US5280250A
Expired / Lapsed
US
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Method and apparatus for measuring ζ potential of a substance at high temperature
Assignee: SRI International Inc
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Filing: 1991-09-30
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Granted: 1994-01-18
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Expires: 2011-09-30
Abstract
Abstract The invention describes a novel device to measure ζ-potentials of substances at high temperatures. The device involves packing the substance to be measured into a "RULON" (polytetrafluoroethylene including a heat resistant filler, e.g., fiberglass, quartz, asbestos, ceramic fibers or mica) column and passing an electrolyte through the column. Measurements are taken across the column to measure streaming potential and the pressure drop, and a sensor in series with the column to measure the pH of the electrolyte. ζ-potentials are calculated from slopes of the plots of streaming potential (ΔE) vs. differential pressure (ΔP) using a computer controlled data acquisition system.
Inventors
- 👤 Palitha Jayaweera
- 👤 Samson Hettiarachchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:27
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/447; G01N27/44704; G01N27/44752
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
223 words
An apparatus for measuring the ζ-potential of a substance at high temperature comprising: a. a measurement loop defining a passageway formed to permit passage of an electrolyte at a high temperature and a high pressure therethrough; b. pump means capable of moving said electrolyte from a storage source through said passageway; c. a temperature control device operably coupled to said measurement loop in a manner capable of raising and lowering the temperature of said electrolyte in said passageway in response to monitoring the temperature of said electrolyte; d. a measuring column defining a chamber formed and dimensioned to receive said substance therein, said chamber in communicating relation with said passageway in a manner permitting fluid contact of said electrolyte with said substance from an entrance into said chamber to an exit from said chamber, said column further formed to provide electrical isolation of said substance from said measurement loop at said high temperature and pressure, and including electrodes positioned proximate said entrance and said exit of said chamber for measuring a streaming potential across said substance after contact with said electrolyte; and e. a pressure measuring device operably coupled to said passageway and positioned in parallel with said column along said passageway for measurement of a differential pressure across a portion of said passageway before and after said electrolyte has contacted said substance.
Claim 2
Independent Claim
223 words
An apparatus for measuring the ζ-potential of a substance at high temperature comprising: a. a measurement loop defining a passageway formed to permit passage of an electrolyte at a high temperature and a high pressure therethrough; b. pump means capable of moving said electrolyte from a storage source through said passageway; c. a temperature control device operably coupled to said measurement loop in a manner capable of raising and lowering the temperature of said electrolyte in said passageway in response to monitoring the temperature of said electrolyte; d. a measuring column defining a chamber formed and dimensioned to receive said substance therein, said chamber in communicating relation with said passageway in a manner permitting fluid contact of said electrolyte with said substance from an entrance into said chamber to an exit from said chamber, said column further formed to provide electrical isolation of said substance from said measurement loop at said high temperature and pressure, and including electrodes positioned proximate said entrance and said exit of said chamber for measuring a streaming potential across said substance after contact with said electrolyte; and e. a pressure measuring device operably coupled to said passageway and positioned in parallel with said column along said passageway for measurement of a differential pressure across a portion of said passageway before and after said electrolyte has contacted said substance.
Claim 3
Dependent Claim
16 words
An apparatus of claim 1, wherein said pump means is a high-pressure liquid chromatography (HPLC) pump.
Claim 4
Dependent Claim
14 words
An apparatus of claim 1, wherein said measurement loop includes tubing providing said passageway.
Claim 5
Dependent Claim
12 words
An apparatus of claim 3, wherein said tubing comprises stainless steel tubing.
Claim 6
Dependent Claim
25 words
An apparatus of claim 1, wherein said electrolyte is selected from the group consisting of KCl, KNO 3 , NaNO3, NaCl or any inert electrolyte.
Claim 7
Dependent Claim
31 words
An apparatus of claim 1, further including a pH measuring device positioned across a portion of said passageway and capable of measuring the pH of said electrolyte at said high temperature.
Claim 8
Dependent Claim
20 words
An apparatus of claim 6, wherein said pH measuring device is positioned along said passageway downstream from said measuring column.
Claim 9
Dependent Claim
24 words
An apparatus of claim 1, wherein said high temperature of said electrolyte is in the range from about 100° C. to about 300° C.
Claim 10
Dependent Claim
24 words
An apparatus of claim 1, wherein said high pressure of said electrolyte is in the range from about 10 psi to about 1200 psi.
Claim 11
Dependent Claim
38 words
An apparatus of claim 3, wherein said temperature control device comprises heating means in heat communication with a portion of said passageway, cooling means in cooling communication with another portion of said passageway, and a temperature monitoring device.
