No. 857 is an electrically-heated 500°F (260°C) walk-in oven from Grieve, currently used for annealing plastic. Workspace dimensions are 7′ wide x 12′ deep x 7′ high. 100 KW are installed in Incoloy sheathed tubular heating elements to heat the oven chamber, while a 17500 CFM, 15-HP recirculating blower provides horizontal airflow to the workload.
The oven has 4″ thick insulated walls, plus an aluminized steel interior and exterior. The door sill on this unit was eliminated and both oven doors are equipped with drag seals. Wear bars are installed on the sides of the workspace to protect the ductwork.
A 975 CFM powered forced exhauster and motorized dampers on the intake and exhaust accelerate cooling of the oven chamber.