The performance of a dynamic PTFE seal depends greatly on the pressure and shaft velocity involved. In reality, a seal is in contact with only a small area of rotating shaft, which means that the dynamic forces and energy are going to be concentrated there. Much of the energy that comes from the shaft is going to be dissipated in two forms: wear and frictional heat, both of which can reduce the useful life of a seal. An increase in the force that holds the seal lip against the shaft or an increase in the speed of the shaft makes the effects of wear and heat even worse.
