CA2030965C - Ionizable substance detector - Google Patents
Ionizable substance detectorInfo
- Publication number
- CA2030965C CA2030965C CA002030965A CA2030965A CA2030965C CA 2030965 C CA2030965 C CA 2030965C CA 002030965 A CA002030965 A CA 002030965A CA 2030965 A CA2030965 A CA 2030965A CA 2030965 C CA2030965 C CA 2030965C
- Authority
- CA
- Canada
- Prior art keywords
- stream
- substance
- power source
- ions
- introducing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000000126 substance Substances 0.000 title claims abstract description 65
- 150000002500 ions Chemical class 0.000 claims abstract description 43
- 239000003574 free electron Substances 0.000 claims abstract description 27
- 239000003014 ion exchange membrane Substances 0.000 claims abstract description 18
- 239000001257 hydrogen Substances 0.000 claims description 23
- 229910052739 hydrogen Inorganic materials 0.000 claims description 23
- 239000012528 membrane Substances 0.000 claims description 20
- 230000003197 catalytic effect Effects 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 15
- 239000003054 catalyst Substances 0.000 claims description 13
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 8
- 239000001301 oxygen Substances 0.000 claims description 8
- 229910052760 oxygen Inorganic materials 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims description 3
- 229910052741 iridium Inorganic materials 0.000 claims description 3
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052763 palladium Inorganic materials 0.000 claims description 3
- 229910052703 rhodium Inorganic materials 0.000 claims description 3
- 239000010948 rhodium Substances 0.000 claims description 3
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052707 ruthenium Inorganic materials 0.000 claims description 3
- 239000011734 sodium Substances 0.000 claims description 3
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 claims description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052794 bromium Inorganic materials 0.000 claims description 2
- 239000000460 chlorine Substances 0.000 claims description 2
- 229910052801 chlorine Inorganic materials 0.000 claims description 2
- 238000004891 communication Methods 0.000 claims description 2
- 239000011737 fluorine Substances 0.000 claims description 2
- 229910052731 fluorine Inorganic materials 0.000 claims description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 6
- 238000012544 monitoring process Methods 0.000 abstract description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 150000002431 hydrogen Chemical class 0.000 description 4
- 229920000557 Nafion® Polymers 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000376 reactant Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000004809 Teflon Substances 0.000 description 2
- 229920006362 Teflon® Polymers 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- 241000518994 Conta Species 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 230000002925 chemical effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000003411 electrode reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- -1 hydL~en Substances 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000037427 ion transport Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- 239000006163 transport media Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/404—Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors
- G01N27/4045—Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors for gases other than oxygen
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
- G01N27/42—Measuring deposition or liberation of materials from an electrolyte; Coulometry, i.e. measuring coulomb-equivalent of material in an electrolyte
- G01N27/423—Coulometry
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04276—Arrangements for managing the electrolyte stream, e.g. heat exchange
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
The amount of ionizable substance within a stream can be continuously monitored through the use of an ionizable substance detector. The substance is ionized at an electrode producing ions and free electrons. The ions are transported across an ion exchange membrane, while the free electrons flow through a power source. The current, produced by the electrons, is proportional to the amount of substance in the stream. Continuous monitoring can be useful in early detection of problems, or system fluctuations.
Description
" 2030~6~
Description Ionizable Substance Detector Technical Field T~is invention relates to detecting ionizable subst~nses, and especi~lly to detectlng ion forming substances.
RAr~J ~ d Art Detecting ion~ z~hle substances, such as hydL~en, sodium, and chlorinec among others, within a stream can be important for various re~RonC. For example, within a fuel cell, electrolyzer, or other process, the amount of ioniz~hle substance in a stream can be critical ~ep~nd~ng on the stream's use. A water stream for instance, inte- s~ for illL~oduction into an o~yy~n stream, must be essentially free of hydLo~en in order to ~Lcvel.L an explosion. In another instance, it may be necessAry to monitor an exhaust stream to comply with environmental protection requirements.
U.S. Pat. No. 4,227,984 discloses a t chnique for sensing protons utilizing reference, sensing, and counter ele~L~odes in combination with a membrane.
All of the elecLLodes are located on one side of the membrane and positioned such that an ionic resistance path beL~een the sensing and reference ele~Llode is greater than 60 ohms. The arrangement places the reference ele~LLode outside the ~uLLenL flux lines beL~-~&n the sensing and counter electrodes. Similar te~h~ques are disclosed in U.S~ Pat. Nos. 4,123,700 and 4,171,253. Problems with these systems include a relatively slow LeD~.,se time (100 to 200 cecon~
203096~
and a potential interference caused by permeation to the sensing electrode of the reactant products generated at the counter electrode.
U.S. Pat. No. 4,820,386 which discloses an S i _~ved ~ethod from that mentioned above resolves these problems. Instead of locating all of the electrodes on one side of the membrane, the sensing and counter electrodes are located on the same side of the membrane with the reference electrode located on the opposite side of the membrane directly across from the sensing electrode. This arrang- -nt allows for a faster, but still not sufficient, reSpQn~e time (approximately 12.0 seconAc)~ with greater immunity to interference from counter electrode reaction products.
Oxidation occurs at the sensing electrode and protons are transferred across the membrane by proton ~Y~h~nge between the sensing and counter electrode. The current generated is pLopG~Lional to the partial pressure of the reactant gas in the stream.
Another method for sensing hydrogen (or carbon mon~Yi~e) is disclosed in U.S. Pat. No. 4,718,991. In this system, a pair of electrodes connected to a proton conductor are short-circuited to cause the protons to travel through the conductor. The potential difference prodtlce~ in the interior of the con~~lctor is obtaine~ as the o~L~L of the s~ncor.
