In most shaft seal applications, it is the shaft that is in motion. In some instances, however, the housing bore may be in rotation, meaning that sealing is necessary on the seal O.D. rather than the I.D. (which will be stationary).

Figure 83 shows a spring-loaded single lip design for O.D. sealing. Figure 84 shows spring-loaded dual lip seal for O.D. sealing.

“Though the standard shaft seals shown previously are ideal for a wide variety of applications, they are not the best solution to every design problem.”

Figures 83 & 84