If the wearing rings of device "7" shown in the illustration become worn, how will the evaporation rate in "23" be affected? Illustration MO-0111

Correct Answer: Option A — The rate of evaporation will decrease.

Device 7 is the feed pump. Worn wearing rings increase internal recirculation within the pump, reducing its volumetric efficiency and discharge pressure. Since the evaporation rate is directly dependent on the volume of feed water supplied to the unit, a decrease in pump output results in a lower evaporation rate.