Lucifer Furnaces built and shipped a dual-chamber furnace to a company in the Midwest that will use it to heat treat small tool-steel parts in-house in a timely manner. The Red Devil furnace has working dimensions of 12 inches high x 14 inches wide x 18 inches long in both upper and lower chambers. The upper hardening chamber is rated up to 2200°F (1205°C), while the lower convection oven tempers up to 1200°F (650°C).  This unit was customized with a programmable controller with an over-temperature safety system for the upper chamber and a seven-day timer with alarm for audible event notification.

Both chambers are lined with a multilayered 4.5-inch combination of lightweight firebrick hot-face insulation and mineral-wool backup insulation for energy-efficient operation. The firebrick is precision dry fit inside the chamber with staggered seams for reduced heat loss while allowing for thermal expansion. Heating elements are coiled with heavy-gauge, low-watt-density wire mounted in easy-to-replace side-wall panels.

The lower chamber has a rear-mounted fan for uniform heat circulation. Ceramic hearth plates in both chambers support the workload and protect floor brick and can be replaced without removing heating elements.