Patent ID: 8620603

Claim:
A tank comprising: a wall having an inner surface, wherein an insulating layer is disposed on a first portion of the inner surface; a vane that is disposed within the tank and that is configured to facilitate extraction of a fluid from the tank, wherein the vane comprises an electrically conductive material; a first connector to electrically couple a portion of the wall to a capacitance sensing device; and a second connector to electrically couple a portion of the vane to the capacitance sensing device, wherein, when the capacitance sensing device is coupled to the first connector and is coupled to the second connector, the capacitance sensing device is operable to measure a capacitance between the portion of the vane and the portion of the wall, wherein the capacitance sensing device is coupled to a controller, the controller operable to receive information representative of the capacitance between the portion of the vane and the portion of the wall and to apply a function to the information representative of the capacitance between the portion of the vane and the portion of the wall to determine an amount of the fluid remaining in the tank, and wherein the function is associated with a relationship between the amount of the fluid that is contained in the tank and the capacitance.