Apparatus for and method of calibrating a resistance thermometer and a gas analyser employing the same

摘要

A calibration apparatus for a resistance thermometer (6,10) comprises a reference thermometer (12) locatable in thermal contact with a gas composition to generate during a calibration period a first reference temperature value for the gas composition at a first temperature and an acoustic meter (16,18,20) locatable in acoustic contact with the gas composition and adapted to make during the calibration period an acoustic velocity related measurement for use in generating a second reference temperature value for the gas composition at a second temperature. A calibration unit (24) is adapted to coordinate the first and second reference temperature values with first and second measurement temperature values provided by the resistance thermometer (6,10) at the first and the second temperatures respectively and to establish a calibration relationship therefrom. <IMAGE>