Autocalibrating dual sensor non-contact temperature measuring device

Apparatus for non-contact measurement of the temperature of a moving filament that is traveling along a linear path comprising:

• first and second thermally conductive reference bodies;
• means for maintaining said first and second reference bodies at different temperatures;
• first and second heat flow sensors carried by said first reference body so that said heat flow sensors are positioned on opposite sides of said filament, wherein said first and second heat flow sensors are substantially matched in sensitivity and are connected in series, wherein said first and second heat flow sensors are reactive to heat flow to generate a first heat flow output signal that is proportional to the heat flow rate between the filament and the first reference body, and wherein each heat flow sensor has a plurality of heat flow sensitive elements that are linearly positioned so that the first heat flow sensor has a first row of sensitive elements that is not parallel to the path of said filament and the second heat flow sensor has a second row of sensitive elements that is not parallel to the path of said filament;
• third and fourth heat flow sensors carried by said second reference body so that said heat flow sensors are positioned on opposite sides of said filament, wherein said third and fourth heat flow sensors are substantially matched in sensitivity and are connected in series, wherein said third and fourth heat flow sensors are reactive to heat flow to generate a second heat flow output signal that is proportional to the heat flow rate between the filament and the second reference body, wherein the third and fourth heat flow sensors have a plurality of heat flow sensitive elements that are linearly positioned so that the third heat flow sensor has a third row of sensitive elements that is not parallel to the path of said filament and the fourth heat flow sensor has a fourth row of sensitive elements that is not parallel to the path of said filament;
• first and second temperature sensors carried by said first and second reference bodies, respectively, wherein said first temperature sensor is in thermal communication with and adapted to generate a first temperature output signal that is proportional to the temperature of the first reference body, and wherein said second temperature sensor is in thermal communication with and adapted to generate a second temperature output signal that is proportional to the temperature of the second reference body;
• and
• means responsive to said first and second heat flow output signals and said first and second temperature output signals for calculating the temperature of said filament.