US3821642A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion measuring bridge circuit having automatic controlled constant source of energy and temperature compensation
Assignee: ITHACO
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Filing: 1972-11-30
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Granted: 1974-06-28
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Expires: 1992-11-30
Abstract
Abstract A controllable source of alternating current signals, for excitation of a bridge circuit used in apparatus such as corrosion analyzers and the like, includes an automatic amplitude control circuit to maintain the amplitude of the alternating current signals applied to the bridge circuit substantially constant for wide variations in the impedance of the bridge circuit. By maintaining the bridge circuit excitation substantially constant, the amplitude of the bridge circuit unbalance signals now provides an accurate indication bridge circuit unbalance and therefor the corrosion of a probe element connected in the bridge circuit.
Inventors
- 👤 E Seymour
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:14
CPC Classifications
G; G01; G01R; G01R17/00; G01R17/10; G01R17/105; G01N; G01N17/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
175 words
A corrosion analyzer for use with a corrosion probe, the elements of which are connected to a bridge circuit, said corrosion analyzer comprising: a controllable source of alternating current signals connected to apply alternating current signals across a pair of opposite junctions of the bridge circuit, said controllable source being responsive to a control signal applied thereto to control the amplitude of the alternating current signals applied to the bridge circuit; amplitude control means, connected between said opposite junctions of said bridge circuit and said source, responsive to the amplitude of alternating current signals applied to said opposite junctions to apply said control signal to said source to maintain the amplitude of the alternating current signals across said pair of opposite junctions of the bridge circuit substantially constant, and circuit means for converting the alternating current signals developed across another pair of bridge circuit junctions opposite those connected to said source to an output signal that is a function of bridge circuit unbalance as a result of the corrosion of an element of said probe.
Claim 2
Dependent Claim
175 words
A corrosion analyzer for use with a corrosion probe, the elements of which are connected to a bridge circuit, said corrosion analyzer comprising: a controllable source of alternating current signals connected to apply alternating current signals across a pair of opposite junctions of the bridge circuit, said controllable source being responsive to a control signal applied thereto to control the amplitude of the alternating current signals applied to the bridge circuit; amplitude control means, connected between said opposite junctions of said bridge circuit and said source, responsive to the amplitude of alternating current signals applied to said opposite junctions to apply said control signal to said source to maintain the amplitude of the alternating current signals across said pair of opposite junctions of the bridge circuit substantially constant, and circuit means for converting the alternating current signals developed across another pair of bridge circuit junctions opposite those connected to said source to an output signal that is a function of bridge circuit unbalance as a result of the corrosion of an element of said probe.
Claim 3
Dependent Claim
33 words
A corrosion analyzer as defined in claim 1 wherein: said controllable source is a oscillator circuit that is response to a direct current control signal applied thereto to control the amplitude of oscillation.
Claim 4
Dependent Claim
50 words
A corrosion analyzer as defined in claim 2 wherein said amplitude control means includes: detection circuit means for detecting the alternating current signals applied to the bridge circuit to produce said direct current control signal, the magnitude of which, is a function of the amplitude of the alternating current signals.
Claim 5
Dependent Claim
51 words
A corrosion analyzer as defined in claim 3 wherein said amplitude control means includes: circuit means for providing a direct current reference signal, and a summing circuit summing the direct current reference signal with a detected direct current signal from the detection circuit means to produce said direct current control signal.
Claim 6
Dependent Claim
63 words
A corrosion analyzer as defined in claim 4 wherein: said oscillator is a push-pull semiconductor oscillator circuit connected to drive the primary winding of a transformer, the secondary winding of which is, connected to the bridge circuit, and wherein said direct circuit control signal is applied to a center tap of said primary winding to apply an energization potential to the oscillator circuit.
Claim 7
Dependent Claim
79 words
A corrosion analyzer as deFined in claim 5 wherein said conversion circuit means includes: a narrow bandwidth tuned amplifier, tuned to the output frequency of the oscillator, and connected to receive input signals from said another pair of bridge circuit junctions, a synchronous detector circuit, connected to receive reference signals having the frequency of said oscillator signals for detecting the output signals from said tuned amplifier, and an integrating circuit connected to the output of said synchronous detector circuit.
Claim 8
Independent Claim
111 words
A method of measuring corrosion comprising the steps of: inserting an electrically conductive element in a corrosive medium wherein the corrosion of the element changes its impedance; connecting said element in a bridge circuit; applying electrical energization signals to a first pair of opposite junctions of the bridge circuit in a manner so that magnitude of the energization signals applied thereto remains substantially constant for variations in bridge circuit impedance due to temperature variations and bridge circuit unbalance, and converting the amplitude of the unbalance signals of said bridge circuit across a second pair of bridge junctions, opposite said first pairs of junctions, into an indication of corrosion of said element.
Claim 9
Independent Claim
111 words
A method of measuring corrosion comprising the steps of: inserting an electrically conductive element in a corrosive medium wherein the corrosion of the element changes its impedance; connecting said element in a bridge circuit; applying electrical energization signals to a first pair of opposite junctions of the bridge circuit in a manner so that magnitude of the energization signals applied thereto remains substantially constant for variations in bridge circuit impedance due to temperature variations and bridge circuit unbalance, and converting the amplitude of the unbalance signals of said bridge circuit across a second pair of bridge junctions, opposite said first pairs of junctions, into an indication of corrosion of said element.
Claim 10
Dependent Claim
100 words
A method as defined in claim 7 wherein said applying step includes: providing a controllable source of energization signals, the magnitude of which is a function of a control signal applied thereto; applying signals from said source across said first pair of junctions for energizing said bridge circuit; detecting the magnitude of the energization signals applied across said first pair of junctions to provide a control signal, and applying said control signal to said controllable source so that the magnitude of the energization signal applied across said first pair of junctions remains substantially constant for variations in bridge circuit impedance.
Claim 11
Dependent Claim
41 words
A method as defined in claim 8 wherein: said applying step applies alternating current energization signals, and said converting step converts the alternating current unbalance signals into a direct current signal that is a function of the corrosion of said element.
Claim 12
Dependent Claim
54 words
A method as defined in claim 9 wherein said converting step includes: transmitting a narrow band of signals frequencies centered about said alternating current energization signals, and synchronously detecting the narrow band of signal frequencies to produce a direct current signal, the magnitude of which is an indication of the corrosion of said element.
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) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |