US4177950A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control for a power plant coal mill pulverizer having feedforward damper positioning
Assignee: Westinghouse Electric Corp
•
Filing: 1978-02-16
•
Granted: 1979-12-11
•
Expires: 1998-02-16
Abstract
Abstract Power plant boiler fuel demand is transmitted as a coal feeder speed demand to a coal pulverizer control. A speed controller operates the feeder in accordance with the speed demand, and a position controller for a hot coal transport air damper positions the hot air damper to hold the mill outlet temperature to a setpoint value and to increase or decrease damper position in accordance with a feedforward signal representing the feeding speed demand. A position controller for a cold air damper regulates the total primary air flow to a value needed for safe and smooth transport of the pulverized coal to the boiler burners, and it accordingly acts as a process trim on the feedforward control applied by the hot damper controller.
Inventors
- 👤 William J. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:32
CPC Classifications
F; F23; F23K; F23K1/00; F23K3/00; F23K3/02; F23N; F23N1/00; F23N1/02; F23N5/00; F23N5/18; F23K2201/00; F23K2201/10; F23N2239/00; F23N2239/02
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
178 words
A control for an electric power plant pulverizer mill having a variable speed feeder and hot and cold air ducts supplying primary air flow through said pulverizer under the control of respective hot and cold air dampers, said control comprising means for sensing the temperature of the mill outlet flow, means for sensing the primary air flow, means for generating a feeder speed demand, means for operating the feeder in accordance with the feeder speed demand, means for positioning the hot damper in accordance with a hot damper position demand, means for positioning the cold damper in accordance with a cold damper position demand, means for generating the damper position demands in response to said flow and temperature sensing means to control total primary air flow in accordance with a predetermined function and to control the mill outlet temperature in accordance with another predetermined function, and means for applying the feeder speed demand to said damper position demand generating means to produce anticipatory movement of at least one of the dampers in response to feeder speed demand changes.
Claim 2
Dependent Claim
178 words
A control for an electric power plant pulverizer mill having a variable speed feeder and hot and cold air ducts supplying primary air flow through said pulverizer under the control of respective hot and cold air dampers, said control comprising means for sensing the temperature of the mill outlet flow, means for sensing the primary air flow, means for generating a feeder speed demand, means for operating the feeder in accordance with the feeder speed demand, means for positioning the hot damper in accordance with a hot damper position demand, means for positioning the cold damper in accordance with a cold damper position demand, means for generating the damper position demands in response to said flow and temperature sensing means to control total primary air flow in accordance with a predetermined function and to control the mill outlet temperature in accordance with another predetermined function, and means for applying the feeder speed demand to said damper position demand generating means to produce anticipatory movement of at least one of the dampers in response to feeder speed demand changes.
Claim 3
Dependent Claim
76 words
A control as set forth in claim 1 wherein the total primary air flow and the mill outlet temperature are controlled to respective setpoint values and wherein said damper position demand generating means applies a position demand to said hot damper positioning means on the basis of feeder speed demand and further applies a position demand to said cold damper positioning means on the basis of the flow setpoint and an output from said flow sensor.
Claim 4
Dependent Claim
60 words
A control as set forth in claim 2 wherein means are provided for generating a mill outlet temperature setpoint, controller means are provided for generating a temperature correction based on the actual and setpoint temperatures, and said damper position demand generating means generates the hot damper position demand as a function of the feeder speed demand and the temperature correction.
Claim 5
Dependent Claim
67 words
A control as set forth in claim 1 wherein the total primary air flow and the mill outlet temperature are controlled to respective setpoint values and wherein said damper position demand generating means applies a position demand based on feeder speed demand to said hot damper positioning means and said cold damper positioning means to move the dampers in opposite directions on changes in feed speed demand.
References Cited (Backward Citations)
US2003985A
Cited
US2419436A
Cited
US2060375A
Cited
US2152367A
Cited
US2226923A
Cited
US2894696A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-10 | 1983-06-11 | 1983-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-10 | 1987-06-11 | 1987-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-10 | 1991-06-11 | 1991-12-11 | $7700.00 | Window Closed / Lapsed |