US3780705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of controlling the feed of forced circulation steam generators
Assignee: Sulzer AG
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Filing: 1972-09-25
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Granted: 1973-12-25
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Expires: 1992-09-25
Abstract
Abstract The rate of feedwater flow is controlled in a first load range by the level of water in the separator while in a higher load range the rate is controlled by the steam temperature. Signals are produced which are compared with preset values and are integrated so as to produce a negative control signal in one case and a positive control signal in the other case. Only one of these control signals is superimposed on a base signal only when the generator is in a respective load range so as to produce a command signal for adjusting the feed controller of the feed valve.
Inventors
- 👤 Vivy D De
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:14
CPC Classifications
F; F22; F22B; F22B35/00; F22B35/06; F22B35/14; F22B35/10; F22B35/101
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
162 words
A method of controlling a rate of feed of water in a forced circulation steam generator comprising the steps of feeding a flow of feedwater to the steam generator; producing a first contrOl signal in response to a first controlled condition acting predominantly on the flow of feedwater in a first load range; producing a second control signal in response to a second controlled condition acting predominantly on the flow of feedwater in a second load range; producing a predetermined base signal; and generating a command signal to control the flow of feedwater in said first load range from a superposition of said base signal with only said first control signal and only when said first control signal is of a sense to reduce said base signal and in said second load range from a superposition of said base signal with only said second control signal and only when said second control signal is of a sense to increase said base signal.
Claim 2
Independent Claim
162 words
A method of controlling a rate of feed of water in a forced circulation steam generator comprising the steps of feeding a flow of feedwater to the steam generator; producing a first contrOl signal in response to a first controlled condition acting predominantly on the flow of feedwater in a first load range; producing a second control signal in response to a second controlled condition acting predominantly on the flow of feedwater in a second load range; producing a predetermined base signal; and generating a command signal to control the flow of feedwater in said first load range from a superposition of said base signal with only said first control signal and only when said first control signal is of a sense to reduce said base signal and in said second load range from a superposition of said base signal with only said second control signal and only when said second control signal is of a sense to increase said base signal.
Claim 3
Dependent Claim
56 words
A method as set forth in claim 1 wherein said first controlled condition is the water level in a water-steam separator in the steam generator in the flow path of the feedwater and said second controlled condition is the steam temperature of the steam generated from the feedwater downstream of a superheater in the steam generator.
Claim 4
Dependent Claim
39 words
A method as set forth in claim 1 wherein said base signal corresponds to a feedwater flow rate prevailing in a transition zone between the predominance of said first controlled condition and the predominance of the second controlled condition.
Claim 5
Dependent Claim
52 words
A method as set forth in claim 1 wherein said first control signal is formed by a separate controller having integral action from a signal responsive to said first controlled condition and which further comprises the step of blocking integration by the controller as soon as said first control signal becomes negative.
Claim 6
Dependent Claim
52 words
A method as set forth in claim 1 wherein said second control signal is formed by a separate controller having integral action from a signal responsive to said second controlled condition and which further comprises the step of blocking integration by the controller as soon as said second control signal becomes negative.
Claim 7
Dependent Claim
92 words
A method as set forth in claim 5 wherein said first control signal is formed by a second separate controller having integral action from a signal responsive to said first controlled condition and which further comprises the steps of blocking integration by the second controller as soon as said first control signal becomes negative, of blocking integration by one of the controllers when the signals supplied to the controllers are both positive and of blocking integration by the other of the controllers when the signals supplied to the controllers are both negative.
Claim 8
Dependent Claim
58 words
A method as set forth in claim 3 wherein the steam generator is a forced through-flow steam generator with forced circulation in a limited load range and having an evaporator, and wherein said base signal has a value sufficiently high to produce a feedwater rate sufficient to cool the evaporator at the top of said limited load range.
Claim 9
Dependent Claim
198 words
In combination with a steam generator having a feed controller for controlling the rate of feedwater flow to an evaporator, a water separator downstream of said evaporator and at least one superheater downstream of said water separator; means for controlling said feed controller to control the rate of flow of the feedwater, said means including a water-level measuring means connected to said separator to produce a first control signal in response to the level of water in said separator, a steam temperature measuring means downstream of said superheater to produce a second control signal in response to the temperature of the steam thereat, a base signal transmitter for emitting a predetermined base signal, and means for super-imposing said base signal with only said first control signal in a first load range when said first control signal is negative relative to said base signal and with only said second control signal in a second load range when said second control signal is positive relative to said base signal for producing a command signal, said latter means being connected to said feed controller to deLiver said command signal thereto for adjustment of the rate of feedwater flow in response thereto.
Claim 10
Dependent Claim
198 words
In combination with a steam generator having a feed controller for controlling the rate of feedwater flow to an evaporator, a water separator downstream of said evaporator and at least one superheater downstream of said water separator; means for controlling said feed controller to control the rate of flow of the feedwater, said means including a water-level measuring means connected to said separator to produce a first control signal in response to the level of water in said separator, a steam temperature measuring means downstream of said superheater to produce a second control signal in response to the temperature of the steam thereat, a base signal transmitter for emitting a predetermined base signal, and means for super-imposing said base signal with only said first control signal in a first load range when said first control signal is negative relative to said base signal and with only said second control signal in a second load range when said second control signal is positive relative to said base signal for producing a command signal, said latter means being connected to said feed controller to deLiver said command signal thereto for adjustment of the rate of feedwater flow in response thereto.
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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |