Variable friction secondary seal for face seals

摘要

Vibration and stability of a primary seal ring 18 is controlled by a secondary seal system 24. An inflatable bladder 26 which forms a portion of secondary seal varies the damping applied to this seal ring. The amplitude of vibration of the primary seal ring 18 is sensed with a proximity probe 34 that is connected to a microprocessor in a control system 32. The bladder pressure is changed by the control system 32 to mitigate any sensed instability or vibration.