🔍 Key Concepts

• Study where port D is located relative to the disc stack and bowl wall in the purifier. • Think about the normal flow path of light phase (oil) and heavy phase/water and sludge inside a self‑cleaning centrifugal purifier. • Recall where dosing/closing water connections are usually found (near the top operating water system) versus where separated products discharge.

💭 Think About

• Trace the flow: from the feed inlet, where do the lighter and heavier liquids move under centrifugal force, and where would they be collected and discharged? • Look closely at what region of separated material is immediately inside port D in the cross‑section: does it look like clear liquid, heavier liquid, or solid sludge? • Ask yourself whether dosing or closing water would normally exit through a mid‑bowl side port, or through piping associated with the operating-water block at the top of the machine.

✅ Before You Answer

• Verify which color/shading around D corresponds to the light phase pathway and which corresponds to the heavier material near the outer bowl wall. • Confirm whether accumulated sludge is shown as a distinct, thick layer at the very outer radius, or if D is slightly inboard from that layer in a liquid region. • Make sure you recognize that dosing/closing water are part of the operating water control system, usually connected to the upper water block, not to the side of the bowl where separated product leaves.