🔍 Key Concepts

• duplex lube oil strainer design and purpose • difference between filtration quality vs continuity of flow • how large propulsion diesels are kept running while maintenance is done

💭 Think About

• Ask yourself what the word duplex suggests about the equipment’s construction and operation. • Think about what problem engineers are trying to avoid in a large main engine if a single lube oil strainer needs to be cleaned. • Consider whether a strainer’s main function is to clean oil more times, clean it more thoroughly in one pass, or allow maintenance without shutting down flow.

✅ Before You Answer

• Verify how a duplex strainer is arranged (two strainers with a changeover valve vs one larger strainer). • Check which option relates to continuous operation during cleaning or maintenance, rather than how fine the filtration is. • Eliminate any choice that implies the oil must pass through the same strainer element twice every time.