SENSOR INTERROGATION

• US 20130186777A1
• Filed: 03/12/2013
• Published: 07/25/2013
• Est. Priority Date: 10/14/2011
• Status: Active Grant

• Current Assignee: Mine Safety Appliances Co LLC (MSA Safety, Inc.)
• Original Assignee: Mine Safety Appliances Co LLC (MSA Safety, Inc.)
• Inventors: Scheffler, Towner B., Brown, Michael A., Davis, Brian Keith
• Granted Patent: US 10,908,111 B2
• Time in Patent Office: Days
• US Class Current: 205/785.5
• CPC Class Codes: G01N 27/26 by investigating electrochemical variables; by using electrolysis or electrophoresis
• CPC Class Codes: G01N 27/4175 Calibrating or checking the analyser
• CPC Class Codes: G01N 33/007 Arrangements to check the analyser calibrating gas analysers G01N33/0006
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A system includes a system housing including an inlet, at least one gas sensor responsive to a first analyte gas other than oxygen within the system housing and in fluid connection with the inlet, and a sensor responsive to oxygen within the system housing and in fluid connection with the inlet. The sensor responsive to oxygen is formed to be chemically separate from the at least one gas sensor responsive to the first analyte gas other than oxygen. The sensor responsive to oxygen is responsive to a change in the concentration of oxygen arising from creation of a driving force in the vicinity of the inlet to provide an indication of a state of a transport path between the inlet of the system and the at least one gas sensor responsive to the first analyte gas other than oxygen.

Claims

1. A system, comprising:

a system housing comprising an inlet;

at least one gas sensor responsive to a first analyte gas other than oxygen within the system housing and in fluid connection with the inlet, and

a sensor responsive to oxygen within the system housing and in fluid connection with the inlet, the sensor responsive to oxygen being formed to be chemically separate from the at least one gas sensor responsive to the first analyte gas other than oxygen, the sensor responsive to oxygen being responsive to a change in the concentration of oxygen arising from creation of a driving force in the vicinity of the inlet to provide an indication of a state of a transport path between the inlet of the system and the at least one gas sensor responsive to the first analyte gas other than oxygen.

2. The system of claim 1 wherein the driving force comprises application of exhaled breath or closing of the inlet from fluid connection with the environment surrounding the housing.

3. The system of claim 1 wherein the sensor responsive to oxygen comprises an electrochemically active electrode responsive to oxygen.

4. The system of claim 1 wherein the sensor responsive to oxygen is non-analytically responsive to oxygen.

5. The system of claim 1 further comprising an electrochemical gas sensor analytically responsive to oxygen within the housing and in fluid connection with the inlet, the electrochemical gas sensor analytically responsive to oxygen being formed separately from the at least one gas sensor responsive to the first analyte gas other than oxygen and the sensor responsive to oxygen.

6. The system of claim 1 further comprising a system to electronically interrogate at least one gas sensor responsive to the at least one analyte gas other than oxygen to test the functionality thereof to detect the at least one analyte gas other than oxygen.

7. The system of claim 1 wherein the at least one gas sensor responsive to the at least one analyte gas other than oxygen is an electrochemical gas sensor, the system further comprising:

a system to simulate the presence of the analyte gas electronically in operative connection with the electrochemical gas sensor responsive to the at least one analyte gas other than oxygen; and

a system to measure a response of the electrochemical gas sensor responsive to the at least one analyte gas other than oxygen to the electronic simulation.

8. The system of claim 7 wherein a constant current is caused to flow between a first working electrode and a counter electrode of the electrochemical gas sensor responsive to the at least one analyte gas other than oxygen and the measured response is a potential difference.

9. The system of claim 7 wherein a constant potential difference is maintained between a first working electrode and a counter electrode of the electrochemical gas sensor responsive to the at least one analyte gas other than oxygen and the measured response is a current.

10. The system of claim 7 wherein the electrochemical gas sensor responsive to the at least one analyte gas other than oxygen is an amperometric sensor.

11. The system of claim 7 further comprising an electrochemical gas sensor analytically responsive to oxygen within the housing and in fluid connection with the inlet, the electrochemical gas sensor analytically responsive to oxygen being formed separately from the electrochemical gas sensor responsive to the at least one analyte gas other than oxygen and the sensor responsive to oxygen.

12. The system of claim 1 further comprising a pump in fluid connection with the inlet to pump gas from the ambient atmosphere into the housing via the inlet.

13. The system of claim 12 further comprising a system to detect a pump fault.

14. A method of fabricating a system, comprising

providing a system housing which comprises an inlet;

disposing at least one gas sensor responsive to a first analyte gas other than oxygen within the system housing and in fluid connection with the inlet, and

disposing a sensor responsive to oxygen within the system housing and in fluid connection with the inlet, the sensor responsive to oxygen being formed to be chemically separate from the at least one gas sensor responsive to the first analyte gas other than oxygen, the sensor responsive to oxygen being responsive to a change in the concentration of oxygen arising from creation of a driving force in the vicinity of the inlet to provide an indication of a state of a transport path between the inlet of the system and the at least one gas sensor responsive to the first analyte gas other than oxygen.

15. A system, comprising:

a first gas sensor responsive to a first analyte gas,

a second gas sensor responsive to the first analyte gas, and

a control system to operate the first gas sensor in a sensing mode wherein a signal from the first gas sensor is representative of a concentration of the first analyte gas measured by the first gas sensor and in an interrogation mode wherein the first gas sensor is interrogated to test the functionality of the first gas sensor and to operate the second gas sensor in a sensing mode wherein a signal from the second gas sensor is representative of a concentration of the first analyte gas measured by the second gas sensor and in an interrogation mode wherein the second gas sensor is interrogated to test the functionality of the second gas sensor, the control system placing the first gas sensor in the interrogation mode only if the second gas sensor is in the sensing mode and placing the second gas sensor the interrogation mode only if the first gas sensor is in the sensing mode.

16. The system of claim 15 wherein the first sensor is a first electrochemical sensor and the second sensor is a second electrochemical gas sensor.

17. The system of claim 16 further comprising:

a system to simulate the presence of the analyte gas electronically in operative connection with the first electrochemical gas sensor to interrogate the first electrochemical gas sensor during the interrogation mode and in operative connection with the second electrochemical gas sensor to interrogate the second electrochemical gas sensor during the interrogation mode; and

a system to measure a response of the first electrochemical gas sensor to the electronic simulation and to measure a response of the second electrochemical gas sensor to the electronic simulation.

18. A method of operating a sensor including a first gas sensor responsive to a first analyte gas, and a second gas sensor responsive to the first analyte gas, comprising:

operating the first gas sensor in a sensing mode wherein a signal from the first gas sensor is representative of a concentration of the first analyte gas measured by the first gas sensor and in an interrogation mode wherein the first gas sensor is interrogated to test the functionality of the first gas sensor;

operating the second gas sensor in a sensing mode wherein a signal from the second gas sensor is representative of a concentration of the first analyte gas measured by the second gas sensor and in an interrogation mode wherein the second gas sensor is interrogated to test the functionality of the second gas sensor; and

placing the first gas sensor in the interrogation mode only if the second gas sensor is in the sensing mode and placing the second gas sensor the interrogation mode only if the first gas sensor is in the sensing mode.

19. The method of claim 18 wherein the first sensor is a first electrochemical sensor and the second sensor is a second electrochemical gas sensor.

20. The method of claim 19 further comprising:

simulating the presence of the analyte gas electronically during the interrogation mode of the first electrochemical gas sensor to interrogate the first electrochemical gas sensor;

simulating the presence of the analyte gas electronically during the interrogation mode of the second sensor to interrogate the second electrochemical gas sensor;

measuring a response of the first electrochemical gas sensor to the electronic simulation thereof; and

measuring a response of the second electrochemical gas sensor to the electronic simulation thereof.