I. Judging Wear by Changes in Component Dimensions
The most direct evidence of wear is a change in the geometric dimensions of key components, especially areas in direct contact with high-concentration slurry:
1. Underflow Inlet (Sand Settling Inlet)
This part is prone to inner diameter expansion due to continuous erosion by coarse particles. Normally, its outlet is a regular circle; if the inner wall is found to be smoothly expanded, the edges thinned, or the shape is irregular, and the measured diameter exceeds the original size by 0.2mm, it should be considered excessive wear and must be replaced.
2. Feed Inlet
Long-term tangential impact from high-speed slurry can wear the original rectangular or circular inlet into an irregular ellipse, disrupting the initial rotation of the fluid and leading to a decrease in classification efficiency. This can be judged by visual inspection after shutdown or by measuring with calipers and comparing with the original drawings.
3. Hydrocyclone Tube Inner Wall and Conical Section
Especially in the lower part of the cone, high-frequency particle impact can cause increased surface roughness and even grooves. If the surface feels noticeably uneven to the touch, or if the lining material (such as polyurethane or ceramic) shows signs of peeling or cracking, it indicates severe wear.
✅ Recommendation: Establish a regular inspection system, measuring key dimensions every 800–1000 hours of operation and recording trends.
II. Identifying Wear Signs Through Operational Performance Even without disassembling the equipment, the degree of wear can be indirectly judged by the system's operating status:
1. Decreased Separation Efficiency This manifests as the presence of unwanted coarse particles in the overflow ("overflow coarseness"), or fine starch particles in the underflow, indicating instability in the centrifugal field. This is often caused by the underflow orifice widening or inner wall wear leading to flow field distortion.
2. Reduced Underflow Concentration During normal operation, the underflow should be a thick, umbrella-shaped discharge. If the underflow becomes thinner, discharges in a rope-like or columnar form, and the concentration remains below 45% (e.g., in one iron ore case, it dropped from 45% to 28%), it is likely due to the inner diameter of the sand settling port increasing after wear.
3. Abnormal Pressure and Flow Rate
Although the feed pressure is normal, a decrease in throughput or the need for higher pressure to maintain the same flow rate may indicate increased energy loss due to wear and deformation of the internal flow channels.
4. Frequent Blockage or Unstable Discharge
Weared, irregular surfaces are more prone to material accumulation or eddies, leading to localized blockages or discharge fluctuations, affecting system continuity.
III. Preventive Maintenance and Countermeasures
To avoid cascading failures caused by wear, the following measures are recommended:
1. Use Wear-Resistant Materials: Under high-wear conditions, prioritize the use of ceramic-lined feed inlets or polyurethane cyclone tubes, which can extend service life by 8–10 times.
2. Regularly Replace Wear Parts: Treat underflow inlets, O-rings, etc., as regular spare parts and proactively replace them based on operating time or test results to avoid sudden failures.
3. Optimize Operating Parameters: Control the feed concentration within a reasonable range (≥4°Be) to avoid excessively high flow rates that exacerbate erosion; use a variable frequency pump to stabilize the feed and reduce pulse impacts.
4. Shutdown Inspection: During each major overhaul, disassemble the hydrocyclone tubes and comprehensively assess the inner wall, connections, and sealing condition, repairing or replacing them promptly.
📌 Tip: For multi-stage systems, pay special attention to the first-stage (coarse separation) and final-stage (refining) hydrocyclones, as these two stages experience the most severe wear and directly affect the overall process performance.
