Patent DK64792A successfully refreshed from Google Patents.
Patent US3602487A successfully refreshed from Google Patents.
US3602487A
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US
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Blast furnace stove control
Assignee: Jones and Laughlin Steel Corp
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Filing: 1969-11-10
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Granted: 1971-08-31
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Expires: 1989-11-10
Abstract
Abstract A system for controlling the operation of a blast furnace stove during its on-gas period, including means for controlling the enrichment of the combustion fuel used to heat the stove. Control is effected primarily by comparing a measured stove dome temperature to a stove heating-up or firing schedule, represented by the output of a function generator programmed according to a desired stove temperature-time relationship, and referencing differences in the temperatures to a natural gas flow control loop which controls the richness of the fuel mixture and thereby increases or decreases the heat input to the stove, as required.
Inventors
- 👤 Donald W Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:53
CPC Classifications
C; C21; C21B; C21B9/00; C21B9/10; C21B9/12; F; F23; F23N; F23N1/00; F23N1/005; F23N5/00; F23N5/003; F23N5/006; F23N2221/00; F23N2221/10; F23N2225/00; F23N2225/02; F23N2225/08; Y; Y02; Y02E; Y02E20/00; Y02E20/34; Y02P; Y02P10/00; Y02P10/10; Y02P10/143; Y02P10/32
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
229 words
A system for controlling the operation of a blast fuRnace stove during its on-gas period, said stove having a stove burner and associated blast furnace gas, natural gas and combustion air lines for conveying blast furnace gas, natural gas and combustion air respectively to the stove burner, said lines each including both means for measuring and providing an indication of the gas flow rate therein and means for controlling the action of a valve in the line in response to the difference between the measured gas flow rate and a gas flow rate to be established or if established to be maintained in the line including a. means for providing a representation of the temperature desired to be established in the stove dome as a function of time during the on-gas cycle, b. means connected to means (a) for comparing the actual stove dome temperature and the desired stove dome temperature and calling for a natural gas flow rate to be established or if established to be maintained to the burner as a function of the magnitude of the difference between the temperatures and c. means for calling for a combustion airflow rate to be established or if established to be maintained to the burner including ratio means for calling for a combustion airflow rate which is a preselected constant multiple of the measured blast furnace gas flow rate.
Claim 2
Independent Claim
229 words
A system for controlling the operation of a blast fuRnace stove during its on-gas period, said stove having a stove burner and associated blast furnace gas, natural gas and combustion air lines for conveying blast furnace gas, natural gas and combustion air respectively to the stove burner, said lines each including both means for measuring and providing an indication of the gas flow rate therein and means for controlling the action of a valve in the line in response to the difference between the measured gas flow rate and a gas flow rate to be established or if established to be maintained in the line including a. means for providing a representation of the temperature desired to be established in the stove dome as a function of time during the on-gas cycle, b. means connected to means (a) for comparing the actual stove dome temperature and the desired stove dome temperature and calling for a natural gas flow rate to be established or if established to be maintained to the burner as a function of the magnitude of the difference between the temperatures and c. means for calling for a combustion airflow rate to be established or if established to be maintained to the burner including ratio means for calling for a combustion airflow rate which is a preselected constant multiple of the measured blast furnace gas flow rate.
Claim 3
Dependent Claim
104 words
The system of claim 1 wherein the means for calling for a combustion airflow rate to be established or if established to be maintained to the burner further includes oxygen loop means for calling for an increase in the combustion airflow rate over that called for by the ratio means when the oxygen gas content of the gases issuing from the stove exhaust stack is below a preselected level and a decrease in the combustion airflow rate below that called for by the ratio means when the oxygen gas content of the gases issuing from the stove exhaust stack is above said preselected level.
Claim 4
Dependent Claim
71 words
The system of claim 2 wherein the means for calling for a combustion airflow rate to be established or if established to be maintained to the burner further includes means calling for an increase in the combustion airflow rate over that called for by the ratio means and the oxygen loop means when the natural gas flow is zero and the measured dome temperature is greater than a predetermined maximum temperature.
Claim 5
Dependent Claim
68 words
The system of claim 2 wherein the oxygen loop means includes means for keeping the magnitude of the increase or decrease in the airflow rate called for constant for intermittent time periods in order to compensate for the time which is required for changes made in the airflow rate to be manifested at a means for measuring the oxygen content of the gases issuing from the stove stack.
Claim 6
Dependent Claim
38 words
The system of claim 1 including means for keeping the natural gas flow rate called for from exceeding a predetermined maximum which is based on the blast furnace gas flow rate desired to be maintained to the burner.
Claim 7
Dependent Claim
31 words
The system of claim 5 including means for keeping the natural gas flow rate called for below a preselected percentage of the measured blast furnace gas flow rate to the burner.
Claim 8
Dependent Claim
97 words
The system of claim 6 wherein the means for calling for a combustion airflow rate to be established or if established to be maintained to the burner further includes oxygen loop means for calling for a greater airflow rate than called for by the ratio means when the oxygen gas content of the gases issuing from the stove exhaust stack is below a preselected level and a lesser airflow rate than that called for by the ratio means when the oxygen gas content of the gas issuing from the stove exhaust stack is above said selected level.
