Heat exchanger connected downstream of hot blast cupola furnaces (see Cupola furnace) which is fired by hot stack gas preheating the blast required for combustion to approximately 600° C. (Fig. 1, Küttner GmbH)

Additional references:

Cupola furnace network diagram
Blast pressure
Hot blast nozzle
Hot blast stove
Blast rate

  • Picture 1: Recuperator system at Japanese client (Source: Küttner GmbH & Co. KG)