Patent ID: 6586949
Filing Date: 2003-07-01
Classification: G01N

Abstract:
A sensor for testing a material sample, comprising:a housing having an electrically conductive shield; at least one chamber disposed within the housing for containing the material sample, the at least one chamber formed from an electrically non-conductive material and having at least one inlet and at least one outlet for allowing movement of the material sample through the at least one chamber; at least two electrical conductors corresponding to and disposed on opposite sides of the at least one chamber; a measurement circuit within the housing coupled to the at least two electrical conductors for producing a measurement signal having a frequency responsive to a capacitance defined by the at least two electrical conductors and the material sample between the at least two electrical conductors, the measurement circuit comprising: an oscillator circuit coupled to a first electrical conductor of the at least two electrical conductors; and a circuit ground potential coupled to a second electrical conductor of the at least two electrical conductors; and at least one of a first electrically-conductive extension and a second electrically-conductive extension, wherein the first electrically-conductive extension is positioned adjacent the at least one inlet, the first electrically-conductive extension having a first end for contacting the material sample in the at least one chamber, and a second end for connecting to a around potential, the first electrically-conductive extension conducting charges within the material sample to the ground potential; and wherein the second electrically-conductive extension is positioned adjacent the at least one outlet, the second electrically-conductive extension having a first end for contacting the material sample in the at least one chamber, and a second end for connecting to the ground potential, the second electrically-conductive extension conducting the charges within the material sample to the ground potential.