ERIKS type GV (type C according to DIN) is equivalent to type M, but is a heavy-duty version with a double metal casing. This can be a useful solution with larger diameters in more demanding applications. There is also a version of this type with a dust lip; the GVST (type CS according to DIN).

The group of oil seals used in dynamic applications include radial shaft seals that seal a rotating shaft around its circumference. They are also known as lip seals, but in this blog we will use the term oil seals.

Manufacturing and Quality Control

What are Oil Seals – A guide to Oil and Rotary Shaft Seals

Almost every lip seal is constructed to have a flexible inner part that creates a dynamic seal on the moving shaft, as well as a hard outer casing that statically matches the machine-end cover. The flexible part is made from different grades of rubber, while the hard part is made of light-gauge metal or strong plastic.

Vulcanizates of several fluoroelastomers, listed in Table 14.1, were exposed to a standard 5W-30 engine oil, ASTM Service Fluid 105, for up to 6 weeks at 150°C (302°F).⁵ The oil was changed weekly, but was not aerated. Retained elongation was measured after exposure for 1, 2, 3, and 6 weeks; data are shown in Fig. 14.3. The results indicate that bisphenol-cured FKM-A500 VDF/HFP copolymer, FKM-B600 VDF/HFP/TFE terpolymer, and peroxide-cured FEPM-7456 TFE/P/VDF terpolymer lost most of their original elongation over the course of the test exposure, indicating considerable additional cross-linking occurred by reaction with amine- and phenol-containing oil additives. The other fluoroelastomers showed better retention of elongation, being much less susceptible to additional crosslinking. Note that FEPM-7456 contains a high level of VDF (about 30%), while FEPM-7506 contains a relatively low VDF level (10–15%) to serve as cure site for bisphenol curing. The other FEPM types contain no VDF.