Industrial shaft seals

gab.ru
V-ring
Берг
seals
АБ bergab@ya.ru Тел. (495)-228-06-21, факс (495) 22
Fig 91
Fig 92
The spiral groove (fig 91) should have an
enlargement of approximately 2 mm for each
complete turn in the direction of rotation and
should have a depth of between 0,05 and
0,1 mm with a radius of curvature of approximately
0,5 mm. All edges must be
smoothed.V-rings may also be used as a
secondary back-up seal (fig 92), for example,
where it is necessary to protect the sealing lip
and counterface of the primary seal against
solid contaminants or corrosion. They have
also been used to advantage to enhance the
efficiency of labyrinth seals (fig 93). If the
seating diameter lies in the appropriate range
for two V-rings, the larger V-ring should
always be chosen.
Materials
Normally V-rings are made from nitrile rubber
(NBR). This has good resistance to wear as
well as to chemicals and can be used for
normal operating temperatures. For applications
where higher temperatures occur or
where aggressive media are present, V-rings
made of fluoro rubber (FPM) can be supplied.
The permissible operating conditions will be
found in table 26. The chemical resistance of
the rubber materials is described in the section
entitled “Chemical resistance”. In the product
table under the heading “Design and material”,
the letters R and V are used to identify nitrile
rubber and fluoro rubber, respectively.
Warning: fluoro rubber seals will give off
toxic fumes at temperatures above 300 °C. If
overheated they are still dangerous to handle
even once they have cooled down.
Sliding velocities
V-ring seals can be operated under the
conditions given in table 26. It should be
noted that at speeds above 15 m/s the sealing
lip will lift from the counterface and the V-ring
will only act as a gap-type seal.
Fig 93
gab.ru 326Берг АБ bergab@ya.ru Тел. (495)-228-06-21, факс (495) 22