Labyrinth seals and clearance seals are minimum-leakage seals that protect machine elements from contamination through a noncontact method. They operate on the principle of positive clearance and do not rub on shafts or housing.
Labyrinth seal often use a series of noncontact metal rings or other means to form a labyrinth that makes it challenging for unwanted debris to pass through, while keeping necessary lubricants in. Clearance seals are often referred to as floating labyrinth seals. The design of clearance seals have precise control over the clearance between the rotating shaft and the inside diameter of the seal ring. Unlike single lip seals, grooves within labyrinth seals and clearance seals act as individual lips and distribute pressure all across the seal instead of in just one area. Teeth configuration options are available for labyrinth seals and clearance seals including interlocking, stepped, staggered, angles, one piece, split halves, or eight-piece varieties.
There are many different styles of labyrinth seals and clearance seals. Many labyrinth seals are comprised of a rotor (rotating) and stator (stationary) member with a radial gap between the two members. The gap must be larger than the radial clearance of the bearing being sealed. When choosing labyrinth seals and clearance deals, the operating speed and temperature must be considered. These seals generally do not perform well at low operating speeds. Another form of labyrinth seals and clearance seals is a laminar sealing ring, which uses a series of flat metal washer-like rings of varying diameters to create a labyrinth seal.
The design of labyrinth seals and clearance seals reduce friction, maintain low operating temperatures, experience little-to-no wear when maintained, operate at high speeds, and can have a long service life. Labyrinth seals and clearance seals are often available in aluminum, bronze, steel, or plastic materials like PTFE. They are often used in high speed and high temperature applications including in centrifugal compressors and gas turbines.