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The thermal conductivity detector (TCD), also known as a katharometer, is a bulk property detector and a chemical specific detector commonly used in gas chromatography. [1] This detector senses changes in the thermal conductivity of the column eluent and compares it to a reference flow of carrier gas. Since most compounds have a thermal ...
A hydrogen sensor is a gas detector that detects the presence of hydrogen. They contain micro-fabricated point-contact hydrogen sensors and are used to locate hydrogen leaks. They are considered low-cost, compact, durable, and easy to maintain as compared to conventional gas detecting instruments.
A pellistor is a solid-state device [1] used to detect gases which are either combustible or which have a significant difference in thermal conductivity to that of air. The word "pellistor" is a combination of pellet and resistor .
Pirani was aware of the gas thermal conductivity investigations of Kundt and Warburg [4] (1875) published thirty years earlier and the work of Marian Smoluchowski [5] (1898). In 1906 he described his "directly indicating vacuum gauge" that used a heated wire to measure vacuum by monitoring the heat transfer from the wire by the vacuum environment.
The transient hot wire method has advantage over the other thermal conductivity methods, since there is a fully developed theory and there is no calibration or single-point calibration. Furthermore, because of the very small measuring time (1 s) there is no convection present in the measurements and only the thermal conductivity of the fluid is ...
Detection of gas concentrations usually involves the use of a flame ionization detector (FID) and a thermal conductivity detector (TCD). Most systems also employ a methanizer, which converts any carbon monoxide and carbon dioxide present into methane so that it can be burned and detected on the FID, a very sensitive sensor. [5]
The range of thermophysical properties can be covered by different forms of the technique, with the exception that the recommended thermal conductivity range where the highest precision can be attained is 0.01 to 150 W/m•K for the linear source freestanding sensor and 500 to 8000 J/m2•K•s0.5 for the planar source freestanding sensor.
Hydrogen-rich fuel A fuel that contains a significant amount of hydrogen, such as gasoline, diesel fuel, methanol (CH3OH), ethanol (CH3CH2OH), natural gas, and coal. Hydrogen sulfide sensor A hydrogen sulfide sensor or H 2 S sensor is a gas sensor for the measurement of hydrogen sulfide in a gas stream.