Aux 1 Unit 4

Centrifugal Pumps – Bilge, Ballast

With reference to centrifugal pumps:
(a) explain why it is common practice to start with the discharge valve closed or throttled;(4)
(b) explain why the delivery valve must not be left closed after starting;(3)
(c) state why it is not always necessary to fit a relief valve.(3)

1.Quiz. Study Notes

Answer

A centrifugal bilge pump has not been operating satisfactorily, the air pump was tested and found to be operating correctly.
List FIVE faults that could have caused the problem, stating why EACH fault causes poor operation.(10)

2.Quiz. Study Notes

Answer

With reference to centrifugal pumps used for bilge/ballast purposes:
(a) explain the specific problems which may arise using the pumps for these purposes;(4)
(b) explain TWO methods used to improve pump performance when used for these purposes.(6)

3.Quiz. Study Notes

Answer

With reference to a centrifugal pump/motor set:
(a) state FIVE indications that a fault has occurred;(5)
(b) state a possible cause of EACH fault stated in part (a).(5)

4.Quiz. Study Notes

Answer

(a) Describe, with the aid of sketches, the operating principles of a centrifugal pump.(7)
(b) State why centrifugal pumps are not self-priming.(3)

5.Quiz. Study Notes

Answer

Describe, with the aid of sketch, a system for priming a centrifugal pump using a priming pump driven from the centrifugal pump

6.Quiz. Study Notes

Answer