🔍 Key Concepts

• Centrifugal oil purifier operation (what it separates and how) • Difference between contaminants and useful fuel components • Relative density/specific gravity of solids, water, and fuel oil

💭 Think About

• Ask yourself: In fuel treatment, what is the purifier supposed to REMOVE, and what is it supposed to KEEP? • Which listed substances would normally be considered the fuel itself rather than an impurity? • Among the choices, which one is clearly a solid contaminant that can be spun out by centrifugal force?

✅ Before You Answer

• Identify which options are actual fuels or lubricants (things you want to keep, not remove). • Identify which option is a solid normally present in dirty fuel oil that should be removed by purification. • Recall that a centrifugal purifier mainly separates based on difference in density between fuel, water, and solids.