Centrifugal pumps
| Deviation | Typical causes | Typical consequences | Typical safeguards |
|---|---|---|---|
| No flow (dead head) | Discharge valve closed; control valve fails closed; blockage | Overheating, seal failure, leak | Minimum flow recirculation; low flow alarm or trip |
| Reverse flow | Check valve on stand-by pump passing | Reverse rotation, seal damage, backflow to suction system | Check valves; discharge isolation |
| High discharge pressure | Downstream blockage | Overpressure if shut-off head exceeds design pressure | Design for shut-off head; relief |
| Low suction pressure / level | Upstream level low | Cavitation, dry running, seal failure | Low level trip; low suction pressure alarm |
| Seal leak | Wear, dry running, vibration | Release of flammable or toxic liquid | Dual seals with barrier fluid; seal pot alarm; gas detection; remote isolation |
Gas compressors
| Deviation | Typical causes | Typical consequences | Typical safeguards |
|---|---|---|---|
| Liquid carry-over | Suction scrubber level control failure; slug | Mechanical failure, seal or casing rupture | Scrubber high-high level trip |
| Surge | Low flow, discharge restriction | Vibration, damage | Anti-surge control and valve |
| High discharge temperature | Recycle without cooling, high compression ratio | Seal damage, piping overtemperature | Temperature trip; recycle cooler |
| Reverse flow on trip | Check valve failure | Reverse rotation, gas release | Check valve; blowdown on trip |
| High vibration | Bearing wear, unbalance | Mechanical failure | Machinery protection system (vibration, axial displacement) trips |
| Lube oil low pressure | Pump failure, filter blockage | Bearing failure | Stand-by pump auto start; low-low oil pressure trip |
Written for First Out AI as engineering guidance. It supports engineering work and does not replace it; check every value against your standards, certificates and company rules with a competent functional safety engineer.