초록 ▼

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

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.

대표청구항 ▼

1. In a system including a working chamber closed to the exterior except for a working fluid inlet and outlet and a shaft passing through an opening in a wall of the chamber, said chamber containing a captive working fluid subject to being evaporated and condensed under pressures and temperatures wi

1. In a system including a working chamber closed to the exterior except for a working fluid inlet and outlet and a shaft passing through an opening in a wall of the chamber, said chamber containing a captive working fluid subject to being evaporated and condensed under pressures and temperatures within predetermined ranges to be employed in the system during operation, and a seal means for preventing escape of said working fluid from said chamber along said shaft, said seal means comprising a lubricant type bearing seal spaced from said chamber with means for injecting lubricant into said bearing seal intermediate its extremities and under pressure greater than the working pressure within said chamber so that part of the lubricant injected will flow in said bearing seal toward said chamber, means for trapping lubricant flowing from said bearing seal toward said chamber before it reaches said chamber, a labyrinth type seal between said chamber and said trapping means, means for injecting a seal fluid into said labyrinth type seal with a portion of the labyrinth seal between the chamber and the point of such injection, and at a pressure great enough to cause the seal fluid to flow toward said chamber and thereby prevent escape of working fluid through said labyrinth type seal means to the point of injection of seal fluid, and cause part of the seal fluid to flow toward and into said trapping means and thereby prevent the flow of lubricant toward said chamber through said labyrinth seal, the improvement which comprises a separator in communication with said trapping means for receiving and separating from one another a mixture of said lubricant and seal fluid so received, condenser means connected to receive such seal fluid as flows through said labyrinth type seal toward said chamber, and for cooling said mixture to condense and separate working fluid from the seal fluid, said means for injecting seal fluid being connected to draw seal fluid from the seal fluid from said separator and condenser means. 2. A system as set forth in claim 1 in which the point of injection of the seal fluid is at the opposite end of the labyrinth type seal from said chamber. 3. A system as set forth in claim 1 in which the point of injection of the seal fluid is directly into said trapping means. 4. A system as set forth in claim 1 in which the point of injection of the seal fluid is at an intermediate point along the length of the labyrinth type seal. 5. The improvement set forth in claim 1 in which said seal fluid is nonreactive and not significantly soluble in either the working fluid or the lubricant. 6. The improvement set forth in claim 1 in which said seal fluid is nonreactive and not significantly soluble in either the working fluid or the lubricant and is of a nature that it is gaseous throughout said pressure and temperature ranges. 7. The improvement set forth in claim 1 in which said predetermined pressure range is superatmospheric throughout the range. 8. The improvement set forth in claim 7 in which the lubricant type seal separates said seal fluid under superatmospheric pressure less than its highest pressure, from ambient atmospheric pressure externally of said system. 9. The improvement set forth in claim 8 in which a portion of the lubricant leakage from said lubricant type bearing seal is directly to the ambient atmospheric pressure and temperature externally of the system, in combination with means for reinjecting said lubricant into the lubricant containing portion of said separator. 10. The improvement set forth in claim 9 in which the space into which said lubricant leakage occurs is enclosed except for an annular labyrinth type opening around said shaft through which it is exposed to the exterior of the system, an auxiliary mechanical seal means engageable within and throughout a speed range of said shaft from zero r.p.m. to a rotary speed less than the normal operative speed of said shaft, to provide a complete mechanical seal of said annular space during periods of nonoperation of the system, so as to prevent leakage of lubricant, seal gas, and working fluid through said annular space when the system is not in operation. 11. In a system including a working chamber closed to the exterior except for a working fluid inlet and outlet and a shaft passing through an opening in a wall of the chamber, said chamber containing a captive working fluid subject to being evaporated and condensed under pressures and temperatures within predetermined ranges to be employed in the system during operation, and a seal means for preventing escape of said working fluid from said chamber along said shaft, said seal means comprising a lubricant type bearing seal spaced from said chamber with means for injecting lubricant into said bearing seal intermediate its extremities and under pressure greater than the working pressure within said chamber so that part of the lubricant injected will flow in said bearing toward said chamber, means for trapping lubricant flowing from said bearing seal toward said chamber before it reaches said chamber, a labyrinth type seal between said chamber and said trapping means, means for injecting a seal fluid into said labyrinth type seal with a portion of the labyrinth seal between the chamber and the point of such injection, and at a pressure great enough to cause the seal fluid to flow toward said chamber and thereby prevent escape of working fluid through said labyrinth type seal means to the point of injection of seal fluid, and cause part of the seal fluid to flow toward and into said trapping means and thereby prevent the flow of lubricant toward said chamber through said labyrinth seal, the improvement which comprises a separator in open communication with said trapping means for receiving and separating from one another a mixture of said lubricant and seal fluid so received, condenser means in open communication with said labyrinth seal between the point of injection of said seal fluid and said chamber to receive such seal fluid as it flows through said labyrinth type seal toward and before it reaches said chamber, together with seal fluid from said separator, and for cooling said mixture to condense and separate any working fluid from the seal fluid, said means for injecting being connected to draw seal fluid from seal fluid from which working fluid has been so separated. 12. The improvement set forth in claim 11 in which said seal fluid is of a nature that is gaseous throughout said pressure and temperature ranges. 13. The improvement set forth in claim 11 in which said means for injecting is capable of maintaining a pressure in said condenser lower than that in said chamber. 14. The improvement set forth in claim 11 in which said means for injecting propels said seal fluid through a cycle including the labyrinth seal means, sump, separator and condenser, said cycle being closed against escape of seal fluid to the atmosphere. 15. The method of preventing leakage of a working fluid at a relatively high pressure along an annulus between a housing enclosing a chamber containing said working fluid and a shaft extending from said chamber through an opening in said housing, to a space at relatively lower pressure exterior of said chamber, comprising injecting a lubricant into said annulus at a point spaced from said chamber and under pressure greater than that of the working fluid in said chamber to cause the lubricant to flow through said annulus in both directions from the point of injection, injecting into said annulus at a point between said chamber and the point of injection of the lubricant, a seal fluid non-reactive with and not significantly soluble in either the working fluid or the lubricant to cause said seal fluid to flow in both directions from its point of injection through said annulus, trapping said lubricant and seal fluid flowing toward one another at a location between said points of injection, whereby there will be a lubricant-seal fluid contact at the location of said trapping, separating the trapped seal fluid and lubricant flowing to the location of said trapping to produce substantially lubricant free seal fluid, chilling the seal fluid flowing toward said chamber from the point of its injection, together with working fluid mixed therewith to separate working fluid therefrom and produce seal fluid substantially free of working fluid, reinjecting the thus separated lubricant and seal fluid, and returning the working fluid separated from said seal fluid to the body of working fluid. 16. The method of claim 15 in which the seal fluid flowing from its point of injection toward said chamber is drawn off before it reaches said chamber and chilled to separate any working fluid therefrom. 17. The method of claim 15 in which the lubricant and working fluid separated from the seal fluid are collected into reserve liquid bodies separated from one another pending reinjection and the seal fluid from which they are separated is collected over said lubricant and working fluid liquid bodies with an interface therewith pending reinjection.