What are common faults in HDD drilling rig hydraulic systems?
Sep 15, 2025| 1. Abnormal Pressure
1. Insufficient Pressure
Symptom: Weak movement of the actuator (e.g., cylinder)
Cause: Hydraulic pump wear, relief valve failure (spring fatigue or valve core sticking), or valve blockage caused by oil contamination
Remedy: Replace worn pump parts or clean the relief valve; replace the spring if necessary.
2. Pressure Fluctuation
Symptom: Unstable system pressure
Cause: Air inlet to the oil line, clogged damping orifice, or abnormal oil viscosity
Remedy: Vent and clean the oil line, replace the oil pump with one that meets ISO VG 46 standard hydraulic oil
II. Abnormal Flow Rate
1. Insufficient Flow
Symptom: Slow actuator speed
Cause: Poor oil pump suction (filter clogged or oil level too low), stuck throttle valve
Handling: Clean the filter and refill oil to the standard mark. Check throttle valve operation.
2. No Flow Output
Symptom: Complete system inactivity
Cause: Worn hydraulic pump key leading to power transmission failure, or broken pressure relief valve spring
Handling: Replace the key or pressure relief valve assembly.
III. Abnormal Temperature
1. Excessive Oil Temperature
Symptom: Hydraulic oil temperature > 60°C
Cause: Poor heat dissipation (cooler clogged), system unloading circuit failure, oil oxidation
Handling: Clean the cooler, check unloading valve function, and replace aged oil.
IV. Leakage Contamination Failures
1. External Leakage
Symptoms: Oil leakage from pipe joints or seals
Cause: Deterioration of seals (O-rings/Glynn rings), loose threads
Action: Replace seals and tighten joints
2. Oil Contamination
Symptoms: Turbid oil or metal particles
Cause: Failed filter element or insufficient tank cleaning
Action: Replace the filter element and thoroughly clean the tank
V. Actuator Failure
1. Abnormal Cylinder Movement
Symptoms: Weak or stuck raising/lowering
Cause: Worn piston seals or loose nut causing piston to fall off
Action: Replace the seals and re-tighten the piston nut
2. Delayed Valve Response
Symptoms: Asynchronous operation between operating commands and actions
Cause: Stuck solenoid valve or control signal interference
Action: Clean the valve core or check the electrical circuit
