US3848187A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of detecting the onset of formation of adherent precipitates on surfaces immersed in liquids, and of controlling the formation of such precipitates
Assignee: ROHRBACK Corp A WASHINGTON CORP
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Filing: 1973-02-26
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Granted: 1974-11-12
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Expires: 1993-02-26
Abstract
Abstract The method comprises employing electrical contact resistance to sense whether or not there is incipient precipitation of adherent scale, paraffin wax, etc., on surfaces immersed in various liquids. The method is surprisingly sensitive, and otherwise effective, even when the liquids are electrically conductive. The method further comprises performing certain steps relative to the submerged surfaces, and/or relative to the liquids, in order to control precipitate formation. The selection of polarity, materials, etc., is caused to be such that sensitivity is maximized, and electrolytic dissolution of the submerged elements is minimized.
Inventors
- 👤 G Rohrback
- 👤 E Holmes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:24
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01B; G01B7/00; G01B7/02; G01B7/06; G01N27/041; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2499
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
152 words
A method of detecting the deposition, onto a surface, of adherent scale or other adherent substance, which method comprises the steps of: a. exposing an electrically conductive surface to a liquid of a type which, under at least some conditions, will deposit at least a partial coating onto a surface exposed to said liquid, b. detecting an increase in the electrical contact resistance at said surface after it has been thus exposed, said detection of said increase in electrical contact resistance including the step of engaging with said surface a contact element and determining the electrical contact resistance between said surface and said contact element, said increase in electrical contact resistance indicating that adherent substance has deposited from said liquid onto at least part of said surface, and c. employing said detected increase in electrical contact resistance as an indication of the deposition of adherent substance from said liquid onto said surface.
Claim 2
Independent Claim
152 words
A method of detecting the deposition, onto a surface, of adherent scale or other adherent substance, which method comprises the steps of: a. exposing an electrically conductive surface to a liquid of a type which, under at least some conditions, will deposit at least a partial coating onto a surface exposed to said liquid, b. detecting an increase in the electrical contact resistance at said surface after it has been thus exposed, said detection of said increase in electrical contact resistance including the step of engaging with said surface a contact element and determining the electrical contact resistance between said surface and said contact element, said increase in electrical contact resistance indicating that adherent substance has deposited from said liquid onto at least part of said surface, and c. employing said detected increase in electrical contact resistance as an indication of the deposition of adherent substance from said liquid onto said surface.
Claim 3
Dependent Claim
14 words
The invention as claimed in claim 1, in which said liquid is electrically conductive.
Claim 4
Dependent Claim
13 words
The invention as claimed in claim 2, in which said liquid is aqueous.
Claim 5
Dependent Claim
45 words
The invention as claimed in claim 3, in which said aqueous liquid is one which, under at least some conditions, will deposit onto a surface exposed Thereto a coating forming part of a class consisting of alkaline earth metal carbonates and alkaline earth metal sulfates.
Claim 6
Dependent Claim
14 words
The invention as claimed in claim 1, in which said liquid is electrically insulating.
Claim 7
Dependent Claim
13 words
The invention as claimed in claim 5, in which said liquid is organic.
Claim 8
Dependent Claim
49 words
The invention as claimed in claim 1, in which said method further comprises effecting said determination of contact resistance by generating a DC voltage drop between said surface and said contact element, and noting a change in said voltage drop due to deposition of adherent substance onto said surface.
Claim 9
Dependent Claim
58 words
The invention as claimed in claim 7, in which said liquid is electrically conductive, and in which said method further comprises so selecting the material forming said surface that a significant overvoltage effect results from separation of said surface from said contact elements due to deposition of at least a partial coating of said substance onto said surface.
Claim 10
Dependent Claim
33 words
The invention as claimed in claim 8, in which said method further comprises selecting said material forming said surface from a class consisting of carbon, graphite, stainless steel, nickel alloys, palladium and platinum.
Claim 11
Dependent Claim
34 words
The invention as claimed in claim 1, in which said method comprises effecting said determination of electrical contact resistance between said surface and said contact element while said surface remains exposed to said liquid.
Claim 12
Dependent Claim
45 words
The invention as claimed in claim 1, in which said method further comprises effecting said detection of electrical contact resistance increased by repeatedly effecting said determination of electrical contact resistance between said surface and said contact element while said surface is exposed to said liquid.
Claim 13
Dependent Claim
37 words
The invention as claimed in claim 1, in which said method further comprises the step of correlating the contact resistance increase at said test surface to the deposition of substance on exposed surfaces in an industrial system.
Claim 14
Dependent Claim
29 words
The invention as claimed in claim 12, in which said method further comprises causing said liquid to be substantially the same as the liquid present in said industrial system.
