🔍 Key Concepts

• Location and purpose of the gravity disk in the fuel oil centrifuge bowl (see the outer edge of the disc stack in the illustration). • How the oil/water interface position moves when the gravity disk inside diameter changes (larger vs smaller ID). • What happens to separated oil flow if the interface is pushed too far toward the sludge/water outlet.

💭 Think About

• In the illustration, trace the path of clean fuel oil and the path of water/sludge. If the fuel is leaving with the sludge, where has the interface moved inside the bowl? • Think about how a larger or smaller gravity disk inside diameter affects centrifugal pressure balance: which change would move the interface outward toward the bowl wall and sludge ports? • Consider whether low back pressure or an incorrect number of disks would normally cause all the fuel to go out with the sludge, or more likely just poor separation/contamination.

✅ Before You Answer

• Verify in the diagram which side of the disc stack is the sludge/water outlet and which is the clean oil outlet. • Mentally shift the interface line: first toward the center, then toward the bowl wall. For each shift, decide whether oil would exit at the oil outlet or at the water/sludge outlet. • Before choosing, rule out options that would more likely cause reduced separation efficiency rather than continuous discharge of all fuel oil with the sludge.