A large international manufacturer will used two walk-in ovens to heat up molds to 220°F (105°C), with each mold weighing approximately 900 lb. The ovens, supplied by Lewco Inc., contain a custom rack with five shelves capable of handling up to five molds per batch.
The preheating ovens include a rear-mounted heater box with a heat capacity of 72 kW and an 8,000 cfm high efficiency circulation fan that delivers dual airflow evenly throughout the workspace. They are also furnished with zero speed switches on the fans in place of differential-pressure switches to eliminate possible shutdowns.
Each oven has a local control panel mounted to the rear wall. The panel includes all motor starter circuits, temperature controls, PLC and safety circuits. Each PLC communicates via Ethernet to the remote touchscreen HMI, which is capable of controlling up to six ovens in total. In addition to the standard thermocouple located in the supply plenum, Lewco supplied five thermocouples located on each shelf of the rack.