Claim 15
Independent Claim
218 words
A method of detecting the onset of formation of adherent precipitates on surfaces immersed in liquids, which comprises the steps of: a. immersing electrically conductive test surface means and electrically conductive auxiliary contactor means in a liquid, said liquid being of a type which, under, at least, some conditions, will deposit an adherent precipitate onto test surface means immersed therein, b. causing said auxiliary contactor means to be in engagement with said test surface means while both are thus immersed in said liquid, c. determining the electrical contact resistance between the thus engaged and immersed test surface means and contactor means, d. effecting relative movement between said test surface means and contactor means, e. subsequently redetermining the electrical contact resistance between said test surface means and contactor means while the same are engaged with each other and immersed in said liquid, whereby deposition of, at least, nuclei of adherent precipitate on said test surface means will cause said contactor means to be spaced from said test surface means by a distance related to the thickness of said adherent precipitate, to thereby increase the contact resistance therebetween, and f. employing the increase, or lack of increase, of said contact resistance as an indication of the formation, or lack of formation, of significant adherent precipitate on said test surface means.
Claim 16
Independent Claim
218 words
A method of detecting the onset of formation of adherent precipitates on surfaces immersed in liquids, which comprises the steps of: a. immersing electrically conductive test surface means and electrically conductive auxiliary contactor means in a liquid, said liquid being of a type which, under, at least, some conditions, will deposit an adherent precipitate onto test surface means immersed therein, b. causing said auxiliary contactor means to be in engagement with said test surface means while both are thus immersed in said liquid, c. determining the electrical contact resistance between the thus engaged and immersed test surface means and contactor means, d. effecting relative movement between said test surface means and contactor means, e. subsequently redetermining the electrical contact resistance between said test surface means and contactor means while the same are engaged with each other and immersed in said liquid, whereby deposition of, at least, nuclei of adherent precipitate on said test surface means will cause said contactor means to be spaced from said test surface means by a distance related to the thickness of said adherent precipitate, to thereby increase the contact resistance therebetween, and f. employing the increase, or lack of increase, of said contact resistance as an indication of the formation, or lack of formation, of significant adherent precipitate on said test surface means.
Claim 17
Dependent Claim
49 words
The invention as claimed in claim 14, in which said method further comprises determining said contact resistance by connecting a current source to said test surface means and said contactor means, and sensing the voltage drop present between engaged regions of said test surface means and said contactor means.
Claim 18
Dependent Claim
50 words
The invention as claimed in claim 14, in which said metHod further comprises determining said contact resistance by connecting a DC source to said test surface means and said contactor means, and sensing the DC voltage drop present between the engaged regions of said test surface means and contactor means.
Claim 19
Dependent Claim
55 words
The invention as claimed in claim 16, in which said liquid is electrically conductive, and said method further comprises so selecting the material forming at least one of said test surface means and contactor means that a major overvoltage effect results in response to said spacing, whereby to increase greatly the sensitivity of the method.
Claim 20
Dependent Claim
38 words
The invention as claimed in claim 17, in which at least one of said test surface means and said contactor means is selected from a class consisting of carbon, graphite, stainless steel, nickel alloys, palladium, platinum and mercury.
Claim 21
Dependent Claim
36 words
The invention as claimed in claim 14, in which said relative movement recited in step (d) is such as to cause different portions of said test surface means to be engaged sequentially by said contactor means.
Claim 22
Dependent Claim
53 words
The invention as claimed in claim 14, in which said step (c) is performed while said test surface means and said contactor means are sufficiently free of adherent precipitate that there is an electronic conduction path therebetween, whereby said spacing effects breaking of said electronic path and thus greatly increases the contact resistance.
Claim 23
Dependent Claim
47 words
The invention as claimed in claim 14, in which said liquid is selected from those aqueous solutions which will, under st least some conditions, precipitate onto said test surface means adherent coatings selected from a class consisting of alkaline earth metal carbonates and alkaline earth metal sulfates.
Claim 24
Dependent Claim
24 words
The invention as claimed in claim 14, in which said liquid is selected from a class consisting of petroleum and liquid products of petroleum.
Claim 25
Dependent Claim
55 words
The invention as claimed in claim 14, in which said method further comprises the steps of causing said liquid to be substantially the same as the liquid present in an industrial system, and correlating the contact resistance increase at said test surface means to the deposition of adherent precipitate on surfaces in said industrial system.
Claim 26
Dependent Claim
49 words
The invention as claimed in claim 14, in which said method further comprises causing said engagement between said test surface means and said contactor means to be such that any adherent precipitate present on the engaged portion of said test surface means will not be substantially penetrated or removed.
