Question 176General Subjects - 1st Asst/Chief70% to pass
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 _______________.
AI Explanation
The correct answer is D) the discharge valve is closed off and there is no change in the discharge pressure.
When the discharge valve of a centrifugal fire pump is closed, the pump is unable to pump any water, so the discharge pressure remains unchanged. This is because the pump is not producing any flow, and the system pressure is determined by the static head, not the pump's output.
The other options are incorrect because:
A) Closing the suction valve would cause the pump to lose its prime and the relief valve would lift.
B) Partially closing the discharge valve would cause the relief valve to lift to maintain the desired discharge pressure.
C) Closing the suction valve would cause the discharge pressure to drop, not the other way around.
Related Questions
#174 When renewing spiral packing in a centrifugal pump stuffing box, after the packing is firmly seated, the packing gland nuts should be _______________.#175 When installing a mechanical shaft seal on a pump, it is important to _______________.#177 The simplest method to use for determining if a centrifugal pump is operating as designed is to _______________.#178 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. #179 If a centrifugal pump were continually operated with the discharge valve closed the _______________.