Fluid-cushion sealing device

A fluid-cushion sealing device for a piston, wherein:

• said sealing device is configured to move in longitudinal translation in a cylinder, along an axis of the cylinder, said piston and said cylinder defining, with at least one cylinder head, a chamber to be sealed, wherein the sealing device comprises:
• at least one continuous perforated ring which comprises an internal cylindrical ring surface, an external cylindrical ring surface, and two axial ring surfaces, said ring being configured to be accommodated in at least one ring groove provided in the piston or in the cylinder, while said ring is capable of moving radially in the ring groove without being able to leave the ring groove, said continuous perforated ring being sufficiently flexible to allow the diameter of the continuous perforated ring to increase or decrease relative to said groove under an effect of a pressure of a source of pressurized fluid;
• a ring seal that produces a seal between each axial ring surface and the ring groove, so that the ring groove defines, with the continuous perforated ring, a pressure distribution chamber connected by a transfer circuit to a pressurized fluid source;
• at least one calibrated opening which passes right through the continuous perforated ring in its radial thickness;
• at least one fluid-cushion carrying surface which the continuous perforated ring comprises, said carrying surface being arranged on the opposite side from the pressure distribution chamber.