Lucifer Furnaces designed a multi-unit modular pot furnace system for an aerospace manufacturer in the United States. The end user is adding these furnaces to existing pot furnaces in order to increase heat-treating capacity. Each of the four furnaces is connected to a single freestanding NEMA 1 control panel, and each furnace is heated electrically with 18 kW of power to coiled elements in removable holders on all four sidewalls.
The units are insulated with 5 inches of multilayer insulation consisting of dry-fit hot-face lightweight firebrick backed by cold-face mineral wool. A vestibule at the top of each furnace reduces heat loss between the pot wall and firing chamber. Onboard controls include Honeywell DC3500 digital multi-programmable cascade controllers that automatically interpret multiple thermocouple readings and adjust the inside/outside pot temperature to achieve the desired setpoint. The temperature is monitored with control thermocouples in the firing chamber between the heating elements and pot wall, as well as separate sheathed thermocouples located in the pot.