Quick Reference for Common Rice Huller Faults
As a key piece of equipment in rice processing lines, rice hullers inevitably encounter various faults during long-term continuous operation. Timely and accurate diagnosis and correct solutions are crucial for maintaining production efficiency and product quality. This article summarizes the most common fault symptoms, cause analysis, and solutions.
Fault 1: Significant Drop in Hulling Rate
Description: Single-pass hulling rate drops from normal levels above 85% to below 80%, with significantly increased return flow.
Possible Causes and Solutions:
| Cause | Check Method | Solution | |-------|-------------|----------| | Worn Rolls | Visual inspection for smoothness, scratches | Replace or regrind rolls | | Excessive Roll Gap | Measure gap with feeler gauge | Reduce gap to 0.5-1.0mm | | Reduced Speed Difference | Measure fast and slow roll speeds | Check belt tension and transmission parts | | Uneven Feeding | Observe material distribution at inlet | Clean feeder, adjust baffles | | Excessive Paddy Moisture | Test with moisture meter | Dry or sun paddy to 13.5%-15% |
Fault 2: Excessive Broken Rice Rate
Description: Broken rice in discharged brown rice exceeds 3%, even reaching above 5%.
Cause Analysis and Treatment:
Roll Gap Too Small
- Signs: Very high hulling rate but excessive broken rice, high motor current
- Treatment: Slightly increase roll gap, adjusting no more than 0.1mm at a time
Paddy Moisture Too Low
- Signs: Husks become brittle, brown rice easily breaks during hulling
- Treatment: Humidify paddy to increase moisture to around 14%
Uneven Local Roll Wear
- Signs: Broken rice fluctuates periodically
- Treatment: Check roll surface flatness, replace if necessary
Hard Impurities Entered
- Signs: Sudden increase in broken rice, possibly with abnormal sounds
- Treatment: Stop immediately, clear impurities, check for roll damage
Fault 3: Abnormal Equipment Noise
Normal vs Abnormal Noise:
- Normal operation: 75-85 decibels
- Sudden sharp, dull, or irregular noises are abnormal
Common Noise Causes:
1. Bearing Damage
- Sound: Continuous "humming" or metal friction
- Signs: Significant temperature rise at bearing, possibly exceeding 70°C
- Solution: Replace bearing, check shaft neck for wear
2. Foreign Material on Roll Surface
- Sound: Periodic "thumping"
- Signs: Unstable hulling effect
- Solution: Stop and clean roll surface, check pre-cleaning equipment
3. Drive Belt Slippage
- Sound: High-frequency "squealing"
- Signs: Speed fluctuations, unstable hulling rate
- Solution: Adjust belt tension or replace belt
4. Loose Components
- Sound: Metal impact or vibration noise
- Signs: Significantly increased vibration
- Solution: Stop and tighten bolts, check shock absorption
Fault 4: Excessive Grain in Husk
Standard: Normal should be below 0.5%; investigation needed if exceeding 1%.
Main Causes:
Insufficient Airflow
- Check fan speed is normal
- Clean accumulated bran in air ducts
- Adjust damper opening
Uneven Air Velocity Distribution
- Check for damage or air leaks in ducts
- Adjust deflector positions
- Clear discharge outlet blockages
Uneven Mixture Particle Size
- Check feeding uniformity
- Adjust roll gap for consistent hulling
Fault 5: Feeding Problems or Blockages
Symptoms: Material堆积 at inlet, irregular discharge speed.
Troubleshooting Steps:
- Check for bridging in feed hopper (material clumping)
- Check if feeder (vibrator or screw) works normally
- Check if feed pipe is blocked
- Confirm if paddy is excessively wet or contains long straw
Preventive Measures:
- Maintain appropriate paddy moisture
- Remove long straw in pre-cleaning
- Regularly clean feeding devices
Fault 6: Motor Overheating or Abnormal Current
Current Abnormality Guide:
| Current State | Possible Cause | Action | |--------------|----------------|--------| | Consistently High | Gap too small, bearing damage | Increase gap, check bearings | | Periodic Fluctuation | Uneven feeding, uneven rolls | Adjust feeding, check rolls | | Sudden Increase | Hard object jam, blockage | Stop immediately for inspection | | Below Normal | Belt slippage, idling | Adjust belt, check feeding |
Daily Preventive Maintenance Checklist
Per Shift (every 8 hours):
- [ ] Check feeding uniformity
- [ ] Listen for abnormal operation sounds
- [ ] Check motor temperature (< 60°C)
- [ ] Clean equipment surface dust
Weekly Checks:
- [ ] Check roll surface condition
- [ ] Check belt tension and wear
- [ ] Tighten all bolts
- [ ] Check lubrication status
Monthly Checks:
- [ ] Measure roll gap
- [ ] Check bearing temperature and sounds
- [ ] Clean accumulated bran in air ducts
- [ ] Check electrical control system wiring
Emergency Stop Conditions
Stop immediately if:
- Burning smell detected (possible motor or bearing overheating)
- Violent metal impact sounds heard
- Current suddenly exceeds rated value by 120%
- Severe vibration or equipment displacement
- Smoke or sparks observed
Professional Support
For complex electrical faults, mechanical damage, or recurring issues, contact professional maintenance personnel. Zhejiang Lianggong provides comprehensive after-sales service:
- Technical Hotline: 0575-87335525
- On-site Repair: Covering major grain-producing areas
- Parts Supply: Common parts shipped within 48 hours
- Remote Diagnosis: Online fault troubleshooting assistance
Proper daily maintenance and standardized operation are fundamental to reducing rice huller faults and extending equipment life. For more maintenance knowledge, visit our website or call for consultation.
