Question 178General Subjects - 1st Asst/Chief70% to pass
After a disassembly of a single stage centrifugal pump, one finds the outer circumference of the impeller badly pitted and worn. Not having a spare impeller on board, it is decided to turn down the impeller to eliminate the wear/pitting. What will be the pump capacity, in GPM, after the reduction of impeller diameter by 0.5 inches? GIVEN: Original pump capacity = 30 GPM Original impeller diameter = 8 in.
AI Explanation
The correct answer is C) 28.12 GPM.
The reasoning is as follows:
The capacity of a centrifugal pump is directly proportional to the square of the impeller diameter. When the impeller diameter is reduced by 0.5 inches, from 8 inches to 7.5 inches, the new capacity can be calculated as: (7.5/8)^2 * 30 GPM = 28.12 GPM. This is because the pump capacity is reduced in proportion to the square of the impeller diameter reduction.
The other options are incorrect because they do not accurately reflect the impact of the 0.5-inch impeller diameter reduction on the pump capacity.
Related Questions
#176 You suspect a problem with the centrifugal fire pump on your ship, and begin to slowly close the discharge valve. Your suspicion is confirmed when the _______________.#177 The simplest method to use for determining if a centrifugal pump is operating as designed is to _______________.#179 If a centrifugal pump were continually operated with the discharge valve closed the _______________.#180 Which of the following statements is true concerning centrifugal pumps? #181 Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by _______________.