Which seal type is commonly used to prevent oil leakage in the turbine lubrication system?

• A. O-ring seal
• B. Lip seal
• C. Labyrinth seal
• D. Gasket seal

Answer: (C)

Preventing oil leakage along a rotating shaft in a turbine lubrication system calls for a seal that resists leakage without relying on constant contact. A labyrinth seal achieves exactly that: it provides a long, winding, non-contact path around the shaft. Oil trying to escape must navigate multiple turns and narrow gaps, which creates several pressure drops and impedes flow. The result is a high resistance to leakage while avoiding wear from touching surfaces, so it can handle the high speeds and temperatures typical of turbine lubrication systems.

Because the seal doesn’t rely on continuous contact, there’s minimal wear and a longer life under demanding operating conditions. It also tolerates shaft runout and vibration better than a traditional contact seal. In contrast, O-ring and lip seals depend on tight, moving contact to seal, which leads to wear and potential leakage at high speeds or pressures, while gaskets are static and not suitable for sealing around a rotating shaft.