The c~ nLration of the hydrogen (or carbon monoYi~e) is proportional to this ~u~puL. At the reference electrode, the hydrogen which has been ionized at the ionization electrode, is reacted with oxygen to form water. The disadvantages of this process include changing the composition of the strea~t (disturbing the -' 2030965 stream), and the requirement of oxygen to operate ~he system~
Other techniques, such as removing, testing, and discarding samples from the stream or solution, have also been utilized for substance detection. However, in certain applications, such as extraterrestrial applicationa, this technique is not only impractical, it is inefficient and cumbersome.
The above mentioned devices havQ a potential for interference from the reaction products and operate relatively slow. What is neede~ in this art is a method for continually detecting the conc~r~ration of an io~izAhle substance within a stream in a relatively concise ~nner~ without significantly disrupting the stream flow.
Disclosure of Invention The present invention discloses a detector useful for continuously monitoring an ionizable substance in a fluid stream. The detector comprises a catalytic cathode and anode electrode, an ion ~y~h~n~e membrane, a power source, a current measuring device, and a means fox inl,ol~lcin~ and removing the ionizable substance.
The method disclosed comprises applying a potential across the ion ~Y~h~n~e membrane via a power source. The ionizable substance, ionized at the anode, pro~uce~ ions and free electrons. The free ele~Lons pass from the anode to the cathode through the power source. The amount of free electrons which pass through the power source, measured with a current measuring device, is proportional to the amount of the ionizable substance within the stream. The ions are then reformed into molecules at the cathode and removed from the detector.
In accordance with a particular embodiment of the invention there is provided a method of detecting ionizable substance in a stream, which comprises:
a. using a detector, said detector including a means for introducing and a means for removing said stream containing an ionizable substance, a current measuring device, a power source, a catalytic cathode electrode, a catalytic anode electrode, and an ion exchange membrane disposed therebetween;
b. introducing said stream containing said ionizable substance to the anode electrode via said means for introducing said streami c. applying and maintaining a potential across said ion exchange membrane from said power source;
d. ionizing said substance at said anode electrode, wherein ions and free electrons are produced;
e. transferring said ions across said ion exchange membrane to said cathode electrode;
f. passing said free e:Lectrons through said power source to said cathode electrode;
g. using said current measuring device to determine the current produced by the free electrons which pass through said power source, wherein said . :. ,, - 4a -current measuring device is connected to said power source;
h. recombining said ions and said free electrons at the cathode electrode to produce the molecular form of said ionizable substance; and i. reintroducing the molecular substance to said stream in said means for removing said stream, wherein said stream flows first through said means for introducing said stream and then through said means for removing said stream;
whereby the current flow of the electrons across the power source is the same as the current flow of the ions across the ion exchange membrane, and wherein measurement of said current provides a measurement of the ionizable substance flow.
From a different aspect, ar.d in accordance with a particular embodiment of the invention there is provided an apparatus for detecting an ionizable substance in a stream comprising:
a. a means for introducing said stream containing said ionizable substance to the apparatus, said means for introducing constructed and arranged for allowing said stream to exit to a flow channel;
b. a catalytic anode electrode for ionizing said substance, producing ions and free electrons;
c. a catalytic cathode electrode for recombining said ions with said free electrons to return said substance to its molecular form and to reintroduce - 4b -the reformed substance back into said stream;
d. an ion exchange membrane for transporting said ions from said anode electrode to said cathode electrode, wherein said ion exchange membrane is disposed between and in intimate contact with said anode electrode and said cathode electrode;
e. a power source for maintaining a potential across said ion exchange membrane and through which said free electrons pass, wherein said potential influences the flow of said ions from the anode electrode to the cathode electrode;
f. a current measuring device connected to said power source, wherein said current measuring device monitors the amount of electrons which pass through said power source; and g. a means for removing said stream containing said reintroduced substance from said apparatus, wherein said means for removing is constructed and arranged for accepting said stream from the flow channel and said stream passes through said means for introducing, enters the flow channel, passes through the flow channel, and enters said means for removing such that said means for introducing and said means for removing are in flow communication;
- 4c -whereby the flow of the free electrons through the power source is proportional to the amount of ionizable substance within the stream.
The foregoing and other features and advantages of the present invention will become more apparent from the following description and accompanying drawings.
Brief Description of Drawings The figure is a schematic of one embodiment of the present invention.
Best Mode for Carrying Out the Invention The present invention can be utilized to detect any ionic substance, such as hydrogen, sodium, fluorine, chlorine, oxygen, bromine, among others, which, when ionized, produces free electrons. The Figure, a schematic of one embodiment of the present invention, reveals the essential aspects of the invention. The detector, possessing all of the conventional components of a fuel cell/electrolyzer, is comprised of an anode electrode (13), with a catalytic layer capable of ionizing the substance; a cathode electrode (15), with a catalytic layex, capable of recombining the ions and free electrons; and an ion exchange membrane (5) which is used as an ion transport medium is disposed therebetween. A power source (7) is used to maintain a potential across the ion exchange membrane (5) to influence the flow of ions from the anode (13) to the cathode (15). The free electrons pass from the anode to the cathode through a current measuring device (17) which measures the amount of current produced by the flow of free electrons from the anode (13) to the cathode (15).
In "' 203096~
intimate contact with the anode i8 a means ~or introducing the substance (a feed chamber) (3), and, in intimate contact with the cathode i8 a means for removing the sub~tance from the detector (a reflow chamber) (9).
I~ practicing the invention, the fluid stream (l) (such as a water stream, or a gas/gas stream) conta;n1n~ the ionizable substanc~ enters the feed chr- 'cr (3). The substance is catalytically ionized at the anode electrode (13) producing ions and free electrons. A DC potential, maintaine~ across the ion ~Y~-hAnge membrane by the power source (7), influences the flow of ions across the ion ~Y~hAng~ membrane (5) to the cathode (15). The electrons simul~Aneo--c1y pass through the current s-C~ring device (17) which monitors the current produce~. At the cathode (15), the ions and electrons recombine to produce the molecular form of the substance. The molecular substance reenters the stream (l) which has simultAneollc1y been inL~o1l~ce~ to the reflow ehr '-r (9). The stream (l) exits the detector at point (ll).
The power source, which maintains the DC
potential across the ion ~Y~hAngc membrane, serves two ~L~oses: to con~uct the free electrons prod-~ce~ at the anode ele~LLode to the cathode electrode, and to supply the voltage necessAry to influence the flow of ions from the anode to the cathode. Although any ~uLLenL measuring device which can accurately measure ~urLel.L can be utilized, an ampere meter is preferred.
The ~uL-L~rL --cllred is ~L~G~Lional to the amount of ioniz~hle substance present in the stream.
For example, for the detection of h~dLo~en in a water stream, each ampere of current flow removes 7.52 203096~
ccfmin. of hydrogen from th~ stream. Therefore, the current which passes through the power source per unit time, is proportional to the ~ -u..~ of hydrogen detected. Knowing that 1 amp-min. is equivalent to pumping 7.52 cc of molecular hydrogen at any fixed voltage up to 1.23 volts (for this particular example), the amount of hyd~oyen within the str~am can be determined. A voltage sufficient to transport the i ions across the membrane without interfering with the current reading can be used.
In the particular application described above, a voltage of about 0.50 to about 1.23 volts is preferred, with 0.50 volts especially preferred.
Voltages greater than 1.23 volts can cause water electrolysis which, in turn, effects the current re~i ng and the accuracy of the detector.
Utilization of this invention with different substances may require a different type o~ catalyst and ion ~Y~h~~ge membrane; both of which may be conventional. The type of catalyst will be ~epDn~ent on the substance to be ionized, and the operating conditions. The ion ~Y~h~nge - 'Lane will be dependent upon the size of the ionized substance, if it can be transferred across the membrane under a reasonable operating potential. Other factors which will effect the determination of the type of membrane to be utilized include the operating temperature, the type of ion to be transferred (cation or anion), and the chemical effects of the substance on the membrane and vice versa. All of these parameters can readily be determined by one skilled in this art.
In detecting hydrogen, for example, the catalyst must be capable of ionizing the hydrogen: and may be 2030~6~
any one of a number of conventional catalysts utilized in electrolysis cells to ~ifi~C~ociate hydrogen. The preferred catalyst is based on a metal from the platinum family, such as ruthenium, rhodium, palladium, iridium, and platinum, with platinum black bonded with Teflon-, produced by Du Pont de Nemours, E. I. & Company, (metal lo~n~ of 4.0 mg/cm2) especially preferred; altho~l~h differant catalysts can be utilized. Variou~ ion ~Y~h~nge membranes can also be utilized, with Nafion- pro~uce~ by Du Pont de Nemours, Inc., preferred. The operating temperature for Nafion should not ~Ycee~ approximately 250~F.
Therefore, any device utilizing this particular membrane preferably operated above the freezing point lS of the stream, and below approximately 250~F.
As with the temperature, tha pressure and flow ratesof the stream can vary greatly. In order to detect the substance at various temperatures, pressures, and flow rates, the uu~uL readings ~ust be calibrated for the particular substance to be detected, and the system operating conditions.
To calibrate the system, the pressure, temperature, and flow rate are held constant for the desired conditions; while the stream cont~inin~ the substance is p~se~ through the detector. Once the stream exits the detector, it is place within a conventional device for measuring the substance.
Hydrogen, for example, can be placed within low pressure device which liberates the hydrogen, allowing the amount of hydrogen in the stream to ba measured.
The amount of substance determined by the detector is compared with the amount of substance actually in the stream. If, for instance, 72.0 percent of the ~030~6~
substance was detected with the detector, the detector rea~n~ must be ad~usted. The ad~u#tment consists of dividing the amount of substance detected by 0.72 to determine the actual amount of substance within the stream.
This process, which permit~ continuo~c monitoring of the subctance conc~ntration within a fluid stream, creates detection devices for discovering problems, or system fluctuations early. Also, since the substance is reintro~-~ce~ to the stream, the problem of disposing the test sample never arises, nor doe~ the problem of ac lating test samples within the system; the stream is essentially undisturbed by the p~ocess. Furthermore, if the stream is h- -,eneous, this determination is highly accurate; without invasive sampling.
This invention is particularly useful for detecting hydrogen in a water stream of a fuel cell/electroyler system where it is nec~ssAry to have a closed system and/or where the hydrogen must not PYcee~ a given maximum. For instance, where the water stream is int~nde~ for astronaut consumption, or where the water stream will be in~lol~ce~ to an oxygen stream, it can be important or even critical to keep the.~l~dLu~en content of the water to a mini~um.
Continou~ monitoring of the hyd-o~en concentration within the water stream will allow early detection of potential disasterous problems: enabling them to be avoided.
Example 1 The following pLoced~re can be utilized to detect hydrogen wlthin a water/hydrogen stream for a life support system which pro~uce~ approximately 9.08 pounds of oxygen per day. (refer to the Figure).
1. A water/hydrogen stream i9 inLLo~ ce~ to the feed chamber (3) of the detector at 22.0 cc/min., 120~F, and 160 psia.
Description Ionizable Substance Detector Technical Field T~is invention relates to detecting ionizable subst~nses, and especi~lly to detectlng ion forming substances.
RAr~J ~ d Art Detecting ion~ z~hle substances, such as hydL~en, sodium, and chlorinec among others, within a stream can be important for various re~RonC. For example, within a fuel cell, electrolyzer, or other process, the amount of ioniz~hle substance in a stream can be critical ~ep~nd~ng on the stream's use. A water stream for instance, inte- s~ for illL~oduction into an o~yy~n stream, must be essentially free of hydLo~en in order to ~Lcvel.L an explosion. In another instance, it may be necessAry to monitor an exhaust stream to comply with environmental protection requirements.
U.S. Pat. No. 4,227,984 discloses a t chnique for sensing protons utilizing reference, sensing, and counter ele~L~odes in combination with a membrane.
All of the elecLLodes are located on one side of the membrane and positioned such that an ionic resistance path beL~een the sensing and reference ele~Llode is greater than 60 ohms. The arrangement places the reference ele~LLode outside the ~uLLenL flux lines beL~-~&n the sensing and counter electrodes. Similar te~h~ques are disclosed in U.S~ Pat. Nos. 4,123,700 and 4,171,253. Problems with these systems include a relatively slow LeD~.,se time (100 to 200 cecon~
203096~
and a potential interference caused by permeation to the sensing electrode of the reactant products generated at the counter electrode.
U.S. Pat. No. 4,820,386 which discloses an S i _~ved ~ethod from that mentioned above resolves these problems. Instead of locating all of the electrodes on one side of the membrane, the sensing and counter electrodes are located on the same side of the membrane with the reference electrode located on the opposite side of the membrane directly across from the sensing electrode. This arrang- -nt allows for a faster, but still not sufficient, reSpQn~e time (approximately 12.0 seconAc)~ with greater immunity to interference from counter electrode reaction products.
Oxidation occurs at the sensing electrode and protons are transferred across the membrane by proton ~Y~h~nge between the sensing and counter electrode. The current generated is pLopG~Lional to the partial pressure of the reactant gas in the stream.
Another method for sensing hydrogen (or carbon mon~Yi~e) is disclosed in U.S. Pat. No. 4,718,991. In this system, a pair of electrodes connected to a proton conductor are short-circuited to cause the protons to travel through the conductor. The potential difference prodtlce~ in the interior of the con~~lctor is obtaine~ as the o~L~L of the s~ncor.
The c~ nLration of the hydrogen (or carbon monoYi~e) is proportional to this ~u~puL. At the reference electrode, the hydrogen which has been ionized at the ionization electrode, is reacted with oxygen to form water. The disadvantages of this process include changing the composition of the strea~t (disturbing the -' 2030965 stream), and the requirement of oxygen to operate ~he system~
Other techniques, such as removing, testing, and discarding samples from the stream or solution, have also been utilized for substance detection. However, in certain applications, such as extraterrestrial applicationa, this technique is not only impractical, it is inefficient and cumbersome.
The above mentioned devices havQ a potential for interference from the reaction products and operate relatively slow. What is neede~ in this art is a method for continually detecting the conc~r~ration of an io~izAhle substance within a stream in a relatively concise ~nner~ without significantly disrupting the stream flow.
Disclosure of Invention The present invention discloses a detector useful for continuously monitoring an ionizable substance in a fluid stream. The detector comprises a catalytic cathode and anode electrode, an ion ~y~h~n~e membrane, a power source, a current measuring device, and a means fox inl,ol~lcin~ and removing the ionizable substance.
The method disclosed comprises applying a potential across the ion ~Y~h~n~e membrane via a power source. The ionizable substance, ionized at the anode, pro~uce~ ions and free electrons. The free ele~Lons pass from the anode to the cathode through the power source. The amount of free electrons which pass through the power source, measured with a current measuring device, is proportional to the amount of the ionizable substance within the stream. The ions are then reformed into molecules at the cathode and removed from the detector.
In accordance with a particular embodiment of the invention there is provided a method of detecting ionizable substance in a stream, which comprises:
a. using a detector, said detector including a means for introducing and a means for removing said stream containing an ionizable substance, a current measuring device, a power source, a catalytic cathode electrode, a catalytic anode electrode, and an ion exchange membrane disposed therebetween;
b. introducing said stream containing said ionizable substance to the anode electrode via said means for introducing said streami c. applying and maintaining a potential across said ion exchange membrane from said power source;
d. ionizing said substance at said anode electrode, wherein ions and free electrons are produced;
e. transferring said ions across said ion exchange membrane to said cathode electrode;
f. passing said free e:Lectrons through said power source to said cathode electrode;
g. using said current measuring device to determine the current produced by the free electrons which pass through said power source, wherein said . :. ,, - 4a -current measuring device is connected to said power source;
h. recombining said ions and said free electrons at the cathode electrode to produce the molecular form of said ionizable substance; and i. reintroducing the molecular substance to said stream in said means for removing said stream, wherein said stream flows first through said means for introducing said stream and then through said means for removing said stream;
whereby the current flow of the electrons across the power source is the same as the current flow of the ions across the ion exchange membrane, and wherein measurement of said current provides a measurement of the ionizable substance flow.
From a different aspect, ar.d in accordance with a particular embodiment of the invention there is provided an apparatus for detecting an ionizable substance in a stream comprising:
a. a means for introducing said stream containing said ionizable substance to the apparatus, said means for introducing constructed and arranged for allowing said stream to exit to a flow channel;
b. a catalytic anode electrode for ionizing said substance, producing ions and free electrons;
c. a catalytic cathode electrode for recombining said ions with said free electrons to return said substance to its molecular form and to reintroduce - 4b -the reformed substance back into said stream;
d. an ion exchange membrane for transporting said ions from said anode electrode to said cathode electrode, wherein said ion exchange membrane is disposed between and in intimate contact with said anode electrode and said cathode electrode;
e. a power source for maintaining a potential across said ion exchange membrane and through which said free electrons pass, wherein said potential influences the flow of said ions from the anode electrode to the cathode electrode;
f. a current measuring device connected to said power source, wherein said current measuring device monitors the amount of electrons which pass through said power source; and g. a means for removing said stream containing said reintroduced substance from said apparatus, wherein said means for removing is constructed and arranged for accepting said stream from the flow channel and said stream passes through said means for introducing, enters the flow channel, passes through the flow channel, and enters said means for removing such that said means for introducing and said means for removing are in flow communication;
- 4c -whereby the flow of the free electrons through the power source is proportional to the amount of ionizable substance within the stream.
The foregoing and other features and advantages of the present invention will become more apparent from the following description and accompanying drawings.
Brief Description of Drawings The figure is a schematic of one embodiment of the present invention.
Best Mode for Carrying Out the Invention The present invention can be utilized to detect any ionic substance, such as hydrogen, sodium, fluorine, chlorine, oxygen, bromine, among others, which, when ionized, produces free electrons. The Figure, a schematic of one embodiment of the present invention, reveals the essential aspects of the invention. The detector, possessing all of the conventional components of a fuel cell/electrolyzer, is comprised of an anode electrode (13), with a catalytic layer capable of ionizing the substance; a cathode electrode (15), with a catalytic layex, capable of recombining the ions and free electrons; and an ion exchange membrane (5) which is used as an ion transport medium is disposed therebetween. A power source (7) is used to maintain a potential across the ion exchange membrane (5) to influence the flow of ions from the anode (13) to the cathode (15). The free electrons pass from the anode to the cathode through a current measuring device (17) which measures the amount of current produced by the flow of free electrons from the anode (13) to the cathode (15).
In "' 203096~
intimate contact with the anode i8 a means ~or introducing the substance (a feed chamber) (3), and, in intimate contact with the cathode i8 a means for removing the sub~tance from the detector (a reflow chamber) (9).
I~ practicing the invention, the fluid stream (l) (such as a water stream, or a gas/gas stream) conta;n1n~ the ionizable substanc~ enters the feed chr- 'cr (3). The substance is catalytically ionized at the anode electrode (13) producing ions and free electrons. A DC potential, maintaine~ across the ion ~Y~-hAnge membrane by the power source (7), influences the flow of ions across the ion ~Y~hAng~ membrane (5) to the cathode (15). The electrons simul~Aneo--c1y pass through the current s-C~ring device (17) which monitors the current produce~. At the cathode (15), the ions and electrons recombine to produce the molecular form of the substance. The molecular substance reenters the stream (l) which has simultAneollc1y been inL~o1l~ce~ to the reflow ehr '-r (9). The stream (l) exits the detector at point (ll).
The power source, which maintains the DC
potential across the ion ~Y~hAngc membrane, serves two ~L~oses: to con~uct the free electrons prod-~ce~ at the anode ele~LLode to the cathode electrode, and to supply the voltage necessAry to influence the flow of ions from the anode to the cathode. Although any ~uLLenL measuring device which can accurately measure ~urLel.L can be utilized, an ampere meter is preferred.
The ~uL-L~rL --cllred is ~L~G~Lional to the amount of ioniz~hle substance present in the stream.
For example, for the detection of h~dLo~en in a water stream, each ampere of current flow removes 7.52 203096~
ccfmin. of hydrogen from th~ stream. Therefore, the current which passes through the power source per unit time, is proportional to the ~ -u..~ of hydrogen detected. Knowing that 1 amp-min. is equivalent to pumping 7.52 cc of molecular hydrogen at any fixed voltage up to 1.23 volts (for this particular example), the amount of hyd~oyen within the str~am can be determined. A voltage sufficient to transport the i ions across the membrane without interfering with the current reading can be used.
In the particular application described above, a voltage of about 0.50 to about 1.23 volts is preferred, with 0.50 volts especially preferred.
Voltages greater than 1.23 volts can cause water electrolysis which, in turn, effects the current re~i ng and the accuracy of the detector.
Utilization of this invention with different substances may require a different type o~ catalyst and ion ~Y~h~~ge membrane; both of which may be conventional. The type of catalyst will be ~epDn~ent on the substance to be ionized, and the operating conditions. The ion ~Y~h~nge - 'Lane will be dependent upon the size of the ionized substance, if it can be transferred across the membrane under a reasonable operating potential. Other factors which will effect the determination of the type of membrane to be utilized include the operating temperature, the type of ion to be transferred (cation or anion), and the chemical effects of the substance on the membrane and vice versa. All of these parameters can readily be determined by one skilled in this art.
In detecting hydrogen, for example, the catalyst must be capable of ionizing the hydrogen: and may be 2030~6~
any one of a number of conventional catalysts utilized in electrolysis cells to ~ifi~C~ociate hydrogen. The preferred catalyst is based on a metal from the platinum family, such as ruthenium, rhodium, palladium, iridium, and platinum, with platinum black bonded with Teflon-, produced by Du Pont de Nemours, E. I. & Company, (metal lo~n~ of 4.0 mg/cm2) especially preferred; altho~l~h differant catalysts can be utilized. Variou~ ion ~Y~h~nge membranes can also be utilized, with Nafion- pro~uce~ by Du Pont de Nemours, Inc., preferred. The operating temperature for Nafion should not ~Ycee~ approximately 250~F.
Therefore, any device utilizing this particular membrane preferably operated above the freezing point lS of the stream, and below approximately 250~F.
As with the temperature, tha pressure and flow ratesof the stream can vary greatly. In order to detect the substance at various temperatures, pressures, and flow rates, the uu~uL readings ~ust be calibrated for the particular substance to be detected, and the system operating conditions.
To calibrate the system, the pressure, temperature, and flow rate are held constant for the desired conditions; while the stream cont~inin~ the substance is p~se~ through the detector. Once the stream exits the detector, it is place within a conventional device for measuring the substance.
Hydrogen, for example, can be placed within low pressure device which liberates the hydrogen, allowing the amount of hydrogen in the stream to ba measured.
The amount of substance determined by the detector is compared with the amount of substance actually in the stream. If, for instance, 72.0 percent of the ~030~6~
substance was detected with the detector, the detector rea~n~ must be ad~usted. The ad~u#tment consists of dividing the amount of substance detected by 0.72 to determine the actual amount of substance within the stream.
This process, which permit~ continuo~c monitoring of the subctance conc~ntration within a fluid stream, creates detection devices for discovering problems, or system fluctuations early. Also, since the substance is reintro~-~ce~ to the stream, the problem of disposing the test sample never arises, nor doe~ the problem of ac lating test samples within the system; the stream is essentially undisturbed by the p~ocess. Furthermore, if the stream is h- -,eneous, this determination is highly accurate; without invasive sampling.
This invention is particularly useful for detecting hydrogen in a water stream of a fuel cell/electroyler system where it is nec~ssAry to have a closed system and/or where the hydrogen must not PYcee~ a given maximum. For instance, where the water stream is int~nde~ for astronaut consumption, or where the water stream will be in~lol~ce~ to an oxygen stream, it can be important or even critical to keep the.~l~dLu~en content of the water to a mini~um.
Continou~ monitoring of the hyd-o~en concentration within the water stream will allow early detection of potential disasterous problems: enabling them to be avoided.
Example 1 The following pLoced~re can be utilized to detect hydrogen wlthin a water/hydrogen stream for a life support system which pro~uce~ approximately 9.08 pounds of oxygen per day. (refer to the Figure).
1. A water/hydrogen stream i9 inLLo~ ce~ to the feed chamber (3) of the detector at 22.0 cc/min., 120~F, and 160 psia.
2. The hydrogen within the str~am contacts a platinum black bon~s~ with Teflon-(metal lo~ing of 4.0 mg/cm ) catalyst at the anode ele~ode (13), and is catalytically ionized producing ions -~ and free electrons.
3. The ions are transported across the Nafion ion ~hAnge ' ane to the cathode electrode (15) under the influence of a DC potential maint~ine~
by the power source (0.50 volts).
by the power source (0.50 volts).
4. The free electrons pass through ths power source (7), and external electric circuit, to the cathode electrode (15). The current ia monitored with an ampere meter (17). The rea~inq is received in less than 1.0 secon~.
5. The ions and free ele~ons are recombined to form molec~ r hy~loyen at the cathode electrode (lS) where a platinum black hon~e~ with Teflon (metal loading of 4.0 mg/cm2) catalyst is present.
6. The molecular h~d~o~en is reintrod~lced into the stream, from which it was taken, in the reflow chamber (9). The reinL~ud~ction of the hydroyen into the stream ~L~verlls the detection operation from significantly disturbing the stream.
Example 2 203096~
The follow~ng procedure can be utllized to detect hydrogen within the water stream of a hydrogen/oxygen system for producing rocket propulsion reactants. The operating parameters for this system are: 3,000 psi, 120-F, and the water/hydrogen flow is 106 cc/min (oxygen and hydrogen flow to the system are 1.78 lbs/hr, and 0.22 lbs/hr, respectively).
The parameters in Example 1 can be ~ollowed.
Since the temperature of this system does not PYcePA
250-F, the ion ~YnhAnqe membrane iq Nafion. Platinum black bonded with Teflon (metal lo~Aing of 4.0 mg/cm2) catalyst is used at both electrodes.
Altholt~h this invention has been shown and described with respect to detailed ~ ~sAiments thereof, it will be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed inventionO
We claim:
Example 2 203096~
The follow~ng procedure can be utllized to detect hydrogen within the water stream of a hydrogen/oxygen system for producing rocket propulsion reactants. The operating parameters for this system are: 3,000 psi, 120-F, and the water/hydrogen flow is 106 cc/min (oxygen and hydrogen flow to the system are 1.78 lbs/hr, and 0.22 lbs/hr, respectively).
The parameters in Example 1 can be ~ollowed.
Since the temperature of this system does not PYcePA
250-F, the ion ~YnhAnqe membrane iq Nafion. Platinum black bonded with Teflon (metal lo~Aing of 4.0 mg/cm2) catalyst is used at both electrodes.
Altholt~h this invention has been shown and described with respect to detailed ~ ~sAiments thereof, it will be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed inventionO
We claim:
Claims (10)
1. A method of detecting ionizable substance in a stream, which comprises:
a. using a detector, said detector including a means for introducing and a means for removing said stream containing an ionizable substance, a current measuring device, a power source, a catalytic cathode electrode, a catalytic anode electrode, and an ion exchange membrane disposed therebetween;
b. introducing said stream containing said ionizable substance to the anode electrode via said means for introducing said stream;
c. applying and maintaining a potential across said ion exchange membrane from said power source;
d. ionizing said substance at said anode electrode, wherein ions and free electrons are produced;
e. transferring said ions across said ion exchange membrane to said cathode electrode;
f. passing said free electrons through said power source to said cathode electrode;
g. using said current measuring device to determine the current produced by the free electrons which pass through said power source, wherein said current measuring device is connected to said power source;
h. recombining said ions and said free electrons at the cathode electrode to produce the molecular form of said ionizable substance; and i. reintroducing the molecular substance to said stream in said means for removing said stream, wherein said stream flows first through said means for introducing said stream and then through said means for removing said stream;
whereby the current flow of the electrons across the power source is the same as the current flow of the ions across the ion exchange membrane, and wherein measurement of said current provides a measurement of the ionizable substance flow.
a. using a detector, said detector including a means for introducing and a means for removing said stream containing an ionizable substance, a current measuring device, a power source, a catalytic cathode electrode, a catalytic anode electrode, and an ion exchange membrane disposed therebetween;
b. introducing said stream containing said ionizable substance to the anode electrode via said means for introducing said stream;
c. applying and maintaining a potential across said ion exchange membrane from said power source;
d. ionizing said substance at said anode electrode, wherein ions and free electrons are produced;
e. transferring said ions across said ion exchange membrane to said cathode electrode;
f. passing said free electrons through said power source to said cathode electrode;
g. using said current measuring device to determine the current produced by the free electrons which pass through said power source, wherein said current measuring device is connected to said power source;
h. recombining said ions and said free electrons at the cathode electrode to produce the molecular form of said ionizable substance; and i. reintroducing the molecular substance to said stream in said means for removing said stream, wherein said stream flows first through said means for introducing said stream and then through said means for removing said stream;
whereby the current flow of the electrons across the power source is the same as the current flow of the ions across the ion exchange membrane, and wherein measurement of said current provides a measurement of the ionizable substance flow.
