Additional design features
There are different ways to connect the stainless steel garter springs of HS and HSF seals. A threaded spring connection (fig 1) is used for all HSF seals unless otherwise specified and for the solid HS4 and HS5 seals as well as the split HS6 and HS8 seals for shaft diameters ≤ 455 mm (18 in.). A hook-and-eye spring connection (fig 2) is used for HS6 and HS8 seals for shaft diameters > 455 mm (18 in.). All HS7 seals feature the special control-wire connection (fig 3), available only for these seals.
Spacer lugs are available for all metal-cased designs to separate seals in tandem or back-to-back arrangements to provide space for sealing lip lubrication (fig 4).
Traditional fixed-width lugs for metal-cased HDS seals are 9,5 mm (0.375 in.) in diameter and are available in widths from 3,2 mm (0.125 in.) to 12,7 mm (0.5 in.) in increments of 1,6 mm (0.063 in.). The fixed-width lug is an available option for all metal-cased seals.
All standard adjustable lugs are 9,5 mm (0.375 in.) in diameter and 9,5 mm (0.375 in.) in width. They can be adjusted to smaller widths in 1,6 mm (0.063 in.) increments by removing the steel washers. The lugs may also be removed entirely. Longer, adjustable lugs, with a width of 12,7 mm (0.5 in.), are available on request, however, it can be more difficult to reduce their width.
Certain small seal cross sections may require special small diameter lugs, 5,3 mm (0.210 in.), with a width range of 1,6 to 3,2 mm (0.063 to 0.125 in.).
The lugs are placed around the heel of the seal in four, six or eight equally spaced locations, depending on the seal outside diameter (table).
Fixed-width lugs are available for HDL seals on request.
The SKF Springlock is a sealing lip feature that surrounds 270° of the garter spring diameter (fig 5). It helps hold the spring in position during installation and is standard on all HS seals and spring-loaded, metal-cased HDS seals.
For blind installations, where spring displacement may go undetected, the SKF Springcover can be specified (fig 6). It also protects the spring from dirt, water and other contaminants. SKF Springcover is flexible and covers the exposed portion of the stainless steel garter spring without adversely affecting the spring’s capability.
SKF Bore Tite Coating
SKF Bore Tite Coating is a water-based acrylic sealant available on most SKF metal-cased seals. The sealant is used as a coating on the outside diameter of the seal (fig 7). SKF Bore Tite Coating is pliable with a thickness of 0,03 to 0,07 mm (0.0012 to 0.0028 in.) to help accommodate small imperfections in the housing bore surface. It can be used at temperatures up to 200 °C (390 °F) and is compatible with most oils, greases, aqueous acids and alkalis, alcohols and glycols. Note that SKF Bore Tite Coating is not compatible with aromatics, ketones or esters. Contact with these substances will, however, have little or no effect if wiped off quickly.