Claim 27
Dependent Claim
33 words
The invention as claimed in claim 14, in which said method further comprises effecting said relative movement by separating said contactor means from said test surface means, and then bringing the same together.
Claim 28
Dependent Claim
36 words
The invention as claimed in claim 25, in which said contactor means is moved substantially perpendicularly to said test surface means, whereby to prevent substantial rubbing or scraping of adherent precipitate on said test surface means.
Claim 29
Dependent Claim
32 words
The invention as claimed in claim 14, in which said method further comprises effecting said relative movement by causing rolling contact to occur between said test surface means and said contactor means.
Claim 30
Dependent Claim
38 words
The invention as claimed in claim 14, in which said method further comprises effecting cleaning of said test surface means to an extent sufficient that electronic conduction will occur between said test surface means and said contactor means.
Claim 31
Dependent Claim
31 words
The invention as claimed in claim 28, in which said method further comprises effecting said cleaning after each occurrence of the formation of significant adherent precipitate on said test surface means.
Claim 32
Dependent Claim
61 words
The invention as claimed in claim 14, in which said method further comprises causing said liquid to be electrically conductive, and causing both said test surface means and said contactor means to be cathodic relative to an auxiliary anode electrode means which is in contact with said liquid, whereby to minimize electrolytic dissolution of said test surface means and contactor means.
Claim 33
Dependent Claim
71 words
The invention as claimed in claim 30, in which said method further comprises effecting said determination of contact resistance by connecting said test surface means through an external DC source to said anode electrode means, and connecting a voltage sensing means to said test surface means and to said contactor means, whereby said contactor means serves as a potential tap and conducts little or no current to said voltage sensing means.
Claim 34
Independent Claim
118 words
A method of effecting testing relative to the scale forming tendencies of an aqueous system, which comprises: a. immersing an electrically conductive test surface in an electrically conductive aqueous liquid, b. bringing an auxiliary electrode into electrical contact with said liquid, c. impressing a DC current source between said test surface and said electrode, the polarity of said source being such that said test surface has a predetermined polarity relative to said electrode, and d. sensing whether or not significant scale is precipitating out of said liquid and adhering to said test surface, said last-named step being performed by detecting any increase in the electrical contact resistance between said test surface and a contact element in engagement therewith.
Claim 35
Independent Claim
118 words
A method of effecting testing relative to the scale forming tendencies of an aqueous system, which comprises: a. immersing an electrically conductive test surface in an electrically conductive aqueous liquid, b. bringing an auxiliary electrode into electrical contact with said liquid, c. impressing a DC current source between said test surface and said electrode, the polarity of said source being such that said test surface has a predetermined polarity relative to said electrode, and d. sensing whether or not significant scale is precipitating out of said liquid and adhering to said test surface, said last-named step being performed by detecting any increase in the electrical contact resistance between said test surface and a contact element in engagement therewith.
Claim 36
Dependent Claim
30 words
The invention as claimed in claim 32, in which said step (d) is performed by causing said contact element to be a potential tap transmitting voltage to a voltmeter means.
Claim 37
Independent Claim
128 words
A method of monitoring a liquid-containing industrial system to determine the precipitation of adherent coatings from the liquid onto system surfaces exposed to said liquid, said method comprising: a. providing an electrically conductive test surface, b. exposing said test surface to substantially the same liquid present in the industrial system being monitored, c. causing the conditions present at said test surface to correspond substantially to the conditions present at at least one portion of the industrial system being monitored, and d. detecting, through use of a contact element associated with said test surface, an increase in the electrical contact resistance at said test surface, said increase being an indication that an adherent coating is precipitating from said liquid onto surfaces at said one portion of said industrial system.
Claim 38
Independent Claim
128 words
A method of monitoring a liquid-containing industrial system to determine the precipitation of adherent coatings from the liquid onto system surfaces exposed to said liquid, said method comprising: a. providing an electrically conductive test surface, b. exposing said test surface to substantially the same liquid present in the industrial system being monitored, c. causing the conditions present at said test surface to correspond substantially to the conditions present at at least one portion of the industrial system being monitored, and d. detecting, through use of a contact element associated with said test surface, an increase in the electrical contact resistance at said test surface, said increase being an indication that an adherent coating is precipitating from said liquid onto surfaces at said one portion of said industrial system.
Claim 39
Independent Claim
117 words
A method of detecting the deposition of adherent precipitate on a surface, which comprises: a. providing an electrically conductive test surface, b. exposing said test surface to a liquid which will, under at least one set of conditions, deposit an adherent precipitate onto said test surface. c. determining when the electrical contact resistance at said test surface increases due to deposition of adherent precipitate thereon, d. cleaning said test surface to substantially remove said precipitate therefrom, and e. again determining when the electrical contact resistance at said test surface increases due to deposition of adherent precipitate thereon, said determinations of electrical contact resistance at said test surface being effected by contact means associated with said test surface.
