June 17, 2013

No. 939 is a 2000°F (1093°C) gas-heated box furnace from Grieve used for preheating metals prior to forging. Workspace dimensions measure 72″ wide x 36″ deep x 18″ high. 700,000 BTU/hr is installed in two natural gas burners with floor mounted combustion air blowers.

This furnace features 7″ insulated walls made with 5″ of 2300°F ceramic fiber and 2″ of 1700°F ceramic fiber. The 7″ floor is comprised of 4.5″ of 2300°F firebrick and 2.5″ of 1900°F block insulation. A firebrick plate hearth is supported by firebrick piers and the unit has a manually operated vertical lift door.

No. 939 also includes a digital indicating temperature controller, manual reset excess temperature controller with separate contactors, and a fused disconnect switch.