Patent ID: 6287439
Filing Date: 2001-09-11
Classification: G01N

Abstract:
A gas sensor comprising:a main pumping means for pumping-processing oxygen contained in a measurement gas introduced from an external space into a processing space defined by a first chamber formed by solid electrolytes contacting with said external space so that a partial pressure of oxygen in said processing space is controlled to have a predetermined value at which a predetermined gas component contained in said measurement gas is not decomposable;a measuring pumping means for decomposing a measurement gas component contained in said measurement gas introduced from said first chamber into another processing space defined by a second chamber, after being pumping-processed by said main pumping means, by means of catalytic action and/or electrolysis so that oxygen produced by said decomposition is subjected to a pumping process; anda heater for heating at least said main pumping means and said measuring pumping means to predetermined respective temperatures, said heater having a serpentine pattern extending across said first and second chambers, said pattern having a pitch which is wider at one end, across a region adjacent said second chamber, than at another end thereof, so that the temperature of said measuring pumping means is lower than the temperature of said main pumping means:wherein:said measurement gas component contained in said measurement gas is measured on the basis of a pumping current allowed to flow through said measuring pumping means in accordance with said pumping process effected by said measuring pumping means; andsaid measuring pumping means has a resistivity of electronic conduction of not less than 1 M.OMEGA. after conversion into a resistance value and not more than about 20 M.OMEGA..