| 摘要 |
A heat exchanger for a boiler comprises a plurality of parallel tubes (4) intended to be lapped, in use, by a hot gas and within which a fluid to be heated is intended to flow. At least one manifold duct (5, 6) places in communication the ends of two or more tubes (4) in order to distribute therein, in parallel, the fluid to be heated. A casing (2), which at least partly surrounds a space (20) in which the tubes (4) are placed, comprises a peripheral frame (21) defining an opening (22) for access to said space (20). The frame (21) comprises at least a first and a second side (31, 32) which are adjacent and provided on separate bodies, at least one of which is made of aluminium or aluminium alloy with a coating of brazing substance. The manifold duct (5, 6) comprises at least two zones having different cross - sections in order to distribute in a substantially balanced manner the flow of fluid to be heated within the two or more tubes in parallel. |
