The vibration monitoring
system shall include key phasors, axial position transducers, vibration
transducers, signal conditioning, necessary cable and junction boxes, monitor
and provision for remote output signals. Vibration Sensors and mounting
hardware material shall be minimum 316 SS. Aluminum material shall not be used
for instrumentation.
For rotating equipment
operated at speeds below 6,000 RPM the external measuring type vibration
detector or transmitter shall be selected. For operating speeds of 6,000 RPM
and above the shaft measuring type detector or transmitter is preferred.
However, if the installation of shaft measuring type detector is not feasible,
the external measuring type vibration detector may be used with prior approval
by Company.
External measuring type of
vibration detector or transmitter shall be magnetic velocity type. Proximity
probes shall be selected for centrifugal gas compressor radial bearing
vibrations (X&Y suction and discharge), thrust bearing axial movement (2
Z-direction channels).
Accelerometers shall be used for detection of vibration
on the gas producer, power turbine and accessory drive unit. The signals from these components shall be
integrated to velocity in the monitor unit and displayed as velocity levels.
Local mounted vibration switches shall be used for
detection of vibration on lube oil and process cooler fans. A minimum of one (1) switch is required on
each fan. The switches shall be manual local reset type.
Detector / Transmitter shall be powered by 24 VDC.
Output shall be 4 – 20 mA, 3 wires. Each direction of vibration sensor shall
have the individual pair output cable. Enclosure housing shall be approved for
explosion proof Class I, Div 1, Group D Hazardous Area.
Sensors and controls for measuring
vibration of rotating equipment shall be provided as specified in the project
equipment specifications and data sheets. Vibration sensors monitoring /
shutdown system shall be provided with a starting time delay to prevent
shutdown of equipment during start-up. Delay period shall be in accordance with
the recommendation of the rotating equipment Manufacturer. The external
measuring type detector or transmitter shall be mounted on a vertical surface
in order to respond to the horizontal component of vibration.
The monitoring systems shall be integrated with the unit
control panel. Readings shall be expressed in micrometers for amplitude and
axial position. Acceleration signals shall be integrated to read velocity in
mm/s rms. Alarm indications shall be latched type. All indication and alarms
displayed on the vibration monitoring system shall be capable of display on DCS
via a serial communication link. The monitoring instrumentation shall conform
to API 670 “Non contacting Vibration and Axial Position
Monitoring Systems” as appropriate. Vibration monitoring device shall
have a LCD display screen which shall be
capable of performing bar graph graphics.
Vibration Monitoring shall be mounted on the respective
rotating equipment’s PLC cabinet. Each
vibration sensor shall be treated as a separate sensing circuit with individual
monitoring display.
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