| 摘要 |
A multi-stage hot air heater is provided to reduce loss of heat and achieve improved efficiency of heat exchange by allowing smooth flow of outdoor air and combustion gas. A multi-stage hot air heater includes heat exchange plates stacked into multiple stages. Each heat exchange plate includes a plurality of square pipes and front pipes welded with each other in a main housing(2). The square pipes of the heat exchange plate are communicated in a zigzag way through communication portions(16b-16e) formed at both sides of the main housing. The lowest communication portion is connected to a combustion chamber equipped with a burner(10), and the highest communication portion is connected to an outdoor gas discharge pipe(18). Outdoor air which is compulsorily supplied by an air blower(20) in the main housing is heat-exchanged while passing through a heat exchange path formed between heat exchange plates, and discharged through an air discharge port(22) of the main housing. |
