US4298943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heating system
Assignee: Individual
•
Filing: 1979-06-07
•
Granted: 1981-11-03
•
Expires: 1999-06-07
Abstract
Abstract A method and system for modifying a conventional furnace are disclosed whereby greatly improved furnace operating efficiency is obtained. The temperature of the structure, the outside temperature, and the temperature of the heat exchange fluid are measured. The rate of flow of fuel to the furnace is adjusted as a function of the difference between the outside temperature and the desired temperature of the structure. The fuel rate flow is further adjusted as a function of the difference between the furnace's heat exchange fluid temperature and the actual interior temperature of the structure. A further adjustment to fuel rate flow is effected as a function of the difference between the temperature of the interior of the structure and the desired structure temperature. A novel gas pressure valve is also disclosed for altering the rate of gas flow to the furnace.
Inventors
- 👤 Clement R. Tompson
- 👤 Garrett Gruner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:03
CPC Classifications
F; F23; F23N; F23N1/00; F23N1/002; G; G05; G05D; G05D16/00; G05D16/20; G05D16/2086; G05D23/00; G05D23/19; G05D23/20; G05D23/22; F23N2223/00; F23N2223/08; F23N2225/00; F23N2225/08; F23N2225/12; F23N2225/14; F23N2225/16
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
118 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature comprising: measuring a temperature outside the structure; delaying the measured outside temperature for a predetermined interval; and automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the delayed, previously measured value of the outside temperature; whereby the structure temperature achieved is substantially equal to the desired structure temperature, the furnace operates substantially continuously at a reduced energy input, and the energy input to the furnace and the energy output from the furnace vary in response to changes in the outside temperature.
Claim 2
Independent Claim
118 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature comprising: measuring a temperature outside the structure; delaying the measured outside temperature for a predetermined interval; and automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the delayed, previously measured value of the outside temperature; whereby the structure temperature achieved is substantially equal to the desired structure temperature, the furnace operates substantially continuously at a reduced energy input, and the energy input to the furnace and the energy output from the furnace vary in response to changes in the outside temperature.
Claim 3
Dependent Claim
25 words
A method as set forth in claim 1 wherein said delay interval is selected to be in the range from about one to four hours.
Claim 4
Independent Claim
111 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature comprising: measuring a temperature outside the structure; and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature, said fuel input rate being adjusted in proportion to the product of a selected outside fire ratio (OFR) factor and the difference between the desired room temperature and said outside temperature, the OFR factor being selected to effect maximum fire size when the outside temperature is at the lowest value which the furnace is designed to accommodate.
Claim 5
Independent Claim
111 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature comprising: measuring a temperature outside the structure; and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature, said fuel input rate being adjusted in proportion to the product of a selected outside fire ratio (OFR) factor and the difference between the desired room temperature and said outside temperature, the OFR factor being selected to effect maximum fire size when the outside temperature is at the lowest value which the furnace is designed to accommodate.
Claim 6
Dependent Claim
138 words
For use with a heating system which includes a furnace for heating a structure by means of a heat exchange fluid, a method of controlling the energy released by the furnace for efficiently heating the structure to a desired temperature comprising: measuring a temperature outside the structure; automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; readjusting the fuel input rate to the furnace by: measuring the temperature of the heat exchange fluid; measuring the actual temperature of the interior of the structure; and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure.
Claim 7
Dependent Claim
138 words
For use with a heating system which includes a furnace for heating a structure by means of a heat exchange fluid, a method of controlling the energy released by the furnace for efficiently heating the structure to a desired temperature comprising: measuring a temperature outside the structure; automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; readjusting the fuel input rate to the furnace by: measuring the temperature of the heat exchange fluid; measuring the actual temperature of the interior of the structure; and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure.
Claim 8
Independent Claim
178 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by means of a heat exchange fluid, comprising: measuring a temperature outside the structure; measuring the temperature of the heat exchange fluid; measuring the actual temperature of the interior of the structure; automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, said alteration being effected as a function of the product of a selected plenum fire ratio (PFR) factor and the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, where the PFR factor is a measure of the percent change in furnace fire size required to change the temperature of the heat exchange fluid by one degree.
