Patent ID: 6222372
Filing Date: 2001-04-24
Classification: G01N

Abstract:
A gas sensor measuring a given component content in a gas comprising:a housing;a sensing unit having a given length, disposed in said housing, said sensing unit having defined in one end portion thereof a reference gas chamber to be filled with a reference gas and also having installed in the one end portion a measuring electrode to be exposed to the gas to be measured and a reference electrode to be exposed to the reference gas in the reference gas chamber, the measuring electrode and the reference electrode being disposed adjacent to each other through a solid electrolyte body and providing through signal pickup leads sensor signals which are used in determining the given component content in the gas;a first metallic cover installed on said housing to cover the other end portion of said sensing unit;a second metallic cover installed on a periphery of said first metallic cover through a water-repellent filter, said second metallic cover being crimped to be joined to said first metallic cover through the water-repellent filter;a first vent formed in said first metallic cover;a second vent formed in said second metallic cover which communicates with said first vent through the water-repellent filter to introduce the reference gas into the reference gas chamber through a reference gas passage extending from said second vent to the reference gas chamber; andan insulator mounted within said first metallic cover, having formed therein holes through which the signal pickup leads pass, said insulator having an outer wall different in geometry from an inner wall of said first metallic cover to define a portion of the reference gas passage between the outer wall of said insulator and the inner wall of said first metallic cover,wherein the different in geometry of the outer wall of said insulator from the inner wall of said first metallic cover provides better flow of the reference gas into the reference gas chamber.