SKF - Industrial Shaft Seals

PTFE materials
The selection of seal materials typically requires
a compromise between advantages and disadvantages.
There are hundreds of different PTFE
materials with a variety of fillers. Common fillers
include glass fibre, carbon, graphite, molyb denum
disulphide, metal oxides and various polymers.
Each possesses different properties, appropriate
for different applications and service conditions.
Common to all filled PTFE materials are their
improved resistance to wear and deformation.
Unfilled PTFE provides, in most cases, a lower
coefficient of friction than a filled PTFE material
and the lowest degree of wear of the seal counterface.
However, a sealing lip made of an unfilled
PTFE material has limited resistance to wear
and deformation under load.
The PTFE materials that SKF most often recommends
are listed in table 14 on page 176.
In addition to PTFE-based compounds, SKF also
offers radial shaft seals in other modified plastics,
some of which are listed in table 15 on
page 177.
Selecting the appropriate material for the
metal case and the O-ring(s) is also of significant
importance to achieving satisfactory sealing
performance. Contact SKF for more information.
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Installation
Special care must be taken during handling and
installation of PTFE seals. For more information,
refer to pages 85 and 86.
Size range and availability
The majority of PTFE radial shaft seals from SKF
are made to order to meet the demands of each
application. There are, however, certain standard
sizes within the ranges of approximately 6 to
200 mm (0.250 to 8 in.) shaft diameter and approximately
16 to 230 mm (0.630 to 9 in.) bore
diameter. Contact SKF for more information regarding
designs and sizes.
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