USCG Exam PracticeLube oil and fuel oil systems
When a centrifuge is operated as a purifier rather than a clarifier, what additional step is required before admitting oil to the bowl?
- A. The bowl must be pre-spun at half speed to seat the disc stack
- ✓ The bowl must be primed with fresh water to establish a liquid sealCorrect
- C. The gravity ring must be removed to allow free water to pass through
- D. The throughput rate must be increased to maximum to generate sufficient centrifugal force
Why B is correct
NAVEDTRA 14075 §3-4 specifies that a centrifuge run as a purifier needs a liquid seal (a 'water dam') established by priming with fresh water before oil is admitted. A clarifier, which removes only solids, uses no water seal.
Cited:NAVEDTRA 14075 §3-4