US4212202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distributed compensation for capacitance-type fluid measuring apparatus
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1979-08-09
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Granted: 1980-07-15
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Expires: 1999-08-09
Abstract
Abstract A capacitance-type fluid gage has the probe electrode shaped in accordance with a specified function of container volume and the relative dielectric of the fluid to be gaged.
Inventors
- 👤 Charles C. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:17
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/26; G01F23/263
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
108 words
Capacitance fluid measuring means for measuring the mass of a dielectric fluid in a container wherein the mass of fluid in the container is related to the dielectric k, of said fluid and to the level of the fluid in the container through a mathematical expression of the form of said container, f(V), and wherein ##EQU22## where a and b are constants relating to the fluid, k o is the relative nominal dielectric constant of the fluid and V is the normalized volume of fluid in the container at a given fluid level, said fluid measuring means including a capacitor probe having electrodes contoured in accordance with f(V).
Claim 2
Dependent Claim
108 words
Capacitance fluid measuring means for measuring the mass of a dielectric fluid in a container wherein the mass of fluid in the container is related to the dielectric k, of said fluid and to the level of the fluid in the container through a mathematical expression of the form of said container, f(V), and wherein ##EQU22## where a and b are constants relating to the fluid, k o is the relative nominal dielectric constant of the fluid and V is the normalized volume of fluid in the container at a given fluid level, said fluid measuring means including a capacitor probe having electrodes contoured in accordance with f(V).
Claim 3
Dependent Claim
20 words
The capacitance fluid measuring means of claim 1 with additionally a fixed capacitor, connected in series with said capacitor probe.
Claim 4
Dependent Claim
26 words
The capacitance fluid measuring means of claims 1 or 2 where a is about 0.127 and b is about 0.0368 when V is expressed in gallons.
Claim 5
Dependent Claim
28 words
The capacitance fluid measuring means of claims 1 or 2 where fluid density D is related to fluid dielectric k by an expression of the following form ##EQU23##
Claim 6
Dependent Claim
58 words
The capacitance fluid measuring means of claim 2 wherein said fixed capacitor has a capacitance of C f farads and said capacitor probe has a capacitance of C po farads when said container is empty of fluid to be measured and wherein a and b are related to C f and C po as follows: (b/a)=C.sub.po /(C.sub.f +C.sub.po).
Claim 7
Independent Claim
152 words
The method of designing a capacitance-type fluid measuring apparatus comprising a capacitor probe and having distributed compensation for use in a fluid container tank comprising: determining the quantity of fluid, V f , in the tank for a plurality of fluid levels; determining the value ##EQU24## for each V f where V=V f /V fmax V fmax =total tank capacity a and b are constants associated with the fluid to be measured, and k o =relative dielectric constant of the fluid determining the height of fluid in the tank for each value of f(V); and, determining the shape of the capacitor probe by dimensioning the probe along the height of the fluid in accordance with: ##EQU25## where C po is the capacitance of the measuring apparatus in the tank when the tank is effectively empty, h is the height of fluid in the tank and ε is the permittivity of free space.
Claim 8
Independent Claim
152 words
The method of designing a capacitance-type fluid measuring apparatus comprising a capacitor probe and having distributed compensation for use in a fluid container tank comprising: determining the quantity of fluid, V f , in the tank for a plurality of fluid levels; determining the value ##EQU24## for each V f where V=V f /V fmax V fmax =total tank capacity a and b are constants associated with the fluid to be measured, and k o =relative dielectric constant of the fluid determining the height of fluid in the tank for each value of f(V); and, determining the shape of the capacitor probe by dimensioning the probe along the height of the fluid in accordance with: ##EQU25## where C po is the capacitance of the measuring apparatus in the tank when the tank is effectively empty, h is the height of fluid in the tank and ε is the permittivity of free space.
Claim 9
Dependent Claim
64 words
The method of claim 6 with an additional step of: determining the value, C f , of a fixed capacitor to be arranged serially with the capacitor probe to maintain a linear relationship between C p and equivalent fluid level where C p is the capacitance of the measuring apparatus along the height of the fluid to be measured for each value of f(V).
Claim 10
Independent Claim
23 words
The method of claims 6 and 7 wherein a is about 0.127 and b is about 0.0368 when V is expressed in gallons.
Claim 11
Independent Claim
25 words
The method of claims 6 or 7 wherein fluid density D is related to fluid dielectric k by an expression of the following form: ##EQU26##
Claim 12
Dependent Claim
7 words
The method of claim 7 wherein: ##EQU27##
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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) | 1983-07-15 | 1984-01-14 | 1984-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-15 | 1988-01-14 | 1988-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-15 | 1992-01-14 | 1992-07-15 | $7700.00 | Window Closed / Lapsed |