Page 50 - ENGINEERING REVIEW NOVEMBER 2022_Neat

ENGINEERING
REVIEW INSIGHT

Diagnosis and Resolution of

Compressor Vibrations and Cooling Fan

Failure in an Industrial Plant

crew compressors form a critical
asset in the process industries,
Swherein most manufacturing
processes are aided by compressed
air. Being a part of the positive
displacement family, the periodic flow
oscillations result in fluctuating dynamic Fig. Failure symptoms in Cooling Fan assembly & parts
forces leading to noise and vibrations
in a screw air compressor. This article are equipped with bell-mouths for the Investigative teardown analysis of
explains an investigation where a efficient and quiet operation of the the stator-rotor rub pattern combined
compressor exhibits high vibrations compressor. In the illustrated case, the with the bearing bore wear pattern
and noise levels leading to failure of the cooling fan failures led to the shutdown hypothesizes conical whirling as a
axial fans in the cooling system, along of the compressor, thereby stalling the possible cause for premature failure.
with a sustainable, robust solution to plant operation. The stator-rotor rub due to excessive
assure uptime and reliability for the dynamic deflection led to insulation
uninterrupted operation of the plant. Prime causes for the Cooling Fan peeling off in the drive end side of the
The screw air compressor under Vibrations and Abnormal Noise motor fan, supporting the hypothesis of
discussion delivers compressed air at There are various reasons for possible the conical whirling of the impeller.
2500m3/h at a pressure of 7bar as malfunctioning of a cooling fan, viz.
per the requirements of the specific wear and tear, excessive system Investigative diagnostics for
industrial application. The motor and resistance, accelerated fouling excessive vibrations in Compressor
the compression element (airend) of coolers from the installation Numerical analysis and experimental
are coupled by a torsional resilient environment, surges in supply voltages, verification
coupling that is dynamically isolated to improper maintenance of coolers, etc. The dynamic characteristics of the fan
minimize the transmission of structural In this case, the cooling fan exhibits subassembly were analysed through a
excitation forces to other subsystems high vibrations and abnormal noises numerical simulation of the complete
of the compressor. The outer rotor resulting from worn-out failure and cooling system and the subassembly of
axial fans in the parallel configuration anomaly in vibration levels. the fan, motor, suspension and support
structure. Experimental verification and
updating of the numerical model were
achieved through an instrumented
impulse generator and piezoelectric
accelerometers mounted on the stator
hub. The fundamental bouncing and
tilting modes were established for
possible excitation from residual
unbalance. Detailed analysis indicates
that the dynamic behaviour of the
subassembly possesses adequate
Fig. a) Illustration of compressor Package b) Cooling system subassembly. design margins for safe operation.

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