Claim 40
Independent Claim
117 words
A method of detecting the deposition of adherent precipitate on a surface, which comprises: a. providing an electrically conductive test surface, b. exposing said test surface to a liquid which will, under at least one set of conditions, deposit an adherent precipitate onto said test surface. c. determining when the electrical contact resistance at said test surface increases due to deposition of adherent precipitate thereon, d. cleaning said test surface to substantially remove said precipitate therefrom, and e. again determining when the electrical contact resistance at said test surface increases due to deposition of adherent precipitate thereon, said determinations of electrical contact resistance at said test surface being effected by contact means associated with said test surface.
Claim 41
Dependent Claim
53 words
The invention as claimed in claim 35, in which said method further comprises effecting said cleaning step as soon as precipitate is first determined to adhere to said test surface, and maintaining a substantial balance between cleaning and precipitate deposition, whereby to present deposition of major amounts of precipitate on said test surface.
Claim 42
Independent Claim
131 words
A method of determining the onset of formation of an adherent precipitate from a liquid onto a test surface immersed therein, which comprises: a. immersing a test surface in a liquid, said liquid being adapted, under at least one set of conditions, to precipitate an adherent coating onto a surface immersed therein, b. immersing an auxiliary contact surface in said liquid, at least one of said surfaces being round, c. causing relatively low-speed rolling conTact to occur between said immersed surfaces, and d. determining the electrical contact resistance at the region of rolling contact between said surfaces, whereby an increase in said electrical contact resistance will occur in response to separation of said surfaces caused by deposition onto at least one of said surfaces of a coating precipitated from said liquid.
Claim 43
Independent Claim
131 words
A method of determining the onset of formation of an adherent precipitate from a liquid onto a test surface immersed therein, which comprises: a. immersing a test surface in a liquid, said liquid being adapted, under at least one set of conditions, to precipitate an adherent coating onto a surface immersed therein, b. immersing an auxiliary contact surface in said liquid, at least one of said surfaces being round, c. causing relatively low-speed rolling conTact to occur between said immersed surfaces, and d. determining the electrical contact resistance at the region of rolling contact between said surfaces, whereby an increase in said electrical contact resistance will occur in response to separation of said surfaces caused by deposition onto at least one of said surfaces of a coating precipitated from said liquid.
Claim 44
Dependent Claim
45 words
The invention as claimed in claim 37, in which said liquid is an electrical conductor, and in which said method further comprises determining said contact resistance by passing current through said region of rolling contact, and then sensing the voltage drop through said contact region.
Claim 45
Dependent Claim
30 words
The invention as claimed in claim 37, in which said method further comprises periodically cleaning at least one of said surfaces by effecting relatively high-speed rolling contact between said surfaces.
Claim 46
Dependent Claim
31 words
The invention as claimed in claim 37, in which said method further comprises cleaning at least one of said surfaces by employing both rolling contact and sliding contact between said surfaces.
Claim 47
Independent Claim
141 words
A method of sensing the onset of formation of adherent scale of other precipitate coating on a test surface, which comprises: a. exposing a test surface to a liquid which will, under at least some conditions, precipitate an adherent coating thereon, b. providing an auxiliary contactor, c. effecting sequential engagement between said auxiliary contactor and different portions of said test surface, said engagement step, and the shape of said contactor, being such that the engaging of said contactor and said test surface does not cause penetration or removal of substantial deposited coating, or effect prevention of formation of such coating, d. periodically sensing the contact resistance between said contactor and test surface, and e. utilizing an increase in said sensed contact resistance as an indication that adherent coating material is precipitating out of said liquid and depositing on said test surface.
Claim 48
Independent Claim
141 words
A method of sensing the onset of formation of adherent scale of other precipitate coating on a test surface, which comprises: a. exposing a test surface to a liquid which will, under at least some conditions, precipitate an adherent coating thereon, b. providing an auxiliary contactor, c. effecting sequential engagement between said auxiliary contactor and different portions of said test surface, said engagement step, and the shape of said contactor, being such that the engaging of said contactor and said test surface does not cause penetration or removal of substantial deposited coating, or effect prevention of formation of such coating, d. periodically sensing the contact resistance between said contactor and test surface, and e. utilizing an increase in said sensed contact resistance as an indication that adherent coating material is precipitating out of said liquid and depositing on said test surface.
References Cited (Backward Citations)
US2374088A
Cited
US3748247A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |