The Model 2000XTC Transmitter resets the standard for thermal conductivity detector based applications with the process control industry. As an intrinsically safe transmitter, packaged within a rugged, weatherproof housing, the 2000XTC is suitable for use in harsh, hazardous outdoor environments. Using a novel, solid-state thermal conductivity sensor, this cost effective transmitter can be configured to detect H2, He, N2 Ar, CO2 a number of other gases of or a number of other gases of interest in binary or multi-component interest in binary or multi-component sample gas mixtures.
The sensor structure consists of an integrated heater located within a thin electrical and thermal insulating membrane. Two thin film resistors are used for heating and measuring the temperature of the membrane. Two resistors are integrated on the silicon beside the membrane for the compensation off the ambient temperature changes.
The thermal conductivity sensor measures the concentration of a specific gas between a hot surface resistor and an ambient temperature reference resistor using the thermal conductivity coefficient of the gas itself. Gases which have a lower density than air (CH4) cause a decrease on the surface membrane temperature. On the other hand, gases with densities heavier than air (CO2) increase the temperature of the measuring resistor.