US3709626A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital analog electrohydraulic turbine control system
Assignee: General Electric Co
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Filing: 1971-09-16
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Granted: 1973-01-09
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Expires: 1991-09-16
Abstract
Abstract An electrohydraulic control system for a steam turbine has steam valve actuators with analog valve position set points or reference values supplied by a main control loop with a digital computer. The digital computer performs complex calculations to obtain the valve position set points in accordance with operating parameters of the steam turbine and desired operational modes. A standby analog control loop furnishes a simple speed and load control function in the event of loss of digital signals. When in digital computer mode, the analog speed loop provides a safety backup function through a ''''dead band'''' which provides valve closing signals upon excessive speed. In the analog or standby mode, a load reference signal representing the most recent load set point is supplied to the analog control loop from a memory unit constantly updated by the digital computer.
Inventors
- 👤 M Eggenberger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:37
CPC Classifications
G; G05; G05B; G05B9/00; G05B9/02; G05B9/03; F; F01; F01D; F01D17/00; F01D17/20; F01D17/22; F01D17/24; F01D21/00; F01D21/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
147 words
In a control system for a prime mover having valve means controlling the supply of energy to the prime mover, the combination of: at least one inner closed loop arranged to position said valve means in response to an analog valve position reference signal, a first outer loop including a digital computer responsive to the position of said valve means and also to selected operating parameters of said prime mover, a second outer loop including analog control means responsive to prime mover speed and connected to supply a second signal to said inner loop through a separate signal path, said signal path including ''''dead band'''' means arranged to provide an analog valve closing signal only above a first selected overspeed, whereby said second loop serves as a standby control for said first loop and is operative to commence closing said valve means above said first selected speed.
Claim 2
Dependent Claim
147 words
In a control system for a prime mover having valve means controlling the supply of energy to the prime mover, the combination of: at least one inner closed loop arranged to position said valve means in response to an analog valve position reference signal, a first outer loop including a digital computer responsive to the position of said valve means and also to selected operating parameters of said prime mover, a second outer loop including analog control means responsive to prime mover speed and connected to supply a second signal to said inner loop through a separate signal path, said signal path including ''''dead band'''' means arranged to provide an analog valve closing signal only above a first selected overspeed, whereby said second loop serves as a standby control for said first loop and is operative to commence closing said valve means above said first selected speed.
Claim 3
Dependent Claim
37 words
The combination according to claim 1, wherein said dead band means is arranged to disable said first outer loop upon reaching a second selected overspeed, whereby the prime mover is controlled only by said second outer loop.
Claim 4
Dependent Claim
70 words
The combination according to claim 1, wherein said dead band means comprises a pair of operational amplifiers connected through diodes to a common gating bus, and wherein one of said amplifiers is connected to provide a valve closing signal above a selected overspeed bias signal, and wherein the other of said amplifiers is connected to supply a zero signal so as to suppress valve opening signals on said gating bus.
Claim 5
Dependent Claim
218 words
In a control system for a prime mover having valve means controlling the supply of energy to the prime mover, the combination of: at least one inner closed loop arranged to position said valve means in response to an analog valve position reference signal, a first outer loop including a digital computer responsive to the position of said valve means and to selected operating parameters of said prime mover, said first outer loop further connected through first switching means to supply a signal to said inner loop, a second outer loop including analog control means responsive to prime mover speed and connected to supply a signal to said inner loop through first and second alternate signal paths controlled by second switching means, said first signal path having dead band means to provide an analog valve closing signal only above a selected over-speed, and switching relay means connected to said first and second switching means to supply said valve position signal both from said first outer loop and from said first alternate signal path in the second outer loop when the control system is in a primary mode of operation and to supply said valve position signal through said second alternate signal path of the second outer loop when the control system is in a standby mode of operation.
Claim 6
Dependent Claim
218 words
In a control system for a prime mover having valve means controlling the supply of energy to the prime mover, the combination of: at least one inner closed loop arranged to position said valve means in response to an analog valve position reference signal, a first outer loop including a digital computer responsive to the position of said valve means and to selected operating parameters of said prime mover, said first outer loop further connected through first switching means to supply a signal to said inner loop, a second outer loop including analog control means responsive to prime mover speed and connected to supply a signal to said inner loop through first and second alternate signal paths controlled by second switching means, said first signal path having dead band means to provide an analog valve closing signal only above a selected over-speed, and switching relay means connected to said first and second switching means to supply said valve position signal both from said first outer loop and from said first alternate signal path in the second outer loop when the control system is in a primary mode of operation and to supply said valve position signal through said second alternate signal path of the second outer loop when the control system is in a standby mode of operation.
Claim 7
Dependent Claim
76 words
The combination according to claim 4 and further including a load reference memory device adapted to receive a load reference signal from said digital computer and to generate an analog reference signal corresponding to the last-received digital load reference signal, and third switching means operated by said switching relay means to connect the analog load reference signal to the second outer loop second alternate path when the control system is in the standby mode of operation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |