L&L Special Furnace Co. shipped two high-uniformity bell-type furnaces for use in the manufacturing of photovoltaic solar panels. The primary purpose of the furnaces is to evenly heat pure silicon bars to temperatures up to 1200°C(2192°F) and hold for two to three hours. The L&L model WQ11 furnace has a work envelope of 17 inches wide x 126 inches long x 24 inches high. It is capable of ±10°C at 1200°C throughout the work envelope. It includes a Honeywell UDC3200 program control and an over-temperature protection system plus a Honeywell DR450T circular chart recorder.
A heavy-duty electric motor lifts the counterbalanced furnace shell 25 inches to allow for loading. The series of silicon bars are loaded into a rack system and placed in the furnace. The first unit was shipped to the customer’s research and development facility in the United States, and the second furnace was shipped to the manufacturer in China.