ONLINE & OFFLINE VIBRATION SOLUTIONS
Vibration monitoring is just like checking the pulse of the patient. Now
two methods can be adopted based on the condition of the patient. One can be a
periodic scanning of the pulse & other can be continuous pulse monitoring
in ICU. Similarly for the machines which lie in less critical zone, periodic
vibration scanning system is advisable. Machine which are critical with respect
of safety, environment & directly affect the production, online vibration
monitoring systems are advocated. Following is the broad criterion for
implementation of different technologies-
1. Online
System: This system holds well for critical category of assets which have
immediate impact on safety, environment & production for example turbines,
compressors, critical pumps & blowers etc.
2. Offline
System: Less critical or semi critical assets are good targets for
portable/offline technology. On these assets periodic scanning is good enough
to judge the present condition.
ONLINE VIBRATION MONITORING: These are continuous
vibration monitoring systems employed on critical rotating assets like turbines,
critical compressors, blowers, pumps etc. Sensor & system selection depends
on many factors like machine type, type of bearings, machine speed, machine
components, machine elements etc. These types of systems act as protection
safeguard against excessive vibration & also do the condition monitoring
job if the analysis software & module has been included in the system. As
far as turbines are concerned where bearing of interest is fluid film (journal),
Bently Nevada System is one of the best systems that I have worked on. Bently
system is really good in rotor dynamics due to its long experience in this field.
On rolling element bearings SKF has deep understanding and does a really good
diagnostic on them. CSI is also good solution in this area.
PORTABLE VIBRATION MONITORING SOLUTION: As already
discussed portable or vibration scanning solution is good for less critical
assets. These are the assets which can be periodically scanned or can be
scanned when there is some unusual indication regarding performance of the
machine. Normally amplitude monitoring & FFT analysis is done on these kind
of assets. Other techniques like phase analysis & orbit analysis may also
be employed where we have facility to tap the signal through BNC port. Again
SKF & CSI are very good in this area. Bently Nevada Snapshot & ADRE are
also useful tools. Recently some new players in the condition monitoring field
like Fluke have also introduced some exciting solution in the offline vibration
segment. They have introduced two models that I have used till now. One of them
is FFT based vibration analyser with auto fault diagnostic & auto advisory
feature. This is a good tool for the shop floor engineers / technicians who have
limited knowledge of vibration. The system is easy to use & interpret the
faults.
Disclaimer: The discussed solutions are based on my
own experience & are my personal views.