SKF - Industrial Shaft Seals

Multiple HS seal installations
When installing two split all-rubber HS seals in
one cavity, the locations of the split joints should
be staggered by 30° to 60° to minimize the risk
of leakage through the joints. The splits should
be located toward the top of the bore. Grease
the cavity between the seals to provide lubricant
to the outer sealing lip.
When two HS seals, split or solid, are installed
in the same housing bore, a spacing washer must
be placed between the two seals († fig. 27).
Suitable washer dimensions can be determined
based on the shaft and housing bore diameters,
d 1 and D, respectively:
Cover plate
New seal cavity plate
Seal-retaining
cover plate
Sealing element
6,35 – 12,7 mm
Fig. 26
2
washer inside diameter
= d 1 + 6 to 10 mm (0.25 to 0.4 in.)
washer outside diameter
= D – 0,5 to 1,5 mm (0.02 to 0.06 in.)
Spacing washer
Fig. 27
The width of the washer is determined by the
application conditions. There should, however,
always be sufficient room for lubrication holes
to be provided in the circumference, or lubrication
grooves in one side face († fig. 28). These
lubrication provisions must enable grease to be
supplied from the housing to the sealing lips via
a drilled passage or grease fitting († fig. 29 on
page 84). When determining what washer width
is appropriate for the depth of a housing bore, it
is ne cessary to consider the axial displacement
required when clamping the seals.
Fig. 28
Details of spacing washer for central lubrication
A separator between two seals can be a slotted washer to promote distribution of the lubricant.
d 1 + 6,4 mm
(d 1 + 0.25 in.)
D – 0,5/1,5 mm
(D – 0.06 in.)
83