Patent ID: 6634229
Filing Date: 2003-10-21
Classification: G01F

Abstract:
A fluid level sensing system comprising:a container having lower and upper portions; a resistive element disposed in the container, the resistive element having an upper end portion disposed in the upper portion of the container and a lower end portion disposed in the lower portion of the container, a resistance of the resistive element increases from the upper portion of the container toward the lower portion of the container, the resistive element is a semi-conductive film strip deposited onto a non-conductive substrate, the semi-conductive film strip comprises a plurality of discrete strip portions each having a corresponding width dimension such that an output signal across the film strip varies substantially linearly with changing fluid level in the container, a plurality of electrodes disposed thereon in spaced apart relation between the upper and lower end portions of the resistive element, each of the plurality of electrodes is coupled to a corresponding discrete portion of the resistive element; an at least partially conductive strip disposed in the container generally parallel to the resistive element, the at least partially conductive strip and the resistive element having approximately the same length and positioned at approximately the same level as the resistive element in the container, a series resistor having a first end portion coupled to the upper end portion of the resistive element; an input signal source coupled to a second end portion of the series resistor.