CARBON DIOXIDE SENSOR

• US 3,673,069 A
• Filed: 05/03/1971
• Issued: 06/27/1972
• Est. Priority Date: 05/03/1971
• Status: Expired due to Term

• Current Assignee: Leonard W. Niedrach, William H. Stoddard Jr
• Original Assignee: Leonard W. Niedrach, William H. Stoddard Jr
• Inventors: Niedrach, Leonard W., Stoddard, William H. Jr.
• Primary Examiner(s): Tung, T.
• Application Number:
  US05/139,674
• Time in Patent Office: 421 Days
• Field of Search: 204/1T,195G,195P
• US Class Current: 204/414
• CPC Class Codes: G01N 27/4162 investigating the composition of gases, by the influence exerted on ionic conductivity in a liquid conductometry in general G01N27/06; amperometric gas sensors G01N27/404

Abstract

A carbon dioxide sensor has a first electronically conductive metallic base member, an electrochemically active region of a continuous glaze of pH sensing glass in electrical contact with a portion of the base member, a second electronically conductive metallic base member, a second electrochemically active region of silver and silver halide in electrical contact with the second base member, a first layer of electrical insulation disposed between the first and second base members, a second layer of electrical insulation disposed over the second base member, an immobilized electrolyte contacting both electrochemically active regions, and an outer sheath of carbon dioxide permeable, ionimpermeable diffusion barrier material encapsulating at least the electrochemically active regions and the electrolyte.

Claims

2. A carbon dioxide sensor as in claim 1, in which the second base member surrounds at least partially the first base member, a first layer of electrical insulation is disposed between the base members and a second layer of electrical insulation is disposed over the second base member.

3. A carbon dioxide sensor as in claim 2, in which the first base member is a palladium wire, the first electrochemically active region is pH sensitive glass, the second base member is silver, the second electrochemically active region is silver and silver chloride, the electrolyte is an immobilized aqueous solution containing chloride ions and bicarbonate ions, the first insulation is non-pH sensitive glass, and the second insulation and diffusion barrier are silicone-polycarbonate.

4. A carbon dioxide sensor as in claim 2, in which the first base member is a palladium wire, the first electrochemically active region is pH sensitive glass, the second base member is silver, the second electrochemically active region is silver and silver chloride, the electrolyte is quaternized polystyrene partially in its bicarbonate form and partially in its chloride form, the first insulation is non-sensitive glass, and the second insulation and diffusion barrier are silicone-polycarbonate.

5. A carbon dioxide sensor as in claim 1, in which the first electronically conductive metallic base member is a palladium wire with an external coating of silver.

6. A carbon dioxide sensor as in claim 1, in which the immobilized electrolyte is an anion exchange resin.