Seal (mechanical)


A mechanical seal is a device that helps join systems or mechanisms together by preventing leakage (e.g. in a pumping system), containing pressure, or excluding contamination. The effectiveness of a seal is dependent on adhesion in the case of sealants and compression in the case of gaskets.


A stationary seal may also be referred to as 'packing'.


Compression seal example


Seal types:


  • Induction sealing or cap sealing
  • Adhesive, sealant
  • Bodok seal, a specialized gas sealing washer for medical applications
  • Bonded seal, also known as Dowty seal or Dowty washer. A type of washer with integral gasket, widely used to provide a seal at the entry point of a screw or bolt
  • Bridgman seal, a piston sealing mechanism that creates a high pressure reservoir from a lower pressure source
  • Bung
  • Compression seal fitting
  • Diaphragm seal
  • Ferrofluidic seal
  • Gasket or Mechanical packing
    • Flange gasket
    • O-ring
    • O-ring boss seal
    • Piston ring
  • Glass-to-metal seal
  • Glass-ceramic-to-metal seals
  • Heat seal
  • Hose coupling, various types of hose couplings
  • Hermetic seal
  • Hydrostatic seal
  • Hydrodynamic seal
  • Inflatable seal Seals that inflate and deflate in three basic directions of operation: the axial direction, the radial-in direction, and the radial-out direction. Each of these inflation directions has their own set of performance parameters for measurements such as the height of inflation and the center-line bend radius that the seal can negotiate. Inflatable seals can be used for numerous applications with difficult sealing issues.
  • Labyrinth seal A seal which creates a tortuous path for the liquid to flow through
  • Lid (container)
  • Rotating face mechanical seal
  • Face seal
  • Plug
  • Radial shaft seal
  • Trap (plumbing) (siphon trap)
  • Stuffing box (mechanical packing)
  • Wiper seal
  • Dry gas seal