🔍 Key Concepts

• Purpose of gravity lube oil tanks in turbine systems (emergency / standby supply to bearings) • Normal flow path of oil from gravity tank during operation and during pump failure • How overflow and return lines are usually routed in closed lube oil systems

💭 Think About

• Ask yourself: In a loss of lube oil pump pressure, what role does the gravity tank play for the turbine bearings? • Think about where gravity-fed oil needs to go FIRST to protect the bearings: directly to bearings, back to the sump, or into a pump suction? • Consider which statement describes a normal, safe design feature versus something that would risk losing gravity head or flooding the sump.

✅ Before You Answer

• Verify how a gravity tank is connected in a typical turbine lube oil system schematic (to bearings, to sump, to pump suction, or all three). • Check whether an overflow from a tank that is providing emergency head would be led straight back to the sump or managed another way. • Confirm which option best reflects a safety feature that ensures continuous lubrication if the pump stops.