Device for heating air by flue gases

摘要

One or more tube sections (2) mate with a supply flue (1). Each section (2) comprises heat-exchange tubes (3) attached to tube plates (4). A device for protection of the heat-exchange tubes (3) against abrasive wear incorporates at least one screen (5) formed by corrugated sheets facing each other and mating along convex portions, whereby cells (7) are defined, e.g. of bicuspid or hexagonal cross section.