Patent ID: 7055369

Claim:
A gas detector used in the atmosphere which includes a housing having an intake to let in the gas to be detected and in which the gas let in through the intake is detected by a gas sensor, wherein: said intake is formed upward in said housing, a porous film having waterrepellant and oil-repellant properties is stretched horizontally at an upper end of the intake, a protective cap is provided on said housing, which has a protective plate covering over a surface of said porous film in a state that the protective plate is separated upward from the surface of the porous film and leg portions suspending from an outer peripheral surface of the protective plate, and a gas passage is defined by said housing and said protective cap, which is open so that gas enters at extreme ends of said leg portions which are not circumferentially sealed to the housing and is bent at an upper portion in a horizontal direction, with a space defined between the porous film and said protective plate being secured to let the external atmosphere flow in over the porous film through said gas passage.