摘要:
The gas is preheated by means of at least one screen disposed transversely relative to the flow of gas penetrating into the enclosure. The screen is provided with passages for the flow of gas and is fixed inside a peripheral wall to define a channel to enable the gas to flow through the preheating apparatus, it is also provided with fins which project from its surface, the screen and the fins being made of a refractory sheet material, in particular a sheet of laminated graphite.