Endothermic gas generators are used to produce atmospheres necessary for the scale free hardening, carburizing and carbon restoration of steel as well as the cover gas for the annealing of copper and for the silver brazing and sintering processes. A typical use would be in the case hardening of steel gears where the carbon content of the steel has to be tightly controlled. Endothermic generators built by Thermal Dynamix are compact, air cooled, efficient and reliable producers of these atmospheres.
An endothermic generator is comprised of a heavily insulated, heated chamber; a nickel catalyst filled retort; a feedstock gas metering system, a chamber heating system and an output gas cooling system.
A precisely metered mixture of feedstock gas (usually natural gas, propane or butane) and air is introduced into the catalyst filled retort where it is heated to approximately 1850 F. The mixture reacts with the catalyst which prompts the conversion of the feedstock gas and air to a process gas mixture of approximately 40% nitrogen, 38% hydrogen, 20% carbon monoxide and 2% carbon dioxide and methane. The input air/gas ratio can be adjusted, within limits from lean (more air) to rich (more feedstock), to vary the carbon potential or dew point making the output atmosphere useable for a wide range of heat treating requirements. Upon completion of the reaction process the endo-gas is cooled to about 120 F and sent to its intended use. Upon occasion the gas is dried to a lower dew point and once and a while it is compressed but most often it is used as it is produced without further finishing.