US4232300A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Level measuring system using admittance sensing
Assignee: Drexelbrook Controls Inc
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Filing: 1978-11-24
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Granted: 1980-11-04
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Expires: 1998-11-24
Abstract
Abstract A transmitting system including an admittance sensing probe having sensing elements adapted to sense both the composition and the level of materials. The probe is coupled to admittance responsive networks forming part of a common oscillator which generate admittance signals representing the level and composition of the material. A remotely located power supply provides current to the transmitters through two pairs of lines, and the output currents of the transmitters represent the level and composition of the materials.
Inventors
- 👤 William S. Wright
- 👤 Kenneth M. Loewenstern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:22
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/02; G01; G01F; G01F23/00; G01F23/22; G01F23/24; G01F23/241; G01F23/26; G01F23/263
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
147 words
In a transmitter system comprising a power supply and a load at one location and two-wire transmitter means at another location interconnected by two pairs of transmission lines carrying a variable signaling current; said transmitter means comprising: an admittance sensing means including a first condition sensing element for sensing an admittance characteristic of material corresponding to the level or condition thereof and a second compensating sensing element for sensing an admittance characteristic of the composition of said material; p1 a single oscillator; a first admittance sensing network coupled to said first sensing element and said oscillator; a second admittance sensing network coupled to said second sensing element and said oscillator; and output means coupled to said first and said second admittance sensing networks for varying the signaling current in each of said pairs of transmission lines in response to the condition and composition of said material respectively.
Claim 2
Dependent Claim
147 words
In a transmitter system comprising a power supply and a load at one location and two-wire transmitter means at another location interconnected by two pairs of transmission lines carrying a variable signaling current; said transmitter means comprising: an admittance sensing means including a first condition sensing element for sensing an admittance characteristic of material corresponding to the level or condition thereof and a second compensating sensing element for sensing an admittance characteristic of the composition of said material; p1 a single oscillator; a first admittance sensing network coupled to said first sensing element and said oscillator; a second admittance sensing network coupled to said second sensing element and said oscillator; and output means coupled to said first and said second admittance sensing networks for varying the signaling current in each of said pairs of transmission lines in response to the condition and composition of said material respectively.
Claim 3
Dependent Claim
41 words
A transmitter according to claim 1 wherein said first sensing network includes a first admittance measured between said first sensing element and ground and said second admittance sensing network includes a second admittance measured between said second sensing element and ground.
Claim 4
Dependent Claim
41 words
A transmitter system according to claim 2 wherein said first admittance sensing network and said second admittance sensing network include a guard element disposed between said first sensing element and said second sensing element and driven at substantially the same potential.
Claim 5
Dependent Claim
52 words
A transmitter system according to claim 1 wherein said first admittance sensing network includes insulation separating said first sensing element from said material and said second sensing element from said material, the thickness and dielectric constant of said insulation at said first sensing element and said second sensing element being substantially equal.
Claim 6
Dependent Claim
39 words
A transmitter system according to claim 4 wherein said first admittance sensing network includes a first bridge and said second admittance sensing network includes a second bridge, said first bridge and said second bridge forming part of said oscillator.
Claim 7
Dependent Claim
18 words
A transmitter system according to claim 1 further including first and second power supplies coupled to said oscillator.
Claim 8
Dependent Claim
14 words
A transmitter system according to claim 6 wherein said power supplies are individually adjustable.
Claim 9
Dependent Claim
39 words
A transmitter system according to claim 1 further including means at said one location for combining said signaling current from said pairs of transmission lines so as to generate a signal reflecting the condition corrected for changes in composition.
Claim 10
Dependent Claim
34 words
A transmitter system according to claim 8 wherein said means at said one location comprises means for dividing signaling current from one of said pairs by signaling current from the other of said pairs.
Claim 11
Dependent Claim
124 words
A transmitter system comprising a power supply and a load at one location and two-wire transmitter means at another location interconnected by two pairs of transmission lines carrying a variable signaling current, said transmitter means comprising: an admittance sensing means including a first admittance sensing element and a second admittance sensing element; a single oscillator including, a first admittance sensing network including admittance associated with said first sensing element; a second admittance sensing network including admittance associated with said second sensing element; and output means coupled to said first and said second admittance sensing networks for varying the signaling current in each of said pairs of transmission lines in response to the admittance sensed by said first sensing element and said second sensing element.
Claim 12
Dependent Claim
124 words
A transmitter system comprising a power supply and a load at one location and two-wire transmitter means at another location interconnected by two pairs of transmission lines carrying a variable signaling current, said transmitter means comprising: an admittance sensing means including a first admittance sensing element and a second admittance sensing element; a single oscillator including, a first admittance sensing network including admittance associated with said first sensing element; a second admittance sensing network including admittance associated with said second sensing element; and output means coupled to said first and said second admittance sensing networks for varying the signaling current in each of said pairs of transmission lines in response to the admittance sensed by said first sensing element and said second sensing element.
Claim 13
Dependent Claim
139 words
In a transmitter system comprising a power supply and a load at one location and transmitter means at another location interconnected by a plurality of transmission lines carrying signals; said transmitter means comprising: an admittance sensing means including a first condition sensing element for sensing an admittance characteristic of material corresponding to the level or condition thereof and a second compensating sensing element for sensing an admittance characteristic of the composition of said material; a single oscillator; a first admittance sensing network coupled to said first sensing element and said oscillator; a second admittance sensing network coupled to said second sensing element and said oscillator; and output means coupled to said first and said second admittance sensing networks for varying the signals in said plurality of transmission lines in response to the condition and composition of said material respectively.
Claim 14
Dependent Claim
139 words
In a transmitter system comprising a power supply and a load at one location and transmitter means at another location interconnected by a plurality of transmission lines carrying signals; said transmitter means comprising: an admittance sensing means including a first condition sensing element for sensing an admittance characteristic of material corresponding to the level or condition thereof and a second compensating sensing element for sensing an admittance characteristic of the composition of said material; a single oscillator; a first admittance sensing network coupled to said first sensing element and said oscillator; a second admittance sensing network coupled to said second sensing element and said oscillator; and output means coupled to said first and said second admittance sensing networks for varying the signals in said plurality of transmission lines in response to the condition and composition of said material respectively.
Claim 15
Dependent Claim
42 words
A transmitter system according to claim 11 further including means at said one location for combining said signals from said plurality of transmission lines so as to generate a signal reflecting the condition corrected for changes in dielectric constant of the composition.
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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) | 1983-11-04 | 1984-05-05 | 1984-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-04 | 1988-05-05 | 1988-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-04 | 1992-05-05 | 1992-11-04 | $7700.00 | Window Closed / Lapsed |