Patent ID: 7413641

Claim:
A gas sensor which works to measure a given component content in a gas and has a length with a top and a base end opposed to the top end, comprising: a cylindrical housing; a sensing element disposed in said housing, said sensing element having a length which includes a top portion facing the top end of the gas sensor, sensitive to the gas and a base portion facing the base end of the gas sensor; and a cylindrical cover assembly installed on said housing to cover the top portion of said sensing element, said cover assembly having a length with a top end facing the top end of the gas sensor and a base end facing the base end of the gas sensor, said cover assembly including a first cover and a second cover retained outside the first cover, the first and second covers having side walls, respectively, the side wall of the second cover having formed therein a plurality of gas holes through which the gas flows inside or outside said cover assembly, at least one of the gas holes partially facing the side wall of the first cover in a lateral direction perpendicular to a longitudinal direction of said cover assembly, the at least one of the gas holes having a first portion of a perimeter closest to the top end of said cover assembly and a second portion of the perimeter closest to the base end of said cover assembly, the first cover having a top end which faces the top end of said cover assembly and is located within a range defined between the first and second portions of the perimeter of the at least one of the gas holes in the longitudinal direction of said cover assembly, wherein the side wall of the first cover has formed therein a plurality of gas holes through which the gas flows inside or outside the first cover, all side wall gas holes of the first cover being located closer to the base end of said cover assembly than all gas holes of the second cover.