US3913329A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Turbine overspeed control system
Assignee: General Electric Co
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Filing: 1974-10-04
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Granted: 1975-10-21
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Expires: 1994-10-04
Abstract
Abstract Steam flow to a turbine is reduced by partially closing intercept control valves to reduce turbine speed to a reference speed after sudden increases above this speed caused by sudden decreases in turbine load. Circuitry for developing a command signal for closing the valves in response to a difference between the reference speed and the actual speed of the turbine is provided. The command signal magnitude is varied to cause rapid closing motion of the valves during that portion of valve movement having little effect on steam flow and less rapid closing motion during that portion of valve movement having substantial effect on steam flow, thereby compensating for a nonlinear relationship between valve movement and change in steam flow.
Inventors
- 👤 David Manuel Priluck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:31
CPC Classifications
F; F01; F01K; F01K7/00; F01K7/16; F01K7/22; F01K7/24; F01D; F01D21/00; F01D21/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
152 words
In an overspeed control system for steam turbines of the type wherein steam flow to the turbine is reduced by a valve to decrease speed to a reference speed after sudden undesired increases above this reference speed, the improvement comprising: a. a circuit for developing a command signal for controlling the position of the valve in response to a difference between the reference speed and the actual speed of the turbine; b. said circuit including means for developing a command signal which initially increases at a rapid rate causing rapid closing motion of the valve during that portion of valve movement having little effect on steam flow and later increases at a less rapid rate causing less rapid closing motion of the valve during that portion of valve movement having substantial effect on steam flow, whereby said circuit compensates for a nonlinear relationship between valve movement and change in the steam flow.
Claim 2
Dependent Claim
152 words
In an overspeed control system for steam turbines of the type wherein steam flow to the turbine is reduced by a valve to decrease speed to a reference speed after sudden undesired increases above this reference speed, the improvement comprising: a. a circuit for developing a command signal for controlling the position of the valve in response to a difference between the reference speed and the actual speed of the turbine; b. said circuit including means for developing a command signal which initially increases at a rapid rate causing rapid closing motion of the valve during that portion of valve movement having little effect on steam flow and later increases at a less rapid rate causing less rapid closing motion of the valve during that portion of valve movement having substantial effect on steam flow, whereby said circuit compensates for a nonlinear relationship between valve movement and change in the steam flow.
Claim 3
Dependent Claim
121 words
A system as in claim 1 wherein said circuit comprises: a. a first amplifier functioning at speeds above the reference speed to develop a first electrical output signal varying at a rapid rate with respect to turbine speed; b. a second amplifier functioning at speeds above a predetermined overspeed to develop a second electrical output signal varying at a less rapid rate than the first output signal with respect to turbine speed; c. means for applying the second output signal to said first amplifier causing a reduction in the rate of increase of the signal at the output of said first amplifier at speeds above the predetermined overspeed; and d. the output signal from said first amplifier constituting said command signal.
Claim 4
Dependent Claim
64 words
A system as in claim 2 further comprising: a. A third amplifier electrically connected to the output of said first amplifier acting to prevent the command signal from rising above a predetermined upper voltage limit; and b. a fourth amplifier also electrically connected to the output of said first amplifier acting to prevent the command signal from falling below a predetermined lower voltage limit.
Claim 5
Dependent Claim
27 words
A system as in claim 3 further comprising a fifth amplifier acting to prevent the second amplifer output signal from falling below a predetermined lower voltage limit.
Claim 6
Dependent Claim
41 words
A system as in claim 2 including means for providing an input to said first amplifier utilized for periodic application of a test signal causing development of an output signal from said first amplifier resulting in partial closure of the valve.
References Cited (Backward Citations)
US3811279A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |