I. Common Fault Types and Main Causes
1. Overflow with Coarse Particles (Coarse particles mixed in the overflow)
Symptom: The overflow liquid is turbid and contains coarse starch particles that should not be present.
Main Causes:
Bottom outlet blockage: Coarse particles cannot be discharged normally and are forced into the overflow;
Insufficient feed pressure or excessive feed concentration affects the stability of the centrifugal force field.
Solution: Immediately stop the machine, check and clean the bottom outlet, and confirm whether the discharge nozzle is worn or blocked.
2. Low Bottom Flow Density
Symptom: The bottom flow is thin, and the starch concentration is insufficient.
Main Causes:
Discharge nozzle size is too large or worn;
Incorrect feed conditions, such as unstable pressure or low concentration.
Solution: Replace with a discharge nozzle of the appropriate size and check the operation of the feed pump.
3. Hydrocyclone Blockage
Symptom: Decreased flow rate, abnormally high pressure, or no bottom flow discharge. Main Causes:
Incorrectly matched materials (e.g., sand, gravel, fiber clumps) entering the system;
Residual starch after long-term shutdown, leading to drying and blockage.
Solution: Check the front-end screening equipment to ensure material purity; rinse thoroughly with clean water after shutdown.
4. Abnormal Equipment Vibration
Symptom: Obvious machine vibration accompanied by noise.
Main Causes:
Excessive material quantity or high proportion of coal dust;
Dry suction or uneven feeding;
Deformed or unstable overflow pipe.
Solution: Adjust the feed rate, use a suction pipe to prevent dry suction, and replace the overflow pipe if necessary.
5. Significant Fluctuations in Operating Pressure
Symptom: Pressure gauge pointer swings frequently, indicating system instability.
Main Causes:
Mismatch between pump and hydrocyclone, resulting in uneven feeding;
Air bubbles or cavitation within the system.
Solution: Isolate the hydrocyclone for pressure balancing, or reset the pump speed.
6. Failure to Form a Fan-Shaped Discharge (Abnormal Sand Settling Morphology)
Phenomenon: The underflow is discharged in a rope-like or columnar shape, rather than the ideal umbrella-shaped diffusion.
Main Causes:
The tank level is too low or the inlet gate is not fully open;
Inappropriate pressure settings, mismatched pump frequency.
Solutions: Raise the slurry tank level and adjust the pump frequency to a stable operating condition.
II. Preventive Maintenance Recommendations
To reduce the occurrence of malfunctions, the following daily maintenance measures are recommended:
Regular Cleaning: After each shutdown, flush the cyclone pipe and cavity with clean water to prevent starch deposition;
Inspect Wear Parts: Pay special attention to the wear of the underflow nozzle, overflow pipe, and O-ring seals. Replace any parts exceeding 0.2mm of their original diameter;
Monitor Process Parameters: Record the feed pressure, concentration, and temperature in real time, and adjust promptly if deviations are found;
Standardize Operating Procedures: Never start the machine without water. Before starting, ensure all valves are in the correct position.
✅ Tip: For multi-stage cyclone systems, it is recommended to establish a system of inspection every shift, focusing on monitoring the infeed and discharge status of the first and last stages to ensure the stable operation of the entire system.
