US3728897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compensated fuel gage
Assignee: CONS AIRBORNE SYSTEMS
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Filing: 1970-11-16
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Granted: 1973-04-24
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Expires: 1990-11-16
Abstract
Abstract A temperature sensing element responsive to the temperature of the fuel in a tank is connected in one part of the bridge circuit of a capacitance fuel gage. The temperature sensing element compensates for variations in the dielectric constant and density of the fuel and permits a linear readout of the mass of the fuel.
Inventors
- 👤 I Wallman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:19
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/26; G01F23/263
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
158 words
A capacitance mass fuel gage comprising a capacitance probe immersed in the fuel, the reactance of said capacitance being a function of the level of said fuel and of the dielectric constant of said fuel, said capacitor connected in a first arm of a bridge circuit, a center tapped transformer forming two further bridge arms, a fixed capacitor connected to a fourth arm of said bridge, energizing means adapted to be connected across one bridge diagonal, amplifying means adapted to be connected across the second diagonal, feedback means responsive to the output from said amplifying means and connected back to the input of said amplifying means and compensation means generating a temperature dependent signal having the relationship F (t) (K-1)/D , wherein K is the dielectric constant, D is the density and F being a predetermined function of temperature chosen to compensate for both density and dielectric constant, said compensation means being electrically connected within said bridge circuit.
Claim 2
Dependent Claim
158 words
A capacitance mass fuel gage comprising a capacitance probe immersed in the fuel, the reactance of said capacitance being a function of the level of said fuel and of the dielectric constant of said fuel, said capacitor connected in a first arm of a bridge circuit, a center tapped transformer forming two further bridge arms, a fixed capacitor connected to a fourth arm of said bridge, energizing means adapted to be connected across one bridge diagonal, amplifying means adapted to be connected across the second diagonal, feedback means responsive to the output from said amplifying means and connected back to the input of said amplifying means and compensation means generating a temperature dependent signal having the relationship F (t) (K-1)/D , wherein K is the dielectric constant, D is the density and F being a predetermined function of temperature chosen to compensate for both density and dielectric constant, said compensation means being electrically connected within said bridge circuit.
Claim 3
Dependent Claim
45 words
A fuel gage as in claim 1 wherein said compensation means comprises a temperature stable element in series with said capacitance probe, a temperature sensing element in parallel with said temperature stable element and a further temperature sensing element in parallel with said series combination.
Claim 4
Dependent Claim
28 words
A fuel gage as in claim 2 wherein said temperature sensing element and said temperature stable element are resistors and said further temperature sensing element is a capacitor.
Claim 5
Dependent Claim
44 words
A capacitance fuel gage as in claim 1 further comprising a servomotor coupled to the output of said amplifying means, potentiometer means connected across one of said further bridge arms, said servomotor adjusting said potentiometer and said feedback means connected to the potentiometer output.
Claim 6
Dependent Claim
32 words
A capacitance fuel gage as in claim 1 further comprising a potentiometer placed in parallel with one of said further bridge arms, said fixed capacitor connected to the output of said potentiometer.
Claim 7
Dependent Claim
37 words
A fuel gage as in claim 1 further comprising an indicator wherein said fuel gage requires two wires to connect to said indicator, and wherein said indicator provides a linear readout of the mass of said fuel.
Claim 8
Dependent Claim
28 words
A fuel gage as in claim 1 wherein said compensation means is contained within a housing and said housing is filled with epoxy resin encapsulating said compensation means.
Claim 9
Dependent Claim
127 words
A capacitance fuel gage comprising a capacitance probe immersed in the fuel, the reactance of said capacitance being a function of the level of said fuel and of the dielectric constant of said fuel, said capacitor connected in a first arm of a bridge circuit, a center tapped transformer forming two further bridge arms, a fixed capacitor connected to a fourth arm of said bridge, energizing means connected across one bridge diagonal, amplifying means connected across the second diagonal, feedback means responsive to the output from said amplifying means and connected back to the input of said amplifying means, and compensation means comprising a temperature sensing element responsive to the temperature of said fuel connected in said feedback means to compensate for variations in said dielectric constant.
Claim 10
Dependent Claim
127 words
A capacitance fuel gage comprising a capacitance probe immersed in the fuel, the reactance of said capacitance being a function of the level of said fuel and of the dielectric constant of said fuel, said capacitor connected in a first arm of a bridge circuit, a center tapped transformer forming two further bridge arms, a fixed capacitor connected to a fourth arm of said bridge, energizing means connected across one bridge diagonal, amplifying means connected across the second diagonal, feedback means responsive to the output from said amplifying means and connected back to the input of said amplifying means, and compensation means comprising a temperature sensing element responsive to the temperature of said fuel connected in said feedback means to compensate for variations in said dielectric constant.
Claim 11
Dependent Claim
73 words
A capacitance mass fuel gage of the bridge type having a fuel level responsive capacitance in one arm of the bridge and furTher comprising compensation means generating a temperature dependant signal having the relationship F (t) (K-1)/D , wherein K is the dielectric constant, D in the density and F being a predetermined function of temperature chosen to compensate for both density and dielectric constant, said compensation means being connected within said bridge.
Claim 12
Dependent Claim
73 words
A capacitance mass fuel gage of the bridge type having a fuel level responsive capacitance in one arm of the bridge and furTher comprising compensation means generating a temperature dependant signal having the relationship F (t) (K-1)/D , wherein K is the dielectric constant, D in the density and F being a predetermined function of temperature chosen to compensate for both density and dielectric constant, said compensation means being connected within said bridge.
Claim 13
Dependent Claim
50 words
A fuel gage as in claim 9 wherein said compensation means comprises a first temperature sensing element serially connected in one arm of said bridge, a temperature stable element in parallel with said first temperature sensing element and a second temperature sensing element in parallel with said one bridge arm.
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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) | 1976-04-23 | 1976-10-23 | 1977-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-23 | 1980-10-23 | 1981-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-23 | 1984-10-23 | 1985-04-24 | $7700.00 | Window Closed / Lapsed |