Apparatus and method for calibrating a resistance thermometer and gas analyzer employing same

A gas composition analyzer comprising:

• a measurement cell having an interior adapted to receive a gas composition therein;
• a resistance thermometer thermally coupled to the interior of said measurement cell;
• an acoustic meter acoustically coupled to the interior of said cell for measuring a velocity of acoustic energy transmitted between components of said acoustic meter within said cell;
• a reference thermometer thermally coupled to the interior of said cell for generating, during a calibration procedure, a first reference temperature value of said gas composition at a first temperature;
• said acoustic meter being operable during said calibration procedure to obtain an acoustic velocity-related measurement in said gas composition in said cell at a second temperature for use in generating a second reference temperature value;
• and
• a calibration unit supplied with said first and second temperature values and said acoustic velocity-related measurement for determining a calibration relationship for the temperature thermometer from the first and second reference temperature values and from measurement values of the first and second temperatures supplied by the resistance thermometer.