Page 168 - SKF-bearing-housings

Split plummer block housings SNLN 30 series

Felt seals steel end covers should be used. These can be
Felt seals are simple and effective. At circum- cut from sheet steel and placed in the seal
ferential speeds above 4 m/s, a small gap groove. Use a hollow silicone rubber cord to
forms between the felt and shaft, transform- hold the cover in place.
ing the contact seal into a non-contact, gap- For housings from size 3034 to 3056, the
type seal. end covers are made of grey cast iron and are
suitable for operating temperatures from –50
to +200 °C (–60 to +390 °F). They are inserted,
Labyrinth seals together with a hollow silicone rubber cord, in
For applications where there are high speeds the housing seal groove.
or extreme temperatures, SKF recommends Details of the permissible length of the shaft
using labyrinth seals. Labyrinth rings, mounted end are provided in table 4.
on the shaft, form a multi-stage labyrinth seal
with the housing seal grooves. Hollow, silicone
rubber cords, supplied with the rings, hold the Using sealed bearings
rings in place on the shaft.
Using sealed bearings in housings with stand-
ard seals is a good solution for highly contam-
Taconite heavy-duty seals inated environments. The sealed bearing
For bearing arrangements that must operate together with the housing seal and grease
under highly contaminated conditions, such as provide three layers of protection († SKF
those encountered in mining, taconite heavy- three-barrier solution, page 39).
duty seals, which can be filled with grease, are SNLN 30 housings can be used together
recommended. Grease enhances the sealing with SKF sealed self-aligning bearings. When
effect and extends the service life of the seals. using taconite heavy-duty seals, a sealed
Taconite heavy-duty seals are labyrinth seals bearing does not enhance the sealing effect
combined with a V-ring seal. The labyrinth during operation, but still protects the bearing
ring is solid but the main body of the seal is against contaminants during mounting.
split.
SNLN 30 housings from size 3024 to 3032
accommodate taconite seals with a radial
laby rinth. SNLN 30 housings from size 3034
to 3056 accommodate solid taconite seals
with an axial labyrinth. Both can be relubri-
cated via a grease fitting in the main body of
the seal.
The axial movement of the shaft relative
to the housing is limited to ±1,5 mm for shaft
diameters ranging from 110 to 150 mm,
±2 mm for shaft diameters ranging from
160 to 200 mm and ±4 mm for larger shaft
diameters.

End covers
Housings at the end of a shaft should have an
end cover that fits into the seal groove in the
housing.
For housings from size 3024 to 3032, the
end covers are made of plastic and are suitable
for operating temperatures from –40 to
+110 °C (–40 to +230 °F). For applications
where temperatures exceed 110 °C (230 °F),

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