A sealing system includes: a double mechanical seal having a pump-side sealing mechanism (10, 12) and an atmospheric-side sealing mechanism (11, 13); a pump mechanism (19) driven by a rotational shaft (1); a first medium circulation line (30) for circulating a fluid barrier-and-cooling medium between a first chamber (22a) and a second chamber (22b), the first medium circulation line (30) being coupled to the first chamber (22a) and the second chamber (22b), the fluid barrier-and-cooling medium being different from a fluid handled by the centrifugal pump; a heat exchanger (21) and a shut-off valve (28) attached to the first medium circulation line (30); a second medium circulation line (31) bypassing the shut-off valve (28); and a medium pressurizing pump (45) and an on-off valve (23) attached to the second medium circulation line (31).

A mechanical seal system configured to inhibit the emission of process gas from a rotating machine. An annular plunger is axially slidable between a inboard closed position and an outboard open position such that when the plunger is in the closed position, the plunger inhibits the flow of the sealing fluid between the inlet passageway to the seal interface, and when the plunger is in the closed position, the plunger enables the flow of the sealing fluid between the inlet passageway and the seal interface. A biasing mechanism and solenoid provide opening and closing forces to the plunger. Normally-open and normally-closed configurations are provided.

A mechanical seal system configured to inhibit the emission of process gas from a rotating machine. An annular plunger is axially slidable between a inboard closed position and an outboard open position such that when the plunger is in the closed position, the plunger inhibits the flow of the sealing fluid between the inlet passageway to the seal interface, and when the plunger is in the closed position, the plunger enables the flow of the sealing fluid between the inlet passageway and the seal interface. A biasing mechanism and solenoid provide opening and closing forces to the plunger. Normally-open and normally-closed configurations are provided.

A dry gas mechanical seal system configured to inhibit the emission of process gas. The mechanical seal system having tandem first and second stage seals, and a single separation gas supply subsystem configured to direct a supply of separation gas from an inlet through interfacing portions of the first stage seal into a process cavity and from the inlet through the interfacing portions of the second stage seal and out through an outlet to the atmosphere, thereby inhibiting the emission of process gas between a compressor housing and a rotating compressor shaft.

A seal assembly for a rotary machine is positioned between a rotating component and a stationary component of the rotary machine. The seal assembly includes a seal bearing face that opposes the rotating component and a slide device. The slide device is positioned between different fluid pressure volumes in the rotary machine. The slide device axially moves toward the rotating component responsive to pressurization of the rotary machine. The slide device includes cross-over ports and the seal bearing face includes feed ports. The feed ports extend through the seal bearing face to form an aerostatic portion of a film bearing between the seal bearing face and the rotating component. The seal bearing face and/or the rotating component is a non-planar surface that, during rotating motion of the rotating component, forms an aerodynamic portion of the film bearing between the seal bearing face and the rotating component.

A seal assembly for a rotary machine is positioned between a rotating component and a stationary component of the rotary machine. The seal assembly includes a seal bearing face that opposes the rotating component and a slide device. The slide device is positioned between different fluid pressure volumes in the rotary machine. The slide device axially moves toward the rotating component responsive to pressurization of the rotary machine. The slide device includes cross-over ports and the seal bearing face includes feed ports. The feed ports extend through the seal bearing face to form an aerostatic portion of a film bearing between the seal bearing face and the rotating component. The seal bearing face and/or the rotating component is a non-planar surface that, during rotating motion of the rotating component, forms an aerodynamic portion of the film bearing between the seal bearing face and the rotating component.

A seal includes a mating ring that rotates relative to a porous carbon primary ring at a seal interface. A buffer gas is provided into the seal and passes from the back of the primary ring to the seal interface. The seal can be used as a separation seal or in combination with another seal.

A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

A sealing device includes a flexible seal (10), a source of gas (15), a gas inlet (14) into the seal, and a gas outlet (17) from the seal 10, 17 whereby gas flows through the seal. A cryogenic source cools the seal and the gas from the cryogen helps seal the seal to the roll and to keep the seal flexible as the gas flows.