February 12, 2008
The Grieve Corp.'s No. 837 is a 1,450-degree-F, electrically heated tempering furnace used for preheating prior to welding and for postwelding heat treatments.
Measuring 60 in. by 60 in. by 60 in., the furnace has 180 kW installed in nickel-chrome wire coils, supported by a stainless steel framework, that provide heat to the load. It also has a rear wall-mounted, heat-resisting-alloy recirculating fan, powered by a 25-HP motor with V-belt drive and water-cooled bearings.
Insulated walls 8 in. thick comprise 3 in. of 2,300-degrees-F ceramic fiber and 5-in. block insulation, and 7-in. floor insulation is made from 5 in. of 2,300-degrees-F firebrick and 2 in. of block insulation.
The furnace features an air-operated vertical lift door and several safety and control components, including a programming and temperature recorder; SCR power controller; manual-reset excess temperature controller with separate contactors; and a recirculating blower-airflow safety switch.