Rotary kinetic fluid motors or pumps – Casing and spaced housing with space vented to working fluid
Reexamination Certificate
1999-11-01
2002-01-29
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Casing and spaced housing with space vented to working fluid
C415S175000
Reexamination Certificate
active
06341937
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a steam turbine and, in particular, to a steam turbine with an improved cooling system for the casing.
2. Description of the Related Art
With reference to
FIG. 3
, a prior art stream turbine includes a rotor
100
extending along a longitudinal axis, and a casing
102
enclosing the rotor
100
. A high pressure turbine portion
103
, an intermediate pressure turbine portion
104
and a lower pressure turbine portion
105
are disposed within the single casing
102
around and along the rotor
100
.
Provided within the casing
102
is a dummy ring
110
which separates the high and intermediate pressure turbine portions
103
and
104
and seals therebetween. The dummy ring
110
and the casing
101
define a space
118
therebetween. The space
118
is filled with steam so that the steam within the space
118
is held there. The steam within the space
118
is heated by thermal transfer from the high pressure and temperature steam supplied to the high pressure turbine portion
103
so that the portion of the casing
102
enclosing the space
118
is also heated. This results in the thermal deformation of the casing
102
.
SUMMARY OF THE INVENTION
The invention is directed to solve the above mentioned prior art problems, and the objective of the invention is to provide a steam turbine with an improved cooling system for the casing.
The invention provides a steam turbine which includes a rotor which extends along a longitudinal axis and has at least two different pressure turbine portions disposed around and along the rotor. Each of the turbine portions has multiple stages. A casing encloses the rotor and has at least one steam inlet. A dummy ring is provided stationarily around the rotor to separate and seal between the two different pressure turbine portions. The dummy ring defines a nozzle chamber for receiving the steam from the steam inlet port and a plurality of nozzles for directing the steam from the nozzle chamber toward the higher pressure turbine portion. The dummy ring and the casing define a space therebetween. The space is fluidly connected to the higher pressure turbine portion. Piping extends between the space and a steam passage downstream of the last stage of the higher pressure turbine portion. The steam passage allows the steam within the space to flow to the steam passage downstream of the last stage of the higher pressure turbine portion to cool the casing.
REFERENCES:
patent: 2796231 (1957-06-01), Hertl
patent: 5149247 (1992-09-01), Gros et al.
patent: 5388960 (1995-02-01), Suzuki et al.
patent: 0-926-316 (1999-06-01), None
Magoshi Ryotaro
Nakano Takashi
Look Edward K.
McAleenan James M
Mitsubishi Heavy Industries Ltd.
Wallenstein & Wagner Ltd.
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