Nozzle box

Details Nozzle box Nozzle box

1999-01-11

2001-03-06

Look, Edward K. (Department: 3745)

Rotary kinetic fluid motors or pumps

Working fluid passage or distributing means associated with...

Plural distributing means immediately upstream of runner

C415S202000, C415S208200, C415S209200, C415S209300

Reexamination Certificate

active

06196793

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates generally to turbines, and more specifically, to a nozzle box for increasing the efficiency of a flow directed to a turbine.
By way of a more detailed background, and with reference to
FIG. 1
, a control or first stage
10
of a conventional turbine includes a nozzle box
12
surrounding a rotor
14
, the turbine control stage represented by a single bucket
16
. Nozzle box
12
generally includes a torus portion
18
, a bridge ring assembly
20
and a partition ring assembly
22
. In turbines of this type, steam is fed into torus portion
18
of nozzle box
12
, and is directed axially between outer bridge ring
24
and inner bridge ring
26
, and between a plurality of circumferentially spaced bridge elements
28
, which bridge elements
28
connect rings
24
and
26
. The steam then flows through partition ring assembly
22
towards bucket(s)
16
. Partition ring assembly typically comprises of radially inner and outer bands
30
and
32
(each formed in 180° segments which, when the turbine is fully assembled, form 360° rings), respectively, which hold between them a large number (for example, 100) of vane-shaped partition elements
34
, which partition elements
34
serve to direct the steam at a desired angle to the bucket blades. Steampath assembly
22
is welded in place between upper and lower rings
24
,
26
by circumferentially extending welds
36
,
38
. Rings
24
,
26
are, in turn, welded to torus
18
by means of circumferential welds
40
,
42
. Nozzle box
12
is supported within a turbine inner shell
44
by a plurality of lugs
46
(one shown) welded to the outside of torus
18
and bridge ring assembly
20
, in an area radially adjacent partition ring assembly
22
. Nozzle box
12
is also keyed to inner shell
44
at
48
.
Within conventional nozzle box designs, however, there exists significant circumferential variation in the cylindrical flow angle and a hub-strong velocity profile of the flow entering the first stage nozzle. This type of inlet distortion can lead to a significant loss in first stage efficiency.
Accordingly, there is a need in the art for an improved nozzle box.
SUMMARY OF THE INVENTION
An apparatus and method for directing a flow of fluid to a turbine via a nozzle box mountable to encircle a shaft is disclosed. The nozzle box includes a housing having an inner wall spaced from an outer wall and joined therewith so as to form a chamber. The housing also includes at least one inlet and at least one outlet, each in fluid flow communication with the chamber. A plurality of radially projecting nozzles are positioned between the inner and outer walls and located upstream of the outlet for directing the flow of fluid through the outlet. A flow distributor is positioned between the inner and outer walls and located upstream of the nozzles for directing the flow of fluid through the chamber and to the nozzles. The flow distributor is configured to maintain a substantially uniform flow of the fluid to the nozzles.


REFERENCES:
patent: 3804335 (1974-04-01), Sohre
patent: 5259727 (1993-11-01), Quinn
patent: 5392513 (1995-02-01), Mazzola
patent: 5927943 (1999-07-01), Maier
patent: 61-053403 (1986-03-01), None
patent: 61-129409 (1986-06-01), None
patent: 61-132704 (1986-06-01), None

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