Question 114Steam Plants - QMED

The correct answer is B) maintain oil supply for several minutes to bearings should the lube oil service pump fail. The gravity tank in a gravity lube oil system is designed to provide a positive suction head to the lube oil service pump in case the pump fails. This ensures that the bearings and other critical components continue to receive lubrication for a short period, even if the primary lube oil pump stops functioning. This temporary oil supply allows the crew to address the pump failure and restore normal operation, preventing damage to the machinery. The other options are incorrect because the gravity tank does not primarily serve to supply the pump with positive suction (A), store heated oil (C), or settle the oil for purification (D). These are not the primary functions of the gravity tank in a gravity lube oil system.