Claim 9
Independent Claim
178 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by means of a heat exchange fluid, comprising: measuring a temperature outside the structure; measuring the temperature of the heat exchange fluid; measuring the actual temperature of the interior of the structure; automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, said alteration being effected as a function of the product of a selected plenum fire ratio (PFR) factor and the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, where the PFR factor is a measure of the percent change in furnace fire size required to change the temperature of the heat exchange fluid by one degree.
Claim 10
Independent Claim
177 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by means of a heat exchange fluid, comprising: measuring a temperature outside the structure; measuring the temperature of the heat exchange fluid; measuring the actual temperature of the interior of the structure; automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, said alteration including: computing a factor A corresponding to the difference between desired structure temperature and the outside temperature minus the actual structure temperature; subtracting from the factor A a factor B corresponding to the difference between the temperature of the heat exchange fluid and the actual structure temperature; and altering the fuel input rate as a function of the difference between the factors A and B.
Claim 11
Independent Claim
177 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by means of a heat exchange fluid, comprising: measuring a temperature outside the structure; measuring the temperature of the heat exchange fluid; measuring the actual temperature of the interior of the structure; automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, said alteration including: computing a factor A corresponding to the difference between desired structure temperature and the outside temperature minus the actual structure temperature; subtracting from the factor A a factor B corresponding to the difference between the temperature of the heat exchange fluid and the actual structure temperature; and altering the fuel input rate as a function of the difference between the factors A and B.
Claim 12
Dependent Claim
80 words
A method as set forth in claim 6 wherein said outside temperature is an outside temperature delayed by a predetermined interval, and wherein the factor A is multiplied by a selected KST factor prior to subtracting the factor B therefrom, where the KST factor is indicative of the number of degrees the heat exchange temperature must increase for each degree increase in the difference between the outside temperature and the structure temperature to hold the structure at a constant temperature.
Claim 13
Dependent Claim
83 words
A method as set forth in claim 7 further including multiplying the difference between factors A and B by a selected plenum fire ratio (PFR) factor where the PFR factor is a measure of the percent change in furnace fire size required to change the temperature of the heat exchange fluid by one degree, and wherein the altering of the fuel input rate is effected in proportion to the product of the PFR factor and the difference between the factors A and B.
Claim 14
Independent Claim
98 words
A method of controlling the energy released by a furnace for efficiently heating s structure to a desired temperature comprising: measuring a temperature outside the structure; automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; measuring the actual temperature of the interior of the structure; and further adjusting the fuel input rate to the furnace as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 15
Independent Claim
98 words
A method of controlling the energy released by a furnace for efficiently heating s structure to a desired temperature comprising: measuring a temperature outside the structure; automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; measuring the actual temperature of the interior of the structure; and further adjusting the fuel input rate to the furnace as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 16
Independent Claim
161 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature comprising: measuring a temperature outside the structure; measuring the actual temperature of the interior of the structure; automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; and further adjusting the fuel input rate to the furnace as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature, said further adjusting including adjusting the fuel input rate to the furnace in proportion to the product of a selected structure fire ratio (SFR) factor and the difference between the structure's actual temperature and the desired structure temperature, where the SFR factor is indicative of the percent change in the furnace's full fire size desired for a change in the temperature of the structure of one degree.
Claim 17
Independent Claim
161 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired temperature comprising: measuring a temperature outside the structure; measuring the actual temperature of the interior of the structure; automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the measured outside temperature; and further adjusting the fuel input rate to the furnace as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature, said further adjusting including adjusting the fuel input rate to the furnace in proportion to the product of a selected structure fire ratio (SFR) factor and the difference between the structure's actual temperature and the desired structure temperature, where the SFR factor is indicative of the percent change in the furnace's full fire size desired for a change in the temperature of the structure of one degree.
Claim 18
Independent Claim
168 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchange fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, sensing the desired room temperature, and automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the measured external temperature; further adjusting the fuel input rate by measuring the temperature of the heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 19
Independent Claim
168 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchange fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, sensing the desired room temperature, and automatically adjusting the rate of a continuous flow of fuel to the furnace as a function of the difference between the desired temperature of the structure and the measured external temperature; further adjusting the fuel input rate by measuring the temperature of the heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 20
Dependent Claim
56 words
A method as set forth in claim 11 wherein said step of roughly adjusting the fuel input rate includes delaying the measured external temperature for a predetermined interval and automatically adjusting the fuel input rate as a function of the difference between the desired structure temperature and the delayed, previously measured value of the external temperature.
