Class 4 (4th Engineer) MEKG 📅 Dec 2025

Exam Question

(a) What is meant by the term 'purification' and what does it 'separate'? (3)

(b) What are the basic methods of 'separation'? Explain the functioning of 'purifier' and 'clarifier'? (3)

(d) What is 'NOMOGRAM' and how is the correct 'gravity disc' size selected? (6)

Reference Answer

### (a) Definition of Purification and Separation
**Purification** is a mechanical process employing centrifugal force to separate substances from a liquid medium. Onboard marine vessels, this primarily applies to the treatment of fuel oil and lubricating oil prior to their use in machinery.
The objectives of purification are threefold:
1. **Solid-Liquid Separation:** To remove solid impurities from a liquid. These solids include sand, rust, scale, catalytic fines (cat-fines like Al₂O₃ and SiO₂), asphaltenic sludge, and other particulate matter. Failure to remove these results in abrasive wear of fuel pumps, injectors, piston rings, and liners.

Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.

View plans Browse library

← Browse more questions

Prepare on Android — MeoMock on Google Play