Alfa Laval MAB-205-MDO-Purifier
Alfa Laval MAB-205-MDO-Purifier gear-driven solids-retaining separator for auxiliary fuel/lube separator, optimised for marine diesel oil purification. Fuel oil capacity 3449 l/h, lube oil capacity 2760 l/h. Bowl diameter 340 mm, motor power 5.5 kW. MAB is the legacy gear-driven separator widely used on older fleets and gensets.
Inspector Detail
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Common issues
- Bowl disc stack fouling/sludge buildup reducing separation efficiency
- Gravity disc or water transducer mismatched to the feed oil density, causing loss of interface control
- Friction clutch/gearbox wear reducing bowl spin-up performance or causing vibration
- Seal ring or O-ring degradation causing sludge/oil leakage at the bowl
- Excessive vibration from bowl imbalance due to uneven sludge buildup or worn bearings
- Sludge discharge valve/piston not sealing correctly, causing continuous or incomplete discharge
- Feed pump or preheater malfunction leading to incorrect feed temperature/viscosity at the bowl
Inspection checklist
- Check the bowl disc stack and sludge space for buildup at each scheduled opening
- Inspect and check the bowl body and lock ring for corrosion, cracks or wear - a safety-critical rotating pressure part
- Check friction clutch pads/discs for wear against the maker's tolerance
- Verify the sludge discharge cycle opens and closes fully; inspect discharge slide/piston seals
- Check gear and pinion condition and gearbox oil level/condition
- Verify vibration levels against baseline/maker's limit while running
- Inspect feed/preheater temperature control and confirm correct operating temperature for the oil grade
- Check bowl spindle bearing condition and lubrication
Service intervals
| Bowl disc stack cleaning | per fouling trend or the maker's schedule, typically every 500-1000 running hours |
| Bowl overhaul (seals, O-rings) | annually or per the maker's manual |
| Gearbox oil change | per the maker's manual, typically every 2000-4000 hours or annually |
| Friction clutch inspection | per the maker's schedule, typically annually |
| Bowl body/lock ring mandatory inspection | per Alfa Laval's mandatory bowl inspection interval - safety critical, do not extend |
Typical wear limits
| Bowl lock ring/body corrosion or wear | condemn per Alfa Laval's mandatory bowl inspection criteria - safety-critical, follow the maker's own limits rather than a generic figure |
| Friction clutch pad wear | replace per the maker's minimum thickness - confirm against the separator's own manual |
| Gear/pinion tooth wear | replace per the maker's tolerance - confirm against the separator's own manual |
Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.
Critical spares
- Bowl seal/O-ring kit
- Disc stack or individual discs
- Friction clutch pads
- Sludge discharge valve seals
- Gearbox bearings/seals
Safety
- The bowl is a high-speed rotating pressure component - never exceed the maker's mandatory overhaul/inspection interval for the bowl body and lock ring, as failure can be catastrophic
- Hot oil and steam from the heater present a scald risk
- Rotating clutch/gearbox entanglement hazard
- Follow the maker's lock ring tightening and bowl assembly procedure exactly - incorrect assembly is a known cause of bowl disintegration incidents
Class survey
Fuel oil purifiers are typically checked at survey for effective separation performance and sludge discharge operation, and for current status of the maker's mandatory bowl overhaul/inspection programme; class may ask for records showing the bowl was overhauled within the manufacturer's required interval.
Components & Design
Component data being added…
Technical Data
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Common failures & inspection points
Paring disc, top disc, mud ports check for dull spots/wash-out; erosion depth >0.2 mm (bowl/cap) or >0.5 mm (other) = replacement.
Leaks at cover/bolted joints/mud outlet; gasket rings (EPDM) change every 6000–8000 h, original parts only.
Check vibration/noise; bearings change in pairs every 12000–16000 h, lubricate correctly; do not increase throughput during vibration.
Belts every 3000 h (tension per manufacturer), cracks/wear; coupling check for axial play (>0.5 mm = fault), corrosion.
Monitor current consumption nominal/actual; clean bowl during shutdown; check pre-filtration + lubrication; limit sludge volume.
Type-general inspection and maintenance points for this equipment category — not model-specific.
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