2. A method as in claim 1 wherein said ionizable substance is selected from the group which consists of hydrogen, sodium, fluorine, chlorine, oxygen, and bromine.
3. A method as in claim 1 wherein both of said catalytic anode and said catalytic cathode comprise a catalyst, and wherein said catalysts are based on a metal selected from the group consisting of ruthenium, rhodium, palladium, iridium, and platinum.
4. A method as in claim 1 wherein said current measuring device is an ampere meter.
5. A method as in claim 1 wherein said means for introducing and means for removing said stream comprises two chambers: whereby one chamber is on the anode electrode side of the ion exchange membrane, and the other chamber is on the cathode electrode side of the membrane.
6. Apparatus for detecting an ionizable substance in a stream comprising:
a. a means for introducing said stream containing said ionizable substance to the apparatus, said means for introducing constructed and arranged for allowing said stream to exit to a flow channel;
b. a catalytic anode electrode for ionizing said substance, producing ions and free electrons;
c. a catalytic cathode electrode for recombining said ions with said free electrons to return said substance to its molecular form and to reintroduce the reformed substance back into said stream;
d. an ion exchange membrane for transporting said ions from said anode electrode to said cathode electrode, wherein said ion exchange membrane is disposed between and in intimate contact with said anode electrode and said cathode electrode;
e. a power source for maintaining a potential across said ion exchange membrane and through which said free electrons pass, wherein said potential influences the flow of said ions from the anode electrode to the cathode electrode;
f. a current measuring device connected to said power source, wherein said current measuring device monitors the amount of electrons which pass through said power source; and g. a means for removing said stream containing said reintroduced substance from said apparatus, wherein said means for removing is constructed and arranged for accepting said stream from the flow channel and said stream passes through said means for introducing, enters the flow channel, passes through the flow channel, and enters said means for removing such that said means for introducing and said means for removing are in flow communication;
whereby the flow of the free electrons through the power source is proportional to the amount of ionizable substance within the stream.
a. a means for introducing said stream containing said ionizable substance to the apparatus, said means for introducing constructed and arranged for allowing said stream to exit to a flow channel;
b. a catalytic anode electrode for ionizing said substance, producing ions and free electrons;
c. a catalytic cathode electrode for recombining said ions with said free electrons to return said substance to its molecular form and to reintroduce the reformed substance back into said stream;
d. an ion exchange membrane for transporting said ions from said anode electrode to said cathode electrode, wherein said ion exchange membrane is disposed between and in intimate contact with said anode electrode and said cathode electrode;
e. a power source for maintaining a potential across said ion exchange membrane and through which said free electrons pass, wherein said potential influences the flow of said ions from the anode electrode to the cathode electrode;
f. a current measuring device connected to said power source, wherein said current measuring device monitors the amount of electrons which pass through said power source; and g. a means for removing said stream containing said reintroduced substance from said apparatus, wherein said means for removing is constructed and arranged for accepting said stream from the flow channel and said stream passes through said means for introducing, enters the flow channel, passes through the flow channel, and enters said means for removing such that said means for introducing and said means for removing are in flow communication;
whereby the flow of the free electrons through the power source is proportional to the amount of ionizable substance within the stream.
7. An apparatus as in claim 6 wherein both of said catalytic anode and catalytic cathode comprise a catalyst, and wherein said catalysts are based on a metal selected from the group consisting of ruthenium, rhodium, palladium, iridium, and platinum.
