What is the purpose of seal water in a centrifugal pump?

The purpose of seal water in a centrifugal pump is to lubricate and cool the packing. When the pump operates, the pump shafts rotate, and seals are required to prevent the leakage of the pumped fluid. Seal water helps maintain the integrity of these seals by providing both lubrication and cooling. It ensures that the packing material does not overheat due to the friction generated during operation. Adequate lubrication extends the life of the packing and maintains the efficiency of the pump, preventing leakage that can lead to a loss of volume and pressure in the system.

Other options might suggest functions like increasing pressure or flushing impurities, but those don't accurately capture the primary role of seal water. Its key function is to protect and enhance the performance of the sealing system, which is critical for the reliable operation of the pump.