摘要 |
A system for maintaining a tightness between two parts rotatable relative to each other. The system includes at least two sealing units, with each of the sealing units having at least two possible states or conditions, namely, a first state or condition for ensuring a tightness between the two parts and a second state or condition wherein it does not ensure a tightness. Each sealing unit is deformable and includes a drive arrangement for intermittently actuating each of the sealing units.
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