Are there any safety risks when using air compressors after long-term idle use?

Re-using air compressors after long-term idle activities does pose safety risks, and safety needs to be ensured through professional evaluation and standardized operation. The following is a systematic explanation from three aspects: equipment status changes, potential risk points, and preventive measures:

1. Analysis of changes in equipment status

1. Rust of metal parts
   If metal parts (such as cylinders, pistons, and valves) inside the air compressor are deactivated in a humid environment for more than 3 months, the surface oxide film may be damaged, resulting in a 30%-50% increase in the roughness of the contact surface. Rust products accelerate the aging of seals and increase the risk of leakage by 40%.

2. Lubricating system degradation
   During the shutdown period, lubricating oil will deposit due to gravity, and the thickness of the oil film formed on the inner wall of the oil system will be reduced by 60%. When the ambient temperature fluctuates more than ±10℃, the oil viscosity change rate can reach 25%, resulting in insufficient lubrication in the early stage of start-up.

3. Electrical system moisture
   When the humidity in the control cabinet exceeds 60% RH, the insulation resistance value may drop by 20% per month. For equipment that has been suspended for more than 6 months, the incidence of poor contact with electrical components has tripled.

2. Identification of potential risk points

1. Risk of mechanical seizure
   Rusted parts may generate 200%-300% of the rated torque at the moment of starting, causing frequent action of the motor overload protection device. If the protection fails, the motor may burn out.

2. Risk of pipeline burst
   The corrosion rate of the inner wall of compressed air pipes that have been left standing for a long time accelerates, and the pressure bearing capacity decreases. When the system pressure reaches 80% of the rated value, leaks may occur in pipe sections with corrosion pits deeper than 0.5 mm.

3. risk of secondary pollution
   Condensate water at the bottom of the air storage tank mixes with rust products to form oily deposits, which may be brought into the pneumatic system when re-activated, causing stuck actuator components or product contamination.

3. Preventive operating practices

1. Special inspection before commissioning

• Perform 3 no-load start-up tests at an interval of 15 minutes each time, and observe whether current fluctuations are within ±5% of the rated value
• Use an endoscope to inspect the sealing surface of the air valve and confirm that there are no corrosion pits exceeding 0.2mm
• Conduct insulation resistance test on the electrical control loop, and the required value is ≥1MΩ

2. Lubricating system activation

• Replace all lubricating oils, and the new oils must meet ISO VG 68 standard
• The manual turning gear shall not be less than 5 revolutions, and confirm that the rotating parts are not stuck.
• Keep running at low speed (50% of rated speed) for 30 minutes after startup and monitor oil temperature changes

3. Pressure system debugging

• The loading pressure is divided into 3 stages: 0.3MPa→0.6MPa→ rated pressure, and each stage is held for 20 minutes
• Check the tripping pressure of the safety valve and set it to 1.05-1.1 times the rated pressure
• Conduct penetration testing on all welded joints to confirm that no cracks are displayed

4. Follow-up maintenance enhancement

• Drain condensate from the air storage tank every week in the first month of operation, and at least twice a month thereafter
• Check the oil content of compressed air every 500 operating hours, ≤1ppm
• Establish equipment health files and record key parameters such as vibration data and temperature distribution

The re-activation of air compressors after long-term shutdown must follow professional procedures. Through systematic inspection and progressive debugging, safety risks can be reduced by more than 90%. It is recommended to formulate standardized operating procedures and equip professional testing instruments to ensure that the equipment is always in a controllable state.