🔍 Key Concepts

• Fuel oil vs. lube oil systems and what each typically requires before use • How centrifugal separators/purifiers work and the ways liquid is moved inside them • The difference between filtration (straining) and purification (separating different liquids/solids by density)

💭 Think About

• Which process would logically need different ways of moving or distributing the liquid inside a separator—shaking, circulating, or spraying? • Do you usually hear "shaker" and "spray" associated with strainers/filters, or with centrifugal separators and tanks? • Think about which system most needs water and sludge removed from oil before use: fuel oil, lube oil filtration, lube oil purification, or piston cooling?

✅ Before You Answer

• Be clear on the difference between filtration (using a screen/element) and purification (using centrifugal force to separate phases). • Ask yourself which of the four choices commonly uses centrifuges/separators on board ships. • Verify which system’s standard textbooks or manuals describe shaker, circulation, and spray as methods.