US6705533B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital modulation for a gas-fired heater
Assignee: Arthur D Little Inc
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Filing: 2001-04-20
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Granted: 2004-03-16
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Expires: 2021-04-20
Abstract
Abstract A method is disclosed for operating a gas-fired heater to maintain temperature within a zone. The gas-fired heater is modulated between a higher firing rate and a lower firing rate within a pseudo steady-state mode until a current firing rate exceeds a predetermined maximum time period t trans . The gas-fired heater is then modulated between an updated higher firing rate and an updated lower firing rate within a transient mode until an updated current firing rate exceeds a predetermined maximum time period t diag . Finally, the higher firing rate and the lower firing rate are redefined in a diagnostic mode until the gas-fired heater returns to the pseudo steady-state mode.
Inventors
- 👤 Steven Casey
- 👤 John Bowman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:14
CPC Classifications
F; F23; F23N; F23N1/00; F23N1/002; F23N5/00; F23N5/02; F23N5/022; F23N2223/00; F23N2223/08; F23N2223/22; F23N2225/00; F23N2225/08; F23N2225/12; F23N2227/00; F23N2227/10; F23N2237/00; F23N2237/02; F23N2241/00; F23N2241/02; F23N5/24
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
109 words
A method of operating a gas-fired heater to maintain temperature within a zone, the method comprising: modulating the gas-fired heater between a higher firing rate and a lower firing rate within a pseudo steady-state mode until a current firing rate exceeds a predetermined maximum time period t trans ; modulating the gas-fired heater between an updated higher firing rate and an updated lower firing rate within a transient mode until an updated current firing rate exceeds a predetermined maximum time period t diag ; and redefining the higher firing rate and the lower firing rate in a diagnostic mode until the gas-fired heater returns to the pseudo steady-state mode.
Claim 2
Independent Claim
109 words
A method of operating a gas-fired heater to maintain temperature within a zone, the method comprising: modulating the gas-fired heater between a higher firing rate and a lower firing rate within a pseudo steady-state mode until a current firing rate exceeds a predetermined maximum time period t trans ; modulating the gas-fired heater between an updated higher firing rate and an updated lower firing rate within a transient mode until an updated current firing rate exceeds a predetermined maximum time period t diag ; and redefining the higher firing rate and the lower firing rate in a diagnostic mode until the gas-fired heater returns to the pseudo steady-state mode.
Claim 3
Dependent Claim
66 words
The method of claim 1 wherein the step of modulating the gas-fired heater within the pseudo steady-state mode further comprises: determining whether a thermostat is satisfied or unsatisfied; stepping burners to the higher firing rate for an unsatisfied thermostat and the lower firing rate for a satisfied thermostat; and initiating one of a warming timer and a cooling timer to determine whether t trans is obtained.
Claim 4
Dependent Claim
67 words
The method of claim 1 wherein the step of modulating the gas-fired heater within the transient mode further comprises: determining whether a thermostat is satisfied or unsatisfied; stepping burners to the updated higher firing rate for an unsatisfied thermostat and the updated lower firing rate for a satisfied thermostat; and initiating one of a warming timer and a cooling timer to determine whether t diag is obtained.
Claim 5
Dependent Claim
122 words
The method of claim 1 wherein the step of modulating the gas-fired heater within the diagnostic mode further comprises: determining a second time whether the thermostat is satisfied or unsatisfied; stepping burners to a full firing rate for an unsatisfied thermostat; stepping burners to full off for a satisfied thermostat; monitoring the thermostat for a change to either satisfied or unsatisfied; stepping burners to the updated higher firing rate when the thermostat becomes satisfied; stepping burners to the updated lower firing rate when the thermostat becomes unsatisfied; monitoring the thermostat for another change to either unsatisfied or satisfied; stepping the burners to the fall firing rate when the thermostat becomes unsatisfied; and stepping burners to full off when the thermostat becomes satisfied.
Claim 6
Dependent Claim
124 words
The method of claim 4 wherein the step of redefining the higher firing rate and the lower firing rate in the diagnostic mode further comprises: calculating a weighted average overall firing rate over a last thermostat cycle, either from unsatisfied to satisfied or from satisfied to unsatisfied; for the thermostat cycle going from satisfied to unsatisfied, redefining the higher firing rate based upon the weighted average overall firing rate and redefining the lower firing rate based upon the redefined higher firing rate; for the thermostat cycle going from unsatisfied to satisfied, redefining the lower firing rate based upon the weighted average overall firing rate and redefining the higher firing rate based upon the redefined lower firing rate; and returning to a pseudo steady-state mode.
