Portable combustible gas detector

• US 20040145485A1
• Filed: 01/24/2003
• Published: 07/29/2004
• Est. Priority Date: 01/24/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Tice, Lee D.
• Granted Patent: US 6,987,459 B2
• Time in Patent Office: Days
• US Class Current: 340/632
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment devices for withdrawing samples in the gaseous state G01N1/22
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array
• CPC Class Codes: G01N 33/0047 Organic compounds
• CPC Class Codes: G01N 33/005 H2
• CPC Class Codes: G08B 21/16 Combustible gas alarms

Abstract

A portable detector of combustible or explosive gases incorporates a polymeric-type sensor or sensor array coupled to a programmed processor which carries out an evaluation of one or more signals from the sensor or array to evaluate the presence of combustible or explosive vapors. Non-polymeric sensors such as temperature sensors, humidity sensors and/or pressure sensors can also be incorporated and their outputs evaluated to compensate the outputs of the sensor or array of sensors. The detector can be housed in a sealed enclosure and energized by a battery.

Claims

1. A combustible gas detector comprising:

a portable, person wearable housing, the housing defines an internal region;

an array of polymeric-type combustible gas sensors carried in the region exposed to adjacent ambient atmosphere; and

executable instructions, carried in the region, for analyzing sensor outputs to establish the presence of a combustible concentration of the gas.

2. A detector as in claim 1 which includes a battery.

3. A detector as in claim 1 wherein the instructions carry out at least one of threshold analysis, profile analysis, principle component analysis, data clustering analysis or neural network analysis.

4. A detector as in claim 1 which includes a processor coupled to the sensors wherein the processor executes the instructions.

5. A detector as in claim 1 which includes at least one non-polymeric ambient condition sensor.

6. A detector as in claim 4 which includes at least one non-polymeric ambient condition sensor.

7. A detector as in claim 6 wherein the at least one sensor comprises one of a temperature sensor, a humidity sensor or a pressure sensor.

8. A detector as in claim 6 which includes at least one of an audible output device or a visual output device.

9. A detector as in claim 6 which includes at least one of a gas filter or a water condenser.

10. A portable combustible gas detector for sensing at least one gas capable of combustion, the detector comprising:

an enclosure;

at least one polymer sensor, carried by the enclosure, that senses a selected gas capable of combustion and generates at least a first signal indicative thereof;

at least one non-polymer sensor that senses a condition different than gas and generates at least a second signal indicative thereof;

a filter positioned between the at least one polymer sensor and the environment;

a processor with an input to receive the first signal and the second signal,

the processor includes at least one output port coupled to an indicating circuit to provide an indication of a concentration of the selected combustible gas.

11. A detector as in claim 10 wherein the indicating circuit comprises at least one of a visual or an audible output device.

12. A detector as in claim 10 which includes a plurality of different polymer-type gas sensors with different sensors generating different signals for the same concentration of the selected gas.

13. A detector as in claim 10 which includes a plurality of different polymer-type sensors with members of the plurality generating similar signals for the same concentration of the selected gas.

14. A detector as in claim 10 wherein the indicating circuit includes at least one of a character display, a light emitting diode or a light bulb.

15. A detector as in claim 10 wherein the gas is selected from a class of gases having an optical absorption peak in a wavelength between 3 microns and 4 microns.

16. A detector as in claim 10 wherein the at least one non-polymer sensor includes a temperature sensor.

17. A detector as in claim 16 wherein the temperature sensor includes a thermistor.

18. A detector as in claim 10 wherein the at least one non-polymer sensor includes a humidity sensor.

19. A detector as in claim 10 wherein the at least one non-polymer sensor includes a pressure sensor.

20. A detector as in claim 10 wherein the processor executes prestored instructions to compare at least the first signal to a concentration indicating threshold level.

21. A detector as in claim 20 wherein the processor compares the first signal to multiple levels with each indicating a different gas concentration.

22. A detector as in claim 10 wherein the filter comprises a membrane-type material that passes the selected gas but resists passage of liquid water.

23. A detector as in claim 10 wherein the enclosure carries an elastic, water excluding sealing element.

24. A detector as in claim 22 wherein the membrane-type material comprises, at least in part, a polymer-type material.

25. A detector as in claim 22 wherein the membrane-type material comprises a water excluding weave of material.

26. A detector as in claim 10 wherein a condenser is carried between the filter and polymer-type sensor to remove water vapors that pass through the filter.

27. A detector as in claim 26 wherein the condenser comprises metal that has a relatively high mass and thermal conductivity.

28. A detector as in claim 10 which includes pre-stored performance monitoring instructions executable by the processor.

29. A detector as in claim 10 which includes pre-stored lifetime monitoring instructions executable by the processor.

30. A portable combustible gas detector for sensing at least one gas capable of combustion when in a predetermined concentration in a region comprising:

a multi-part enclosure;

at least one polymer sensor, carried in the enclosure that senses a selected gas capable of combustion and generates a first signal indicative thereof;

at least one non-polymer sensor that senses a condition different than the gas and generates at least a second signal indicative thereof;

a filter that is positioned between the at least one polymer sensor and the environment to protect the one polymer sensor from particulates and water in the environment;

a sealing element between enclosure parts to block water from entering into the enclosure;

a processor with an input to receive the first signal and the second signal;

instructions, executable by the processor, responsive to at least both signals for establishing the presence of the selected gas in accordance with a selected criterion,

wherein the processor includes at least one output coupled to an indicating element to provide an indication representative of the concentration of the selected gas.

31. A combustible gas detector comprising:

at least one polymeric-type sensor of a selected combustible gas,

first circuitry to compare an output of the sensor to at least one threshold indicative of a pre-selected fraction of an explosive concentration of the gas; and

second circuitry to monitor detector performance.

32. A detector as in claim 31 which includes an environmental condition compensating sensor with an output coupled to the first circuitry for compensating the output of the at least one sensor.

33. A detector as in claim 31 wherein the at least one sensor, the first and second circuitry are carried in a sealed housing along with a source that provides sufficient energy for only a selected operational life-time.

34. A detector as in claim 33 which includes life-time monitoring circuitry.

35. A portable combustible gas detector comprising:

a housing defining at least one internal region wherein the housing has at least one gas permeable inlet to enable combustible gases in the adjacent ambient atmosphere to enter the at least one internal region,

the combustible gases at least partially absorb light energy in the three micron to four micron wavelength range;

an array of polymeric-type gas sensors carried in the at least one region;

a processor with executable instructions, carried within the housing, for analyzing outputs to establish the presence of a combustible gas;

an indicator indicating the presence of a combustible gas.

36. A portable combustible gas detector as in claim 35 wherein the array of polymeric-type gas sensors and the processor are attached to a common element within the housing.

37. A portable combustible gas detector as in claim 36 wherein the common element is a printed circuit board.