Method and apparatus for detecting the internal liquid level in a vessel

A method for detecting the level of a liquid in a vessel, comprising the steps of:

• actuating a heater mounted on a thermally conductive substrate mounted within the vessel, said actuation adding heat to the surface of the substrate thermally coupled to the interior of the vessel;
• detecting by a sensor the temperature in the vessel after said addition of heat, the sensor being mounted on the substrate within the vessel in proximity to the heater, the sensor generating an electrical signal indicative of the temperature, said electrical signal defining a temperature signal;
• transmitting the temperature signal from the sensor to a processor wherein the temperature signal received by the processor after actuation of the heater is defined by a subsequent signal,
• detecting by the sensor the temperature in the vessel before said addition of heat, the sensor being in proximity to the heater, the sensor generating an electrical signal defined by an initial temperature signal indicative of the temperature before said addition of heat, and
• transmitting the initial temperature signal from the sensor to the processor, said reference temperature in said step of operating the processor being defined by the initial temperature signal;
• and
• operating the processor to
• calculate the difference between the temperature signal and a reference temperature,
• generate an electrical signal defining a high signal indicating that the elevation of the upper surface of the liquid is above the sensor if the magnitude of the difference is less than a standard, and transmit the high signal to an interface electrically connected to the processor,
• generate an electrical signal defining a low signal indicating that the elevation of the liquid upper surface is below the sensor if the magnitude of the difference is greater than the standard, and transmit the low signal to the interface;
• communicating by the interface to the user the relative elevation of the liquid upper surface as either above or below the sensor based on receipt of either the high or low signal.

A system for detecting the level of a liquid in a vessel, comprising:

• a detector assembly including
• a thermally conductive substrate;
• means for supporting said substrate within the vessel,
• a heater mounted on said substrate within the vessel such that said heater is thermally coupled to the interior of the vessel, said heater being able to be actuated to add heat to the surface of the substrate thermally coupled to the interior of the vessel, and
• a sensor mounted on said substrate within the vessel in proximity to said heater, said sensor being thermally coupled to the interior of the vessel to detect the temperature therein in proximity to said sensor, said sensor being able to be actuated to generate an electrical signal defining a temperature signal indicative of said detected temperature;
• a processor electrically connected to said sensor for receiving said temperature signal after actuation of said heater, said processor being programmed to calculate a temperature index proportional to said temperature signal, said processor being further programmed to compare said temperature index to a reference thereby to generate an electrical signal defining an elevation signal indicative of the elevation of the upper surface of the liquid being either above or below said sensor;
• an interface electrically connected to said processor for receiving said elevation signal for use as the basis for communicating to the user the relative elevation of the liquid upper surface as either above or below said sensor;
• a power supply electrically connected to said heater, sensor, processor, and interface;
• and
• wherein said processor also receives said temperature signal prior to the actuation of said heater, said processor being programmed to calculate a temperature index proportional to both said temperature signals prior to and after actuation of said heater.