Industrial seal self study guide - SKF.com

Glossary of Seal Terms
Abrasives – Materials that cause wear,
friction or irritation
All-Rubber Seals – A non-metal clad seal made of
rubber commonly used where space limitation and
installation difficulties are a major consideration.
Two basic types of HS all-rubber seals are solid
and split, both require a cover plate for proper
compression and sealing.
Auxiliary Lip – See Secondary Lip
Axial Seal – Applies force along the direction of
the shaft, usually between one moving and one
stationary element. Examples: carbon
face seal, V-Ring.
Axial Clamp Split Seal – Made of nitrile, these
compact seals operate against a rotating step or roll
face. Recommended for large diameter applications
where there is the need for a second seal to
exclude dirt.
Bearing – An anti-friction device that supports,
guides, and reduces friction between fixed and
moving machine parts. Rolling bearings rely on
balls or roller elements riding within raceways on
a thin film of lubricant. Plane or sleeve bearings
use only a lubricant film.
Bi-rotational Seal – A rotary shaft seal which will
seal fluid regardless of direction of shaft rotation.
Bond – The adhesion established by vulcanization
between two cured elastomer surfaces, or between
one cured elastomer surface and one
non-elastomer surface.
Bonded Seal – Design feature of a type of radial
lip seal. The heel of the sealing element is attached
(bonded) to the seal case by an adhesive during the
molding operation.
Bore – See Seal Bore.
Bore-tite – A sealant that fills small bore
imperfections.
Bottom Out – Installation of a seal into a groove
until it reaches the end of possible travel. Additional
force should not be used or damage can result.
Buna-N – See nitrile.
Burr – A rough edge on metal or other material
after it has been cast, cut, or drilled.
Case, Bonded – A design feature of a type of radial
lip seal wherein the heel of the sealing element is
attached to the seal case by an adhesive during the
molding operation.
Case, Inner – A rigid, cup-shaped component of a
seal assembly, which is placed inside the outer seal
case.
Case, Outer – The outer thin-wall rigid structure of
the lip-seal assembly which contains the inner case,
the primary-seal ring, the spring parts, and the
secondary seal.
Case, Seal – A rigid member to which the seal lip
is attached.
Case Width – The total axial width of the seal case.
Cavity, Mold – A single unit or assembly of
contoured parts in which a material, such as an
elastomer, is shaped into a particular configuration.
Cavity, Seal – The annular area between a housing
bore and a shaft, into which a seal is installed.
Chamfer – A surface that has a groove cut in it or
the edge or corner is cut off; beveled.
Cocked – An installation in which the plane of the
outside seal face is not perpendicular to the shaft
axis.
Compound – A substance or material formed
by the combination of two or more otherwise
independent elements.
Contaminants – Foreign matter on the seal
surface.
Contact Pressure – The average pressure exerted
by a seal on a shaft. This pressure is computed
dividing the total lip force by the total lip area. Also
referred to as radial load.
Counterface – The end of a bearing, a washer, a
steel stamping, or even the back of an oil seal shell.
Cover Plate – Metal plate used to compress all
rubber (HS) seals in the bore and hold them
securely. 87
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