Measuring sensor for detecting gaseous components

• US 5,281,324 A
• Filed: 04/05/1993
• Issued: 01/25/1994
• Est. Priority Date: 06/09/1990
• Status: Expired due to Fees

• Current Assignee: Dragerwerk AG
• Original Assignee: Dragerwerk AG
• Inventors: Kiesele, Herbert, Sohege, Jurgen
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Bell, Bruce F.
• Application Number:
  US08/042,664
• Time in Patent Office: 295 Days
• Field of Search: 204/412, 204/415, 204/431, 204/432
• US Class Current: 204/415
• CPC Class Codes: G01N 27/404 Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid , e.g. Clark-type oxygen sensors
• CPC Class Codes: G01N 27/4045 for gases other than oxygen

Abstract

The invention is directed to a measuring sensor for detecting gaseous components which operates in the diffusion limit current region. The measuring sensor includes a support body and has an electrolyte chamber partitioned by a diffusion membrane from the ambient containing the gaseous components. The measuring electrode of the measuring sensor is improved so that a simpler manipulation for covering the electrolyte chamber with a membrane is possible without endangering the mechanical stability of the membrane. During operation, the detection operation is intended to take place completely at that electrode surface which is in direct electrochemical exchange communication with the electrolyte supply. For this purpose, the coating is configured as an adherent layer to the support body so that it forms an impermeable adherence region in the lateral direction between coating and support body. A process for producing the measuring electrode is characterized in that the coating is adheringly applied to a front face of the support body which forms a closed surface. Thereafter, a membrane layer is applied to the coating and a break through for communicating with the electrolyte chamber is formed in the support body by removing a portion of the support body starting from a rear face thereof lying opposite the front face. The break through is formed by removing the portion of the support body through to the coating. In the completed measuring sensor, this permits the electrolyte from the electrolyte chamber to penetrate through the break through to the coating.

Claims

1. A measuring sensor for detecting gaseous components in the ambient, the measuring sensor comprising:

a support body having an end face and defining a chamber;

an electrolyte disposed in said chamber;

a permeable, electrically-conductive coating on said end face;

break through means extending from said chamber to said end face for permitting said electrolyte to penetrate to said coating;

said coating being applied to said end face so as to form an adhering interface;

a membrane separating said electrolyte from the ambient containing the gaseous components and being permeable to said gaseous components;

said membrane being impermeable to said electrolyte in a lateral direction between said support body and said coating and being applied to said coating so as to form an adhering connection with said coating;

an electrical signal lead connected to said coating so as to cause said coating to define a measuring electrode and have an electrochemically active surface at said interface; and

,

a counter electrode disposed in said electrolyte.

2. The measuring sensor of claim 1, said membrane layer being applied to said coating utilizing a polymerization process.

3. The measuring sensor of claim 1, said break through being defined by a plurality of channels.

4. The measuring sensor of claim 1, said break through being an etched break through formed in said support body.

5. The measuring sensor of claim 1, said coating being a galvanically precipitated coating.

6. The measuring sensor of claim 5, said support body being made of a first metal;

said coating being made of a second metal; and

, said second metal being more precious than said first metal.

7. The measuring sensor of claim 1, wherein said coating is an iridium oxide coating.

8. The measuring sensor of claim 7, wherein said membrane applied to said coating is a dielectric polymer film applied to said coating utilizing a parylene coating process.

9. The measuring sensor of claim 1, wherein said coating is a ruthenium oxide coating.

10. The measuring sensor of claim 9, wherein said membrane applied to said coating is a dielectric polymer film applied to said coating utilizing a parylene coating process.

11. The measuring sensor of claim 1, wherein said coating is made of a sputtered metal selected from the group consisting of iridium, ruthenium, platinum and palladium.

12. The measuring sensor of claim 11, wherein said membrane is a polymer film formed by plasma polymerization.

13. The measuring sensor of claim 11, wherein said membrane is a polymer film formed by electro-polymerization.

14. The measuring sensor of claim 1, wherein said coating is made of a galvanically deposited metal selected from the group consisting of iridium, ruthenium, platinum and palladium.

15. The measuring sensor of claim 14, wherein said membrane is a polymer film formed by plasma polymerization.

16. The measuring sensor of claim 14, wherein said membrane is a polymer film formed by electro-polymerization.