1. The fin is divided into two symmetrical halves, the tube wall is pressed from both sides, and the tube wall is welded by resistance welding, leaving a certain gap in the middle; 2. Two round tubes can share a set of fins, called double-tube H-fins, or only one round tube can be placed in the middle, called single-tube H-fins. 3. The heat exchanger composed of H-shaped finned tubes is closely arranged, and the tube bundles are arranged in a row. Influence of H-fin structure on ash deposition and wear: The gap between the two pieces can use the flow of flue gas and scour the ash deposition, because the flue gas has a higher flow rate at the gap; the tubes are arranged in a row, and the resistance Small wear and tear; H-shaped fins can effectively utilize the flow space and maintain a large fin area and finning ratio; The thickness of the fins can be arbitrarily selected according to the needs of anti-wear; The fins are parallel and independent of each other, without helix angle effect, thus facilitating ash removal.