Claim 12
Dependent Claim
21 words
An apparatus of claim 1, wherein said pressure measuring device comprises a different pressure transducer capable of measuring said differential pressure.
Claim 13
Dependent Claim
75 words
An apparatus of claim 10, wherein said heating means comprises heating tape in conductive contact with said tubing at a position upstream from said column, said cooling means comprises a cooling jacket in conductive contact with said tubing at a positioned downstream from said column, and said temperature monitoring device is provided by a first thermocontroller positioned proximate one end of said column, and a second thermocontroller positioned proximate an opposite end of said column.
Claim 14
Dependent Claim
14 words
An apparatus of claim 12, wherein said cooling jacket is a cooling water jacket.
Claim 15
Dependent Claim
35 words
An apparatus of claim 6, wherein said pH measuring device comprises a yttria-stabilized sirconia pH electrode, and an external pressure balanced reference electrode capable of providing a reference potential for pH measurement of said electrolyte.
Claim 16
Dependent Claim
41 words
An apparatus of claim 1, wherein said measuring column comprises an electrical insulating ring defining said chamber, and formed and dimensioned to be positioned inside said passageway in a manner providing said electrical insulation of said substance from said measurement loop.
Claim 17
Dependent Claim
10 words
An apparatus of claim 15, wherein said ring comprises "RULON".
Claim 18
Dependent Claim
52 words
An apparatus of claim 15, wherein said column further includes a first Pt screen positioned proximate said entrance into said column chamber, and a second Pt screen positioned proximate said exit from said column chamber, said first and said second Pt screens cooperating to tightly support said substance therebetween in said chamber.
Claim 19
Dependent Claim
17 words
An apparatus of claim 17, wherein said Pt screens are electrically conductive and serve as said electrodes.
Claim 20
Dependent Claim
55 words
An apparatus of claim 18, wherein said column further includes a first screen holder ring urging said first Pt screen against said column, and a second screen holder ring urging said second Pt screen against said column, aid screen holder rings each being formed to electrically insulate said Pt screens, respectively, from said measurement loop.
Claim 21
Dependent Claim
37 words
An apparatus of claim 18, wherein said column further includes a first "TEFLON" filter positioned between said first screen holder and said column, and a second "TEFLON" filter positioned between said second screen holder and said column.
Claim 22
Dependent Claim
22 words
An apparatus of claim 18, wherein said column further includes "RULON" ferrules electrically isolating contacts to each electrode from said measurement loop.
Claim 23
Dependent Claim
60 words
An apparatus of claim 1, further including computation means operably coupled to said measuring column, for input of said streaming potential thereto, and operably coupled to said pressure measuring device, for input of said differential pressure thereto, said computation means calculating the ζ-potential of said substance through use of said streaming potential and said differential pressure in a predetermined equation.
Claim 24
Dependent Claim
11 words
An apparatus of claim 1, wherein said column is thermally insulated.
Claim 25
Independent Claim
262 words
A method for measuring the ζ-potential of a substance at a high temperature and pressure in a ζ-potential measuring apparatus, said apparatus comprising a measurement loop defining a passageway formed to permit passage of an electrolyte at a high temperature and a high pressure therethrough, pump means capable of moving said electrolyte from a storage source through said passageway, and a temperature control device operably coupled to said measurement loop in a manner capable of raising and lowering the temperature of said electrolyte in said passageway in response to monitoring the temperature of said electrolyte, said method comprising the steps of: positioning a measuring column, defining a chamber formed and dimensioned to receive said substance therein, along and in communicating relation with said passageway in a manner permitting fluid contact of said electrolyte with said substance therein from an entrance into said chamber to an exit from said chamber; electrically isolating said substance from said measurement loop at said high temperature and pressure through placement of said substance in said chamber; measuring a streaming potential across said substance, after contact of said substance with said electrolyte, by positioning electrodes proximate said entrance and said exit of said chamber; measuring a differential pressure across a portion of said passageway at positions before and after said electrolyte has contacted said substance through a pressure measuring device operably coupled to said passageway and positioned in parallel with said column along said passageway; and calculating said ζ-potential measurement of said substance by factoring said differential pressure measurement and said steaming potential measurement into a predetermined equation.
