I. Quick diagnosis process
Measure vibration value
Use vibration meter to detect the amplitude of each part (normal value should be <7.1mm/s, more than 12mm/s requires emergency treatment)
Record vibration frequency characteristics (low frequency/high frequency)
Preliminary judgment type
Vibration characteristics Possible causes
Low-frequency vibration (<10Hz) Unstable foundation/poor centering
High-frequency vibration (>100Hz) Bearing wear/rotor imbalance
Periodic impact vibration Cylinder wear/loose connectors
II. Mechanical cause treatment plan
1. Foundation installation problem
Handling measures:
Check the anchor bolt torque (need to reach ±5% of the equipment calibration value)
Use epoxy resin grouting material to re-cast the foundation (thickness ≥150mm)
Install shock pads (rubber isolators with natural frequency <5Hz are recommended)
2. Unbalanced rotor system
Dynamic balancing correction:
Disassemble the impeller for G2.5 dynamic balancing (residual imbalance <1g·mm/kg)
On-site dynamic balancing correction (must meet ISO1940-1 standard)
3. Bearing failure
Replacement standard:
Must replace when radial clearance > 0.15mm
Use laser alignment instrument to ensure that the coaxiality of the motor and the main engine is <0.05mm
III. Pneumatic system processing
1. Pulsation vibration control
Solution:
Install a buffer tank (volume ≥ 10 times the cylinder stroke volume)
Install a Helmholtz resonator (for specific frequency pulsation)
2. Intake valve vibration
Adjustment method:
Check valve stroke (adjustment is required if deviation is greater than 0.5mm)
Replace spring (stiffness coefficient needs to match working pressure)
IV. Electrical system inspection
Motor vibration detection:
Three-phase current imbalance rate <5%
Bearing vibration velocity value <4.5mm/s
Inverter interference:
Dv/dt filter installed at the output end
Carrier frequency adjusted to 8-12kHz range
V. Special case handling
Screw machine rotor wear
Repair process:
Laser cladding repair meshing surface
Re-grind rotor profile (tooth top clearance 0.08-0.15mm)
Perform 3000rpm test vibration detection
Reciprocating machine impact vibration
Handling steps:
Crosshead pin clearance adjustment (0.03-0.05 mm)
Piston rod runout detection (＜0.02mm/m)
VI. Preventive maintenance plan
Daily inspection:
Foundation bolt tightening status
Abnormal noise monitoring
Monthly maintenance:
Vibration spectrum analysis (focus on 2X/3X power frequency components)
Coupling wear inspection
Annual overhaul:
Rotor dynamic balance re-inspection
Bearing lubrication system modification (it is recommended to upgrade to oil-gas lubrication)
Notes
When dealing with vibration, it is necessary to check the pipeline stress simultaneously (it is recommended to use ANSYS stress analysis)
For variable frequency air compressors, the vibration value needs to be tested at 25%/50%/75%/100% load respectively
After vibration treatment, the trend change needs to be monitored for 72 hours continuously
Through the above systematic treatment, the vibration value can usually be reduced by more than 60%. If the vibration persists, it is recommended to use EMA (experimental modal analysis) to accurately locate the fault.