Screw Compressor High Pass Frequency Vibration
High vibration levels in a screw compressor after overhaul were traced to oil injection restriction, mechanical valve issues, and missing filtration components. Correcting these problems reduced vibration to 2 mm/s.
Case Study: High Pass Frequency Vibration in Screw Compressor After Overhaul. By Using Vibration + Ultrasound + RDI Motion Amplification .
I recently supported a customer facing high vibration levels on a screw compressor after a major overhaul. The issue appeared at the rotor pass frequency of 240 Hz with a significant amplitude of 20 mm/s RMS.
The compressor had been overhauled due to worn male and female screw rotors. The vibration spectrum showed a dominant peak at 240 Hz, typically associated with rotor related issues.
It conducted a detailed two-day diagnostic investigation, combining advanced vibration analysis with system inspection. Here's what we found:
Root Cause Identified:
1-Oil injection restriction at both inlet and discharge sides
2-Passing mechanical valves, leading to pressure and flow inconsistencies
3- Missing filtration components during reassembly, which exacerbated the issue.
Once these issues were corrected, the compressor's vibration levels significantly improved to 2 mm/s , restoring stable and reliable operation.
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