Abstract: A seal arrangement located between a lubricated chamber and a pressurized chamber pressurized by a gas at a variable pressure. The seal arrangement includes a seal around a shaft extending into the lubricated and pressurized chambers through a wall separating the chambers. The seal slides along the shaft between a first and a second abutment position via a variable pressure exerting a force on an end face, i.e., a casing, of the seal. The casing, the shaft and seal define a clearance allowing air to pass from the pressurized chamber to the lubricated chamber. Springs urge the seal toward the first abutment position against the variable pressure and have a strength so that, when the variable pressure is under a predetermined value, the clearance is sealed. When the variable pressure is over a predetermined value, the seal slides to the second abutment position and the clearance is opened to allow the pressurized gas to flow from the pressurized chamber to the lubricated chamber.

Abstract: A device for ensuring the sealing in a rotary machine between a rotor and fixed blade stages.Blade edges are joined by rings carrying circular seals in slots. Springs force the seals in the longitudinal direction towards transverse faces of reinforcements of the rotor.A turbulence-free gas flow is obtained as a result of the total seal obtained by the seals (19). Moreover, the rotor can be constructed with a substantially rectilinear ferrule which only induces limited stress concentrations.