US3786345A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Measuring equipment, especially for measuring the ph-value of a liquid
Assignee: Radiometer AS
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Filing: 1971-06-18
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Granted: 1974-01-15
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Expires: 1991-06-18
Abstract
Abstract A measuring equipment is disclosed, in which a physical quantity to be measured is transformed into an electrical magnitude, such as a voltage or a current, and as such amplified in an amplifier and transferred via a two-wire cable to a device for indicating, recording or in other ways utilizing the result of the measurement, wherein the transfer cable simultaneously is used to supply the power to the amplifier in that the information concerning the measurement is converted into a current forming part of the supply current to the amplifier. Further disclosed in such equipment, is a galvanic separation which is provided in the two-wire cable for supplying power to the amplifier and for transferring the information to the utilizing device.
Inventors
- 👤 S Mikkelsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:00
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/02; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/4166; G01N27/4167
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
142 words
A measuring equipment, especially for measuring the pH-value of a liquid, comprising transducer means for converting the quantity to be measured into an electric magnitude, amplifier means adapted for converting its input signal into a corresponding variation in its supply current, first electric conductor means connecting the transducer means to the amplifier means for conducting the electric magnitude as an input signal to the amplifier means, a measured value utilizing device having means for producing the supply current for the amplifier means and means for deriving a measurement result from the value of the supply current, second electric two-wire conductor means connecting the amplifier means to the utilizing device for conducting supply current from the latter to the former, and separator means forming part of the second conductor means for providing a galvanic separation of the amplifier means from the utilizing device.
Claim 2
Dependent Claim
142 words
A measuring equipment, especially for measuring the pH-value of a liquid, comprising transducer means for converting the quantity to be measured into an electric magnitude, amplifier means adapted for converting its input signal into a corresponding variation in its supply current, first electric conductor means connecting the transducer means to the amplifier means for conducting the electric magnitude as an input signal to the amplifier means, a measured value utilizing device having means for producing the supply current for the amplifier means and means for deriving a measurement result from the value of the supply current, second electric two-wire conductor means connecting the amplifier means to the utilizing device for conducting supply current from the latter to the former, and separator means forming part of the second conductor means for providing a galvanic separation of the amplifier means from the utilizing device.
Claim 3
Dependent Claim
59 words
A measuring equipment as claimed in claim 1, wherein the means for producing the supply current in the utilizing device is in the form of a direct current power supply, and wherein the separator means comprises a dc-ac-converter supplied from the direct current power supply generator, a transformer supplied from the dc-ac-converter, and an ac-dc-converter supplied from the transformer.
Claim 4
Dependent Claim
48 words
A measuring equipment as claimed in claim 2, wherein the dc-ac-converter comprises a self-running multivibrator, switching means inserted in the current path from the direct current power supply to the transformer, and means for controlling the switching of the switching means by the output voltage of the multivibrator.
Claim 5
Dependent Claim
59 words
A measuring equipment as claimed in claim 1, wherein the transducer means comprises a glass electrode and a reference electrode being arranged in a liquid the pH-value of which is being measured, and wherein the amplifier means comprises a feed-back loop for negative voltage feed-back, a temperature-dependent resistor being arranged in the liquid, included in the feed back loop.
Claim 6
Dependent Claim
161 words
A measuring equipment, especially for measuring the pH-value of a liquid, comprising transducer means for converting the quantity to be measured into an electric magnitude, an amplifier having a plurality of stages and having input terminals and supply terminals, means in the final stage of the amplifier, included in a circuit between the supply terminals of the amplifier and adapted for varying its internal resistEnce in dependence on the input signal applied to the input terminals of the amplifier, first electric conductor means connecting the transducer means to the input terminals of the amplifier, a measured value utilizing device having means for producing the supply current for the amplifier and means for deriving a measurement result from the value of the supply current, second electric two-wire conductor means connecting the supply terminals of the amplifier to the utilizing device, and separator means forming part of the second conductor means for providing a galvanic separation of the amplifier from the utilizing device.
Claim 7
Dependent Claim
161 words
A measuring equipment, especially for measuring the pH-value of a liquid, comprising transducer means for converting the quantity to be measured into an electric magnitude, an amplifier having a plurality of stages and having input terminals and supply terminals, means in the final stage of the amplifier, included in a circuit between the supply terminals of the amplifier and adapted for varying its internal resistEnce in dependence on the input signal applied to the input terminals of the amplifier, first electric conductor means connecting the transducer means to the input terminals of the amplifier, a measured value utilizing device having means for producing the supply current for the amplifier and means for deriving a measurement result from the value of the supply current, second electric two-wire conductor means connecting the supply terminals of the amplifier to the utilizing device, and separator means forming part of the second conductor means for providing a galvanic separation of the amplifier from the utilizing device.
Claim 8
Dependent Claim
38 words
A measuring equipment as claimed in claim 5, further comprising a number of constant current source circuits included in the amplifier and adapted to transfer constant supply current to the stages of the amplifier preceding the final stage.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |