General Electric Company

Adrian Missana

Jens Kure-Jensen

Steven Paul Scarlata

Russell A Gary

A shaft sealing system for a steam turbine includes at the high-pressure inlet end an outer air seal (40 ) and an outer steam seal (42 ) each comprised of segmented circumferential seals and a plurality of labyrinth seals (44, 46, 48). The low-pressure end of the turbine is provided with a segmented circumferential seal (60) substantially precluding ingress of air past the seal. The steam leaking past the inner two labyrinth seals (46 and 48) is returned to a stage of the turbine by a first leak-off pipe system (50). Air leaking past the air seal and steam leaking outwardly past the outer steam seal (42) is piped to the main condenser (58). High-pressure steam between the outer steam seal (42) and the outermost labyrinth seal (44) is piped via a second leak-off path (56) to a turbine stage downstream from the first-mentioned turbine stage.

Shaft sealing of steam turbines

Linear electric actuators powered by DC brushless servomotors are individually controlled to position steam turbine valves by way of levers, pins and links to thus eliminate hydraulics and the attendant disadvantages of fluid filtering, conditioning and leakage as well as obtaining more flexible individual valve control, vis-a-vis, camshaft operated hydraulic actuators. Additionally, low friction actuators and springs are employed to automatically close the turbine valves in the event of a power failure.

Electric actuators for steam turbine valves

An apparatus for continuously monitoring the alignment condition of a thrust bearing based on a pair of temperature differences is adapted to utilize either analog or digital means. The monitor is particularly applicable for use in large turbines, particularly those coupled to generators for the production of electric power. Bearing misalignment and other variables are determined from temperature measurements of the oil feed temperature and from two temperature measurements made on diametrically opposite portions of the bearing surface. The apparatus of the present invention is made possible by observed predetermined relations between certain computed temperature differences which relate bearing thrust and misalignment moment and which also relate minimum oil film thickness and actual misalignment slope.

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Scotia, NY, United States of America

Adrian Missana