The leakage of seal water around the packing on a centrifugal pump is required because it acts as a coolant. Which option best reflects this?

• A. adhesive
• B. scale inhibitor
• C. corrosive inhibitor
• D. coolant

Answer: (D)

The key idea is that seal water around the packing is used to cool and lubricate the packing interface. As the pump shaft spins, friction at the packing generates heat. A small flow of seal water carries away that heat and provides lubrication, reducing wear and preventing overheating of the packing. That’s why the purpose of the seal water leakage is best described as coolant. The other options describe functions that aren’t relevant here—adhesive would imply sticking, scale inhibitor would prevent mineral buildup in water, and corrosive inhibitor would protect against corrosion—none of which explain the cooling role of the seal water.