A mechanical seal is a device which helps join systems or mechanisms together by preventing leakage (e.g., in a plumbing

Plumbing

Plumbing is the system of pipes and drains installed in a building for the distribution of potable drinking water and the removal of waterborne wastes, and the skilled trade of working with pipes, tubing and plumbing fixtures in such systems. A plumber is someone who installs or repairs piping...

 system), containing pressure

Pressure

Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

, 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 seal may also be referred to as "packing."

Seal types;

• Induction sealing
  Induction sealing
  Induction sealing, otherwise known as cap sealing, is a non-contact method of heating a metallic disk to hermetically seal the top of plastic and glass containers. This sealing process takes place after the container has been filled and capped.-How it works:...
  
   or cap sealing
• Adhesive, sealant
  Sealant
  A sealant may be viscous material that has little or no flow characteristics and stay where they are applied or thin and runny so as to allow it to penetrate the substrate by means of capillary reaction...
  
  
• Bodok seal
  Bodok seal
  The Bodok seal is a specialised washer that ensures a gas-tight seal between the cylinder yoke or regulator of an anaesthetic machine or any medical device requiring a gas supply, and a gas cylinder...
  
  , a specialized gas sealing washer for medical applications.
• Bridgman seal
  Bridgman seal
  A Bridgman seal, named after Percy Williams Bridgman, seals a high pressure volume by the use of a three part mechanism. A viscous material such as rubber, copper or soap stone is set so that it stretches longitudinally against a hard steel ring, followed by a softer steel ring and horizontally...
  
  , a piston sealing mechanism that creates a high pressure reservoir from a lower pressure source.
• Bung
  Bung
  A bung is truncated cylindrical or conical closure to seal a container, such as a bottle, tube or barrel. Unlike a lid which encloses a container from the outside without displacing the inner volume, a bung is partially inserted inside the container to act as a seal...
  
  
• Coating
  Coating
  Coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...
  
  
• Compression seal fitting
  Compression seal fitting
  A Compression seal fitting, also known as a sealing gland, is intended to seal some type of element when the element must pass through a pressure or environmental boundary...
  
  
• Diaphragm seal
  Diaphragm seal
  A diaphragm seal is a flexible membrane that seals and isolates an enclosure. The flexible nature of this seal allows pressure effects to cross the barrier but not the material being contained....
  
  
• Ferrofluidic seal
  Ferrofluidic seal
  Ferrofluidic is the brand name of a magnetic liquid rotary sealing mechanism made by the Ferrotec Corporation. Magnetic liquid seals are used in rotating equipment to enable rotary motion while maintaining a hermetic seal by means of a physical barrier in the form of a ferrofluid...
  
  
• Gasket
  • Flange gasket
  • O-ring
    O-ring
    An O-ring, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a disc-shaped cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.The O-ring...
    
    
  • O-ring boss seal
    O-ring boss seal
    An O-Ring boss seal is a technique for joining two fluid-carrying pipes, hoses or tubing. In an o-ring boss system, a male threaded part is inserted into a female threaded part, providing a mechanical seal...
    
    
  • Piston ring
    Piston ring
    A piston ring is a split ring that fits into a groove on the outer diameter of a piston in a reciprocating engine such as an internal combustion engine or steam engine.The three main functions of piston rings in reciprocating engines are:...
    
    
• Glass-ceramic-to-metal seals
  Glass-ceramic-to-metal seals
  Glass-to-metal seals have been around for many years, with one of the most common uses being lamp bulb seals. A more recent invention is glass-ceramic-to-metal seals.-Properties:...
  
  
• Hose coupling
  Hose coupling
  A hose coupling is a connector on the end of a hose to connect it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler...
  
  , various types of hose couplings
• Hermetic seal
  Hermetic seal
  A hermetic seal is the quality of being airtight. In common usage, the term often implies being impervious to air or gas. When used technically, it is stated in conjunction with a specific test method and conditions of usage.-Etymology :...
  
  
• Hydrostatic seal
  Hydrostatic seal
  A hydro static seal is a type of mechanical seal. It is a non-contacting seal seals by chocking the flow from one side of the seal to the other. A film is developed between the two sealing surfaces which prevent the two surfaces from touching. They can be used for high speed applications and can...
  
  
• Hydrodynamic seal
  Hydrodynamic seal
  A hydrodynamic seal is a type of mechanical seal. A hydrodynamic seals uses a dynamic rotor with grooves that act as a pump and create an air film that the opposing sealing surface will ride on. A hydrodynamic seal performs better than hydrostatic seals by providing greater film stiffness, lower...
  
  
• Labyrinth seal
  Labyrinth seal
  A labyrinth seal is a type of mechanical seal that provides a tortuous path to help prevent leakage. An example of such a seal is sometimes found within an axle's bearing to help prevent the leakage of the oil lubricating the bearing....
  
   A seal which creates a tortuous path for the liquid to flow through
• Lid (container)
  Lid (container)
  A lid, also known as a cap, is part of a container, and serves as the cover or seal, usually one that completely closes the object.-History:...
  
  
• Rotating face mechanical seal
  Rotating face mechanical seal
  An end face mechanical seal, also referred to as a mechanical face seal but usually simply as a mechanical seal, is a type of seal utilised in rotating equipment, such as pumps, mixers, blowers, and compressors. When a pump operates, the liquid could leak out of the pump between the rotating shaft...
  
  
• Face seal
  Face seal
  A face seal is a seal in which the sealing surfaces are normal to the axis of the seal. Face seals are typically used in static application and are used to prevent leakage in the radial direction with respect to the axis of the seal...
  
  
• Plug
  Plug
  Plug may refer to:* Plug for the plughole in the bathtub, washbasin and sink* Plug , a short lived British comic that ran from 1977 until 1979, when it merged with The Beezer, which featured a character from The Bash Street Kids called Plug as it's main star.* Plug , a family of fishing lures*...
  
  
• Radial shaft seal
  Radial shaft seal
  Radial shaft seals are used to seal rotary elements, such as a shaft or rotating bore. Common examples include strut seals, hydraulic pumps seals, axle seals, power steering seals, and valve stem seals. Early radial shaft seals utilized rawhide as the sealing element, and many elastomeric seal...
  
  
• Trap (plumbing)
  Trap (plumbing)
  In plumbing, a trap is a U-, S-, or J-shaped pipe located below or within a plumbing fixture. An S-shaped trap is also known as the S-bend invented by Alexander Cummings in 1775 but became known as the U-bend following the introduction of the U-shaped trap by Thomas Crapper in 1880. The new U-bend...
  
   (siphon trap)
• Stuffing box
  Stuffing box
  A stuffing box is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements.-Boats:...
  
  , Gland (engineering)
  Gland (engineering)
  A gland is a general type of stuffing box, used to seal a rotating or reciprocating shaft against a fluid. The most common example is in the head of a tap where the gland is usually packed with string which has been soaked in tallow or similar grease...
  
   (mechanical packing)
• Split Mechanical Seal
• Wiper seal
  Wiper seal
  A wiper seal is an axial seal that creates a seal while allowing a reciprocating shaft to pass through the seal's inner bore. Wiper seals are often used for fluid containment and to prevent dirt from entering a reciprocating shaft mechanism....
  
  
• Dry gas seal
  Dry gas seal
  Dry gas seals are non-contacting, dry-running mechanical face seals consist of a mating ring and a primary ring. When operating, grooves in the rotating ring generate a fluid-dynamic force causing the stationary ring to separate and create a gap between the two rings...
  
  
• Exitex seal