US3759659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for cement kiln control
Assignee: Leeds and Northrup Co
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Filing: 1972-06-08
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Granted: 1973-09-18
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Expires: 1992-06-08
Abstract
Abstract A control system for controlling the firing rate in a rotary cement kiln so as to maintain the temperature just ahead of the chain section at a predetermined set point. The control system includes both proportional and integral control and is adaptive in that the reset rate of the controller is increased when the temperature deviation exceeds a predetermined amount. In addition the overall gain of the control system is modified so that the gain is changed to a lower value when a temperature measurement in the mid-kiln region exceeds a certain high value with the gain being changed to a higher value when that mid-kiln temperature is below a predetermined minimum value. Means are provided to compensate for the discontinuity in the proportional control action when the mid-kiln temperature causes a change in the controller gain.
Inventors
- 👤 T Bay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:34
CPC Classifications
G; G05; G05B; G05B13/00; G05B13/02; G05B13/0205; G05B13/024; F; F27; F27B; F27B7/00; F27B7/20; F27B7/34; F27B7/42
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
52 words
A control system for controlling the temperature of the material being processed in a rotary cement kiln comprising: means for measuring the temperature in the prechain area of the kiln, and means for controlling the firing rate of the kiln to tend to maintain said prechain temperature at a predetermined set point.
Claim 2
Dependent Claim
52 words
A control system for controlling the temperature of the material being processed in a rotary cement kiln comprising: means for measuring the temperature in the prechain area of the kiln, and means for controlling the firing rate of the kiln to tend to maintain said prechain temperature at a predetermined set point.
Claim 3
Dependent Claim
28 words
A control system as set forth in claim 1 in which the controlling means includes: means for providing proportional control action, and means for providing reset control action.
Claim 4
Dependent Claim
35 words
A control system as set forth in claim 2 in which the reset rate of the controlling means is increased when the prechain temperature deviates from its set point by more than a predetermined amount.
Claim 5
Dependent Claim
98 words
A control system as set forth in claim 2 which includes: means for measuring a temperature representing the temperature of the material being processed as it passes through the mid-kiln region, and means operable to change the effective proportional gain of the controlling means to a lower value when the mid-kiln temperature exceeds a certain high value and to change said gain to a higher value when said mid-kiln temperature is below a predetermined minimum value with the effective proportional gain being at a predetermined normal value when said mid-kiln temperature is between said low and high values.
Claim 6
Independent Claim
50 words
A method for automatically controlling the temperature of the material being processed in a rotary cement kiln comprising: automatically measuring the temperature in the prechain area of the kiln, and automatically controlling the firing rate of the kiln to tend to maintain said prechain temperature at a predetermined set point.
Claim 7
Independent Claim
50 words
A method for automatically controlling the temperature of the material being processed in a rotary cement kiln comprising: automatically measuring the temperature in the prechain area of the kiln, and automatically controlling the firing rate of the kiln to tend to maintain said prechain temperature at a predetermined set point.
Claim 8
Dependent Claim
20 words
A method set forth in claim 5 in which the automatic control includes proportional control action and reset control action.
Claim 9
Dependent Claim
35 words
A method as set forth in claim 6 in which the reset rate of the reset control action is increased when the prechain temperature deviates from its set point by more than a predetermined amount.
Claim 10
Dependent Claim
97 words
A method as set forth in claim 6 which includes the steps of: automatically measuring a temperature representing the temperature of the material being processed as it passes through the mid-kiln region, and automatically changing the effective proportional gain of the controlling means to a lower value when the mid-kiln temperature exceeds a certain high value and changing said gain to a higher value when said mid-kiln temperature is below a predetermined minimum value with the effective proportional gain being maintained at a predetermined normal value when said mid-kiln temperature is between said low and high values.
References Cited (Backward Citations)
US3578299A
Cited
US3610596A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |