L&L Special Furnace Co. Inc. shipped a floor-standing, high-temperature box furnace to a global supplier of piezo ceramics used in the military, aerospace and medical industries. The furnace, which has an effective work zone measuring 18 inches wide x 18 inches high x 36 inches deep, has a double-pivot horizontal door. It is used for processing glass products to 2500°F (1371°C). This process causes lead to outgas. As a result, the furnace interior is constructed of high-alumina refractory with less silica than normal linings, which helps delay the corrosive reaction between the silica present in the refractory and the lead outgassing at elevated temperatures.

There is also a removable layer of recrystallized alumina fiberboard in the hot zone. This sacrificial high-alumina board can be removed and easily replaced, which helps maintain the furnace chamber’s integrity.

The furnace is powered by high-density, silicon-carbide elements located above and below the furnace hearth. A tap transformer with multiple taps was included to adjust the primary element voltage as needed as the heating elements change in resistance. An SCR power control with soft start regulates the output voltage to the elements. The furnace, which also includes a free-standing NEMA12 control panel with fused disconnect and Type R thermocouple for instrumentation, was constructed to NFPA 86 guidelines for safety.