Patent ID: 8313236
Filing Date: 2012-11-20
Classification: G01N

Abstract:
1. A thermal conductivity detector, comprising: a structure defining a cavity, the structure principally comprising a material having a first coefficient of thermal expansion; a sensing element for sensing a thermal conductivity of a gas flowing within the cavity, the sensing element having a second coefficient of thermal expansion different from the first coefficient of thermal expansion, the sensing element being disposed at least in part within the cavity; a first insulating material substantially covering the sensing element, the first insulating material having a third coefficient of thermal expansion different from the first and second thermal coefficients of expansion; and a second insulating material substantially covering the first insulating material, the second insulating material having a fourth coefficient of thermal expansion different from the first and second thermal coefficients of expansion, wherein one of the first and second insulating materials has an intrinsic compressive stress, and the other of the first and second insulating materials has an intrinsic tensile stress.