DEVICE AND METHOD FOR MONITORING AN ELECTROCHEMICAL GAS SENSOR

• US 20090242398A1
• Filed: 03/27/2008
• Published: 10/01/2009
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: Sensor Electronics Corp.
• Original Assignee: Sensor Electronics Corp.
• Inventors: Smith, Patrick G.
• Granted Patent: US 8,097,146 B2
• Time in Patent Office: Days
• US Class Current: 204/401
• 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 33/007 Arrangements to check the analyser calibrating gas analysers G01N33/0006

Abstract

An electrochemical gas sensor testing device that includes a test signal generator that generates a multiplexed signal that includes a first test signal that includes alternating current (AC) and is free from a direct current (DC) component and a second signal that includes a DC bias voltage, an electrochemical cell that includes a counter electrode, a sensing electrode, and an electrolyte, the counter electrode and the sensing electrode being in electrical communication with the electrolyte and each other, the counter electrode being in electrical communication with the signal generator to receive the multiplexed signal generated by the signal generator, and a processor that receives an AC signal from the sensing electrode and that analyzes the AC signal.

Claims

1. An electrochemical gas sensor testing device comprising:

a signal generator that generates a multiplexed signal comprising a first test signal comprising alternating current (AC) and being free from a direct current (DC) component, and a second signal comprising a DC bias voltage;

an electrochemical cell comprising

a counter electrode,

a sensing electrode, and

an electrolyte,

the counter electrode and the sensing electrode being in electrical communication with the electrolyte and each other,

the counter electrode being in electrical communication with the signal generator to receive the multiplexed signal generated by the signal generator; and

a processor that receives an AC signal from the sensing electrode and that analyzes the AC signal.

2. The device of claim 1 further comprising a first filter that transmits alternating current and blocks direct current.

3. The device of claim 1 further comprising a first filter that blocks alternating current and transmits direct current.

4. The device of claim 2 further comprising a second filter that blocks alternating current and transmits direct current.

5. The device of claim 1, wherein the processor simultaneously analyzes a DC signal corresponding to the concentration of gas present in the electrochemical cell and the AC signal.

6. The device of claim 1, wherein the processor compares a first AC signal that corresponds to the AC test signal to a second AC signal that corresponds to the AC test signal.

7. The device of claim 1, wherein a single signal generator generates both the AC test signal and the DC bias voltage.

8. The device of claim 7, wherein the single signal generator is a potentiometer.

9. The device of claim 7, wherein the single signal generator is a variable gain amplifier.

10. The device of claim 1, wherein the processor instructs the signal generator to generate the test signal.

11. A method of testing an electrochemical gas sensor, said method comprising:

simultaneously applying an alternating current (AC) test signal and a direct current (DC) bias voltage to a counter electrode of an electrochemical gas sensor, the electrochemical gas sensor comprising

a sensing electrode,

an electrolyte, and

the counter electrode;

transmitting an AC test signal from the sensing electrode to a processor;

analyzing the AC signal received by the processor; and

determining whether or not the electrochemical cell is functioning.

12. The method of claim 11 further comprising comparing at least one frequency of an AC test signal transmitted to the processor at a first time to the same at least one frequency of an AC signal transmitted to the processor at a second time later than the first time.

13. The method of claim 11 further comprising simultaneously analyzing a DC signal corresponding to the concentration of a gas present in the electrochemical cell and the AC signal corresponding to the AC test signal.

14. The method of claim 11, wherein said processor simultaneously receives a DC signal corresponding to the concentration of a gas present in the electrochemical cell and an AC signal corresponding to the AC test signal.

15. The method of claim 11 further comprising storing a signal corresponding to the AC test signal.

16. The method of claim 15 further comprising comparing a received AC signal corresponding to the AC test signal to the stored AC test signal.

17. The method of claim 14 further comprising comparing a frequency of a received AC signal corresponding to the AC test signal to the stored signal.

18. The method of claim 11, wherein when no AC signal is received by the processor, a signal is generated indicating that the cell is not functioning properly.

19. The method of claim 11, wherein said AC test signal comprises multiple frequencies.

20. The method of claim 11, wherein said AC test signal comprises constant frequency and amplitude.

21. The method of claim 11 further comprising applying the AC test signal continuously to said electrochemical cell.

22. An electronic circuit comprising:

an electrochemical cell; and

a single signal generator that applies an AC test signal and a DC bias voltage to the electrochemical cell.

23. The electronic circuit of claim 22, wherein said signal generator applies the AC test signal and the DC bias voltage simultaneously to the electrochemical cell.

24. The electronic circuit of claim 22, wherein said signal generator is a variable gain amplifier.

25. The electronic circuit of claim 22, wherein said signal generator is a potentiometer.

26. The electronic circuit of claim 22 further comprising a processor that instructs the signal generator to generate an AC test signal.