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Unbalance Detection Prevents Pump Room Fan Breakdown on VLCC Tanker

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Unbalance Detection Prevents Pump Room Fan Breakdown on VLCC Tanker
Days to Resolution
0
Cost Avoidance
$ 0
Downtime Saved
0 Hours
Max Threshold Breach
0 %
  • Incident Overview

Vessel Type

VLCC Tanker Vessel

Detection Date

27 March 2023

Equipment

Pump Room Fan No. 1

Sensors

USB powered MEMS triaxial AdViSe sensor

Detection Method

AdViSe Handheld device

Measurement Frequency

1 measurement every 3 months
It was late March 2023 when routine vibration checks were carried out on a VLCC tanker using the AdViSe Handheld system. Pump Room Fan No.1 appeared to be in normal operation, with no visible signs of malfunction. However, the data revealed something different: elevated RMS velocity and a strong first-order harmonic indicated a developing unbalance on the fan impeller. The system flagged the issue as “Unacceptable” prompting an inspection that confirmed the damage. The bearings were replaced during scheduled maintenance, avoiding an estimated $5,920 in additional costs and preventing more severe damage to the system.
  • Problem Identification

Detected Symptom

Elevated RMS velocity and Peak-value of 1st order harmonic.

Fault Type

Fan Impeller Unbalance

Signal Characteristics

  1. 01.
    RMS velocity 27% above threshold value (Mar 27, 2023)

  2. 02.
    Amplification of 1st order harmonic in frequency spectrum

  • Actions & Corrective Measures

Action Taken

Overhaul maintenance and impeller replacement

Repair Date

3 April 2023

Post-Repair Status

Vibration Levels Post-Repair: “Fair” due to minor couple unbalance between motor and fan impeller. Future trending was recommended by AdViSe algorithm.
  • Conclusions
  1. 01.
    Fault detection prevented system total failure, extended damages and downtime.

  2. 02.
    AdViSe Handheld system accurately identified and classified the issue, allowing planned maintenance.

  3. 03.
    Diagnostic method based on spectrum analysis proved effective in real ship conditions.

  4. 04.
    Estimated cost avoidance: $5920

Analysis Process

2023-03-27
Initial Deviation Detection
AdViSe Handheld system detected elevated RMS velocity (27% above threshold) and automatically flagged as "Unacceptable".
2023-03-27
2023-04-03
Corrective Action Completed
Overhaul maintenance and impeller replacement completed. System returned to normal operation with 'Fair' vibration levels due to to minor couple unbalance between motor and fan impeller.
2023-04-03
Future Trending
Future trending was recommended by AdViSe algorithm.
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