Patent US5470484A successfully refreshed from Google Patents.
US5470484A
Expired / Lapsed
US
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Method and apparatus for controlling the feed of water treatment chemicals using a voltammetric sensor
Assignee: Buckman Laboratories International Inc
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Filing: 1994-01-13
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Granted: 1995-11-28
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Expires: 2014-01-13
Abstract
Abstract A method for controlling the chemical treatment of a solution comprises the steps of feeding a treatment chemical into the solution, applying an external voltage across a reference electrode and a working electrode of a voltammetric sensor while the electrodes are immersed in the solution, measuring a current that flows through the working electrode, converting the measured current into a feedback signal indicative of the concentration of treatment chemical in the solution, and using the feedback signal to control the rate of feeding the treatment chemical.
Inventors
- 👤 Thomas E. McNeel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:47
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N27/00; G01N27/26; G01N27/416; G01N27/49
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
109 words
A method for controlling the chemical treatment of a solution comprising the steps of: (a) feeding a treatment chemical into the solution to obtain a mixture of the treatment chemical and the solution; (b) applying an external voltage across a reference electrode and a working electrode of a voltammetric sensor while the electrodes are immersed in and contact the mixture; (c) measuring a current that flows through the working electrode; (d) converting the measured current into a feedback signal which is indicative of a concentration of a substance in the mixture; and (e) using the feedback signal to control a rate of feeding the treatment chemical in step (a).
Claim 2
Independent Claim
109 words
A method for controlling the chemical treatment of a solution comprising the steps of: (a) feeding a treatment chemical into the solution to obtain a mixture of the treatment chemical and the solution; (b) applying an external voltage across a reference electrode and a working electrode of a voltammetric sensor while the electrodes are immersed in and contact the mixture; (c) measuring a current that flows through the working electrode; (d) converting the measured current into a feedback signal which is indicative of a concentration of a substance in the mixture; and (e) using the feedback signal to control a rate of feeding the treatment chemical in step (a).
Claim 3
Dependent Claim
40 words
The method according to claim 1, wherein using the feedback signal in step (e) comprises comparing the feedback signal and a reference signal to generate a control signal for controlling the rate of feeding the treatment chemical in step (a).
Claim 4
Dependent Claim
18 words
The method according to claim 1, wherein applying an external voltage step (b) comprises applying a d.c. voltage.
Claim 5
Dependent Claim
19 words
The method according to claim 1, wherein applying an external voltage step (b) comprises applying a voltage pulse train.
Claim 6
Dependent Claim
32 words
The method according to claim 4, wherein measuring a current in step (c) comprises measuring the current after the application of a voltage pulse of the pulse train to permit non-faradaic charging.
Claim 7
Dependent Claim
27 words
The method according to claim 1, further comprising the step of: (f) applying a current to the working electrode sufficient to remove deposits from the working electrode.
Claim 8
Dependent Claim
43 words
The method according to claim 1, further comprising the steps of: measuring a background signal before the treatment chemical is introduced into the solution; and subtracting the background signal from the feedback signal after the treatment chemical has been introduced into the solution.
Claim 9
Independent Claim
124 words
An apparatus for controlling the amount of treatment chemicals to be added to a solution, comprising: means for feeding a treatment chemical into the solution to obtain a mixture of the treatment chemical and the solution; a voltammetric sensor including: a reference electrode, a working electrode, means for applying a voltage across the reference electrode and working electrode while the electrodes are immersed in and contact the mixture, means for measuring a current that flows through the working electrode, and means for converting the measured current into a feedback signal which is indicative of a concentration of a substance in the mixture; and means for applying the feedback signal to the feeding means so as to control a rate of feeding the treatment chemical.
Claim 10
Independent Claim
124 words
An apparatus for controlling the amount of treatment chemicals to be added to a solution, comprising: means for feeding a treatment chemical into the solution to obtain a mixture of the treatment chemical and the solution; a voltammetric sensor including: a reference electrode, a working electrode, means for applying a voltage across the reference electrode and working electrode while the electrodes are immersed in and contact the mixture, means for measuring a current that flows through the working electrode, and means for converting the measured current into a feedback signal which is indicative of a concentration of a substance in the mixture; and means for applying the feedback signal to the feeding means so as to control a rate of feeding the treatment chemical.
Claim 11
Dependent Claim
39 words
The apparatus according to claim 8, further comprising means for comparing the feedback signal with a reference signal to generate a control signal to the feeding means for controlling the rate of feeding the treatment chemical into the solution.