Claim 21
Independent Claim
220 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchange fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, delaying the measured external temperature for a predetermined interval, sensing the desired room temperature, and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the delayed external temperature, said function of the difference between the desired structure temperature and the delayed external temperature being proportional to an outside fire ratio (OFR) factor selected to effect maximum furnace fire size when the outside temperature is at the lowest value which the furnace is designed to accommodate; further adjusting the fuel input rate by measuring the temperature of the heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 22
Independent Claim
220 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchange fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, delaying the measured external temperature for a predetermined interval, sensing the desired room temperature, and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the delayed external temperature, said function of the difference between the desired structure temperature and the delayed external temperature being proportional to an outside fire ratio (OFR) factor selected to effect maximum furnace fire size when the outside temperature is at the lowest value which the furnace is designed to accommodate; further adjusting the fuel input rate by measuring the temperature of the heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 23
Independent Claim
234 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchange fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, delaying the measured external temperature for a predetermined interval, sensing the desired room temperature, and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the delayed external temperature; further adjusting the fuel input rate by measuring the temperature of the heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, said function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure is proportional to a selected plenum fire ratio (PFR) factor, where the PFR factor is a measure of the percent change in furnace fire size required to change the temperature of the heat exchange fluid by one degree; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 24
Independent Claim
234 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchange fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, delaying the measured external temperature for a predetermined interval, sensing the desired room temperature, and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the delayed external temperature; further adjusting the fuel input rate by measuring the temperature of the heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure, said function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure is proportional to a selected plenum fire ratio (PFR) factor, where the PFR factor is a measure of the percent change in furnace fire size required to change the temperature of the heat exchange fluid by one degree; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature.
Claim 25
Independent Claim
208 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchanger fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, delaying the measured external temperature for a predetermined interval, sensing the desired room temperature, and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the delayed external temperature; further adjusting the fuel input rate by measuring the temperature of heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature, said latter function being proportional to a selected structure fire ratio factor indicative of the percent change in the furnace's full fire size desired for a change in the temperature of the structure of one degree.
Claim 26
Independent Claim
208 words
A method of controlling the energy released by a furnace for efficiently heating a structure to a desired room temperature by means of a heat exchanger fluid, comprising: roughly adjusting the fuel input rate to the furnace by measuring a temperature external to the structure, delaying the measured external temperature for a predetermined interval, sensing the desired room temperature, and automatically adjusting the fuel input rate to the furnace as a function of the difference between the desired temperature of the structure and the delayed external temperature; further adjusting the fuel input rate by measuring the temperature of heat exchange fluid, measuring the actual temperature of the interior of the structure, and altering the fuel input rate to the furnace as a function of the difference between the temperature of the heat exchange fluid and the actual temperature of the interior of the structure; and further adjusting the fuel input rate as a function of the difference between the actual temperature of the interior of the structure and the desired structure temperature, said latter function being proportional to a selected structure fire ratio factor indicative of the percent change in the furnace's full fire size desired for a change in the temperature of the structure of one degree.
Claim 27
Independent Claim
143 words
A system for efficiently heating a structure to a desired temperature with a heat exchange fluid by controlling the energy released by a furnace which has a main gas valve and which is adapted to operate at no less than a minimum fire size, said system comprising: means for generating a first signal representative of outside temperature; means for generating a second signal representative of desired room temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals; valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace; and means responsive to the fire size signal being of a value which is too small to effect a minimum fire size for intermittently opening and closing the main gas valve.
Claim 28
Independent Claim
143 words
A system for efficiently heating a structure to a desired temperature with a heat exchange fluid by controlling the energy released by a furnace which has a main gas valve and which is adapted to operate at no less than a minimum fire size, said system comprising: means for generating a first signal representative of outside temperature; means for generating a second signal representative of desired room temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals; valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace; and means responsive to the fire size signal being of a value which is too small to effect a minimum fire size for intermittently opening and closing the main gas valve.
Claim 29
Independent Claim
130 words
A system for efficiently heating a structure to a desired temperature with a heat exchange fluid by controlling the energy released by a furnace which has a main gas valve and a thermostat for conventionally controlling actuation of the main gas valve, said system comprising: means for generating a first signal representative of outside temperature; means for generating a second signal representative of desired room temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals; valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace; and means for energizing said control means for overriding the thermostat, and for reverting to thermostat control of the furnace.
