially suitable for processing soft or sticky materials and can effectively prevent the material from adhering to the liner and causing blockage.
The influence of broken teeth wear and maintenance
Wear and tear consequences
The broken teeth is a core vulnerable part in the crushing process. Long-term use will cause wear at the end due to impact and friction with the material, reducing the effective impact radius. This change will directly lead to an increase in the actual working clearance between the broken teeth and the grate/liner. Even if the theoretical clearance remains unchanged, it will cause a decrease in crushing strength and a coarser drift of the output particle size. In addition, the uneven wear of the broken teeth can also cause the rotor to rotate unevenly, resulting in the vibration of the feeder breaker, accelerating the wear of other components, and further affecting the crushing effect.
Maintenance measures
To ensure the stability of particle size, it is necessary to strengthen the maintenance and management of broken teeth. Regularly inspect the wear condition of the broken teeth. For symmetrical structure broken teeth, the unworn surfaces can be turned over for use to extend their service life. When the wear exceeds 30% of the original size, the broken teeth should be replaced in time to restore the effective impact radius. For wear-resistant material broken teeth, the worn parts can be repaired by surfacing welding to restore their geometric shape. At the same time, during maintenance, it is necessary to check the balance status of the rotor to avoid equipment vibration caused by uneven wear of the broken teeth.
Precautions and troubleshooting in practical applications
Safety regulations during the adjustment process
Particle size regulation involves mechanical structure operation and electrical equipment operation, and safety regulations must be strictly followed. Before adjustment, the feeder breaker needs to be locked and de-energized to prevent accidental startup. Isolate the dangerous areas around the crushing cavity and set up warning signs to prohibit non-operating personnel from entering. Operators must wear personal protective equipment such as safety helmets, protective gloves and safety shoes. When using hydraulic or electrical regulating mechanisms, it is necessary to check in advance whether the pressure and current are normal. After the regulation is completed, conduct a no-load test run first to confirm that there are no abnormalities before putting it into load operation.
Feedback on the regulation effect based on material properties
High humidity/viscous materials
This type of material is prone to adhering to the holes or gaps of the screen plate/grate plate, causing blockage. Even if the gap is adjusted to a smaller value, the actual output particle size will still be coarser due to the blockage of the channel. It is necessary to increase the frequency of cleaning the screen plate or adopt a screen plate design with self-cleaning function to reduce material adhesion.
High-hardness materials
It will accelerate the wear rate of the broken teeth and the impact liner, causing the gap to increase rapidly and the stability of the output particle size to decline. High wear-resistant material broken teeth and liners should be selected, and the interval calibration and maintenance cycle should be shortened to ensure stable crushing effect.
Troubleshooting
When the output particle size fails to meet the expected target, the following priority order should be followed for troubleshooting: First, inspect the screen plate/grate plate to see if there is any pore blockage, component wear and deformation or gap offset, which are the most common causes of failure; Secondly, inspect the impact liner to confirm whether the gap between it and the broken teeth is accurate, and whether the liner is worn or loose. Finally, inspect the broken teeth to check the degree of wear, whether the effective impact radius meets the standards, and whether there are any problems such as loosening or breakage. Based on the investigation results, measures such as cleaning, adjustment and replacement should be taken to restore the effect of particle size control.
Conclusion
The regulation of the output particle size of the crushing component in the coal Feeder Breaker is a systematic process based on precisely controlling the geometric dimensions of the crushing cavity and the number of strikes on the material. The core achieves precise control of the output particle size by adjusting the gap between the broken teeth and the impact liner, screen plate/grate plate, replacing screen plates/grates of different specifications, and combining with reasonable operating parameters and broken teeth maintenance.
