Common Faults of DTH Hammers and Handling Methods

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1. Loss of Hammer Action  

   Causes: Insufficient air pressure, blocked air passages, worn piston/seals.  

   Solutions: Verify air compressor settings and hoses for leaks, clean air passages with high-pressure air or flushing, replace damaged seals or pistons.

2. Reduced Penetration Rate  

   Causes: Worn/damaged drill bit, incorrect bit size/type, low air pressure, hard geological formations.  

   Solutions: Inspect and replace the bit, select bits suited to rock hardness, optimize air pressure/flow, and adjust drilling parameters.

3. Unusual Noises/Vibrations  

   Causes: Loose internal/external components, foreign debris, piston/cylinder wear.  

   Solutions: Tighten all connections, flush the system to remove debris, inspect and replace worn piston/cylinder liners.

4. Air Leakage  

   Causes: Damaged O-rings/seals, loose fittings.  

   Solutions: Replace seals regularly, ensure all connections are tightened to manufacturer specifications.

5. Hammer Stuck in Hole  

   Causes: Debris accumulation, unstable borehole walls, bit balling.  

   Solutions: Flush with air/water, use stabilizers for hole integrity, reverse rotation carefully, and avoid forcing the hammer.

6. Excessive Component Wear  

   Causes: Abrasive formations, lack of lubrication, misalignment.  

   Solutions: Use anti-abrasive bits, maintain proper lubrication (e.g., air-line oilers), ensure drill string alignment.

7. Broken Internal Parts (Piston/Check Valves)  

   Causes: Fatigue from cyclic stress, poor maintenance, improper use.  

   Solutions: Schedule regular inspections, replace parts per service life, avoid excessive feed pressure.

8. Bit Failure (Button Wear/Overheating)  

   Causes: Prolonged use, insufficient cooling, hard rock.  

   Solutions: Monitor bit condition, ensure adequate airflow for cooling, use bits with hardened inserts.

9. Check Valve Malfunction  

   Causes: Contaminated air, wear.  

   Solutions: Install air filters/dryers, clean or replace valves during maintenance.

10. Dust Emission at Drill Collar  

    Causes: Seal failure, excessive air pressure.  

    Solutions: Replace collar seals, adjust air pressure to optimal levels.

Preventive Measures  

Regular Maintenance: Disassemble, clean, and inspect components periodically.  

Lubrication: Use recommended oils to reduce friction.  

Alignment: Ensure straight drill strings to prevent uneven wear.  

Training: Educate operators on proper handling and troubleshooting.  

Air Quality: Use clean, dry air to avoid contamination.  

By addressing these faults proactively and adhering to maintenance protocols, DTH hammer efficiency and lifespan can be significantly enhanced.