5.0     TECHNICAL INFORMATION

The Nitriding Sample Cell is a device that produces an output that is a function of the thermal conductivity of the gas surrounding its sensor. Gases differ in their thermal conductivity and the thermal conductivity of a mixture is approximately the mathematical average of the thermal conductivity and concentration of each component. Because thermal conductivity is a bulk physical property of the gas its measurement is not specific for any component. The Model 9210 is programmed in such a way that it assumes the components are always the same species, e.g. oxygen, nitrogen and carbon dioxide. If a gas mixture containing other components is introduced into the sample cell it will not produce the correct readings.