Claim 30
Independent Claim
130 words
A system for efficiently heating a structure to a desired temperature with a heat exchange fluid by controlling the energy released by a furnace which has a main gas valve and a thermostat for conventionally controlling actuation of the main gas valve, said system comprising: means for generating a first signal representative of outside temperature; means for generating a second signal representative of desired room temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals; valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace; and means for energizing said control means for overriding the thermostat, and for reverting to thermostat control of the furnace.
Claim 31
Independent Claim
116 words
A system for controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by a heat exchange fluid comprising: means for generating a first signal representative of outside temperature, including a wind chill sensor located externally of the structure and means for heating said sensor as a function of heat loss from the structure; means for generating a second signal representative of desired room temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals; and valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace.
Claim 32
Independent Claim
116 words
A system for controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by a heat exchange fluid comprising: means for generating a first signal representative of outside temperature, including a wind chill sensor located externally of the structure and means for heating said sensor as a function of heat loss from the structure; means for generating a second signal representative of desired room temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals; and valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace.
Claim 33
Dependent Claim
49 words
A system as set forth in claim 18 wherein said sensor includes a thermocouple junction, and said heating means includes a heat conductive tube extending from inside the structure to outside the structure for housing said thermocouple junction, and for conducting heat to said junction for raising its temperature.
Claim 34
Dependent Claim
29 words
A system as set forth in claim 19 wherein said tube is movable to alter the ratio of its externally exposed surface area to its internally exposed surface area.
Claim 35
Independent Claim
135 words
A system for controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by a heat exchange fluid comprising: means for generating a first signal representative of outside temperature; means for generating a second signal representative of desired room temperature; means for generating a third signal representative of actual structure temperature; means for generating a fourth signal representative of plenum temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals and receiving said third and fourth signals for altering the fire size signal responsive to the difference between said third and fourth signals; and valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace.
Claim 36
Independent Claim
135 words
A system for controlling the energy released by a furnace for efficiently heating a structure to a desired temperature by a heat exchange fluid comprising: means for generating a first signal representative of outside temperature; means for generating a second signal representative of desired room temperature; means for generating a third signal representative of actual structure temperature; means for generating a fourth signal representative of plenum temperature; control means receiving said first and second signals for developing a fire size signal as a function of the difference between said first and second signals and receiving said third and fourth signals for altering the fire size signal responsive to the difference between said third and fourth signals; and valve means responsive to said fire size signal for varying the rate of fuel flow to the furnace.
Claim 37
Dependent Claim
48 words
A system as set forth in claim 21 further including means for generating predetermined setback signals indicative of the amount and time duration by which structure temperature is to be reduced, and wherein said control means is responsive to said setback signals for reducing the fire size signal.
Claim 38
Dependent Claim
47 words
A system as set forth in claim 21 further including means for generating a heat blast signal indicative of a desired increase in structure temperature, and wherein said control means is responsive to the heat blast signal for increasing the fire size signal for a predetermined interval.
Claim 39
Dependent Claim
31 words
A system as set forth in claim 21 wherein said control means is adapted to further alter the fire size signal responsive to the difference between said second and third signals.
Claim 40
Dependent Claim
46 words
A system as set forth in claim 22 wherein the difference between second and third signals is proportioned by a selected structure fire ratio factor indicative of the percent change in the furnace's full fire size required to change the temperature of the structure one degree.
Claim 41
Dependent Claim
31 words
A system as set forth in claim 21 wherein said first signal is representative of a selected past outside temperature and said third signal is representative of present actual structure temperature.
Claim 42
Dependent Claim
48 words
A system as set forth in claim 26 wherein the difference between said first and second signals is proportioned to an outside fire ratio factor selected to effect maximum furnace fire size when the outside temperature is at the lowest value which the furnace is designed to accomodate.
Claim 43
Dependent Claim
46 words
A system as set forth in claim 26 wherein the difference between said third and fourth signals is proportioned by a PFR factor, where PRF is a measure of the percent change in furnace fire size required to change the temperature of the plenum one degree.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-02 | 1985-05-04 | 1985-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-02 | 1989-05-04 | 1989-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-02 | 1993-05-04 | 1993-11-03 | $7700.00 | Window Closed / Lapsed |