KF 80
The Kracht KF 80 is a gear‑type fuel oil transfer pump that moves heavy fuel oil (HFO) between storage tanks and to the engine after preheating to lower viscosity.
Inspector Detail
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Common issues
- Gear/bushing wear increasing internal clearance and reducing delivered pressure/flow over time
- Shaft seal leakage, particularly as HFO viscosity and temperature change
- Overheating or viscosity lock if HFO is not adequately preheated before pumping
- Relief valve wear or incorrect setting causing over-pressurization or excessive bypass recirculation
- Coupling misalignment
- Abrasive wear from catalytic fines in HFO
- Cavitation from insufficient suction head, especially with cold, viscous fuel
Inspection checklist
- Check shaft seal for leakage
- Verify fuel is adequately preheated to design viscosity before and during pumping
- Check relief valve setting and function
- Monitor discharge pressure and flow against the rated curve - falling performance indicates internal wear
- Inspect coupling alignment
- Check upstream strainer/filter for fouling by catalytic fines or sludge
- Listen/check for cavitation noise at the suction
- Inspect casing for external leaks or corrosion
Service intervals
| Shaft seal inspection | per maker manual, commonly annually or at a set running-hour interval |
| Relief valve function check | annually or per maker schedule |
| Internal clearance/gear wear check | at overhaul, typically every few years, depending on fuel quality and duty |
| Strainer cleaning | condition-based on fouling rate - frequent |
Typical wear limits
| Gear-to-casing radial clearance | wear increases internal slip and reduces delivered flow - overhaul when delivery falls below the required duty rather than at a specific clearance figure, since tolerances vary by pump size - confirm against Kracht's own service data |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Shaft seal kit
- Matched gear set (if supplied as such by the maker)
- Relief valve repair kit
- Coupling element
- Gasket and O-ring set
Safety
- HFO is handled at elevated temperature - burn hazard from hot fuel and a heated pump casing/piping
- Never run this positive-displacement gear pump against a closed discharge without a functioning relief valve - pressure rises rapidly
- Fuel spill/fire risk - contain leaks and eliminate ignition sources in the pump vicinity
- Verify correct isolation/lockout before opening a pump handling hot fuel
Class survey
Fuel oil transfer pumps fall within general machinery survey scope. Where the pump serves an essential fuel transfer duty, class expects a standby/alternative means of transfer and evidence of overpressure protection (relief valve) on the positive-displacement unit.
Components & Design
Component data being added…
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Common failures & inspection points
Service & Maintenance
Gear pump; preheat HFO to reduce viscosity before transfer.
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