| 摘要 |
780,537. Stuffing-box substitutes. AKT.- GES. FUR TECHNISCHE STUDIEN. June 7, 1955 [June 19, 1954], No. 16350/55. Class 122 (5). A liquid sealing arrangement for packing the shaft of a turbine or compressor, particularly in a closed cycle thermal power plant wherein a gaseous working medium circulates under variable pressure depending on operating load conditions, comprises a chamber 5 sealed from the atmosphere by a liquid seal 4 and communicating through a restricted flow path with a second chamber 6 supplied with working medium which is maintained at a pressure above the pressure in the first chamber by a differential pressure actuated valve 15. The shaft 2 of the turbine of a power plant is provided with spaced labyrinth packings 7, 8 and the chamber 6 between the packings is supplied through ducts 9, 10 and 11 with sealing gas from a point in the plant circuit at a pressure higher than that in the turbine outlet 3. The chamber 5 is connected by conduits 12 and 13 to a container 14 in which the pressure is maintained at a value lower than that in the chamber 6 by means of the valve 15 biased to close by the pressure in duct 10 and to open by the pressure in the container and a tension spring 18. When the valve 15 is open, gas escapes via a duct 19 from the container 14 until a predetermined pressure difference exists between the chambers 6 and 5. Sealing gas in the chamber 6 therefore flows through the packings 7 and 8 towards the turbine rotor 1 and to the chamber 5 respectively and gas leakage from the latter is prevented by lubricating oil fed under pressure through a duct 20 to the combined bearing and oil seal 4, A pump 21 draws the oil from a reservoir 22 and delivers it to the duct 20 via ducts 23 and 27 and a throttling device 26 comprising two interconnected pistons 28, 29, the space below the piston 28 being connected to the duct 27 by a duct 30 and the space above the piston 29 being connected by a duct 31 to the container 14. The pistons are urged downwardly to open the duct 27 by a spring 32 so that the pressure in that duct always exceeds by a predetermined amount the pressure in the container. Lubricating oil is also supplied from the duct 27 via a duct 42 to the compressor bearing 33 and the compressor shaft 35 is sealed in a similar manner to the turbine shaft by sealing gas fed from the duct 10 to a chamber 41 between labyrinth packings 39, 40. The level of oil in the container 14 is maintained constant by a spring loaded valve 44 that is opened by the oil pressure in duct 47 when the float rises to a predetermined height and closes outlet 51 from the space under the valve piston 49, oil then returning via duct 45 to the reservoir 22. The throttle device 26 may be loaded by a weight instead of by the spring 32.
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