Method and apparatus for modulating a gas sample for a calorimetric gas sensor

摘要

A method and apparatus is provided for modulating flux of combustibles reacting with oxygen impinging on a calorimetric gas sensor. The method includes the steps of enclosing a sensing element (16) and a reference element of a calorimetric gas sensor (11) with an apparatus having at least one aperture (30) to allow combustibles to enter and impinge on the sensing element and reference element, periodically restricting the aperture (30) of the apparatus to modulate the flux of combustibles entering at a predetermined frequency to produce an AC output signal from the calorimetric gas sensor (11), and measuring the sensor output at the frequency at which the aperture (30) is restricted. <IMAGE>