US3611039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for preventing overspeed of elastic fluid turbine driven generators
Assignee: Toshiba Corp
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Filing: 1968-11-12
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Granted: 1971-10-05
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Expires: 1988-11-12
Abstract
Abstract An apparatus for preventing overspeed operation of a turbine in response to the output of a turbine-driven generator comprises a control valve for controlling the motive fluid supply to the turbine and an electric control system. The electric control system includes a first switch responsive to the generator output above a first value and a second switch responsive to the generator output below a second value within a predetermined time period and cooperative with the first switch to provide a control signal to accordingly actuate the control valve.
Inventors
- 👤 Tetsuzo Sakamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:17
CPC Classifications
F; F01; F01D; F01D21/00; F01D21/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
406 words
In an elastic fluid turbine driven generator system having a turbine-driven generator, a turbine rotationally driven by motive fluiD and connected to rotationally drive said generator, valve means including a control valve for controlling the flow of motive fluid supplied to said turbine, and speed-responsive means to control said valve means to maintain the speed of said turbine at a predetermined constant value, an improvement in an apparatus for preventing overspeed of said turbine generator comprising: a load detector operative to determine whether the electrical load of said generator is above a first predetermined value or below a second predetermined value which is lower than said first value, said first and second values being selected such that upon quick reduction in the electrical load of said generator from said first value to said second value said generator reaches an undesirable overspeed; means to detect the extent of opening of said control valve for determining whether the extent of opening of said control valve is larger than a predetermined extent of opening which is substantially equal to the extent of opening of said control valve when an electrical load substantially equal to said first value is applied to said generator under normal condition; memory means to store for a predetermined interval of time the fact that said load detector has detected the presence of a load exceeding said first value, when the electrical load is decreased from a value exceeding said first value to a value less than the same; first means for providing a first signal when said load detector has detected the fact that the electrical load has a value less than said second value during an interval during which said memory means is storing the presence of a load of more than said first value; second means for providing a second signal when said means for detecting the extent of opening of said control valve detects the fact that said extent is more than said predetermined extent of opening and when said load detector detects the fact that the electrical load is less than said second value; means to generate a command signal for a predetermined interval to cause rapid closure of said control valve in response to either one or both of said first and second signals and means responsive to said command signals to rapidly close said control valve in preference to the control by said speed-responsive means thus preventing undesirable overspeed.
Claim 2
Dependent Claim
406 words
In an elastic fluid turbine driven generator system having a turbine-driven generator, a turbine rotationally driven by motive fluiD and connected to rotationally drive said generator, valve means including a control valve for controlling the flow of motive fluid supplied to said turbine, and speed-responsive means to control said valve means to maintain the speed of said turbine at a predetermined constant value, an improvement in an apparatus for preventing overspeed of said turbine generator comprising: a load detector operative to determine whether the electrical load of said generator is above a first predetermined value or below a second predetermined value which is lower than said first value, said first and second values being selected such that upon quick reduction in the electrical load of said generator from said first value to said second value said generator reaches an undesirable overspeed; means to detect the extent of opening of said control valve for determining whether the extent of opening of said control valve is larger than a predetermined extent of opening which is substantially equal to the extent of opening of said control valve when an electrical load substantially equal to said first value is applied to said generator under normal condition; memory means to store for a predetermined interval of time the fact that said load detector has detected the presence of a load exceeding said first value, when the electrical load is decreased from a value exceeding said first value to a value less than the same; first means for providing a first signal when said load detector has detected the fact that the electrical load has a value less than said second value during an interval during which said memory means is storing the presence of a load of more than said first value; second means for providing a second signal when said means for detecting the extent of opening of said control valve detects the fact that said extent is more than said predetermined extent of opening and when said load detector detects the fact that the electrical load is less than said second value; means to generate a command signal for a predetermined interval to cause rapid closure of said control valve in response to either one or both of said first and second signals and means responsive to said command signals to rapidly close said control valve in preference to the control by said speed-responsive means thus preventing undesirable overspeed.