Claim 12
Dependent Claim
25 words
The apparatus according to claim 8, further comprising: means for applying a current to the working electrode sufficient to remove deposits from the working electrode.
Claim 13
Dependent Claim
44 words
The apparatus according to claim 8, further comprising: means for measuring a background signal before the treatment chemical is introduced into the solution; and means for subtracting the background signal from the feedback signal after the treatment chemical has been introduced into the solution.
Claim 14
Independent Claim
130 words
A method for controlling the chemical treatment of a solution comprising the steps of: (a) feeding a treatment chemical into the solution to obtain a mixture of the treatment chemical and the solution; (b) applying an external voltage across a counter electrode and a working electrode of a voltammetric sensor while the electrodes are immersed in and contact the mixture; (c) maintaining a voltage between a reference electrode of the voltammetric sensor and the working electrode at a desired voltage level; (d) measuring a current that flows through the working electrode; (e) converting the measured current into a feedback signal which is indicative of a concentration of a substance in the mixture; and (f) using the feedback signal to control a rate of feeding the treatment chemical in step (a).
Claim 15
Independent Claim
130 words
A method for controlling the chemical treatment of a solution comprising the steps of: (a) feeding a treatment chemical into the solution to obtain a mixture of the treatment chemical and the solution; (b) applying an external voltage across a counter electrode and a working electrode of a voltammetric sensor while the electrodes are immersed in and contact the mixture; (c) maintaining a voltage between a reference electrode of the voltammetric sensor and the working electrode at a desired voltage level; (d) measuring a current that flows through the working electrode; (e) converting the measured current into a feedback signal which is indicative of a concentration of a substance in the mixture; and (f) using the feedback signal to control a rate of feeding the treatment chemical in step (a).
Claim 16
Dependent Claim
18 words
The method according to claim 12, wherein applying an external voltage step (b) comprises applying a d.c. voltage.
Claim 17
Dependent Claim
19 words
The method according to claim 12, wherein applying an external voltage step (b) comprises applying a voltage pulse train.
Claim 18
Dependent Claim
36 words
The method according to claim 14, wherein measuring a current in step (b) comprises measuring the current after the application of a voltage pulse of the pulse train to permit a non-faradaic charging current to decay.
Claim 19
Dependent Claim
27 words
The method according to claim 12, further comprising the step of: (g) applying a current to the working electrode sufficient to remove deposits from the working electrode.
Claim 20
Dependent Claim
43 words
The method according to claim 12, further comprising the steps of: measuring a background signal before the treatment chemical is introduced into the solution; and subtracting the background signal from the feedback signal after the treatment chemical has been introduced into the solution.
Claim 21
Independent Claim
148 words
An apparatus for producing a feedback signal in a system for controlling the amount of treatment chemicals to be added to a solution, comprising: means for feeding treatment chemicals into the solution to obtain a mixture of the treatment chemicals and the solution; a voltammetric sensor including: a reference electrode, a working electrode, a counter electrode, means for applying an external voltage across the counter electrode and working electrode while the electrodes are immersed in and contact the mixture, means for maintaining a voltage between the reference electrode and working electrode at a desired voltage, means for measuring a current that flows through the working electrode, and means for converting the measured current into a feedback signal which is indicative of the concentration of a substance in the mixture; and means for using the feedback signal to control a rate of feeding the treatment chemicals in the solution.
Claim 22
Independent Claim
148 words
An apparatus for producing a feedback signal in a system for controlling the amount of treatment chemicals to be added to a solution, comprising: means for feeding treatment chemicals into the solution to obtain a mixture of the treatment chemicals and the solution; a voltammetric sensor including: a reference electrode, a working electrode, a counter electrode, means for applying an external voltage across the counter electrode and working electrode while the electrodes are immersed in and contact the mixture, means for maintaining a voltage between the reference electrode and working electrode at a desired voltage, means for measuring a current that flows through the working electrode, and means for converting the measured current into a feedback signal which is indicative of the concentration of a substance in the mixture; and means for using the feedback signal to control a rate of feeding the treatment chemicals in the solution.
Claim 23
Dependent Claim
25 words
The apparatus according to claim 18, further comprising means for applying a current to the working electrode sufficient to remove deposits from the working electrode.
Claim 24
Dependent Claim
44 words
The apparatus according to claim 18, further comprising: means for measuring a background signal before the treatment chemicals are introduced into the solution; and means for subtracting the background signal from the feedback signal after the treatment chemical have been introduced into the solution.
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