Vibration analysis of oil-injected twin-screw compressors using simple simulated waveforms

Abstract

There are few published references on the practical diagnosis of oil-injected twin-screw compressors. In most cases of diagnosis on this type of compressors, usual methods that deal with machine elements, gears, rotational parts, rolling element bearings, couplings, and so on, are employed. These methods are certainly effective but not specified for diagnosis of oil-injected twin-screw compressors. The purpose of this study is to develop an effective tool for diagnosis of vibrations in oil-injected twin-screw compressors. Vibrations in this type of compressors vary with the quality of machining and operating conditions. Therefore, it is difficult to establish a systematic method of analysing vibration data in all practical conditions. This paper reports on a method developed to diagnose lobe meshing vibrations on this type of compressors using synthesized waveform models. Typical vibration waveforms are synthesized from basic waves with measured data and simple assumptions. These synthesized waveforms are then used to diagnose lobe mesh and resonance vibration problems in the compressors, after being modulated into modified waveform models. Waveforms synthesized by this method were fairly in good agreement with measured waveforms, indicating that this method is an effective tool in diagnosing lobe mesh vibration problems. There is no verified method or information on the diagnosis of lobe mesh vibrations in oil-injected screw compressors; this method, therefore, offers a effective analysis.