Disposable liquid level sensor having a virtual ring

An apparatus for determining the level of a conductive liquid held within a bottle that is inserted into an appliance, said apparatus comprising:

• a holder having a piercing element for punching a hole in the bottle in order to release the contents of the bottle;
• electrical connection buttons attached to said holder wherein said electrical connection buttons connect said apparatus to the control circuitry of said appliance;
• a sensor having electrical connection buttons that mate with the electrical connection buttons on said holder;
• wherein said sensor comprises:
• an insulated probe having an attachment end and a sensor end, wherein the attachment end of said insulated probe is connected to said holder such that the probe end is able to contact the conductive liquid held therein;
• a conducting sensor tip having a voltage and disposed at the probe end of said insulated probe;
• a ground connection having an electrical polarity, said ground connection being in contact with the conductive liquid;
• an exposed tip of a bias wire which exits said insulated probe positioned between said attachment end and said sensor end such that a bias voltage at said exposed tip provides a virtual bias voltage circumferential ring around said insulated probe immediately adjacent to said exposed tip;
• wherein the bias voltage of the virtual bias voltage circumferential ring has a polarity opposite of said ground connection wherein the bias voltage corresponds to the voltage of said conducting sensor tip;
• wherein once the liquid is in contact with said conducting sensor tip at a predetermined level, a circuit is completed to said ground connection which indicates a “full” condition and wherein if the liquid is not in contact with said conducting sensor tip at the predetermined level a “not full” condition is indicated, and wherein the bias voltage of said virtual circumferential ring prevents a false indication of a “full” condition by preventing the completion of circuit from said conducting sensor tip to said ground connection via residue on the container walls and said insulated probe even when the liquid is not in contact with said conducting sensor tip.