No. 989 is an electrically-heated, 2000ºF (1093ºC) inert atmosphere furnace from Grieve, currently used to process fabricated parts at the customer’s facility. Workspace dimensions measure 30” W x 48” D x 30” H. 57KW are installed in nickel chrome wire coils supported by vacuum- formed ceramic fiber to heat the unit, while a roof-mounted, heat-resisting alloy circulating fan powered by a 2 HP motor with V-belt drive maintains the inert atmosphere for the workload.
This Grieve furnace features 7” thick insulated walls, comprising 5” of 2300ºF (1260ºC) ceramic fiber and 2” of 1700ºF (927ºC) ceramic fiber, plus 7-1/2” floor insulation, comprising 4-1/2” of 2300ºF (1260ºC) firebrick and 3” of 2300ºF (1260ºC) block insulation. An alloy roller rail is supported by firebrick piers and the alloy loading fixture (shown in photo) with five 200 lb. capacity alloy shelves is provided with an external support roller rack to hold the loading fixture directly in front of the furnace’s workspace for easy loading/unloading. The unit also has an electrically-operated vertical lift door.
Special Grieve inert atmosphere construction includes a continuously welded outer shell, high-temperature door gasket, sealed heater terminal boxes, inert atmosphere inlet and inert atmosphere outlet.
Controls on No. 989 include an inert atmosphere flow meter and pressure regulator, digital programming temperature controller, manual reset excess temperature controller with separate contactors and a strip chart recorder.