Rotary kinetic fluid motors or pumps – Including means for handling portion separated from working... – Moisture or liquid separated from gaseous working fluid...
Reexamination Certificate
2000-07-12
2002-04-23
Verdier, Christopher (Department: 3745)
Rotary kinetic fluid motors or pumps
Including means for handling portion separated from working...
Moisture or liquid separated from gaseous working fluid...
Reexamination Certificate
active
06375417
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to steam turbines and, more specifically, to an improved moisture removal pocket for providing an improved moisture removal efficiency.
Steam turbines frequently operate in the wet region, that is at pressures and temperatures that cause steam to condense so that a significant fraction of the mass flow is in the form of liquid water. The presence of liquid water in the steam vapor flow gives rise to a thermodynamic loss associated with accelerating water droplets to vapor velocity. In addition to degraded thermoefficiency, the moisture content can lead to increased water impact erosion of the later stage buckets.
Moisture removal pockets are commonly used to extract water from the flow path by collecting droplets centrifuged from the bucket trailing edge surfaces. A more recent approach for removing this moisture is to groove the leading edges of the buckets (or blades) to capture the water and to use centrifugal force generated by the rotating turbine rotor to drive the water out to stationary moisture collection devices or pockets. The collection efficiency of such moisture removal pockets, however, is quite low; typically on the order of 10 to 20%. The prior art includes a great number of configurations adapted to remove moisture from the moisture laden motive steam passage of the steam turbine. A number of these configurations have included various combinations of multiple slots, pockets, baffles, segmented bucket covers, side wall scoops and the like. However, a need remains for a moisture removal device providing a higher efficiency than the 10-20% efficiency noted above.
BRIEF SUMMARY OF THE INVENTION
A moisture removal pocket configuration and disposition is proposed as an embodiment of the invention to provide a significant improvement to moisture removal efficiency. The moisture removal device of the invention is easy to produce and involves no components that would disturb the flow of steam vapor phase. As described below, the invention proposes to modify an existing design in a manner which meets low disturbance and producibility requirements.
More specifically, the invention is embodied in the provision of a moisture removal pocket having a slot for the flow of moisture thereinto, wherein a substantial portion of the slot axially overlaps a respective bucket cover. The substantial overlap provides access to the pocket for water that moves as a film along the nozzle outer side wall and is entrained in the leakage jet above the bucket cover. The substantial overlap may be provided by eliminating an upstream gutter segment of the conventional moisture removal pocket, so that the overlap can be achieved while meeting axial space in constraints.
REFERENCES:
patent: 2121645 (1938-06-01), Warren
patent: 3058720 (1962-10-01), Hart
patent: 5261785 (1993-11-01), Williams
patent: 125365 (1967-11-01), None
patent: 509 266 (1930-10-01), None
patent: 547332 (1932-03-01), None
patent: 759 964 (1953-04-01), None
patent: 368403 (1963-05-01), None
patent: 1951922 (1971-04-01), None
patent: 1 510 108 (1968-01-01), None
patent: 387361 (1933-02-01), None
patent: 388156 (1933-02-01), None
patent: 993 476 (1965-05-01), None
patent: 1386718 (1988-04-01), None
Hofer Douglas Carl
Maddaus Alan Donn
Mollo Nicholas Joseph
General Electric Company
Nixon & Vanderhye PC
Verdier Christopher
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