Acoustic and Vibration Analysis of Fluid Induced Blower and Piping Unwanted Motion

This paper presents investigational findings and a discussion of recommendations relating to sound and vibration measurements performed in connection with a fluid induced vibration issue on two air blowers and attached exhaust piping at an industrial facility. These vibration and sound measurements were prompted by recent check valve failures for the air blower units, and unacceptable sound levels emanating from these units and affecting nearby residents. This data was acquired during steady state operating conditions of the blowers under normal operating conditions. An FFT data acquisition system, a piezoelectric microphone and three piezoelectric triaxial accelerometers were used to collect vibration measurements at each of the 70 locations on the blowers, motors, blower bases, and exhaust piping, while sound measurements were simultaneously acquired with the microphone. Piping and blower vibration readings were used to construct an operating deflection shape analysis of the blowers, foundations and attached piping system. The resulting vibration and sound analysis revealed that acoustic excitation of the piping system appeared to be the likely source of the high vibration, high sound pressure levels; piping cracks and check valve failures. Corrective actions were implemented that reduced the sound pressure levels, vibration levels, and reduced/eliminate the piping damage and valve failures.