Common Fault Analysis and Treatment of Piston Compressors  

Analysis and Treatment of Insufficient Discharge Capacity  

1. Intake System Issues

   (1) Clogged Air Filter: Long-term operation leads to filter fouling, increasing suction resistance. Regular cleaning or replacement is required—recommended inspection every 500 operating hours.  

   (2) Improper Piping Design: Suction pipes exceeding 10 meters or undersized diameters cause pressure loss. Piping should be redesigned to standards, with diameters one size larger than the compressor intake port.  

2. Mechanical Wear Issues

   (1) Cylinder-Piston Assembly Wear:  

   Cast iron piston-to-cylinder clearance: 0.06‰~0.09‰ of cylinder diameter.  

   Aluminum alloy piston: 0.12‰~0.18‰.  

   If wear exceeds limits, rebore the cylinder or replace the liner.  

   (2) Piston Ring Failure: Replace if the end gap exceeds twice the design value. During installation, stagger ring gaps.  

3. Sealing System Leakage  

   (1) Packing Leakage:  

   Check alignment (radial runout ≤ 0.05 mm).  

   For graphite packing, apply moderate preload.  

   (2) Valve Leakage:  

   Replace valve plates if wear exceeds 0.3 mm.  

   Spring force should be appropriate; valve lift must meet design specifications.  

Temperature Anomaly Treatment  

1. Excessive Discharge Temperature

   (1) Cooling System Inspection: Clean intercoolers if heat exchange efficiency drops by >10%. Maintain cooling water ΔT at 5–8°C.  

   (2) Interstage Leak Detection: If pressure ratio abnormally rises by >0.2 MPa, inspect piston rings and valve seals.  

2. Bearing Overheating  

   (1) Bearing contact area ≥ 60% (check via bluing).  

   (2) Lubricant Selection:  

   Summer: ISO VG68  

   Winter: VG46  

   Oil pressure: 0.15–0.4 MPa.  

Pressure Anomaly Diagnosis  

1. Pressure Monitoring System  

   (1) Install real-time monitoring for discharge pressures at all stages.  

   (2) Allowable fluctuations:  

   Primary stage: ±0.05 MPa  

   Secondary stage: ±0.08 MPa  

2. Troubleshooting Flow  

   (1) First, inspect downstream equipment.  

   (2) Then, check valves and piston rings in the current stage.  

   (3) Finally, evaluate compression efficiency of preceding stages.  

Mechanical Noise Diagnosis  

1. Sound Characteristics

   (1) Metallic knocking (high frequency): Likely from valves.  

   (2) Dull thudding (low frequency): Likely from bearings.  

2. Vibration Analysis  

   (1) Use vibration analyzers.  

   (2) Normal vibration ≤ 4.5 mm/s.  

Crosshead System Maintenance  

1. Crosshead Pin Assembly

   (1) Taper fit contact area ≥ 80%.  

   (2) Axial play ≤ 0.03 mm.  

   (3) Align lubrication holes with oil passages.  

2. Shoe Clearance Adjustment  

   (1) Top clearance: 0.0015 × crosshead diameter (D).  

   (2) Side clearance: 2 × top clearance.  

Crankshaft System Precision Repair  

1. Bearing Inspection Standards  

   (1) Babbitt thickness ≥ 1.5 mm.  

   (2) Contact angle: 60–90°.  

   (3) Backlash: 0.02–0.05 mm.  

2. Alignment Requirements  

   (1) Radial runout ≤ 0.05 mm.  

   (2) Axial play ≤ 0.10 mm.  

   (3) Levelness ≤ 0.05 mm/m.  

Piston Assembly Maintenance  

1. Piston Rod Inspection

   (1) Straightness ≤ 0.05 mm/m.  

   (2) Surface hardness: HRC 50–55.  

   (3) Apply threadlocker to fasteners.  

2. Piston Assembly

   (1) Measure cylinder clearance with feeler gauges.  

   (2) Stagger piston ring gaps by 120°.  

   (3) Tighten bolts with torque wrenches.  

Vibration Fault Resolution  

1. Diagnostic Steps

   (1) Measure foundation vibration.  

   (2) Check anchor bolt tightness.  

   (3) Verify alignment.  

2. Dynamic Balancing  

   (1) Residual unbalance ≤ 1 g·cm/kg.  

   (2) Secure balancing weights.  

Lubrication System Maintenance  

1. Oil Management

   (1) Quarterly oil analysis.  

   (2) Water content ≤ 0.1%.  

   (3) Contaminants ≤ 0.05%.  

2. Oil Circuit Checks  

   (1) Replace filters if ΔP ≥ 0.15 MPa.  

   (2) Oil cooler ΔT ≤ 15°C.  

Preventive Maintenance System  

1. Maintenance Schedul  

   (1) Daily: Oil level, temperature, pressure.  

   (2) Monthly: Valves, fasteners.  

   (3) Annual: Full disassembly inspection.  

2. Key Parameter Tracking  

   (1) Maintain operational database.  

   (2) Set alarm thresholds.  

   (3) Conduct trend analysis.  

Conclusion  

Piston compressor troubleshooting requires systematic thinking. Enterprises should establish a comprehensive equipment management system encompassing daily checks, periodic maintenance, condition monitoring, and fault analysis. Preventive maintenance can reduce sudden failures by >60% and improve overall efficiency by >15%.