Claim 7
Dependent Claim
64 words
The method of claim 1 wherein the step of redefining the higher firing rate and the lower firing rate in the diagnostic mode further comprises: calculating a number of steps to different firing rates required in the diagnostic mode before return to pseudo steady-state mode; and calculating a redefined higher firing rate and a redefined lower firing rate based upon the number of steps.
Claim 8
Dependent Claim
24 words
The method of claim 1 further comprising: entering an ignition detection mode prior to adjusting a higher firing rate or a lower firing rate.
Claim 9
Independent Claim
106 words
A method of operating a gas-fired heater with a modulator to maintain temperature within a zone, the method comprising: operating the modulator at a higher firing rate when the zone is not sufficiently heated; operating the modulator at a lower firing rate when the zone is sufficiently heated; toggling between the higher firing rate and the lower firing rate in a pseudo steady-state mode; sensing an updated heat requirement from a thermostat; adjusting the higher firing rate and the lower firing rate based upon the updated heat requirement in a transient mode; and toggling between an adjusted higher firing rate and an adjusted lower firing rate.
Claim 10
Independent Claim
106 words
A method of operating a gas-fired heater with a modulator to maintain temperature within a zone, the method comprising: operating the modulator at a higher firing rate when the zone is not sufficiently heated; operating the modulator at a lower firing rate when the zone is sufficiently heated; toggling between the higher firing rate and the lower firing rate in a pseudo steady-state mode; sensing an updated heat requirement from a thermostat; adjusting the higher firing rate and the lower firing rate based upon the updated heat requirement in a transient mode; and toggling between an adjusted higher firing rate and an adjusted lower firing rate.
Claim 11
Dependent Claim
34 words
The method of claim 8 further comprising: entering a diagnostic mode when one of the adjusted higher firing rate and the adjusted lower firing rate exceeds a predetermined maximum time period t diag .
Claim 12
Dependent Claim
21 words
The method of claim 9 further comprising: redefining the higher firing rate and the lower firing rate within the diagnostic mode.
Claim 13
Dependent Claim
31 words
The method of claim 10 further comprising: calculating a redefined higher firing rate and a redefined lower firing rate based upon a weighted average of overall firing rates within a cycle.
Claim 14
Dependent Claim
24 words
The method of claim 11 further comprising: entering the pseudo steady-state mode using the redefined higher firing rate and the redefined lower firing rate.
Claim 15
Independent Claim
136 words
A method of operation of a gas-fired heater comprising: operating the gas-fired heater within a load zone between a high firing rate and low firing rate in a pseudo steady-state mode of operation; sensing a change in a demand signal within a prescribed time period t trans ; entering a transient mode if no change is sensed within t tran s; sensing a change in a demand signal within a second prescribed time period, t diag ; entering a diagnostic mode if no change is sensed within t diag ; driving a firing rate of the gas-fired heater over a plurality of increments to determine a new load zone; estimating a new high firing rate and a new low firing rate based upon the new load zone; and returning to the pseudo steady-state mode of operation.
Claim 16
Independent Claim
136 words
A method of operation of a gas-fired heater comprising: operating the gas-fired heater within a load zone between a high firing rate and low firing rate in a pseudo steady-state mode of operation; sensing a change in a demand signal within a prescribed time period t trans ; entering a transient mode if no change is sensed within t tran s; sensing a change in a demand signal within a second prescribed time period, t diag ; entering a diagnostic mode if no change is sensed within t diag ; driving a firing rate of the gas-fired heater over a plurality of increments to determine a new load zone; estimating a new high firing rate and a new low firing rate based upon the new load zone; and returning to the pseudo steady-state mode of operation.
References Cited (Backward Citations)
US3419775A
Cited
US3308869A
Cited
US3797988A
Cited
US4257318A
Cited
US4252300A
Cited
US4443157A
Cited
US4431131A
Cited
US4476850A
Cited
US4614491A
Cited
US4887958A
Cited
US4874311A
Cited
US5295820A
Cited
US5749718A
Cited
US5513979A
Cited
US5470018A
Cited
US5660542A
Cited
US5549469A
Cited
US5813320A
Cited
US5934431A
Cited
US5931652A
Cited
US5961317A
Cited
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