Multitubular once-through boiler

Abstract

A multitubular once-through boiler which exhibits an excellent heat transfer efficiency and requires a relatively smaller installation area. The multitubular once-through boiler comprises a combustion device, a ring-shaped upper header which functions as a vapor chamber, a ring-shaped lower header which functions as a water chamber, a plurality of vertical water-tubes connecting the upper and lower headers to form a single-row ring-shaped water-tube wall, a combustion chamber which is a cylindrical inner space surrounded by the water-tube wall, and a ring-shaped combustion gas passage formed between the water tube wall and an outer wall of the boiler. The water-tubes each has a spiral channel grooved on the surface thereof and is in contact with adjacent water-tubes. The area next to each two adjacent water-tubes, on the side of the tubes facing the outer wall of the boiler, has a barrier plate disposed in contact with the water tubes. The barrier plate has an approximately V-shaped cross-section corresponding to the configuration of said area. The multitubular once-through boiler may further comprises a partition wall for dividing the cylindrical inner space of the water-tube wall into the combustion chamber and a flue.