Gas sensor and sensing device
First Claim
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1. A carbon dioxide gas sensor comprising a gas sensing device including a capacitor having spaced conductors;
- an aqueous electrolyte defining a relative dielectric constant and into which carbon dioxide dissolves and thereby changes the relative dielectric constant of said electrolyte, and wherein said spaced conductors are associated with but electrically insulated from said electrolyte;
means for holding said electrolyte adjacent said conductors; and
monitoring means for monitoring one of a resistive component and a capacitive component of said relative dielectric constant of said electrolyte independently of the one of said resistive and capacitive components.
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Abstract
A gas sensor comprises a substrate on which are mounted three cells. Each cell includes an interdigitated capacitor defined by a pair of comb structure, electrically conductive tracks with the fingers of the combs interleaved. The tracks of each capacitor are covered by an insulating and chemically inert protective coating of an electrolyte. A monitor monitors one of a resistive component and a capacitive component of the relative dielectric constant of the electrolyte independently of the other component.
40 Citations
19 Claims
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1. A carbon dioxide gas sensor comprising a gas sensing device including a capacitor having spaced conductors;
- an aqueous electrolyte defining a relative dielectric constant and into which carbon dioxide dissolves and thereby changes the relative dielectric constant of said electrolyte, and wherein said spaced conductors are associated with but electrically insulated from said electrolyte;
means for holding said electrolyte adjacent said conductors; and
monitoring means for monitoring one of a resistive component and a capacitive component of said relative dielectric constant of said electrolyte independently of the one of said resistive and capacitive components. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- an aqueous electrolyte defining a relative dielectric constant and into which carbon dioxide dissolves and thereby changes the relative dielectric constant of said electrolyte, and wherein said spaced conductors are associated with but electrically insulated from said electrolyte;
- 8. A carbon dioxide gas sensing device comprising a first interdigitated capacitor for connection to monitoring means, the capacitor including a set of interdigitated conductors, an aqueous electrolyte into which carbon dioxide dissolves, and an electrically insulating coating provided over said conductors to prevent the electrolyte and gas contacting the conductors, means for holding the electrolyte adjacent said conductors and separated by said insulating coating, wherein capacitance of the capacitor is affected by said electrolyte.
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17. A carbon dioxide gas sensing assembly comprising a first gas sensing device comprising a first interdigitated capacitor for connection to monitoring means, the capacitor having a capacitance and including a set of interdigitated conductors, an aqueous electrolyte into which carbon dioxide dissolves, and an electrically insulating coating provided over said conductors to prevent the electrolyte and gas contacting the conductors, means for holding said electrolyte adjacent said conductors and separated by said insulating coating, wherein the capacitance of the capacitor is affected by said electrolyte;
- and a second carbon dioxide gas sensing device substantially identical to said first gas sensing device except that carbon dioxide is prevented from accessing said electrolyte.
- View Dependent Claims (18, 19)
Specification