Solid state gas sensor and filter assembly

A potentiometric gas sensor for detecting the presence of a gas contaminant in a gas sample being monitored, said gas sensor comprising:

• a first electrically conductive element which interacts with said gas contaminant present in said gas sample;
• a second electrically conductive element which does not interact with said gas contaminant present in said gas sample;
• an ionically conductive substrate having said first and second electrically conductive elements mounted thereon;
• measuring circuitry connected to said first and second electrically conductive elements;
• and
• a filter layer through which said gas being sampled flows prior to being exposed to said first and second electrically conductive elements, said filter layer being a material selected from the group comprising microporous, nanoporous, and non-porous membranes, and chemically reactive materials and wherein said filter layer is constructed of a polymer membrane selected from the group consisting of cationic membranes, anionic membranes, and bipolar membranes.

A potentiometric gas sensor for detecting the presence of a gas contaminant in a gas sample being monitored, said gas sensor comprising:

• a first electrically conductive element which interacts with said gas contaminant present in said gas sample;
• a second electrically conductive element which does not interact with said gas contaminant present in said gas sample;
• an ionically conductive substrate having said first and second electrically conductive elements mounted thereon;
• measuring circuitry connected to said first and second electrically conductive elements;
• and
• a filter layer through which said gas being sampled flows prior to being exposed to said first and second electrically conductive elements, said filter layer being a material selected from the group comprising microporous, nanoporous, and non-porous membranes, and chemically reactive materials and said filter layer is mounted to said ionically conductive substrate to enclose said first electrically conductive element between said ionically conductive substrate and said filter layer and wherein said filter layer is a porous polymer membrane comprising a molecular sieve dispersed throughout an inert polymeric support and wherein said polymer membrane is a nonporous, inert polymeric support having zeolite powder dispersed throughout.

A potentiometric gas sensor for detecting the presence of a gas contaminant in a gas sample being monitored, said gas sensor comprising:

• a first electrically conductive element which interacts with said gas contaminant present in said gas sample;
• a second electrically conductive element which does not interact with said gas contaminant present in said gas sample;
• an ionically conductive substrate having said first and second electrically conductive elements mounted thereon;
• measuring circuitry connected to said first and second electrically conductive elements;
• and
• a filter layer through which said gas being sampled flows prior to being exposed to said first and second electrically conductive elements, said filter layer being a material selected from the group comprising microporous, nanoporous, and non-porous membranes, and chemically reactive materials, and wherein said layer of nanoporous membrane is selected from the group consisting of nanoporous alumina, polysulfone, and regenerated cellulose on a polymeric support.

A potentiometric gas sensor for detecting the presence of a gas contaminant in a gas sample being monitored, said gas sensor comprising:

• a first electrically conductive element which interacts with said gas contaminant present in said gas sample;
• a second electrically conductive element which does not interact with said gas contaminant present in said gas sample;
• an ionically conductive substrate having said first and second electrically conductive elements mounted thereon;
• measuring circuitry connected to said first and second electrically conductive elements;
• and
• a filter layer through which said gas being sampled flows prior to being exposed to said first and second electrically conductive elements, said filter layer being a material selected from the group comprising microporous, nanoporous, and non-porous membranes, and chemically reactive materials and said filter material is selected from the group consisting of microporous, nanoporous, permselective, and chemically reactive material wherein said nanoporous material is a membrane selected from the group consisting of nanoporous alumina, polysulfone, and regenerated cellulose on a polymeric support.

A potentiometric method for sensing the presence of a gas contaminant in a gas sample being monitored comprising the steps of:

• exposing an ion-conducting substrate having first and second electrically conductive elements mounted thereon with said gas sample for ionic conduction between said first and second electrically conductive elements;
• measuring a first voltage signal corresponding to the difference between said first and second electrically conductive electrodes, respectively;
• comparing said first voltage signal with a threshhold voltage signal;
• and
• outputting a trigger signal indicating the presence of said contaminant gas whenever said first voltage signal is less than said threshhold voltage.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ion-conducting substrate for providing ionic conduction in support of the electronic conduction disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said first ion-conducting substrate, said gas sensing electrode being disposed between said first ion-conducting substrate and said filter layer;
• a second ion-conducting ionically conductive substrate for providing ionic conduction in support of the electronic conduction disposed below said first ion-conducting substrate;
• at least one reference electrode disposed between a lower surface of said first ion-conducting substrate and an upper surface of said second ion-conducting substrate;
• and
• at least one environmental variable sensing electrode mounted to a lower surface of said second ion-conducting substrate.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ionically conductive substrate disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said ionically conductive substrate, said gas sensing electrode being disposed between said first ionically conductive substrate and said filter layer;
• a second ionically conductive substrate disposed below said first ionically conductive substrate;
• at least one reference electrode disposed between a lower surface of said first ionically conductive substrate and an upper surface of said second ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to a lower surface of said second ionically conductive substrate;
• and a porous, inert protective layer below said lower surface of said second ionically conductive substrate to cover said environmental variable sensing electrode, wherein said porous, inert protective layer is constructed of porous polypropylene or porous polyethylene.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ionically conductive substrate disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said ionically conductive substrate, said gas sensing electrode being disposed between said first ionically conductive substrate and said filter layer;
• a second ionically conductive substrate disposed below said first ionically conductive substrate;
• at least one reference electrode disposed between a lower surface of said first ionically conductive substrate and an upper surface of said second ionically conductive substrate, wherein said at least one environmental variable sensing electrode is a temperature/% RH compensator electrode.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ionically conductive substrate disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said ionically conductive substrate, said gas sensing electrode being disposed between said first ionically conductive substrate and said filter layer;
• a second ionically conductive substrate disposed below said first ionically conductive substrate;
• at least one reference electrode disposed between a lower surface of said first ionically conductive substrate and an upper surface of said second ionically conductive substrate;
• and
• a second environmental variable sensing electrode which outputs signals proportional to the pressure of said gas sample.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ionically conductive substrate disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said ionically conductive substrate, said gas sensing electrode being disposed between said first ionically conductive substrate and said filter layer;
• a second ionically conductive substrate disposed below said first ionically conductive substrate;
• at least one reference electrode disposed between a lower surface of said first ionically conductive substrate and an upper surface of said second ionically conductive substrate;
• and a third environmental variable sensing electrode which outputs signals proportional to the temperature of said gas sample.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ionically conductive substrate disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said ionically conductive substrate, said gas sensing electrode being disposed between said first ionically conductive substrate and said filter layer;
• a second ionically conductive substrate disposed below said first ionically conductive substrate;
• at least one reference electrode disposed between a lower surface of said first ionically conductive substrate and an upper surface of said second ionically conductive substrate;
• and a porous, inert protective layer below said lower surface of said second ionically conductive substrate to cover said environmental variable sensing electrode;
• and
• said filter layer is a material selected from the group consisting of microporous, nanoporous, permselective, and chemically reactive material and wherein said filter layer is constructed of a polymer membrane selected from the group consisting of cationic membranes, anionic membranes, and bipolar membranes;
• and
• wherein said filter layer is a porous polymer membrane comprising a molecular sieve dispersed throughout an inert polymeric support.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a filter layer;
• a first ionically conductive substrate disposed adjacent said filter layer and having at least one gas sensing electrode mounted to an upper surface of said ionically conductive substrate, said gas sensing electrode being disposed between said first ionically conductive substrate and said filter layer;
• a second ionically conductive substrate disposed below said first ionically conductive substrate;
• at least one reference electrode disposed between a lower surface of said first ionically conductive substrate and an upper surface of said second ionically conductive substrate;
• and a porous, inert protective layer below said lower surface of said second ionically conductive substrate to cover said environmental variable sensing electrode;
• and
• said filter layer is a material selected from the group consisting of microporous, nanoporous, permselective, and chemically reactive material and said layer of nanoporous material is a membrane selected from the group consisting of nanoporous alumina, polysulfone, and regenerated cellulose on a polymeric support.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom sections and openings through said top section;
• a filter layer disposed in the interior of said casing and dividing said interior into first and second chambers wherein said first chamber includes said top section of said casing and said second chamber includes said bottom section of said casing;
• an ionically conductive substrate disposed in said second chamber and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate whereby said ionically conductive substrate provides ionic conduction between said at least one gas sensing electrode and said reference electrode;
• and
• at least one environmental variable sensing electrode mounted to said upper surface of said ionically conductive substrate.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom sections and openings through said top section;
• a filter layer disposed in the interior of said casing and dividing said interior into first and second chambers wherein said first chamber includes said top section of said casing and said second chamber includes said bottom section of said casing;
• an ionically conductive substrate disposed in said second chamber and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to said upper surface of said ionically conductive substrate, said at least one environmental variable sensing electrode is a temperature/% RH compensator electrode.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom sections and openings through said top section;
• a filter layer disposed in the interior of said casing and dividing said interior into first and second chambers wherein said first chamber includes said top section of said casing and said second chamber includes said bottom section of said casing;
• an ionically conductive substrate disposed in said second chamber and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to said upper surface of said ionically conductive substrate,
• said gas sensing electrode is selected from the group consisting of a deposit of metal and ion-conductive electrolyte on a layer of carbon, an electronically conductive polymer, and a layer of fiber assemblies;
• said at least one environmental variable sensing electrode being constructed of the same material from which said gas sensing electrode is constructed;
• and
• means for isolating said at least one environmental variable sensing electrode from said gas sample in said second chamber.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom sections and openings through said top section;
• a filter layer disposed in the interior of said casing and dividing said interior into first and second chambers wherein said first chamber includes said top section of said casing and said second chamber includes said bottom section of said casing;
• an ionically conductive substrate disposed in said second chamber and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to said upper surface of said ionically conductive substrate, said filter layer is a material selected from the group consisting of microporous, nanoporous and permselective membranes, and chemically reactive material, said membranes are selected from the group consisting of cationic membranes, anionic membranes, and bipolar membranes;
• and
• wherein said filter layer is a cationic membrane comprised of sulfonic acid groups.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom sections and openings through said top section;
• a filter layer disposed in the interior of said casing and dividing said interior into first and second chambers wherein said first chamber includes said top section of said casing and said second chamber includes said bottom section of said casing;
• an ionically conductive substrate disposed in said second chamber and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to said upper surface of said ionically conductive substrate, said filter layer is a material selected from the group consisting of microporous, nanoporous, and permselective membranes, and chemically reactive material;
• said layer of nanoporous membranes is a membrane selected from the group consisting of nanoporous alumina, polysulfone, and regenerated cellulose on a polymeric support.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom sections and openings through said top section;
• a filter layer disposed in the interior of said casing and dividing said interior into first and second chambers wherein said first chamber includes said top section of said casing and said second chamber includes said bottom section of said casing;
• an ionically conductive substrate disposed in said second chamber and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to said upper surface of said ionically conductive substrate, said filter layer is a material selected from the group consisting of microporous, nanoporous, and permselective membranes, and chemically reactive material;
• and
• said filter layer is a cup shaped support containing said chemically reactive material and said cup shaped support has a meshed bottom surface and support sides extending outward from said cup support and attached to said casing to divide said casing into said first and second chambers.

A method for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising the steps of:

• directing said gas sample across a filter layer disposed in the interior of a casing to remove any interference gas from said gas sample;
• exposing an ionically conductive substrate having at least one gas sensing electrode and at least one environmental variable sensing electrode mounted to one surface thereof and a reference electrode mounted to a different surface thereof to said gas sample subsequent to the removal of said interference gas;
• compensating for changes in at least one environmental variable by subtracting a function of first voltage signal output by said at least one gas sensing electrode from a second voltage signal output by said at least one environmental variable sensing electrode to generate a compensated voltage signal output;
• generating a third voltage signal corresponding to the difference between said compensated voltage signal output;
• comparing said third voltage signal with a reference signal;
• and
• generating a trigger signal indicating the presence of said contaminant gas whenever said third voltage signal is less than said reference signal.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom section and openings through said top section into an interior of said casing;
• a chemical filter material dispersed throughout interior of said casing;
• an ionically conductive substrate disposed in said interior and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate whereby said ionically conductive substrate provides ionic conduction in support of the electronic conduction between said at least one gas sensing electrode and said reference electrode;
• and
• at least one environmental variable sensing electrode mounted to the upper surface of said ionically conductive substrate.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom section and openings through said top section into an interior of said casing;
• a chemical filter material dispersed throughout interior of said casing;
• an ionically conductive substrate disposed in said interior and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to the upper surface of said ionically conductive substrate, said at least one environmental variable sensing electrode is a temperature/% RH compensator electrode.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom section and openings through said top section into an interior of said casing;
• a chemical filter material dispersed throughout interior of said casing;
• an ionically conductive substrate disposed in said interior and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to the upper surface of said ionically conductive substrate, said temperature/% RH compensator electrode is a gas diffusion electrode.

A multiple layer potentiometric sensor device for detecting the presence of one or more gas contaminants in a gas sample being monitored, comprising:

• a casing with top and bottom section and openings through said top section into an interior of said casing;
• a chemical filter material dispersed throughout interior of said casing;
• an ionically conductive substrate disposed in said interior and having at least one gas sensing electrode mounted to an upper surface thereof;
• a reference electrode mounted to a lower surface of said ionically conductive substrate;
• and
• at least one environmental variable sensing electrode mounted to the upper surface of said ionically conductive substrate, said at least one environmental variable sensing electrode outputs a voltage signal proportional to changes in both temperature and % RH that is substantially equal to the voltage signal output of said gas sensing electrode in response to variations in both temperature and % RH.