Air preheater, or boiler preheater, is an important boiler part. It can be divided into two kinds, Tubular type air preheater and Vertical type air preheater. Air preheater pipe type, mainly using industrial furnaces or smoke waste heat boiler combustion air preheating furnace enter, such not only improves the thermal efficiency of the stove and reduce the environment pollution. Due to the gas - gas combustion on both sides of the heat exchanger, in order to strengthen small coefficient of heat transfer, usually installs the fin-root on both sides. Typical of the air preheater, its shape is commonly, main components for vascular cuboid, shell and partition.