US3781660A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Conductivity meter for measuring distillate hydrocarbon fuels
Assignee: Western Atlas International Inc
•
Filing: 1972-05-11
•
Granted: 1973-12-25
•
Expires: 1992-05-11
Abstract
Abstract Disclosed herein is a conductivity meter adapted for use in measuring the conductivity of distillate hydrocarbon fuels, comprising a conductivity probe, a direct current power source (e.g., nickel cadmium battery), an amplifier, and an ammeter calibrated in units of conductivity (e.g., picomhos per meter). The conductivity probe comprises two series of closely spaced plates of high surface area. The amplifier is of the high gain high input impedance (FET) operational type. The amplifier and battery are contained in a thermally insulated housing having a self-contained heating unit and heat sink.
Inventors
- 👤 W Ludt
- 👤 E Lombardi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:54
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/22; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
173 words
A conductivity meter especially adapted to measure the conductivity of distillate hydrocarbon fuels, said meter comprising A. a conductivity probe comprising two series of electrically connected conductive plates, said series of plates being positioned such that the plates of one of said series are proximate to but electrically separated from tHe plates of the other of said series of plates such that the liquid being measured fills the space between said plates and the total surface area of each of said series of plates being at least about 30 square inches; B. a direct current voltage source operatively connected to supply a voltage difference between each of said series of plates; C. a field effect transistor input operational amplifier provided with a pico-amp offset current operatively connected to amplify the signal produced when electrical current flows from one of said series of plates to the other of said series of plates; and D. an ammeter connected to the output of said amplifier and adapted to respond to the output signal of said amplifier.
Claim 2
Dependent Claim
173 words
A conductivity meter especially adapted to measure the conductivity of distillate hydrocarbon fuels, said meter comprising A. a conductivity probe comprising two series of electrically connected conductive plates, said series of plates being positioned such that the plates of one of said series are proximate to but electrically separated from tHe plates of the other of said series of plates such that the liquid being measured fills the space between said plates and the total surface area of each of said series of plates being at least about 30 square inches; B. a direct current voltage source operatively connected to supply a voltage difference between each of said series of plates; C. a field effect transistor input operational amplifier provided with a pico-amp offset current operatively connected to amplify the signal produced when electrical current flows from one of said series of plates to the other of said series of plates; and D. an ammeter connected to the output of said amplifier and adapted to respond to the output signal of said amplifier.
Claim 3
Dependent Claim
15 words
The meter of claim 1 wherein said direct current voltage source comprises a nickel-cadmium battery.
Claim 4
Dependent Claim
24 words
The meter of claim 2 further characterized by inclusion of a thermally insulated housing, said battery and said amplifier being contained within said housing.
Claim 5
Dependent Claim
59 words
The meter of claim 3 further characterized by inclusion of electrical heating means within said housing and a mass of heat sink material, said heating means being adapted to heat said heat sink material such that the temperature within said housing remains substantially stable for an extended period during use of said meter in an environment of changing temperature.
Claim 6
Dependent Claim
55 words
The meter of claim 4 further characterized by having a plurality of adjustable resistors connected in parallel in the output signal circuit from said amplifier and a range selector switch adapted to include any one at a time of said plurality of adjustable resistors in the output signal connection of said amplifier to said ammeter.
Claim 7
Dependent Claim
27 words
The meter of claim 5 further characterized by inclusion of a shunt circuit between the terminals of said ammeter and a shunt switch in said shunt circuit.
Claim 8
Dependent Claim
36 words
The meter of claim 6 further characterized by inclusion of a power switch in the connection of said direct current power source adapted to disconnect said power source when said conductivity meter is not in use.
Claim 9
Dependent Claim
31 words
The meter of claim 7 further characterized by inclusion of means for interlocking said power switch and said shunt switch such that one switch is closed when the other is open.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |