What is the main purpose of wear rings in a centrifugal double suction pump?

What is the main purpose of wear rings in a centrifugal double suction pump?

• A. To reduce wear on impeller
• B. To maintain a flow restriction between the impeller discharge and suction areas
• C. To increase pressure
• D. To balance flow

Answer: (B)

Wear rings mainly limit leakage from the high-pressure discharge side back toward the suction side. In a centrifugal double-suction pump, a small clearance exists between the impeller and the casing; liquid tends to sneak from the discharge region into the suction region around the impeller. The wear rings provide a tight, sacrificial sealing surface that maintains this clearance and keeps the flow moving in the intended direction from suction to discharge. Because they are replaceable, they wear instead of the impeller or casing, preserving pump efficiency and head over time. This leakage control is the key to stable flow and better overall performance, which is why this option is the best choice.

Wear rings mainly limit leakage from the high-pressure discharge side back toward the suction side. In a centrifugal double-suction pump, a small clearance exists between the impeller and the casing; liquid tends to sneak from the discharge region into the suction region around the impeller. The wear rings provide a tight, sacrificial sealing surface that maintains this clearance and keeps the flow moving in the intended direction from suction to discharge. Because they are replaceable, they wear instead of the impeller or casing, preserving pump efficiency and head over time. This leakage control is the key to stable flow and better overall performance, which is why this option is the best choice.