Thermal transpiration correction in capacitance manometers

Capacitance manometers with sensors maintained at temperatures above ambient show a non-linearity in their pressure response. It is shown that the magnitude of this effect is consistent with the thermal transpiration effect calculated from simple kinetic theory. In addition, good agreement is found with the empirical model of Takaishi and Sensui5. This model provides a simple method of calculating the response of a capacitance manometer, for a given gas, from a previous calibration with any gas.