Question 46 3AE02 - Third Assistant Engineer (Alt)

The Correct Answer is C. **Explanation for Option C (Bimonthly):** Option C (Bimonthly, meaning every two months or twice a month, but generally interpreted as every two months in maintenance scheduling) is the most appropriate interval for draining the sump of an oiling ring bearing system for impurity removal. 1. **Impurity Accumulation:** While oiling rings continuously feed oil, they also allow heavy impurities (like wear particles, dust, and sludge) to settle in the low point of the sump. 2. **Maintenance Balance:** The maintenance schedule needs to balance the risk of excessive impurity accumulation (which degrades the oil and damages the bearing surfaces) against the cost and disruption of frequent draining. 3. **Industry Standard:** For critical rotating machinery using circulating or settling lubrication systems (like oiling ring bearings), periodic inspection and draining of settled sludge/impurities are standard practice. A two-month (bimonthly) interval provides a sensible balance, ensuring that settled contaminants are removed before they can be thoroughly re-agitated or accumulate to damaging levels, but not so frequently as to waste labor or excessive oil volume. **Explanation of Incorrect Options:** * **A) Every round:** This phrase is vague in this context (not a standard maintenance term related to time) and draining the sump constantly or after every short operational cycle is entirely impractical, unnecessary, and would waste significant amounts of oil. * **B) Daily:** Draining the sump daily is far too frequent for this type of system. Oiling ring systems use a relatively small volume of oil, and contamination takes time to settle. Daily draining would be costly, interrupt operations, and is reserved only for severely contaminated systems or specialized filtration processes, not routine sump cleaning. * **D) Annually:** Draining the sump only once a year is insufficient. Over a 12-month period, contaminants and oxidation products would accumulate excessively in the sump, leading to severe oil degradation, sludge buildup, and increased risk of bearing damage before the scheduled cleanout.