Method and device for detecting reducing gas using semiconductor gas sensor

Claim 1

A device for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor upon exposure thereto, comprising: a first chamber housing a first gas sensor of said semiconductor type, said first chamber having a first input means for inputting gas to be sampled or air, and a first output means for exhausting the inputted gas or air; a second chamber housing a second gas sensor of said semiconductor type, said second chamber having a second input means for inputting gas to be sampled or air, and a second output means for exhausting the inputted gas or air; means operatively connected to said first and second input means for inputting air; means operatively connected to said first and second input means for inputting gas; a flow control means connected between said first and second chambers, said air inputting means and said gas inputting means for controlling the flow of gas and air to said first and second chamber, wherein said flow control means permits either gas or air to flow through said first chamber and permits either gas or air to flow through said second chamber; and a microprocessor means connected to said first and second sensors for controlling said sensors and for converting output signals from said first and second sensors to a readable format indicative of the content of the oxygen depleting gas, and connected to said flow control means for controlling said flow control means to permit either gas or air to said first and second chambers.

Claim 2

A device for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor upon exposure thereto, comprising: a first chamber housing a first gas sensor of said semiconductor type, said first chamber having a first input means for inputting gas to be sampled or air, and a first output means for exhausting the inputted gas or air; a second chamber housing a second gas sensor of said semiconductor type, said second chamber having a second input means for inputting gas to be sampled or air, and a second output means for exhausting the inputted gas or air; means operatively connected to said first and second input means for inputting air; means operatively connected to said first and second input means for inputting gas; a flow control means connected between said first and second chambers, said air inputting means and said gas inputting means for controlling the flow of gas and air to said first and second chamber, wherein said flow control means permits either gas or air to flow through said first chamber and permits either gas or air to flow through said second chamber; and a microprocessor means connected to said first and second sensors for controlling said sensors and for converting output signals from said first and second sensors to a readable format indicative of the content of the oxygen depleting gas, and connected to said flow control means for controlling said flow control means to permit either gas or air to said first and second chambers.

Claim 11

A device for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor upon exposure thereto, comprising: a first chamber having a first gas sensor of said semiconductor type which outputs a signal in response to exposure to the gas which depletes oxygen from said first sensor; a first input means for inputting gas or air into said first chamber; a first output means for exhausting the inputted gas or air out of said first chamber; a second chamber having a second gas sensor of said semiconductor type which outputs a signal in response to exposure to said oxygen depleting gas; a second input means for inputting gas or air into said second chamber; a second output means for exhausting the inputted gas or air out of said second chamber; means for inputting air source to said first and second chamber via said first and second input means; means for inputting gas source to said first and second chamber via said first and second input means; a first flow control means having a first flow output means and a first pair of flow input means, said first flow output means being connected to said first input means of said first chamber; one of said first pair of flow input means connected to said air source inputting means; and the other of said first pair of flow input means connected to said gas source inputting means, wherein said first flow control means permits either gas or air to flow through said first chamber; a second flow control means having a second flow output means and a second pair of flow input means, said second flow output means being connected to said second input means of said second chamber; one of said second pair of flow input means connected to said air source means; and said other of said second pair of flow input means connected to said gas source inputting means, wherein said second flow control means permits either gas or air to flow through said second chamber; a control means connected to said first and second sensors for controlling said first and second sensors and for converting output signals from said first and second sensors to a readable format indicative of the content of said oxygen depleting gas, connected to said first flow control means, said second flow control means and connected to said air source inputting means for controlling air and gas flow through said first and second chambers, wherein said control means permits said first flow control means to flow gas through said first chamber while permitting said second flow control means to flow air through said second chamber for a first predetermined duration; and after said first predetermined duration, said microprocessor means permits said second flow control means to flow gas through said second chamber for a second predetermined duration while said first chamber remains flowing with gas; after said second predetermined duration, said microprocessor permits said first flow control means to flow air through said first chamber while said second chamber remains flowing with gas for said first predetermined duration; and after said first predetermined duration, said microprocessor permits said first flow control means to flow gas through said first chamber while said second chamber remains flowing with gas for said second predetermined period; and repeatedly alternating the flow of gas and air to said first and second chambers for said first predetermined duration and gas-up for said second predetermined duration; and a display for displaying the oxygen depleting gas content from either said first and second sensors.

Claim 12

A device for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor upon exposure thereto, comprising: a first chamber having a first gas sensor of said semiconductor type which outputs a signal in response to exposure to the gas which depletes oxygen from said first sensor; a first input means for inputting gas or air into said first chamber; a first output means for exhausting the inputted gas or air out of said first chamber; a second chamber having a second gas sensor of said semiconductor type which outputs a signal in response to exposure to said oxygen depleting gas; a second input means for inputting gas or air into said second chamber; a second output means for exhausting the inputted gas or air out of said second chamber; means for inputting air source to said first and second chamber via said first and second input means; means for inputting gas source to said first and second chamber via said first and second input means; a first flow control means having a first flow output means and a first pair of flow input means, said first flow output means being connected to said first input means of said first chamber; one of said first pair of flow input means connected to said air source inputting means; and the other of said first pair of flow input means connected to said gas source inputting means, wherein said first flow control means permits either gas or air to flow through said first chamber; a second flow control means having a second flow output means and a second pair of flow input means, said second flow output means being connected to said second input means of said second chamber; one of said second pair of flow input means connected to said air source means; and said other of said second pair of flow input means connected to said gas source inputting means, wherein said second flow control means permits either gas or air to flow through said second chamber; a control means connected to said first and second sensors for controlling said first and second sensors and for converting output signals from said first and second sensors to a readable format indicative of the content of said oxygen depleting gas, connected to said first flow control means, said second flow control means and connected to said air source inputting means for controlling air and gas flow through said first and second chambers, wherein said control means permits said first flow control means to flow gas through said first chamber while permitting said second flow control means to flow air through said second chamber for a first predetermined duration; and after said first predetermined duration, said microprocessor means permits said second flow control means to flow gas through said second chamber for a second predetermined duration while said first chamber remains flowing with gas; after said second predetermined duration, said microprocessor permits said first flow control means to flow air through said first chamber while said second chamber remains flowing with gas for said first predetermined duration; and after said first predetermined duration, said microprocessor permits said first flow control means to flow gas through said first chamber while said second chamber remains flowing with gas for said second predetermined period; and repeatedly alternating the flow of gas and air to said first and second chambers for said first predetermined duration and gas-up for said second predetermined duration; and a display for displaying the oxygen depleting gas content from either said first and second sensors.

Claim 16

A method for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor in gas to be sampled, lowering electrical resistance across the semiconductor gas sensor upon exposure thereto, comprising the steps of: a) exposing a first gas detecting sensor of said semiconductor type to gas to be sampled to detect the oxygen depleting gas content continuously for a first predetermined duration and for another second predetermined duration; b) exposing a second gas detecting sensor of said semiconductor type to ambient air during said first predetermined duration in step a) and exposing said second gas detecting sensor to said gas during said first and second predetermined duration in step a); c) reading the electrical resistance across said first sensor to determine the content of said oxygen depleting gas during said first and second predetermined durations in step a); d) maintaining exposure of said second sensor to said gas for another first and second predetermined durations; e) reading the electrical resistance across said second sensor to determine the content of said oxygen depleting gas during said first and second predetermined durations in step d); f) exposing said first sensor to ambient air to remove any gas residue and to replenish said first sensor with oxygen depleted therefrom during said first predetermined duration in step d) and exposing said first sensor to said gas during said second predetermined duration in step d); g) repeating the steps a)-f).

Claim 17

A method for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor in gas to be sampled, lowering electrical resistance across the semiconductor gas sensor upon exposure thereto, comprising the steps of: a) exposing a first gas detecting sensor of said semiconductor type to gas to be sampled to detect the oxygen depleting gas content continuously for a first predetermined duration and for another second predetermined duration; b) exposing a second gas detecting sensor of said semiconductor type to ambient air during said first predetermined duration in step a) and exposing said second gas detecting sensor to said gas during said first and second predetermined duration in step a); c) reading the electrical resistance across said first sensor to determine the content of said oxygen depleting gas during said first and second predetermined durations in step a); d) maintaining exposure of said second sensor to said gas for another first and second predetermined durations; e) reading the electrical resistance across said second sensor to determine the content of said oxygen depleting gas during said first and second predetermined durations in step d); f) exposing said first sensor to ambient air to remove any gas residue and to replenish said first sensor with oxygen depleted therefrom during said first predetermined duration in step d) and exposing said first sensor to said gas during said second predetermined duration in step d); g) repeating the steps a)-f).

Claim 20

A device for monitoring reducing gas in gas containing oxygen, comprising: a chamber having at least a pair of gas sensors of a semiconductor type which outputs a signal in response to exposure to reducing gas which depletes oxygen from said sensors; means in said chamber for permitting said gas containing oxygen to permeate through said gas chamber to expose said gas sensors thereto; a control means having a corresponding number of discrete, independent channels for connecting the outputs of said at least two sensors, converting the output signals from said first and second sensors to a readable format indicative of the content of said reducing gas and means for turning on and off said sensors, wherein said control means provides means for turning on and activating one of said at least two sensors for sampling the content of reducing gas while said other of said at least two sensors is turned off, for a first predetermined duration; means for turning on said other of said at least two sensors while said one sensor remains active for sampling after said first predetermined duration, for a second predetermined duration; means for activating said other sensor for sampling and turning off said one sensor after said second predetermined duration, for said first predetermined duration; and means for repeating said turning on and off, alternatively between said at least two sensors.

Claim 21

A device for monitoring reducing gas in gas containing oxygen, comprising: a chamber having at least a pair of gas sensors of a semiconductor type which outputs a signal in response to exposure to reducing gas which depletes oxygen from said sensors; means in said chamber for permitting said gas containing oxygen to permeate through said gas chamber to expose said gas sensors thereto; a control means having a corresponding number of discrete, independent channels for connecting the outputs of said at least two sensors, converting the output signals from said first and second sensors to a readable format indicative of the content of said reducing gas and means for turning on and off said sensors, wherein said control means provides means for turning on and activating one of said at least two sensors for sampling the content of reducing gas while said other of said at least two sensors is turned off, for a first predetermined duration; means for turning on said other of said at least two sensors while said one sensor remains active for sampling after said first predetermined duration, for a second predetermined duration; means for activating said other sensor for sampling and turning off said one sensor after said second predetermined duration, for said first predetermined duration; and means for repeating said turning on and off, alternatively between said at least two sensors.

Claim 23

A method for monitoring reducing gas in gas containing oxygen, comprising the steps of: a) providing at least a pair of sensors in a chamber which is porous as to permeate said oxygen containing gas and reducing gas; b) turning on one of said sensors continuously for a first predetermined duration and for a second predetermined duration; c) turning off the other of said sensors during said first predetermined duration and turning on said other of said sensors during said second predetermined duration in step b); d) reading signals output from said one sensor during said first and second predetermined durations in step b) to determine the content of said oxygen depleting gas; e) maintaining said other sensor on for another said first and second predetermined durations; f) reading signals output from said other sensor during said first and second predetermine durations in step e) to determine the content of said oxygen depleting gas; g) turning off said one sensor for said first predetermined duration and turning on said one sensor for said second predetermined duration, respectively during said first and second predetermined durations in step e) h) repeating the steps b)-g).

Claim 24

A method for monitoring reducing gas in gas containing oxygen, comprising the steps of: a) providing at least a pair of sensors in a chamber which is porous as to permeate said oxygen containing gas and reducing gas; b) turning on one of said sensors continuously for a first predetermined duration and for a second predetermined duration; c) turning off the other of said sensors during said first predetermined duration and turning on said other of said sensors during said second predetermined duration in step b); d) reading signals output from said one sensor during said first and second predetermined durations in step b) to determine the content of said oxygen depleting gas; e) maintaining said other sensor on for another said first and second predetermined durations; f) reading signals output from said other sensor during said first and second predetermine durations in step e) to determine the content of said oxygen depleting gas; g) turning off said one sensor for said first predetermined duration and turning on said one sensor for said second predetermined duration, respectively during said first and second predetermined durations in step e) h) repeating the steps b)-g).

Claim 26

A method for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor in gas to be sampled, lowering electrical resistance across the semiconductor gas sensor upon exposure thereto, comprising the steps of: a) providing first and second chambers, each containing a gas sensor of said semiconductor type; b) flowing gas to be sampled through said first chamber; c) flowing ambient air to said second chamber while said first chamber is flowing with gas; d) reading signals output from the gas sensor in said first chamber to determine the content of said oxygen depleting gas during steps b) and c); e) stopping the flow of ambient air through said second chamber and flowing the gas to be sampled therethrough instead; f) reading signals output from the sensor in said second chamber to determine the content of said oxygen depleting gas during step e); g) stopping the flow of the gas to be sampled to said second chamber and flowing instead with ambient air to remove any gas residue remaining therein and to replenish the oxygen depleted from the sensor in said first chamber during step e); h) repeating the steps b)-g).

Claim 27

A method for detecting and measuring gas content of the type which depletes oxygen component from a semiconductor type of gas sensor in gas to be sampled, lowering electrical resistance across the semiconductor gas sensor upon exposure thereto, comprising the steps of: a) providing first and second chambers, each containing a gas sensor of said semiconductor type; b) flowing gas to be sampled through said first chamber; c) flowing ambient air to said second chamber while said first chamber is flowing with gas; d) reading signals output from the gas sensor in said first chamber to determine the content of said oxygen depleting gas during steps b) and c); e) stopping the flow of ambient air through said second chamber and flowing the gas to be sampled therethrough instead; f) reading signals output from the sensor in said second chamber to determine the content of said oxygen depleting gas during step e); g) stopping the flow of the gas to be sampled to said second chamber and flowing instead with ambient air to remove any gas residue remaining therein and to replenish the oxygen depleted from the sensor in said first chamber during step e); h) repeating the steps b)-g).