Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

18
by Fred R. Szenasi*
Engineering Dynamics incorporated
Vibration and
Noise in
Pumps
Introduction
Although a certain amount of noise is to be expected from centrifugal
pumps and their drivers, unusually high noise levels (in excess of 100
dB) or particularly high frequencies (whine or squeal) can be an early
indicator of potential mechanical failures or vibration problems in centrifugal
pumps. The purpose of this chapter is to concentrate on the
mechanisms that may produce noise as a by-product; however, reduction
of the noise, perse, is not the main concern. The main point of interest of
this chapter is to study the mechanisms and their effect on the reliability
of the pump system. Methods will be presented to reduce the vibration
(and noise) or eliminate the basic causes by modifying the pump or piping
system.
The occurrence of significant noise levels indicates that sufficient energy
exists to be a potential cause of vibrations and possible damage to
the pump or piping. Defining the source and cause of noise is the first
step in determining whether noise is normal or whether problems may
exist. Noise in pumping systems can be generated by the mechanical motion
of pump components and by the liquid motion in the pump and piping
systems. Noise from internal mechanical and liquid sources can be
transmitted to the environment.
Effective diagnosis and treatment of noise sources to control pump
noise require a knowledge of the liquid and mechanical noise-generation
* The author wishes to acknowledge the contributions by the engineering staff of Engineering Dynamics
Inc., who performed many of the analyses and field tests.
422