Claim 26
Independent Claim
262 words
A method for measuring the ζ-potential of a substance at a high temperature and pressure in a ζ-potential measuring apparatus, said apparatus comprising a measurement loop defining a passageway formed to permit passage of an electrolyte at a high temperature and a high pressure therethrough, pump means capable of moving said electrolyte from a storage source through said passageway, and a temperature control device operably coupled to said measurement loop in a manner capable of raising and lowering the temperature of said electrolyte in said passageway in response to monitoring the temperature of said electrolyte, said method comprising the steps of: positioning a measuring column, defining a chamber formed and dimensioned to receive said substance therein, along and in communicating relation with said passageway in a manner permitting fluid contact of said electrolyte with said substance therein from an entrance into said chamber to an exit from said chamber; electrically isolating said substance from said measurement loop at said high temperature and pressure through placement of said substance in said chamber; measuring a streaming potential across said substance, after contact of said substance with said electrolyte, by positioning electrodes proximate said entrance and said exit of said chamber; measuring a differential pressure across a portion of said passageway at positions before and after said electrolyte has contacted said substance through a pressure measuring device operably coupled to said passageway and positioned in parallel with said column along said passageway; and calculating said ζ-potential measurement of said substance by factoring said differential pressure measurement and said steaming potential measurement into a predetermined equation.
Claim 27
Dependent Claim
23 words
A method of claim 24, wherein said electrolyte is selected from the group consisting of Kcl, KNO3, NaCl, NaNO3 or any inert electrolyte.
Claim 28
Dependent Claim
60 words
A method of claim 24, wherein said predetermined equation is provided by (ΔE)/(ΔP)=((E 0 Dr 2 R)/(4η1))ζ, wherein ΔE=the streaming potential, ΔP=the differential pressure, E 0 =the permittivity of free space, D=the dielectric constant of the median, r=the radius of the column, R=the resistance of the substance packed column, η=the viscosity of the electrolyte, and 1=the length of the column.
Claim 29
Dependent Claim
14 words
A method of claim 24, wherein said measurement loop includes tubing providing said passageway.
Claim 30
Dependent Claim
41 words
A method of claim 24 further including the step of: measuring the pH of the electrolyte across a portion of said passageway through a pH measuring device capable of measuring the pH at said high temperature and positioned along said passageway.
Claim 31
Dependent Claim
40 words
A method of claim 24, wherein said column comprises an electrical insulating ring defining said chamber, and formed and dimensioned to be positioned inside said passageway in a manner providing said electrical insulation of said substance from said measurement loop.
Claim 32
Dependent Claim
53 words
A method of claim 24, wherein said measuring column further includes a first Pt screen positioned proximate said entrance into said column chamber, and a second Pt screen positioned proximate said exit from said column chamber, said first and said second Pt screens cooperating to tightly support said substance therebetween in said chamber.
Claim 33
Dependent Claim
22 words
A method of claim 30, wherein said Pt screens are comprised of an inert electrically conductive material and serve as said electrodes.
Claim 34
Dependent Claim
55 words
A method of claim 31, wherein said column further includes a first screen holder ring urging said first Pt screen against said column, and a second screen holder ring urging said second Pt screen against said column, said screen holder rings each being formed to electrically insulate said Pt screens, respectively, from said measurement loop.
Claim 35
Dependent Claim
20 words
A method of claim 24, wherein said pressure is in the range from about 10 psi to about 1200 psi.
Claim 36
Dependent Claim
20 words
A method of claim 24, wherein said temperature is in the range from about 100° C. to about 300° C.
Claim 37
Dependent Claim
19 words
A method of claim 24, wherein said predefined temperature is adjustable by means of a temperature control device 4.
Claim 38
Dependent Claim
15 words
A method of claim 24, wherein said pressure measuring device comprises a differential pressure transducer.
Claim 39
Dependent Claim
17 words
A method of claim 24, wherein said pH measuring device comprises a yttria-stabilized zirconia (YSZ) pH electrode.
Claim 40
Dependent Claim
47 words
A method of claim 24, wherein said pH measuring device comprises a yttria-stabilized zirconia (YSZ) pH electrode, and an external pressure balanced reference electrode (EPBRE) capable of providing a reference potential for measuring the pH of said electrolyte when the temperature of said electrolyte at high temperature.
Claim 41
Dependent Claim
42 words
A method of claim 24, wherein said calculating step is accomplished by computation means operably coupled to said measuring column, for input of said streaming potential thereto, and operably coupled to said pressure measuring device, for input of said differential pressure thereto.
Claim 42
Dependent Claim
37 words
A method of claim 32, wherein said column further includes a first "TEFLON" filter positioned between said first screen holder and said column, and a second "TEFLON" filter positioned between said second screen holder and said column.
References Cited (Backward Citations)
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