Claim 3
Dependent Claim
313 words
A steam turbine arrangement for driving a generator supplying electric power to an electric load, said steam turbine arrangement including valve means to control steam applied to said turbine, and a speed governor which controls said valve means through a first fluid pressure servomechanism comprising a pilot valve and a hydraulic relay responsive to the fluid pressure from said pilot valve to actuate said valve means, an improvement in an apparatus for preventing overspeed of said turbine comprising; means including a wattmeter for detecting the effective electric load of said generator to provide a first output when said load is above a first predetermined value and a second output when said load is less than a second predetermined value, said first and second values being set such that said governor reaches an undesirable overspeed when said load rapidly decreases from a value above said first value to a value less than said second value; means to detect valve opening of said valve means to provide a third output when the extent of opening of said valve means is above a predetermined extent which is substantially equal to the extent of opening of said valve means when said electric load is nearly equal to said first valve under normal steam conditions; a memory device responsive to said first output to provide a fourth output having an off-delay characteristic; means to provide a fifth output when said second and fourth outputs exists simultaneously; means to provide a sixth output when said second and third outputs exist simultaneously; means responsive to either one of said fifth and sixth outputs to provide for a predetermined time interval a closing signal to Effect rapid closing of said valve means; and a second fluid-operated servomechanism responsive to said closing signal to cause said first servomechanism to override said governor to rapidly close said valve means thus preventing undesirable overspeed.
Claim 4
Dependent Claim
313 words
A steam turbine arrangement for driving a generator supplying electric power to an electric load, said steam turbine arrangement including valve means to control steam applied to said turbine, and a speed governor which controls said valve means through a first fluid pressure servomechanism comprising a pilot valve and a hydraulic relay responsive to the fluid pressure from said pilot valve to actuate said valve means, an improvement in an apparatus for preventing overspeed of said turbine comprising; means including a wattmeter for detecting the effective electric load of said generator to provide a first output when said load is above a first predetermined value and a second output when said load is less than a second predetermined value, said first and second values being set such that said governor reaches an undesirable overspeed when said load rapidly decreases from a value above said first value to a value less than said second value; means to detect valve opening of said valve means to provide a third output when the extent of opening of said valve means is above a predetermined extent which is substantially equal to the extent of opening of said valve means when said electric load is nearly equal to said first valve under normal steam conditions; a memory device responsive to said first output to provide a fourth output having an off-delay characteristic; means to provide a fifth output when said second and fourth outputs exists simultaneously; means to provide a sixth output when said second and third outputs exist simultaneously; means responsive to either one of said fifth and sixth outputs to provide for a predetermined time interval a closing signal to Effect rapid closing of said valve means; and a second fluid-operated servomechanism responsive to said closing signal to cause said first servomechanism to override said governor to rapidly close said valve means thus preventing undesirable overspeed.
Claim 5
Dependent Claim
50 words
The apparatus as claimed in claim 2, wherein said second fluid-operated servomechanism is included in a mechanism transmitting a signal from said governor to said pilot valve and comprises a cylinder connected to said transmitting mechanism and a spring-biased land contained in said cylinder and connected to said pilot valve.
Claim 6
Dependent Claim
222 words
In combination: a generator rotationally driven to develop an electrical output and having a predetermined overspeed condition; a fluid-driven turbine connected to said generator operative in response to motive fluid applied thereto to rotationally drive said generator; valve means for controlling the supply of motive fluid to said turbine in accordance with the rotational speed thereof; detecting means for detecting when the electrical output of said generator decreases from a first predetermined value to a second predetermined value within a time period T1 representative of an overspeed condition of said generator and providing a corresponding output signal, said detecting means comprising first normally open electric switching means operable to a closed position whenever said generator output exceeds said first predetermined value and for said time period T1 after said output falls below said first predetermined value, second normally open electric switching means operable to a closed position whenever said generator output falls below said second predetermined value for said time period T2, and electric circuit means including said first and second switching means for providing said output signal whenever a portion of said time period T1 coincides with a portion of said time period T2; and means responsive to said output signal for overriding said valve means to effect a reduction in speed of said turbine for a predetermined time period T2.
Claim 7
Dependent Claim
222 words
In combination: a generator rotationally driven to develop an electrical output and having a predetermined overspeed condition; a fluid-driven turbine connected to said generator operative in response to motive fluid applied thereto to rotationally drive said generator; valve means for controlling the supply of motive fluid to said turbine in accordance with the rotational speed thereof; detecting means for detecting when the electrical output of said generator decreases from a first predetermined value to a second predetermined value within a time period T1 representative of an overspeed condition of said generator and providing a corresponding output signal, said detecting means comprising first normally open electric switching means operable to a closed position whenever said generator output exceeds said first predetermined value and for said time period T1 after said output falls below said first predetermined value, second normally open electric switching means operable to a closed position whenever said generator output falls below said second predetermined value for said time period T2, and electric circuit means including said first and second switching means for providing said output signal whenever a portion of said time period T1 coincides with a portion of said time period T2; and means responsive to said output signal for overriding said valve means to effect a reduction in speed of said turbine for a predetermined time period T2.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |