Full definition
A non-contact sealing device that restricts fluid passage using a series of interlocking grooves, fins, or teeth creating a tortuous (labyrinth) path. Because the seal components never touch, there is zero wear, zero friction, unlimited speed capability, and no need for lubrication — making labyrinth seals ideal for high-speed rotating machinery. Each chamber in the labyrinth path acts as a throttling stage, progressively reducing pressure and velocity. Seal efficiency increases with: more stages (teeth), tighter clearances (0.1-0.5 mm radial), and longer path length. Types: straight-through (axial — simplest, for bearing protection), stepped (axial offset — improved sealing), radial (interlocking teeth — best sealing), and combined. Materials: aluminum, bronze, PEEK, or plastic (soft) against steel (hard) — the soft component is sacrificial if contact occurs during transients. Applications: bearing housings (the most common use — prevents grease loss and contaminant ingress), turbomachinery (gas turbine seals), compressors, steam turbines, and high-speed spindles. Labyrinth seals do not provide hermetic sealing — they minimize leakage to acceptable levels. For bearing protection, they are often combined with a felt or lip seal for secondary protection. Per API 610 (pumps), API 617 (compressors), and OEM specifications.