Seal (mechanical)

Compression seal example

A seal is a device or material that helps join systems, mechanisms, or materials together to contain pressure, prevent leakage of fluid (e.g. in a pumping system), or exclude contamination. The effectiveness of a seal depends on compression in the case of gaskets and adhesion in the case of sealants. Seals are installed in pumps in a wide range of industries including chemicals, water supply, paper production, food processing, and many other applications. ^[1]

A stationary seal may also be referred to as a "packing".

Seal types:

Seals relying on compression

• Closure (container)
  • Crown cork, a.k.a. bottle cap
  • Lid
• Compression fitting
• Compression seal fitting
• Diaphragm seal
• Double seam, the crimped seal used in canning
• End-face mechanical seal
• Face seal
• Gasket or mechanical packing
  • Flange gasket
• Hose coupling
• Inflatable seal, a seal that inflates and deflates in three basic directions of operation: the axial direction, the radial-in direction, and the radial-out direction. Each of these inflation directions has its 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.
• Obturating ring
• Piston ring
• Radial shaft seal
• Stopper (plug), a.k.a. bung or cork
  • Drain plug
  • Laboratory rubber stopper
• Washer
  • 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 ^{[2] [3]}
  • O-ring
  • O-ring boss seal
• Stuffing box (mechanical packing)
• Wiper seal
• Split seal, ^[4] multi-part seals that offer easier installation and maintenance
• Bridgman seal, a piston sealing mechanism that creates a high-pressure reservoir from a lower pressure source

Seals relying on fusion or adhesive bonding

• Glass-ceramic-to-metal seals
• Glass-to-metal seal
• Heat seal
• Hermetic seal
• Induction sealing or cap sealing
• Putty
• Sealant or adhesive
• Soldering and brazing
• Welding

Seals made by liquids blocking gases

• Ferrofluidic seal
• Trap (plumbing) or siphon trap

Non-contact seals

• Dry gas seal
• Hydrodynamic seal
• Hydrostatic seal
• Labyrinth seal, a seal which creates a tortuous path for the escaping gas or liquid

See also

• Joining technology
• Leak

References

1. "GFS Mechanical Seals". Gallagher Seals. Retrieved 5 August 2021.
2. "The Dowty Bonded Seal" (PDF). Archived from the original (PDF) on 22 February 2016. Retrieved 12 August 2016.
3. "Bonded Seals" . Retrieved 12 August 2016.
4. "Information about Split Seals". Mechanical Seals. Retrieved 2023-06-02.