Claims
- 1. Apparatus for detection, in a gas sample, of a gaseous component which is capable, in the presence of a catalytic agent, of dissociating to yield hydrogen ions or of combining with hydrogen ions comprising:
- (a) a thin film membrane which comprises a single phase blend of (i) from about 10% to about 70% by weight of a compound selected from the group consisting of heteropoly acids and salts thereof, where said heteropoly acids have the generic formula:
- A.sub.m [X.sub.x Y.sub.y O.sub.z ].multidot.n H.sub.2 O
- in which x is selected from the group consisting of boron, aluminum, gallium, silicon, germanium, tin, phosphorus, arsenic, antimony, bismuth, selenium, tellurium, iodine, and metals of the first, second, third and fourth transitional metal series of the periodic Table, said series including scandium, yttrium, lanthanum, actinium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, where Y is dissimilar from X and is selected from the group consisting of the metals of the first, second, third, and fourth transitional metal series of the periodic Table, A is selected from the group consisting of hydrogen, ammonium, sodium, potassium, lithium, rubidium, cesium, beryllium, magnesium, calcium, strontium and barium, m is an integer of from 1 to 10, y is an integer of from 6 to 12 based on x taken as 1, z is an integer of from 30 to 80, and n is an integer of from 3 to 100, and (ii) from about 90% to about 30% by weight of a polymer compatible with said compound which is selected from the group consisting of poly(vinyl alcohol), poly(vinyl fluoride), polyethylene oxide, polyethyleneimine, polyacryclic acid, polyethylene glycol, cellulose acetate, polyvinylmethylethyl ether, and phenol formaldehyde resins;
- (b) a membrance housing comprising a sample gas chamber and a reference gas chamber separated by a substantially imporous partition comprising said membrane, said membrane having a first surface in common with the sample gas chamber and a second surface in common with the reference gas chamber;
- (c) two separate portions of catalytic agent effective to promote dissociation and combination, one portion in contact with said first surface and one portion in contact with said second surface of said membrane;
- (d) means for forming electrical connection in operative contact with said catalytic agent at said first surface and with said catalytic agent at said second surface;
- (e) means for measuring EMF between said first and second surfaces;
- (f) means to supply sample gas to said sample gas chamber; and
- (g) means to provide an indication of the presence of hydrogen or of a gas capable of combining with hydrogen ions based on the measured EMF.
- 2. The apparatus of claim 1 further characterized in that said catalytic agent is selected from a group consisting of platinum, nickel, palladium, and alloys thereof.
- 3. The apparatus of claim 1 further characterized in that said catalytic agent is electrically conductive.
- 4. The apparatus of claim 1 further characterized in that said catalytic agent is porous to said gaseous component.
- 5. The apparatus of claim 1 further including means to adjust the operating temperature of said membrane housing.
- 6. The apparatus of claim 1 further including means to supply sample gas to the sample gas chamber and reference gas to the reference gas chamber.
- 7. The apparatus of claim 1 further including means to convert said EMF measurement to concentration.
- 8. The apparatus as set forth in claim 1 in which said acid or salt is present in said blend in an amount in the range of from about 30% to about 60% by weight of said blend.
- 9. The apparatus as set forth in claim 1 in which said polymer is present in said blend in an amount in the range of from about 70% to about 40% by weight of said blend.
- 10. The apparatus as set forth in claim 1 in which said membrane possesses a thickness of from about 0.1 to about 500 microns.
- 11. The apparatus as set forth in claim 1 in which said polymer comprises poly(vinyl alcohol) and said heteropoly acid comprises dodecamolybdophosphoric acid.
- 12. The apparatus as set forth in claim 1 in which said polymer comprises poly(vinyl alcohol) and said heteropoly acid comprises dodecamolybdophosphoric acid, where each is present in an amount of about 50% by weight.
- 13. A method of detecting, in a gas sample, a gaseous component capable, in the presence of a catalytic agent, of dissociating to yield hydrogen ions or of combining with hydrogen ions, said method comprises:
- (a) contacting said gas sample with a first surface of an imporous membrane comprising a solution blend of: (i) from about 10% to about 70% by weight of a heteropoly acid and salts thereof having the generic formula:
- A.sub.m [X.sub.x Y.sub.y O.sub.z ].multidot.n H.sub.2 O
- in which X is selected from the group consisting of boron, aluminum, gallium, silicon, germanium, tin, phosphorus, arsenic, antimony, bismuth, selenium, tellurium, iodine, and metals of the first, second, third and fourth transitional metal series of the Periodic Table, said series including scandium, yttrium, lanthanum, actinium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, and where Y is dissimilar from X and is selected from the group consisting of themetals of the first, second, third and fourth transitional metal series of the Periodic Table, A is selected from the group consisting of hydrogen, ammonium, sodium, potassium, lethium, rubidium, cesium, beryllium, magnesium, calcium, strontium and barium, m is an integer of from about 1 to 10, y is an integer of from 6 to 12 based on x being equal to 1, z is an integer of from 30 to 80 and n is an integer of from 3 to 100 and (ii) from about 90% to about 30% by weight of a polymer compatible with said compound selected from the group consisting of poly(vinyl alcohol), poly(vinyl fluoride), polyethylene oxide, polyethyleneimine, polyacrylic acid, polyethylene glycol, cellulose acetate, polyvinylmethyethyl ether and phenol formaldehyde resins having a first portion of catalytic agent in contact therewith effective to promote dissociation and combination;
- (b) contacting a reference gas which exhibits a substantially constant known hydrogen partial pressure with a second surface of said membrane having a second portion of catalyst in contact therewith, said membrane isolating said gas sample from said reference gas; and,
- (c) detecting EMF between means for forming electrical connection in operative contact with said first portion of catalytic agent at said first surface and with said second portion of catalytic agent at said second surface of said membrane.
- 14. The method of claim 13 further characterized in that said gaseous component is elemental hydrogen.
- 15. The method of claim 13 further characterized in that said gaseous component is elemental oxygen.
- 16. The method of claim 13 further characterized in that water is added to said gas sample and/or said reference gas before the gas contacts said membrane.
- 17. The method of claim 13 further characterized in that the concentration of said gaseous component in the gas sample is adjusted before the sample contacts said membrane.
- 18. The method of claim 13 further characterized in that the temperature of said gas sample and/or said reference gas is adjusted before said gas contacts said membrane.
Parent Case Info
This is a continuation-in-part of co-pending application Ser. No. 566,923, filed Dec. 29, 1983, now abandoned.
US Referenced Citations (11)
Non-Patent Literature Citations (3)
Entry |
Lundsgaard et al., "A Novel Hydrogen . . . Phosphate", Solid State Ionics 7 (1982) 53-56. |
Platinum Metal Review, Jan. 1983, vol. 27, No. 1, p. 8, "Hydrogen Detector Uses Silver-Palladium Probe". |
Instrumentation Tech., Aug. 1972, pp. 29-31, "A Thin-Film Hydrogen Sensor", by MacIntyre et al. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
566923 |
Dec 1983 |
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