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Endothermic Atmosphere generators

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.

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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 usable 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.


Automatic Temperature Control
The temperature of the Thermal Dynamix Endothermic Generator retort chamber is controlled automatically. In our gas heated units admission of combustion air to the chamber is also closely regulated. These features, combined with the chamber being insulated with 10 inches of high performance ceramic insulation and a small retort diameter, keep heat transfer into the gas stream very fast and efficient and thermal losses very low, making the Thermal Dynamix endothermic Generator extremely efficient to operate. Heat is put into the chamber and process, not into the room.

Adjustable Feed Rates
Thermal Dynamix endo-generators are engineered with adjustable feed rates (turn-down capability) based on outlet pressure. This allows matching the supply of endo-gas to the demand thereby maximizing economy of operation. Our standard configuration assumes an output gas pressure of 1.5 – 3.0 psig. However, the system can be configured for output gas pressure of up to 20 psig if desired.

Available Sizes
If your requirement is for between 250 SCFH (standard cubic feet per hour) and 6,000 SCFH we have a standard endothermic generator to meet your needs. Our standard configurations are sized (in SCFH) as follows: 250, 500, 1000, 2000, 3000, 4000, 6000.

If your need is for greater capacity Thermal Dynamix can design and build a generator tailored specifically to your unique situation.

Economical Operation
Thermal Dynamix endothermic Generator is available in either gas-fired or electrically heated configuration. This allows selection of the most economical source of energy for operation. Each generator is a package unit, completely self contained and requiring only three connections; an electrical, one for fuel gas feedstock and the process gas output connection.

Our generator is designed for natural convection cooling. There are no cooling fans or blowers to maintain and, with no power required for cooling, operating costs are absolutely minimal. Our retorts, the smallest diameter in the industry, provide faster and more efficient heat transfer into the process gas stream. This enables a lower chamber temperature resulting in more economical operation and longer retort life.

Periodic Maintenance
As with all equipment, periodic maintenance will be required. Ours happens to require less than most of our competitors. We’ve designed the Thermal Dynamix endo-generator to be maintenance friendly. It is well enough instrumented so that, in many cases, you can tell where the problem is. When the time comes to replace a retort or heating element you can easily get to the part. You don’t have to dismantle the whole machine. Both heating elements and retort are top mounted and each may be removed from the generator without disturbing the other.


Available Models:


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500 SCFH

1500 SCFH endothermic generator

1500 SCFH

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2000 SCFH

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