Vibration Analysis for Screw Compressors

Collection frequency depends on equipment criticality and operating conditions. Critical screw compressors in continuous service typically require monthly vibration surveys at minimum, with more frequent collection warranted when trending indicates a developing fault. Online monitoring systems provide continuous data for the most critical assets.

Standard practice uses triaxial accelerometers mounted at each bearing housing to capture radial and axial vibration in screw compressors. High-frequency enveloping sensors may be added for early bearing fault detection. Proximity probes are used on equipment with sleeve bearings to measure shaft relative vibration and orbit patterns.

Rotary Screw Compressors fail from rotor bearing wear, oil separator degradation, control faults. Of these, the failures that Vibration Analysis detects earliest are bearing race defects and shaft imbalance — the technique's sweet spot. Lead time on a typical developing fault is 800-1500 hours. That's measured from first detectable signature in the overall velocity per ISO 10816-3, plus envelope spectrum 1-10 kHz to functional failure of the asset.

Duty cycle is the second-biggest interval driver after asset criticality. Rotary Screw Compressors units running near rated capacity 24/7 should follow the tight end of the monthly route work schedule. Equipment cycling on/off through the day generates additional fatigue per operating hour and may need even tighter monitoring. Standby units running occasionally can stretch the interval, but baseline runs are still needed to detect storage-related degradation.