Using Controlled Atmosphere Natural Gas Furnaces
Natural gas furnaces use direct fuel combustion to heat a sample within the equipment’s internal chamber. Electrical heaters with ceramic fiber and metallic wire thermal elements have found more common application than natural gas furnaces in recent years, with advances in low mass vacuum forming of ceramic insulation providing improved thermodynamic capacities. However, certain firing applications require natural gas heating for increased heating speeds, improved temperature uniformity, or distinct chamber-atmosphere conditions.
Controlled atmosphere natural gas furnaces enable manufacturers to thermally treat products or materials to refractory temperatures with exceptional selection of the internal atmospheric composition. This article will outline the capacities of one of the exceptional natural gas firing furnaces available from Thermcraft in more detail:
At Thermcraft, we have manufactured a robust natural gas furnace that meets military specifications, with a high temperature capacity of up to 1371°C (2500°F) and a temperature uniformity of within +/-25°F. This immense machinery is constructed from a continuously welded shell of plate steel and structural joists with high-performance ceramic fiber blanket insulation installed in the walls and roof of the furnace.
Silicon carbide rods are used to heat the internal furnace, which is lined with refractory plates that are suspended above the high-thermal heating elements. This arrangement enables the sample or product to be safely protected from direct contact with the heating elements, which feature a power density of less than 50 Watts per square inch (W/in2). Natural gas or propane is burned by automatic pilots that create an internal flame curtain to protect the controlled atmosphere of the furnace chamber.
Nitrogen flowmeters control gas flows throughout the heating chamber, with flame supervision interlocks preventing the introduction of combustible gas into the chamber. Endothermic, exothermic, and enriched atmospheres can be created within the natural gas furnace, with gaseous compositions including nitrogen, argon, or air. These atmospheric controls are used to monitor the temperature, power, and pilots for potential fluctuations or emergencies. These readings can be used to automatically shut-down heat treatment processes with a rapid nitrogen purge in the event of malfunction or unsustainable temperature values.
This rugged natural gas furnace can be used for a range of applications, with additional instrumentation available to suit distinct curing applications. These include a percentage carbon indicator for process monitoring, automatic carbon control with natural gas enrichment for improved process automation, and internal alloy rollers for heat treating larger component batches at temperatures of up to 1093°C (2000°F).
Natural Gas Furnaces from Thermcraft
Thermcraft is a leading developer and supplier of heat treatment equipment for an array of industrial applications. Our equipment is routinely used for thermal processing in the military, pharmaceutical, automotive sectors, and more. We can construct custom furnaces that are distinct to your applications, using electric heating or natural gas firing methodologies.