Wear in parallel zone of cone crusher: mechanism and systematic control of wall thickness thinning and product particle size coarsening

As a key equipment for medium and fine crushing, the working efficiency and stability of the cone crusher largely depend on the shape of the crushing chamber formed by the crushing wall and the rolling bowl wall. Among them, the abnormal rapid wear of parallel zones (parallel bands) is a core issue that leads to equipment performance degradation and increased operating costs. Specifically, this is manifested by a significant thinning of the wall thickness in this area, which directly causes the product particle size to become coarser. Understanding the causes and impacts of this phenomenon is the foundation for implementing effective technical management.

1、 The Function of Parallel Zones and the Necessity of Wear and tear

Parallel zone refers to the section in the lower part of the crushing chamber where the crushing wall is approximately parallel to the rolling mill wall and the gap is constant. Its core functions are twofold:

Ensure crushing ratio: Squeeze the material that has been preliminarily crushed in the upper chamber area multiple times to ensure that it meets the set particle size requirements.

Stable discharge: Control the discharge of materials in a controlled state to ensure uniform particle size distribution of the product.

It is precisely because of its functional positioning that the parallel zone bears the densest layer crushing effect. The material is repeatedly squeezed here, and the particle size has become smaller with sharp edges, causing continuous high stress grinding on the wall surface. Therefore, compared to the feed zone and transition zone of the crushing chamber, the higher wear rate in the parallel zone is an inherent objective phenomenon determined by the working principle of the equipment.

2、 The cause of increased wear and tear: anomalies beyond inherent laws

Under the recognized high wear background, multiple factors will interact with each other, resulting in abnormal thinning of the parallel zone wall thickness that far exceeds expectations.

1. Improper setting of operating parameters and feeding conditions

Setting the closed edge discharge port (CSS) too small: Setting the discharge port too small in pursuit of finer product granularity will greatly increase the pressure and friction work in the parallel zone, leading to exponential wear.

Mismatch between feeding particle size and cavity shape: Continuous feeding of material particles that are too large or have a high proportion of "slender materials" can easily cause blockage or abnormal stress concentration in the parallel zone, exacerbating local wear.

Uneven distribution of feed: The material was not evenly distributed along the circumference of the crushing chamber, resulting in excessive local contact pressure between the crushing wall and the rolling mill bowl wall, leading to eccentric wear.

2. Direct impact of material characteristics

The abrasiveness (such as quartz content), hardness, moisture content, etc. of crushed materials directly affect the wear rate. Highly abrasive materials can quickly cut metal surfaces.

3. Self factors of wear-resistant components

Material performance mismatch: The parallel zone requires the material to have good compressive strength, surface hardness, and a certain degree of toughness to resist high stress grinding and micro impact. If the material selection is improper (such as too high hardness but insufficient toughness, which is prone to micro peeling, or too low hardness, which is prone to rapid cutting), it will shorten the service life.

Geometric accuracy and assembly quality of components: The initial profile accuracy of the crushing wall and rolling bowl wall, as well as their concentricity after assembly, determine whether the parallel zone gap is truly uniform. Any initial deviation can lead to local point contact, causing rapid wear.

3、 Core consequence: From thinning of wall thickness to deterioration of system performance

The thinning of parallel zone wall thickness is not an isolated event, it can trigger a chain of technical problems:

Product granularity control failure: wall thickness reduction is directly equivalent to the actual size increase of the closed edge discharge port (CSS). Even if the hydraulic adjustment system of the discharge port is not activated, the actual discharge particle size will continue to thicken, and the particle size distribution range will become wider, resulting in a decrease in the pass rate.

Deterioration of production capacity and energy consumption: To compensate for the coarsening of particle size, operators may tend to adjust the discharge port setting value, but this will further increase load and wear, and may reduce throughput. The equipment may enter the "over iron protection" state more frequently, causing interruptions in the production process and an increase in energy consumption per unit of product.

Risk of secondary failure: Severe uneven wear can disrupt the even distribution of crushing force, leading to increased equipment vibration and abnormal stress on key load-bearing components such as spindles and bushings, shortening their service life.

4、 Systematic Control and Management Strategy

A systematic approach is required to control the wear of parallel zones, managing the entire process from monitoring, material selection, operation to maintenance.

1. Establish a precise wear monitoring and prediction system

Regular measurement and filing: Utilize downtime to regularly measure and record the wall thickness of key sections in parallel zones. Establish a wear time curve file for each set of lining plates, summarize the wear patterns applicable to specific material conditions, and provide a basis for predictive replacement.

Particle size analysis reverse inference: using online or offline product particle size analysis as a daily monitoring tool. When the particle size continues to increase and other factors are excluded, the wear condition of the parallel zone should be checked first.

2. Optimize the selection of wear-resistant components and cavity design

Material selection for adaptability: Based on specific material characteristics, materials with better resistance to high stress grinding can be selected, such as improved high manganese steel, specific alloy steel, or professional wear-resistant alloys.

Cavity design and optimization: Different cavity designs (standard, medium, thin, etc.) determine the length and angle of the parallel zone. It is crucial to choose a cavity shape that matches the target crushing ratio and feed particle size. Modern design can optimize the cavity curve to make the wear distribution more even and extend the overall service life.

3. Standardized operation and implementation of proactive maintenance

Stable operating parameters: On the premise of meeting the requirements of product granularity, set a reasonable size of the closed edge discharge port to avoid overly tight operation. Ensure continuous, uniform, and consistent feeding within the designed particle size range.

Implement lining plate replacement/rotation system: For some designs, when the parallel zone is heavily worn on one side, the crushing wall or rolling bowl wall can be rotated by a certain angle (such as 180 °) in the middle stage, and the unworn or lightly worn area can be used to continue working. This is an economically effective measure to improve the service life of the entire lining plate.

Ensure assembly accuracy: When replacing the liner, it is necessary to ensure that all mating surfaces are clean, free of old liner residue or damage, and strictly follow the regulations for zinc or resin filling to ensure a stable fit between the liner and the body, avoiding impact wear caused by looseness.