Gas sensor

Abstract

A gas sensor for the detection of gases comprises a housing and an active element disposed within the housing. The active element is surrounded by a porous insulating material having a bulk density no greater than 0.15 g/cc. Another gas sensor comprises an active element surrounded by a porous insulating material having a surface area no greater than approximately 200 m 2 /cc. Another gas sensor comprises a copper compound positioned so that gas contacts the copper compound before contacting the active element. Another gas sensor comprises an active element surrounded by a porous material having an average pore size of at least approximately 100 Å.

1 - 27 . (canceled)  
     
     
         28 . A gas sensor for the detection of combustible gases comprising, a housing, an active element disposed within a first chamber in the housing, a copper compound that acts as a scavenger disposed in the sensor so that gas contacts the copper compound before contacting the active element.  
     
     
         29 . The gas sensor of  claim 28  wherein the copper compound is copper sulfate.  
     
     
         30 . The gas sensor of  claim 28  wherein copper compound is supported upon a porous material surrounding the active element.  
     
     
         31 . The gas sensor of  claim 28  wherein the copper compound is positioned outside the housing.  
     
     
         32 . A gas sensor for the detection of an analyte gas comprising, a housing and a heating element disposed within a first chamber in the housing, the heating element being surrounded by a porous material that supports a catalyst and a copper-containing compound, the copper-containing compound acting as a poison scavenger.  
     
     
         33 . The gas sensor of  claim 32  wherein the porous material has a bulk density no greater than approximately 0.3 g/cc.  
     
     
         34 . The gas sensor of  claim 32  wherein the porous material has a surface area of less than approximately 200 m 2 /cc.  
     
     
         35 . The gas sensor of  claim 32  wherein the porous material has an average pore size of at least approximately 100 Å.  
     
     
         36 . The gas sensor of  claim 32  wherein the copper compound is copper sulfate.  
     
     
         37 . The gas sensor of  claim 32  wherein the porous material that supports the copper-containing compound surrounds the porous material that supports the catalyst.  
     
     
         38 . A gas sensor for the detection of combustible gases comprising: a housing, an active element disposed within a first chamber in the housing and a copper-containing compound supported upon a porous material surrounding the active element to act as a scavenger for poisoning compounds.  
     
     
         39 . The gas sensor of  claim 38  wherein the copper compound is copper sulfate.  
     
     
         40 . The gas sensor of  claim 38  wherein the porous material has a bulk density no greater than approximately 0.3 g/cc.  
     
     
         41 . The gas sensor of  claim 38  wherein the porous material has a surface area of less than approximately 200 m 2 /cc.  
     
     
         42 . The gas sensor of  claim 38  wherein the porous material has an average pore size of at least approximately 100 Å.  
     
     
         43 . The gas sensor of  claim 38  wherein the porous material is a powder.  
     
     
         44 . The gas sensor of  claim 30  wherein the porous material is a powder.  
     
     
         45 . The gas sensor of  claim 30  wherein the porous material has a bulk density no greater than approximately 0.3 g/cc.  
     
     
         46 . The gas sensor of  claim 30  wherein the porous material has a surface area of less than approximately 200 m 2 /cc.  
     
     
         47 . The gas sensor of  claim 30  wherein the porous material has an average pore size of at least approximately 100 Å.