| 摘要 |
A water boiler comprising a housing for the water, which is comprised of front, rear and side walls, the side wall ends being connected to the rear and front walls by external fillet weld seams. A tube is mounted in outwardly flaring apertures in the front and rear walls, and the opposite tube ends protude beyond these walls and are connected thereto by external fillet weld seams. The tube consists of a sheet metal blank having two abutting edges extending the length of the tube and an external weld seam fluid-tightly connects the abutting edges between two adjacent ones of a plurality of circumferentially spaced and longitudinally extending sheet metal profiles affixed to the inner surface of the tube. A combustion chamber is mounted within the tube and is surrounded by the sheet metal profiles which operate as flues for combustion gases generated therein. A fuel burner inlet is arranged to burn fuel in the combustion chamber, and a combustion gas discharge is in communication with the flues for removing the combustion gases. |
