US3887335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical measuring and monitoring apparatus utilising a remote detector
Assignee: Charbonnages de France CDF
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Filing: 1973-11-27
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Granted: 1975-06-03
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Expires: 1993-11-27
Abstract
Abstract An apparatus for measuring and monitoring the combustible gas content of a gaseous mixture, for example in a mine, comprises a detector for location remote from a measuring and monitoring unit. A control circuit in the measuring unit maintains a constant voltage at sensing elements of the detector regardless of the length of cable connecting the detector to the measuring unit.
Inventors
- 👤 Maurice Boutonnat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:16
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/14; G01N27/16; G08; G08C; G08C19/00; G08C19/02
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
174 words
AN ELECTRICAL APPARATUS FOR MEASURING AND MONITORING A PARAMETER, COMPRISING MEASURING AND MONITORING MEANS FOR GENERATING A MEASUREMENT SIGNAL, DETECTOR MEANS ADAPTED FOR CONNECTION TO SAID MEASURING AND MONITORING MEANS AND ADAPTED FOR BEING SPACED AT A DISTANCE THEREFROM, CONDUCTORS CONNECTING SAID MEASURING AND MONITORING MEANS AND SAID DETECTOR MEANS AND FEEDING VOLTAGE AND CURRENT TO THE DETECTOR MEANS AND TRANSMITTING TO THE MEASURING AND MONITORING MEANS INFORMATION OBTAINED BY THE DETECTOR MEANS, SAID MEASURING AND MONITORING MEANS INCLUDING A SUPPLY SOURCE FOR FEEDING DIRECT CURRENT TO THE DETECTOR MEANS AND INCLUDING A CONTROL CIRCUIT COUPLED TO AND OPERABLE TO MAINTAIN A CONSTANT VOLTAGE AT THE DETECTOR MEANS, SAID DETECTOR MEANS INCLUDING SENSING ELEMENTS ADAPTED TO GENERATE A MEASUREMENT SIGNAL IN THE FORM OF A DIRECT VOLTAGE, AND A SERVO-CONTROLLED FLOATING GROUND CONNECTED TO SAID MEASURING AND MONITORING MEANS AND CONTROLLED AT LEAST IN PART THEREBY TO PROVIDE FOR SAID MEASURING AND MONITORING MEANS A REFERENCE POTENTIAL WHICH IS CONTROLLED TO BE AT LEAST SUBSTANTIALLY EQUAL TO THE VOLTAGE APPLIED TO THE DETECTOR MEANS.
Claim 2
Dependent Claim
174 words
AN ELECTRICAL APPARATUS FOR MEASURING AND MONITORING A PARAMETER, COMPRISING MEASURING AND MONITORING MEANS FOR GENERATING A MEASUREMENT SIGNAL, DETECTOR MEANS ADAPTED FOR CONNECTION TO SAID MEASURING AND MONITORING MEANS AND ADAPTED FOR BEING SPACED AT A DISTANCE THEREFROM, CONDUCTORS CONNECTING SAID MEASURING AND MONITORING MEANS AND SAID DETECTOR MEANS AND FEEDING VOLTAGE AND CURRENT TO THE DETECTOR MEANS AND TRANSMITTING TO THE MEASURING AND MONITORING MEANS INFORMATION OBTAINED BY THE DETECTOR MEANS, SAID MEASURING AND MONITORING MEANS INCLUDING A SUPPLY SOURCE FOR FEEDING DIRECT CURRENT TO THE DETECTOR MEANS AND INCLUDING A CONTROL CIRCUIT COUPLED TO AND OPERABLE TO MAINTAIN A CONSTANT VOLTAGE AT THE DETECTOR MEANS, SAID DETECTOR MEANS INCLUDING SENSING ELEMENTS ADAPTED TO GENERATE A MEASUREMENT SIGNAL IN THE FORM OF A DIRECT VOLTAGE, AND A SERVO-CONTROLLED FLOATING GROUND CONNECTED TO SAID MEASURING AND MONITORING MEANS AND CONTROLLED AT LEAST IN PART THEREBY TO PROVIDE FOR SAID MEASURING AND MONITORING MEANS A REFERENCE POTENTIAL WHICH IS CONTROLLED TO BE AT LEAST SUBSTANTIALLY EQUAL TO THE VOLTAGE APPLIED TO THE DETECTOR MEANS.
Claim 3
Dependent Claim
174 words
An electrical apparatus for measuring and monitoring a parameter, comprising measuring and monitoring means for generating a measurement signal, detector means adapted for connection to said measuring and monitoring means and adapted for being spaced at a distance therefrom, conductors connecting said measuring and monitoring means and said detector means and feeding voltage and current to the detector means and transmitting to the measuring and monitoring means information obtained by the detector means, said measuring and monitoring means including a supply source for feeding direct current to the detector means and including a control circuit coupled to and operable to maintain a constant voltage at the detector means, said detector means including sensing elements adapted to generate a measurement signal in the form of a direct voltage, and a servo-controlled floating ground connected to said measuring and monitoring means and controlled at least in part thereby to provide for said measuring and monitoring means a reference potential which is controlled to be at least substantially equal to the voltage applied to the detector means.
Claim 4
Dependent Claim
174 words
An electrical apparatus for measuring and monitoring a parameter, comprising measuring and monitoring means for generating a measurement signal, detector means adapted for connection to said measuring and monitoring means and adapted for being spaced at a distance therefrom, conductors connecting said measuring and monitoring means and said detector means and feeding voltage and current to the detector means and transmitting to the measuring and monitoring means information obtained by the detector means, said measuring and monitoring means including a supply source for feeding direct current to the detector means and including a control circuit coupled to and operable to maintain a constant voltage at the detector means, said detector means including sensing elements adapted to generate a measurement signal in the form of a direct voltage, and a servo-controlled floating ground connected to said measuring and monitoring means and controlled at least in part thereby to provide for said measuring and monitoring means a reference potential which is controlled to be at least substantially equal to the voltage applied to the detector means.
Claim 5
Dependent Claim
158 words
A measuring and monitoring apparatus according to claim 1, comprising an emitter-follower circuit having a high input impedance, the control circuit being connected to said floating ground and to said supply source of the detector means, said detector means including a supply output connected firstly to ground and secondly to the floating ground by means of said emitter-follower circuit, said detector means including a supply input, the control circuit comprising a circuit having a high impedance input and an auxiliary conductor connecting the same to the supply input of the detector to servo-control the potential of the said supply input in relation to the floating ground so as to keep it equal to a reference potential kept constant in relation to the potential of the floating ground, and a load circuit means which receives the measurement signal from said measuring and monitoring means, said load circuit means having as a reference potential the potential of the floating ground.
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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |