Patent ID: 6275048
Filing Date: 2001-08-14
Classification: G01F

Abstract:
A capacitive sensor for measuring a characteristic of a liquid or gas, said capacitive sensor comprising at least two carrier boards carrying printed circuit elements, at least one spacer plate between said at least two carrier boards for spacing said carrier boards from each other, a hollow space in said at least one spacer plate, said printed circuit elements comprising metal coatings on inner board surfaces facing said hollow space, said metal coatings forming capacitor plates, at least one first port positioned in said sensor for said liquid or gas to enter into said hollow space inside said sensor, at least one second port positioned in said sensor spaced from said first port for permitting said liquid or gas to exit from said hollow space for pressure equalization in said hollow space relative to pressure outside said hollow space whereby, in operation, said liquid or gas forms a dielectric between said capacitor plates, and wherein said printed circuit elements further comprise conductor leads connected to said capacitor plates for retrieving sensed signals from said capacitor plates.