Page 633 - SKF-bearing-housings

Sealing solutions

Housing material Sealing solutions
SKND housings are made of spheroidal graphite
cast iron. Cast steel is available on request. SKND housings are equipped with a heavy-
duty NBR double-lip contact seal. The seal
Paint, corrosion protection incorporates a separate metal ring to protect
SKND converter housings are painted blue against hot dust and slag († fig. 6).
(RAL 5007) using a solvent based acrylic Two springs provide tension on the seal so
paint. The paint protects the housing in that it makes positive contact with the trun-
accordance with ISO 12944-2, corrosivity cat- nion shaft. Grease in the chamber above the
egory C2 (i.e. exterior atmospheres with low seal enhances the effectiveness of the seal.
level of pollution, interior atmospheres where When relubricating the seal, the outer lip
condensation may occur) († Environmental allows excess grease and any contaminants
conditions, page 36). The paint is not affected to be purged from the seal cavity. The inner
by most lubricating and engine oils, cutting seal lip prevents contaminated grease from
fluids or alkalescent washing chemicals. Hous- entering the housing.
ings can be repainted with most water or solv- The NBR seal is cut to the proper length to
ent based 1- or 2-component paints. provide a tight fit on the trunnion.
Unpainted surfaces are treated with a solv-
entless rust inhibitor. The designation for lip seals is CS followed by
a size code, e.g. CS 570. The size code is the
shaft diameter at the seal position (attribute
Dimension standards “d b ” listed in the product tables).
The boundary dimensions of SKND housings
are not standardized either nationally or
internationally.

Housing variants

In addition to the three basic housing variants
(see housing design) SKND converter housings
can be tailored with special features to meet
the needs of a particular application. For add-
itional information contact the SKF application
engineering service.
Fig. 6

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