Patent US5278074A successfully refreshed from Google Patents.
US5278074A
Expired / Lapsed
US
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Method of monitoring and controlling corrosion inhibitor dosage in aqueous systems
Assignee: Ecolab USA Inc
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Filing: 1992-04-22
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Granted: 1994-01-11
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Expires: 2012-04-22
Abstract
Abstract The concentration of an aromatic azole corrosion inhibitor in the water of an aqueous system is monitored by a fluorometric method which is based upon the measurement of the fluorescence intensity of the aromatic azole corrosion inhibitor itself, and the precise determination of concentration permits control of the dosage of such aromatic azole corrosion inhibitor.
Inventors
- 👤 Narasimha M. Rao
- 👤 Frank F.-Y. Lu
- 👤 John E. Hoots
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:29
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N33/00; G01N33/18; G01N33/1826; Y; Y02; Y02A; Y02A20/00; Y02A20/20; Y10; Y10S; Y10S436/00; Y10S436/815; Y10T; Y10T436/00; Y10T436/11; Y10T436/117497; Y10T436/14; Y10T436/141111; Y10T436/145555; Y10T436/147777; Y10T436/25
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
134 words
A method for controlling the concentration of an aromatic azole corrosion inhibitor in the water of an industrial aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity; wherein said measuring is conducted on a substantially continuous basis; and adding to said aqueous system a sufficient amount of said aromatic azole to provide a desired total concentration of said aromatic azole in said aqueous system.
Claim 2
Independent Claim
134 words
A method for controlling the concentration of an aromatic azole corrosion inhibitor in the water of an industrial aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity; wherein said measuring is conducted on a substantially continuous basis; and adding to said aqueous system a sufficient amount of said aromatic azole to provide a desired total concentration of said aromatic azole in said aqueous system.
Claim 3
Dependent Claim
42 words
The method of claim 1 further including the step of adjusting the pH of said sample prior to said fluorescing of said sample, wherein said pH is adjusted by the addition of a mineral acid to a pH of less than 1.5.
Claim 4
Dependent Claim
33 words
The method of claim 1 wherein said water has a pH within the range of from about 4 to about 9, and said fluorescing is conducted at excitation/emission wavelengths of about 285/350 nm.
Claim 5
Dependent Claim
38 words
The method of claim 1 wherein said aromatic azole is tolyltriazole or butylbenzotriazole, said water has a pH of less than about a pH of 1.5, and said fluorescing is conducted at excitation/emission wavelengths of about 280/410 nm.
Claim 6
Dependent Claim
33 words
The method of claim 1 wherein said aromatic azole is benzotriazole, said water has a pH of less than about 1.5, and said fluorescing is conducted at excitation/emission wavelengths of about 280/390 nm.
Claim 7
Dependent Claim
38 words
The method of claim 1 wherein said aromatic azole is naphthotriazole, said water has a pH within the range of from about 4 to about 11, and said fluorescing is conducted at excitation/emission wavelengths of about 363/445 nm.
Claim 8
Dependent Claim
103 words
The method of claim 1 further wherein; said water and said sample of said water contain an inert fluorescent tracer; said measuring of the fluorescence intensity of said sample also includes the measuring of the contribution to said fluorescence intensity from said inert tracer; the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer is also determined; and the system demand for said aromatic azole is determined from the difference between the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer and said aromatic azole concentration based its said fluorescence intensity.
Claim 9
Independent Claim
99 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an industrial aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, and whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity.
Claim 10
Independent Claim
99 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an industrial aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, and whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity.
Claim 11
Dependent Claim
37 words
The method of claim 8 further including the step of adjusting the pH of said sample by the addition of a mineral acid to a pH of less than 1.5 prior to said fluorescing of said sample.
Claim 12
Dependent Claim
33 words
The method of claim 8 wherein said water has a pH within the range of from about 4 to about 9, and said fluorescing is conducted at excitation/emission wavelengths of about 285/350 nm.
Claim 13
Dependent Claim
38 words
The method of claim 8 wherein said aromatic azole is tolyltriazole or butylbenzotriazole, said water has a pH of less than about a pH of 1.5, and said fluorescing is conducted at excitation/emission wavelengths of about 280/410 nm.
