🔍 Key Concepts

• Typical clearance limits for pump wearing rings in low pressure centrifugal pumps • How excessive clearance affects pump efficiency, capacity, and NPSH (net positive suction head) • Standard maintenance options when clearances are slightly above, at, or within acceptable tolerances

💭 Think About

• Compare the measured clearance (0.011"–0.013") with what you know or can infer about normal design clearances for low pressure pump wearing rings. • Think about what happens to pump performance if you increase clearance slightly versus a lot—does this measurement suggest a critical problem or something still serviceable? • For each option, ask: Is this action proportional to the amount of wear indicated by the measurement, or is it more appropriate for severe damage/out-of-tolerance wear?

✅ Before You Answer

• Verify whether 0.011"–0.013" is typically considered within, near, or outside the recommended clearance range for this type of pump. • Check which options (replacement, machining, oversized parts, or doing nothing) are usually reserved for clearances well beyond allowable limits. • Confirm that the chosen option matches reasonable preventive maintenance for a pump that is otherwise serviceable and only slightly worn.