Common Issues and Troubleshooting Solutions for Desanders

To ensure the stable operation and efficient production of the desander, it is crucial to diagnose and troubleshoot faults promptly and accurately. This article provides a systematic explanation of common faults, their causes, and corresponding solutions.

I. Vibrating Screen System Faults

1. Screen cannot start

Phenomenon: After pressing the start button, the equipment shows no response.

Cause: Usually due to motor protection device activation (e.g., thermal relay tripping) or an open circuit/phase loss in the power supply line.

Solution: First, check and reset the motor protector; if ineffective, carefully inspect the electrical circuit to ensure secure connections and stable voltage.

2. Abnormal operation: insufficient amplitude, excessive swing, torsional vibration, abnormal noise

Phenomenon: Weak vibration, severe lateral swing, torsional motion of the screen body, excessive noise (>80 dB).

Cause: Typically related to the vibration motor, such as one motor not working or running in the wrong direction causing torque imbalance; misaligned eccentric blocks between the two motors; loose or damaged foundation bolts or internal bearings; aging/damaged or mismatched vibration isolation springs; loose screen mesh; cracks in the machine body.

Solution: Check all motors and ensure symmetrical counter-rotation; align and tighten eccentric blocks; fasten all bolts; replace damaged springs, bearings, or screens; weld or replace cracked structural parts.

3. Performance issues: unstable excitation force, no discharge

Phenomenon: Excitation force fluctuates, equipment sways, and material cannot be discharged properly.

Cause: Unstable power supply voltage or frequency; electrical circuit faults; loose eccentric blocks.

Solution: Test the power supply quality; repair the control system circuit; retighten the eccentric blocks.

4. Motor overheating and overcurrent

Phenomenon: Motor temperature rises quickly, and operating current exceeds rated value.

Cause: Bearing shortage of grease, damage, or seizure; single-phase operation or stator winding short circuit; excessive feeding load.

Solution: Re-grease bearings with proper lubricant or replace them; check and repair phase loss; overhaul motor; reduce feeding load to avoid overload.

II. Slurry Pump System Faults

1. Pump fails to suction water or slurry

Phenomenon: Pump does not suction water, flow is insufficient.

Cause: Air leakage at stuffing box; motor rotation direction incorrect; impeller damaged or suction pipeline/impeller channel clogged.

Solution: Tighten or replace packing; correct motor rotation; clean blockages; replace damaged impeller.

2. Excessive shaft power

Phenomenon: Motor load too high, current exceeds rated.

Cause: Stuffing box packing too tight causing friction heating; internal pump parts (impeller vs. liner) rubbing; flow exceeds efficient range; slurry density too high.

Solution: Loosen packing gland bolts; check and adjust pump clearances; regulate flow via valve or speed adjustment to rated condition; if slurry is too dense, reduce speed or dilute slurry.

3. Bearing overheating

Phenomenon: Excessive bearing housing temperature.

Cause: Too much or too little grease; contaminated or degraded grease; bearing damage.

Solution: Refill with correct amount of clean grease; clean housing and refill; replace damaged bearings.

4. Severe packing leakage

Phenomenon: Excessive leakage from pump stuffing box.

Cause: Worn packing; severely worn shaft sleeve.

Solution: Retighten or replace packing; replace shaft sleeve.

5. Pump vibration and loud noise

Phenomenon: Strong vibration and high noise during operation.

Cause: Damaged bearings; unbalanced worn impeller; air ingress or suction blockage; misalignment between motor and pump shafts.

Solution: Replace bearings; replace and rebalance impeller; eliminate air and clean suction line; realign motor and pump shafts.

III. Hydrocyclone and Screening System Faults

1. Poor separation efficiency of cyclone

Phenomenon: Little or no discharge from underflow, poor purification effect.

Cause: Underflow nozzle clogged; unstable or too low feed pressure (possibly due to pump suction blockage or air leakage at stuffing box).

Solution: Shut down to clean nozzle and storage tank; inspect slurry pump suction and stuffing box for blockage or leakage.

2. High moisture content in discharged solids from vibrating screen

Phenomenon: Discharged cuttings are too wet.

Cause: Oversized underflow nozzle of cyclone, resulting in diluted underflow; improper or clogged screen mesh; insufficient vibration force; improper screen deck inclination.

Solution: Replace with smaller nozzle; clean or use finer mesh screen; adjust vibration force; set screen deck angle to optimal position.

3. Slurry tank overflow

Phenomenon: Slurry overflows from storage tank.

Cause: Float valve stuck or malfunctioning; slurry pump fails to suction (see previous faults); pump speed too low (electrical issues); excessive upstream feed; blocked discharge pipeline.

Solution: Inspect, adjust, or replace float device; repair slurry pump; check motor voltage and frequency; reduce upstream feed; clean discharge pipeline.

IV. Electrical and Control Faults

Phenomenon: After pressing the start button, equipment (e.g., slurry pump) shows no response.

Cause: Thermal protector tripped; damaged components in control circuit (e.g., contactor, relay, button).

Solution: Reset thermal relay; have a qualified electrician inspect the control circuit and replace faulty components.

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