The Impact of "over Iron" on The Service Life of Lining Plates And Preventive Measures

During the operation of the cone crusher, "over iron" - that is, metal objects such as iron blocks that cannot be broken entering the crushing chamber - is one of the main factors that endanger the health of the equipment. These metal debris may come from shovel teeth, drill bits that fall off during the mining process, or tools left behind during maintenance. When the iron block enters the crushing chamber, it will directly cause damage to the lining plate (rolling mill wall and crushing wall). This article is based on on-site cases and industry experience, systematically elaborating on the impact of "over iron" on the service life of lining plates and corresponding preventive measures.

1、 The specific impact of "over iron" on the service life of lining plates

1. Causing cracks and abnormal failure of the lining plate

When the iron block enters the crushing chamber, due to the strength and hardness of the metal far exceeding that of the ore, it cannot be crushed normally and will be stuck between the moving cone liner and the fixed cone liner. At this moment, when the device attempts to break it, a rigid collision will occur, causing a sudden increase in pressure.

This rigid collision will generate a huge local impact load on the surface of the lining plate, causing the local stress of the lining plate material to instantly exceed its strength limit. Frequent iron passing can easily cause crushing and cracking of the fixed cone lining plate, thereby shortening the service life of the lining plate and increasing spare parts consumption. In production practice, cracks in the lining plate caused by excessive iron often appear in the early stages of use, which is a typical abnormal failure mode.

2. Causing looseness and uneven wear of the lining plate

At the moment of passing iron, the operating power and hydraulic pressure of the crusher will sharply increase, and the discharge port will suddenly enlarge. During this process, the impact force distribution borne by the lining plate is extremely uneven. If the size or shape of the iron block is large or irregular, it may get stuck on one side of the crushing chamber, causing excessive force on one side.

This biased force may cause the clamping ring or locking bolt of the locking lining plate to loosen. Once the lining plate begins to loosen, it will further intensify wear and even damage the contact surface between the cone and the lining plate during subsequent crushing operations.

3. Accelerated lining wear and failure

In addition to direct crack damage, excessive iron can indirectly accelerate the normal wear and failure of the lining plate. When the iron block is stuck in the crushing chamber, it will cause the main shaft and the eccentric copper sleeve to form rigid contact and friction with each other. This abnormal friction will intensify the overall vibration of the equipment, causing the lining surface to bear additional impact loads and accelerating the fatigue peeling process of the material.

On site data shows that by reducing the load operating power and pressure release values, the service life of dynamic and fixed cone liners can be extended. This also indirectly confirms the negative impact of the instantaneous power and pressure surge caused by excessive iron on the lifespan of the lining plate.

2、 Quantitative analysis of the impact of "over iron" on the service life of lining plates

In order to gain a more intuitive understanding of the impact of iron on the lifespan of lining plates, the following table summarizes the main forms of damage and their manifestations:

The specific manifestation of damage types and their impact on the lifespan of lining plates

Cracks damage the surface of the dynamic cone or fixed cone liner, directly leading to the scrapping of the liner and shortening its service life

Loose and worn clamping ring, increased clearance between lining plate and cone, intensified lining plate wear, may damage cone surface

Fatigue accelerated vibration intensifies, fatigue peeling on the lining surface accelerates wear rate and shortens replacement cycle

Unbalanced wear caused by iron block jamming, resulting in severe wear on one side of the lining plate and excessive local wear, leading to the destruction of the shape of the lining plate

After optimizing the iron protection measures, a certain beneficiation plant reasonably reduced the load operating power and pressure release value, significantly extending the service life of the dynamic and fixed cone liners, and the main shaft body did not show obvious wear.

3、 Preventive measures for "over iron"

1. Improve the configuration of iron removal equipment

In the crushing production line, configuring an effective iron removal device is the primary measure to prevent excessive iron. The specific methods include:

Installation of electromagnetic iron remover: Install disc or belt type electromagnetic iron remover at key conveyor belt positions to adsorb iron components mixed in materials.

Using metal detectors: Install iron sensors at the front end of the iron remover, interlocked with the belt start button. When large pieces of scrap iron exceeding the working capacity of the iron remover are detected, the belt conveyor can be automatically stopped and safely picked up manually.

Set up screen protection: Install a screen at the feeding port of the crushing equipment to separate the iron blocks that have not been removed by the iron remover or manually picked up, and then clean them manually.

The comprehensive method of human-machine iron removal can effectively reduce the iron passing rate of the crusher. Practice has proved that after adopting the above measures, the average iron passing rate of the crusher can be controlled at a lower level.

2. Optimize the parameters of the iron protection system

Different types of cone crushers are equipped with corresponding iron protection devices:

Spring type cone crusher: When the iron block enters the crushing chamber, the iron protection system will make the support sleeve move upward, compress the spring or safety cylinder, make the fixed cone move upward, expand the discharge port, and automatically reset after the iron block passes through.

Hydraulic cone crusher: equipped with a cleaning cylinder and a locking cylinder hydraulic safety system, it can lift the support sleeve and fixed cone by releasing the hydraulic cylinder at the moment of passing iron, automatically discharge the iron block, and achieve fault handling without dismantling the machine.

The following optimization measures can be taken for device parameters:

Reduce the iron pressure protection value appropriately from the design value, so that it can not only provide iron protection, but also ensure that the equipment operates under normal load

Reduce the release value of load operation power and pressure to alleviate the impact of iron overload on equipment

3. Improve oil temperature monitoring and interlock protection

When passing through the iron, the main shaft is skewed due to the compression of the iron block, causing hard friction with the copper sleeve, which can lead to a rapid increase in the temperature of the main lubricating oil. To address this phenomenon, the following measures can be taken:

Lowering the oil temperature alarm value: Appropriately lowering the main lubricating oil temperature protection alarm value from the original design to provide early warning

Add conveyor belt interlock: When the oil temperature reaches the alarm value, the feeding conveyor belt will automatically stop, allowing the crusher to idle and cool down

Install sound and light alarms: Install sound and light alarms in the operating room to promptly remind personnel on duty to take corresponding actions

After improving the oil temperature protection system in a certain beneficiation plant, the consumption of related components in 5 crushers decreased by about 70% compared to before the improvement.

4. Standardize emergency inspections after passing iron

When there is a sudden metal impact sound, a sharp increase in operating pressure, or a sudden amplification of the discharge port during the operation of the crusher, it indicates that iron has passed and the following inspection measures must be taken immediately:

Check whether the operating parameters of the crusher, such as power, pressure, oil temperature, and discharge port, are normal through the display screen

Check whether the connecting bolts and stoppers of the upper and lower frames are loose

Check for leaks in the oil pipes, and for alarm signals in the fuel tank instrumentation system and automatic control system

Stop the machine and check if the safety coupling shear pipe has been cut or displaced

The crusher has stopped due to iron overload. It is necessary to check whether the shear tube is intact and whether the iron in the crushing chamber has been discharged. It is strictly prohibited to restart immediately

5. Strengthen management and personnel training

In addition to technical measures, prevention at the management level is equally important:

Establish an assessment system: Develop an equipment iron passing assessment system to enhance the sense of responsibility of operators

Strengthen inspection: Regularly check the operation of iron removal equipment to ensure its normal operation

Train operators: Familiarize them with the correct handling methods when handling iron to avoid secondary damage caused by improper operation