A shaft seal system to prevent pressurized working substances contained within a rotary machine from escaping to surrounding areas of relatively lower pressure includes a first seal disposed between a high pressure region and a first region operating at a relatively lower substantially constant pressure. A second seal is disposed between the high pressure region and a second region operating at a relatively lower variable pressure. Sealing fluid is delivered to the high pressure region whereat the fluid flows axially in opposite directions along the shaft to the first and second regions. The flow of fluid toward the second region is restricted to a greater degree than the flow of fluid toward said first region. Changes in the flow of fluid through said first and second seals to the first and second regions resulting from changes in the operating pressure of the second region are monitored. A valve regulates the flow of sealing fluid to the high pressure region in accordance with the monitored changes in fluid flow to maintain a substantially constant flow of fluid toward the first region irrespective of changes in the operating pressure of the second region.

Shaft seal assembly for a rotary machine

Cryogenic liquid coolant is transferred from a stationary liquefier through a bayonet to the rotor of a superconducting generator using a cryogenic fluid transfer joint cantilevered on the collector end of the rotor. Pressure of the boil-off coolant is employed to prevent the liquid coolant from entering a relative-motion gap about the bayonet, while the boil-off coolant flows through the gap to reduce heating of the bayonet. Flow of noncryogenic gas is used to regulate flow of the boil-off coolant and to minimize contamination of the coolant by bearing lubricant.

Cryogenic fluid transfer joint employing gaseous seals

The condensate of a closed cycle power plant that uses an organic working fluid for lubricating the bearings of the turbine is cooled to a temperature below the condenser temperature by an auxiliary cooler before being supplied to the bearings. This subcooling of the lubricating liquid increases its viscosity to a value which causes the minimum thickness of the lubricating film in the bearings to be increased significantly. By increasing the minimum film thickness, the filtering demands on the lubricating condensate are reduced and the surface finish of the journals and bearings is less critical permitting the journals and bearing to be finished by standard precision grinding techniques. In a specific embodiment of the invention, a cannister housing the turbine/generator is provided with a sump for collecting liquid working fluid which is delivered to the bearings through a cooler. Where the prime mover is coupled to a generator through a gear box, all of which are contained in the sealed cannister, the viscosity of the condensate may be increased to such a level that the cooled working fluid is adequate to lubricate the gear box itself.

Lubricating system for organic fluid power plant

The invention is a system and method for sealing about a shaft employed for conveying power between the interior of a working chamber having working fluid under high pressure, and the exterior of such chamber. The working fluid is sealed from escape along the shaft by interposing a liquid lubricated seal to sustain substantially all of the pressure differential, and between the working chamber and the lubricated seal interposing a second seal employing a sealing fluid which is preferably gaseous at the temperatures and pressures to which it is subjected. This second seal fluid is not significantly soluble in the first seal fluid used in the lubricated seal and is compatible with the working fluid used in the working chamber. The second sealing fluid is recirculated in a closed cycle in a manner to sweep the working fluid away from the lubricant and the lubricant away from the working fluid, there being provision for drawing off portions of the first and second seal fluids between the two seals and separating them from one another for reuse, and for drawing off the remaining portion of the second seal fluid and a portion of the working fluid between the second seal and the working chamber and separating the second seal fluid and working fluid from one another for reuse. Condensation and gravity separation are employed in the separations mentioned.

Seal system and method

A compressor or turbine type rotary machine for compressing or expanding a dangerous gas, e.g. a gas that is toxic or explosive, comprises a closed enclosure formed outside the stator around a shaft passage receiving the shaft of the rotor, the enclosure being delimited by a bell and being filled with a liquid under pressure, a wet type mechanical seal being disposed between the rotor shaft and the stator, inside the stator. The liquid contained in the enclosure is put under pressure, and a magnetic coupling is provided to link the rotor shaft to an outside shaft. The invention makes it possible to prevent any leakage of dangerous gas from the inside to the outside of the rotary machine.

Compressor or turbine type rotary machine for compressing or expanding a dangerous gas

In a power system including a shaft driven by expanding a working fluid in a turboexpander and a housing surrounding the shaft and the rotor of the turboexpander, a seal is provided between a process zone containing the rotor and a lubricant zone by injecting a seal fluid into the housing between the two zones at a relatively high pressure. The seal fluid is preferably comprised of the lightest constituent of the working fluid, and the system includes means for recovering the seal fluid from the lubricant and from the working fluid and recycling it.

J Swearingen

Papers

Lubricating and sealing system for a rotary power plant