Use case 02 · Recurring alarms

A compressor high-vibration alarm that comes back every afternoon

The alarm cleared by itself each evening, and a work order to check the vibration probes found nothing wrong. Valqor compared the alarm times with the process and utility data around the compressor.

Illustrative example based on a common failure pattern
Equipment
K-301 centrifugal compressor, bearing 2
Symptom
High vibration alarm at 7.1 mm/s, nine times in three weeks
Data used
Historian: 11 tags over 3 weeks · Alarm and event log · 4 work orders · Shift logs
01 · The pattern

What the data shows

Bearing vibration rises and falls with the lube oil supply temperature. The daily peak in oil temperature gets higher through the three weeks, and the alarms start once it passes about 52 °C.

K-301 bearing 2 vibration and lube oil supply temperature, 3 weeksBearing vibration (mm/s)Lube oil supply temp (°C)High vibration alarm
2.0366.0481060Sep 22Sep 26Sep 30Oct 4Oct 8Oct 12Alarm 7.1 mm/s

Vibration follows the oil temperature, and the afternoon peaks grow week by week.

02 · The sequence

One afternoon, Oct 3

Historian readings, alarms, operator notes and work orders, lined up on one timeline.

  1. HistorianCooling water supply at 31 °C, up 3 °C on the week before.
  2. HistorianLube oil supply temperature 52 °C, up 6 °C since morning.
  3. HistorianBearing 2 vibration climbs from 4.8 to 6.5 mm/s.
  4. AlarmVI-301B high vibration, 7.1 mm/s.
  5. Operator log“K-301 vib alarm again. Acknowledged, monitoring.”
  6. HistorianOil back to 45 °C and vibration to 4.6 mm/s. Alarm clears.
  7. Work orderWO-5520 “Check K-301 vibration probes.” Probes tested OK.
03 · The causes

Likely causes, tested against the evidence

Each candidate cause is checked against the records, with the evidence for and against it shown side by side.

Lube oil cooler fouling

Supported

Evidence forVibration tracks oil supply temperature hour by hour. The cooler’s water-side temperature rise fell from 8 °C to 4.5 °C over three months.

Evidence againstNo cooler inspection record to confirm fouling yet.

Bearing wear

Possible

Evidence forNight-time baseline vibration is up 0.4 mm/s over three months.

Evidence againstVibration returns to normal each night once the oil cools.

Operation close to surge

Ruled out

Evidence forNone.

Evidence againstAnti-surge margin stayed above 15% during every alarm.

04 · The outcome

Finding and recommended actions

An engineer reviews the finding and the linked records before any action is taken.

The alarms follow lube oil temperature, not load or surge. The cooler is losing capacity, so the oil runs hotter on warm afternoons, bearing clearance changes, and vibration rises with it.

  • Inspect and clean the lube oil cooler at the next maintenance window.
  • Check cooling water flow to the cooler.
  • Take an oil sample to rule out bearing wear before closing the investigation.
More use cases
01 · Recurring trips

A charge pump that keeps tripping on low suction pressure

Six trips in ten weeks, each reset as “no fault found”. The pattern was in the tank level.

See the investigation 03 · Post-maintenance faults

A pump that came back louder after a seal replacement

Vibration more than doubled the day the pump was restarted. The work order had no alignment readings.

See the investigation 04 · Repeat failures

A bad actor pump that keeps eating mechanical seals

Five seals in two years, each lasting less than the one before. The pump was spending more time below minimum flow.

See the investigation

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