Which statement correctly identifies a difference between labyrinth and carbon seals?

• A. Labyrinth Seals Are Contact Seals; Carbon Seals Are Non-Contact
• B. Labyrinth Seals Use Carbon Faces; Carbon Seals Use Metal Faces
• C. Labyrinth Seals Are Non-Contact; Carbon Seals Provide A Dynamic Carbon-Face Seal
• D. Labyrinth Seals Require Lubrication To Function

Answer: (C)

Labyrinth seals and carbon seals differ mainly in whether the seal relies on non-contact flow barriers or on a contact between seal faces. Labyrinth seals are non-contact devices; they use a long, tortuous path formed by teeth or grooves to impede leakage without any rubbing of seal faces. This design minimizes wear and can tolerate harsh environments since there’s no metal-to-carbon contact at the sealing interface. Carbon seals, on the other hand, use carbon seal faces that ride against a mating surface, forming a dynamic seal with controlled contact and a thin lubricant film. This face-to-face interaction is what actually seals, and it requires proper lubrication and precise clearance control to manage wear.

That’s why the statement capturing the difference is that labyrinth seals are non-contact, while carbon seals provide a dynamic carbon-face seal. The other options mix up the materials or imply lubrication requirements that don’t define the fundamental difference.