Claim 14
Dependent Claim
33 words
The method of claim 8 wherein said aromatic azole is benzotriazole, said water has a pH of less than about 1.5, and said fluorescing is conducted at excitation/emission wavelengths of about 280/390 nm.
Claim 15
Dependent Claim
38 words
The method of claim 8 wherein said aromatic azole is naphthotriazole, said water has a pH within the range of from about 4 to about 11, and said fluorescing is conducted at excitation/emission wavelengths of about 363/445 nm.
Claim 16
Dependent Claim
23 words
The method of claim 8 wherein said fluorescing, said comparing and said determination of aromatic azole concentration are conducted on a continuous basis.
Claim 17
Dependent Claim
26 words
The method of claim 8 wherein said industrial aqueous system is an industrial steam-generating water system, a cooling water system or a manufacturing process water system.
Claim 18
Dependent Claim
104 words
The method of claim 8 further wherein; said water and said sample of said water contain an inert fluorescent tracer; said measuring of the fluorescence intensity of said sample also includes the measuring of the contribution to said fluorescence intensity from said inert tracer; the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer is also determined; and the system demand for said aromatic azole is determined from the difference between the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer and said aromatic azole concentration based on its said fluorescence intensity.
Claim 19
Independent Claim
127 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an industrial aqueous system, comprising: sampling the water of an industrial aqueous system by isolating a sample of said water from said aqueous system; fluorescing said sample; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, and whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity, wherein said sampling, said fluorescing and said concentration determination are conducted on a substantially continuous basis.
Claim 20
Independent Claim
127 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an industrial aqueous system, comprising: sampling the water of an industrial aqueous system by isolating a sample of said water from said aqueous system; fluorescing said sample; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, and whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity, wherein said sampling, said fluorescing and said concentration determination are conducted on a substantially continuous basis.
Claim 21
Dependent Claim
38 words
The method of claim 17 wherein said sample is adjusted by the addition of a mineral acid to a pH of less than about 1.5 prior to said fluorescing, and said aromatic azole is tolyltriazole, butylbenzotriazole or benzotriazole.
Claim 22
Independent Claim
197 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity, and further wherein: said water and said sample of said water contain an inert fluorescent tracer; said measuring of the fluorescence intensity of said sample also includes the measuring of the contribution to said fluorescence intensity from said inert tracer; the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer is also determined; and the system demand for said aromatic azole is determined from the difference between the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer and said aromatic azole concentration based on its said fluorescence intensity.
Claim 23
Independent Claim
197 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, whereby the concentration of said aromatic azole is determined by correlation to its fluorescence intensity, and further wherein: said water and said sample of said water contain an inert fluorescent tracer; said measuring of the fluorescence intensity of said sample also includes the measuring of the contribution to said fluorescence intensity from said inert tracer; the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer is also determined; and the system demand for said aromatic azole is determined from the difference between the aromatic azole concentration based on the contribution to said fluorescence intensity from said inert tracer and said aromatic azole concentration based on its said fluorescence intensity.
Claim 24
Independent Claim
123 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, wherein the concentration of said aromatic azole is determined by correlation to its fluorescence intensity, and further wherein said sample is adjusted by the addition of a mineral acid to a pH of less than about 1.5 prior to said fluorescing.
Claim 25
Independent Claim
123 words
A method for monitoring the concentration of an aromatic azole corrosion inhibitor in the water of an aqueous system, comprising: fluorescing a sample of said water from said aqueous system; measuring the fluorescence intensity of said sample; and comparing said fluorescence intensity to a curve from a plot of known concentrations of said aromatic azole in aqueous solutions versus the fluorescence intensities of said solutions, wherein the fluorescence excitation/emission wavelengths and the pH domain of said plot and said sample are comparable, wherein the concentration of said aromatic azole is determined by correlation to its fluorescence intensity, and further wherein said sample is adjusted by the addition of a mineral acid to a pH of less than about 1.5 prior to said fluorescing.
Claim 26
Dependent Claim
14 words
The method of claim 20 wherein said aromatic azole is tolyltriazole, butylbenzotriazole or benzotriazole.
Claim 27
Dependent Claim
16 words
The method of claim 20 wherein said monitoring is conducted on a substantially on-line continuous basis.
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