This picture shows a vertical section through the gas space:

At the bottom, the two oil burners can be seen, and the cooler incoming gases are evident in the base of the mixing section. Gases mix rapidly in the turbulent cyclonic flow in the base section and attain to a mixed temperature of 879°C in the upper section between the choke and the exhaust.

At the top of the furnace the ejector nozzle and the cold air stream issuing from it can be seen.