A mechanical seal is a device that helps join systems and mechanisms together by preventing leakage (e.g. in a pumping system), containing

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

, or excluding contamination. The effectiveness of a seal is dependent on adhesion in the case of

sealant Sealant is a substance used to block the passage of fluids through openings in materials, a type of mechanical seal. In building construction ''sealant'' is sometimes synonymous with '' caulking'' and also serve the purposes of blocking dust, so ...

s and compression in the case of

gasket Some seals and gaskets A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...

s. The seals are installed in pumps in a wide range of industries including chemicals, water supply, paper production, food processing and many other applications. A stationary seal may also be referred to as 'packing'. Seal types: *

Induction sealing Induction sealing is the process of bonding thermoplastic materials by induction heating. This involves controlled heating an electrically conducting object (usually aluminum foil) by electromagnetic induction, through heat generated in the object ...

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 Washer most commonly refers to: *Washer (hardware), a thin usually disc-shaped plate with a hole in the middle typically used with a bolt or nut *Washing machine, for cleaning clothes Washer may also refer to: *Dishwasher, a machine for cleani ...

with integral

, 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 A stopper or cork is a cylindrical or conical closure used to seal a container, such as a bottle, tube or barrel. Unlike a lid or bottle cap, which encloses a container from the outside without displacing the inner volume, a bung is partially ...

Compression seal fitting A compression seal fitting, also known as a sealing gland, is intended to seal some type of element ( probe, wire, conductor, pipe, tube, fiber optic cable, etc.) when the element must pass through a pressure or environmental boundary. A compress ...

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. Common uses for diaphragm seals are to protect pres ...

Ferrofluidic seal Ferrofluidic is the brand name of a staged magnetic liquid rotary sealing mechanism made by the Ferrotec Corporation and was first patented by the predecessor company's co-founder R.E.Rosensweig (USP 3,620,584). The seals are used in rotating equi ...

Gasket Some seals and gaskets A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...

Mechanical packing A stuffing box or gland package 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. Components A stuffing box of a sailing boat ...

** Flange gasket **

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 round cross-section, designed to be seated in a groove and compressed during assembly between two or more par ...

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 (abbreviated ORB) system, a male- threaded part is inserted into a female-threaded part, providing a mechanical seal. This system diff ...

Piston ring A piston ring is a metallic split ring that is attached to the outer diameter of a piston in an internal combustion engine or steam engine. The main functions of piston rings in engines are: # Sealing the combustion chamber so that there is min ...

Glass-to-metal seal Glass-to-metal seals are a very important element of the construction of vacuum tubes, electric discharge tubes, incandescent light bulbs, glass encapsulated semiconductor diodes, reed switches, pressure tight glass windows in metal cases, Vacuum I ...

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 ''Glass-ceramics'' are polycrystalline ceramic materials prepared by ...

Heat seal A heat sealer is a machine used to seal products, packaging, and other thermoplastic materials using heat. This can be with uniform thermoplastic monolayers or with materials having several layers, at least one being thermoplastic. Heat sealin ...

Hose coupling A hose coupling is a connector on the end of a hose to connect (or ''couple'') it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler. It is usually made of steel, brass, stainless steel, aluminium or plastic ...

, various types of hose couplings *

Hermetic seal A hermetic seal is any type of sealing that makes a given object airtight (preventing the passage of air, oxygen, or other gases). The term originally applied to airtight glass containers, but as technology advanced it applied to a larger categor ...

Hydrostatic seal A hydrostatic seal is a non-contacting mechanical seal that operates under an equilibrium of forces. Unlike traditional hydrodynamic seals, Hydrostatic seals have two different pressure zones that are used to establish a balanced pressure zone betw ...

Hydrodynamic seal {{Unreferenced, date=June 2019, bot=noref (GreenC bot) 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 ...

Inflatable seal An inflatable seal is a type of rubber seal that inflates and deflates based on the presence of an inflation source. This allows the seal to accommodate a variable sealing gap. When pressure is applied internally to the seal, it inflates to conform ...

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 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 labyr ...

A seal which creates a tortuous path for the liquid to flow through * Lid (container) *

Rotating face mechanical seal An end-face mechanical seal, or a mechanical end-face seal, also referred to as a mechanical face seal but usually simply as a mechanical seal, is a type of seal used in rotating equipment, such as pumps, mixers, blowers, and compressors. When ...

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 applications and are used to prevent leakage in the radial direction with respect to the axis of the seal. Face seals a ...

* Plug *

Radial shaft seal Radial shaft seals, also known as lip seals, are used to seal rotary elements, such as a shaft or rotating bore. Common examples include strut seals, hydraulic pump seals, axle seals, power steering seals, and valve stem seals. Early radial sh ...

Trap (plumbing) In plumbing, a trap is a U-shaped portion of pipe designed to trap liquid or gas to prevent unwanted flow; most notably sewer gases from entering buildings while allowing waste materials to pass through. In oil refineries, traps are used to p ...

(siphon trap) *

Stuffing box A stuffing box or gland package 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. Components A stuffing box of a sailing boat ...

(mechanical packing) * Wiper seal *

Dry gas seal Dry gas seals are non-contacting, dry-running mechanical face seals that consist of a mating (rotating) ring and a primary (stationary) ring. When operating, lifting geometry in the rotating ring generates a fluid-dynamic lifting force causing the s ...

References

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See also

References