Claim 9
Dependent Claim
68 words
The system of claim 7 wherein the means for calling for a combustion airflow rate to be established or if established to be maintained to the burner further includes means calling for a greater airflow rate than that called for by the ratio means and the oxygen loop means when the natural gas flow is zero and the measured dome temperature is greater than a predetermined maximum temperaturE.
Claim 10
Dependent Claim
63 words
The system of claim 7 wherein the oxygen loop means includes means for keeping the greater or lesser flow rate called for constant for intermittent time periods in order to compensate for the time which is required for changes made in the airflow rate to be manifested at a means for measuring the oxygen content of the gases issuing from the stove stack.
Claim 11
Independent Claim
270 words
A system for controlling the operation of a blast furnace stove during its on-gas period, said stove having a stove burner and associated blast furnace gas, natural gas and combustion air respectively to the stove burner, said lines each including both means for measuring and providing an indication of the gas flow rate therein and means for controlling the action of a valve in the line in response to the difference between the measured gas flow rate and a gas flow rate to be established or if established to be maintained in the line including a. temperature profile function generator means for providing an electrical output representative of the temperature desired to be established in the stove dome as a function of time during the on-gas cycle, b. sensing means for measuring the stove dome temperature and developing an electrical signal measurably responsive thereto, c. natural gas flow proportional controller means for developing an output signal measurably responsive to the difference between the signals of the temperature profile function generator means and the sensing means, said signal being representative of a natural gas flow rate to be established or if established to be maintained to the burner as a function of the magnitude of the difference between the desired stove dome temperature and actual stove dome temperature, d. means for developing an electrical signal representative of a combustion airflow rate to be established or if established to be maintained to the burner including ratio means for developing an electrical signal representative of a combustion airflow rate which is a preselected constant multiple of the measured blast furnace gas flow rate.
Claim 12
Independent Claim
270 words
A system for controlling the operation of a blast furnace stove during its on-gas period, said stove having a stove burner and associated blast furnace gas, natural gas and combustion air respectively to the stove burner, said lines each including both means for measuring and providing an indication of the gas flow rate therein and means for controlling the action of a valve in the line in response to the difference between the measured gas flow rate and a gas flow rate to be established or if established to be maintained in the line including a. temperature profile function generator means for providing an electrical output representative of the temperature desired to be established in the stove dome as a function of time during the on-gas cycle, b. sensing means for measuring the stove dome temperature and developing an electrical signal measurably responsive thereto, c. natural gas flow proportional controller means for developing an output signal measurably responsive to the difference between the signals of the temperature profile function generator means and the sensing means, said signal being representative of a natural gas flow rate to be established or if established to be maintained to the burner as a function of the magnitude of the difference between the desired stove dome temperature and actual stove dome temperature, d. means for developing an electrical signal representative of a combustion airflow rate to be established or if established to be maintained to the burner including ratio means for developing an electrical signal representative of a combustion airflow rate which is a preselected constant multiple of the measured blast furnace gas flow rate.
Claim 13
Dependent Claim
173 words
The system of claim 10 wherein the means for developing an electrical signal representative of a combustion airflow rate to be established or if established to be maintained to the burner further includes oxygen analyzer means for developing an electrical signal representative of the oxygen gas content of the gases issuing from the stove stack and a combustion airflow proportional controller means for developing, in response to the electrical signal developed by the oxygen analyzer means and an electrical signal representative of an oxygen gas content desired to be maintained in the exhaust gases issuing from the stove stack, an electrical signal representative of an increase in the combustion airflow rate over that called for by the ratio means when the oxygen gas content of the gases issuing from the stove exhaust stack is below the desired level and a decrease in the combustion airflow rate below that called for by the ratio means when the oxygen gas content of the gases issuing from the stove exhaust stack is above said desired level.
Claim 14
Dependent Claim
105 words
The system of claim 11 wherein the means for developing an electrical signal representative of a combustion airflow rate to be established or if established to be maintained to the burner further includes proportional controller means for developing, in response to the electrical signal developed by the temperature-sensing means and an electrical signal representative of a preselected maximum dome temperature, an electrical signal representative of an increase in the combustion airflow rate over that called for by the ratio means and the oxygen loop means when the natural gas flow is zero and the measured dome temperature is greater than the preselected maximum dome temperature.
Claim 15
Dependent Claim
89 words
The system of claim 12 including time-lag compensator means for alternately integrating the electrical error signal developed by the combustion airflow proportional controller means during a firSt period of time while developing an electrical output signal during that period of time as a function of the integration and maintaining the integrated signal developed at the end of the first period of time constant for a following second period of time whereby to allow for changes made in the combustion airflow rate to be manifested at the oxygen analyzer means.
Claim 16
Dependent Claim
71 words
The system of claim 13 including natural gas set point means for developing an electrical signal in response to the electrical signal developed by the natural gas flow proportional controller means and for keeping the electrical signal which it develops from exceeding a predetermined maximum which is representative of a predetermined maximum natural gas flow rate based on the blast furnace gas flow rate desired to be maintained to the burner.
Claim 17
Dependent Claim
56 words
The system of claim 14 including modifier means for developing an electrical signal in response to the electrical signal developed by the natural gas set point means and for keeping the electrical signal which it develops below a value representative of a maximum preselected percentage of the measured blast furnace gas flow rate to the burner.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-30 | 1975-03-01 | 1975-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-30 | 1979-03-01 | 1979-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-30 | 1983-03-01 | 1983-08-31 | $7700.00 | Window Closed / Lapsed |