Test examples 10
Class 1
1. Describe a centrifugal oil purifier and explain in detail how separation occurs. Should a purifier be worked at its rated capacity if the maximum efficiency of separation is desired?
2. Sketch and describe a purifier and explain how the separation of dirt and water from oil is accomplished. What factors increase the speed and efficiency of the separation? Comment on the advantages and disadvantages of water washing lubricating oils.
3. Discuss the effects of water in lubricating oils and fuel oils. Explain how the presence of water can be detected and explain how water can be separated from oil by virtue of their different densities.
4. Sketch and describe three types of lubricating oil filters used aboard ship. Give reasons for using different types and relative positions in the system.
5. Explain the necessity for regular laboratory analysis of lubricating oils and the importance of obtaining a truly representative sample for this purpose. Without specialist equipment explain how to test for the following:
a. Sludge
b. Water
c. Acidity
State what effect each of these has on bearing and how it is countered.
Class 2
1. Sketch a self-cleaning filter and describe its operation. Explain the function of magnetic filters. State why magnetic filters frequently complement self-cleaning filters in lubricating oil systems and why centrifuges do not render static filters redundant.
2. With reference to centrifugal separators answer the following:
a. Differentiate between the purpose and operation of purifiers and clarifiers.
b. Explain how these different roles are achieved.
c. Describe with sketches a self-cleaning arrangement.