Two workhorses of the engine room
The ALFA LAVAL PA605 and the MITSUBISHI SJ series are both disc-stack centrifugal separators used for fuel and lube oil on board. The operating principle is similar, but wear parts differ in dimension, material and fitting method. Mixing them causes vibration, oil carry-over or poor separation.
Common wear parts
- Seals and O-rings — oil and heat resistant grades; replace as a set, not one at a time.
- Disc stack — replace the set when distorted, scored or heavily coked.
- Spindle bearings — the main source of vibration and noise; replace preventively by hours.
- Distributor and paring disc — scale in water passages affects sludge discharge.
- Friction pads and brake parts — affect start and stop times.
- Small items — inlet pipes, outlet nozzles; low cost but a missing one stops the machine.
Selecting parts for the PA605
- Confirm whether the unit is an early or later generation; some sub-assemblies are not interchangeable within the same model name.
- Choose original or equivalent seal material; low-cost rubber ages quickly in hot fuel.
- When replacing the disc stack, inspect the spindle taper and lock nut at the same time.
Selecting parts for the MITSUBISHI SJ series
- There are many suffixes in the SJ range — always supply the nameplate photo and serial number.
- Water-side parts such as the distributor scale up easily; stock them together with seals.
- Equivalent new parts are widely used; confirm material grade and dynamic balance report.
What to send with an enquiry
- Nameplate photo showing model, serial number and year of manufacture.
- Photos of the parts to be replaced, especially the failed item.
- Vessel schedule and replacement window, which decides whether air freight is needed.
With separator parts, buying the right item once matters more than buying quickly. For PA605 and MITSUBISHI SJ series separator parts, see Marine Equipment or contact us with nameplate and part photos.