Question 73General Subjects - 1st Asst/Chief

The correct answer is A) The rate of evaporation will decrease. The wearing rings of device "7" are typically used to maintain proper clearance between the impeller and casing in a centrifugal pump. As these rings wear over time, the pump's efficiency decreases, resulting in a lower flow rate. Since the evaporation rate in device "23" is dependent on the flow of water to the unit, a lower flow rate from the worn pump will lead to a decreased evaporation rate. The other answer choices are incorrect because: B) Device "7" is likely a centrifugal pump that does use wearing rings; C) The evaporation rate is directly affected by the flow of water, not just the vacuum level; and D) The standby pump labeled "8" is not mentioned as being used in this scenario.