Surface Combustion, Inc.

Garry W Barbee

Ralph Paul Poor

Michael J Huber

Stephen Harry Verhoff

James Edward Brug

William J Bernard

John W Gottschalk

Jerry P Jason

A system for treating metallic articles in an atmospheric furnace while injecting at least one fluid material within the furnace and/or in a catalyst bed connected to the furnace.

Surface treatment of metallic articles in an atmospheric furnace

Vacuum carburizing of ferrous workpieces is performed at low pressure in a vacuum furnace using an unsaturated aromatic such as benzene as the carburizing medium. The unsaturated aromatic is gas phase hydrogenated into a napthenes, such as cyclohexane, which is metered into the furnace chamber proper and functions as the carburizing gas. The furnace is constructed to be generally transparent to the napthenes so that cracking tends to occur at the workpiece which functions as a catalyst to minimize carbon deposits. The unsaturated aromatic is supplied in liquid form to fuel injectors which inject the liquid aromatic as a vapor at duty cycles and firing orders to produce a uniform dispersion of the hydrocarbon gas about the work resulting in uniform carburizing of the workpieces. An in-situ methane infrared sensor controls the process. Excess hydrogen beyond what is required to hydrogenate the aromatic is added to the furnace chamber to either assure full carbon potential and produce methane or to perform variable carburizing. Hydrogenation occurs in a hydrogenation coil in fluid communication with the furnace chamber with temperature for the reaction set by the position of the hydrogenation coil in the furnace insulation.

Vacuum carburizing with unsaturated aromatic hydrocarbons

Vacuum carburizing of ferrous workpieces is performed at low pressure in a vacuum furnace using a napthene hydrocarbon as the carburizing medium. The furnace is constructed to be generally transparent to the napthene so that cracking tends to occur at the workpiece which functions as a catalyst to minimize carbon deposits. The napthene is supplied in liquid form to fuel injectors which inject the liquid napthene as a vapor at duty cycles and firing orders to produce a uniform dispersion of the hydrocarbon gas about the work resulting in uniform carburizing of the workpieces. An in-situ methane infrared sensor controls the process. Hydrogen is added to the napthene to either assure full carbon potential and produce methane or to perform variable carburizing.

Vacuum carburizing with napthene hydrocarbons

A drying system is disclosed for drying wet gases, typically produced by a gas generator to dew points less than 32.degree. F. The system uses a refrigeration cycle having a single compressor to dry the wet gas in a first evaporator while simultaneously defrosting the ice buildup on a second evaporator. The cycle then switches from the first evaporator to the second evaporator after the second evaporator is defrosted. The switching is preceded by a changeover phase in which cooled refrigerant is pulsed to the defrosted evaporator and both evaporators go on line for a short time before the system phase change occurs thus assuring control of the dried gas temperature while avoiding shock to the refrigeration system.

Low dew point gas generator cooling system

A system for use in sensing the oxygen content of an industrial furnace gas typically containing hydrocarbons or hydrogen is disclosed. The system utilizes a conventional automotive EGR oxygen sensor probe positioned in an especially configured housing employing downstream flow regulating means in combination with an orificing plate in the housing to provide uniform distribution of the endothermic gas at a low temperature about the sensor to insure accurate sensor readings with minimal carbon deposition. The electrical contacts at the oxygen sensor's inner and outer electrolyte surfaces are periodically switched to an electrical power supply to cause current to flow through and heat the electrolyte to elevated temperatures while air is flowed over the electrolyte's surfaces to achieve burn out of any carbon deposits and restore the life of the oxygen sensor probe. In addition, a portion of the sensor is thermally shielded to maintain somewhat equal reference air and furnace gas temperatures to produce consistent and reliable output signals from the oxygen sensor probe.

Gas analysis system for furnaces and the like

A system for use in sensing the oxygen content of an industrial furnace gas typically containing hydrocarbons or hydrogen is disclosed. The system utilizes a conventional automotive EGR oxygen sensor probe positioned in an especially configured housing employing downstream flow regulating means in combination with an orificing plate in the housing to provide uniform distribution of the endothermic gas at a low temperature about the sensor to insure accurate sensor readings with minimal carbon deposition. The electrical contacts at the oxygen sensor's inner and outer electrolyte surfaces are periodically switched to an electrical power supply to cause current to flow through and heat the electrolyte to elevated temperatures while air is flowed over the electrolyte's surfaces to achieve burn out of any carbon deposits and restore the life of the oxygen sensor probe. In addition, a portion of the sensor is thermally shielded to maintain somewhat equal reference air and furnace gas temperatures to produce consistant and reliable output signals from the oxygen sensor probe.

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Rossford, OH, United States of America

Garry W Barbee