A petroleum storage depot in Essex providing essential fuel supplies
to various outlets across East Anglia needed some updating of its
condition monitoring system; predictive maintenance system
specialists, Sensonics Ltd were called in to update the facilities
and to retrofit an improved vibration detection system.

When it was commissioned in 1991, the plant's main line pump and motor
station was provided with just one channel of vibration on the pump allowing
only limited fault detection capability. With throughput on the pumps running
at approximately 180m3/hour, any unforeseen breakdown whilst never
representing a danger, could have resulted in a long shut down of the plant,
a complete cut-off of fuel and a very expensive bill.

The station, situated on a hill top site is exposed and open to the elements
and so Sensonics fitted four PZS3 type industrial accelerometers to replace
the existing single channel system. Sensonics PZS3 accelerometers are
of dual case stainless steel construction and being fully welded are sealed
to IP.66/IP.67. and can be installed in minutes allowing for both durability
and ease of installation; the instruments fitted were also ATEX approved
intrinsically safe, suitable for use in hazardous Classified Zone 1 applications.

To provide optimum machine protection, one accelerometer was mounted
on each end of the pump and on each end of the motor, these were
complemented by the existing motor winding temperature measurements.

These latest shear-mode accelerometers with an even broader frequency
band now operate on the site on a 24hour basis often in harsh environmental
conditions. All the Sensonics instruments have a high reliability factor and
contain no moving parts, which makes them virtually maintenance free and
vibration is detected when the accelerometer is shaken back and forth in
its sensitive plain, generating an electrical output proportional to the distress
level in the pump or motor.

Sensonics additionally installed an Aegis Modular Machine Condition
Monitoring System in the site's control room. This comprised of MO9601
single channel vibration modules together with MO9605 single channel
temperature modules, both fitted with A1 (Danger), A2 (Alert) alarms; the
system also incorporated a M09699 display module.

Controls housed in a robust cabinet provide total machinery protection and
prevent costly false alarms or the need for ongoing operator intervention.
A1, A2 level alarms are clearly displayed by red LED's.

The MO9601 vibration module is additionally capable of accepting inputs
from velocity transducers or eddy current probes whilst the MO9605
temperature module will accept inputs from RTD's. Display facilities on
the MO9699 feature a high visibility 3½" digit LED display, a calibration
check facility and remote alarm attenuation.

Fuel to the pumping station is received from a refinery in the Thames
Estuary after being pumped underground over a distance of approximately
57 miles.

The Sensonics system was used in anger within days of the installation:
an alarm shut the plant down after detecting a problem on the drive end of
the motor. Further investigation revealed that a bearing was in need of
lubrication. Had this not have been detected then it is highly probable
that a bearing failure would have occurred. Particularly sobering was the
fact that the old system would not have detected the malfunction and the
plant could have faced shut down for as long as a month.

The Sensonics installation provides a greater level of protection than that
previously in place and a supporting programme to ensure fast spare parts
provision when and if required. Project Engineer for the plant, Alan Black
said "the installation was cost-effective, uncomplicated, straightforward
and completed on time. Both the work and the service provided by
Sensonics were excellent and we were especially impressed when
the system picked up the bearing problem almost immediately. We
had previously used Sensonics equipment more prevalently than any
other supplier throughout our national pipeline network and this early
detection of a fault reaffirmed our confidence in them".

Sensonics manufacture and supply monitoring instrumentation for
predictive maintenance systems on a world-wide basis and are
supported by a network of agents around the world. Full details
are available on

For more information, please contact:-

Sensonics Ltd.
Telephone: +44(0)1442 876833
Fax: +44(0)1442 876477
Web Site:

April 2005

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