US4403476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for operating a steam turbine with an overload valve
Assignee: General Electric Co
•
Filing: 1981-11-02
•
Granted: 1983-09-13
•
Expires: 2001-11-02
Abstract
Abstract A method is disclosed for operating a steam turbine using turbine reserve capacity for attaining operation at elevated loads. In a preferred form of the invention, a bypass overload valve is provided in parallel with the steam admission control valves but is connected to discharge steam to a lower pressure stage of the turbine. During operation of the turbine at less than full load, the bypass overload valve is maintained closed and the control valves are positioned to sustain a preselected load. As load on the turbine increases, the control valves are increasingly opened until they have all reached their fully opened position corresponding to a nominal rated capacity of the turbine. Then, at the discretion of operating personnel, the bypass overload valve is fully opened while simultaneously one or more of the control valves is throttled to offset any steam passing through the bypass overload valve in excess of the amount required to sustain the preselected turbine load. A throttling reserve is thus established on the control valves which may then be positioned toward their fully opened position to achieve greater power output.
Inventors
- 👤 Lloyd H. Johnson
- 👤 Robert S. Couchman
- 👤 Robert C. Spencer, Jr.
- 👤 John A. Booth
- 👤 Russell J. Holman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:45
CPC Classifications
F; F01; F01D; F01D21/00; F01K; F01K7/00; F01K7/16; F01K7/18; F01K7/20; F01D17/00; F01D17/10; F01D17/105; F01D17/12; F01D17/14; F01D17/141; F01D17/145
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
196 words
A method of operating a steam turbine delivering power to a connected load and adapted to receive steam from a steam generating source, the turbine having a plurality of control valves for controlling the admission of steam to higher pressure stages of the turbine and having a bypass overload valve connected to receive steam from the steam source and to discharge such steam to a power pressure stage of the turbine, said method comprising the steps of: (a) maintaining said bypass overload valve closed while controllably positioning said control valves to admit steam to the turbine to sustain a preselected power load; (b) increasingly opening said control valves with increasing load demand on the turbine until all valves of said plurality of control valves have reached a fully opened position; (c) fully opening said bypass overload valve while substantially simultaneously controllably positioning at least one of said control valves toward a closed position sufficient to offset steam flow through said bypass overload valve in excess of that required to sustain the turbine load; and (d) further increasing the power output of the turbine by controllably positioning said plurality of control valves toward said fully opened position.
Claim 2
Independent Claim
196 words
A method of operating a steam turbine delivering power to a connected load and adapted to receive steam from a steam generating source, the turbine having a plurality of control valves for controlling the admission of steam to higher pressure stages of the turbine and having a bypass overload valve connected to receive steam from the steam source and to discharge such steam to a power pressure stage of the turbine, said method comprising the steps of: (a) maintaining said bypass overload valve closed while controllably positioning said control valves to admit steam to the turbine to sustain a preselected power load; (b) increasingly opening said control valves with increasing load demand on the turbine until all valves of said plurality of control valves have reached a fully opened position; (c) fully opening said bypass overload valve while substantially simultaneously controllably positioning at least one of said control valves toward a closed position sufficient to offset steam flow through said bypass overload valve in excess of that required to sustain the turbine load; and (d) further increasing the power output of the turbine by controllably positioning said plurality of control valves toward said fully opened position.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein said bypass overload valve is manually caused to be opened and closed at an operator's discretion and said control valves are at all times automatically positioned by an automatic control system.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein said plurality of control valves are positioned substantially simultaneously.
Claim 5
Dependent Claim
16 words
The method of claim 2 wherein said plurality of control valves are positioned substantially in sequence.
Claim 6
Dependent Claim
42 words
The method of claim 1 wherein said bypass overload valve is automatically caused to be opened and closed in response to a signal indicative of turbine load and said control valves are at all times automatically positioned by an automatic control system.
Claim 7
Dependent Claim
15 words
The method of claim 5 wherein said plurality of control valves are positioned substantially simultaneously.
Claim 8
Dependent Claim
16 words
The method of claim 5 wherein said plurality of control valves are positioned substantially in sequence.
Claim 9
Dependent Claim
188 words
In combination with a steam turbine delivering power to a connected load and adapted to receive steam from a steam generating source, the turbine having a plurality of control valves for controlling the admission of steam to higher pressure stages of the turbine, apparatus for operating the turbine at elevated power loads comprising: (a) a bypass overload valve connected to receive steam from the steam source and to discharge such steam to a lower pressure stage of the turbine, said valve being operable only between a fully opened position and a fully closed position; and (b) means for operating said bypass overload valve between said open and closed positions, said means effective to maintain said bypass overload valve in a closed position while said control valves are controllably positioned to admit steam to the turbine to sustain a preselected power load, and said means effective to open said bypass overload valve when at least one of said control valves is substantially simultaneously controllably positioned toward a closed position sufficient to offset steam flow through said bypass overload valve in excess of that required to sustain the turbine load.
Claim 10
Dependent Claim
188 words
In combination with a steam turbine delivering power to a connected load and adapted to receive steam from a steam generating source, the turbine having a plurality of control valves for controlling the admission of steam to higher pressure stages of the turbine, apparatus for operating the turbine at elevated power loads comprising: (a) a bypass overload valve connected to receive steam from the steam source and to discharge such steam to a lower pressure stage of the turbine, said valve being operable only between a fully opened position and a fully closed position; and (b) means for operating said bypass overload valve between said open and closed positions, said means effective to maintain said bypass overload valve in a closed position while said control valves are controllably positioned to admit steam to the turbine to sustain a preselected power load, and said means effective to open said bypass overload valve when at least one of said control valves is substantially simultaneously controllably positioned toward a closed position sufficient to offset steam flow through said bypass overload valve in excess of that required to sustain the turbine load.
Claim 11
Dependent Claim
25 words
The combination of claim 8 wherein said means for operating said bypass overload valve is a manual means operable at the discretion of operating personnel.
Claim 12
Dependent Claim
28 words
The combination of claim 8 wherein said means for operating said bypass overload valve is an automatic means operative in response to a signal indicative of turbine load.
Claim 13
Dependent Claim
30 words
The combination of claim 8 wherein said bypass overload valve has a steam flow capacity of less than five percent of the flow capacity of said plurality of control valves.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |