Patent ID: 6045673
Filing Date: 2000-04-04
Classification: G01N

Abstract:
A gas sensor for determining an amount of a specified component in a measurement gas by reducing or decomposing said component having bound oxygen in said measurement gas and measuring an amount of oxygen produced during said reduction or decomposition, said gas sensor comprising:first and second substrates comprising solid electrolytes stacked through a spacer thereby defining at least two internal spaces between said electrolytes;a first diffusion rate-determining section for introducing said measurement gas under a predetermined diffusion resistance;a first internal space for making communication with an atmosphere of said measurement gas via said first diffusion rate-determining section;a first electrochemical pumping cell comprising said first solid electrolyte for constructing said first internal space and a pair of first pumping electrodes provided in contact therewith;a first electrochemical sensor cell comprising said second solid electrolyte for constructing said first internal space and a pair of first measuring electrodes provided in contact therewith;a second diffusion rate-determining section for introducing, under a predetermined diffusion resistance, said gas adjusted to have a predetermined value of oxygen concentration in said first internal space;a second internal space for making communication with said atmosphere of said measurement gas via said second diffusion rate-determining section;a second electrochemical pumping cell comprising said first solid electrolyte for constructing said second internal space and a pair of second pumping electrodes provided in contact therewith;a second electrochemical sensor cell comprising said second solid electrolyte for constructing said second internal space and a pair of second measuring electrodes with one of said second measuring electrodes provided in contact therewith and with another of said second measuring electrodes in contact with said first solid electrolyte;a third diffusion rate-determining section for introducing, under a predetermined diffusion resistance, said gas adjusted to have a predetermined value of oxygen concentration in said second internal space;a third electrochemical pumping cell having two pumping electrodes for pumping out oxygen produced by reduction or decomposition of said component having bound oxygen in said measurement gas introduced via said third diffusion rate-determining section; anda current-detecting means for detecting a pumping current which is allowed to flow in accordance with operation of said third electrochemical pumping cell, whereinsaid another of said second measuring electrodes and one of said third electrochemical pumping electrodes are provided in said second internal space, and are arranged opposingly to one another across said second internal space.