Electrochemical gas sensor with nonplanar diffusion membrane and electrode array

• US 6,695,959 B2
• Filed: 12/11/2002
• Issued: 02/24/2004
• Est. Priority Date: 02/25/2002
• Status: Expired due to Fees

• Current Assignee: Dragerwerk AG
• Original Assignee: Dragerwerk AG
• Inventors: Kiesele, Herbert
• Primary Examiner(s): Tung, T.
• Application Number:
  US10/316,617
• Publication Number:
  US 20030159930A1
• Time in Patent Office: 440 Days
• Field of Search: 204/412, 204/415, 204/431, 205/782, 205/782.5, 205/783
• US Class Current: 204/415
• CPC Class Codes: G01N 27/4045 for gases other than oxygen

Abstract

An electrochemical gas sensor, which has a substantially more compact design and is manufactured with a considerably reduced manufacturing effort. A conical, calotte-shaped, hemispherical or cylindrical outer housing is provided with gas admission openings (3, 203). A cover (8, 208) as well as a layer structure is provided with, from the outside to the inside, the diffusion membrane (4, 204) with the electrodes (5, 6, 7; 205, 206, 207) applied thereto in a planiform manner, a layer (11, 211) consisting of a mat material or a porous body, which accommodates the electrolyte, and an electrolyte space (10, 210), which is filled at least partially with the electrolyte.

Claims

1. An electrochemical gas sensor, comprising:

two electrodes;

a diffusion membrane;

an electrolyte,

an outer housing with a conical, hemispherical or cylindrical outer housing shape and with gas admission openings;

a cover connected with said outer housing; and

a layer structure comprising, from adjacent to said outer housing with gas admission openings in a direction away from said outer housing with gas admission openings to-the-inside, the diffusion membrane with the two electrodes applied thereto in a planiform manner and a layer of a mat material or a porous body, which accommodates the electrolyte, an electrolyte space filled at least partially with the electrolyte, the electrolyte space being defined by said layer structure adjacent to said layer of mat material or porous body.

2. An electrochemical gas sensor in accordance with claim 1, wherein said two electrodes include a measuring electrode and the electrochemical gas sensor further comprising another measuring electrode, said measuring electrode and said another measuring electrode being each a gas-specific measuring electrode for the simultaneous measurement of more than one measured gas.

3. An electrochemical gas sensor in accordance with claim 1, wherein the gas admission openings are located in an area of maximum distance from the cover.

4. An electrochemical gas sensor in accordance with claim 1, wherein the housing and said cover consist of a gas-impermeable material formed of one of polypropylene, polyethylene, polystyrene, polycarbonate, PMMA (polymethyl methacrylate), PSU (polysulfone), FEP (copolymer from hexafluoropropylene and tetrafluoropropylene) and PFA (perfluoroalkoxy polymer).

5. An electro chemical gas sensor in accordance with claim 1, wherein the housing is designed in the form of a hemisphere or a cylinder with a semicircular or U-shaped cross-sectional area.

6. An electrochemical gas sensor in accordance with claim 1, wherein the mat material or the porous body consists of one or more of a polymer material, glass, quartz fibers and ceramic fibers.

7. An electrochemical gas sensor in accordance with claim 1, wherein electric lines associated with the electrodes are applied to the diffusion membrane in the form of contact paths or strip conductors.

8. An electrochemical gas sensor in accordance with claim 7, wherein the electrodes and/or the electric lines are printed, sintered, sputtered or vapor-deposited on the diffusion membrane.

9. A method of forming an electrochemical gas sensor, comprising:

providing first and second electrodes, a diffusion membrane and an electrolyte,

forming an outer housing with a conical, hemispherical or cylindrical outer housing shape and with gas admission openings;

providing a cover; and

forming a layer structure within the outer housing with the layer structure comprising, from the outside to the inside, the diffusion membrane with the two electrodes applied thereto in a planiform manner and a layer of a mat material or a porous body, which accommodates the electrolyte, the layer structure adjacent to said mat material or a porous body forming an electrolyte space filled at least partially with the electrolyte.

10. An electrochemical gas sensor, comprising:

an outer housing with gas admission openings;

a cover connected with said outer housing;

an electrolyte; and

a layer structure comprising a diffusion membrane adjacent to said outer housing, two electrodes applied in a substantially planiform manner to said diffusion membrane on a side opposite said admission openings and a layer adjacent to said electrodes, said layer being of a mat material or a porous body which accommodates the electrolyte, said cover being connected to said outer housing to delimit an exterior of the electrochemical gas sensor with a conical, hemispherical or cylindrical exterior shape with said layer structure conforming to the shape of the outer housing and cooperating with said cover to define an electrolyte space adjacent to said layer of a mat material or a porous body, the electrolyte space being at least partially filled with a portion of said electrolyte.

11. An electrochemical gas sensor in accordance with claim 10, wherein said two electrodes include a measuring electrode and the electrochemical gas sensor further comprising another measuring electrode, said measuring electrode and said another measuring electrode being each a gas-specific measuring electrode for the simultaneous measurement of more than one measured gas with one measured gas-specific measuring electrode each.

12. An electrochemical gas sensor in accordance with claim 10, wherein the gas admission openings are located in an area of maximum distance from the cover.

13. An electrochemical gas sensor in accordance with claim 10, wherein the housing and said cover consist of a gas-impermeable material formed of one of polypropylene, polyethylene, polystyrene, polycarbonate, PMMA (polymethyl methacrylate), PSU (polysulfone), FEP (copolymer from hexafluoropropylene and tetrafluoropropylene) and PFA (perfluoroalkoxy polymer).

14. An electrochemical gas sensor in accordance with claim 10, wherein the housing is designed in the form of a hemisphere or a cylinder with a semicircular or U-shaped cross-sectional area.

15. An electrochemical gas sensor in accordance with claim 10, wherein the mat material or the porous body consists of one or more of a polymer material, glass, quartz fibers;

(and ceramic fibers.

16. An electrochemical gas sensor in accordance with claim 10, wherein electric lines associated with the electrodes are applied to the diffusion membrane in the form of contact paths or strip conductors.

17. An electrochemical gas sensor in accordance with claim 16, wherein the electrodes and/or the electric lines are printed, sintered, sputtered or vapor-deposited on the diffusion membrane.

18. A method of forming an electrochemical gas sensor, comprising:

providing an outer housing with gas admission openings;

providing a cover;

forming a layer structure on an inner surface of the outer housing with a diffusion membrane adjacent to said outer housing, two electrodes applied to said diffusion membrane in a planiform manner on a side of said diffusion membrane opposite said outer housing and a layer of a mat material or a porous body;

providing a cover;

providing electrolyte; and

disposing the outer housing with the layer structure in one of a conical, hemispherical or cylindrical outer housing shape with the layer structure defining an electrolyte space and with the layer structure conforming to the shape of the outer housing;

filling the electrolyte space with the electrolyte;

and closing the electrolyte space with the cover by connecting the cover to the outer housing.

19. A method in accordance with claim 18, wherein electric lines associated with the electrodes are applied to the diffusion membrane in the form of contact paths or strip conductors.

20. A method in accordance with claim 19, wherein the electrodes and/or the electric lines are printed, sintered, sputtered or vapor-deposited on the diffusion membrane.