AUXILIARY GAS DIFFUSION ELECTRODES FOR DIAGNOSTICS OF ELECTROCHEMICAL GAS SENSORS

• US 20130087457A1
• Filed: 10/04/2012
• Published: 04/11/2013
• Est. Priority Date: 10/11/2011
• Status: Active Grant

• Current Assignee: Life Safety Distribution AG (Honeywell International Inc.)
• Original Assignee: Life Safety Distribution AG (Honeywell International Inc.)
• Inventors: Jones, Martin G., Chapples, John, PRATT, KEITH FRANCIS EDWIN
• Granted Patent: US 9,377,435 B2
• Time in Patent Office: Days
• US Class Current: 204/412
• CPC Class Codes: G01N 27/4045 for gases other than oxygen
• CPC Class Codes: G01N 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence

Abstract

An electrochemical gas sensor includes additional gas diffusion electrodes incorporated to carry out one or more diagnostic functions while the sensor is responding to a target gas. Members of a plurality of sensing and diagnostic electrodes can be switched by associated control circuits to intermittently sense a target gas while others intermittently sense a different gas. The diagnostic electrodes are in direct communication with the target gas that is entering the cell.

Claims

1. A gas sensor comprising:

a housing;

at least one electrode for sensing a target gas; and

at least one diagnostic electrode for sensing a different, gas wherein the diagnostic electrode is in direct communication with the incoming target gas; and

where the housing carries the electrodes.

2. A gas sensor as in claim 1 which includes control circuits coupled to the electrodes, the housing defines an internal gas cavity with the electrodes adjacent thereto.

3. A gas sensor as in claim 1 where the electrodes are co-planar and are at least in part, adjacent to one another.

4. A gas sensor as in claim 1 where the electrodes are distributed symmetrically relative to a center line.

5. A gas sensor as in claim 3 where the target gas sensing electrode and the diagnostic electrode are each formed with one of a cylindrical shape, or an annular shape.

6. A gas sensor as in claim 1 which includes a target gas diffusion barrier with the electrodes spaced therefrom, wherein a cavity is located, at least in part, between the target gas diffusion barrier and the at least one sensing electrode.

7. A gas sensor as in claim 1 where the housing defines an internal gas cavity which includes a plurality of spaced apart sensing electrodes.

8. A gas sensor as in claim 7 which includes control circuits coupled to the electrodes, where some electrodes function to sense a target gas, at least intermittently, and others function to sense a diagnostic gas, at least intermittently.

9. A gas sensor as in claim 8 where the control circuits switch electrodes from an active to an inactive stratus.

10. A gas sensor as in claim 8 where the electrodes are formed on a selected member co-planar with one another.

11. A gas sensor as in claim 5 where some of the electrodes function with the control circuits to intermittently sense the target gas and others function with the control circuits to intermittently sense the diagnostic gas.

12. A gas sensor as in claim 8 where the electrodes are formed with substantially the same shape, and are displaced around a common center line.

13. A gas sensor as in claim 8 where the diagnostic and gas sensing electrodes each have a surface area of a common size.

14. A gas sensor as in claim 11 where the electrodes are formed with substantially the same shape, and are displaced around a common center line and where the diagnostic and gas sensing electrodes each have a surface area of a common size.

15. A gas sensor comprising:

a housing that defines an internal gas diffusion region for an airborne target gas and an airborne diagnostic gas;

a plurality of electrodes, carried by the housing, adjacent to the gas diffusion region, the electrodes are in direct communication with the incoming target gas; and

control circuits coupled to the electrodes where some of the electrodes function with the control circuits to intermittently sense the target gas and others function with the control circuits to intermittently sense the diagnostic gas.

16. A gas sensor as in claim 15 where the electrodes each have a selected shape, are coplanar and formed on a substrate.

17. A gas sensor as in claim 16 where the electrodes are located adjacent to the diffusion region and surround a common line.

18. A gas sensor as in claim 17 where the control circuits select at least one electrode to sense a target gas for a first time interval and at least a second electrode to sense the target gas for a second time interval, and, where the control circuits select a third electrode to sense the diagnostic gas for a first diagnostic time interval and a fourth electrode to sense the diagnostic gas for a second diagnostic time interval.

19. A gas sensor as in claim 15 where in response to the control circuits, a selected electrode is used for sensing target gas during one time interval and for diagnostic gas sensing during another time interval.