8. An apparatus as in claim 6 wherein said current measuring device is an ampere meter.
9. An apparatus as in claim 6 wherein said means for introducing said stream is a chamber.
10. An apparatus as in claim 6 wherein said means for removing said stream is a chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US446,031 | 1989-12-05 | ||
| US07/446,031 US5118398A (en) | 1989-12-05 | 1989-12-05 | Method and an apparatus for detecting ionizable substance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2030965A1 CA2030965A1 (en) | 1991-06-06 |
| CA2030965C true CA2030965C (en) | 1998-02-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002030965A Expired - Fee Related CA2030965C (en) | 1989-12-05 | 1990-11-13 | Ionizable substance detector |
Country Status (5)
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|---|---|
| US (1) | US5118398A (en) |
| EP (1) | EP0431565B1 (en) |
| JP (1) | JP3062254B2 (en) |
| CA (1) | CA2030965C (en) |
| DE (1) | DE69028495T2 (en) |
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| JPH07505952A (en) * | 1992-04-22 | 1995-06-29 | ザ ダウ ケミカル カンパニー | Electrochemical sensor device based on polymer film |
| US5411644A (en) * | 1993-11-03 | 1995-05-02 | Neukermans; Armand P. | Method of operated dual pump getter and oxidant sensor and regulator |
| US5650054A (en) * | 1995-01-31 | 1997-07-22 | Atwood Industries, Inc. | Low cost room temperature electrochemical carbon monoxide and toxic gas sensor with humidity compensation based on protonic conductive membranes |
| US5573648A (en) * | 1995-01-31 | 1996-11-12 | Atwood Systems And Controls | Gas sensor based on protonic conductive membranes |
| DE19517907C1 (en) * | 1995-05-16 | 1996-10-24 | Auergesellschaft Gmbh | Electrochemical solid electrolyte sensor for measuring chlorine |
| US6306285B1 (en) | 1997-04-08 | 2001-10-23 | California Institute Of Technology | Techniques for sensing methanol concentration in aqueous environments |
| US6036838A (en) * | 1997-11-15 | 2000-03-14 | Deutsches Zentrum Fuer Luft -Und Raumfahrt E.V. | Method for determining the substance conversion during electrochemical reactions and electrochemical unit |
| DE19750738C1 (en) * | 1997-11-15 | 1999-01-14 | Deutsch Zentr Luft & Raumfahrt | Material conversion determination in surface electrochemical reaction |
| DE19801117C1 (en) * | 1998-01-15 | 1999-01-07 | Forschungszentrum Juelich Gmbh | Quality testing of a flat element at limited test area |
| EP1156326A4 (en) | 1999-10-01 | 2003-03-12 | Matsushita Electric Ind Co Ltd | Carbon monoxide sensor |
| US20040229108A1 (en) * | 2002-11-08 | 2004-11-18 | Valdez Thomas I. | Anode structure for direct methanol fuel cell |
| US7282291B2 (en) * | 2002-11-25 | 2007-10-16 | California Institute Of Technology | Water free proton conducting membranes based on poly-4-vinylpyridinebisulfate for fuel cells |
| CN1752753B (en) * | 2004-09-22 | 2010-04-28 | 杭州生源医疗保健技术开发有限公司 | Ionic membrane microflow electroosmosis pump |
| FR2991506B1 (en) * | 2012-05-29 | 2015-03-20 | Commissariat Energie Atomique | PROCESS FOR MEASURING REPRODUCIBILITY OF N UNITARY ASSEMBLIES ION EXCHANGE MEMBRANE / ELECTRODES BY INTRODUCTION OF POLLUTANT AGENT |
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|---|---|---|---|---|
| US3864226A (en) * | 1972-10-19 | 1975-02-04 | Du Pont | Process for electrolyzing aqueous sodium or potassium ion solutions |
| DE2437395C3 (en) * | 1973-10-15 | 1979-02-08 | E.I. Du Pont De Nemours And Co., Wilmington, Del. (V.St.A.) | Film made from fluorine-containing polymers with side chains containing sulfonyl groups |
| US4030988A (en) * | 1973-12-17 | 1977-06-21 | E. I. Du Pont De Nemours And Company | Process for producing halogen and metal hydroxides with cation exchange membranes of improved permselectivity |
| US4171253A (en) * | 1977-02-28 | 1979-10-16 | General Electric Company | Self-humidifying potentiostated, three-electrode hydrated solid polymer electrolyte (SPE) gas sensor |
| US4123700A (en) * | 1977-11-14 | 1978-10-31 | General Electric Company | Potentiostated, self-humidifying, solid polymer electrolyte carbon monoxide dosimeter |
| US4227984A (en) * | 1979-03-01 | 1980-10-14 | General Electric Company | Potentiostated, three-electrode, solid polymer electrolyte (SPE) gas sensor having highly invariant background current characteristics with temperature during zero-air operation |
| DE3033796A1 (en) * | 1980-09-09 | 1982-04-22 | Bayer Ag, 5090 Leverkusen | ELECTROCHEMICAL SENSOR FOR DETECTING REDUCING GASES, ESPECIALLY CARBON MONOXIDE, HYDRAZINE AND HYDROGEN IN AIR |
| JPS5830688A (en) * | 1981-08-18 | 1983-02-23 | Kazunari Yamada | Sensor |
| FR2564624A1 (en) * | 1984-05-18 | 1985-11-22 | Icare Sa | Device providing the forced circulation of gas in sintered materials for gas detectors and analysers |
| JPS6118857A (en) * | 1984-07-06 | 1986-01-27 | Ngk Insulators Ltd | Manufacture of electrochemical cell |
| GB2169412B (en) * | 1984-12-31 | 1988-06-15 | Uop Inc | Chlorine detection |
| JPH065222B2 (en) * | 1985-05-09 | 1994-01-19 | 日本碍子株式会社 | Electrochemical device |
| US4795533A (en) * | 1985-07-10 | 1989-01-03 | Allied-Signal Inc. | Gas detection apparatus and method with novel three-component membrane |
| JPS62172257A (en) * | 1986-01-27 | 1987-07-29 | Figaro Eng Inc | Proton conductor gas sensor |
| US4797190A (en) * | 1986-10-06 | 1989-01-10 | T And G. Corporation | Ionic semiconductor materials and applications thereof |
| US4820386A (en) * | 1988-02-03 | 1989-04-11 | Giner, Inc. | Diffusion-type sensor cell containing sensing and counter electrodes in intimate contact with the same side of a proton-conducting membrane and method of use |
-
1989
- 1989-12-05 US US07/446,031 patent/US5118398A/en not_active Expired - Lifetime
-
1990
- 1990-11-13 CA CA002030965A patent/CA2030965C/en not_active Expired - Fee Related
- 1990-12-04 DE DE69028495T patent/DE69028495T2/en not_active Expired - Fee Related
- 1990-12-04 EP EP90123243A patent/EP0431565B1/en not_active Expired - Lifetime
- 1990-12-05 JP JP2405406A patent/JP3062254B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US5118398A (en) | 1992-06-02 |
| JPH03267753A (en) | 1991-11-28 |
| CA2030965A1 (en) | 1991-06-06 |
| DE69028495T2 (en) | 1997-04-24 |
| EP0431565A2 (en) | 1991-06-12 |
| EP0431565B1 (en) | 1996-09-11 |
| JP3062254B2 (en) | 2000-07-10 |
| DE69028495D1 (en) | 1996-10-17 |
| EP0431565A3 (en) | 1993-01-13 |
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