Design considerations for charge preheating ovens

Driven by safety, more and more cast houses install preheating ovens for pre-heating and drying of sows, ingots and scrap before charging into a melting furnace. While preheating of the furnace charge enhances safety and improves fuel consumption at the same time, there are issues that must be addressed to avoid introducing new safety hazards. Special attention must be paid to issues like aluminium dust and combustible contaminants of materials that are charged into a preheating oven as these ovens start their cycle at a temperature well below the auto ignition temperature. Using a preheating oven without the proper technical considerations may therefore lead to exchanging one risk for the other. This paper addresses the design considerations that lead to safe and efficient installations for optimum pre-heating of scrap prior to melting.